When Darwin’s Special Difficulty Promotes Diversification in Insects

Abstract

Eusociality, Darwin's special difficulty, has been widely investigated but remains a topic of great debate in organismal biology. Eusocial species challenge existing theories, and the impact of highly integrated societies on diversification dynamics is controversial with opposing assertions and hypotheses in the literature. Here, using phylogenetic approaches in termites-the first group that has evolved eusociality-we assessed the fundamental prediction that eusocial lineages have higher diversification rates than non-eusocial clades. We found multiple lines of evidence that eusociality provided higher diversification as compared to non-eusociality. This is particularly exacerbated for eusocial species with "true" workers as compared to species with "false" workers. Because most species with "true" workers have an entirely prokaryotic microbiota, the latter feature is also related to higher diversification rates, but it should be investigated further, notably in relation to angiosperm diversification. Overall, this study suggests that societies with "true" workers are not only more successful at ecological timescales but also over millions of years, which further implies that both organism- and species-level traits act on species selection.

Testing multiple hypotheses for the high endemic plant diversity of the Tibetan Plateau

“…Rather they reflect complex interacting historical processes, which is perhaps not surprising given the long-term accumulation of the diversity in the region. This result is also consistent with other studies such as that explaining the biogeography of the amphibians and reptiles in Madagascar as well as those explaining the rapid diversification in Andean bellflowers (Lagomarsino et al, 2016) and insects (Legendre & Condamine, 2018).…”

Gut Bacteria in the Holometabola: A Review of Obligate and Facultative Symbionts

“…The diversity of Holometabola has been explained in the context of adaptive radiation on flowering plants ( Farrell 1998 ), radiation through parasitism ( Forbes et al 2018 ), and eusocial behavior ( Legendre and Condamine 2018 ) as well as the key innovation of the group—complete metamorphosis. Among the holometabolan lineages, it is possible key innovations have driven partnership with gut bacteria ( Moran et al 2019 ).…”

The diversification of termites: inferences from a complete species-level phylogeny

“…They are dominant animals in the soil, comprising up to 40-65% of the total soil macrofaunal biomass (Eggleton et al, 1996;Tuma et al, 2020), and can be responsible for 54-68% of total decomposition in some biotopes (Jouquet et al, 2011;Ashton et al, 2019). Despite the important ecological role of termites on a variety of terrestrial ecosystems, our understanding of the adaptations that led to such high prevalence is still limited (Davis et al, 2009;Legendre and Condamine, 2018).…”

“…More recently, Legendre and Condamine (2018) used parametric methods to explore large-scale diversification patterns in Dictyoptera and found evidence for two main rate shifts: one at the origin of termites (with eusociality) and another at the origin of Termitidae (with the loss of cellulolytic parabasalids symbionts). They also found that lineages with true workers diversified faster than those with pseudergates ("false" workers).…”