Trissolcus japonicus | |
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Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | Insecta |
Order: | Hymenoptera |
Family: | Scelionidae |
Genus: | Trissolcus |
Species: | T. japonicus
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Binomial name | |
Trissolcus japonicus (Ashmead, 1904)
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Synonyms[1] | |
Trissolcus halyomorphae Yang et al, 2009 |
Trissolcus japonicus, the samurai wasp, is a parasitoid wasp species in the family Scelionidae, native to east Asia but now found in Europe, North America, and Chile.[2][3] It is chiefly known for parasitizing Halyomorpha halys (brown marmorated stink bug).[4] It deposits eggs into the eggs of the stink bug, and as the wasp larvae develop, they kill the stink bug eggs. A single adult wasp emerges from each stink bug egg.[5]
Trissolcus japonicus was originally described by American entomologist William Harris Ashmead in 1904,[6] and transferred to the genus Trissolcus in 1968.[7] All species within the genus Trissolcus are egg parasitoids of Pentatomoidea (stink bugs and their allies).[8] Trissolcus halyomorphae was in use from 2009, but has since been classified as a junior synonym of Trissolcus japonicus.[9][10]
Trissolcus japonicus adults are small black wasps with orange and black legs and antennae. The adult samurai wasp is 1–2 millimetres (3⁄64–5⁄64 in) in length. The size of the wasp depends on the size of the host egg from which it emerged.[11] It does not sting people.[12]
The samurai wasp is native to Eastern Asia, including China, Japan, Korea, and Taiwan.[13]
In 2014, two adventive populations were found in the United States during surveys to identify which North American parasitoids might be attacking brown marmorated stink bug.[2][14] Subsequent genetic testing showed these wild populations were self-introduced: they were not related to each other, or to the laboratory strain of parasitoids housed in quarantine for biosafety testing since 2007.[15] An adventive European population was discovered during similar surveys in Switzerland in 2017.[16]
Trissolcus japonicus is currently the subject of biological control programs against the brown marmorated stink bug (BMSB) in the US, Europe, and New Zealand.[17] In the United States, it will likely take years for the wasps to build up large enough densities in the wild to have a measurable impact on BMSB populations, but efforts are under way to augment wild populations with laboratory reared specimens.[18][19] Recent redistribution efforts of Trissolcus japonicus in New York State also engages Citizen Science project participants in reducing urban BMSB populations.[20] In New Zealand, host range testing has shown it attacks the endemic alpine shield bug (Hypsithocus hudsonae) in laboratory tests when a parasitoid is confined with an egg mass.[21]
In its native range, the samurai wasp is able to complete up to 10 generations per year, while its primary host, brown marmorated stink bug, completes up to 2.[13] Female wasps lay on average 42 eggs, preferring to oviposit into host eggs younger than 3 days old. Males hatch first and mate with their sisters.[22]