If the tape were played again: convergent evolution of clade sizes and taxonomic composition in two tropical assemblages of Coleoptera

Abstract

Communities of insects around the world consist of unique sets of species that have evolved under different historical processes of assembly and lineage diversification. Whole-community phylogenetics can partition the shared and uniquely derived evolutionary history across sites. We used mitochondrial genome sequences of > 1000 species each from two assemblages of Coleoptera (beetles) in distantly situated tropical lowland rainforests of Malaysia and Panama for phylogenetic reconstruction and community ecological analysis. Assemblages were entirely distinct at the species level but were surprisingly similar at the family level in their overall composition and relative species richness. This pattern, coupled with a high degree of phylogenetic clustering, suggests that lineage-specific tendencies have driven evolutionarily independent yet parallel diversification across distinct regions. The inclusion of species-poor lineages reduced the level of community clustering in parallel in both sites, indicating the role of lineage-specific factors in shaping species richness and local community composition. Our findings reveal a strong connection between relative species richness in local communities and global clade sizes, and consistent phylogenetic patterns across assemblages. While biotic exchange in deep time likely played a secondary role, the primary driver appears to be the intrinsic diversification rates unique to each clade (family). Such dynamics make assembly composition more predictable, i.e. replaying the ‘evolutionary tape' would yield similar outcomes wherever a new assemblage of tropical-forest Coleoptera arises.