insect species

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

First Australian night bees recorded foraging under the cover of darkness

Original post by Flinders University, Australia

Australian bees are known for pollinating plants on beautiful sunny days, but a new study has identified two species that have adapted their vision for night-time conditions for the first time.

The study by a team of ecology researchers has observed night time foraging behaviour by a nomiine (Reepenia bituberculata) and masked (Meroglossa gemmata) bee species, with both developing enlarged compound and simple eyes which allow more light to be gathered when compared to their daytime kin.

Published in the Journal of Hymenoptera Research, the researchers explain that this improved low-light ability could potentially also exist in other Australian species secretly active at night, with their image processing ability best observed through high-resolution close-up images.

Lead author PhD Candidate James Dorey, in the College of Science & Engineering at Flinders University, says the two Australian bee species active at night and during twilight hours are mostly found in Australia’s tropical north, but there could potentially more in arid, subtropical and maybe even temperate conditions across the continent.

“We have confirmed the existence of at least two crepuscular bee species in Australia and there are likely to be many more that can forage both during the day and into the early morning or evening under low light conditions. It’s true that bees aren’t generally known to be very capable when it comes to using their eyes at night, but it turns out that low-light foraging is more common than currently thought,”
says Mr Dorey.

“Before this study, the only way to show that a bee had adapted to low-light was by using difficult-to-obtain behavioural observations, but we have found that you should be able to figure this out by using high-quality images of a specific bee.”

Mr Dorey says bees that forage during dim-light conditions aren’t studied enough with no previously reliable published records for any Australian species.

“Our study provides a framework to help identify low-light-adapted bees and the data that is needed to determine the behavioural traits of other species. This is important as we need to increase efforts to collect bee species outside of normal hours and publish new observations to better understand the role that they play in maintaining ecosystems.”

The researchers outline why more needs to be understood about the behaviour of bee species to help protect them from the potential impacts of climate change.

“Global weather patterns are changing and temperatures in many parts of Australia are rising along with the risk of prolonged droughts and fires. So, we have to improve our understanding about insects pollinating at night or in milder parts of the day to avoid potential extinction risks or to mitigate loss of pollination services.”

“This also means we have to highlight the species that operate in a narrow window of time and could be sensitive to climatic changes, so conservation becomes an important concern. Because quite frankly, we have ignored these species up until now.”

Publication:

Dorey JB, Fagan-Jeffries EP, Stevens MI, Schwarz MP (2020) Morphometric comparisons and novel observations of diurnal and low-light-foraging bees. Journal of Hymenoptera Research 79: 117–144. https://doi.org/10.3897/jhr.79.57308

A new species of Darwin wasp from Mexico named in observance of the 2020 quarantine period

“We thought that it was a good idea to remember this extraordinary year through the name of one remarkable species of Darwin wasp found in seven Mexican States (including Tamaulipas, where the UAT campus is located) and also Guatemala,” comment the researchers who discovered the previously unknown species.

Scientists at the Autonomous University of Tamaulipas (UAT) in Mexico recently discovered five new species of parasitoid wasps in Mexico, but the name of one of them sounds a bit weird: covida. Why this name?

In fact, the reason is quite simple. The thing is that the team of Andrey Khalaim (also a researcher at the Zoological Institute of Russian Academy of Sciences in Saint Petersburg, Russia) and Enrique Ruíz Cancino discovered the new to science species during the 2020 global quarantine period, imposed due to the COVID-19 pandemic. Their findings are described in a newly published research article, in the peer-reviewed, open-access scientific journal ZooKeys.

“We thought that it was a good idea to remember this extraordinary year through the name of one remarkable species of Darwin wasp found in seven Mexican States (including Tamaulipas, where the UAT campus is located) and also Guatemala,”
explain the scientists.

The new species, which goes by the official scientific name Stethantyx covida, belongs to the Darwin wasp family Ichneumonidae, one of the most species-rich insect families, which comprises more than 25,000 species worldwide.

“Darwin wasps are abundant and well-known almost everywhere in the world because of their beauty, gracility, and because they are used in biological control of insect pests in orchards and forests. Many Darwin wasp species attack the larvae or pupae of butterflies and moths. Yet, some species are particularly interesting, as their larvae feed on spider eggs and others, even more bizarre, develop on living spiders!”
further explain the authors of the new study.

Stethantyx covida is a small wasp that measures merely 3.5 mm in length. It is predominantly dark in colour, whereas parts of its body and legs are yellow or brown. It is highly polished and shining, and the ovipositor of the female is very long and slender.Along with Stethantyx covida, the authors also described four other Mexican species of Darwin wasps from three different genera (Stethantyx, Meggoleus, Phradis), all belonging to the subfamily Tersilochinae. Some tersilochines are common on flowers in springtime. While the majority of them are parasitoids of larvae of various beetles, some Mexican species attack sawflies, inhabiting the forests.

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Original source:

Khalaim AI, Ruíz-Cancino E (2020) Contribution to the taxonomy of Mexican Tersilochinae (Hymenoptera, Ichneumonidae), with descriptions of five new species. ZooKeys 974: 1-21. https://doi.org/10.3897/zookeys.974.54536