Death from below: the first video of a parasitic wasp attacking caterpillar underwater

Named after fictional monster Godzilla, a parasitic wasp becomes the first observed and filmed to dive underwater for several seconds, in order to attack and pull out caterpillar hosts, so that it can lay its eggs inside them before releasing them back in the water.

A very few species of parasitoid wasps can be considered aquatic. Less than 0.1% of the species we know today have been found to enter the water, while searching for potential hosts or living as endoparasitoids inside of aquatic hosts during their larval stage.

Within the subfamily Microgastrinae (family Braconidae), only two species have previously been recorded to be aquatic, based on their parasitism of aquatic caterpillars of moths. However, none has been known to actually dive in the water.

Recently, during their research work in Japan, Dr. Jose Fernandez-Triana of the Canadian National Collection of Insects and his team found and recorded on camera the first microgastrine parasitoid wasp that dives underwater for several seconds, in order to attack and pull out caterpillar hosts, so that it can lay its eggs inside them before releasing them back in the water.

Interestingly, the wasp, which was described as a new to science species in the open-access, peer-reviewed scientific Journal of Hymenoptera Research, was given the awe-striking name Microgaster godzilla, because its emergence out of the water reminded the scientists of the Japanese iconic fictional monster Godzilla.

In the video, the female wasp can be seen walking over floating plants as it searches for hosts, specifically larvae of the moth species Elophila turbata, which constructs a portable case from fragments of aquatic plants and lives inside it near the water surface. Once the wasp finds one of those cases, it first probes it repeatedly with its antennae, while moving around. Eventually, it forces the larvae to come out of the case and parasitizes it by quickly inserting its ovipositor. In some cases, the wasp has to submerge completely underwater for several seconds, in order to find and pull the caterpillar out of its case. To do this, the species has evolved enlarged and strongly curved tarsal claws, which are thought to be used to grip the substrate as it enters the water and looks for hosts.

A female wasp Microgaster godzilla seeks out a moth caterpillar, dives in the water and pulls it out of its case, in order to parasitize it by quickly inserting its ovipositor.
Video by Dr. Jose Fernandez-Triana

As for the curious choice of name for the new species, Dr. Jose Fernandez-Triana explains:

“The reasons why we decided to use the name of Godzilla for the wasp species are interesting. First, being a Japanese species, it respectfully honours 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 remakes afterwards. It has become one of the most recognizable symbols of Japanese popular culture worldwide. Second, the wasp’s parasitization behaviour bears some loose resemblance to the kaiju character, in the sense that the wasp suddenly emerges from the water to parasitize the host, similar to how Godzilla suddenly emerges from the water in the movies. Third, 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 an adult moth. As you can see, we had biological, behavioural and cultural reasons to justify our choice of a name. Of course, that and having a bit of fun, because that is also an important part of life and science!”

Beyond unusual behaviours and funny names, Dr. Fernandez-Triana wants to emphasize the importance of multidisciplinary work and collaboration. The team that published this paper got to know each other at an international meeting devoted to biological control (The 5th International Entomophagous Insects Conference in Kyoto, Japan, 2017). 

“I was very impressed by several presentations by Japanese grad students, which included video recordings of parasitoid wasp biology. As a taxonomist, I am always impressed with the quality of research done by colleagues in other fields. In this case, we saw an opportunity to combine our efforts to study the wasp in detail and, when we found that it was a new species, we described it together, including adding the filmed behaviour to the original description. Usually, taxonomic descriptions of parasitoid wasps are based on dead specimens, with very few details–often none–on its biology. Thanks to my biocontrol colleagues, we could add more information to what is known about the new species being described. Hopefully we can continue this collaboration and combined approach for future studies”.

Original source:

Fernandez-Triana J, Kamino T, Maeto K, Yoshiyasu Y, Hirai N (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. https://doi.org/10.3897/jhr.79.56162

Journal of Hymenoptera Research links Crocodile Dundee, Toblerone, Game of Thrones & Alien

A myriad of species and genera new to science, including economically important wasps drawing immediate attention because of their amusing names and remarkable physical characters, in addition to work set to lay the foundations for future taxonomic and conservation research, together comprise the latest 64th issue of Journal of Hymenoptera Research (JHR).

The species Qrocodiledundee outbackense

Two genera (Qrocodiledundee and Tobleronius) named after the action comedy Crocodile Dundee and the chocolate brand Toblerone are only a couple of the 14 new genera from the monograph of the microgastrine wasps of the world’s tropical regions, authored by Dr Jose Fernandez-Triana and Caroline Boudreault of the Canadian National Collection of insects in Ottawa. In their article, the team also describes a total of 29 new species, where five of them carry the names of institutions holding some of the most outstanding wasp collections.

Another curiously named species of microgastrine wasp described in the new JHR issue, is called Eadya daenerys in reference to Daenerys Targaryen, a fictional character known from the best-selling book series A Song of Ice and Fire by George R. R. Martin, and the blockbuster TV show Game of Thrones. Discovered by University of Central Florida‘s Ryan Ridenbaugh, Erin Barbeau and Dr Barbara Sharanowski as a result of a collaboration between biocontrol researchers and taxonomists, the new species might not be in control of three dragons, nor a ruler or protector of whole nations. However, by being a potential biocontrol agent against a particular group of leaf beetle pests, it could spare the lives of many eucalyptus plantations around the world.

The species Tobleronius orientalis

Furthermore, a wasp named Dolichogenidea xenomorph, which parasitises other eucalyptus pests, is also named after a character from a sought-after franchise. The scriptwriters of the horror sci-fi movie series Alien are thought to have been thinking of parasitic wasps when they came up with the character Xenomorph, remind authors Erinn Fagan-Jeffries, Dr Steven Cooper and Dr Andrew Austin. Additionally, the team from University of Adelaide and the South Australian Museum point out that the species name translates to ‘strange form’ in Greek, which perfectly suits the characteristic remarkably long ovipositor of the new wasp.

The species Eadya daenerys

In another paper of the same journal issue, Dr. Jean-Luc Boevé, Royal Belgian Institute of Natural Sciences, Diego Domínguez, Universidad Técnica Particular de Loja, Ecuador, and Dr David Smith, Smithsonian’s National Museum of Natural History, USA, publish an illustrated list of the wasp-related sawflies, which they collected from northern Ecuador a few years ago. They also provide a checklist of the country’s species.

In conclusion, the fifth paper, authored by Serbian scientists Dr Milana Mitrovic Institute for Plant Protection and Environment, and Prof Zeljko

The species Dolichogenidea xenomorph

Tomanovic, University of Belgrade, studies ways to extract DNA from dry parasitoid wasps from the natural history archives decades after their preservation. In their work, they make it clear that such projects are of great importance for future taxonomic and conservation research, as well as agriculture.

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The open access Journal of Hymenoptera Research is published bimonthly by the scholarly publisher Pensoft on behalf of the International Society of Hymenopterists.

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Original sources:

Boeve; J, Dominguez D, Smith D (2018) Sawflies from northern Ecuador and a checklist for the country (Hymenoptera: Argidae, Orussidae, Pergidae, Tenthredinidae, Xiphydriidae). Journal of Hymenoptera Research 64: 1-24. https://doi.org/10.3897/jhr.64.24408

Ridenbaugh RD, Barbeau E, Sharanowski BJ (2018) Description of four new species of Eadya (Hymenoptera, Braconidae), parasitoids of the Eucalyptus Tortoise Beetle (Paropsis charybdis) and other Eucalyptus defoliating leaf beetles. Journal of Hymenoptera Research 64: 141-175. https://doi.org/10.3897/jhr.64.24282

Fagan-Jeffries EP, Cooper SJB, Austin AD (2018) Three new species of Dolichogenidea Viereck (Hymenoptera, Braconidae, Microgastrinae) from Australia with exceptionally long ovipositors. Journal of Hymenoptera Research 64: 177-190. https://doi.org/10.3897/jhr.64.25219

Boeve; J, Dominguez D, Smith D (2018) Sawflies from northern Ecuador and a checklist for the country (Hymenoptera: Argidae, Orussidae, Pergidae, Tenthredinidae, Xiphydriidae). Journal of Hymenoptera Research 64: 1-24. https://doi.org/10.3897/jhr.64.24408

Mitrovic M, Tomanovic Z (2018) New internal primers targeting short fragments of the mitochondrial COI region for archival specimens from the subfamily Aphidiinae (Hymenoptera, Braconidae). Journal of Hymenoptera Research 64: 191-210. https://doi.org/10.3897/jhr.64.25399

Ottawa confirmed as the biodiversity hotspot for a subfamily of wasps in North America

What usually comes to mind when speaking about biodiversity hotspots are tropical regions, pristine areas and magnificent forests. Meanwhile, it is quite rare that a city in a temperate zone is considered significant in terms of biodiversity, much less mentioned as a hotspot. Yet, the city of Ottawa together with its surroundings, despite having population surpassing 1 million people, is now confirmed to be the locality in North America with the most recorded species of braconid wasps in the subfamily Microgastrinae, a group of parasitic insects that attack caterpillars and play an important role in the natural biocontrol of agriculture and forestry pests.

A study published in ZooKeys reports 158 species within 21 different genera of Microgastrinae for Ottawa. “To put this into perspective,” says Dr. Jose Fernandez-Triana, affiliated with the Canadian National Collection of Insects and lead author of the paper, “if Ottawa (a relatively small area of less than 7,800 km2) would be considered as a country itself, its species total would rank 17th among all countries in the world.”

image-3-sathon-cinctiformisThere are close to 200 species of microgastrine wasps known from Canada and around 350 – from North America. Thus, the fauna in Ottawa equals to three quarters of the total recorded for the entire country, and almost half of all species in the Nearctic region. In fact, the diversity in the Canadian capital represents by far the highest number of species ever recorded for a locality in North America, a consequence of the city being a transition from an eastern deciduous forest biome to a boreal biome, with small areas of unusual habitats like dunes, alvars, floodplains and bogs.

Based on the analysis of almost 2,000 specimens, collected between 1894 and 2010, and housed in the Canadian National Collection of Insects, the paper also reports two new species for North America and two additional species records for Canada and Ontario, as well as dozens of new additions to the regional fauna. Seasonal distribution showed several peaks of activity, in spring, summer, and early fall.

The study highlights the incredible diversity of parasitoid wasps and how much remains to be discovered, even in temperate areas and/or city environments. “It is possible that southern localities in North America are eventually found to be more diverse than Ottawa,” notes Dr. Fernandez-Triana. “But for that to happen one would need to find an area that has a variety of habitats and has also been thoroughly sampled over the years, with thousands of specimens available for study.”

“In the meantime,” jokes the scientist, “the citizens of the Canadian capital will have the bragging rights in North America, at least for microgastrine wasp diversity.”image-2-dolichogenidea-cacoeciae

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Original source:

Fernandez-Triana J, Boudreault C, Buffam J, Mclean R (2016) A biodiversity hotspot for Microgastrinae (Hymenoptera, Braconidae) in North America: annotated species checklist for Ottawa, Canada. ZooKeys 633: 1-93. https://doi.org/10.3897/zookeys.633.10480