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 discovered in the eggs of leaf-rolling weevils in Africa

A new species of parasitic wasp has been obtained from the eggs of weevils, associated with bushwillows, collected and identified by Dr. Silvano Biondi. Given the tiny insect from northeastern Gabon is the first record of its genus for West-Central Africa, the researchers Dr. Stefania Laudonia and Dr. Gennaro Viggiani, both affiliated with Italy’s University of Naples Federico II, decided to celebrate it by assigning the species a name that refers to the continent. Their team has published the findings in the open access journal ZooKeys.

Named Poropoea africana, the new species belongs to a large worldwide group of wasps well-known as egg parasitoids of leaf-rolling weevils. Using characteristically long ovipositors, they lay their own eggs in the eggs of the hosts, found in cigar-like rolls.

The new wasp measures less than 2 mm. It can be distinguished from related species by a number of characters, including the structure of the antennae, and the front and hind legs, which are more robust than the middle ones. The latter, which is a unique trait for the genus, seems to be an adaptation to host parasitisation, where the modified legs likely support the body and improve the propulsive efficiency of the ovipositor.

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Original source:

Laudonia S, Viggiani G, Biondi S (2017) A new species of Poropoea Foerster from Africa (Hymenoptera, Chalcidoidea, Trichogrammatidae). ZooKeys 658: 81-87. https://doi.org/10.3897/zookeys.658.11501

Hollywood star Brad Pitt shares a name with a new wasp species from South Africa

Not only did an international research team discover two new endoparasitic wasp species in South Africa and India, and significantly expanded their genera’s distributional range, but they also gave a celebrity name to a special one of them.

While thinking of a name for the new wasp, Dr Buntika A. Butcher, Chulalongkorn University, Thailand, recalled her long hours of studying in her laboratory right under the poster of her favourite film actor. This is how a parasitic wasp from South Africa was named after Hollywood star Brad Pitt. The researchers have published their findings in the open access journal ZooKeys.bradpitti wasp img2

The new wasp species, called Conobregma bradpitti, belongs to a large worldwide group of wasps parasitising in moth or butterfly caterpillars. These wasps lay their eggs into a host, which once parasitised starts hardening. Thus, the wasp cocoon can safely develop and later emerge from the ‘mummified’ larva. Despite their macabre behaviour, many of these wasp species are considered valuable in agriculture because of their potential as biological control.

Brad Pitt’s flying namesake is a tiny creature measuring less than 2 mm. Its body is deep brown, nearly black in colour, while its head, antennae and legs are brown-yellow. The wings stand out with their much brighter shades.

Interestingly, the wasp with celebrity name unites two, until now, doubtful genera. Being very similar, they had already been noted to have only four diagnostic features that set them apart. However, C. bradpitti shared two of those with each. Thus, the species prompted the solution of the taxonomic problem and, as a result, the two were synonymised.

In their paper, the authors from Chulalongkorn University, Thailand and the University of Calicut, India, also describe another new species of parasitic image 3wasp. It is the first from its subtribe spotted in the whole of India, while its closest ‘relative’ lives in Nepal.

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Original source:

Butcher BA, Quicke DLJ, Shreevihar S, Ranjith AP (2016) Major range extensions for two genera of the parasitoid subtribe Facitorina, with a new generic synonymy (Braconidae, Rogadinae, Yeliconini). ZooKeys 584: 109-120. doi: 10.3897/zookeys.584.7815

Seventy-four cuckoos in the nest: A new key to all North European cuckoo wasp species

Captivating with their bright, vivid and brilliantly metallic bodies, the cuckoo wasps are also fascinating with their curious lifestyle, which has given them this common name. However, in terms of their taxonomic grouping, they have been quite problematic due to similarities between species and a wide range of variations within them.

To shed light on the issue, an international research team, led by MSc Juho Paukkunen, Finnish Museum of Natural History, Helsinki, provides descriptions and illustrations of all 74 species found in the Nordic and Baltic countries, including one new, in their recent publication in the open-access journal ZooKeys.

Beautiful in appearance, the cuckoo wasps penetrate the nests of unrelated solitary wasps and solitary bees to lay their eggs, similar to how a cuckoo bird does in songbird nests. With their armoured bodies and the ability to curl up into a tight ball the cuckoo wasps are well-defended against the owners of the nests and their stings and jaws. At the larval stage, they take advantage of their hosts by either parasitising them or stealing their food, eventually killing the host’s offspring.

Within the Nordic representatives of the family there are an exceptionally large number of red-listed and endangered species. This is one of the reasons why the authors intend to trigger more interest among their fellow entomologists about these curious wasps. They have compiled all relevant information concerning their distribution, abundance, habitats, flight season and host species. The authors have tried to keep their identification key as comprehensive and concise as possible, by singling out the essential information on diagnostic characters.

In the present study, the researchers describe a new species, called Chrysis borealis, which can be translated as ‘Northern’ cuckoo wasp. Although the male and female individuals are very similar, there is a significant variation in the colouration within the species. It is especially noticeable between the specimens collected from the northern localities and those from the southern ones. For instance, while the middle section of the body in southern specimens is either bright blue or violet with a greenish shimmer, in northern individuals it is nearly black, turning to greenish or golden green at the periphery.

The varying shades within a certain species are quite common among the cuckoo wasps. While it is often that distinctive colouration among other wasps and insects indicates their separate origin and therefore, taxonomic placement, within the emerald family it can be a mere case of habitat location with the northern populations typically darker.

Such tendencies often lead to doubts such as the one the authors have faced regarding their new species. It has been suggested that the Northern cuckoo wasp is in fact yet another variation of the very similar C. impressa, which is generally slightly brighter in colour, but at the same time distributed in warmer localities. However, using DNA sequence information and morphometric analysis, the team shows that there are enough consistent differences to separate them as distinct species, although they are defined as evolutionarily young siblings.

With their research the authors intend to provide a basis for further and more detailed studies on the distribution, biology and morphology of the North European representatives of these intriguing wasps.

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Original source:

Paukkunen J, Berg A, Soon V, Odegaard F, Rosa P (2015) An illustrated key to the cuckoo wasps (Hymenoptera, Chrysididae) of the Nordic and Baltic countries, with description of a new species. ZooKeys 548: 1-116. doi: 10.3897/zookeys.548.6164

Call for arms and stings: Social wasps use alarm pheromones to coordinate their attacks

Humans might know them as vicious stingers, but yellow jacket wasps also impress with their vigorous protection over their young. To resolve the mystery around their complex defensive behavior, a Canadian research team, led by Dr. Sean McCann, Simon Fraser University, have used simple components to develop and construct a device that consequently helped them to locate the species-specific alarm pheromones in three wasp groups. The insects use the emission of these substances to mark the enemy threatening their colonies and then join forces against it. The study is published in the open-access Journal of Hymenoptera Research.

Social insects invest a lot of work and resources in their colonies, working together to raise large numbers of larvae. Because their nests contain so many protein-rich, yet helpless young, they have evolved elaborate defence mechanisms to protect them.

One way the social wasps have found to increase the efficiency of their defence is through chemical signals, called alarm pheromones, which are used to rouse the colony to action and mark intruders for attack. As a result, the coordinated attack of a large colony of yellow jackets can drive even large predators away from the nest. Several social wasp alarm pheromones have been discovered, and most of these have been detected in the venom sacs of the wasps. Nonetheless, the process of finding out which chemicals are involved requires many experiments in the field in addition to chemical analysis.

“We developed a new and standardized method to evaluate alarm pheromone activity in yellowjackets and other social wasps that is inexpensive and easy to use. The device we constructed uses off-the-shelf components, and consists of a pair of black targets enclosing a pair of microphones,” explain the authors.

“A test substance and a control can be applied to each target, and then a stereo audio file is recorded at the nest site,” they further comment. “When wasps hit the black targets, it makes a percussive sound, almost like a drum. The resulting stereo file is then split and analysed with an open-source software program to count the number of strikes received by the treatment and control targets.”

The advantage of this system is its ease of use, low cost, and the ability to use rapid automated counting, which saves a lot of time compared to other methods.

The scientist have used this new method to figure whether three species of yellow jackets (the western yellow jacket, the common yellow jacket and the German yellow jacket) have alarm pheromones, and whether each species is able to recognize each of the alarm pheromones of the rest.

“We found evidence for alarm pheromones in all three species, and that each species recognizes and responds to the other species’ alarm pheromones in similar ways,” say the researchers. “We conclude that the chemical messages produced by these three yellow jacket species must be very similar.”

“It makes sense that wasps can recognize the alarm pheromones of other species, because it would be advantageous to be able to detect a pheromone-marked predator that has attacked other wasps nearby and start stinging it to drive it away before it finds their own colony,” conclude the authors.

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Original source:

McCann S, Moeri O, Jimenez SI, Scott C, Gries G (2015) Developing a paired-target apparatus for quantitative testing of nest defense behavior by vespine wasps in response to con- or heterospecific nest defense pheromones. Journal of Hymenoptera Research 46: 151-163. doi: 10.3897/JHR.46.6585.

To kill a wolf spider: Further observation of a spider wasp larva growing on its host

Having been attacked, paralysed and implanted with a wasp egg to its belly, a wolf spider carries on with its life fully mobile and active. At least, until it is time for the larva to reach out for its first solid meal at a certain development stage. The present study, conducted by a Brazilian team of scientists, led by PhD student Hebert da Silva Souza, Universidade Estadual de Campinas, Sao Paulo, and published in the open-access Journal of Hymenoptera Research, follows the entire cycle of larval development from the egg laying through the formation of a full-grown wasp.

The herein observed wasp species, called Paracyphononyx scapulatus, belongs to a well-known group of spider parasites, which after laying their eggs on a paralysed spider, let it recover and continue living fully mobile until the larvae are mature. However, little has been known about this curious behaviour of this wasp species in particular, since previous studies have already showed differences between the separate members of the genus.

To observe the whole cycle of the wasp larval development, the researchers caught a recently parasitised wolf spider and placed it in a plastic container.

While the larva grew and fed on the abdominal hemolymph, which is the analog to the blood in backboned creatures, its host did not show any peculiarities in its behaviour and even kept its routine being active at night and resting during the day. This is suggested to be attributed to the need of the larva to keep its host safe from predators, such as ants, which could otherwise eat the dead body.

However, ahead of its fifth and last development stage, the larva was seen to double its size and, in the morning, twenty days after the hatching of the egg, it killed its host and fully consumed it within the next forty-eight hours. Having left its host, the larva began to search for a place within the container to construct a cocoon, which took it sixteen hours. Thirty-two days later, a fully grown female wasp emerged.

In comparison, a relative of the observed spider wasp is known to manipulate its host’s behaviour, making it to enwrap itself and the larva in a cocoon-like silken structure so that it is protected while feeding. Yet, it is not certain whether the observed larva’s growth in captivity is not the reason why it had not induced similar behaviour.

In conclusion, the authors suggest that further investigation of the interaction between the two species could provide more information about the evolution of this kind of parasitism, which is likely to have developed independently among the wasp groups.

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Original source:

Souza HS, Messas YF, Masago F, dos Santos ED, Vasconcellos-Neto J (2015) Paracyphononyx scapulatus (Hymenoptera, Pompilidae), a koinobiont ectoparasitoid of Trochosa sp. (Araneae, Lycosidae). Journal of Hymenoptera Research 46: 165-172. doi: 10.3897/JHR.46.5833

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

Diggers from down under: 11 new wasp species discovered in Australia

After being mostly neglected for more than a hundred years, a group of digger wasps from Australia has been given a major overhaul in terms of species descriptions and identification methods. This approach has led to an almost 50% rise in the number of recognized species of these wasps on the continent. The study was published in the open access journal ZooKeys.

They call them with names like “Great Golden Digger” or “Great Black Wasp” in the US and there is a good reason behind it. However, some of these digger wasp species do not impress solely with their looks, but also with their wide range of distribution. Members of the wasp genusSphex can be found in almost every area of the world. Two researchers from the Museum für Naturkunde in Berlin, Thorleif Dörfel and Dr. Michael Ohl, have now reexamined the species diversity of Sphex in Australia.

More than a century has passed since the last revision of this group in the Down Under. Using pinned, dried individuals from museum collections all over the world, Dörfel and Ohl inspected over 900 specimens and recorded the morphological characters that they deemed most useful for species differentiation.

A very different lifestyle sets apart some species in the genus Sphex from the common idea that most people evoke on hearing the term “wasp”. Not being eusocial, each female constructs a separate, subterranean nest for their offspring, which is then filled with grasshoppers (or other insects, depending on the wasp species) that have been paralyzed by a sting as a food supply for the larvae. These wasps avoid contact with humans and generally do not show aggressive behavior toward us.

With 23 species known from Australia before this study, now the number has risen to 34. Most of these newly discovered species come from large quantities of material which had not been identified up to species level before. Dörfel and Ohl’s work also provides an up-to-date identification key, both in a regular and in an interactive form, that covers all known Australian species of the genus. Specifically designed to be easily usable and containing many helpful images, it can be utilized by anyone with even minimal prior training.

“Many insect groups are in urgent need of a revision or reclassification”, explained Thorleif Dörfel. “Our understanding of ecosystems depends on the ability to identify the species that are a part of them. The focus of this study was merely a single continent, but we are currently preparing a follow-up project in which we plan to examine representatives of this wasp genus from every major geographic area. Hopefully, this is going to help everybody who works on these animals, whether now or in another one hundred years.”

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Original source:

Dörfel TH, Ohl M (2015) A revision of the Australian digger wasps in the genus Sphex(Hymenoptera, Sphecidae). ZooKeys 521: 1-104. doi: 10.3897/zookeys.521.5995

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