Tag: parasitoid

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

New species of parasitic wasp named after ancient god of evil Set shows wicked behavior

Being able to manipulate its host’s behavior while growing inside of it, a new species of parasitic wasp seems to have deservedly received the name of the ancient Egyptian god of evil and chaos Set. Discovered in the southeastern United States, the new species, also called the crypt-keeper wasp, parasitizes crypt gall wasps, which in turn infest live oak. The research team led by Dr. Scott P. Egan of Rice University published their discovery in the open access journal ZooKeys.

Once parasitized, the crypt gall wasp cuts a hole through the gall it has built around itself, and plugs its head in it right before being killed. Meanwhile, the larva of the crypt-keeper wasp feeds, grows, and pupates on the insides of its host. As soon as it is ready to emerge as an adult, it takes a ‘shortcut’ out of the crypt gall straight through the head capsule of its prey, leaving chunks of exoskeleton behind in the ‘crypt’. The team has published a parallel paper (Weinersmith et al. 2017) documenting this manipulation and exploring the fitness benefit to E. set in the journal Proceedings of the Royal Society B.

To justify the comparison between the new wasp and Set, the scientists point out that the deity is said to have control on evil animals, such as hyenas and serpents. Furthermore, according to the ancient Egyptian mythology, he trapped his good-hearted brother Osiris in a crypt and killed him. Then, he chopped his body into small pieces and scattered them all over the world.

The new wasp, described under the name Euderus set belongs to a genus of approximately 77 species with a cosmopolitan distribution. The species is a tiny insect measuring between 1.2 and 2.3 mm in length, but under a microscope, it is one of the most colorful. Its colors are shiny metallic, varying from olive green to turquoise to iridescent blue, depending on lighting and age. Originally discovered near Inlet Beach, Florida, it has now been found across the U.S. Gulf coast, including sites in Georgia, Florida, Mississippi, Louisiana, and Texas.

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Original source:

Egan SP, Weinersmith KL, Liu S, Ridenbaugh RD, Zhang MY, Forbes AA (2017) Description of a new species of Euderus Haliday from the southeastern United States (Hymenoptera, Chalcidoidea, Eulophidae): the crypt-keeper wasp. ZooKeys 645: 37-49. https://doi.org/10.3897/zookeys.645.11117

The first long-haired ones: New wasp group proposed for 5 new species from India

Long accustomed to parasitising spider eggs, a large worldwide genus of wasps has as few as 24 known representatives in India. However, Dr. Veenakumari, ICAR-National Bureau of Agricultural Insect Resources, and her team have recently discovered five new species of these interesting wasps from different parts of the country. Because of their uniqueness and their strong resemblance to each other, as well to aid taxonomic studies they have been considered as constituting a group of their own. The discoveries and the suggestion of ‘the first long-haired ones’ species group are available in the open-access journal Deutsche Entomologische Zeitschrift.

Among the unique features that bring together the new five species, discovered by Drs. Veenakumari Kamalanathan, Prashanth Mohanraj and F. R. Khan, are the long hair-like structures along the margins of both of their wings. This is also the reason behind the authors’ choice of naming the proposed group adikeshavus, meaning ‘first one to have long hairs’ in Sanskrit.

Within this parasitic superfamily of wasps each group has been long accustomed to a specific host. The tribe to which the new five wasp species belong, for instance, is characterised by its exclusive preference for spider eggs. Parallel evolution accounts for the tiny wings of these wasps which allows them to slip through the silk strands of the egg sacs which are deposited in leaf litter by the spiders. Furthermore, all these species have a uniform length of 1 to 2 mm as a result of their getting used to parasitising relatively medium-sized spider eggs.

With over a thousand species supposed to exist in this genus the scientists suggest that their clustering into groups is a necessity to facilitate future studies.

The authors conclude that it is highly likely that this group of wasps will yield a much larger number of species of parasitoids attacking spider eggs in India.

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Original source:

Kamalanathan V, Mohanraj P, Khan FR (2015) ‘The adikeshavus-group’: A new species group of Idris Förster (Hymenoptera, Platygastridae) from India, with descriptions of five new species. Deutsche Entomologische Zeitschrift 62(2): 247-260. doi: 10.3897/dez.62.6219

Parasite vs. Invader: New endoparasitoid wasp can save the Dominican Republic economy

While biocontrol agents come in different shapes, often taking a lot of time for scientists to research, test and produce, natural ones always seem to be the better option. Now that Drs. Taveras and Hansson have discovered a new parasitoid wasp species in the Dominican Republic, they might have not only met the worst natural enemy for a widely spread invasive pest corrupting a large part of the essential pigeon pea crops. They are likely to have found a whole new field for investigation into the potential weapons against the eradicator of up to 76% of the essential crop. Their study is available in the open access Journal of Hymenoptera Research.

The find of this new gregarious endoparasitoid wasp, called Pediobius cajanus, is also the first time representative of this genus has been retrieved from the Asian fly. This invasive pest is estimated to destroy a huge part of the pigeon pea crops, a culture which is an essential food source for tropical America, a large part of the export and even has medicinal value. Therefore, the new species is very important not only in terms of the exploration of the biodiversity in Latin America, but also in economical sense.

Even when treated regularly with insecticides, the Asian fly manages to corrupt as much as 27% of the Dominican pigeon pea crops, a previous study shows. Although a precise figure of the damage cannot be provided due to large variations between localities and the impossibility of tracking the whole span of the pea cultivation areas, there is the case of the town of Rancho Los Vargas, Puerto Plata, where in 2012 the loss of the culture reached 76%.

On the other hand, the new wasp species was found to kill an average of 25% of the Asian fly larvae in the researched areas. In comparison, the previously known enemies of the pest are accountable for only 2%. This is why the scientists are now proposing the new species as a biocontrol agent.

In conclusion, the authors suggest that the parasitoid wasp is likely distributed across a much larger area. They believe that the new species could also be found over the entire island of Hispaniola, on neighbouring islands in the Caribbean and even in the tropical parts of the mainland in the Americas. Its record and distribution both call for a further investigation into the potential implementation of the wasp in controlling the Asian fly.

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Original source:

Taveras R, Hansson C (2015) Pediobius cajanus sp. n. (Hymenoptera, Eulophidae), an important natural enemy of the Asian fly (Melanagromyza obtusa (Malloch)) (Diptera, Agromyzidae) in the Dominican Republic. Journal of Hymenoptera Research 45: 41-54. doi: 10.3897/JHR.45.4964

Flickr and a citizen science website help in recording a sawfly species range expansion

Social network Flickr and citizen science website BugGuide have helped scientists to expand the known range of a rarely collected parasitic woodwasp, native to the eastern United States. Partially thanks to the two online photograph platforms, now the species’ distribution now stretches hundreds of miles west of previous records. Previously known from only 50 specimens mainly from the Northeast, now the species was discovered in the Ozark Mountains by researchers from the University of Arkansas. Their study is published it in the open access journal Biodiversity Data Journal.

Spurred on by the find, Michael Skvarla, a Ph.D. candidate at the university, contacted retired sawfly expert David Smith who alerted him to a hundred unpublished specimens housed in the United States National Entomology Collection at the Smithsonian, many of which were collected as bycatch in surveys that targeted invasive species like emerald ash borer andAsian longhorned beetle. Additional specimens from Iowa, Minnesota, and Manitoba, which also represent significant western range expansions, were found after users posted photos of the species on the social network Flickr and the citizen science website BugGuide.

“We used two resources – photos on social media and bycatch from large trapping surveys – which are often underutilized and I was really happy we could work both of them into the paper,” said Skvarla, the lead author. “This work highlights their utility, as well as the importance of maintaining biological collections like the U.S. National Collection and continuing to collect in undersampled regions like the Ozark Mountains.”

Parasitic woodwasps attack the immature stages of longhorned beetles, jewel beetles, and other woodwasps which bore into wood and have long fascinated entomologists because of this parasitoid nature, which is unique among woodwasps, and rarity in collections. The Arkansas specimens, which belong to the species Orussus minutus and motivated the initial research into the group, were collected as part of a larger survey of the insect fauna around the Buffalo National River.

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Original Source:

Skvarla, M.J., Tripodi, A., Szalanski, A., Dowling, A.P.G. 2015. New records of Orussus minutusMiddlekauff, 1983 (Hymenoptera: Orussidae) represent a significant western range expansion. Biodiversity Data Journal, 3: e35793. doi: 10.3897/BDJ.3.e5793