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

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