Revisiting the evolution of ecological specialization, with emphasis on insect–plant interactions

Abstract

Abstract. Ecological specialization is a fundamental and well-studied concept, yet its great reach and complexity limit current understanding in important ways. More than 20 years after the publication of D. J. Futuyma and G. Moreno's oft-cited, major review of the topic, we synthesize new developments in the evolution of ecological specialization. Using insectplant interactions as a model, we focus on important developments in four critical areas: genetic architecture, behavior, interaction complexity, and macroevolution. We find that theory based on simple genetic trade-offs in host use is being replaced by more subtle and complex pictures of genetic architecture, and multitrophic interactions have risen as a necessary framework for understanding specialization. A wealth of phylogenetic data has made possible a more detailed consideration of the macroevolutionary dimension of specialization, revealing (among other things) bidirectionality in transitions between generalist and specialist lineages. Technological advances, including genomic sequencing and analytical techniques at the community level, raise the possibility that the next decade will see research on specialization spanning multiple levels of biological organization in non-model organisms, from genes to populations to networks of interactions in natural communities. Finally, we offer a set of research questions that we find to be particularly pressing and fruitful for future research on ecological specialization.

Extinction cascades partially estimate herbivore losses in a complete Lepidoptera–plant food web

“…4, Appendix B: Fig. B3), which mirrors a global pattern of specialists being more susceptible to extinction (Forister et al 2012). Overall, however, most monophagous Lepidoptera species feed on plants that are both geographically widespread, and also host to many other herbivore species (Fig.…”

Influence of plant resistance traits in selectiveness and species strength in a tropical plant‐herbivore network

“…Because species strength of plants increased as a function of selectiveness (specialization) of their herbivores and was unrelated to plant cover, plant-herbivore interactions do not seem to be determined by neutral factors related to plant abundance, but rather by other factors aff ecting diet breadth and host choice, such as plant defense ( Coley and Barone, 1996 ;Agrawal, 2005 ;Poelman et al, 2008 ;Forister et al, 2012Forister et al, , 2015Richards, et al, 2015 ).…”

“…Th e most abundant plant species (i.e., those with most biomass or cover) tend to be related to a greater number of herbivore species ( Basset, 1991 ;Marques et al, 2000 ;Whitfeld et al, 2012 ) simply by having a greater probability of being found, that is, a greater apparency ( Feeny, 1976 ). However, in the particular case of tropical systems, where herbivorous insects are highly specialized to their host plants ( Novotny et al, 2002 ;Novotny and Basset, 2005 ;Ødegaard et al, 2005 ;Weiblen et al, 2006 ;Forister et al, 2012Forister et al, , 2015, it is likely that species strength is independent from the host plants biomass or abundance. In this case, plant resistance traits play an important role infl uencing herbivore preferences ( Coley and Barone, 1996 ;Stamp, 2003 ;Agrawal, 2005 ;Poelman et al, 2008 ) and thus their species strength, or their relative importance as food for herbivores.…”

Patterns of gall infestation in Heteropterys byrsonimifolia A. Juss. in a forest-savannah ecotone

“…Ecological interactions elucidate evolutionary and co-evolutionary paths (Jordano et al, 2003;Agrawal et al, 2012;Forister et al, 2012) and provide numerous ecosystem services, such as pollination (Kaiser-Bunbury et al, 2010) and dispersion (Jordano et al, 2003). Interactions considered "disharmonic", such as herbivory, predation, competition and parasitism, also play important roles, especially in controlling antagonistic populations (Van der Putten et al, 2001) and deserve to be investigated to elucidate the determinant parameters in these processes.…”