Biology subjects

Bussiere, L. F.

Publications and source records attributed to Bussiere, L. F..

4 recordsLinked to original sources

bioRxiv2024

Exploiting pathogen defence trade-offs to manage risks of crop pests evolving resistance to biocontrol.

Pathogens often exert strong selection, yet host populations maintain considerable genetic variation for resistance, possibly due to environmental heterogeneity causing fitness trade-offs. These trade-offs could help explain genetic variation for pathogen defence, and also constrain resistance evolution to microbial pesticides (an underappreciated risk). However, the presence and strength of such trade-offs remain unclear. We investigate whether pathogen identity or host diet has a stronger effect on the fitness of resistance alleles. We quantify genetic variation and covariation for pathogen resistance in an insect pest across distinct pathogen and plant diet combinations. We demonstrate substantial heritability, indicating considerable risks of biopesticide resistance. Contrary to conventional thinking in host-pathogen biology, we found no strong genetic trade-offs for resisting two fungal pathogen species, but changes in plant diet dramatically altered selection for resistance, revealing diet-mediated genetic trade-offs affecting pest survival. Our data suggest that trade-offs not strictly related to immunocompetence could nevertheless maintain genetic variation for pathogen defence in natural and agricultural landscapes.

evolutionary biology↗

bioRxiv2022

resevol: an R package for spatially explicit models of pesticide resistance given evolving pest genomes

The evolution of pesticide resistance is a widespread problem with potentially severe consequences for global food security. We introduce the resevol R package, which simulates individual-based models of pests with evolving genomes that produce complex, polygenic, and covarying traits affecting pest life history and pesticide resistance. Simulations are modelled on a spatially-explicit and highly customisable landscape in which crop and pesticide application and rotation can vary, making the package a highly flexible tool for both general and tactical models of pest management and resistance evolution. We present the key features of the resevol package and demonstrate its use for a simple example simulating pests with two covarying traits. The resevol R package is open source under GNU Public License. All source code and documentation are available on GitHub.

evolutionary biology↗

bioRxiv2022

What are you lookin' at?: A role for sexual conflict in coevolution of female display signals and male sensory adaptations?

The prevalence and diversity of female ornaments poses a challenge to evolutionary theory because males should prefer mates that spend resources on offspring rather than ornaments. Among dance flies, there is extraordinary variation in sexual dimorphism. Females of many species have conspicuous ornaments (leg scales and inflatable abdominal sacs). Meanwhile males of some species have exaggerated regions of their eyes with larger ommatidial facets that allow for regionally elevated photosensitivity and/or acuity. Here, we conduct a comparative study of these traits using both species descriptions available from the literature, as well as quantitative measures of eyes and ornaments from wild-caught flies. We show a conspicuous covariance across species between exaggerated male dorsal eye regions and the extent of female ornaments: species with highly ornamented females have males with more exaggerated eyes. We discuss this pattern in the context of competing hypotheses for the evolution of these traits and propose a plausible role for sexually antagonistic coevolution.

evolutionary biology↗

bioRxiv2019

Competition for access to mates predicts female-specific ornamentation and polyandry

Sexually selected ornaments are highly variable and the factors that drive variation in ornament expression are not always clear. Rare instances of female-specific ornament evolution (such as in some dance fly species) are particularly puzzling. While some evidence suggests that such rare instances represent straightforward reversals of sexual selection intensity, the distinct nature of trade-offs between ornaments and offspring pose special constraints in females. To examine whether competition for access to mates generally favours heightened ornament expression, we built a phylogeny and conducted a comparative analysis of Empidinae dance fly taxa that display ornate female-specific ornaments. We show that species with more female-biased operational sex ratios in lek-like mating swarms have greater female ornamentation, and in taxa with more ornate females, polyandry is increased. These findings support the hypothesis that ornament diversity in dance flies depends on female receptivity, which is associated with contests for nutritious nuptial gifts provided by males. Moreover, our results suggest that increases in female receptivity lead to higher levels of polyandry and sperm competition among males. The incidence of both heightened pre-mating sexual selection on females and post-mating selection on males contradicts assertions that sex-roles are straightforwardly reversed in dance flies.

evolutionary biology↗