Ejaculate Investment in a Promiscuous Rodent, \u3cem\u3ePeromyscus maniculatus\u3c/em\u3e: Effects of Population Density and Social Role

Questions: How does average male investment in ejaculates vary with changing population density (and thus with the risk of sperm competition) in a promiscuous species? Do individual male investment strategies vary with population density? Data studied: Total testicular mass, somatic mass and annual population density for wild-caught male deer mice, Peromyscus maniculatus, collected by snap-trapping over a 23-year period in Algonquin Provincial Park, Ontario, Canada. Search methods: We analysed the relation between mean testicular mass and mouse population densities across years. To investigate individual investment patterns, we compared the relation between total testicular mass and somatic mass among males for years differing in population density. Conclusions: Average investment in the testes was positively correlated with annual population density. An individual’s investment in testes depended on both the abundance of rival males and on relative body size, a trait associated with social rank

Adventures in Time and Space: What Shapes Behavioural Decisions in Drosophila melanogaster?

Variation in behaviour can be observed both between individuals, based on their condition and experience as well as between populations due to sources of heterogeneity in the environment. These behavioural differences have evolved as a result of natural and sexual selection where different strategies may be favoured depending on the costs and benefits associated with those behaviours. In this thesis I examine two sources of heterogeneity within the environment and their behavioural consequences: how spatial complexity mediates sexual selection over time, and how inter and intraspecific signals and individual condition influence social oviposition behaviour. By increasing spatial complexity, we were able to manipulate male-female interaction rate which in turn influenced courtship behaviour and male-induced harm, the consequence of this was an increase in female fecundity especially in the later days of the assay and no change in offspring fitness. These results supported the idea that spatial complexity is able to mediate sexual selection through decreased harm to females. Oviposition decisions are of high consequence to an individual’s fitness and can be shaped by many environmental conditions. Instead of expending energy to evaluate all their different costs and benefits of the conditions of potential oviposition sites females can chose to rely on the signals left by others, in this case it would be beneficial for females to identify signals most like themselves. While we found females oviposited with individuals of the same species and diet, when given the option they showed more interest in and laid more eggs on media that previously held virgin males, bringing into question many assumptions of copying behaviour. In Drosophila melanogaster the only control females have over their offspring is who they mate with and where they oviposit their eggs, thus, these two factors can have a long-lasting impact on individual fitness for future generations. It is also important to consider how the standard lab environment may be shaping these behaviours, and the consequences this has for the evolutionary trajectory of lab populations

Behavioral Ecology of an Invasive Species: Habitat and Mate Preference(s) in Drosophila Suzukii

The invasive Spotted-Wing fruit fly, Drosophila suzukii, has inflicted substantial economic losses to the soft-fruit agriculture industry worldwide due to the ability of females in this species to use a large, serrated ovipositor to cut the fruit’s skin and lay eggs directly into the mesocarp of ripening fruit. Once the eggs hatch, larvae consume the fruit flesh, ultimately leaving the fruit unmarketable. This species parasitizes numerous commercial fruit types (including blueberries, blackberries, strawberries, raspberries and occasionally grapes) as well as fruits from a variety of wild plant species. Since fruit types vary in their nutritional composition, as well as their spatial and temporal availability, this suggests that D. suzukii experiences considerable environmental heterogeneity. The environment can have a large influence on the development and evolution of morphological, physiological, and behavioural phenotypes and, thus, can have significant implications for individual variation and population growth and change over time. Thus to better understand success if this invasive species we have examined the behavioural and developmental and reproductive performance of D. suzukii as it relates to their local environment. Specifically we focused on the role of the nutritional developmental history (NDH), which can either hinder or support offspring growth and survival, and may be an important factor when selecting habitats. Secondly, as the juvenile NDH has the potential to greatly influence adult phenotypes, and consequently individual reproductive potential, we also examined if NDH influenced the operation of sexual selection. Here we report evidence that NDH is an important factor for D. suzukii females when choosing oviposition sites, and can have dramatic consequences for offspring development, mate-choice, offspring fitness, and ultimately population growth. Information on these two subject areas (habitat and mate choice) is of great potential importance to bettering future management strategies (e.g. by manipulating fly numbers based on host preference and reproductive strategies), which are currently limited by lack of knowledge on the biology of this species

Laurier Biology Departmental Seminars Poster Colouring Book (Vol 1)

Departmental seminar posters are largely utilitarian affairs – who is talking?, when are they speaking?, where is the seminar? (and maybe will there will be refreshments served?). While functional, they often fail to capture the beauty and excitement of their subject matter, and may fail to engage a wider audience. As the organizer of the Wilfrid Laurier University Department of Biology seminar series in 2014, on a lark, I started drawing posters that tried to illustrate our speaker’s research in a non-conventional manner, and hopefully appeal to those that might otherwise find attending a departmental seminar intimidating. Little did I know that 8 years, and \u3e120 posters later, that I would still be at it. Over the years, it has been suggested to me that I assemble these posters into a colouring book, so here you will find some of my all-time favourites

Adventures in Time and Space: What Shapes Behavioural Decisions in Drosophila melanogaster?

Variation in behaviour can be observed both between individuals, based on their condition and experience as well as between populations due to sources of heterogeneity in the environment. These behavioural differences have evolved as a result of natural and sexual selection where different strategies may be favoured depending on the costs and benefits associated with those behaviours. In this thesis I examine two sources of heterogeneity within the environment and their behavioural consequences: how spatial complexity mediates sexual selection over time, and how inter and intraspecific signals and individual condition influence social oviposition behaviour. By increasing spatial complexity, we were able to manipulate male-female interaction rate which in turn influenced courtship behaviour and male-induced harm, the consequence of this was an increase in female fecundity especially in the later days of the assay and no change in offspring fitness. These results supported the idea that spatial complexity is able to mediate sexual selection through decreased harm to females. Oviposition decisions are of high consequence to an individual’s fitness and can be shaped by many environmental conditions. Instead of expending energy to evaluate all their different costs and benefits of the conditions of potential oviposition sites females can chose to rely on the signals left by others, in this case it would be beneficial for females to identify signals most like themselves. While we found females oviposited with individuals of the same species and diet, when given the option they showed more interest in and laid more eggs on media that previously held virgin males, bringing into question many assumptions of copying behaviour. In Drosophila melanogaster the only control females have over their offspring is who they mate with and where they oviposit their eggs, thus, these two factors can have a long-lasting impact on individual fitness for future generations. It is also important to consider how the standard lab environment may be shaping these behaviours, and the consequences this has for the evolutionary trajectory of lab populations

Breaking the Chain – The role of intersexual genetic correlations in sexual dimorphism and the consequences and limits of their evolution

In many sexually reproducing species, males and females often differ in countless ways beyond their primary sexual organs. This phenomenon is known as sexual dimorphism, and it is generally considered to be an adaptive response to differences in the selection pressures experienced by males and females. Despite the advantages associated with sexual dimorphism, it does not evolve completely unhindered – there are plenty of biological effects that can limit the extent and rate of divergence between the sexes. This research project focusses on the potential role of the intersexual genetic correlation (rmf­) – which describes the degree to which brothers and sisters are phenotypically similar to each other – as a limiter on the evolution of sexual dimorphism, a topic of considerable recent debate. We examined the extent to which the intersexual genetic correlation for body size (a sexually dimorphic trait) could be experimentally evolved in replicate populations of fruit flies, Drosophila melanogaster, via selection acting at the family level over the course of five generations. We observed a dramatic (but short-lived) response in rmf­ to selection, which suggests that under the right circumstances that the intersexual genetic correlation is more evolvable than previously thought. A follow-up fitness assay conducted at the end of the experimental evolution period also revealed that some of the intersexual conflict over fitness could be overcome given the right kind of mating patterns. This project provides fresh insight into the relative evolvability of intersexual genetic correlations, as well as empirical evidence on ways in which selection can facilitate the adaptive evolution of sexual dimorphism

The Summer Of The Pivot: Prioritizing Equity In Remote Instruction Through A Multidisciplinary Community Of Practice Initiative At A Canadian University

This article is about the multidisciplinary Community of Practice (CoP) initiative that was implemented in the summer of 2020- summer of the pivot- at a Canadian post-secondary institution to prepare faculty, staff, and students for remote teaching and learning while navigating pandemic conditions created by COVID-19. The CoP as a case study using Critical Theory as a theoretical framework examines the experiences of a collective group of faculty and staff from different disciplines leading a multidisciplinary university-wide initiative and the implications of the approach for promoting effective pedagogies for teaching and learning remotely. Findings based on feedback from workshop attendees, reflections from the CoP facilitators, and comments forwarded to senior administrators about the impact and the effectiveness of the program indicate positive results. It is recommended that although the CoP initiative was originally conceived as a response to the summer of the pivot, it should become an integral approach to promoting dialogue and innovative strategies to advance equitable practices in higher education by cultivating community networks. The findings serve to continue constructive dialogues and discussions about how universities can transition, pivot, and mobilize innovatively and creatively to prioritize equitable teaching and learning conditions that challenge the status quo. This requires a long-term commitment by higher education institutions to break away from historically normalized practices and invest in innovative ways to identify and meet the needs of various stakeholders