POSSIBLE HONOURS THESIS / MENTORSHIP PROJECTS (2021-2022)
Note: this is not a complete list - we will likely have other projects related to urbanization, species interactions, and adaptation, depending on the outcomes of our ongoing research.
(1) How important are closely related species to local diversity? A global test — Closely related species are thought to share many ecological traits and preferences in common, and thus compete for resources within local communities. Despite these costs of competition, recent work suggests that closely related species make up an important component of local diversity, and that their ability to live together may constrain broader patterns of diversification over time. The goal of this project is to document the importance of closely related species to local communities of birds and test the idea that this importance varies with latitude. The work would require compilation of species lists for natural parks and preserves from around the world, beginning with the Americas. Initial tests would involve a taxonomic definition of closely-related species (congeners); additional tests could use a global phylogeny of birds to defines relatedness by the time since they shared a common ancestor.
(2) Reproductive strategies of Nicrophorus pustulatus, an ecologically divergent species of burying beetle — Burying beetles (genus Nicrophorus) are named for their habit of burying small vertebrate carcasses in the ground, and using these carcasses for reproduction. Recent evidence, however, suggests that N. pustulatus might reproduce on carcasses of vertebrates above the ground and even into the forest canopy, where many vertebrates nest. To date, however, N. pustulatus has never been documented successfully breeding in nature on vertebrate carcasses other than snake embryos. This project would identify areas on the Queen's University Biological Station properties where N. pustulatus was especially common in previous above-ground trapping. The work would involve placing 20 bird nesting boxes with mouse carcasses in the canopy at these sites, and revisting these boxes 7-14 days later to test if N. pustulatus successfully breeds in a simulated vertebrate nest, above the ground. The work would also (hopefully!) describe their natural breeding biology.
(3) Behavioural dominance and hybrid pairing in birds — Closely related species sometimes hybridize with each other, but we may expect females of subordinate species to be more likely to mate with males of dominant species, than vice versa, because dominant males should prevail in male-male competition and may be favoured by females because of exaggerated sexually-selected traits (e.g., body size, plumes). A bias in the direction of hybridization matters because it can influence the evolutionary consequences of hybridization for traits that enhance pre-mating isolation (reinforcement). The goal of this project is to use existing data on behavioural dominance of closely related species and patterns of hybrid pairing to test for a bias in patterns of hybridization. Should we find evidence for bias, we will further explore the potential consequences for the evolution of male signals versus female preference. We've compiled data for this project already, but still require searching for additional references on interspecific pairing in the literature (some of this literature is obscure, hard to find, and in languages other than English - it will take some internet detective work).
(4) Do behaviourally subordinate species have greater ecological breadth? — In 1974, Douglas Morse (American Naturalist) described a repeated pattern of socially dominant and subordinate species segregating along environmental gradients. When the dominant species was removed, the subordinate expanded its distribution, suggesting that subordinate species had greater ecological breadth – they were adapted to their own distribution and resources, and to those of the dominant species as well. To date, only one study has independently tested this hypothesis (Freshwater et al. 2014, Ecology) and, surprisingly, found no difference between the ecological breadths of closely-related dominant and subordinate species of birds (examining diet, foraging behaviour, nest sites, and habitat). This test, however, examined ecological breadth in locations where dominant and subordinate species co-occurred, and thus dominant species could have restricted the use of resources and habitats of the subordinate species. This proposed project would extend the work of Freshwater et al. (2014) to examine the ecological breadth of closely-related dominant and subordinate species in areas of sympatry and allopatry, allowing a direct comparison of ecological breadth in areas with and without dominant species. The work would provide one of the few direct tests of Morse's hypothesis, and will further our understanding of how important ecological traits covary with the position of species within a social dominance hierarchy.
(5) What ecological traits covary with behavioural dominance of species? — Previous work in our lab (Freshwater et al. 2014, Ecology) was the first to describe repeated patterns of trait divergence that depended upon the position of a species within a social dominance hierarchy. Specifically, subordinate species of birds arrived earlier on their breeding sites, initiated breeding earlier, had lower annual adult survivorship, laid larger eggs for their weight, and migrated greater distances, than closely-related, dominant species. These patterns were exciting because they suggested that important traits related to phenology, life history, and migration are influenced by where a species sits within a social hierarchy of other species. The work was based on an analysis of 65 closely-related species pairs of North American birds – all of the data on dominance interactions among congeners that was available at the time. Today, we have dominance data for ~200 species pairs of birds from around the world. Are the patterns of trait divergence evident in North American dominance hierarchies representative of birds from around the world? Are other patterns of trait divergence (e.g., geographic range size, distribution) evident among dominant and subordinate species when addressed with a larger sample? This project would revisit some of the questions addressed by Freshwater et al. (2014) using a larger, more powerful, global dataset on dominance relationships among birds.