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26th Annual Midwest Ecology & Evolution Conference March 17-19, 2006 St. Louis, Missouri |
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Below are the posters being presented at the conference, with abstracts. Use to "Edit", "Find" menu on your browser to search for topics of interest to you!
101. Community resistance of inland lakes and the distribution of an exotic cladoceran, Daphnia lumholtzi Author: Susan Pasko, Kent State University Keywords: zooplankton community structure, invasive species Area: Ecosystem and Community Ecology
There has been increased concern in recent decades regarding the growing rate of invasion of non-indigenous species to aquatic habitats and their potential to disrupt the integrity of freshwater systems. A recent invader to Ohio lakes is the cladoceran, Daphnia lumholtzi which was first reported within the state in 1993. Samples from the Ohio Environmental Protection Agency from the years 1991 to 1997 and contemporary samples taken during the summer of 2005 were used to investigate the current distribution and establishment of D. lumholtzi in Ohio lakes. The presence of D. lumholtzi was detected in 20 of the 72 public lakes surveyed. Many of the invaded localities exhibit heavy boating traffic or are downstream from invaded lakes, indicating that flowing water and human vectors are important means for dispersal of the species.
Many of the lakes surveyed have strong potential for invasion by D. lumholtzi, yet have been able to resist invasion thus far. The presence or absence of cladoceran species within the lakes was examined to investigate if interactions with native species may be responsible for controlling the establishment of D. lumholtzi. The organisms that exhibited the highest correlation with D. lumholtzi were Daphnia longiremis, Daphnia parvula, and Ceriodaphnia species. Low correlations were associated with Bosmina longirostris and Diphanosoma birgei; furthermore the populations of these species often exhibited decreasing trends following the arrival of D. lumholtzi. Whether this decline is due to the establishment of the exotic species or the result of natural cyclical abundances of zooplankton requires further investigation.
102. Defining edge gradients using plant species composition in oak-hickory forest patches Authors: Elise M. Tulloss and Scott J. Meiners, Eastern Illinois University Keywords: depth of edge, environmental gradients, forest understory Area: Ecosystem and Community Ecology
Forest conservation is greatly enhanced with an increased understanding of the transitional nature of edges. Most forests in east-central Illinois exist as small patches, making the region an ideal location for studying edge effects. The objective of this study was to identify the mechanisms and processes that determine gradients of plant composition and to develop a predictive model of edge effects using plant species composition as an indicator of edge influence. A large data set was gathered to relate species composition to several environmental and community composition variables. The data was analyzed in several multiple regressions to find the most important variables controlling edge responses. The study system had a sharply defined edge gradient, with vegetation cover highest at the edge and decreasing dramatically 15-30 meters into the forest. Percent canopy cover, distance from the edge, and plot slope were the most important controllers of edge influence for most responses. Edge aspect had no effect on the response of the community. Canopy cover controlled light intensity on the forest floor, distance reflected the plot landscape position, and slope reflected the control of microtopography on plant growth. An ANCOVA found that total cover did not change with distance on plots with steep slopes. Besides providing a useful tool for predicting the effect of the edge on plant composition, this study also found microtopography to be an important controller in this system, which has previously been overlooked in the study of edge effects.
103. Soil feedback as a mechanism of plant community response to invasion Authors: Jeremy R. Klass and Scott J. Meiners, Eastern Illinois University Keywords: none Area: Ecosystem and Community Ecology
The intent of my study is to determine the impacts of Microstegium vimineum, (Japanese stiltgrass) invasion on the soil community as a potential determinant of plant community structure within the Buell-Small Succession Study (BSS). In the BSS site, M. vimineum strongly influences species richness and alters plant community composition. The BSS gives me a unique opportunity to link long-term restoration dynamics with specific biological mechanisms. I am hypothesizing that M. vimineum is affecting species diversity and composition through negative biofeedback mechanisms within the soil. To address this research question, soil samples were taken directly from areas invaded and uninvaded by M. vimineum in two sites: an abandoned agricultural field and an old growth forest. A preliminary soil inoculum experiment was performed using 10 mL of either live or sterilized soil inocula added to sterile greenhouse media. Poa pratensis seeds were germinated and transplanted into soil tubes that contained one of four inocula treatments and were allowed to grow over a 6 week period. At the end of the growing period, plants were harvested, and total above ground biomass was determined. To assess the ability of M. vimineum to alter AM (arbuscular mychorrizae) colonization, root material was collected and Trypan blue stain used to measure colonization. Plants grown in sterilized soil outperformed plants grown in unsterilized soil with regard to biomass. Currently we are attempting to quantify AM colonization. A larger experiment will be conducted using the same protocol using three common understory species as focal plants.
104. Functional dynamics of plant communities from a long-term study Authors: Timothy Rye and Scott Meiners, Eastern Illinois University Keywords: plant community ecology Area: Ecosystem and Community Ecology
Functional trait analyses of plant communities have addressed a variety of important issues in plant ecology. However, most of these studies have not been based on long-term datasets and as a result do not account for spatial and temporal contingencies that could affect successional trajectories, nor do they consider how the trait composition within a community can change over time. I present the initial progress of a study using long-term species abundance data from the Buell-Small Succession study in the Piedmont Region of New Jersey. The purpose of this research is to determine the presence of patterns in individual traits and functional groups over time. In addition, functional traits will be used to determine whether exotic plant species possess trait values, or clusters of trait values, that differ from native taxa. Trait values were recorded from literature sources where appropriate, as well as from field sites. Functional groups will be determined using statistical clustering techniques and then analyzed using an appropriate method of ordination. Temporal patterns will be discerned by analyzing mean values for individual traits and for functional groups. Describing long-term patterns of trait and functional group abundance will present me with a unique opportunity to analyze the effect of environmental disturbances on successional trajectories, as well as the effect of invasive species on community structure. The results of this study will have an impact on our understanding of the utility of functional plant ecology to explain plant community dynamics.
105. The impact of artificial lake destratification on the zooplankton community in the Phase II Restoration of Campus Lake Authors: Alicia M. Jacobs and F.M. Wilhelm, Southern Illinois University - Carbondale Keywords: none Area: Ecosystem and Community Ecology
Ecosystem restoration by humans generally requires a hands-on approach and causes disturbances different from those that led to the initial degradation. For example, lake aeration is often used to alleviate low oxygen conditions in highly degraded lakes. However, the impact of aeration on the pelagic community, including zooplankton is often ignored. The community dynamics of zooplankton are significant because of the important role of large cladocerans such as Daphnia in trophic cascades and the reduction of algal biomass to improve water quality. An aerator was installed in the deepest part of Campus Lake on Southern Illinois University’s campus in June 2005. Whole-lake changes included i) increased oxygen in the bottom waters, which in turn expanded the suitable habitat for biota and ii) increased water temperature throughout the entire water column. To examine the effect of aeration on the zooplankton community, sampling was undertaken at two sites, one near the aerator and a reference site removed from the aerator. Differences in zooplankton composition as a result of the aerator and impacts on the whole-lake zooplankton community will be discussed, with the ultimate goal to determine if the restoration action is indeed a benefit to the ecosystem.
106. The role of dissolved oxygen tolerance in the displacement of Gammarus fasciatus by Echinogammarus ischnus in the North American Great Lakes Author: Joshua Osborn, Bowling Green State University Keywords: none Area: Ecosystem and Community Ecology
Ecosystem engineers are
species that regulate the environment and biotic interactions, and
thus affect community structure and interactions. As invading
species, they may in fact alter abiotic conditions to facilitate the
invasion success of associated organisms that coexist with the
invader in its indigenous ecosystem. In the Great Lakes, probably
the most influential benthic invaders are the dreissenid bivalves,
zebra mussels (Dreissena polymorpha) and quagga mussels (D.
bugensis). Following this invasion, other benthic species have
invaded that are closely associated with dreissenid druses. An
amphipod Echinogammarus ischnus is generally found among
dreissenid mussels and it has been hypothesized that they more
effectively use these refugia to avoid predation than does the
indigenous species, Gammarus fasciatus. Recent study in our
lab (unpublished) has found evidence that E. ischnus is more
tolerant of low dissolved oxygen (DO) than G. fasciatus.
Additionally, the interstitial areas among dreissenids can contain
decomposing organic matter (OM) and thus low dissolved oxygen. I
propose two experiments to examine effects of low DO and dreissenid
use by G. fasciatus and E. ischnus. The first
experiment will compare the ability of the invasive E. ischnus
and native G. fasciatus to utilize interstitial habitat under
variable OM conditions among dreissenid druses. The second
experiment will investigate the role of differential DO tolerances
of these amphipods, and thus, use of druse refuge in predator-prey
interactions. 107. Bottom-up effects triggered by an El Nino event in a vertebrate community in semi-arid Chile Author: Bonny J. Dieter, M. Andrea Previtali, and Peter L. Meserve, Northern Illinois University Keywords: none Area: Ecosystem and Community Ecology
To determine how climate affects resources and consumers, we measured rainfall and recorded changes in three trophic levels before, during and after the occurrence of the intense 1991-1992 El Niño event at Fray Jorge National Park in Chile. From 1990-1994 we recorded annual peaks in plant cover and seed density, monitored rodents through the use of live traps in control and predator exclusion plots, and surveyed predator abundance and diversity. Predator diet preference was estimated from scats and owl pellets collected in the study area.
Annual rainfall during El Niño event was five times higher than a normal-dry year. As a result, plant cover and seed density increased accordingly. Probably due to more resources, rodent population size increased over twenty times after their reproductive season. Similarly, due to the rise in prey availability, predators increased their consumption of mammals. At the same time we observed a numerical response in the predators and an increase in their diversity. When annual rainfall returned to normal, we observed the opposite trends at all trophic levels. Rodent populations in predator-exclusion plots exhibited similar dynamics as on the controls. The El Nino Southern Oscillation greatly influences resource availability in this semi-arid community. The dramatic response observed leads us to conclude that this community is mainly controlled by bottom-up influences whereas predators did not appear to drive prey dynamics.
108. Forest floor invertebrate communities in the Cleveland, Ohio Metroparks and the potential impact of exotic isopods Authors: Sarah Osicka, Adam Zurkey, and Chris Stanton, Baldwin-Wallace College Keywords: ecology, Ohio, forest floor, invertebrates, sowbugs Area: Ecosystem and Community Ecology
Ecological communities within Cuyahoga County, Ohio are dynamic systems that have been changing in response to numerous environmental factors, such as urban development, pollution, exotic species, and global climate change. The forest floor community in particular has been impacted by multiple factors but these local communities have been little studied and the effects of these disturbances are still largely unknown. In order to better understand the current composition of this community in northeast Ohio, forest floor invertebrates were collected during the summer of 2005 in mature hardwood and pine-dominated stands in the Cleveland Metroparks. Collections methods included pitfall trapping, Berlese sampling, and hand collecting at three sites within each forest type. Traps were emptied weekly for ten weeks during the months of June, July, and August. Dominant invertebrates included sowbugs (Order Isopoda), springtails (Order Collembola), and spiders (Orders Araneae and Opliliones). The spiders were the most common invertebrates in the pine community but sowbugs dominated the hardwood sites. These exotic sowbugs (Oniscus asellus) may be having a major impact on the structure of the forest floor community, in terms of species richness and abundance, and warrant further investigation. For example, preliminary experiments indicate that these sowbugs may be consuming termite populations and in turn creating a build-up of woody debris and potential fire hazards.
109. Comparative floral ecology of two endemic sympatric Potentilla species (Roasacea) Author: Elizabeth Winkler, Saint Louis University Keywords: none Area: Ecosystem and Community Ecology
Related species exhibiting the same pollination syndrome have the potential to compete with each other for the same seasonally available guild of pollinators. In Oregon, native wildflowers Potentilla gracillis and P. glandulosa grow in freely mixed patches and have overlapping blooming periods. Both species have bowl-shaped flowers and traditional hypotheses suggest that they would fall under the ‘generalist’ pollination syndrome. The phenology of each species was observed; the pollinators of both species were collected and identified, and had pollen loads analyzed for fidelity. The rate of pollination was assessed through examining pollen tube growth and seed set under natural ‘open’ pollination compared to flowers that had pollinators excluded. There was considerable overlap in the species identity of insects that visit both flowers. However, individual insects were rarely seen visiting both Potentilla species sequentially. Insects captured on P. glandulosa showed a higher fidelity to both Potentilla spp. in general, and to P. glandulosa in specific. Insects captured on P. gracillis were more likely to have visited other genera of wildflowers in the area, as well as multiple Potentilla spp. Open flowers of both species have a high rate of pollination (>90%) as compared to insect-excluded flowers. However, bagged flowers still achieved seed set, indicating a possible automatic self-pollinating mechanism.
110. Cation exchange capacity and the distribution of aquatic macropyhtes Author: James Montante, A. Amin, G. Patel, M. Tracy-Bee, and R. A. Hough, Wayne State University and University of Detroit Mercy Keywords: macrophytes, sediments, cation exchange capacity, community composition Area: Ecosystem and Community Ecology
Sediment cation exchange capacity was correlated to the occurrence of three aquatic angiosperms in East Graham Lake in Lake Orion, Michigan. Cation exchange capacity is a traditional measure of soil fertility that estimates the number of cations a given amount of sediment or soil may hold. Cation exchange capacity and the percent cover of each plant were measured in 17 quadrats along transect lines running through persistent beds of Potamogeton pectinatus, Myriophyllum exalbescens, and Elodea canadensis. Sediments were saturated with sodium acetate and then rinsed with ethanol to remove excess sodium ions not attached to the sediment. Sediments were then washed with ammonium acetate to displace the sodium ions attached to the sediment. Sodium concentration of the resulting supernatant was measured by atomic absorption. While significant differences in cation exchange capacity were seen between the three beds, the within bed percent cover and sediment cation exchange capacity data did not show a significant correlation.
201. Novel form of reflex bleeding: first evidence of a defense secretion exhibited by a red velvet mite Authors: Jacob T. Ark, E.J. Rellinger, J.B. Benoit and J.A. Yoder, Wittenberg University Keywords: terrestrial, red mite, defense secretion Area: Behavioral Ecology
Population bursts of tiny, brightly colored, red terrestrial mites (Balaustium sp.) occur each Spring. These mites are recognized as fast moving, red specks, crawling over building walls, sidewalks, and other outdoor structures. To date, two puzzling ring-shaped structures (urnulae) of undescribed function situated on the dorsum have been used for identification purposes, distinguishing Balaustium from other red terrestrial mites. In this study, urnulae were observed protruding and secreting red fluid in response to disturbance to the mite (organic solvent submersion or bright light exposure). Ammoniacal silver nitrate staining, scanning electron microscopy and histological analysis demonstrate morphological consistency between urnulae and exocrine glandular structure, featuring innervated muscle and secretory vesicles. Mealworm larvae (Tenebrio molitor) were coated with mite secretion extract and offered to predatory ants (cornfield ant, Lasius alienus, and black carpenter ant, Camponotus pennsylvanicus). Ant attacks declined by >70% when urnulae secretion extract was applied, indicating a defense (allomone) function. Ants appeared indifferent rather than irritated, likely due to secretion-induced blocking of chemosensory receptors in the antennae, generating a protective shield allowing the mite to appear ‘invisible.’ Exposing Balaustium to an extract derived from urnulae secretion activated an excited dispersal response, signifying this secretion conforms to semiochemical parsimony by doubling as an alarm pheromone in event of an injury. Balaustium and ants reacted similarly in tests run using mite body contents compared to secretion extracts, implying urnulae secretion active ingredients are blood-borne. Both secretion release and mode of action are reminiscent of that in reflex bleeding occurrences of aposematic beetles.
202. The effects of behavioral syndromes on learning in smallmouth bass (Micropterus dolomieui) Authors: Kelly Lynne Smith, Daniel Wiegmann and Jeffrey Miner, Bowling Green State University Keywords: behavioral syndromes, smallmouth bass, learning
Area: Behavioral
Ecology Much like human beings, animals have a tendency to exhibit unique behavioral tendencies such as those we would refer to as extroverted or introverted. Individual behavioral patterns in animals have been referred to as coping styles, temperaments, axes or strategies and all of these terms refer to a tendency to act in a similar manner throughout multiple contexts. One example of this would be an individual acting bold across mating, foraging and predator avoidance contexts. These suites of correlated characteristics are termed “syndromes” in evolutionary ecology, and so these behavioral correlations are known as behavioral syndromes. While work has been done on the effects of behavioral syndromes on areas such as predator avoidance, dispersal and foraging, little work has been done regarding its influence on learning. I plan on testing for behavioral syndromes in smallmouth bass (Micropterus dolomieui) while examining how a syndrome may affect the speed at which an individual learns. Understanding how syndromes influence learning allows us to make conjectures as to why individuals react differently to their environment and may explain how organisms with different traits adapt in dynamic environments.
203. A comparative study of avian hearing: seasonal effects on auditory sensitivity, pitch perception, and pitch tracking Author: Kenneth Henry, Purdue University Keywords: communication, receivers, birds, auditory brainstem response Area: Behavioral Ecology
Seasonal patterns of vocalization may be reflected in the auditory capabilities of receivers, but few studies have investigated this possibility, including only one study of birds. To build upon this research, I am conducting a study of auditory sensitivity, pitch perception, and pitch tracking in House Sparrows and White-Breasted Nuthatches based on noninvasive electrophysiological measurements of the auditory brainstem response and frequency-following response. Here I describe the methodology of the study, and present preliminary data from House Sparrows. This study will contribute to our understanding of factors that influence the evolution of avian hearing (e.g. signal seasonality, signal frequency modulation), and is broadly relevant to research concerned with correcting hearing impairment in humans.
204. Activity effects of Acanthocephalus dirus on its intermediate host Caecidotea intermedius Authors: Daniel J. Tobiansky, J. A. Talkington, and T. C. Sparkes, DePaul University Keywords: Acanthocephalus dirus, Caecidotea intermedius, behavior Area: Behavioral Ecology
Larval stages of the acanthocephalan parasite Acanthocephalus dirus induce changes in activity in the freshwater isopod (Caecidotea intermedius), which increase their chances of being consumed by their definitive host (e.g., sunfish, creek chub). This research was conduced in a laboratory setting. We extended this approach to determine whether parasite presence correlated with changes in activity in the field. Activity trials were run in Buffalo Creek (Kildeer, IL) to determine the effects of differing larval stages of A. dirus on activity of C. intermedius. Each trial lasted 15-minutes, during which we recorded the number of grids (1cm) that an individual crossed. Isopods were then transported to the laboratory and the number and developmental stage of A. dirus recorded. We found that there was no significant effect of infection status on the activity of C. intermedius.
205. Inability to absorb water vapor from the air illustrating enhanced predatory capacity of the red velvet mite Authors: Justin L. Tank, J.T. Ark, J.B. Benoit, E.J. Rellinger, and J.A. Yoder, Wittenberg University Keywords: water balance, Balaustium sp. Area: Behavioral Ecology
We report water balance characteristics of Balaustium sp. [velvet mites] with the goal of determining its primary source of water to address fundamental questions related to features for survival, habitat preference, and spread into new regions. These mites are brilliantly colored red mites that are ubiquitously distributed on the walls of buildings each Spring. In this study, mites were collected and stored at different relative humidities to determine water content, dehydration tolerance, and water loss rate. Characteristics of this mite revealed that it is xeric-adapted and capable of withstanding desiccation, as exhibited by a slow water loss rate of 2%/h and a unique ability to lose over half of its 71% body water content. Unlike most mites, Balaustium sp. lost water at relative humidities close to saturation, indicating that it cannot absorb water vapor from the air. Furthermore, scanning electron micrographs of the mouthparts showed no salt accumulation, which is a common characteristic of acarine vapor uptake mechanisms. Rather, microscopic observations revealed chelicerae that are modified into a sword-like stylet ideal for stabbing prey. Notably, these mites have a limited ability to drink free water. Thus, the primary water source for these velvet mites is likely their food, the blood and tissue fluids imbibed from scale insect prey. Their mouthpart design and inability to absorb water from the air suggest that this mite must be an exceptional predator to acquire the proper amount of water necessary for survival.
206. Effects of a mechanical disturbance on parasite-related change in antipredator behavior of Caecidotea intermedius (Isopoda) Authors: Evan Korkofigas and T. C. Sparkes, DePaul University Keywords: acanthocephalan, parasite transmission, Acanthocephalus dirus, host manipulation, behavioral response Area: Behavioral Ecology
The acanthocephalan parasite Acanthocephalus dirus induces changes in antipredator behavior of the intermediate host Caecidotea intermedius, which increases the probability of transmission to definitive hosts (creek chub, sunfish). To determine whether behavioral modifications are species-specific (host and non-host), we examined the attraction of infected isopods to host predators. In a field based experiment we quantified proximity of parasitized males to water disturbance. Isopods were placed individually into an elongated tank with evenly distributed rock refuge and leaf discs. A current was generated at one end behind a mesh barrier while individuals moved freely in the tank. Results showed infected males preferred being near the disturbance. There was no difference in feeding or refuge use between disturbed and calm waters. We suggest that infected C. intermedius are attracted to movements independent of species–specific predator cues.
207. Multi-attribute decision making and asymmetric dominance in swordtail fish (Xiphophorus cortezi) Author: Heather Luedecke, Bowling Green State University Keywords: decision-making, swordtail, multiple ornaments, mate choice, asymmetric dominance Area: Behavioral Ecology
Recent research indicates that females likely use several traits to judge potential mates. Understanding how females weight multiple cues in decision-making will facilitate understanding of how sexual selection modifies male traits. In situations where multiple cues are used to assess potential mates, the reason-based asymmetric dominance effect may influence the decision process. Consider the situation in which two options A and B differ across two attributes X and Y—where A is superior to B on Y and inferior to B on X—and suppose that A is preferred to B in a binary choice test. The difference between the two options on dimension Y has a stronger influence on choice than the difference between the two options on X. Suppose that an additional option C is added to the choice set, where C is similar to A on dimension X and inferior to B on both dimensions. The inferiority of C on dimension Y reduces the perceived difference between A and B on this dimension increasing the preference for option A. Females of the swordtail (X. cortezi) chooses males according variation in length and bars. Different treatments of total length of the male and number of vertical bars will be presented in binomial tests. Model males will be used in place of live males. Females will be exposed to two choice sets. The proportion of time a female spends with the males will be assessed and the difference across choice sets will be tested against zero with the paired t-test.
208. Raccoon (Procyon lotor) foraging response to predator scent Author: Amanda Oliver, Saint Louis University Keywords: none Area: Behavioral Ecology
Urban and rural raccoon densities are increasing leading to more frequent contact with humans and domestic animals and increased risk of disease transmission. Areas with increasing densities have higher levels of nest predation; a potential cause of migratory bird decline. Reduction and extirpation of large predator populations may cause increasing raccoon density. To determine if raccoons respond to predators, an indication that predators affect raccoon density, I tested raccoon foraging response to wolf, coyote, bobcat, and Mt. lion urines. During four nights each month, I placed one of the four predator urines next to one depletable food patch at each of twelve locations. After one night of raccoon foraging, I weighed the amount of food remaining in control and experimental food patches. In June, wolf urine significantly decreased raccoon foraging (n = 8, Ts = 2, T < 3, P < 0.05). In June and October, raccoons consumed significantly more from patches with coyote urine nearby (n = 6, Ts = 0, T < 0, P < 0.05), (n = 7, Ts = 1, T < 2, P < 0.05). For five months, no predator urine had a negative effect on raccoon foraging except wolf urine in June. Lack of a negative response to predator urine suggests that these predators do not present a threat to raccoons. Therefore, it is unlikely that these predators control raccoon density.
209. Evolution of female leader preference in the genus Neoconocephalus (Orthoptera: Tettigoniidae) Author: Katy Klymus, University of Missouri - Columbia Keywords: none Area: Behavioral Ecology
In acoustic signaling insects females are know to prefer the first of two calls presented in close succession of one another. This leader preference is suggested to result in males competing with one another to be the preferred leader, resulting in an imperfect synchronization of leading and following calls. Thus, female leader preference is often observed in species with synchronization of discontinuous calls. However, mechanisms for the leader preference are unknown. The preference may be due to a pre-existing bias of the female’s sensory system, or females prefer leading males because these males provide a benefit. Relative to the question of the evolution of this preference, both hypotheses predict different patterns of preference occurrence in closely related species. If preference was due to a pre-existing bias, the preference is expected among species with continuous song as well as those with discontinuous song. However, the second hypothesis predicts that this widespread pattern would not be observed, and even discontinuous calling species may not have the preference. Within the katydid genus Neoconocephalus, discontinuous songs evolved several times independently, allowing us to test these predictions. Females of N. spiza appear to have a strong leader preference. We tested for the leader preference in female N. nebrascensis using overlapping male calls and found no biologically relevant preference. Our results imply that leader preferences are not due to a pre-existing bias and probably evolved after the advent of discontinuous calls in the katydid genus Neoconocephalus.
210. Where do lizards sleep? A comparison of nocturnal perches of three Jamaican Anolis species Authors: Sonal Singhal, Michele A. Johnson, Jason T. Ladner, and Jonathan B. Losos, Washington University Keywords: Anolis, sleep, habitat use Area: Behavioral Ecology
Where animals choose to sleep may be important, as sleeping renders animals immobile and hypothetically vulnerable for long periods. As such, there is presumably an ecological component of sleep site choice, but few researchers have studied natural sleeping behaviors. We investigated the sleeping locations of three sympatric species of Jamaican Anolis lizards (Anolis valencienni, A. lineatopus, and A. grahami) that have evolved morphological, ecological, and behavioral adaptations to different microhabitats. In this study, we tested the hypothesis that these closely-related species choose sleeping sites that reflect these distinct microhabitat specializations. Further, we explored the relationship between sex and nocturnal habitat use by determining whether females and males differ in their nocturnal perches.
We compared lizards’ diurnal and nocturnal perch use by measuring perch height, diameter, substrate, and inclination. Our results showed that all three species choose significantly different perches for daytime activities than those perches on which they sleep. Specifically, lizards sleep on higher, narrower, and more horizontal perches than their diurnal perches. The three species vary in their nocturnal perch use in a pattern that reflects their differing habitat specializations. In particular, species that use the highest, narrowest perches during the day also use the highest, narrowest perches on which to sleep. Additionally, males and females exhibit differences in perch use, as differences between nocturnal and diurnal perches are generally greater for females than for males. Our analyses suggest that both interspecific and intraspecific characteristics are important in structuring nocturnal perch use.
211. The effects of regeneration and food limitation on growth and development time in wolf spiders Authors: Kerri Wrinn, Ann Rypstra, and George Uetz, Miami University (of Ohio) Keywords: regeneration, food limitation, wolf spiders Area: Behavioral Ecology
Autotomy (self amputation) of appendages in order to avoid predation is common to many animal groups. Several animals that can autotomize appendages can also later regenerate. However, autotomy and regeneration may lead to functional and energetic costs (i.e. reduced foraging and growth). Because autotomy has the potential to reduce foraging, an animal that is regenerating an appendage may be dealing with increased energetic costs while using reduced energy input. This may be particularly critical for animals that are food limited in nature. In this study, Schizocosa ocreata wolf spiders were used to address the costs of food limitation and regeneration separately, as well as the interactions between the two factors. Spiders were placed in four treatment groups based on autotomy of a leg and feeding regime: 1) Intact/ High feeding, 2) Autotomy/High feeding, 3) Intact/Low feeding, 4) Autotomy/Low feeding. After molting, spiders were weighed and their cephalothorax widths were measured to determine growth. Additionally the molt interval in days was noted to determine development time. Regeneration had no effect on mass, but well fed spiders were significantly larger than deprived spiders. Leg regeneration significantly reduced molt interval, while low feeding conditions significantly prolonged it. Cephalothorax width was largest in the well fed intact group with no difference between the other three groups. These results demonstrate that impacts of regeneration on growth and development time in spiders may be partially determined by level of nutrition.
212. Ontogenetic shift in sleeping perch height in Oxybelis brevirostris Authors: Chad E. Montgomery and Karen R. Lips, Southern Illinois University – Carbondale Keywords: Oxybelis, perch height, sleeping behavior Area: Behavioral Ecology
We examined the natural history of Oxybelis brevirostris in Omar H. Torrijos National Park (Cocle Province, Panama) from 15-Mar-2005 to 1-Dec-2005. We collected natural history, habitat, and morphological data on all individuals encountered along trails and streams within a 2.0 km2 area of the park. Oxybelis brevirostris is a medium-sized, diurnal, arboreal snake that forages, from arboreal positions, on ground dwelling lizards and frogs. At night, O. brevirostris sleeps off of the ground, coiled in the vegetation. We located 146 (49M:97F) individuals ranging from 22.2 cm SVL to 73.0 cm SVL. Of the 146 found, we located 125 at night while they were sleeping. Oxybelis brevirostris shows an ontogenetic shift in perch height while sleeping, with juveniles occupying lower perch heights. Higher perch heights likely afford more protection from predators, while lower perch heights reduce the energy expenditure associated with daily movements from perch sites to foraging sites.
301. Genetic component of a life history characteristic: initiation of spawning in smallmouth bass Author: Daniel Welsh, Bowling Green State University Keywords: none Area: Population Genetics
Changes in populations are the result of life history traits and environmental variability. Life history characteristics include such fundamental facts as number of offspring produced, life expectancy, and age of maturation. Environmental variability is important because the activities observed in populations may be partly due to their surroundings. It is also possible that both factors have an impact. Molecular techniques are a powerful tool used to study populations. I propose to quantify if there is a detectable genetic component to age at first reproduction of males in a population of smallmouth bass, Micropterus dolomieu, from Pallete Lake in north-central Wisconsin. Previous studies have found that the initiation of spawning in these fish does not occur at a specific age, but is strongly related to growth rates, which may be heritable or may simply depend on the environment (or a combination of the two).
I will characterize the genetic variability of the smallmouth bass born in 1999 by analyzing microsatellite DNA from individuals that first spawned at age two (in 2001) and four (in 2003). If the variability among the individuals that first reproduce as two year olds is different than that for those who spawn at age four, then this means the fish are from a few specific nests and, thus, there is a genetic component to this behavior. If the converse is found, this will support the idea that the environment impacts this characteristic. Age at first reproduction plays an important role in population stability and, so, it is important to understand the factors influencing the trait’s variability.
302. Epistasis and heritable genetic variance across an experimental bottleneck: a measured genotype approach Author: Joseph Jarvis, Washington University in St. Louis Keywords: none Area: Population Genetics
Identifying quantitative trait loci (QTL) underlying traits of interest allows the measurement of two locus genotypic values and the quantification of multi-locus interaction effects. Such measured genotype approaches facilitate a finer resolution of the evolutionary implications of epistasis and represent an improvement over traditional analyses using the interaction variance (VI) from biometrical variance partitioning. Since interaction effects among loci can contribute to all three genetic variance components, the heritable genetic (VA), dominance (VD), and interaction variance (VI), considering VI alone tends to underestimate the actual amount of epistasis present and obscure the role of epistasis in the evolutionary process. Empirical studies document extensive genetic interaction underlying many complex characters as well as the particularly important contribution that epistasis can make to the preservation of heritable genetic variance (VA) during and following population bottlenecks. Here, we report the results of a genome-wide scan for two-way epistasis in traits related to body size and growth in F2 mice from the LGXSM intercross as an initial step towards tracking the effects of known epistatic interactions across subsequent bottlenecked generations. Epistatic profiles vary from trait to trait but most often involve dominance x dominance interactions. Monte Carlo simulations of a severe population bottleneck using these empirically measured values predict the preservation of heritable genetic variance for both adult body weight and the weight of the reproductive fatpad over the expected value of VA = (1-F)VAO, an effect which peaks in the F7 generation. Such observations have important implications for various models of evolutionary change.
303. Genomic incompatibility in an interpopulation cross results from epistatic interactions at four major loci in the moss Ceratodon purpureus. Authors: Stuart F. McDaniel and A. Jonathan Shaw, Washington University and Duke University Keywords: none Area: Population Genetics
The evolution of post-zygotic reproductive isolation is a critical step in the generation of new species. The genetic basis of reproductive isolation, the causative evolutionary forces, and their biogeographic context remain largely unexplored, however, outside of a handful of model systems. Here we examine the genetic basis of outbreeding depression between geographically distant populations of the moss Ceratodon purpureus. We crossed a male from Ithaca, New York, USA, to a female from Otavalo, Ecuador, and cultivated 288 recombinant progeny. Molecular population genetic evidence indicates these populations exchange neutral genes. Nevertheless, approximately half of the hybrid progeny exhibited severely reduced growth rate at the juvenile (protonemal) stage; this low-fitness phenotype is almost completely absent in natural populations. To dissect the genetic basis of the dwarf phenotype, we constructed a linkage map using 121 polymorphic AFLP loci and restriction site polymorphisms in three nuclear loci. Using composite interval mapping we identified four autosomal QTLs associated with outbreeding depression. To understand the genetic interactions underlying this phenotype, we classified the hybrids as normal or low-fitness, and constructed a full-factorial ANOVA with the marker genotype at the marker most tightly linked to the four autosomal QTL peaks specified in the model. We found significant pairwise interactions between one QTL and the other three, and a nearly significant four-way interaction effect (p = 0.09). We found asymmetry in effects of introgression at all four loci. In addition to the loci implicated in hybrid breakdown, six regions of the genome exhibited significant transmission ratio distortion. Five of these were distorted toward the Ecuador (female) parent, while only the sex-determining region was distorted toward the New York (male) parent. Current work is aimed at 1) testing for correlations between the strength of outbreeding depression and geographic distance between populations; 2) testing whether QTLs that exhibit negative epistasis in a hybrid genetic background underlie locally adapted phenotypes in the New York or Ecuador populations; and 3) determining whether segregation distortion results from population divergence or genomic conflict occurring within populations.
401. Conservation of an endangered desert mussel: population dynamics and a complex life history Authors: Todd D. Levine, Brian K. Lang, and David J. Berg, Miami University (of Ohio) Keywords: none Area: Population Ecology
Freshwater mussels are arguably the most endangered animal taxa in North America. Desert mussels may experience a very different suite of natural and anthropogenic threats than mussels inhabiting rivers situated in the more extensively studied habitats of the Midwest and Southeast, likely due to very different hydrological dynamics. The range of Popenaias popeii, the Texas Hornshell, has been reduced to two populations in New Mexico and Texas. We initiated a mark and recapture study, an underutilized method in studying mussel population dyanamics, and are investigating larval host use, using both traditional and novel methods. We analyzed these data using program MARK to derive survival estimates and evaluate the relative importance of several factors on population parameters. Survival rates were generally high, but decreased during flooding, which is likely the primary cause of mortality. This is further supported by a preference for habitats that have low flow and are protected from flow by travertine shelves, root mats, and boulders. Initial host studies indicate that these obligate larval parasites may be physiologically compatible with a wide range of hosts, but field surveys revealed few infections. Collection of immunological data from field and laboratory collections is ongoing and will elucidate host use in the wild, substantially expanding the capabilities of traditional survey methods alone. These studies provide a basis for conservation efforts and are applicable to basic mussel biology, specifically how patterns of habitat and host use develop under various hydrological and ecological conditions.
402. Ecology and habitat selection of eastern tent caterpillars in Central IL Authors: Jennifer Pleasant, Eric Bollinger, and Ann Fitz, Eastern Illinois University Keywords: habitat selection, eastern tent caterpillars Area: Population Ecology
Eastern Tent Caterpillar moths (Malacosoma americanum) are known to select the branches of black cherry trees (Prunus serotina) as common oviposition sites. What is not well known is why they select particular cherry trees over others nearby. To answer this question, host trees and the next nearest black cheery trees without eggs were identified and data were collected on tree height (m). In addition, for trees with egg masses, measurements of egg mass height (m), aspect (direction the egg mass faced), location of egg mass on tree (top or bottom half), and canopy coverage were recorded. The average canopy coverage was found to be 36.4% coverage with 36 out of the 47 nests preferring to have canopy coverage of less than 50%. No differences were found in tree height between trees with and without nests (p > .05). For trees containing nests, caterpillars preferentially build or placed their egg masses facing north (p < .05).
403. The effects of source population size on plant performance in a prairie restoration Authors: William L. Stewart and Scott J. Meiners, Eastern Illinois University Keywords: restoration, small populations, prairie species Area: Population Ecology
Tallgrass prairies have been drastically reduced to a few remnant areas that are both small and isolated. As a result, species within these areas may be exposed to a significant level of inbreeding depression and loss in genetic diversity. Often, prairie restorations rely on seed collections from these small, isolated populations which may lead to the same fitness problems in the restoration. The study specifically addresses the question: Does the dependence on seed collections from small, isolated populations lead to loss of vigor in restored populations? Seed collections of five common prairie species were obtained from four remnant prairie populations (one large and three small). A common garden experiment was conducted in the spring and summer of 2005, where individuals from these populations were germinated and transplanted into a restoration site. Plants were monitored throughout the growing season for growth, vegetative reproduction, and flowering. Above ground biomass was harvested following senescence to assess total growth. Single factor ANOVAs of biomass data among collection sites showed significance in three of five species (Dalea purpurea, Eryngium yuccifolium, and Parthenium integrifolium). However these analyses did not show a consistent pattern with remnant size. Single ANOVAs of biomass data between species showed significance in three study sites. Survival did not vary with collection sites for any species. This suggests that plant performance is unpredictable with remnant size. These results support the use of seed collections from several sites, even if a large contiguous site is available, as the best choice for restoration practice.
404. Tropical cloud forest bird response to edge effects Author: Keiller Kyle, Purdue University Keywords: edge effects, cloud forest, endemism, birds Area: Population Ecology
Birds are one of the most studied taxa in the tropics, yet we have not determined the mechanisms that explain the decline in avian species richness on tropical forest edges. Few studies have measured variables that influence species’ sensitivity to edge habitat. My project will document responses by the avian community of Monteverde, Costa Rica to forest edge. In addition, I will measure environmental variables along the edge to interior forest gradient to look for relationships between the avian community and the changing habitat. Elevational range and dietary categories for avian species will be determined as possible mechanisms for sensitivity to edge. My study will add to our understanding of the effectiveness of preserved forest in providing usable habitat to birds and offer a mechanistic explanation for forest edge sensitivity.
405. Do habitat edges and a coflowering species facilitate pollination of a plant with unrewarding flowers? Author: James Crants, University of Michigan Keywords: deceit pollination, facilitation, edge effects, pollen limitation, self compatibility Area: Population Ecology
Mayapple (Podophyllum peltatum L.), an herb in eastern North American forests, depends on outcross pollination by insects for sexual reproduction. However, its flowers lack nectar, and it consequently has very low visitation rates and reproductive success. Visitation for unrewarding entomophilous species may be promoted by proximity to rewarding plants, and similar facilitation effects may apply to anything that increases the local abundance of pollinators. In this study, I tested whether pollination for mayapple was facilitated by wild geranium (Geranium maculatum L.), a co-flowering, nectar-producing species, and by forest edges, habitats that may be favorable to both pollinators and co-flowering species. I also tested mayapples for self-compatibility, and whether environmental factors explained variations in reproductive success among mayapples.
Pollination greatly limited fruit and seed production in all five study sites. Self-compatible colonies were detected in only one of the sites. Among the self-compatible colonies, selfed flowers had depressed fruit and seed set compared to outcrossed flowers, suggesting that inbreeding depression reduces the benefits of self-compatibility in this species. I found weak evidence for facilitation of pollination by wild geranium based on seed set per flower, and none based on fruit set per flower or seed set per fruit. There was no evidence for facilitation of pollination by forest edges. No measured environmental variable affected mayapple’s reproductive success. Facilitation may occur on larger scales than those used in this study, or it may be more likely in communities with higher densities of rewarding flowers than my study sites.
406. The evolution of life history strategies in swallowtail butterflies: the timing of diapause Authors: Ashley Amodeo, Lauren Hoffmann, Ashley Maire, and Bryan Helm, DePauw University Keywords: life history strategies, trade-offs, body size Area: Population Ecology or Population Genetics (Michele: Phy. and Evolution?)
Diapause in insects is a physiological state characterized by low metabolic activity and increased resistance to environmental conditions inhospitable to growth. In swallowtail butterflies in central Indiana diapause is facultative and occurs during the pupal stage in response to environmental cues assessed during the larval stage. In theory, the timing of entry into diapause should be under strong stabilizing selection, with the optimal time of entry being one generation before the end of the growing season. We estimated the timing of diapause in the field in six species of swallowtail butterflies with different generation lengths. We found significant differences among species in diapause timing, but no relationship between generation length and time of entry into diapause. We also estimated the costs of entering diapause too early by measuring pupal weight loss as a function of time in diapause.
407. The evolution of life history strategies in swallowtail butterflies: the trade-off between body-size and larval growth period Authors: Bryan Helm, Ashley Maire, Ashley Amodeo, and Lauren Hoffman, DePauw University Keywords: life history strategies, trade-offs, body size Area: Population Ecology or Population Genetics (Michele: Phy. and Evolution?)
A common assumption in evolutionary ecology is that in species with determinate growth large body size is gained at the expense of a longer period of growth. This study examined this assumption in five species of swallowtail butterflies by measuring the duration of the larval stage and body mass at pupation in individuals reared in the field from early to late summer. We found no support for the assumption that faster growth is traded for smaller size. Both individual growth rates and final body sizes were quite variable and, in one species, growth rate slows dramatically as the summer progress, possibly as result of increases in secondary compounds in the larval food plant.
408. Intra-specific differences in Penstemon floral morphology Author: Rebecca Tonietto, Chicago Botanical Garden Keywords: Penstemon, floral morphology, pollination Area: Population Ecology
Pollination syndromes have driven speciation within Penstemon. We studied three syndromes; hummingbird, bumblebee, and generalist, represented by three Penstemon species in the Great Basin. In general, hummingbird pollinated P. rostriflorus flowers are narrow-throated and red. Bumblebee pollinated pachyphyllus have blue, bulbous, widely open-throated flowers. P. deustus have white, open-throated flowers which are smaller and narrower than pachyphullis, and are pollinated by a variety of insect genera. All three species are widely distributed; yet each are found in extremely isolated populations (over 500 km apart) with potentially variable pollinator communities. We found significant floral morphological differences within each of the three species by site. Key variable traits include corolla length and width, and the angle the lip creates relative to the corolla tube.
501. Stability of abundance and distribution in tropical cloud forest birds Author: Matthew R. Gasner, Purdue University Keywords: birds, cloud forest, stability, distribution, climate change Area: Climate Change and Conservation
Extinction risks are increasing for tropical montane birds as they often have restricted geographical ranges, occur in low abundances, are at risk to high levels of deforestation, and are now threatened by global warming. Saving species from this growing list of pressures requires detailed information about their distributions, abundance, population dynamics, and expected population viability so that future conservation efforts can focus on designing effective management strategies. With hope of assisting future conservation decisions, I intend to study the montane avian community within the primary forests of Monteverde, Costa Rica, which contain a large proportion of Central American endemic bird species. By using replicated point-count surveys spread between 1400-1800m during two local breeding seasons (May-July, 2006-2007), I will be able to examine a number of the individual and population-level aspects of the local bird community. 1) I will produce the first population-density estimates for many bird species endemic to the highlands of Costa Rica and Panama. 2) By combining my data with point-count surveys from 2001 and 2003, I can begin to estimate population dynamics and/or identify community-wide distributional shifts possibly caused by climate change, as it has been recently linked by Pounds and colleagues (1999) to the up-slope shifts of individual species in the Monteverde area. 3) Many of my points overlap sites surveyed to species level by local plant experts, thus providing an opportunity to perform a correspondence analysis between bird species’ distributions and local abundances to the same information for plant species.
502. Reproductive and stress physiology of Canada lynx: implications for reintroduction success Author: Kerry Fanson, Nadja Wielebnowski, and Jeff Lucas, Purdue University and Brookfield Zoo Keywords: conservation physiology, reintroductions, Canada lynx Area: Climate Change and Conservation
The number of threatened and endangered species in the world continues to rise every year. However, for many of these species, we lack basic information about their physiology and behavior that could help us implement more effective conservation practices. This project seeks to describe the basic reproductive and stress physiology of Canada lynx, a federally threatened species. Using the non-invasive technique of fecal hormone analysis, we monitored hormone expression in captive lynx throughout the breeding season. We analyzed fecal concentrations of estradiol, progesterone, testosterone, and glucocorticoid metabolites. I will present results from one successful breeding pair, four unsuccessful breeding pairs, and seven singly-housed lynx (four females and three males). In the future, the information obtained from this project can be compared to hormonal data obtained from reintroduced Canada lynx in Colorado to gain a better understanding of how the reintroduction process impacts lynx physiology.
503. Are abnormal sperm adaptive? An examination of sperm competition and species abundance Author: Keefe Reuther, Saint Louis University Keywords: sperm, competition, conservation, sexual selection Area: Climate Change and Conservation
Selection can drive male sperm to evolve adaptive morphologies. Differences in sperm size, motility, longevity, and fertility can affect the reproductive success of males in functionally polyandrous species. Baker and Bellis (1988) proposed the controversial “kamikaze” sperm hypothesis, which postulates that abnormal sperm could have an adaptive function. Namely, such sperm cannot fertilize ova, but they can eject, block, or kill the viable sperm of competitors. Opposition to this hypothesis states that abnormal sperm are meiotic errors resulting from inbreeding depression and do not serve an adaptive function. Conservation genetics commonly uses the proportion of abnormal sperm as an indicator of vulnerable species that are undergoing serious population declines or have experienced bottlenecks. I searched the literature for data regarding the proportion of abnormal sperm in species in order to test these conflicting hypotheses. Using ANOVA and Tukey post-hoc analyses, I tested the effect of species abundance and mating system (a proxy measure for sperm competition) on proportion of abnormal sperm. Species abundance and sperm competition both negatively affected the proportion of abnormal sperm (p = 0.06, p = 0.12). Separate analyses of mammals elicited similar results. This review shows no evidence that abnormal sperm serve an adaptive function in sperm competition and supports the use of sperm abnormalities as a marker for inbreeding depression. However, due to small sample size and the wide variety of taxa studied, this review does not preclude the adaptive function of abnormal sperm in all taxa. Further studies are necessary that examine specific taxonomic groups in depth, controlling for the numerous confounding variables (e.g. other modes of sexual selection, cryptic matings, natural history differences) before Baker and Bellis’ (1988) hypothesis is falsified or supported.
601. The phylogenetic significance of the gill arches of cypriniform fishes (Actinopterygii: Ostariophysi) Authors: Kevin W. Conway and Richard L. Mayden, Saint Louis University Keywords: phylogeny, morphology, gill arches, classification, Cypriniformes Area: Phylogenetics and Evolution
Monophyly of the Order Cypriniformes is based largely on the presence of modified pharyngeal teeth on the fifth gill arch. Though this character is widely used in systematic treaties of the group, little attention has been paid to the remaining gill arches. In this study the systematic significance of 31 characters derived from the gill arches of cypriniform fishes is explored. Four characters support the monophyly of the Order Cypriniformes: (1) absence of pharyngobranchial uncinate processes; (2) absence of toothplate associated with basibranchials 1-3; (3) absence of toothplates associated with pharyngobranchials; (4) teeth on ceratobranchial 5 ankylosed to the bone. The families Gyrinocheilidae, Catostomidae and Balitoridae were also recovered as monophyletic but gill arch characters alone are insufficient to characterize the families Cyprinidae and Cobitidae as currently recognized. The results presented here conflict with the current classification of the Order Cypriniformes where the Superfamily Cyprinoidea (cyprinids) is sister to the Cobitoidea (non-cyprinid cypriniforms). In the present study the families Cyprinidae+Cobitidae+Balitoridae form a monophyletic group separate from Catostomidae and Gyrinocheilidae. Members of the cyprinid subfamily Psilorhynchinae are more closely related to a clade composed of cobitids and balitorids than to other cyprinids. A unique feature of the gill filaments of balitorids (base of gill filaments ossified) is reported for the first time.
602. Phylogenetic studies of Cucumis and Cucumella (Melothrieae, Cucurbitaceae) using nuclear ribosomal and chloroplast gene sequences Author: Amanuel Ghebretinsae, Saint Louis University Keywords: molecular phylogenetics, Cuphea, Lytheraceae Area: Phylogenetics and Evolution
Cucumis is a well-known member of the Cucurbitaceae and comprises ca. 32 species including several of major economic importance (e.g. cucumbers, melons, the West Indian Gherkin, the Kiwano). Two subgenera are recognized, differing in geographical distribution and chromosome number. Subgenus Melo (30 spp., n = 12) is native to Africa whereas subgenus Cucumis (4 spp., n = 7) is indigenous to Asia. However, the recent discovery of an Asian species (C. hystrix) with basic chromosome number n = 12 has challenged the classification, suggesting a possible bridge between the subgenera. Furthermore, derivation of the subgenera is under debate. The taxonomic relationship of species of Cucumis and the closely related genus Cucumella is also poorly understood. Cucumella comprises 11 species with a distribution that mirrors that of Cucumis. Long considered synonymous, Cucumella was placed as a distinct genus in 1990. Morphologically, Cucumella is separated from Cucumis by a single morphological character: anther shape. A number of molecular studies at various taxonomic levels have included species of Cucumis, but none have addressed generic-wide phylogenetic relationships and none have included any species of Cucumella. In the current study, sequences of nuclear ribosomal DNA from the internal transcribed spacer (ITS) region and a trnS-G intergeneric spacer of chloroplast DNA were used to explore relationships within and between the two genera. The results reported here support the separation of Cucumis and Cucumella as distinct genera. Within the genus Cucumis, however, the Asian species, forming a clade, were found embedded within the African clade, contradicting with the existing morphological infrageneric classification. Within subgenus Melo, two sections and two series were found to be monophyletic. Our findings also suggest that the origin of Cucumis is in Africa, supporting Sing’s (1990) cytological hypothesis. Almost all domesticated species of Cucumis are susceptible to a number of devastating fungal, bacterial and insect diseases. A number of biotechnological studies are underway to find beneficial genes from wild relatives that have better resistance to such diseases. Our study presents the candidate species and relevant information to make informed decisions in this regard. Future directions for this project will be discussed.
603. Phylogenetic relationships within the myco-heterotrophic Hexalectris Raf. (Orchidaceae) Authors: Aaron H. Kennedy and Linda E. Watson, Miami University (of Ohio) Keywords: phylogenetics, systematics, Orchidaceae, evolution, myco-heterotrophy Area: Phylogenetics and Evolution
Seven species and two subspecies are recognized in the largely North American orchid genus Hexalectris. Its species are terrestrial, fully myco-heterotrophic, and have variously colored erect leafless stems that represent the aboveground portion of the plant. Flowers are variable in terms of their number, color, lateral sepal shape, petal shape, anther color, and number of lamellae. Its center of diversity is the mountainous regions of southern Texas and northern Mexico. All seven species are native to Mexico with five of these also occurring in the United States. Additionally, H. brevicaulis is endemic to Mexico and H. parviflora is native to Mexico and Guatemala. The most widespread taxon, H. spicata var. spicata, ranges from northern Mexico, north to Missouri, east to the Atlantic coast, and south into central Florida. The phylogenetic relationships among Hexalectris taxa are unclear. Previous authors (FNA included) have speculated based on floral morphology, that H. spicata s.l., H. revoluta s.l., H. nitida, and H. parviflora form a complex of closely related species. Additionally, the cleistogamous variety of H. spicata, var. arizonica, has been suggested to be a hybrid taxon formed from H. spicata var. spicata and H. nitida or H. revoluta. The phylogenetic placement of the remaining two species, H. warnockii and H. brevicaulis remains unclear. To resolve phylogenetic relationships among Hexalectris species and to test its monophyly, we are utilizing multiple DNA sequences including the 5’trnL – 3’trnL intergenic spacer region of the chloroplast genome and the internal transcribed spacers (ITS) of nrDNA.
604. The convergent evolution of a polyphenism: the effects of cyclic adenosine monophosphate on pupal color polyphenism in the swallowtail buttefly Papilio polyxenes Authors: Marisa Yochum and Lauren Rakes, DePauw University Keywords: cAMP, pupal color, polyphenism Area: None given (Michele: Phylogenetics and Evolution)
Polyphenism is the ability of a single organism to respond to environmental cues by producing distinctly different phenotypes. In many Lepidoptera, pupal color is polyphenic. Typically, green pupae are produced when pupation occurs on a green pupation site and brown pupae are produced when pupation is on a brown site. The proximate mechanisms regulating pupal color are believed to have evolved independently and in parallel within Lepidoptera, with the release of the same peptide hormone (PMRF) resulting in green pupae in the nymphalid lineage, and brown pupae in the papilionid lineage. The mediation of signaling with cyclic nucleotides acting as second messengers is typical of peptide hormones and in the nymphalid butterfly Inachis io administration of a cAMP analog mimics the effects of PMRF by causing pupae to be green. We show that cAMP analog has the opposite effect in the papilionid Papilio polyxenes. These results are consistent with the hypothesis that events in the control of pupal color “downstream” from cAMP signaling have evolved independently in the two groups of Lepidoptera.
605. Evolution of ornamentation and flower color in the orchid genus Thelymitra Author: Courtney Finch, Saint Louis University Keywords: Thelymitra, Orchidaceae, mitra, blue flowers Area: Phylogenetics and Evolution
Blue is an uncommon color in nature, even in flowering plants. The orchid family, Orchidaceae, with an estimated 25,000 species is no exception. In the approximate 800 described genera of orchids, only about five contain species with blue flowers. One of these genera is Thelymitra with about 75% of the 60-70 species have flowers that are brilliant shades of blue. Although blue is predominant, Thelymitra flowers can be pink, purple, white, yellow or multi-colored. Species within the genus also possess a unique staminodal complex called a mitra. These structures vary in degree of ornamentation, shape and color and have some have been described as resembling pom pons or rabbit ears. Despite these striking characteristics, Thelymitra remains largely understudied. Taxonomic relationships within the genus have long been debated and the only hypothesis of relationships is based on morphological characters. In this study, I use two non-coding chloroplast DNA markers that have been shown to increase phylogenetic resolution at low taxonomic levels to reconstruct a phylogeny of 17 species of Thelymitra that exhibit color and mitra variation. The mitra character and flower color are mapped onto the phylogeny to examine the evolution of ornamentation and the color blue in the genus.
606. Genetic analysis of diversity within the river sturgeons of central Asia (Acipenseridae: Pseudoscaphirhynchus) Authors: Jeremy C. Hunn, Jeffery M. Ray, Robert M. Wood, Bernard R. Kuhajda, and Richard L. Mayden, Saint Louis University and University of Alabama Keywords: conservation, population genetics Area: Phylogenetics and Evolution
All species within the sturgeon genus Pseudoscaphirhynchus (P. kaufmanni, P. hermanni, and P. fedtschenkoi) are endangered or critically endangered. The first two species occur in the Amu Darya River and the third is from the Syr Darya River, all within the Aral Sea Basin in Central Asia. While morphological differences distinguish between all three recognized species, the intraspecific variation within each of these species suggests that this genus is actually composed of seven species. In this study, we concentrate on the two species from the Amu Darya River by using multiple microsatellite markers to identify differences between these species and their variants and test the concordance between the morphological and genetic data. Analysis of thirteen microsatellite provides additional information on the variation within and among these species. Accurate species delineation is essential to meaningful conservation and recovery efforts of endangered taxa.
607. A comparison of pollinator efficiency in two sister Silene species Author: Alexandra Rohde, University of Evansville Keywords: pollinator efficiency, Silene virginica, Silene stellata, floral syndromes Area: Phylogenetics and Evolution
As sessile organisms, plants rely on outside vectors such as water, air, and animals to transfer male gametes to female receptors. An important consideration in the evolution of floral syndromes is the efficiency of the pollinators for a given population of plants, as floral syndromes are currently defined as being a suite of floral characteristics symptomatic of a flower pollinated by a given class of pollinators. Using data collected by myself on Silene virginica (bird-syndrome flower) in 2005 and data collected on Silene stellata (moth-syndrome flower) by Reynolds, Dudash, and Fenster in 2004, I compared the pollinator efficiency of hummingbirds on S. virginica, nocturnal pollinators (moths, mostly Noctuidae) on S. stellata, and diurnal pollinators (bees) on S. stellata. Efficiency was determined as pollen deposited divided by pollen removed.
Hummingbirds are the most efficient pollinators of the three groups, with an efficiency of 2.07%. Nocturnal S. stellata pollinators had an efficiency of 0.73%. Diurnal S. stellata pollinators had an efficiency of 0.25%. This supports my belief that S. virginica evolved to a bird-syndrome flower from a bee- or moth-syndrome flower because of selection pressure from hummingbirds’ greater efficiency as pollinators. While these two species evolved to be better adapted to their most important pollinators, even after generations of adaptive evolution, hummingbirds remain the most efficient pollinators.
608. Host race formation in southern Rhagoletis pomonella populations Author: Thomas H. Powell, University of Notre Dame Keywords: none Area: Phylogenetics and Evolution
Rhagoletis pomonella is a model species for studying sympatric speciation through host shifting, potentially a common mode of speciation for phytophagous insects. Most of the research on R. pomonella evolution has focused on a recent host shift from the ancestral hawthorn host to apples after their introduction into North America over 150 years ago. The adaptations allowing for this host shift have been shown to involve both olfactory recognition of host fruit volatiles and pupal diapause patterns corresponding to host plant fruiting times. The pre-zygotic and post-zygotic barriers to gene flow established in this shift have resulted in very limited gene flow between the apple and hawthorn populations.
In the southeastern United States, R. pomonella is known to infest several different species of hawthorn trees, providing more potential cases for incipient speciation due to host plant shifts. Differences in fruit odors and fruiting times between hawthorn species may have presented the same opportunity for ecological divergence as observed in the more northern hawthorn to apple shift. This study aims to investigate the possibility of host race formation in southern hawthorns through experiments examining odor response behavior, developmental timing, and population genetics. I will be collecting flies from 5 different hawthorn species and conducting both field and laboratory experiments to determine whether ecological divergence has occurred.
609. Notung 2.1: a program for evaluating and optimizing gene duplications and losses in gene trees Author: Benjamin Vernot, Carnegie Mellon University Keywords: reconciliation, phylogeny reconstruction, gene duplication Area: Phylogenetics and Evolution
Gene tree analysis is a powerful approach to studying the history and timing of duplications in the evolution of a gene family. However, if a gene tree is unrooted or contains edges with low bootstrap values, more than one interpretation is possible. Furthermore, for genome scale studies, a large number of trees must be considered. Software tools to automate this analysis and to manage, score and display alternate interpretations are required. We present Notung, an exploratory analysis tool to evaluate alternate hypotheses in terms of the number of gene duplications and losses that occurred. Notung can root unrooted gene trees to minimize duplication and loss, can reconcile gene and species trees for identification of gene duplications and losses, and can rearrange gene trees in areas of low sequence support. Notung uses a graphical user interface for viewing alternate hypotheses, and can also be run from the command line for automated analysis of many trees.
Notung will be of interest to scientists who wish to bring macroevolutionary considerations to bear on gene tree construction; evolutionary biologists studying the history of a gene family; and experimental biologists interested in incorporating evolutionary insights into questions of function and structure.
Notung is implemented in Java (requires version 1.4.2 or higher), and runs on Windows, Linux and Mac OS X. The Notung program, full documentation, worked examples, and sample scripts for automated analyses are available for free download from the Notung website at: http://www.cs.cmu.edu/~durand/Notung.
701. Seasonality of parasites in house sparrows (Passer domesticus) of Coles County, IL Author: Tiffany Gibson, Eastern Illinois University Keywords: coccidia, avian malaria, seasonality, stress Area: Midwest Topics
Parasitism often shows seasonal variation. This may be due to host densities, host stress levels, or parasite transmission strategies. This study follows the prevalence of malaria, vector-borne blood parasites, and coccidia, non-vectored gut parasites, in house sparrows (Passer domesticus) over the course of two years. The role of transmission strategies and stresses such as winter (when vectors are absent) and breeding (when vectors are present) on parasitism levels were evaluated. Both of these parasites are capable of causing disease and have been reported in non-native non-migrant house sparrows from Illinois, but there is little information on the seasonality of these infections. This study also compares current infection parameters to historical records of 8.7% prevalence of avian malaria in house sparrows in Coles County, Illinois (Fox 1968). Sporulated oocysts from fecal floatation were identified and scored on a semi-quantitative scale. Blood smears were stained and a total of 10,000 red blood cells (RBC) were scanned per slide for the presence of apicomplexans. Preliminary results indicate that Illinois house sparrows are commonly infected with coccidia (Isospora sp.), but avian malaria has not been observed in these birds. High prevalence and intensity of coccidia was found during the winter. This may be a function of stress or high localized host density in roost and feeding sites. Knowledge of seasonal parasite burdens in these birds is necessary to investigate the potential of dense populations of non-natives to serve as parasite sources to native species, especially those of special conservation concern
702. Movements and habitat selection of raccoons in a fragmented Illinois landscape Authors: Erin E. Barding and Thomas A. Nelson, University of Kentucky and Eastern Illinois University Keywords: habitat selection, habitat fragmentation, edge effects, raccoons, mesopredator, nest predation Area: Midwest Topics
Much of the natural habitat of the Midwestern U.S. has been converted to agricultural use, while remaining natural areas are typically highly fragmented, creating large amounts of edge habitat. Research on nesting songbirds has identified edge-related increases in rates of nest predation to be a main cause of reduced reproductive success in fragmented landscapes. Raccoons (Procyon lotor) have been identified as one of the most significant nest predators, and more research is needed to provide a better understanding of how these mesopredators utilize habitat in an agricultural matrix. The specific objectives of my study were to: (1) evaluate the movements and home ranges of raccoons during the avian nesting and brood rearing season, (2) describe patterns of habitat selection at three spatial scales during the summer, and (3) suggest appropriate management strategies to reduce the impact of raccoons on nesting birds. Trapping and radio-telemetry were conducted on Richardson Wildlife Foundation (RWF) property in Lee Co., IL during May-August of 2002 and 2003. Home ranges were calculated or 21 raccoons tracked on RWF; the mean MCP (minimum convex polygon) was 47.5 ha (range=7-108, sd=27.8), the mean 95% kernel home range was 60.5 ha (range=9-117, sd=32.7), and the mean 50% kernel home range was 8.13 ha (range=1-25, sd=5.6). Compositional analysis determined that raccoons on RWF selected forest edge at all three spatial scales. The proportions of habitats within raccoon home ranges contained more forest edge than proportions of habitat types available in the study area. Within their home ranges, raccoons selected forest edges and wetlands while avoiding grasslands and cropland during nightly movements. Raccoons on RWF followed linear landscape features such as fencerows and trails during nightly movements, so decreasing the amount of man-made edge habitat may decrease the impact of raccoons and other mesopredators on ground nesting birds since these animals may predate nests incidentally while foraging for other food.
X01. The effect of pappus removal on seed germination in North American dandelions (Taraxacum officinale; Asteraceae) Authors: Alison N. Maye and Matthew H. Collier, Wittenburg University Keywords: seed germination, Taraxacum officinale, pappus Area: Seed Germination
Fruit produced by apomictic (agamospermous) North American dandelions consists of an achene and an awn-like modification of the calyx called a pappus, which is known to facilitate seed dispersal. Based on observations in our previous work concerning dandelion seed germination (i.e., appearance of the radicle), we hypothesized that pappus removal reduces seed germination in dandelions. To test this hypothesis, seeds from twenty different dandelion plants both with (N = 200) and without (N = 200) a pappus were placed in plastic tubs (34.4 cm x 21.4 cm x 11.5 cm) lined with Whatman paper (N = 20, one tub per plant) and allowed to germinate under a light bank (24 hour photoperiod) for a two-week period. Total numbers of germinating seeds both with and without a pappus were counted in each tub and totaled across tubs. Time to germination (number of days) over the two-week investigation was also recorded. Significant differences in mean total seed germination within tubs (P < 0.0001), total germination across tubs (P < 0.0001; total germinated with pappus = 91/200, total germinated without pappus = 52/200), and mean time to germination (P < 0.0001; time to germination with pappus = 3.92 days, time to germination without pappus = 5.10 days) were detected. These results suggest that seed germination in dandelions is reduced and time to germination is increased if the pappus is removed. We intend to replicate our study using different dandelion populations and also determine whether genetic differences in seed germination exist across different dandelion clonal lineages.
X02. A comparison of two molecular markers for gender determination in beaver (Castor canadensis). Authors: Joanne C. Crawford, Zhiwei Liu, and Thomas A. Nelson, Eastern Illinois University Keywords: beaver, sex-determination, genetics, Castor canadensis Area: Techniques
Studies of population structure, dispersal and mating behavior require accurate sex identification. In beavers, sex identification is often a problem due to the lack of sexual dimorphism. The traditional method of sex identification in beavers by external palpation can be inaccurate. The objectives of this study were to: (1) compare the efficiency and accuracy of two genetic methods using different molecular markers for determining sex, and (2) use genetic methods to assess the accuracy of the palpation method used in field studies. We compared the zinc-finger DNA method to the Y-chromosome specific SRY method using DNA extracted from tissues of 25 beavers from central Illinois. Of the 25 animals studied, sex had been previously identified for 12 by palpation and for 13 by dissection following removal trapping. The zinc-finger region is found on both sex chromosomes, but fragments are longer on the Y-chromosome. The SRY method amplifies the SRY region on the Y-chromosome for sex identification and amplification of the cytochrome b gene on the mitochondrion verifies the presence of DNA. The results of our experiments showed that sex determination using the SRY method was less ambiguous and more efficient than the zinc-finger method, and this may be due to a number of factors. Sex was correctly assigned by palpation for 9 of 12 (75%) animals. These results highlight the need for and the usefulness of genetic methods for confirming the sex of beavers in field studies.
X03. Phenotypic plasticity in the communication system of Neoconocephalus triops (Orthoptera: Tettigoniidae) Authors: Oliver M. Beckers and Johannes Schul, University of Missouri - Columbia Keywords: communication, phenotypic plasticity, temperature, call recognition Area: Animal Communication
Neoconocephalus triops in northern Florida has two seasonal generations per year. The male calls differ between generations in two temporal features. The winter call is continuous and has a significant slower double-pulse rate than the summer call, which is structured in verses. The different calls are induced by the respective photoperiodical regime of each generation. In this study we investigate whether the female recognition system shares the phenotypic plasticity of the male calls.
Females of both summer and winter generation were tested in behavioral experiments using a single stimulus playback design. The crucial parameter used for call recognition was double pulse rate, largely independent of any other temporal parameter tested. Stimuli with call structures of the winter generation (continuous) and the summer generation (verse) were equally attractive to females of both generations. The tuning of the call recognition system did not differ between generations at the tested ambient temperatures. It was tuned to double pulse rates specific to the winter call at 20°C and to double pulse rates specific to the summer call at 25°C. The recognition system was not matched with the winter call at 25°C and the summer call at 20°C.
Our results show that the recognition system does not share the plasticity of the calls. These findings suggest that the phenotypic plasticity in the male calls might have evolved to match the recognition system in a seasonally varying mating environment. This evolutionary scenario will be investigated further by testing populations with only one mating call.
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