Volf M, Salminen JP, Segar ST. Evolution of defences in large tropical plant genera: perspectives for exploring insect diversity in a tri-trophic context. Current Opinion in Insect Science. 2019. 32:91-97. We review how plant specialized metabolites govern insect-plant reciprocal interactions and diversification of the two groups. We show that escalation and divergence in chemical defences generate different dimensions of plant chemical diversity and how its effects cascade to higher trophic levels. We propose that the effects of chemical α- and β-diversity on herbivores, predators, and parasitoids, depend on the type of metabolite in play and its potency. This review served as a basis for formulating some of the key hypotheses proposed in this project.
Volf M, Segar ST, Miller SE, Isua B, Sisol M, Aubona G, Šimek P, Moos M, Laitila J, Kim J, Zima Jr J, Rota J, Weiblen GD, Wossa S, Salminen JP, Basset Y, Novotny V. Community structure of insect herbivores is driven by conservatism, escalation and divergence of defensive traits in Ficus. Ecology Letters. 2018. 21:83-92. We demonstrate that herbivores with different levels of specialization respond to plant traits with various evolutionary histories. While generalists are affected by escalating defences, specialists are affected by divergent defences of their hosts. This supports differential evolutionary trends among plant defences and their diversity. We propose that the composition of herbivore communities and the nature of biotic selection agents in play can fundamentally affect the trajectories by which plant chemical diversity evolves.
Volf M, Hrcek J, Julkunen-Tiitto R, Novotny V. To each its own: differential response of specialist and generalist herbivores to plant defence in willows. Journal of Animal Ecology. 2015. 84:1123–1132. Plants are involved in diffuse co-evolution with diverse insects. Here we show that it is essential to take this into account when interpreting the evolution of plant defences. It is not the pressure by individual insect species but by their whole assemblages what drives the evolution of plant chemical defences. We show that assemblages of insects with various life-history traits respond to different plant defences. This differential response of herbivore assemblages to plant defences prevents plants from evolving a single, universally efficient defence. Such trends promote the astonishing diversity of plant chemical defences.