INTERESTING INSECTS

By N A Martin (2019)

Delphacid parasitoid wasp

NeoGonatopus alpinus Gourlay, 1954

This endemic wasp was first found in the 1950’s in the southern alps. It has now been found on the East and West coasts of Auckland. It is a parasitoid of planthoppers in the family Delphacidae (Hemiptera) that live on low growing plants. The wasp adults may be winged or wingless, the latter looking similar to ants.

Conservation status: The wasp parasitoid is probably widespread and is not endangered.

The only known hosts of the wasp are nymphs and brachypterous (short-winged) adults of plant hoppers in the family Delphacidae. The known hosts live on plants close to the ground in coastal and alpine habitats. The adults may be winged or wingless and are probably the overwintering stage. Wasp larvae have been found on hosts in spring and summer.

The head and body of the adult wasp is about 3 mm long and dark brown. The abdomen of the wingless adults has dark hind edges to each abdominal segment. The adults have three pairs of legs and pair of antennae. Winged adults have two pairs of wings. The wingless adult has a narrow thorax, middle section of the body, and legs with swollen segments. Wingless adults may be confused with worker ants.

Eggs are probably laid on large nymphs and short-winged adults. The ectoparasitoid larva pushes its head between body segments, usually between the end of the thorax and the first abdominal segment. The rest of the body extends out between the planthoppers body segments. The larva’s body has two round plates, one above and the other on its underside. As it grows the plates are pushed apart. When the larva is fully grown, it kills the planthopper the then crawls away from its old skin and in a sheltered place it spins a white cocoon in which it pupates. When the adult has developed it 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.

An adult male Delphacid parasitoid wasp, Gonatopus alpinus, (Hymenoptera: Dryinidae) that had been a parasite of a nymph of the Sea celery planthopper, Delphacidae sp. (Apium), (Hemiptera: Delphacidae): note the wasp’s jaws. Creator: Tim Holmes. © Plant & Food Research. [Image: 31GT]

The underside of an adult male Delphacid parasitoid wasp, Gonatopus alpinus, (Hymenoptera: Dryinidae) that had been a parasite of a nymph of the Sea celery planthopper, Delphacidae sp. (Apium), (Hemiptera: Delphacidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 31GV]

Underside side of a winged adult male Delphacid parasitoid wasp, Gonatopus alpinus, (Hymenoptera: Dryinidae) whose larva was a parasite on a nymph of Kiwi spinach planthopper, Delphacidae sp. (Tetragonia), (Hemiptera: Delphacidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 31GB]

Underside side of a winged adult male Delphacid parasitoid wasp, Gonatopus alpinus, (Hymenoptera: Dryinidae) whose larva was a parasite on a nymph of Sea celery planthopper, Delphacidae sp. (Apium), (Hemiptera: Delphacidae). Creator: Tim Holmes. © Underside side of a winged adult male Delphacid parasitoid wasp, Gonatopus alpinus, (Hymenoptera: Dryinidae) whose larva was a parasite on a nymph of Sea celery planthopper, Delphacidae sp. (Apium), (Hemiptera: Delphacidae). [Image: 31GU]

A wingless female Delphacid parasitoid wasp, Gonatopus alpinus, (Hymenoptera: Dryinidae): note the swollen, muscular upper leg segments. The larva had parasitised a nymph of the Sea celery planthopper, Delphacidae sp. (Apium), (Hemiptera: Delphacidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 31GN]

Side view of a wingless adult Delphacid parasitoid wasp, Gonatopus alpinus, (Hymenoptera: Dryinidae): note the swollen, muscular upper leg segments. The larva had parasitised a nymph of the Sea celery planthopper, Delphacidae sp. (Apium), (Hemiptera: Delphacidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 31GP]

Underside of a wingless female Delphacid parasitoid wasp, Gonatopus alpinus, (Hymenoptera: Dryinidae): note the swollen, muscular upper leg segments. The larva had parasitised a nymph of the Sea celery planthopper, Delphacidae sp. (Apium), (Hemiptera: Delphacidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 31GQ]

Nymph of New Zealand spinach planthopper, Delphacidae sp. (Tetragonia), (Hemiptera: Delphacidae) with a larva of the Delphacid parasitoid wasp, Gonatopus alpinus, (Hymenoptera: Dryinidae) attached to its back. Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 31FY]

Side view of a nymph of New Zealand spinach planthopper, Delphacidae sp. (Tetragonia), (Hemiptera: Delphacidae) with a larva of the Delphacid parasitoid wasp, Gonatopus alpinus, (Hymenoptera: Dryinidae) attached to its back. Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 31FZ]

Side view of a nymph of New Zealand spinach planthopper, Delphacidae sp. (Tetragonia), (Hemiptera: Delphacidae) with a larva of the Delphacid parasitoid wasp, Gonatopus alpinus, (Hymenoptera: Dryinidae) attached to its back. Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 31G0]

Side view of an adult Sea celery planthopper, Delphacidae sp. (Apium), (Hemiptera: Delphacidae) with a larva of the Delphacid parasitoid wasp, Gonatopus alpinus, (Hymenoptera: Dryinidae) attached to its back. Creator: Tim Holmes. © Plant & Food Research. [Image: 31GE]

An adult Sea celery planthopper, Delphacidae sp. (Apium), (Hemiptera: Delphacidae) with a larva of the Delphacid parasitoid wasp, Gonatopus alpinus, (Hymenoptera: Dryinidae) attached to its back. Creator: Tim Holmes. © Plant & Food Research. [Image: 31GG]

A dead adult Sea celery planthopper, Delphacidae sp. (Apium), (Hemiptera: Delphacidae) with the larval skin a Delphacid parasitoid wasp, Gonatopus alpinus, (Hymenoptera: Dryinidae) and the white cocoon of the parasitoid on leaves of New Zealand celery, Apium prostratum (Umbelliferae). Creator: Tim Holmes. © Plant & Food Research. [Image: 31GI]

A dead adult Sea celery planthopper, Delphacidae sp. (Apium), (Hemiptera: Delphacidae) with the larva skin a Delphacid parasitoid wasp, Gonatopus alpinus, (Hymenoptera: Dryinidae) on a leaf of New Zealand celery, Apium prostratum (Umbelliferae). Creator: Tim Holmes. © Plant & Food Research. [Image: 31GK]

A white cocoon of a Delphacid parasitoid wasp, Gonatopus alpinus, (Hymenoptera: Dryinidae) on a leaf of New Zealand celery, Apium prostratum (Umbelliferae). Creator: Tim Holmes. © Plant & Food Research. [Image: 31GJ]

Left, the skin of a nymph of New Zealand spinach planthopper, Delphacidae sp. (Tetragonia), (Hemiptera: Delphacidae) and right, a newly spun cocoon of a Delphacid parasitoid wasp, Gonatopus alpinus, (Hymenoptera: Dryinidae) on a stem of New Zealand climbing spinach, Tetragonia implexicoma (Aizoaceae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 31G5]

The skin of a nymph of New Zealand spinach planthopper, Delphacidae sp. (Tetragonia), (Hemiptera: Delphacidae) with the skin of a larva of the Delphacid parasitoid wasp, Gonatopus alpinus, (Hymenoptera: Dryinidae) attached to its back. Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 31G7]

A newly spun cocoon of a Delphacid parasitoid wasp, Gonatopus alpinus, (Hymenoptera: Dryinidae) on a stem of New Zealand climbing spinach, Tetragonia implexicoma (Aizoaceae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 31G6]

A white cocoon of a Delphacid parasitoid wasp, Gonatopus alpinus, (Hymenoptera: Dryinidae) on a leaf of New Zealand celery, Apium prostratum (Umbelliferae). Creator: Tim Holmes. © Plant & Food Research. [Image: 31GR]

An exit hole in cocoon of a Delphacid parasitoid wasp, Gonatopus alpinus, (Hymenoptera: Dryinidae) on a leaf of New Zealand celery, Apium prostratum (Umbelliferae). The hole is made by the adult wasp. Creator: Tim Holmes. © Plant & Food Research. [Image: 31GL]

No pathogens, parasitoids or predators of the Delphacid parasitoid wasp, Gonatopus alpinus, (Hymenoptera: Dryinidae) are known. The adults are probably caught by predatory insects, spiders and birds.

The Delphacid parasitoid wasp has been reared from or associated with four species of plant hoppers in the family Delphacidae (Hemiptera). The female lays an egg on a large nymph or a short-winged, brachypterous, adult. The larva attaches itself between body segments on the upper side. As it grows the body expands and becomes more obvious. Only one larva per plant hopper has been found.

This parasitoid may have more than the four known hosts.

Side view of an adult Sea celery planthopper, Delphacidae sp. (Apium), (Hemiptera: Delphacidae) with a larva of the Delphacid parasitoid wasp, Gonatopus alpinus, (Hymenoptera: Dryinidae) attached to its back. Creator: Tim Holmes. © Plant & Food Research. [Image: 31GF]

An adult Sea celery planthopper, Delphacidae sp. (Apium), (Hemiptera: Delphacidae) with a larva of the Delphacid parasitoid wasp, Gonatopus alpinus, (Hymenoptera: Dryinidae) attached to its back. Creator: Tim Holmes. © Plant & Food Research. [Image: 31GH]

A dead adult Sea celery planthopper, Delphacidae sp. (Apium), (Hemiptera: Delphacidae) with the larval skin a Delphacid parasitoid wasp, Gonatopus alpinus, (Hymenoptera: Dryinidae) and the white cocoon of the parasitoid on leaves of New Zealand celery, Apium prostratum (Umbelliferae). Creator: Tim Holmes. © Plant & Food Research. [Image: 31GI]

A wingless female Delphacid parasitoid wasp, Gonatopus alpinus, (Hymenoptera: Dryinidae): note the swollen, muscular upper leg segments. The larva had parasitised a nymph of the Sea celery planthopper, Delphacidae sp. (Apium), (Hemiptera: Delphacidae) Creator: Tim Holmes. © Plant & Food Research. [Image: 31GM]

A winged male Delphacid parasitoid wasp, Gonatopus alpinus, (Hymenoptera: Dryinidae) whose larva was a parasite on a larval Sea celery planthopper, Delphacidae sp. (Apium), (Hemiptera: Delphacidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 31GS]

Plants of New Zealand celery, Apium prostratum (Umbelliferae) host plant of Sea celery planthopper, Delphacidae sp. (Apium), (Hemiptera: Delphacidae). Creator: Nicholas A. Martin. © Nicholas A. Martin. [Image: 31GX]

Nymph of New Zealand spinach planthopper, Delphacidae sp. (Tetragonia), (Hemiptera: Delphacidae) with a larva of the Delphacid parasitoid wasp, Gonatopus alpinus, (Hymenoptera: Dryinidae) attached to its back. Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 31FY]

Side view of a nymph of New Zealand spinach planthopper, Delphacidae sp. (Tetragonia), (Hemiptera: Delphacidae) with a larva of the Delphacid parasitoid wasp, Gonatopus alpinus, (Hymenoptera: Dryinidae) attached to its back. Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 31G1]

A newly spun cocoon of a Delphacid parasitoid wasp, Gonatopus alpinus, (Hymenoptera: Dryinidae) on a stem of New Zealand climbing spinach, Tetragonia implexicoma (Aizoaceae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 31G6]

The skin of a nymph of New Zealand spinach planthopper, Delphacidae sp. (Tetragonia), (Hemiptera: Delphacidae) with the skin of a larva of the Delphacid parasitoid wasp, Gonatopus alpinus, (Hymenoptera: Dryinidae) attached to its back. Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 31G7]

Winged adult male Delphacid parasitoid wasp, Gonatopus alpinus, (Hymenoptera: Dryinidae) whose larva was a parasite on a nymph of Kiwi spinach planthopper, Delphacidae sp. (Tetragonia), (Hemiptera: Delphacidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 31GA]

A plant of New Zealand climbing spinach, Tetragonia implexicoma, (Aizoaceae), host plant of New Zealand spinach planthopper, Delphacidae sp. (Tetragonia) (Hemiptera: Delphacidae). Creator: Nicholas A. Martin. © Nicholas A. Martin. [Image: 31GC]

Plants of New Zealand climbing spinach, Tetragonia implexicoma, (Aizoaceae), host plant of New Zealand spinach planthopper, Delphacidae sp. (Tetragonia) (Hemiptera: Delphacidae). Creator: Nicholas A. Martin. © Nicholas A. Martin. [Image: 31GD]

Gourlay,E.S. 1954: The Dryinidae, a family of Hymenoptera new to New Zealand. N.Z. ENTOMOL.: 1(4):3-5.

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.