parasitoid wasps

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

Total of 21 new parasitoid wasps following the first ever revision of their genus

As many as twenty-one species of parasitoid wasps are described as new to science, following the first ever revision of their genus since its establishment back in 1893.

The study simultaneously updates the count of species within the genus (Chromoteleia) to 27 in total, produces a systematic revision of the world’s representatives of this group of wasps, expands their biogeographic knowledge, and clarifies their generic concept.

The monograph is published in the open access journal ZooKeys by a team of US and Canadian scientists, led by Hua-yan Chen, graduate student at the Ohio State University.

The wasps in the genus Chromoteleia are easily distinguished thanks to their large size in combination with their vivid colouration. Compared to other species in the family of platygastrid wasps, which normally measure merely 1 – 2 mm in length, the species in the studied genus range between 3 and 9 mm. Their uncommonly large, robust and elongated bodies is why the scientists assume that these wasps likely parasitise the eggs of orthopterans, such as grasshoppers, crickets and katydids.

A focal point in the study is the intriguing distribution of the wasps. While the genus is widespread throughout continental Mesoamerica, Central America and South America, and its distribution ranges from the Mexican state of Jalisco in the north all the way to Itapúa Department in Paraguay and Paraná in southern Brazil, the species C. congoana is a lone representative of the genus in Africa.

*The ‘lone’ African representative of the genus, Chromoteleia congoana.*

While dispersal from South America to Africa has been observed in the past in another genus of parasitoid wasps (Kapala), the scientists are not willing to reject the possibility of Chromoteleia wasps having been widely distributed across the Old World during a previous geological epoch. Such phenomenon, also known as a relict population, would not mean that the wasp group has subsequently ‘conquered’ the Neotropics and current species inhabiting the New World are rather remainders of once widespread insects.

To conclude their findings, the scientists examined specimens hosted in collections at twenty natural history institutions from around the globe, including the American Entomological Institute; American Museum of Natural History; Bernice P. Bishop Museum; California Academy of Sciences; Canadian National Collection of Insects; California State Collection of Arthropods; Florida State Collection of Arthropods; Instituto Alexander von Humboldt; Illinois Natural History Survey; Kansas University’s Natural History Museum; Museo del Instituto de Museo del Instituto de Zoologia Agricola; Museum National d’Histoire Naturelle; Museu Paraense Emílio Goeldi; Lund Museum of Zoology at Lund University; Triplehorn Insect Collection at the Ohio State University; South African Museum; Texas A&M University’s Insect Collection; Bohart Museum of Entomology; University of Colorado; and Smithsonian National Museum of Natural History.

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Original source:

Chen H-y, Talamas EJ, Valerio AA, Masner L, Johnson NF (2018) Revision of the World species of the genus Chromoteleia Ashmead (Hymenoptera, Platygastridae, Scelioninae). ZooKeys 778: 1-95. https://doi.org/10.3897/zookeys.778.25775

New parasitoid wasp likely uses unique saw-like spines to break out of its host body

About the size of a sesame seed, a new species of wasp from Costa Rica, named Dendrocerus scutellaris, has elaborate branched antennae that could be used for finding mates. Or hosts.

The new insect is described by PhD candidate Carolyn Trietsch, Dr. István Mikó and Dr. Andrew Deans of the Frost Entomological Museum at Penn State, USA, together with Dr. David Notton of the Natural History Museum in London, UK. Their study is published in the open access Biodiversity Data Journal.

The wasp is a parasitoid, meaning that its larvae feed on a live host insect. There are two types of parasitoids: ectoparasitoids, which lay their eggs on or near the host, so that the hatchling larvae can attach to and feed on the insect from the outside; and endoparasitoids, which lay their eggs directly inside the host, so that the larvae can eat them from the inside out.

Unfortunately, to puzzle out the new wasp’s lifestyle, the researchers could only rely on specimens collected back in 1985, which had spent the past few decades stored in the collections of the Natural History Museum of London before being loaned to the Frost Museum at Penn State for research.

What can you learn about a wasp’s lifestyle from specimens that are over 30 years old? Even though the new species has never been observed in the wild, researchers managed to learn a lot by looking at the wasps’ morphology, concluding that the species is likely an endoparasitoid.

The larva of an endoparasitoid wasp needs a safe place to develop and mature, so when it is done feeding on its host, it may stay inside the host’s body where it can develop undisturbed. Once it is fully grown, the adult wasp either chews or pushes its way out, killing the host if it isn’t already dead.

Unlike its close relatives, the new species does not have pointed mandibles for chewing. Instead, it has a series of spines along its back. While the wasp is emerging, it may rub these spines against the host and use them like a saw to cut open the body. Once emerged, it flies off to mate and continue the cycle.

“While their lives may sound gruesome, parasitoid wasps are harmless to humans and can even be helpful,” explain the scientists. “Depending on the host they parasitize, parasitoids can benefit agriculture by controlling pest insects like aphids that damage crops.”

It is currently unknown what the new species feeds upon, but naming the species and bringing it to attention is the first step in learning more about it.

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Original source:

Trietsch C, Mikó I, Notton D, Deans A (2018) Unique extrication structure in a new megaspilid, Dendrocerus scutellaris Trietsch & Mikó (Hymenoptera: Megaspilidae). Biodiversity Data Journal 6: e22676. https://doi.org/10.3897/BDJ.6.e22676

Of Star Trek, Mark Twain and helmets: 15 new species of wasps with curious names

A total of fifteen new species of parasitic wasps have been described from across the Neotropical region. Apart from belonging to a peculiar group of wasps distinct with large and elongated bodies, the new insects also draw attention with the curious names they have been formally assigned with.

Among them, there are species named after characters from the television series Star Trek and Mark Twain’s The Prince and the Pauper, and five wasps bearing species names all translating to ‘helmet’. The study, conducted by graduate student Katherine C. Nesheim and Dr. Norman F. Johnson, both affiliated with the Ohio State University, USA, and Dr. Lubomír Masner, Agriculture and Agri-Food Canada, is published in the open access journal ZooKeys.

The larvae of the studied wasps parasitise the eggs of lanternflies and planthoppers. These species inhabit exclusively the Neotropical region, with their range stretching from the Isthmus of Tehuantepec in the north to Misiones in southern Paraguay. Despite being quite abundant in the region, these insects have remained under-researched until recently.

One of the newly discovered wasp is named Phanuromyia odo, where the species name odo refers to the Star Trek: Deep Space Nine fictional character of the same name. In the popular sci-fi television series, Odo belongs to a species of shapeshifters called Changelings. The reason for the scientists to associate the parasitoid with the character is the spectacular variability observed within the insect species. In fact, it was this peculiarity that, at some point, led the entomologists believe they were dealing with two separate species.

The authors do not make a clear statement that the new species P. pauper has a name inspired by the famous novel The Prince and the Pauper by Mark Twain. Instead, they justify their choice with the fact that the species lacks a specific morphological feature – thus making it ‘poor’. On the other hand, the authors confirm that the new species called P. princeps is of ‘blue blood’ indeed, having its name derive from the other main character of the same book. Furthermore, both species are reported to look a lot like each other.

Among the curious names in the list of new species, there are also five wasps whose scientific names all translate to ‘helmet’ in three different languages – Greek, Latin and Old Norse. The reason behind is that they have unusually large heads, which reminded the scientists of a “knight wearing a helmet”. Likewise, a related species received a name that in Latin means ‘wearing a hood’.

There is also a species, whose name means ‘having long hair’, and another called ‘constellation’ in Latin.

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Original source:

Nesheim KC, Masner L, Johnson NF (2017) The Phanuromyia galeata species group (Hymenoptera, Platygastridae, Telenominae): shining a lantern into an unexplored corner of Neotropical diversity. ZooKeys 663: 71-105. https://doi.org/10.3897/zookeys.663.11554

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.”

There 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.”

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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