Life on a deadly trap: Buckleria paludum, a specialist herbivore of carnivorous sundew plants, licks mucilage from glands for defense

Caterpillars of Buckleria spp. (Lepidoptera: Pterophoridae) have a unique feeding habit of eating trap leaves of carnivorous sundew plants (Drosera spp.). We observed the foraging behavior of Buckleria paludum on trap leaves of Drosera spp. and discussed how the moth species avoided being caught by trap leaves. In 81.5% (66/81) of encounters with glandular hairs on adaxial surfaces of Drosera trap leaves, B. paludum larvae licked mucilage and crawled on the processed hairs. The frequency of licking mucilage was significantly higher than the frequency of other behaviors such as eating glandular hairs, chewing bases of them without eating and ignoring when encountering secreted mucilage. Licking mucilage enables the caterpillars to move safely on trap leaves and prevents bending of glandular hairs.