Female treehoppers camouflage behaviour is evidenced during oviposition on wild shrubs

Various species of treehoppers possess a structure known as ‘helmet’ that may work as a camouflage feature (i.e. masquerade) by mimicking plant thorns. The helmet is expected to provide an adaptive advantage against predators if treehoppers choose to stay closer to thorns during times of vulnerability. The treehopper Enchenopa brasiliensis Strümpel possess a helmet that visually resembles the leaf thorns of its host plant, the wolf apple shrub Solanum lycocarpum St. Hill. In a field study, I examined the hypothesis that females of E. brasiliensis exhibit a potential camouflage behaviour by choosing to oviposit next to leaf thorns of S. lycocarpum. In fact, the results reveal that females of E. brasiliensis preferred to oviposit mostly on leaf midribs of S. lycocarpum possessing thorns as opposed to those without thorns. Additionally, females preferred to lay eggs closer to larger clusters of midrib thorns. This finding suggests that this oviposition/camouflage behaviour will likely increase the chances of female treehoppers being misidentified by predators; therefore, characterizing the mechanism of masquerade/deceptive resemblance. In a broader sense, this study also provides further evidence on how the narrow ecological relationships between plants and specialist herbivores can fuel the evolution of specific behavioural adaptations.