Divergent evolution in antiherbivore defences within species complexes at a single Amazonian site

Abstract

Summary1. Classic theory in plant-insect interactions has linked herbivore pressure with diversification in plant species. We hypothesize that herbivores may exert divergent selection on defences, such that closely related plant species will be more different in defensive than in non-defensive traits. 2. We evaluated this hypothesis by investigating two clades of closely related plant species coexisting at a single site in the Peruvian Amazon: Inga capitata Desv. and Inga heterophylla Willd. species complexes. We compared how these lineages differ in the suite of chemical, biotic, phenological and developmental defences as compared to non-defensive traits that are related to habitat use and resource acquisition. We also collected insect herbivores feeding on the plants. 3. Our data show that sister lineages within both species complexes are more divergent in antiherbivore defences than in other non-defensive, functional traits. Moreover, the assemblages of herbivore communities are dissimilar between the populations of coexisting I. capitata lineages. 4. Synthesis. Our results are consistent with the idea that for the I. capitata and I. heterophylla species complexes, interactions with their natural enemies may have played a significant role in their phenotypic divergence and potentially in their diversification and coexistence. It also suggests that defensive traits are evolutionary labile.

Are the metabolomic responses to folivory of closely related plant species linked to macroevolutionary and plant–folivore coevolutionary processes?

“…; Endara et al. ) is thus not trivial, because both hypotheses may play important roles, as supported by our results (Figs. A, ).…”

“…; Endara et al. ). The species of insects and the evolutionary histories of plant–insect interactions would be thus two crucial factors determining the chemical defensive composition of plants.…”

A thorny issue: Woody plant defence and growth in an East African savanna

“…This work has shown that within one overarching defence syndrome (nutrition and defence), species within a community can widely diverge in their adopted defence strategies. Endara et al () reported high levels of dissimilarity in the defences of closely related co‐occurring forest species and suggest that this would be necessary for the coexistence of closely related neighbours and could account for the high local diversity of tropical forests. Similarly, we suggest that diverse defence strategies enable savanna species (which are often closely related) to occupy different niches and defend against different types of herbivores resulting in more resilient and species rich woody communities.…”

Defensive traits exhibit an evolutionary trade‐off and drive diversification in ants

“…Predation has been invoked as an important selective force influencing clade diversification and morphological divergence across many taxa, including plants (Agrawal ; Weber and Agrawal ; Endara et al. ), amphibians (Arbuckle and Speed ), dragonflies (Mikolajewski et al. ), and beetles (Ge et al.…”