Friday Philosophicals

Globally, soils store more carbon than vegetation and the atmosphere, combined, mitigating climate change through carbon sequestration. In addition to climatic variability, human activity through land use has caused a massive quantity of soil carbon to be liberated and released into the atmosphere. There is uncertainty surrounding soil carbon modelling due to the dynamic and complex nature of soil carbon cycling, and recent shifts in theory realize microbial communities as a leading factor in organic carbon stabilization. My research will use field and laboratory methods alongside an existing robust data set to demonstrate the legacy of historical and current land use in soil organic carbon variation and identify how land use influences microbial community structure. My work has important implications for carbon modelling and land management, especially related to long-term effects of land use on soil carbon and the importance of using microbially-explicit carbon models.

Insects rely on external temperatures in order to properly function, however high temperatures combined with extended periods of activity can easily push butterflies into heat stress. The species Parnassius smintheus, or Rocky Mountain Apollo, lives in exposed meadows found along the Rocky Mountains, and are thus subject to direct sunlight and high temperatures for the majority of their flight season. In order to mate, some butterflies will travel between meadows, with distances between meadows ranging between 1 and 10km. Dispersing individuals are relatively rare to find, and so my research seeks to determine whether or not individuals who undergo this short distance migration are better equipped to withstand higher temperatures, due to how intense this flight is. Through use of a flight mill outfitted with a heating element and a thermal camera, performance curves will be assembled to compare individuals who disperse between meadows, and those who do not.

Bluegill sunfish (Lepomis macrochirus) are native to North America and exhibit male parental care and alternative mating strategies, leading to two types of males: parental and cuckolders. Parental males are larger and take care of the young, while cuckolder males are smaller and steal fertilization from parental males using either a sneaking or female mimicry tactic. Previous research has shown that the presence of cuckolder males around nests during spawning reduces the parental male’s perceived paternity, subsequently reducing circulating concentrations of prolactin, an important hormone regulating parental care in many species. These males then provide less care to the offspring in their nest. My research aims to determine if administration of prolactin reverses the cue of reduced paternity (the presence of cuckolder males around the nest) that ultimately leads to less parental care, providing insight into the relationships between all three variables, and the underlying mechanisms for parental care decisions.

Plant litter plays a crucial role in shaping ecosystems by influencing soil nutrients and local species populations. However, despite their distinct plant communities and ecological dynamics, old-field ecosystems remain understudied compared to other environments regarding the effects of plant litter. Human land management practices, such as mowing and leaf litter removal, alter the quality and quantity of plant litter, driving changes in ecosystem structure and function. Plant litter can be broadly categorized into two types: green, non-senesced litter, and brown, senesced litter. Through litter manipulation experiments in an old-field ecosystem, my research will explore how varying amounts of different types of plant litter affect nitrogen cycling and detritivore populations. This work will deepen our understanding of the role of plant litter in nutrient cycling and detritivore communities and offer valuable insights into sustainable land management practices.

Toll-like receptors (TLRs) are proteins that play a critical role in the innate immune response of individuals, acting as a broad initial defence against a wide range of pathogens within a class by targeting highly conserved traits across multiple lineages. Many vertebrate species, including passerine birds, preferentially mate with individuals to maximize the strength of their offspring’s immune system. This can be assortative, with pairs forming between mates that are more similar at specific loci, or disassortative, favouring the pairing of dissimilar alleles. My research will examine the depth of preferential mating occurring between mated pairs of Song Sparrows (Melospiza melodia) within Queen's University Biological Station by evaluating similarity at specific TLR loci, which act against distinct pathogen classes. Additionally, I will examine if the strength of preferential mating at specific TLR types is correlated with the relative threat by evaluating the abundance of pathogenic classes in this community.

Rainbow smelt (Osmerus mordax) are native to eastern North America, in freshwater and oceanic habitats as far west as Ottawa. A large, introduced population was established in the Great Lakes in the 1900s, and smelt have subsequently spread across the Canadian interior. Previous research has shown that rainbow smelt produce thiaminase, an enzyme which induces thiamine deficiency in predators with diets high in smelt. This is one of the factors contributing to the decline of salmon and trout in the Great Lakes. My research aims to determine which Ontario smelt populations are native and establish the timing of postglacial dispersal events. I will then determine whether the thiaminase gene is under selection in different lakes across Ontario and the United States.

Climate change has increased the frequency and intensity of extreme weather events, especially in alpine environments. A species of butterfly native to the Rocky Mountains, Parnassius smintheus, has been the subject of long-term population data collection. This species overwinters as larvae before becoming adult butterflies in the summer. At the long-term study site, three bottlenecks in population size have been observed over the last 30 years, with previous research reporting that unfavorable weather during November is particularly detrimental to summer adult population sizes. Genome-environment association analyses at a broader spatial scale have identified single nucleotide polymorphisms under selection associated with environmental variables relevant to overwinter survival, such as snow cover and minimum/maximum temperatures in early winter. This suggests that extreme weather events might result in changes in adaptive genetic diversity. My research aims to determine whether allelic frequencies of environmentally-associated SNPs are altered following observed population bottlenecks in Parnassius smintheus.

Mycology is an expanding field of study and there is still much about the ecology of fungi that is unknown. Ectomycorrhizal fungi (ECM) live in soil and for symbiotic relationships with vascular plants. Some species produce fruiting bodies which are well recognized but less is known about the below ground community. Carolinian Canada is the most biodiverse region of Canada but lacks documentation of ECM. My research aims to document and understand the community dynamics of ECM in the region. I will collect root samples of known ECM host trees and perform molecular identification to determine what species of fungi are present. Then perform multivariate analysis to explore ECM community composition and factors that influence it. The sequences will be annotated with and added to NCBI GenBank to improve future ECM identification.

Inbreeding (mating between relatives) and inbreeding depression (the phenotypic consequences of inbreeding) are increasing due to habitat fragmentation and population declines. One proposed solution is genetic rescue: introducing genetically distant individuals into a population to promote genetic mixing, reduce deleterious homozygosity, and increase heterozygosity, thereby enhancing fitness and resilience to change. My research focuses on a bighorn sheep population that experienced population decline and subsequent genetic rescue. Using SNP, pedigree, and observational data, I aim to (1) compare theoretical and realized inbreeding coefficients, (2) identify genomic regions associated with inbreeding depression, and (3) evaluate the efficacy of genetic rescue. Ultimately, this work will contribute to the growing body of evidence supporting the use of genomics to study inbreeding and inform conservation strategies for large, long-lived mammals.