Biology subjects

Boggs, C. L.

Publications and source records attributed to Boggs, C. L..

3 recordsLinked to original sources

bioRxiv2024

Genetic basis of an adaptive polymorphism controlling butterfly silver iridescence

Identifying the genes and mutations that drive phenotypic variation and which are subject to selection is crucial for understanding evolutionary processes. Mormon Fritillary butterflies (Speyeria mormonia) exhibit a striking wing color polymorphism throughout their range: typical morphs bear silver spots on their ventral surfaces, and can co-occur with unsilvered morphs displaying a dull coloration1. Through genome-wide association studies in two polymorphic populations, we fine-map this difference in silvering to the 3 region of the transcription factor gene optix. The expression of optix is confined to the unsilvered regions that surround the spots, and these patterns are transformed to a silver identity upon optix RNAi knockdown, implicating optix as a repressor of silver scales in this butterfly. We show that the unsilvered optix haplotype shows signatures of recent selective sweeps, and that this allele is shared with the monomorphic, unsilvered species Speyeria hydaspe, suggesting that introgressions facilitate the exchange of variants of adaptive potential across species. Remarkably, these findings parallel the role of introgressions and cis-regulatory modulation of optix in shaping the aposematic red patterns of Heliconius butterflies2-7, a lineage that separated from Speyeria 45 million years ago8. The genetic basis of adaptive variation can thus be more predictable than often presumed, even for traits that appear divergent across large evolutionary distances. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=199 SRC="FIGDIR/small/628425v1_ufig1.gif" ALT="Figure 1"> View larger version (112K): org.highwire.dtl.DTLVardef@5d2a9borg.highwire.dtl.DTLVardef@982c74org.highwire.dtl.DTLVardef@8e90b3org.highwire.dtl.DTLVardef@1bddf3c_HPS_FORMAT_FIGEXP M_FIG Graphical Abstract C_FIG

evolutionary biology↗

bioRxiv2024

Genetic Mechanisms underlying Preference-Performance Mismatches: Insights from a Specialized Native Herbivore on an Invasive Toxic Plant

Specialist phytophagous insects have a narrow hostplant range for optimal development and survival. Mismatches between female oviposition preference and larval performance can lead to high fitness costs. Understanding the mechanistic basis of this decoupling can help us understand evolutionary constraints and aid in predicting outcomes of error-prone oviposition. We investigated the causes for preference-performance mismatches in a specialist native herbivore laying eggs on an invasive toxic plant. Transcriptomic analyses revealed no differential gene expression in gustatory/olfactory organs of adult females with different oviposition preference, but larvae exhibit host-plant-specific gene expression signatures. The larvae feeding on toxic plants showed lower expression of specialized detoxification enzymes and higher expression of general digestive enzymes, indicating the inability of larvae to detoxify toxic compounds present in the toxic plants. We additionally found that genes related to successful detoxification and adaptive feeding were enriched in larvae feeding on native plants, while genes related to toxic responses, apoptosis and accelerated development were enriched in larvae feeding on toxic plants. Our findings dissect genetic mechanisms behind preference-performance mismatches, quantifying the impact of error-prone oviposition on larval performance in specialized species interaction.

evolutionary biology↗

bioRxiv2023

Gene family evolution in brassicaceous-feeding insects: Implications for adaptation and host plant range.

Herbivores have a defined range of hostplants that they can feed on, which is mediated by underlying detoxification and sensory repertoires. Insects that feed on Brassicaceae represent one of the striking examples of co-evolutionary arms race. Insects specialized on Brassicaceae have evolved specific mechanisms to detoxify mustard oils (glucosinolates), while generalist species use detoxification enzymes that act on a variety of substrates. Understanding the gene evolution of detoxification and sensory repertoire in specialist and generalist Brassicaceae feeders will shed light on the processes involved in mediating hostplant ranges in herbivores. We use a comparative phylogenomic approach in 12 lepidopterans that feed on Brassicaceae, ranging from specialist to pests in their host range to examine the gene family expansion of detoxification and sensory gene families. We found that gene family expansions and contractions were larger in generalist herbivores compared to specialist herbivores. Gene evolutionary rate of detoxification genes reflected hostplant range where generalists had a higher evolutionary rate of detoxification genes that act on wide substrates while specialists had a higher evolutionary rate in genes that conjugate toxic compounds to hydrophilic byproducts. Our analysis on the nitrile specifier gene, a key innovation for feeding on Brassicaceae, indicated pervasive purifying selection with lineage specific differences in selection. Our results add to the growing body of work addressing gene family evolution and its role in hostplant range and specialization in insects.

evolutionary biology↗