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| Microgaster godzilla Fernandez-Triana & Kamino in Fernandez-Triana, Kamino, Maeto, Yoshiyasu & Hirai, 2020. DOI: 10.3897/jhr.79.56162 |
Abstract
A new species of Microgastrinae (Hymenoptera: Braconidae) parasitoid wasp, Microgaster godzilla Fernandez-Triana & Kamino, is described from Japan. From a biological and morphological perspective this is a very unusual species. It represents only the third known microgastrine to be aquatic, and the first one to be found entering the water. The female wasp searches for its hosts, aquatic larvae of Elophila turbata (Lepidoptera: Crambidae), mostly by walking over floating plants, but occasionally diving underwater for several seconds to force the larva out of its case, when it is quickly parasitized (parasitization was always observed above water). The unique searching behaviour of M. godzilla as well as its parasitization of aquatic larvae was filmed and it is presented here. The wasp has simple tarsal claws, which are elongate and strongly curved, similar to those found in the related genus Hygroplitis; they seem to represent an adaptation for gripping to the substrate when entering the water. The new species is described based on morphological, molecular (DNA barcoding), biological and ethological data. Additionally, we provide detailed diagnoses to recognize M. godzilla from all other described species of Microgaster and Hygroplitis in the Palearctic, Nearctic and Oriental regions.
Keywords: aquatic parasitoid, biology, Lepidoptera, Microgastrinae, Nearctic, Oriental, Palearctic, parasitoid behaviour, taxonomy
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| Figure 1. Microgaster godzilla, female holotype. A habitus dorsal B habitus lateral C wings D head, frontal E details of antenna F head and mesosoma, lateral G head and mesosoma, dorsal. |
Microgaster godzilla, Fernandez-Triana & Kamino, sp. nov.
Diagnosis: Among all described species of Microgaster this species can be distinguished because of its unique combination of morphological characters. Color patterns are distinctive, especially having all legs almost entirely yellow (only apical 0.1 of metafemur, apical 0.3 of metatibia and metatarsus are dark brown to black), tegula dark brown, pterostigma brown, and metasoma dorsally with T1–T2 black and T3+ orange-yellow. Very few Microgaster species have all coxae yellow, and then the color of the tegula and/or metasoma dorsally is usually different. Beyond color, the combination of flagellomeres with relatively distinct setae (bristly), eyes convergent ventrally, face dull due to transverse, rugose sculpture (including indication of vermiculate rugosities towards sides), notauli barely marked by impression or sculpture (and overall sculpture of anteromesoscutum with fine and relatively shallow punctures), scutellar disc mostly smooth, mesopleuron without strong crenulated sulcus, T2 and T3 about same length, T3+ smooth, all tarsi with last segment enlarged, and large but simple tarsal claws are also of diagnostic value. Microgaster godzilla shares some features with the described species of Hygroplitis, most of which also have light-coloured legs, including all coxae in many species, large tarsal claws, and last segments of tarsi enlarged. However, most Hygroplitis species have the body depressed, notauli are strongly marked, antennae have three rows of placodes and the mesopleuron has a strong, crenulated sulcus.
Although there is no available key that covers all described Hygroplitis and Microgaster, we found that all Palearctic, Nearctic and Oriental species previously described in those two genera differ from the diagnosis provided above for M. godzilla by at least one (usually more) characters. To facilitate future work on the genus we provide one-to-one comparisons of M. godzilla with every other previously described species of those two genera in the biogeographical regions relevant to the new species (see Suppl. material 5 for detailed comparisons).
Distribution: The species has only been collected in the prefectures of Osaka and Kyoto in Honshu, Japan.
Etymology: The species is named after Godzilla (Japanese: ゴジラ, Hepburn: Gōjira), a fictional monster (kaiju) that became an icon after the 1954 Japanese film of the same name and many films afterwards. The wasp name is intended to respectfully honour one of the most recognizable symbols of Japanese popular culture worldwide. The wasp’s parasitization behaviour bears some loose resemblance to the kaiju character, in the sense that the wasp (after diving underwater to search for its host, a moth caterpillar) suddenly emerges from the water (to parasitize the host), similar to how Godzilla suddenly emerges from the water in the movies. Additionally, Godzilla has sometimes been associated, albeit in different ways, with Mothra (Japanese: モスラ, Hepburn: Mosura) another kaiju that is typically portrayed as a larva (caterpillar) or adult moth.
Jose Fernandez-Triana, Tetsuyuki Kamino, Kaoru Maeto, Yutaka Yoshiyasu and Norio Hirai. 2020. 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. 79: 15-26. DOI: 10.3897/jhr.79.56162