Hyperparasitic wasp discovered in UAE

The tiny insects adopt a risky reproduction strategy that has puzzled scientists

A new species of a type of tiny wasp with a striking appearance and an unusual life cycle, in which it parasitises other parasites, has been found in the UAE.

Researchers in Canada identified four new Perilampus species from specimens collected as part of a project to catalogue insects in the Emirates.

Stunning images of the creatures were published in the Zootaxa scientific journal after the insects were analysed by Dr Christopher Darling and his student Jeong Yoo, both of the Royal Ontario Museum and University of Toronto.

“I tend to think of them as Russian dolls. There’s the host. Inside that is the parasite. Inside that is the hyperparasite
Dr Christopher Darling

The new species are known only from dead museum specimens, so the exact details of their life cycle are not known.

But some Perilampus species are “hyperparasites”, or parasites of other parasites, and Dr Darling said it was highly likely that some of the new UAE species were hyperparasites too.

“I tend to think of them as Russian dolls. There’s the host. Inside that is the parasite. Inside that is the hyperparasite," he said.

Perilampus species have unusual life cycles, even by the standards of hyperparasites. The female adult wasp selects a plant on which to lay her eggs, which hatch into larvae, which then burrow into caterpillars found on those plants.

If the caterpillars are subsequently parasitised by the species that Perilampus species live off, the Perilampus larvae will burrow into them and later emerge as adult wasps.

But if the caterpillars are not attacked by this other type of insect, the Perilampus larvae will be unable to complete their life cycle.

“They’re getting into this caterpillar hoping it gets parasitised,” he said.

“If it doesn’t, the caterpillar completes its development into the moth or butterfly, and the Perilampus that is inside just dies.”

A risky strategy

Dr Darling said it was “a bit of a conundrum” as to why the wasp adopts “a risky strategy” when reproducing.

As adult wasps, the newly identified Perilampus are only a few millimetres long, making them smaller than related species elsewhere.

This “dwarfism” may be an adaptation to the desert climate of the Arabian Peninsula.

Another notable finding is that some of the species are similar to others in parts of the world with more rainfall and lush vegetation.

One species, P. awbalus, which has striking green and blue metallic colouration, has affinities to similar wasps in Madagascar and South Africa.

P. awbalus may, therefore, have evolved from wasps that lived on the Arabian Peninsula when it had a much wetter climate than today.

“As the climate became more arid, evolution may have produced new species that were able to survive in these dry habitats,” said Dr Darling, who has spent his career researching wasps in the Perilampidae family, which contains the Perilampus species.

The four UAE species, and another Perilampidae species newly identified in Yemen, are the first members of their family to be identified from the Arabian Peninsula.

The specimens were provided by Antonius van Harten, a Dutch entomologist who has co-ordinated a long-running project to catalogue the UAE’s arthropods, the animal group that includes insects and spiders.

Supported by the Environment Agency Abu Dhabi, this project has documented more than 3,700 species, of which 569 are new to science.

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Updated: August 22nd 2021, 3:00 AM