The latitudinal diversity gradient in brush-footed butterflies (Nymphalidae): conserved ancestral tropical niche but different continental histories

Abstract

The latitudinal diversity gradient (LDG) is arguably one of the most striking patterns in nature. The global increase in species richness toward the tropics across continents and taxonomic groups stimulated the formulation of many hypotheses to explain the underlying mechanisms of this pattern. We evaluated several of these hypotheses to explain spatial diversity patterns in the butterfly family, Nymphalidae, by assessing the contributions of speciation, extinction, and dispersal to the LDG, and also the extent to which these processes differ among regions at the same latitude. We generated a new, time-calibrated phylogeny of Nymphalidae based on 10 gene fragments and containing ca. 2,800 species (∼45% of extant diversity). Neither speciation nor extinction rate variations consistently explain the LDG among regions because temporal diversification dynamics differ greatly across longitude. For example, we found that Neotropical nymphalid diversity results from low extinction rates, not high speciation rates, and that biotic interchanges with other regions were rare. Southeast Asia was also characterized by a low speciation rate but, unlike the Neotropics, was the main source of dispersal events through time. Our results suggest that global climate change throughout the Cenozoic, particularly during the Eocene-Oligocene transition, combined with the conserved ancestral tropical niches, played a major role in generating the modern LDG of butterflies.

The roles of wing color pattern and geography in the evolution of Neotropical Preponini butterflies

“…The current diversification rate estimated by our likelihood analysis (0.15) is within the range of diversification rates estimated for other butterfly groups (Chazot et al, 2020;Peña & Espeland, 2015). We acknowledge, however, that the models with constant speciation have slightly weaker support than exponentially increasing speciation rate models.…”

“…Fast and erratic flying has been suggested as an antipredator defense mechanism, where predators learn to avoid these species due to the high-cost-low-benefit trade-off (Ruxton et al, 2004;van Someren & Jackson, 1959). rates by influencing speciation and/or diversification (Chazot et al, 2020;De-Silva et al, 2016;Sahoo et al, 2017). This seems to be the case for Preponini as well.…”

“…Similarly, novel habitats and barriers to dispersal created by Neotropical landscape rearrangement have influenced the evolution of a number of butterfly groups (Chazot et al., 2016, 2019; Condamine et al., 2012; De‐Silva et al., 2016, 2017; Toussaint et al., 2019). The increasing availability of comprehensive dated phylogenetic hypotheses for butterflies (Chazot et al, 2020; Espeland et al., 2018) allows a more rigorous study of how different, and potentially conflicting, functions of color have generated trait and species distributions and diversity (Finkbeiner et al., 2014). Phylogenies also enable tests of how shifts in color pattern, in concert with changes in geographic range and habitat, have influenced speciation and diversification (Chazot et al., 2014; Jiggins et al., 2006).…”

“…The Neotropical region contains approximately 45% of species in the family Nymphalidae, the most species-rich family of butterflies (Chazot et al, 2020). The Nymphalidae contains such morphologically diverse groups of species that many currently recognized subfamilies were once treated as families.…”

Bayesian Inference of Ancestral Host–Parasite Interactions under a Phylogenetic Model of Host Repertoire Evolution

“…For both the simulation and empirical studies, we used the phylogenetic relationships between butterfly species in the Nymphalini tribe as proposed by Chazot et al (2020 , Supplementary Fig. S3 available on Dryad) and the phylogenetic relationships between angiosperm families proposed by Magallón et al (2015) .…”