Biology subjects

Wedell, N.

Publications and source records attributed to Wedell, N..

4 recordsLinked to original sources

bioRxiv2026

Dietary landscapes shape genotype- and sex-specific responses to insecticides

Insecticide resistance is typically studied as a response to chemical toxicity, yet in natural and agricultural systems insecticides are embedded within food resources. How resistance alleles interact with nutritional environments to shape fitness remains largely unknown. Here we combine nutritional geometry approaches to test how variation at a major resistance locus, Cyp6g1, modifies sex-specific reproductive performance across dietary landscapes in Drosophila melanogaster. We show that a resistance allele does more than increase survival: it profoundly reshapes reproductive allocation in both sexes. Resistant females exhibited up to a two-fold increase in ovariole number, with benefits amplified in protein-rich, high-calorie diets. In contrast, resistant males displayed increased testis size but reduced seminal vesicle and accessory gland size, revealing sex-specific trade-offs. Critically, contaminating doses of imidacloprid shifted nutritional optima according to genotype, in some cases enhancing reproduction in susceptible flies, consistent with diet-dependent hormesis. Thus, resistance, nutrient availability and toxin exposure jointly determine fitness outcomes. Our findings demonstrate that resistance evolution is embedded within dietary landscapes rather than driven by toxicity alone, highlighting the need to integrate nutritional ecology into predictions of resistance dynamics in human-modified environments.

ecology↗

bioRxiv2020

Identifying genomic markers associated with female re-mating rate in Drosophila pseudoobscura by replicated bulk segregant analysis.

Identifying loci associated with a phenotype is a critical step in many evolutionary studies. Most methods require large sample sizes or breeding designs that can be prohibitively difficult. Here we apply a rarely used approach to identify SNP loci associated with a complex phenotype. We mate siblings from isofemale lines isolate genotypes from three wild populations. After phenotyping we perform whole genome sequencing of isofemale lines from the extremes of the phenotypic distribution of each population and identify SNPs that are consistently fixed for alternative alleles across line pairs. The focal phenotype is female remating rate in the fly Drosophila pseudoobscura, defined as the willingness of a female to mate with a second male after her first mating. This is an integral part of mating system evolution, sexual selection and sexual conflict, and is a quantitative polygenic trait. About 200 SNPs are consistently fixed for alternate alleles in the three pairs of isofemale lines. We use different simulation approaches to explore how many SNPs would be expected to be fixed. We find the surprising result that we uncover fewer observed fixed SNPs than are expected by either simulation approach. We also complete functional analyses of these SNPs. Many lie near genes or regulatory regions known to be involved in Drosophila courtship and mating behaviours, and some have previously been associated with re-mating rates in Genome-Wide Association Studies. Given the small sample size, these results should be treated with caution. Nevertheless, this study suggests that even from a relatively small number of isofemale lines established from wild populations, it is possible to identify candidate loci potentially associated with a complex quantitative trait. However, further work is required to understand modelling the expected distribution of differences.

genomics↗

bioRxiv2019

De novo genome assembly of the meadow brown butterfly, Maniola jurtina

BackgroundMeadow brown butterflies (Maniola jurtina) on the Isles of Scilly represent an ideal model in which to dissect the links between genotype, phenotype and long-term patterns of selection in the wild - a largely unfulfilled but fundamental aim of modern biology. To meet this aim, a clear description of genotype is required.\n\nFindingsHere we present the draft genome sequence of M. jurtina to serve as an initial genetic resource for this species. Seven libraries were constructed using DNA from multiple wild caught females and sequenced using Illumina, PacBio RSII and MinION technology. A novel hybrid assembly approach was employed to generate a final assembly with an N50 of 214 kb (longest scaffold 2.9 Mb). The genome encodes a total of 36,294 genes. 90.3% and 88.7% of core BUSCO (Benchmarking Universal Single-Copy Orthologs) Arthropoda and Insecta gene sets were recovered as complete single-copies from this assembly. Comparisons with 17 other Lepidopteran species placed 86.5% of the assembled genes in orthogroups.\n\nConclusionsOur results provide the first high-quality draft genome and annotation of the butterfly M. jurtina.

genomics↗

bioRxiv2018

Sexual selection drives the evolution of wing interference patterns.

The seemingly transparent wings of many insects have recently been found to display dramatic structural coloration. These structural colours (wing interference patterns: WIPs) may be involved in species recognition and mate choice, yet little is known about the evolutionary processes that shape them. Additionally, existing research has been restricted by analysing WIPs without due consideration of how they are actually perceived by the viewers colour vision. Here, we use multispectral digital imaging and a model of Drosophila vision to compare WIPs of male and female Drosophila simulans from replicate populations forced to evolve with or without sexual selection for 68 generations. We show for the first time that WIPs modelled in Drosophila vision evolve in response to sexual selection, and confirm that WIPs correlate with male sexual attractiveness. These findings add a new element to the otherwise well described Drosophila courtship display and confirm that wing colours evolve through sexual selection.

evolutionary biology↗