(2023/08/10)

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16 strange new parasitoid wasp species discovered in Vietnam
A field survey in Vietnam searching for Loboscelidia, a rare group of parasitoid wasps, has
increased the total known number of species worldwide by 30% and uncovered their uniqueegg-burying behavior.
Researchers at Kyushu University and Vietnam’s National Museum of Nature have discovered
16 new species of Loboscelidia, a strange-looking and elusive group of parasitoid wasps. The
scientists also reported for the first time the unique parasitic behavior of a captive female ofone species, Loboscelidia squamosa, who was observed digging a hole in the soil to hide herhost’s egg.
The findings were published in the European Journal of Taxonomy.
While we are more familiar with hunting wasps like yellowjackets, with their dramatic blackand yellow stripes and painful stings, parasitoid wasps make up the vast majority of waspspecies. They are often tiny (Loboscelidia wasps are between 2-5 mm in body length, smaller
than a pencil-top eraser) and while unnoticed by humans, they play a crucial role inregulating the ecosystem.
"Parasitoid wasps act as a parasite of other insects. They lay their eggs in or on the bodies oreggs of their host, ultimately killing them," says Assistant Professor Toshiharu Mita of Kyushu
University’s Faculty of Agriculture, who led the research.
Despite their ecological importance, very little is known about many groups of parasitoid
wasps, including Loboscelidia. Prior research into the group has suggested that theyparasitize the eggs of stick insects, also known as walking sticks.
"Loboscelidia was first discovered around 150 years ago, but we still lack important
knowledge about their biology. This study was the first time we were able to observe theirparasitic behavior," says first author, Dr. Yu Hisasue, formerly a PhD student supervised byMita.
Mita and Hisasue, along with their colleague, Dr. Thai-Hong Pham of the National Museum ofNature, Vietnam, conducted field surveys at six sites across Vietnam, setting traps and usingnets to capture the tiny parasitoid wasps.
On one occasion, they trapped a living female from one of the newly described species,
Loboscelidia squamosa. They released her into a plastic container containing soil and placed astick insect egg inside. The female wasp punctured the egg, laid her own egg inside and thensearched for a location to bury the parasitized egg. She used her head to dig a hole, placed
the host egg inside and plugged the entrance with soil.

This parasitic behavior is very developed, and similar to the nest building behavior seen insolitary hunting wasps. The researchers therefore believe that further research could help
shed light on how these behaviors evolved in other wasps. It could also help explain theunique specialized head structure of Loboscelidia wasps, which could be useful for digging
holes in the soil.
By the end of the field survey, the scientists had collected 70 individuals from the Loboscelidia
group, taking high-resolution close-up photos of each wasp. One unusual feature of thewasps was the presence of hairs at the back of their head and on their body, with thearrangement and density of body hairs differing between each species.
In total, the scientists identified 16 new species, bringing the known number of species
worldwide up to 67.
"The Loboscelidia wasps were thought to be rare group with a small number of species, butwith one stroke, we have increased the number of species by 30%," says Mita.
Importantly, each species was typically found in a very limited area, usually only at one
collection site. This makes it likely that the group has many more species that still could bediscovered with further field surveys. However, it also highlights the vulnerability of eachspecies.
"As each species is only found in a small area, any disruption to their habitat could result inthe loss of that species forever," concludes Hisasue.
###For more information about this research, see "Taxonomic revision of the genus
Loboscelidia Westwood, 1874 (Hymenoptera: Chrysididae: Loboscelidiinae) from Vietnam" Yu
HISASUE, Thai-Hong PHAM, Toshiharu MITA in European Journal ofTaxonomy, https://doi.org/10.5852/ejt.2023.877.2203
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Fig. 1. 16 new species have been added to the group,
Loboscelidia, based on their unique physicalcharacteristics. Scale bar = 0.5 mm
Credit: Yu Hisasue et al. (2023) European Journal of
Taxonomy

Fig. 2. A series of photos captures the moment acaptive female wasp from the species Loboscelidia
squamosa lays her egg inside a stick insect egg
before carrying and burying it in the soil. Thismarks the first time that this parasitic behavior has
been observed.
Credit: Yu Hisasue, Kyushu UniversityFig. 3. First author, Yu Hisasue, looks in the leaf litter fortiny Loboscelidia wasps.
Credit: Toshiharu Mita, Kyushu University[Contact]
Toshiharu Mita, Professor
Faculty of Agriculture, Department of Bioresource Sciences
Tel: +81-92-642-2839
E-mail: t3mita@agr.kyushu-u.ac.jp