EEB seminar: March 5th

 

This Thursday, Hayley Roberts will be giving a talk titled:

Understanding Reproductive Phenology in Temperate Frogs

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

The seminar is hosted by the Lougheed Lab

Hayley Roberts and frog

Phenology is an important facet of organismal response to environmental variation, both in terms of seasonality and, over the longer term, climate change. Breeding phenology, the focus of my MSc. thesis, has obvious implications for local adaptation and population persistence. Despite its importance, many aspects of breeding phenology are poorly known in many temperate frogs. My EEB talk focuses on my research into two different aspects of temperate frog phenology at the Queen’s University Biological Station. I first look at differences in within-season temporal trends and abundance between male and female Gray Treefrogs (Hyla versicolor). I predicted asynchronous chorus attendance, with males arriving first and showing peak numbers early but with a sustained chorus, followed by female arrival and quick diminution in numbers after breeding. In contrast to my predictions, I found that the sexes have synchronous peaks and similar patterns of chorus attendance. My second goal is to quantify temporal trends in male size for three temperate frog species, two hylids: Spring Peeper (Pseudacris crucifer), Gray Treefrog (H. versicolor), and one ranid species, the Green Frog (Lithobates clamitans). Green Frogs are primarily territorial while the two hylid species are not reported to be. In addition, production of advertisement calls is thought to be energetically costly for all species, with larger males apparently better able to bear this cost than small ones. These observations have ramifications for expected size distributions of males throughout the breeding season, which I will also explore in my talk. My research highlights the importance of detailed studies of phenology both to increase our understanding of mating systems and how individual populations might vary in response to environmental change.

Hayley is an MSc student in the Lougheed lab.

EEB seminar: February 26th

 

This Thursday, Dr. Jayne Yack will be giving a talk titled:

Caterpillars Scream and Butterflies Listen: Sound Strategies for Avoiding Attack

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

The seminar is hosted by the Martin Lab

yack photo

I am intrigued by the unique sensory systems of animals. In my laboratory we study the acoustic sensory ‘worlds’ of (primarily) insects. Insects have an amazing diversity of sensory organs that detect and process acoustic signals extending far beyond our human sensory capabilities. We employ specialized instruments and methods to tap into these communication channels and identify novel sensory organs.

I will discuss new research on acoustic communication in butterflies and caterpillars- insects whose acoustic sensory capabilities are poorly understood. Although these insects were previously thought to be both deaf and mute, we now have evidence that they rely on a wide range of sounds and vibrations to survive. I will discuss how butterflies use their hearing to eavesdrop on predators, and how some caterpillars whistle, click, scream, and listen to avoid being attacked by predators and parasitoids. I’ll also reflect on how these interesting acoustic communication systems may have evolved.

Dr. Yack is a member of the Biology department at Carleton University. Her lab website can be found here.

EEB seminar: February 12th

 

This Thursday, Nishka Wright will be giving a talk titled:

Is snowmelt the key to understanding plant nutrient availability in the low Arctic?

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

The seminar is hosted by the Grogan Lab

Nishka_Wright_3

Given that soil microbes seem to be superior competitors for nutrients in most terrestrial ecosystems, how plants succeed in acquiring nutrients to support their growth remains a fundamental mystery. I suggest that snowmelt is an event that adversely affects soil microbes providing an opportunity for plants to take up coveted nutrients. As air temperatures warm during the winter-spring transition period, snowmelt water floods the soil. Microbes are distracted as they attempt to acclimatize to new environmental conditions, making them poor competitors for soil nutrients, and resulting in an inadvertent release of their own nutrients to increase soil nutrient pools. Continued snowmelt, however, dilutes soil nutrient pools and masks any increases. In fact, preliminary interpretations of the data suggest that characteristics of the snowpack (i.e. snowpack depth) and the duration of snowmelt, largely determine the magnitude of microbial nutrient release. Diluted nutrients may then flow downslope from the source to accumulate at lower elevations. Altogether, this process may in part explain why plant primary production tends to be greatest in areas of low elevation across the low arctic tundra landscape.

Nishka is an MSc student in the Grogan lab.

EEB seminar: February 5th

 

This Thursday, Dr. Scott A. MacDougall-Shackleton will be giving a talk entitled:

Tell me about your childhood: Stress, developmental phenotypic plasticity, and birdsong

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

The seminar is hosted by the Bonier Lab

MacDougall-Shackleton_1

Sexual selection theory posits that ornaments and displays reflect signaler condition, which in turn is affected by both recent and developmental conditions. Moreover, developmental conditions can induce correlations between sexually selected and other traits if both types of traits are susceptible to developmental stressors. Thus, sexually selected traits may reflect recent and/or developmental characteristics of signalers. I will review data on the relationships between birdsong, a sexually selected trait, and developmental and current condition of songbirds. Field studies of free-living birds indicate that song complexity reflects the size of the song-control brain region HVC, and is correlated with body size and several immune parameters, specifically investment in protective proteins. However, song performance is not correlated to immune investment. Song complexity is correlated with the glucocorticoid stress response, and in some years this stress response predicts overwinter survival. Experimental manipulations have revealed that early life stressors impair development of HVC, but that HVC recovers in size by adulthood. These manipulations result in impaired song complexity and song learning, but not song performance. Experimental developmental stressors also affect growth, endocrine physiology, and metabolism, often in a sex-specific manner. Combined, these studies suggest that song complexity provides reliable information about early developmental experience, and about other traits that have critical developmental periods. Birdsong thus provides a multi-faceted sexually-selected trait that may be an indicator of both developmental and recent conditions.

Dr. MacDougall-Shackleton is visiting us from the University of Western Ontario. His lab website can be found here.

EEB seminar: January 29th

 

This Thursday, Dr. Krista Patriquin will tell us about

Evolution of Sociality in Bats

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

The seminar is hosted by the Ratcliffe Lab

Patriquin_photo_1

Individual costs and benefits of living in groups vary with group size, stability, and composition. Investigations of these features of group living has led to the recognition of a variety of social structures. As part of my PhD work, I examined the causes and consequences of fission-fusion dynamics by exploring the socioecology of female northern long-eared bats, Myotis septentrionalis, which is comparatively less well understood than for those animals with long-term, stable groups.

Like many temperate bats, female northern long-eared bats show natal philopatry to summer areas. During this time, they live in groups with fission-fusion dynamics as individuals move among a network of roosts and roost-groups. I demonstrated that fission-fusion dynamics may be explained, at least in part, by changes in ambient conditions that prompt frequent roost-switching. Yet, despite the highly dynamic nature of these groups, females formed long-term social relationships that were based in part on age and genetic relatedness. These findings have potential consequences for the evolution of social behaviour within groups, such as cooperation and nepotism. These findings also suggest female northern myotis have a similar structure to elephants and whales that live in groups made up of older matriarchs and their descendants.

Recognizing the striking similarities among bats and taxa with culture, including elephants, primates, and cetaceans, I demonstrated through a literature review that bats have group differences in socially-learned foraging behaviour and vocalizations. They also have normative and symbolic behaviour as vocalizations can be used to recognize group members. I therefore concluded there is evidence that bats may have culture, which I will begin to explore as part of my post-doc work.

By answering these questions, I can then look for parallels with other taxa to answer questions about the evolution of different social systems and culture.

Patriquin_photo_2

Dr. Patriquin completed her PhD, focusing on bat social behaviour, at Dalhousie University. She has just migrated to the GTA from Halifax to start an NSERC post-doctoral fellowship at the University of Toronto Mississauga, where she will examine the evolution of social learning in bats.

EEB seminar: January 22nd

 

This Thursday, Dr. Meghan Duffy will talk about

Infectious diseases and food webs: links between Daphnia, parasites, and the larger food web

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

The seminar is hosted by the Nelson Lab

Meghan_Duffy_1

There is general interest in understanding the effects of parasites on host populations, communities, and ecosystems. My talk will be in two parts, both of which will feature the Daphnia-fungal parasite system that has been the focus of much of my research. In the first part of the talk, I will present evidence that parasite epidemics can increase host density via a hydra effect. We have found that infected Daphnia have greatly reduced feeding rates, and that, in certain environments, this can lead to higher host density during epidemics. In the second part of the talk, I will focus on how adding an invasive host species can alter host-parasite interactions. We found that the invasive host was more competent than the native host, which suggested that it should amplify disease in the native host. However, in community-scale experiments, we found that the native (lower competence) host increased disease in the invasive host. Our empirical and theoretical results suggest that these counterintuitive patterns were driven by host density, parasite degradation rates, and asymmetry in intra- and interspecific competition. Thus, host competence is not sufficient for predicting how invasive hosts will alter disease.

Dr. Duffy is a member of the EEB Department at the University of Michigan. Her lab’s research examines the causes and consequences of parasitism in natural populations, focusing on lake populations of Daphnia. The Duffy lab website can be found here.