Professor Norio Hirai and a graduate student Mr. Tetsuyuki Kamino at Environmental Entomology and Zoology, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, and the professor’s research team found an unusual wasp at OPU campus in Japan which dives underwater to parasitize its caterpillar host. From the results of collaboration with Canadian National Collection of Insects and Kobe University, the wasp was identified as a new species and named after Godzilla, a fictional monster. The wasp’s parasitization behaviour bears some loose resemblance to the kaiju character.

Microgaster godzilla

The order Hymenoptera comprises relatively very few aquatic species, 0.13% of all described Hymenoptera species recognized so far. Only two species had been recorded until now as being aquatic, in both cases the wasp are parasitizing lepidopteran larvae which are aquatic. However, none of them has been known to actually dive in the water.

And his team found and recorded on camera the first microgastrine parasitoid wasp that dives underwater for several seconds. In the video, a female wasp Microgaster godzilla seeks out a moth caterpillar with its antennae（Video）, and dives in the water to pull it out of the water, in order to parasitize the caterpillar by quickly inserting its ovipositor（Video）. To do this, the wasp has simple tarsal claws, which are elongate and strongly curved that allows hymenopterans to grip the substrate when entering the water looking for hosts.

This research was published in the online version of Journal of Hymenoptera Research, International Society of Hymenoptera, on October 30, 2020.

Paper Information

Microgaster godzilla (Hymenoptera, Braconidae, Microgastrinae), an unusual new species from Japan which dives underwater to parasitize its caterpillar host (Lepidoptera, Crambidae, Acentropinae)

• Journal of Hymenoptera Research (Pensoft Publishers Website)

Click “Download file” to download videos from next links.

• A female wasp Microgaster godzilla seeks out a moth caterpillar with its antennae.
• Parasitize the caterpillar by quickly inserting its ovipositor.

Acknowledgements

This study was supported in part by a grant from JSPS KAKENHI (No. 19H00942) and by project 3199 “Systematics of beneficial arthropods in support of resilient agroecosystems”, from Agriculture and Agri-Food Canada. Grateful to Canadian National Collection of Insects, the Panasonic Corporation in Kadoma City, and Kyoto Botanical Gardens.

Contribution to SDGs

15: Life on land

Related information

• Death from below: the first video of a parasitic wasp attacking caterpillar underwater (PHYS.ORG Webpage)
• New Species of Parasitizing Wasp Filmed Diving to Stab Egg into Caterpillar (IFLScience webpage)