Life Sciences Commons^™

Colour And Odour Drive Fruit Selection And Seed Dispersal By Mouse Lemurs, Kim Valenta, Ryan J. Burke, Sarah A. Styler, Derek A. Jackson, Amanda D. Melin, Shawn M. Lehman

Dartmouth Scholarship

Animals and fruiting plants are involved in a complex set of interactions, with animals relying on fruiting trees as food resources, and fruiting trees relying on animals for seed dispersal. This interdependence shapes fruit signals such as colour and odour, to increase fruit detectability, and animal sensory systems, such as colour vision and olfaction to facilitate food identification and selection. Despite the ecological and evolutionary importance of plant-animal interactions for shaping animal sensory adaptations and plant characteristics, the details of the relationship are poorly understood. Here we examine the role of fruit chromaticity, luminance and odour on seed dispersal by …

Cold Tolerance Of The Eastern Subterranean Termite, Reticulitermes Flavipes (Isoptera: Rhinotermitidae), In Ontario., Matthew W. Clarke, Graham J. Thompson, Brent J Sinclair

Biology Publications

We characterized the cold tolerance of natural populations of the Eastern subterranean termite (Reticulitermes flavipes (Kollar) [Isoptera, Rhinotermitidae]) in southwestern Ontario, Canada. We measured cold tolerance in workers from six colonies of termites established from Pelee Island in Lake Erie, and Point Pelee National Park. The mean critical thermal minimum, at which termites entered chill coma, ranged from 8.1 to 5.7°C. Mean supercooling points (SCP, the temperature at which individuals freeze) ranged from -4 to -4.6°C, and did not differ significantly between colonies, nor was SCP dependent on body size. Individuals survived brief exposure to low temperatures, as long as …

A Comprehensive And Integrative Reconstruction Of Evolutionary History For Anomura (Crustacea: Decapoda)., Heather D Bracken-Grissom, Maren E Cannon, Patricia Cabezas, Rodney M Feldmann, Carrie E Schweitzer, Shane T Ahyong, Darryl L Felder, Rafael Lemaitre, Keith A Crandall

Computational Biology Institute

BACKGROUND: The infraorder Anomura has long captivated the attention of evolutionary biologists due to its impressive morphological diversity and ecological adaptations. To date, 2500 extant species have been described but phylogenetic relationships at high taxonomic levels remain unresolved. Here, we reconstruct the evolutionary history-phylogeny, divergence times, character evolution and diversification-of this speciose clade. For this purpose, we sequenced two mitochondrial (16S and 12S) and three nuclear (H3, 18S and 28S) markers for 19 of the 20 extant families, using traditional Sanger and next-generation 454 sequencing methods. Molecular data were combined with 156 morphological characters in order to estimate the largest …

Tree Climbing And Human Evolution, Vivek V. Venkataraman, Thomas S. Kraft, Nathaniel J. Dominy

Dartmouth Scholarship

Paleoanthropologists have long argued—often contentiously—about the climbing abilities of early hominins and whether a foot adapted to terrestrial bipedalism constrained regular access to trees. However, some modern humans climb tall trees routinely in pursuit of honey, fruit, and game, often without the aid of tools or support systems. Mortality and morbidity associated with facultative arboreality is expected to favor behaviors and anatomies that facilitate safe and efficient climbing. Here we show that Twa hunter–gatherers use extraordinary ankle dorsiflexion (>45°) during climbing, similar to the degree observed in wild chimpanzees. Although we did not detect a skeletal signature of dorsiflexion …

Aspm And The Evolution Of Cerebral Cortical Size In A Community Of New World Monkeys, Fernando A. Villanea, George H. Perry, Gustavo A. Gutiérrez-Espeleta, Nathaniel J. Dominy

Dartmouth Scholarship

The ASPM (abnormal spindle-like microcephaly associated) gene has been proposed as a major determinant of cerebral cortical size among primates, including humans. Yet the specific functions of ASPM and its connection to human intelligence remain controversial. This debate is limited in part by a taxonomic focus on Old World monkeys and apes. Here we expand the comparative context of ASPM sequence analyses with a study of New World monkeys, a radiation of primates in which enlarged brain size has evolved in parallel in spider monkeys (genus Ateles) and capuchins (genus Cebus). The primate community of Costa Rica is perhaps a …

Rapid Inversion: Running Animals And Robots Swing Like A Pendulum Under Ledges, Jean-Michel Mongeau, Brian Mcrae, Ardian Jusufi, Paul Birkmeyer, Aaron M. Hoover, Ronald Fearing, Robert J. Full

Aaron M. Hoover

Escaping from predators often demands that animals rapidly negotiate complex environments. The smallest animals attain relatively fast speeds with high frequency leg cycling, wing flapping or body undulations, but absolute speeds are slow compared to larger animals. Instead, small animals benefit from the advantages of enhanced maneuverability in part due to scaling. Here, we report a novel behavior in small, legged runners that may facilitate their escape by disappearance from predators. We video recorded cockroaches and geckos rapidly running up an incline toward a ledge, digitized their motion and created a simple model to generalize the behavior. Both species ran …

Two Boundaries Separate Borrelia Burgdorferi Populations In North America, Gabriele Margos, Jean I. Tsao, Santiago Castillo-Ramirez, Yvette A. Girard, Anne G. Hoen

Dartmouth Scholarship

Understanding the spread of infectious diseases is crucial for implementing effective control measures. For this, it is important to obtain information on the contemporary population structure of a disease agent and to infer the evolutionary processes that may have shaped it. Here, we investigate on a continental scale the population structure of Borrelia burgdorferi, the causative agent of Lyme borreliosis (LB), a tick-borne disease, in North America. We test the hypothesis that the observed d population structure is congruent with recent population expansions and that these were preceded by bottlenecks mostly likely caused by the near extirpation in the 1900s …

Fecal Near Infrared Spectroscopy To Discriminate Physiological Status In Giant Pandas., Erin E. Wiedower, Andrew J. Kouba, Carrie K. Vance, Rachel L. Hansen, Jerry W. Stuth, Douglas R. Tolleson

College of Agriculture & Life Sciences Publications and Scholarship

Giant panda (Ailuropoda melanoleuca) monitoring and research often require accurate estimates of population size and density. However, obtaining these estimates has been challenging. Innovative technologies, such as fecal near infrared reflectance spectroscopy (FNIRS), may be used to differentiate between sex, age class, and reproductive status as has been shown for several other species. The objective of this study was to determine if FNIRS could be similarly used for giant panda physiological discriminations. Based on samples from captive animals in four U.S. zoos, FNIRS calibrations correctly identified 78% of samples from adult males, 81% from adult females, 85% from adults, 89% …

Wild Justice Redux: What We Know About Social Justice In Animals And Why It Matters, Jessica Pierce, Marc Bekoff

Ethology Collection

Social justice in animals is beginning to attract interest in a broad range of academic disciplines. Justice is an important area of study because it may help explain social dynamics among individuals living in tightly- knit groups, as well as social interactions among individuals who only occasionally meet. In this paper, we provide an overview of what is currently known about social justice in animals and offer an agenda for further research. We provide working definitions of key terms, outline some central research questions, and explore some of the challenges of studying social justice in animals, as well as the …

Mapping Migratory Bird Prevalence Using Remote Sensing Data Fusion, Anu Swatantran, Ralph Dubayah, Scott Goetz, Michelle Hofton, Matthew G. Betts, Mindy Sun, Marc Simard, Richard Holmes

Dartmouth Scholarship

Background: Improved maps of species distributions are important for effective management of wildlife under increasing anthropogenic pressures. Recent advances in lidar and radar remote sensing have shown considerable potential for mapping forest structure and habitat characteristics across landscapes. However, their relative efficacies and integrated use in habitat mapping remain largely unexplored. We evaluated the use of lidar, radar and multispectral remote sensing data in predicting multi-year bird detections or prevalence for 8 migratory songbird species in the unfragmented temperate deciduous forests of New Hampshire, USA.

Methodology and Principal Findings: A set of 104 predictor variables describing vegetation vertical structure and …

Predator Mediated Selection And The Impact Of Developmental Stage On Viability In Wood Frog Tadpoles (Rana Sylvatica), Ryan Calsbeek, Shawn Kuchta

Dartmouth Scholarship

Complex life histories require adaptation of a single organism for multiple ecological niches. Transitions between life stages, however, may expose individuals to an increased risk of mortality, as the process of metamorphosis typically includes developmental stages that function relatively poorly in both the pre- and post-metamorphic habitat. We studied predator-mediated selection on tadpoles of the wood frog, Rana sylvatica, to identify this hypothesized period of differential predation risk and estimate its ontogenetic onset. We reared tadpoles in replicated mesocosms in the presence of the larval odonate Anax junius, a known tadpole predator.

Episodic Radiations In The Fly Tree Of Life, Brian M. Wiegmann, Michelle D. Trautwein, Isaac S. Winkler, Norman B. Barr, Jung-Wook Kim, Christine Lambkin, Matthew Bertone, Brian Cassel, Keith Bayless, Alysha Heimberg

Dartmouth Scholarship

Flies are one of four superradiations of insects (along with beetles, wasps, and moths) that account for the majority of animal life on Earth. Diptera includes species known for their ubiquity (Musca domestica house fly), their role as pests (Anopheles gambiae malaria mosquito), and their value as model organisms across the biological sciences (Drosophila melanogaster). A resolved phylogeny for flies provides a framework for genomic, developmental, and evolutionary studies by facilitating comparisons across model organisms, yet recent research has suggested that fly relationships have been obscured by multiple episodes of rapid diversification. We provide a phylogenomic …

Micrornas Reveal The Interrelationships Of Hagfish, Lampreys, And Gnathostomes And The Nature Of The Ancestral Vertebrate, Alysha M. Heimberg, Richard Cowper-Sal{Middle Dot}Lari, Marie Semon, Philip C. J. Donoghue, Kevin J. Peterson

Dartmouth Scholarship

Hagfish and lampreys are the only living representatives of the jawless vertebrates (agnathans), and compared with jawed vertebrates (gnathostomes), they provide insight into the embryology, genomics, and body plan of the ancestral vertebrate. However, this insight has been obscured by controversy over their interrelationships. Morphological cladistic analyses have identified lampreys and gnathostomes as closest relatives, whereas molecular phylogenetic studies recover a monophyletic Cyclostomata (hagfish and lampreys as closest relatives). Here, we show through deep sequencing of small RNA libraries, coupled with genomic surveys, that Cyclostomata is monophyletic: hagfish and lampreys share 4 unique microRNA families, 15 unique paralogues of more …

Microarray Analysis Of A Salamander Hopeful Monster Reveals Transcriptional Signatures Of Paedomorphic Brain Development, Robert B. Page, Meredith A. Boley, Jeramiah J. Smith, Srikrishna Putta, Stephen R. Voss

Biology Faculty Publications

BACKGROUND: The Mexican axolotl (Ambystoma mexicanum) is considered a hopeful monster because it exhibits an adaptive and derived mode of development - paedomorphosis - that has evolved rapidly and independently among tiger salamanders. Unlike related tiger salamanders that undergo metamorphosis, axolotls retain larval morphological traits into adulthood and thus present an adult body plan that differs dramatically from the ancestral (metamorphic) form. The basis of paedomorphic development was investigated by comparing temporal patterns of gene transcription between axolotl and tiger salamander larvae (Ambystoma tigrinum tigrinum) that typically undergo a metamorphosis.

RESULTS: Transcript abundances from whole brain and pituitary were estimated …

Manipulating Testosterone To Assess Links Between Behavior, Morphology, And Performance In The Brown Anole Anolis Sagrei, Robert M. Cox, Derek S. Stenquist, Justin P. Henningsen, Ryan Calsbeek

Dartmouth Scholarship

Survival and reproductive success are determined by the complex interplay between behavior, physiology, morphology, and performance. When optimal trait combinations along these various phenotypic axes differ between sexes or across seasons, regulatory mechanisms such as sex steroids can often facilitate sex‐specific and/or seasonal trait expression. In this study, we used surgical castration and replacement of exogenous testosterone in adult male brown anoles (Anolis sagrei) to simultaneously examine the effects of testosterone on a suite of morphological (dewlap area, body size), physiological (immune function), behavioral (dewlap, head bob, and push‐up displays), and performance (stamina, sprint speed, bite force) traits. …

Rapid Fixation Of Non-Native Alleles Revealed By Genome-Wide Snp Analysis Of Hybrid Tiger Salamanders, Benjamin M. Fitzpatrick, Jarrett R. Johnson, D. Kevin Kump, H. Bradley Shaffer, Jeramiah J. Smith, S. Randal Voss

Biology Faculty Publications

BACKGROUND: Hybrid zones represent valuable opportunities to observe evolution in systems that are unusually dynamic and where the potential for the origin of novelty and rapid adaptation co-occur with the potential for dysfunction. Recently initiated hybrid zones are particularly exciting evolutionary experiments because ongoing natural selection on novel genetic combinations can be studied in ecological time. Moreover, when hybrid zones involve native and introduced species, complex genetic patterns present important challenges for conservation policy. To assess variation of admixture dynamics, we scored a large panel of markers in five wild hybrid populations formed when Barred Tiger Salamanders were introduced into …

The Tempo And Mode Of Three‐Dimensional Morphological Evolution In Male Reproductive Structures, Mark A. Mcpeek, Li Shen, John Z. Torrey, Hany Farid

Dartmouth Scholarship

Various evolutionary forces may shape the evolution of traits that influence the mating decisions of males and females. Phe- notypic traits that males and females use to judge the species identify of potential mates should evolve in a punctuated fashion, changing significantly at the time of speciation but changing little between speciation events. In contrast, traits experiencing sexual selection or sexually antagonistic interactions are generally expected to change continuously over time because of the directional selection pressures imposed on one sex by the actions of the other. To test these hy- potheses, we used spherical harmonic representations of the shapes …

Micrornas And The Advent Of Vertebrate Morphological Complexity, Alysha M. Heimberg, Lorenzo F. Sempere, Vanessa N. Moy, Phillip C. J. Donoghue, Kevin J. Peterson

Dartmouth Scholarship

The causal basis of vertebrate complexity has been sought in genome duplication events (GDEs) that occurred during the emergence of vertebrates, but evidence beyond coincidence is wanting. MicroRNAs (miRNAs) have recently been identified as a viable causal factor in increasing organismal complexity through the action of these ≈22-nt noncoding RNAs in regulating gene expression. Because miRNAs are continuously being added to animalian genomes, and, once integrated into a gene regulatory network, are strongly conserved in primary sequence and rarely secondarily lost, their evolutionary history can be accurately reconstructed. Here, using a combination of Northern analyses and genomic searches, we show …

Predation And Cathemerality. Comparing The Impact Of Predators On The Activity Patterns Of Lemurids And Ceboids., Ian C. Colquhoun

Anthropology Publications

The removal, or absence, of predatory species could be a contributing proximate factor to the rise of primate cathemerality. But predators themselves can also be cathemeral, so cathemerality could well be an evolutionary stable strategy. From a comparative perspective, it appears that the effect of predatory species cannot provide a unitary explanation for cathemerality. Varying distributions and population densities of predators, especially raptors, may be key factors in owl monkey (Aotus) cathemerality, but temperature and lunar cycle variation have also been implicated. In Madagascar, while raptors are potential predators of lemur species, the cathemerality of Eulemur species coincides with that …

The Ethics Of Wildlife Control In Humanized Landscapes, John Hadidian, Camilla H. Fox, William S. Lynn

Ecology Collection

The 21st century is witness to an unprecedented and rapid growth of human settlements, from urban centers to wilderness vacation resorts. Concurrent with this has been the growing tolerance and acceptance of many wild animals and humans for one another. This has created an expanding ‘zone’ of human-animal contacts, some number of which invariably result in conflicts. While the vast majority of our interactions with wild animals are undoubtedly benign, it is the conflict between wildlife and people that draws particularly close attention from the public. Animals viewed as vertebrate “pests” range from the small to the large, the timid …

Origin Of The Eumetazoa: Testing Ecological Predictions Of Molecular Clocks Against The Proterozoic Fossil Record, Kevin J. Peterson, Nicholas J. Butterfield

Dartmouth Scholarship

Molecular clocks have the potential to shed light on the timing of early metazoan divergences, but differing algorithms and calibration points yield conspicuously discordant results. We argue here that competing molecular clock hypotheses should be testable in the fossil record, on the principle that fundamentally new grades of animal organization will have ecosystem-wide impacts. Using a set of seven nuclear-encoded protein sequences, we demonstrate the paraphyly of Porifera and calculate sponge/eumetazoan and cnidarian/bilaterian divergence times by using both distance [minimum evolution (ME)] and maximum likelihood (ML) molecular clocks; ME brackets the appearance of Eumetazoa between 634 and 604 Ma, whereas …

Estimating Metazoan Divergence Times With A Molecular Clock, Kevin J. Peterson, Jessica B. Lyons, Kristin S. Nowak, Carter M. Takacs, Matthew J. Wargo, Mark A. Mcpeek

Dartmouth Scholarship

Accurately dating when the first bilaterally symmetrical animals arose is crucial to our understanding of early animal evolution. The earliest unequivocally bilaterian fossils are 555 million years old. In contrast, molecular-clock analyses calibrated by using the fossil record of vertebrates estimate that vertebrates split from dipterans (Drosophila) 900 million years ago (Ma). Nonetheless, comparative genomic analyses suggest that a significant rate difference exists between vertebrates and dipterans, because the percentage difference between the genomes of mosquito and fly is greater than between fish and mouse, even though the vertebrate divergence is almost twice that of the dipteran. Here we show …

Sightings Of Moose, Deer, And Bears On Roads In Northern Ontario, D. Fraser

Anthropogenics and Population Decline Collection

No abstract provided.