Intraspecific variation in plant‐associated herbivore communities is phylogenetically structured in Brassicaceae

Abstract

As a result of co‐evolution between plants and herbivores, related plants often interact with similar herbivore communities. Variation in plant–herbivore interactions is determined by variation in underlying functional traits and by ecological and stochastic processes. Hence, typically, only a subset of possible interactions is realised on individual plants. We show that insect herbivore communities assembling on individual plants are structured by plant phylogeny among 12 species in two phylogenetic lineages of Brassicaceae. This community sorting to plant phylogeny was retained when splitting the community according to herbivore feeding guilds. Relative abundance of herbivores as well as the size of the community structured community dissimilarity among plant species. Importantly, the amount of intraspecific variation in realised plant–herbivore interactions is also phylogenetically structured. We argue that variability in realised interactions that are not directly structured by plant traits is ecologically relevant and must be considered in the evolution of plant defences.

Priority effects in herbivore communities vary in effect on plant development and reproduction in four Brassicaceae plant species

“…Finally, the attenuated effect sizes of early-season herbivory in the common garden experiments can be explained by the natural occurrence of the two herbivore species we manipulated. These species are common and readily colonize the plant species used in our experiment under natural conditions (Mertens et al 2021c). Hence, most plants in our experiment interacted with these species at some point in the early-to mid-season stages of their ontogeny.…”

“…These species are annual herbaceous plants native to the Netherlands, have similar ecological niches, are overlapping in their development and phenotype (e.g. S. arvensis is shorter lived than the other plant species and B. nigra typically grows taller than the other plant species), and share a substantial part of the community of herbivore species (Mertens et al . 2021c).…”

“…These species are annual herbaceous plants native to the Netherlands, have similar ecological niches, are overlapping in their development and phenotype (e.g. S. arvensis is shorter lived than the other plant species and B. nigra typically grows taller than the other plant species), and share a substantial part of the community of herbivore species (Mertens et al 2021c). For each plant species, we collected seeds from at least 25 mother plants propagated by open pollination at the experimental fields of Wageningen University, The Netherlands (51°59'26.5"N; 5°39'50.5"E).…”

Plant defense strategies against attack by multiple herbivores

“…Several studies have shown that individual herbivores induce similar suites of defense compounds, where activity of individual compounds may only effectively target a single herbivore species [28,29]. This suggests that either these plant species are not capable of recognizing the specific attacker and thus mount a broad spectrum of defenses or that individual plants are predictably attacked by most of the herbivore species in the pool of potential attackers [20,30]. The costs associated with synthesizing a broad palette of defense compounds may be reduced when compounds are highly multifunctional and are involved in direct and indirect defense as well as other metabolic functions [31,32].…”

Imprints of latitude, host taxon, and decay stage on fungus‐associated arthropod communities

“…In terms of phylogenetic imprints, studies on plantinsect networks have revealed the average herbivore to be fairly specialized in its use of available plant species (Novotny et al, 2002(Novotny et al, , 2006Weiblen et al, 2006). Among plants, closely related taxa tend to share a more similar herbivore fauna (Bernays & Graham, 1988;Forister et al, 2015;Mertens et al, 2021;Volf et al, 2017). These patterns are usually attributed to interspecific differences in plant ecological, morphological, phenological, and chemical properties and phylogenetic conservatism in these traits (Futuyma & Agrawal, 2009;Weiblen et al, 2006).…”