Escalona, H. E. | bioRxiv Science

bioRxiv2026

Time-calibrated phylogenomics reveals relationships and parallel evolution of neoteny within Elateriformia (Coleoptera) despite pervasive homoplasy

The controversy over Elateriformia relationships hampers understanding of the evolution of disparate soft-bodied and fully sclerotized phenotypes, bioluminescence, and the ontogenetic reprogramming that leads to larviform females. Elateriformia contains >50,000 species in 34 families, including fireflies, jewel, and click beetles. We sample 31 families and 195 ingroup taxa, each with up to 4,224 orthologs. Through explicit hypothesis testing, coalescent-based approaches, and evaluation of dataset properties, we resolve backbone relationships. We reconfirm the monophyly of Byrrhoidea sensu lato, rejecting the recent resurrection of Dryopoidea, and verify the reciprocally monophyletic lampyroid and elaterid clades. We characterize short internodes and gene-tree discordance, both of which are indicative of ancient rapid radiations. Counterintuitively, signals from moderately variable genes are crucial for resolving certain splits, suggesting that even subtle rate differences distinguish phylogenetically informative loci from overly conserved, less informative markers. Time-calibrated phylogenies indicate the early origin of Elateriformia (281-287 Mya), with superfamilies diverging at the Permian-Triassic boundary and diversifying throughout the Jurassic. We identify 15 independent origins of soft-bodiedness and neotenic modifications spanning the Mid Jurassic to the present. Our hypothesis provides a foundation for investigating the genetic mechanisms underlying ontogenetic reprogramming and bioluminescence.

evolutionary biology↗

bioRxiv2018

Genomic signatures accompanying the dietary shift to phytophagy in polyphagous beetles

BackgroundThe diversity and evolutionary success of beetles (Coleoptera) are proposed to be related to the diversity of plants on which they feed. Indeed the largest beetle suborder, Polyphaga, mostly includes plant-eaters among its ~315,000 species. In particular, plants defend themselves with a diversity of specialized toxic chemicals. These may impose selective pressures that drive genomic diversification and speciation in phytophagous beetles. However, evidence of changes in beetle gene repertoires driven by such interactions remains largely anecdotal and without explicit hypothesis testing.\n\nResultsTo address this, we explored the genomic consequences of beetle-plant trophic interactions by performing comparative gene family analyses across 18 species representing the two most species-rich beetle suborders. We contrasted the gene contents of species from the mostly plant-eating suborder Polyphaga with those of the mainly predatory Adephaga. We found gene repertoire evolution to be more dynamic, with significantly more adaptive lineage-specific expansions, in the more speciose Polyphaga. Testing the specific hypothesis of adaptation to plant-feeding, we identified families of enzymes putatively involved in beetle-plant interactions that underwent adaptive expansions in Polyphaga. There was especially strong support for the selection hypothesis on large gene families for glutathione S-transferase and carboxylesterase detoxification enzymes.\n\nConclusionsOur explicit modeling of the evolution of gene repertoires across 18 species identifies adaptive lineage-specific gene family expansions that accompany the dietary shift towards plants in beetles. These genomic signatures support the popular hypothesis of a key role for interactions with plant chemical defenses, and for plant-feeding in general, in driving beetle diversification.

evolutionary biology↗