INTERESTING INSECTS

By N A Martin (2017)

Planthopper parasitoid

Paradryinus koebelei Perkins, 1905

In New Zealand this adventive wasp is an ectoparasitoid of two species of Australian plant hoppers in the family Flatidae. The wasp larva is usually attached under one of the planthopper nymph’s wing buds. Probably throughout New Zealand where its hosts are present.

Conservation status: An Australian parasitoid of Australian planthoppers.

In New Zealand, the only known hosts of this wasp are nymphs of the two Australian species of plant hoppers in the family Flatidae. Adult wasps have been found from December to May while larvae have been found on plant hopper nymphs from December to April. There are probably several overlapping generations per year.

The adult wasps body is about 5 mm long. The females and males quite different in appearance. Both are dark brown to black, but the female has dark wings with pale bands.

The larva is an ectoparasite on the plant hopper. It is attached under one of the wing buds. The swollen dark brown body protrudes from under the wing bud.

The mature wasp larva moults leaving its old skin attached to the skin of the dead plant hopper nymph. The wasp larva then spins a loose cocoon. Within this it makes a denser cocoon in which it pupates. The adult emerges from the pupa in the cocoon. When its body has hardened and its wings dried it chews a hole in the cocoon through which it emerges.

Dead adult female Planthopper parasitoid, Dryinus koebelei (Dryinidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 2M1Y]

Dead adult female Planthopper parasitoid, Dryinus koebelei (Dryinidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 2M1Z]

Side view of an adult male Planthopper parasitoid, Dryinus koebelei (Dryinidae): note the shape of the abdomen. Creator: Tim Holmes. © Plant & Food Research. [Image: 2M25]

Side view of an adult male Planthopper parasitoid, Dryinus koebelei (Dryinidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 2M26]

Upper side of an adult male Planthopper parasitoid, Dryinus koebelei (Dryinidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 2M28]

Underside of an adult male Planthopper parasitoid, Dryinus koebelei (Dryinidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 2M27]

Nymph of Green planthopper, Siphanta acuta (Flatidae), with a larva of the ectoparasitoid Planthopper parasitoid, Dryinus koebelei (Dryinidae) that has its head inserted under the planthoppers wing bud. Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2M2A]

Underside of a nymph of Green planthopper, Siphanta acuta (Flatidae), with a larva of the ectoparasitoid Planthopper parasitoid, Dryinus koebelei (Dryinidae) that has its head inserted under the planthoppers wing bud. Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2M29]

Nymph of Green planthopper, Siphanta acuta (Flatidae), with a larva of the ectoparasitoid Planthopper parasitoid, Dryinus koebelei (Dryinidae) that has its head inserted under the planthoppers wing bud. Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2M2B]

Nymph of Grey planthopper, Anzora unicolor (Flatidae), with a larva of the ectoparasitoid Planthopper parasitoid, Dryinus koebelei (Dryinidae) that has its head inserted under the planthoppers wing bud. Creator: Tim Holmes. © Plant & Food Research. [Image: 2M1T]

Nymph of Grey planthopper, Anzora unicolor (Flatidae), with a larva of the ectoparasitoid Planthopper parasitoid, Dryinus koebelei (Dryinidae) that has its head inserted under the planthoppers wing bud. Creator: Tim Holmes. © Plant & Food Research. [Image: 2M1U]

Cocoon of Planthopper parasitoid, Dryinus koebelei (Dryinidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 2M1V]

Cocoon of Planthopper parasitoid, Dryinus koebelei (Dryinidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 2M21]

Nymphal of Green planthopper, Siphanta acuta (Flatidae), with skin of a larva of the ectoparasitoid Planthopper parasitoid, Dryinus koebelei (Dryinidae) after the parasitoid larva has left to spin its cocoon. Creator: Tim Holmes. © Plant & Food Research. [Image: 2M22]

Nymphal of Green planthopper, Siphanta acuta (Flatidae), with skin of a larva of the ectoparasitoid Planthopper parasitoid, Dryinus koebelei (Dryinidae) after the parasitoid larva has left to spin its cocoon. Creator: Tim Holmes. © Plant & Food Research. [Image: 2M23]

Skin of a dead nymph of Grey planthopper, Anzora unicolor (Flatidae), after larva of the Planthopper parasitoid, Dryinus koebelei (Dryinidae) has left its host. Creator: Tim Holmes. © Plant & Food Research. [Image: 2M1W]

Cocoon of Planthopper parasitoid, Dryinus koebelei (Dryinidae) with exit hole made by adult wasp Creator: Tim Holmes. © Plant & Food Research. [Image: 2M1X]

Cocoon of Planthopper parasitoid, Dryinus koebelei (Dryinidae) with exit hole made by adult wasp. Creator: Tim Holmes. © Plant & Food Research. [Image: 2M24]

Adults of the Planthopper parasitoid, Dryinus koebelei (Dryinidae) require expert knowledge of Hymenoptera for their identification, but the larvae can be identified on their hosts, nymphs of the Green planthopper, Siphanta acuta and the Grey planthopper, Anzora unicolor (Flatidae).

Dead adult female Planthopper parasitoid, Dryinus koebelei (Dryinidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 2M1Y]

Dead adult female Planthopper parasitoid, Dryinus koebelei (Dryinidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 2M1Z]

Nymph of Green planthopper, Siphanta acuta (Flatidae), with a larva of the ectoparasitoid Planthopper parasitoid, Dryinus koebelei (Dryinidae) that has its head inserted under the planthoppers wing bud. Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2M2B]

Nymph of Grey planthopper, Anzora unicolor (Flatidae), with a larva of the ectoparasitoid Planthopper parasitoid, Dryinus koebelei (Dryinidae) that has its head inserted under the planthoppers wing bud. Creator: Tim Holmes. © Plant & Food Research. [Image: 2M1T]

No pathogens, parasitoids or predators of the Planthopper parasitoid, Dryinus koebelei are known in New Zealand. The adults are probably caught by predatory insects, spiders and birds.

In Australia this parasitoids hosts of Dryinus koebelei are in the family Flatidae. In New Zealand the parasitoid has been found on both Australian species of Flatididae that are present. The parasitoid larva is attached under one of the planthopper’s wing buds. When the wasp larva is fully grown it leaves the planthopper and spins an elongated cocoon.

Nymph of Green planthopper, Siphanta acuta (Flatidae), with a larva of the ectoparasitoid Planthopper parasitoid, Dryinus koebelei (Dryinidae) that has its head inserted under the planthoppers wing bud. Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2M2A]

Nymph of Grey planthopper, Anzora unicolor (Flatidae), with a larva of the ectoparasitoid Planthopper parasitoid, Dryinus koebelei (Dryinidae) that has its head inserted under the planthoppers wing bud. Creator: Tim Holmes. © Plant & Food Research. [Image: 2M1T]

Cocoon of Planthopper parasitoid, Dryinus koebelei (Dryinidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 2M1V]

Olmi M. 2007. New Zealand Dryinidae and Embolemidae (Hymenoptera: Chryidoidea): new records and description of Bocchus thorpei new species. Records of the Auckland Institute and Museum. 44: 5-16.

The New Zealand Institute for Plant & Food Research Limited (Plant & Food Research) for permission to use photographs.