Tag: Costa Rica

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

Get to know them faster: Alternative time-efficient way to describe new moth species

Having collected thousands of moth and butterfly species from across Costa Rica, famous ecologist Daniel Janzen, University of Pennsylvania, and his team were yet to find out many of their names. When they sought help from Dr. Gunnar Brehm, the taxonomist realised he needed too much time to describe species in the framework of an extensive revision of the genus, especially as there are still only a few biologists skilled to do this.

In the end, he found a way to revise the Neotropical looper moth genus Hagnagorafast and efficiently through avoiding wordy descriptions, but focusing on diagnostic characters, illustrated external characters, genitalia structures and DNA barcoding instead. His study is available in the open-access journal ZooKeys.

Having been put together back in the 19th century, most of the species within the Neotropical moth genus Hagnagora had been described by 1913. In modern days, it seemed necessary for the taxon to be revised. As a result, Dr. Gunnar Brehm herein publishes a “concise revision” comprising twenty species. It includes two species that have been revived from synonymy, two subspecies reinstated to a species level, four species excluded from the genus and the description of three new to science. In honour of the people who had funded the research, the new species have been named after them.

Following the revision, the research concludes not only the DNA molecules divergence between the separate species, but some subtle differences such as size, form of the wing blotches or the shape of the male genitalia.

Curious characteristic behaviour traits have also been noted within the genus. The representatives of the discussed genus fold their wings vertically while resting just like most butterflies and unlike the majority of related geometrid moths. Similarly, three of the revised species were noticed to be active during the day when they would often perch on moist substances like rotting plants, mud or dung, from whose fluids they would find vital nutrients.

The author stresses on the fact that taxonomists can hardly keep up with the pace inventories are being compiled, nor with the accelerating destruction of tropical rainforests. “Taxonomists therefore need to accelerate their workflows and try to make their papers useful not only to other taxonomists but for ecologists who need their support”, Dr. Gunnar Brehm says.

“What used to be one species ten years ago, known as Hagnagora anicata, is now regarded as a complex of six species, and more might be discovered in South American rain forests”, Brehm says. “Integrating information of molecules and morphology, as concisely as possible, appears to be one promising way to cope with the problem of slow taxonomy”, he explains in conclusion.

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Original source:

Brehm G (2015) Three new species of Hagnagora Druce, 1885 (Lepidoptera, Geometridae, Larentiinae) from Ecuador and Costa Rica and a concise revision of the genus. ZooKeys 537: 131-156. doi: 10.3897/zookeys.537.6090