The Evolution of Endophagy in Herbivorous Insects

Abstract

Herbivorous feeding inside plant tissues, or endophagy, is a common lifestyle across Insecta, and occurs in insect taxa that bore, roll, tie, mine, gall, or otherwise modify plant tissues so that the tissues surround the insects while they are feeding. Some researchers have developed hypotheses to explain the adaptive significance of certain endophytic lifestyles (e.g., miners or gallers), but we are unaware of previous efforts to broadly characterize the adaptive significance of endophagy more generally. To fill this knowledge gap, we characterized the limited set of evolutionary selection pressures that could have encouraged phytophagous insects to feed inside plants, and then consider how these factors align with evidence for endophagy in the evolutionary history of orders of herbivorous insects. Reviewing the occurrence of endophytic taxa of various feeding guilds reveals that the pattern of evolution of endophagy varies strongly among insect orders, in some cases being an ancestral trait (e.g., Coleoptera and Lepidoptera) while being more derived in others (e.g., Diptera). Despite the large diversity of endophagous lifestyles and evolutionary trajectories that have led to endophagy in insects, our consideration of selection pressures leads us to hypothesize that nutritionally based factors may have had a stronger influence on evolution of endophagy than other factors, but that competition, water conservation, and natural enemies may have played significant roles in the development of endophagy.

Assessing invertebrate herbivory in human‐modified tropical forest canopies

“…First, different forms of herbivory are weakly correlated either when analyzing the full dataset or when looking within each forest class (Figure S4), so chewing herbivory cannot be used as a reliable proxy of mining or gall-forming herbivores. Second, studies only measuring the leaf area affected may miss key energetic costs for the host plant from gall-forming or mining herbivores (Giron et al, 2016;Tooker & Giron, 2020). Third, overlooking miners and gall formers can limit our understanding of the relative importance of top-down and bottom-up controls (Vidal & Murphy, 2018), as they differ ecologically and are regulated by different top-down processes (Ohgushi et al, 2012;Zvereva et al, 2020).…”

Biotic Threats to Cycas micronesica Continue to Expand to Complicate Conservation Decisions

“…In contrast, a biological control program for the non-native Erechthias leaf miner carries great risk to the native Anatrachyntis pollinator population, as these two genera are closely related. Parasitoids may use cues from leaf-mining activity that are more challenging to find from mining activity [ 73 ], so a particular biological control organism that focuses on the leaf-mining stage may be available. Pursuing this would require the input of an expert in this form of biological control.…”

Plant Allelochemicals as Sources of Insecticides

“…This speciation has driven the evolution of different host plants and food plants [27]. In the course of evolution, plants have developed many resistance mechanisms to reduce the damage caused by insects [28]. Insect adaptations to this defense are mostly related to their biochemical traits [29].…”