''Trissolcus basalis'', or the green vegetable bug egg parasitoid, is a parasitoid wasp in the family

Platygastridae The hymenopteran family Platygastridae (sometimes incorrectly spelled Platygasteridae) is a moderate-sized group (about 2000 described species) of exclusively parasitoid wasps, mostly very small (1–2 mm), black, and shining, with genicul ...

known primarily for parasitising the horticultural pest ''

Nezara viridula ''Nezara viridula'', commonly known as the southern green stink bug (USA), southern green shield bug (UK) or green vegetable bug (Australia and New Zealand), is a plant-feeding stink bug. Believed to have originated in Ethiopia, it can now be f ...

'', the green vegetable bug.

Description

Like other species of '' Trissolcus'', ''T. basalis'' is small (around 2mm long), mostly black in colour, and females have clubbed antennae. ''Trissolcus basalis'' can be separated from other

nearctic The Nearctic realm is one of the eight biogeographic realms constituting the Earth's land surface. The Nearctic realm covers most of North America, including Greenland, Central Florida, and the highlands of Mexico. The parts of North America ...

'' Trissolcus'' species by the presence of coriaceous microsculpture on the mesoscutellum, pustulate setal bases, shallowly impressed episternal foveae on the mesopleuron, and an incomplete netrion sulcus.

Life cycle

''Trissolcus basalis'' is a solitary

endoparasitoid In evolutionary ecology, a parasitoid is an organism that lives in close association with its host (biology), host at the host's expense, eventually resulting in the death of the host. Parasitoidism is one of six major evolutionarily stable str ...

, completing development within the eggs of pentatomid bugs. Females use their clubbed-shape antennae to palpate eggs laid by their primary host, ''

''. When ready to oviposit, the female faces away from the egg and backs into it, inserting her

ovipositor The ovipositor is a tube-like organ used by some animals, especially insects, for the laying of eggs. In insects, an ovipositor consists of a maximum of three pairs of appendages. The details and morphology of the ovipositor vary, but typica ...

through the wall of the egg. Once finished ovipositing, the female withdraws her ovipositor and wipes the tip across the egg surface to mark the egg. After adults have completed development, males emerge first followed by females a couple of days later. Males mate with females as they emerge from the egg.

Ecology

New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...

, ''T. basalis'' has been recorded from non-target hosts including ''Cermatulus nasalis'' (Woodward, 1837), ''Cuspicona simplex'' Walker, 1867, Green potato bug, ''Dictyotus caenosus'' (Westwood, 1837), '' Glaucias amyoti'' (Dallas, 1851), '' Monteithiella humeralis'' (Walker, 1868), and ''Oechalia schellenbergii'' (Guerin, 1831). It has no known natural enemies in New Zealand, although ''Acroclisoides'', a genus containing a species known to hyperparasitise ''T. basalis'' in Australia, is known to be present in New Zealand.

Distribution

''Trissolcus basalis'' is considered to be an effective biocontrol agent in New Zealand, Australia, and the United States, all places where it was deliberately introduced. In 1949 ''T. basalis'' was released in New Zealand in an effort to control damage caused to crops including sweet corn and green beans by ''

''. Over 48,000 parasitoids were reared from a shipment of between 200 and 300, and these were released at Awanui, Kaitaia, Paihia, Kawakawa, Whangarei, New Plymouth and Te Kaha (Bay of Plenty).

References

{{Taxonbar, from=Q14079847 Parasitic wasps Insects described in 1858 Platygastridae