«Strengthening the Nation through Diversity, Innovation & Leadership in STEM San Antonio,Texas · October 3-6, 2013 Get Connected! Connect with the ...»
1 Dramatic changes in ocean temperatures are likely to alter marine ecosystems in the near future. As such, there is a large effort to understand how sea creatures will respond to their shifting environments. The globally invasive European green crab, Carcinus maenas, has been closely monitored because of its ecological and economic impacts but is a useful species with which to study thermal adaptation. Previous physiological work has concluded that different populations within the species may be locally adapted to their thermal environments. To better understand this adaptation, this project examines genes that appear to be under selection between sites with different thermal conditions. By sampling crabs from 5 populations within the North American invasive range, we identified 279 single nucleotide polymorphisms (SNPs) in 203 contiguous sequences as potentially under selection from a total of 8,718 SNPs identified by a previous study. This list was further narrowed to 9 sequences, each with at least 3 SNPs and annotations with functional descriptions in the GenBank database. These 9 sequences closely matched genes involved in cell respiration, immune response, protein destruction, muscle tissue construction, solute transportation, and circulatory control during stress. To verify these patterns, we directly sequenced several genes of interest in an expanded sample set.
INTRASPECIFIC RESOURCE COMPETITION WITHIN A TROPICAL BIRD SPECIES (RAMPHOCELUSCOSTARICENSIS) Autumn Chong1, Wendy Kuntz2, Jessie Knowlton3.
University of Hawaii at Hilo, Kamuela, HI, 2University of Hawai’i Kapiolani Community College, Honolulu, HI, 1
Organization for Tropical Studies, Las Cruces, CR.3
Food availability can drive competition and dominance aggression among individuals. In the Neotropics, fruit resources are distributed patchily so competition among frugivores can be intense. Even within a single species, there may be competition and dominance hierarchies among different age and sex classes. Many tropical bird species are monomorphic in plumage, but the Cherrie’s Tanager (Ramphocelus costaricensis) shows strong sexual dichromatism and presents an opportunity to examine intraspecific competition because sex and age classes can be distinguished by plumage. Initial observations led us to hypothesize that among R. costraricensis, there is a dominance hierarchy at food sources in which males displace females and juveniles because of their size. To test our hypothesis, we set up 10 banana feeding stations throughout the Wilson Botanic Garden of Las Cruces, Costa Rica. Feeding stations were set up near trees that provided refuge from predators. Each time an R. costaricensis visited the feeding station, we recorded its sex and age class based on plumage and its food intake. For intraspecific interactions we recorded
81 UNDERGRADUATE POSTER ABSTRACTS
distance between individuals, agonistic behaviors, displacement, and the time until displacement. Fierce competition for food arises between individuals even if they are the same species. In frugivores, intraspecific competition may make it difficult to get an accurate assessment of the amount of food resources needed to sustain a particular species.
Additionally, intraspecific competition may result in fine scale resource portioning between age and sex classes.
EXPLORING HOW FLIGHT MORPHOLOGY VARIES WITH DEGREE OF HABITAT DISTURBANCE IN
NEOTROPICAL BATSPookela Stillman Reyes1, Alice Hughes2.
Kapiolani Community College, Honolulu, HI, 2Centre of Conservation and Biodiversity, Xishuangbanna Tropical 1 Botanical Garden (CAS), Xishuangbanna, CN.
Bats make up the second most specious groups of mammals, and display a diverse range of characteristics which enable them to live in almost any habitat type. Within Costa Rica, bats make-up around half the known mammal species, with at least 108 known species. However bats are closely adapted to their habitat type and their morphology and echolocation characteristics vary considerably depending on the habitat type. Here, we explore how bat morphometrics vary with the degree of clutter in the environment; how parameters of both the wing (aspect ratio, wing-loading, etc.) and call vary with the degree of disturbance in the environment; and what characteristics may enable some species to inhabit many different habitat types, whereas others may be limited to a narrower selection.
The study was conducted in Las Cruces Biological Reserve in Costa Rica, using mistnets to explore how the community varied in areas with different degrees of clutter and disturbance. Once captured, numerous parameters for each individual bat were taken before each bat was released. Our analysis found that species that were found across environment types had the ability to alter wing-shape, whereas those in either open or closed environments had wing morphometrics that might be expected with the degree of clutter in the environment.
LEAF ANATOMICAL TRAITS LINKED TO DROUGHT TOLERANCE IN THE LOS ANGELES URBAN ECOSYSTEM
University of California Los Angeles, Los Angeles, CA.
Tree canopy cover in urban areas has economic, social, and environmental benefits, but in order to maintain green space, we need to take into consideration how much water is needed to irrigate trees in urban areas such as Los Angeles. Los Angeles is an arid region characterized by environmental stresses including low precipitation, low relative humidity, and high summer temperature. Thus, it is necessary to understand relationships between leaf functional traits and water use and drought tolerance. In this study we address how leaf traits such as leaf thickness, leaf dry-mass per area, stomatal density and size, and venation architecture contribute to drought tolerance inferred through measurements of osmotic potential at turgor loss point. We hypothesize that across species these functional traits will correlate with stress tolerance. To test this hypothesis we will sample leaves from 50 common urban tree species and measure osmotic potential at turgor loss point, leaf thickness, area and dry mass, stomatal density and individual dimensions, and major and minor vein length per area. The results will give us species specific differences in stress tolerance strategies and provide a better mechanistic understanding of leaf resistance to hydraulic decline in street trees.
DIVERSITY AND EVOLUTION OF INNATE IMMUNITY GENES IN SEA URCHINSEric Curiel, Grant Pogson.
University of California, Santa Cruz, Santa Cruz, CA.
In all invertebrates, the innate immune system is the sole line of defense against pathogens. Unlike the well-studied major histocompatibility complex (MHC) genes in vertebrates, very little is known about the evolution of genes functioning in the innate immune system in any marine invertebrate. In sea urchins, there are over 600 genes associated with 3 super families of immune-related genes: toll-like receptors (TLRs), NACHT domain–leucinerich repeat proteins (NLRs), and scavenger receptor cysteine-rich proteins (SRCRs). Our goal is to study the diversification of these 3 gene families in the complete genomes of 9 species of sea urchins belonging to the family Strongylocentrotidae. Using the genome sequence of the purple sea urchin as a reference, we will examine the rates of expansion and contraction of these gene families and test for the action of natural selection caused by the dynamic
THE EFFECTS OF NATIVE VS. NONNATIVE LEAF LITTER ON MACROINVERTEBRATE COMMUNITIESMelanie Keliipuleole1, Justin Montemarano2.
Kapiolani Community College, Honolulu, HI, 2Armstrong Atlantic State University, Savannah, GA.
1 Introduced species are becoming a concern for numerous ecological communities around the world. With the possibility of becoming invasive, nonnative species greatly disrupt ecosystem function and native communities. This study investigates the effects that nonnative leaf litter may have on decomposition dynamics within a premontane, tropical wet forest. In particular, detritivore community composition and leaf-litter mass loss are compared within litterbags containing leaves from a native riparian tree (Miconia appendiculata) and an invasive bamboo (Phyllostachys makinoi). Research plots were selected along the Río Java at the Las Cruces Biological Station in Costa Rica. Two 5-gram bags of each species and a mixture of the 2 species will be placed at 5 different sites along the river and subsamples will be collected after 10 and 20 d instream to investigate macroinvertebrate colonization.
Chemical characterization of stream water (e.g., dissolved oxygen, pH, temperature, nitrate tests, and phosphate tests) will be conducted daily. We predict that the native leaf litter will have a greater decomposition rate and a more diverse community of macroinvertebrates due to coevolutionary relationships with native leaf litter. Findings from this study will also better our understanding of how detritivore communities in tropical wet forest streams function in the breakdown of different types of leaf litter.
THE BOVIDAE OF GLADYSVALE CAVE AND THE ENVIRONMENTAL IMPLICATIONS IN THE CONTEXT OF
OTHER FOSSIL-BEARING LOCALITIES IN THE NORTHERN TRANSVAAL REGION, SOUTH AFRICABogart Marquez II, Tesla Monson, Leslea Hlusko.
University of California, Berkeley, Berkeley, CA.
In 1947, Charles Camp and Frank Peabody from the Museum of Paleontology at the University of California, Berkeley (UCMP), undertook a South African expedition in search of fossils. The sites explored were largely in the northern Transvaal and Cape Province regions and date roughly from the early Pleistocene to the Holocene. This work yielded more than 2,500 vertebrate fossils, including at least 43 species. Some of the sites, notably Taung, were known to have yielded fossil material of early human ancestors, including the Australopithecus africanus type-specimen found in 1924. At the close of the expedition, the material was shipped to the UCMP, where a significant amount of material from this expedition remained to be catalogued and more specifically identified to taxonomic group. We undertook this endeavor to further the knowledge available on South African fauna of the Pleistocene. Our specific focus was to study and identify the Bovidae from Gladysvale Cave, a cave in the northern Transvaal, making identifications to tribe when possible. The bovidae assemblage from the cave consisted of 230 specimens that had to be analyzed, identified, and systematically sorted. An analysis of tribe percentages and their context provides insight into the paleoecology of the region. Our method for fossil identification involved a comparative analysis with modern bovid skeletal specimens from the University of California, Berkeley, Museum of Vertebrate Zoology, and from published literature. Our results will be presented in the context of reconstructing the paleoecology of this locality and the evolution of South African environments.
IMPACTS OF INDIVIDUAL VARIATION IN INFECTIOUSNESS ON DISEASE PERSISTENCEAnna Naranjo1, Michael Buhnerkempe2, Jamie Lloyd-Smith2, Sebastian Schreiber1.
University of California, Davis, Davis, CA, 2University of California, Los Angeles, Los Angeles, CA.
1 Mathematical models of infectious diseases can provide insights into the interplay between epidemiological and population processes such as individual infectiousness and pathogen persistence. Evidence from previous research shows that individuals in a population exhibit different degrees of infectiousness; some individuals do not infect others, while others are highly infectious. However, it is not known how this variability affects the persistence of pathogen circulation within populations or how this persistence depends on population size. Here, we explore variability in individual infectiousness using a stochastic, discrete time model. By incorporating different distributions for infectiousness, we can characterize the relationship between pathogen persistence, individual variation in infectiousness, and population size. We expect that in smaller populations, with greater variation among individuals,
83 UNDERGRADUATE POSTER ABSTRACTS
the disease will exhibit greater fluctuations, and therefore will not persist as long. This variation can also affect the frequency of fade-outs and reintroduction of disease. However, for large populations, the variation in individual infectiousness will have less impact, and persistence times should look similar to models that use the same value of infectivity for the entire population. By comparing the new model that incorporates individual variability to the homogeneous model, we can identify when individual variation has a significant impact on disease persistence.
ECOLOGICAL SORTING AND EVOLUTIONARY SPECIALIZATION IN CECROPIA–AZTECA INTERACTIONSAmanda Maria Santos1, Cynthia Sagers2.
Northern Marianas College, Saipan, MP, 2University of Arkansas, Fayetteville, AR.