EEB Summer Break

The EEB seminar series is taking a break over the summer. We will return in the Fall with our first seminar taking place on September 18th.

In the meantime, if you have suggestions for speakers for the fall and winter terms, please do not hesitate to email us.  Scheduling will be done in a largely first-come, first-served fashion so the best way to get your speaker in is to let us know as soon as possible.

 

Thank you – and see you in the Fall,

EEB Committee

EEB Seminar: May 15th

Lukas Schärer will talk on

Of fluorescent sperm in a transparent flatworm: using functional genomics to study sex in a simultaneous hermaphrodite

at 12:30 in the EEB lounge (BioSciences 4338)

Lukas Schärer and Dita Vizoso are a husband and wife research team at the University of Basel in Switzerland. Currently, research in the lab tries to understand why sexual reproduction is so widespread throughout the animal kingdom, especially in unconventional (and understudied) groups like hermaphroditic animals. Much of their work is done with hermaphroditic flatworms that have both male and female genitalia. These worms are about the size of a comma and mate readily under a microscope, making them ideal for understanding the evolution of sexual reproduction. Lukas and Dita’s research has provided tremendous insight into the evolution of sperm morphologies, allocation of resources to male and female reproductive functions (sex allocation), sexual conflict, mating behavior, and taxonomy of the flatworm genus Macrostomum. For incredible videos (verging on x-rated) of Macrostomum, check out: http://evolution.unibas.ch/scharer/research/current_research/macrostomum_mating_behaviour.html

Everyone is welcome to attend
Coffee and treats available at the seminar

EEB Seminar: May 1st

Julia Duszczyszyn will talk on

Precious sperm and nurturing females: reversing stereotypes about fertilization biology

at 12:30 in the EEB lounge (BioSciences 4338)

When we think about sexual selection, we are drawn to colourful examples of male combat, colouration, courtship dances, songs, nuptial gifts, and the list goes on and on. We all know what happens before mating, but what happens next? In the last few decades, recognition of the complexity and diversity of sexually-selected processes occurring after mating has grown. This post-copulatory sexual selection takes two major forms: sperm competition and cryptic female choice. My research has made use of a long-term evolution experiment that has produced a model phylogeny of Drosophila melanogaster lines with wildly different life history strategies to study the evolution of sperm and sperm-female interactions. I introduced GFP-labeled sperm to these populations to study the transfer of sperm and subsequent interaction between sperm and the female reproductive tract in vivo. My results suggest that sperm, testes, and the female reproductive tract can evolve rapidly in this species, and that sperm are both costly to produce and costly to maintain in the female storage organs. This work contributes to an ever-deeper understanding of the tradeoffs underlying post-copulatory sexual selection and sperm storage. I see beautiful complexity in the coevolution between male and female in this hidden arena of interaction.

Julia Duszczyszyn is a Master’s student at Queen’s University working with Adam Chippendale. Broadly, Julia is interested in sperm morphology. Her research examines trade-offs between sperm development (e.g., size, performance, quantity) and the time required to reach sexual maturity in fruit flies. Recent advances in sperm studies make it possible to watch drosophila sperm in real time; these sperm glow red or green and bumble their way down the female reproductive track like a Christmas parade. Julia has spent countless hours carefully dissecting recently inseminated female fruit flies and video taping sperm in action to quantify aspects of sperm morphology and performance.

Everyone is welcome to attend
Coffee and treats available at the seminar

EEB Seminar: April 17th

Dr. Shannon McCauley will talk on

Assessing the interactions between local and regional processes in freshwater metacommunities

at 12:30 in the EEB lounge (BioSciences 4338)

The structure of ecological communities can be affected by both local processes occurring within habitats and by regional processes including the connectivity between habitats, shaped by both landscape structure and species dispersal. I will discuss how habitat connectivity and differences in species’ dispersal behaviour affect the distributions of dragonfly species across a landscape and how dispersal behaviour can shape species ranges across much larger (continental) scales. Local and regional processes do not, however, exist in isolation from each other and can interact in ways that have implications for populations and communities. I will also discuss results from work in dragonflies and other semi-aquatic insects that provide insights into some of the ways these interactions may develop including context-dependent dispersal and individual variation in dispersal behaviour. While we are just beginning to understand the connections between local and regional processes and how they modify each other, recognizing the linkages between processes at these different scales is yielding insights missed by a focus on processes only occurring at a single scale.

a marked dragonfly

Dr. Shannon McCauley is an Assistant Professor at the University of Toronto, Missassauga. She is a freshwater ecologist interested in the processes that shape ecological communities across different spatial scales. For example, how do predator-prey interactions shape local communities? How do dispersal abilities of organisms shape community composition and species distributions? And how do these processes (predation and dispersal) interact to influence community structure? Shannon addresses these question using a diversity of approaches from extensive spatial and temporal surveys of aquatic communities to experiments that range from mesocosm-level to landscape-level manipulations.

Everyone is welcome to attend
Coffee and treats available at the seminar

EEB Seminar: April 10th

Dr. Hugh Henry will talk on

Production and nutrient cycling in temperate ecosystems: how winter climate matters

at 12:30 in the EEB lounge (BioSciences 4338)

Climate exerts strong controls over plant growth and nutrient cycling, but the mechanisms underlying climate responses have mainly been studied over the growing season. However, winter processes can also play an important role in driving ecosystem responses, and northern temperate regions in particular are sensitive to variability in winter climate. I examined projections of soil freezing responses to climate change using a variety of modeling, observational and hindcasting approaches. Overall, despite a general pattern of a decreased numbers of days of frozen soil and decreased numbers of days with snow on the ground, projected responses of soil freezing dynamics to climate change have been regional in nature, and many northern temperate regions are expected experience an increased number of soil freeze thaw cycles as a result of reduced snow cover. The responses of plants and nitrogen dynamics to changes in soil freezing are sensitive to the timing, frequency, length and severity of soil freezing. I have conducted a range of laboratory, mesocosm and field experiments to examine the important thresholds inherent in these responses, and to assess how freezing damage may interact with increases in atmospheric N deposition over the next century.

one of Hugh's warming experiments

Dr. Hugh Henry is an associate professor at Western University. He completed his Master’s at Queen’s (with Lonnie Aarssen) and his PhD at the University of Toronto (with Robert Jefferies). Hugh is broadly interested in nutrient cycling, plant physiology, and global climate change, and how these factors affect plants and micro organisms at the individual, community and ecosystem level. Current research in the Henry lab examines nitrogen (N) uptake during winter (when N uptake is assumed to be unimportant) and during late fall and early spring when freeze-thaw cycles and water runoff create dynamic transitions in the nitrogen cycle. To explore these ideas, Hugh uses large-scale experiments that simulate climate warming, laboratory techniques, and theoretical modeling. His work has taken place in sunny California, snowy Ontario, and salt marshes in the Arctic.

Everyone is welcome to attend
Coffee and treats available at the seminar

EEB Seminar: April 3rd

Kristina Arseneau will talk on

Acidification & Climate Warming: Understanding Biological Recovery in Multiple Stressor Environments

at 12:30 in the EEB lounge (BioSciences 4338)

Lakes in North America and Europe are undergoing chemical recovery from acidification and there is consequently a pressing research need to define recovery targets for acidified sites. Researchers attempting to designate such targets are hampered by two issues: 1) a lack of long-term monitoring data; and, 2) the influence of multiple stressors on recovering lakes. This project highlights how pairing a regional reference site approach with paleolimnological techniques can overcome these two problems. Using a set of stringent selection criteria, 31 minimally-disturbed reference lakes protected from acidification, eutrophication, road salt seepage, and introduced piscivores were identified out of 1,469 Adirondack lakes (NY, USA). Paleolimnological techniques revealed that the species assemblages of the reference lakes have undergone a significant change in species composition since before 1900, including increases in warm-water species, large colonial algae, and algal taxa that can cause taste and odour issues in lakes. A subsequent series of case studies which paired reference lakes with acidified lakes revealed that though the acid-impacted lakes were undergoing recovery, they showed similar species shifts to those documented in the reference lakes. These shifting baselines make a return to pre-disturbance state an unreasonable recovery goal for acidified Adirondack lakes. Rather, recovery is likely to be a moving target as novel stressors like climate warming move both reference sites and recovering sites towards novel species assemblages with unknown ecological consequences.

Kristina Arseneau is currently finishing her Ph.D. at Queen’s, where she works in the Paleoecological Environmental Assessment and Research Laboratory with Dr. Brian F. Cumming. Kristina is interested in using paleolimnological techniques to understand biological recovery from acidification and specifically how we can understand and frame biological recovery in multiple stressor environments. Kristina’s fieldwork took place in the Adirondack Park in New York, where she and her field crews hiked in to more than 30 different lakes, dodging moose, overly ambitious beavers, and pathologically curious deer along the way.

Everyone is welcome to attend
Coffee and treats available at the seminar

EEB Seminar: March 27th

Catherine Duguay will talk on

Genetic architecture and sexual conflict in the life-history of Drosophila

at 12:30 in the EEB lounge (BioSciences 4338)

While males and females of a species ‘share’ homologous traits with a common genetic basis, sex-specific selection on these traits can shift the sexes away from their phenotypic optima, inhibiting the evolution of sexual dimorphism. This mode of sexually antagonistic coevolution is known as intralocus sexual conflict (IaSC). As IaSC has been a historically overlooked problem, many outstanding questions remain. For example, what is its contribution in maintaining genetic variation for fitness in populations? What characters underlie this variation in fitness? How does the selection history of the population influence the standing genetic variation? I used the model organism Drosophila melanogaster to attempt to resolve some of these questions. The first part of my Master’s project involved assessing the detectability of sexually antagonistic alleles in populations at different stages of adaptation to the lab. The second part of my Master’s project involved breaking down juvenile fitness into its trait components, such as growth and various morphological metrics, and examining the juvenile stage for antagonism with adult fitness effects. While the first part of my thesis proved inconclusive, the second part revealed a surprising source of sexual conflict in pre-adult stages of D. melanogaster.

Catherine Duguay is a Masters student at Queen’s University working with Adam Chippindale. Catherine is interested in genomic conflict between the sexes. How can males and females of the same species share the majority of their genome, yet have dramatically different strategies for increasing their fitness? Part of her Master’s research involves breeding Drosophilia from different populations to see if divergent sexual selection may function as an isolating mechanism. Catherine did her Bachelors at Western University and a thesis project (with Nusha Keyghobadi) on habitat fragmentation and its consequences to genetic diversity by examining the genetic structure of Wood Frogs in logged and intact forests. Catherine grew up in Quebec City then moved to Fairbanks Alaska, land of the midnight sun, where she lived for four years before returning to Canada.

Everyone is welcome to attend
Coffee and treats available at the seminar