The diversity and evolutionary success of beetles (Coleoptera) are proposed to have arisen from millions of years of specialized trophic interactions with land plants. In particular, ingestion of toxic plant allelochemicals may impose selective pressures that drive genomic diversification and speciation in phytophagous beetles. However, evidence of changes in beetle gene repertoires driven by these interactions remains largely anecdotal and without explicit hypothesis testing. To 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 speciose beetle suborders. By contrasting gene content of species from the phytophagous-rich suborder Polyphaga with those of the mainly predatory Adephaga, we identified families of detoxification enzymes that underwent adaptive expansions in Polyphaga. These genomic signatures that accompany the dietary shift to phytophagy in polyphagous beetles suggest a key role for interactions with plant chemical defenses in driving beetle diversification.

Genomic signatures accompanying the dietary shift to phytophagy in polyphagan beetles