Planthopper Parasite Moths: the caterpillars of this family are parasites that attach themselves to the bodies of other insects and then gradually feed on the fluids within the host's abdomen
Above: the larval form of Fulgoraecia exigua
Caterpillars of the family Epipyropidae, commonly known as planthopper parasite moths, are ectoparasites that feed on the haemolymph (i.e. "blood") of planthoppers and cicadas. This family contains at least 40 described species, all of which are parasites or parasitoids.
Above: planthopper parasite caterpillars tucked beneath the wings of their hosts
This is one of the few known examples of a caterpillar that actually engages in parasitic, carnivorous and/or predatory behavior.
Above: Fulgoraecia exigua
The caterpillar has hooked claws that allow it to cling to the host's body; it uses its mandibles to penetrate the cuticle around the abdomen, then inserts a proboscis-like structure into the planthopper's body and begins to feed on the fluids within.
Each caterpillar spends about 4-6 weeks feeding on its host, with its body often tucked beneath the larger insect's wings.
Above: a Fulgoraecia exigua caterpillar can be seen feeding beneath the wings of this planthopper
Young planthopper nymphs that are parasitized by these caterpillars rarely survive the process. The survival rate for older nymphs and adult hemipterans is also quite low.
Above: the photo at the top shows an Epipomponia nawai caterpillar feeding on a cicada, while the photo on the bottom shows Fulgoraecia exigua feeding on a leafhopper
Planthopper parasite caterpillars are often tiny, with their bodies measuring just 3-7mm long, and they're covered in waxy white filaments that make them look like little cottonballs. These features seem to mimic the "fluffy" appearance of many fulgoroid planthopper nymphs, which may enable the caterpillar to sneak up on its host.
Above: planthopper parasite caterpillars
When the caterpillar reaches maturity, it finally detaches from its host and then uses a thin strand of silk to abseil down to a leaf or a branch, where it can spin a cocoon around its body and enter pupation.
Above: the cocoons of Fulgoraecia exigua
The caterpillars of this family create very distinctive cocoons. As delicate layers of silk are folded together around the pupal case, they often form ridges, cone-like structures, or wider, flatter folds that look almost like rose petals.
Above: a cocoon made by an unidentified moth from family Epipyropidae
The fully-developed moth may emerge weeks or even months later, depending on the species. The adults of this family typically have a blackish-gray appearance.
Above: the adult form of Epipomponia nawai
Other examples of predatory, carnivorous and/or parasitic moths can be found in my earlier post about meat-eating caterpillars.
Sources & More Info:
Journal of the Lepidopterist's Society: Predatory and Parasitic Lepidoptera
The Lepidoptera: Form, Function, and Diversity: Epipyropidae
Moths of North Carolina: Fulgoraecia exigua
Bug Guide: Family Epipyropidae
Bombay Natural History Society: The Biology and Morphology of Epipyrops eurybrachydis
Egyptian Journal of Biological Pest Control: Parasitism by Fulgoraecia melanoleuca
Journal of Asia-Pacific Entomology: Behavioural and Phylogeographic Observations on Epipomponia nawai
Species Connect: Carnivorous Butterflies and Moths
