Chemical Camouflage Induced by Diet in a Pest Treehopper on Host Plants

TL;DR

This study shows that a pest treehopper mimics the chemical profile of its host plants to avoid ant predation, using diet to blend in chemically.

Contribution

It demonstrates chemical camouflage in a polyphagous pest insect through diet-induced cuticular hydrocarbon similarity to host plants.

Findings

Treehoppers showed over 80% chemical similarity to two of their host plants.

Chemical similarity depends on the host plant species consumed by the treehoppers.

Chemical camouflage helps treehoppers interact with ants as mutualistic partners.

Abstract

Ants patrol foliage and exert a strong selective pressure on herbivorous insects, being their primary predators. As ants are chemically oriented, some organisms that interact with them (myrmecophiles) use chemical strategies mediated by their cuticular hydrocarbons (CHCs) to deal with ants. Thus, a better understanding of the ecology and evolution of the mutualistic interactions between myrmecophiles and ants depends on the accurate recognition of these chemical strategies. Few studies have examined whether treehoppers may use an additional strategy called chemical camouflage to reduce ant aggression, and none considered highly polyphagous pest insects. We analyzed whether the chemical similarity of the CHC profiles of three host plants from three plant families (Fabaceae, Malvaceae, and Moraceae) and the facultative myrmecophilous honeydew-producing treehopper Aetalion reticulatum (Hemiptera: Aetalionidae), a pest of citrus plants, may play a role as a proximate mechanism serving as a protection against ant attacks on plants. We found a high similarity (>80%) between the CHCs of the treehoppers and two of their host plants. The treehoppers acquire CHCs through their diet, and the chemical similarity varies according to host plant. Chemical camouflage on host plants plays a role in the interaction of treehoppers with their ant mutualistic partners.

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