Marine predators as sentinels of environmental change in Arctic ecosystems
March 4th 12:30-1:30pm ET
Arctic ecosystems are undergoing rapid change, and long-lived top predators are considered sentinels of the impacts of climate change on marine ecosystems. Beaufort Sea beluga whales (Delphinapterus leucas) and thick-billed murres (Uria lomvia) in northern Hudson Bay have experienced long-term shifts in prey species and declines in inferred growth rates, believed to be the result of environmental changes. In partnership with Inuvialuit communities, we examined inter-annual variation and environmental factors affecting prey, body condition, and physiology of Beaufort Sea beluga whales. Body condition of belugas was positively correlated with myoglobin, hemoglobin concentrations, and % hematocrit, with lower total body O2 stores in whales with lower body condition. The relationship between body condition and O2 storage capacity in whales may represent a positive feedback mechanism, in which environmental changes resulting in decreased body condition impair foraging ability. To examine the impacts of climate- induced prey shifts on the energetics of seabirds, heart rate was examined as a proxy for O2 consumption in murres and black-legged kittiwakes (Rissa tridactyla), and were calibrated with GPS-accelerometers to classify behaviours and activity rate. Finally, we examined the effects of Arctic warming on murre physiology. In response to increasing temperatures, murres exhibited limited heat tolerance and low ability to dissipate heat, with one of the lowest evaporative cooling efficiencies recorded in birds. These results highlight the various impacts of climate change on marine predators and their broader implications on Arctic ecosystems.
Daniel Gillis (University of Toronto)
Citizen science reveals songbird spring migration arrival time is advancing more for efficient fliers
February 25th 12:30-1:30pm ET
Shifting phenology in response to climate change has been documented for many taxa worldwide. Several migratory bird species are arriving at their breeding regions earlier, which can lead to trophic and climatic mismatches. This trend towards earlier arrival times contains considerable variation and the mechanisms behind differences in migration shifts are not clear. We hypothesized that greater flight efficiency may be associated with larger shifts, as better fliers may have more flexibility to respond to changing conditions during migration. We applied an updated modelling approach towards analyzing 18 years of eBird citizen science data to generate estimates of the mean arrival date for 29 common passerines migrating to northeast North America. We compared temporal shifts in mean arrival date with morphology parameters associated with flight efficiency and migratory distance. Our research highlights how traits can influence the ability of species to adjust phenology in response to climate change. Identifying possible targets for climate change-induced selection will facilitate conservation efforts for targeting species with traits that will be a detriment to novel climatic conditions. Increasing citizen science involvement provides the opportunity to test novel modelling techniques for generating geographically broad, long-term analyses of important ecological trends.
Dr. Lindsay Miles (University of Toronto)
Gene flow and genetic drift in urban environments
February 18th 12:30-1:30pm ET
We currently live in the Anthropocene, where humans have a drastic impact on ecosystems. One of the ways that we alter ecosystems is through urbanization, the building of cities. This new urban ecosystem has the potential to influence evolution for the many organisms living in or near cities. I study the non-adaptive evolutionary signatures of urbanization, how gene flow and genetic drift are impacted by urbanization. There are two competing models that predict how urbanization changes non-adaptive evolution, the urban fragmentation model and the urban facilitation model. While many organisms appear to experience the urban fragmentation model, which suggests overall negative impacts of urbanization, there are some species that experience urban facilitation. My research aims to predict which organisms are most likely experience fragmentation vs facilitation.
Dr. Geetha Thimmegowda (National Centre for Biological Sciences)
Theeffect of air pollution on insects
Feb 11th 12:30-1:30pm ET
While the impact of air pollution on human health is well studied, mechanistic impacts of air pollution on wild systems, including those providing essential ecosystem services, are largely unknown, but directly impact our health and well-being. India is the world’s largest fruit producer, second-most populous country, and contains 9 of the world’s 10 most polluted cities. Here, we sampled Giant Asian honey bees, Apis dorsata, at locations with varying air pollution levels in Bangalore, India. We observed significant correlations between increased respirable suspended particulate matter (RSPM) deposition and changes in bee survival, flower visitation, heart rate, hemocyte levels, and expression of genes related to lipid metabolism, stress, and immunity. Lab-reared Drosophila melanogaster exposed to these same sites also exhibited similar molecular and physiological differences. Our study offers a quantitative analysis on the current impacts of air pollution on insects and indicates the urgency for more nonhuman studies to accurately assess the effects of pollution on our natural world.
René S. Shahmohamadloo from Guelph University
The toxicology of microcystins in freshwater organisms of the Great Lakes
Feb 4th 12:30-1:30pm ET
Harmful algal blooms dominated by Microcystis aeruginosa are causing ecological and socio-economic disturbances to freshwater ecosystems, in particular the Great Lakes, through the production of microcystin toxins, which can cause disease-related effects in freshwater organisms. This presentation investigates the mechanisms of microcystin toxicity to freshwater organisms of the Great Lakes and assesses the human health risks from consuming fish exposed to cyanobacterial blooms. Using state-of-the-art, quantitative techniques (e.g., targeted and nontargeted LC-QTOF MS to measure microcystins in tissues and proteomics) I further describe, for the first time, toxicological impacts from microcystin exposure to pelagic and benthic invertebrates, as well as fish species humans enjoy including in their diets.
Dr. Kate Laskowski
“You are unique, just like everyone else: What clonal fish can tell us about behavioral individuality”
January 28th 12:30 – 1:30 pm ET
Individual behavioral variation is ubiquitous across the animal kingdom. Explaining the continued generation and maintenance of such variation is a fundamental goal in behavioral and evolutionary ecology. Our research tests key predictions drawn from theoretical models about how social interactions can drive the emergence of consistent individual behavioral variation. This work has shown that competitive interactions, especially in early life, can play a particularly important role in shaping long-term individual behavioral decisions. Now, using the clonal Amazon molly and an innovative high-resolution tracking system we are following the behavioral development of individual fish from birth in, up to now, unprecedented detail. This allows us to pinpoint exactly when and in response to which cues individual behavioral variation emerges. Most recently, we have shown that individual behavioral variation appears almost immediately after birth and then continues to diverge over ontogeny. Our results highlight that in order to fully explain the presence of individual behavioral variation we need a comprehensive conceptual framework that explicitly accounts for the developmental process.
Dr. Manas Samant
Investigating the interaction between inter-locus and intra-locus sexual conflict using hemiclonal analysis in Drosophila melanogaster
January 21st 12:30 – 1:30 pm ET
Divergence in the evolutionary interests of males and females leads to sexual conflict. Traditionally, sexual conflict has been classified into two types: inter-locus sexual conflict (IeSC) and intra-locus sexual conflict (IaSC). IeSC is modeled as a conflict over outcomes of intersexual reproductive interactions mediated by loci that are sex-limited in their effects. IaSC is thought to be a product of selection acting in opposite directions in the two sexes on traits with a common underlying genetic basis. While in their canonical formalisms IaSC and IeSC are mutually exclusive, there is growing support for the idea that the two may interact. Empirical evidence for such interactions, however, is limited. We investigated the interaction between IeSC and IaSC in Drosophila melanogaster. Using hemiclonal analysis, we sampled 39 hemigenomes from a laboratory-adapted population of D. melanogaster. We measured the contribution of each hemigenome to adult male and female fitness at three different intensities of IeSC obtained by varying the operational sex-ratio. Subsequently, we estimated the intensity of IaSC at each sex-ratio by calculating the intersexual genetic correlation for fitness and the proportion of sexually antagonistic fitness-variation. Additionally, we also measured a suit of male and female traits associated with sexual conflict in D. melanogaster. Our results indicate a statistically non-significant trend that suggests that increasing the strength of IeSC ameliorates IaSC in the population, a pattern that might be driven by positive genetic correlations between female resistance traits and male fitness.
Dr. Blake Jones
Bennington CollegeUnderstanding complex sociality: Field-based and meta-analytic approaches
Jan 14th 12:30 – 1:30 pm ET
Welcome back! We kick off the Winter EEB Seminar Series next week with Dr. Blake Jonesfrom Bennington College, hosted by the Bonier lab. Dr. Jones studies the underlying mechanisms of development, sociality, learning, and memory in free-living animals. His research integrates theories and techniques from climate-science, ecology, physiology, genetics, and cognitive neuroscience. Tune in next Thursday at 12:30 pm to hear about his work on manakins, social hierarchies, and mate choice copying! ABSTRACT Complex sociality has evolved across the animal kingdom. As such, biologists as early as Darwin have focused on the ultimate aspects of complex social behaviors, such as cooperation and social learning. More recently, integrative approaches in biology have led to a growing understanding of the proximate mechanisms of sociality in a number of diverse taxa. Here, I highlight a few examples of field-based and meta-analytical approaches to better understand how complex social behaviors are mediated and modulated. First, social classes are a common feature of cooperative animal societies, but what determines an individual’s place within the social hierarchy? My colleagues and I investigated this question in the lance-tailed manakin (Chiroxiphia lanceolata), a cooperative bird species with a complex social hierarchy. We found that glucocorticoids, hormones associated with the physiological stress response, positively correlated with and predicted current and future social status. Likewise, we found a similar predictive link between future social status and the dynamics of telomeres, repetitive sequences of non-coding DNA at the ends of chromosomes. Second, female mate choice is a critical component of sexual selection and can be influenced by social information. Female mate choice copying occurs when one female copies the apparent mate choice of another female and has been documented in numerous taxa. Though this social phenomenon has the potential to influence patterns of sexual selection, how widespread is it? And, what are the individual and environmental factors that modulate its effect? We used a meta-analytical approach to discover that mate-choice copying is exhibited across taxa and is strongly influenced by factors both intrinsic and extrinsic to the individual.
Blake’s work aims to uncover the genetic and physiological underpinnings of complex sociality, cognition, and development in free-living animals. He uses integrative and comparative approaches in the lab and the field to address questions at the forefront of organismal biology. His work is highly collaborative, involving researchers and undergraduates from throughout the US as well as Brazil and Australia. Blake’s work has been funded by multiple National Science Foundation awards, The Nature Conservancy, the Society for Integrative and Comparative Biology, and the American Ornithological Society. He routinely publishes in peer-reviewed, international scientific journals, including Animal Behaviour, Frontiers in Ecology and Evolution, General and Comparative Endocrinology, Hormones and Behavior, and Oecologia. Blake’s teaching style focuses on critical thinking and first-hand experience in the lab and the field. He draws on his diverse experience in research, conservation, field biology, veterinary medicine, art, music, and photography to make biology easily accessible. B.S., James Madison University; Ph.D., University of Memphis; Visiting Research Scholar, Curtin University (Perth, Australia); Postdoctoral Scholar, Florida State University. Blake joined Bennington College in 2020.
The choice of “who to mate with” has profound consequences for organisms and populations alike, determining not only phenotypes and trait expression within an individual, but the ecology, genetics, and evolutionary trajectories of populations and species. In plants, mate choice falls into a few main categories of reproductive modes, including preferential mating with oneself (self-fertilization), avoiding mating (asexual reproduction), or avoiding mating with different species. Mating habits thus shape patterns of genomic variation, gene flow, and speciation and are key to the astounding biological diversity that we see in the world. My research integrates field ecology, population genetics, and theory to address two main questions: 1) What are the ecological and genomic consequences of mate choice? and 2) How does mate choice influence speciation? I will present two stories of mate choice in wild plant populations. First, I explore the impacts of asexuality, hybridization, and self-fertilization on the evolution of sex in the North American wildflower Boechera. Second, I discuss a population genetic model that predicts the breakdown of reinforcement in wild maize and teosinte due to sexual conflict between a female mating barrier allele and a male compatibility allele. The interplay between these two phenomena highlights the tension between the costs and benefits of hybridization. My work shows how plant diversity is shaped by the influence of mating habits on both trait evolution and speciation, and future work will continue to explore the micro- and macroevolutionary consequences of mate choice.
Climate change and land use change impacts on pollinators
Presented by Peter Soroye
Dec 3rd 12:30 – 1:30 PM ET
(email for Zoom link)
Pollinators, including bumblebees (Bombus), are declining in range size and abundance across their ranges across North America and Europe, linked in large part to rapid recent climate change and changes in human land use. Niche theory and physiology suggest that species’ physiological limits might define whether they persist in some areas and may help to inform predictions on climate change effects. Using a spatially explicit index for calculating species’ exposure to thermal and precipitation limits across their ranges and a comprehensive occurrence dataset of North American and European bumblebee species, we test whether a species’ or communities’ proximity to thermal or precipitation tolerance limits predicts local extinction, colonization, occupancy, and species richness change, and how these climate change-related biodiversity responses interact with changing land use.
Peter Soroye is a PhD Student in Biology working with Prof Jeremy Kerr at the University of Ottawa. Peter is a conservation biologist studying the impacts of climate change and land use change on biodiversity across the globe, with the goal of informing conservation management and policy to find more effective ways of protecting species and reversing declines of biodiversity. In February 2020, Peter published the first chapter of his PhD research in the journal Science, which was focused on a novel mechanism for predicting climate change related extinction risk in bumblebees.