Predatory insects and spiders
Leafhoppers appear to have few natural enemies. They are preyed on by nabid bugs and spiders.
Parasitic flies and wasps
Parasitic flies and wasps are the most important natural enemies of leafhoppers.
- Pipunculid parasitic flies in the genus Chalarus lay their eggs singly into the abdomen of third to fifth instar leafhopper nymphs.
- The larva of the parasites have two instar stages, the second only occurring in the adult host.
- The parasite larva consumes most of the host’s tissues and emerges through its skeleton. Up to 20% parasitism has been recorded.
Dryinid parasitic wasps in the genus Aphelopus also inject their eggs singly into the abdomen of leafhopper nymphs.
- The egg hatches when the nymphs are mature or when they reach adulthood.
- Dryinid parasitic wasps have five larval instars but only for the first two instars is the body of the parasite entirely within the host’s body.
- The late second and subsequent instars are semi-external.
- The parasites head and part of its tail remain inside the host but the remainder is external and curves between the attachment points in an arc.
- The external parts contain a brown/black sack, which contains moulted skins.
- Development takes about six weeks.
- The larvae then splits the sack with the head remaining attached to the host while the parasite consumes it.
- The larva then moves away and spins a cocoon in which it pupates. Aphelopus species can cause up to 20% parasitism.
Another group of parasitic wasps, the mymarids known as fairy flies (Anagrus, Anaphes, Gonatocerus and Polynema species), are egg parasite and can sometimes cause high levels of parasitism.