Project description:Developmental mechanisms play an important role in determining the costs, limits, and evolutionary consequences of phenotypic plasticity. One issue central to these claims is the metaphor of developmental “decoupling,” where alternate morphs result from evolutionarily independent developmental pathways. We test this assumption through a microarray study that explores differences in gene expression between alternate morphs relative to differences between sexes, a classic example of developmental decoupling. We then examine whether morph-biased genes are less conserved, relative to morph-shared genes, as predicted if developmental decoupling relaxes pleiotropic constraints on divergence. We focus on the developing horns and brains of two species of horned beetles with spectacular sexual- and morph-dimorphism in the expression of horns and fighting behavior. We find that patterns of gene expression were as divergent between morphs as they were between sexes. However, overall patterns of gene expression were also highly correlated across morphs and sexes. Morph-biased genes were more evolutionarily divergent, suggesting a role of relaxed pleiotropic constraints or relaxed selection. Together these results suggest that alternate morphs are somewhat developmentally decoupled, and that this decoupling has significant evolutionary consequences. However, alternative morphs may not be as developmentally decoupled as sometimes assumed and such hypotheses of development should be revisited and refined. We compared gene expression in three focal epidermal tissues (head, prothorax, legs) relative to a "control" tissue (dorsal abdominal epidermis) without any outgrowths. We also surveyed gene expression in the brain, relative to ganglionic neural tissue. We compared such patterns of gene expression between two male morphs (horned, fighter and hornless, sneaker males) and between males and females. We focused our array analyses (N = 48 arrays) on Onthophagus taurus (the species for which the array was designed), but also ran 19 arrays on thoracic tissue of Onthophagus nigriventris, a species which expresses thoracic horns as adults (O. taurus expresses head horns). Finally, we included a small subset of arrays (N = 4) directly hybridizing head epidermis tissue of O. taurus male morphs to validate our overall estimates of morph-biased expression. For more detail, refer to Snell-Rood et al. 2010, Evolution.
Project description:Seminal fluid protein (SFP) composition is complex and commonly assumed to be rapidly divergent due to functional interactions with both sperm and the female reproductive tract (FRT), both of which evolve rapidly. In addition to sperm, seminal fluid may contain structures, such as mating plugs and spermatophores. Here, we investigate the evolutionary diversification of a lesser-known ejaculate structure: the spermatostyle, which has independently arisen in several families of beetles and true bugs. We characterized the spermatostyle proteome, in addition to spermatostyle and FRT morphology, in six species of whirligig beetles (family Gyrinidae). Spermatostyles were enriched for proteolytic enzymes, and assays confirmed they possess proteolytic activity. Sperm leucyl aminopeptidases (S-LAPs) were particularly abundant, and their localization to spermatostyles was confirmed by immunohistochemistry. Although there was evidence for functional conservation of spermatostyle proteomes across species, phylogenetic regressions suggest evolutionary covariation between protein composition and the morphology of both spermatostyles and FRTs. We postulate that S-LAPs (and other proteases) have evolved a novel structural role in spermatostyles and discuss spermatostyles as adaptations for delivering male-derived materials to females.
Project description:Developmental mechanisms play an important role in determining the costs, limits, and evolutionary consequences of phenotypic plasticity. One issue central to these claims is the metaphor of developmental “decoupling,” where alternate morphs result from evolutionarily independent developmental pathways. We test this assumption through a microarray study that explores differences in gene expression between alternate morphs relative to differences between sexes, a classic example of developmental decoupling. We then examine whether morph-biased genes are less conserved, relative to morph-shared genes, as predicted if developmental decoupling relaxes pleiotropic constraints on divergence. We focus on the developing horns and brains of two species of horned beetles with spectacular sexual- and morph-dimorphism in the expression of horns and fighting behavior. We find that patterns of gene expression were as divergent between morphs as they were between sexes. However, overall patterns of gene expression were also highly correlated across morphs and sexes. Morph-biased genes were more evolutionarily divergent, suggesting a role of relaxed pleiotropic constraints or relaxed selection. Together these results suggest that alternate morphs are somewhat developmentally decoupled, and that this decoupling has significant evolutionary consequences. However, alternative morphs may not be as developmentally decoupled as sometimes assumed and such hypotheses of development should be revisited and refined.
Project description:This series examines gene expression patterns in the head horns, thoracic horns, and legs of the horned beetles Onthophagus taurus. Expression in each of these tissues was compared to that in common non-appendage reference - abdominal epithelium.
Project description:We characterized sperm from the seminal vesicles of male monarch butterflies (Danaus plexippus), in triplicate, identifying 548 high confidence proteins. As with all but the most basal lepidopteran species male monarch butterflies are sperm heteromorphic, producing fertilization competent and anucleate fertilization incompetent sperm morphs. Comparing this data to the sperm proteomes of the Carolina sphinx moth (Manduca sexta) and the fruit fly (Drosophila melanogaster) demonstrated high levels of functional coherence across proteomes, and conservation at the level of protein abundance and post-translational modification within Lepidoptera. Comparative genomic analyses revealed a significant reduction in orthology among Monarch sperm genes relative to the remainder of the genome in non-Lepidopteran insects. A substantial number of sperm proteins were found to be specific to Lepidoptera, lacking detectable homology outside this taxa. These findings are consistent with a burst of genetic novelty in the sperm proteome concurrent with the origin of heteromorphic spermatogenesis early in Lepidoptera evolution.
Project description:We report the temporal dynamics of differential gene expression between primed and unprimed beetles infected with the entomopathogen Bt
Project description:Queens of social insects have the remarkable ability to keep sperm alive for years within their specialized storage organ, the spermatheca. Despite being one of the most critical determinants of colony health, precisely what biochemical processes enable this sustained sperm viability are largely unknown. Here, we survey quality metrics (sperm count, sperm viability, and ovary size) of honey bee queens from nine genetic sources. We then performed quantitative proteomics on spermathecal fluid from N = 123 individual queens in order to investigate the biochemical processes underlying natural variation in sperm viability.
Project description:Proteomic analysis of the microbiome of beetle intestinal content from wood eating beetles as related to lignocellulose deconstruction and colony subsistence
Project description:This series examines gene expression patterns in the head horns, thoracic horns, and legs of the horned beetles Onthophagus taurus. Expression in each of these tissues was compared to that in common non-appendage reference - abdominal epithelium. The series consists of three pair-wise comparisons: head horn versus abdominal epithelium, thoracic horn versus abdominal epithelium and legs versus abdominal epithelium. Each tissue sample was obtained by pooling tissue dissected from four pupae. Samples compared on the same array were derived from tissues dissected from the same four animals. Five independent biological replicates were performed for each comparison with dye flips (three in one direction and two in the opposite direction).