Rare parasitoid wasp discovered in South Africa

17/03/2022

Simon van Noort (Curator of Entomology, Research and Exhibitions Department)

Head of a Spathioplites phreneticus. Photograph © Simon van Noort (Iziko Museums of South Africa). Note the scale bar, which represents a fifth of a millimetre, meaning the head is less than a millimetre wide.

The discovery of the braconid parasitoid wasp Spathioplites phreneticus (Doryctinae) in South Africa is a result of the exploration of the huge diversity of unknown insect species by Iziko entomologists. This rare parasitoid wasp species (described and named in 1962 by Max Fischer based at the Natural History Museum in Vienna) was previously only known from a few specimens collected in Chad in 1959.

Spathioplites phreneticus belongs to the diverse braconid parasitoid wasp subfamily Doryctinae. Photographs © Simon van Noort (Iziko Museums of South Africa).

Two specimens of this species were collected by Iziko entomologist Simon van Noort during an insect inventory survey undertaken in Tswalu Kalahari Game Reserve in the Northern Cape Province in South Africa, extending the distribution range of this species southwards by 4900 km. An additional historical specimen collected in Senegal was discovered in the collections of the Natural History Museum in Paris, extending the species’ range westwards by 4000 km. 

Sampling locality of Spathioplites phreneticus in Tswalu Kalahari Game Reserve.

These widespread locality records typify how little we know about wasp species and their distribution in Africa. This lack of baseline biodiversity information is simply a result of insufficient surveys of our insect diversity, constrained by a lack of resources and available scientific expertise. The need for these surveys is becoming increasingly critical because this baseline data informs best practice in terms of conserving our natural heritage and ecosystems, the health of which is necessary for our continued quality of life.

This parasitoid wasp attacks wood-boring beetle larvae (Coleoptera, Bostrichidae), which develop inside the branches of the Umbrella thorn acacia (Vachellia tortilis), and via this control mechanism the wasp ensures the continued health of these acacia trees and hence the health of the broader ecosystems that the trees form part of. Documenting parasitoid wasp species and figuring out the role they play in our environment is an essential task, as these species control other insect populations through their parasitoid lifestyle. Without parasitoid wasps we would be inundated with plague outbreaks of insects.

Spathioplites phreneticus is only known from three localities (depicted by red circles) one each in Chad, Senegal and South Africa.

This discovery was published in: 
van Noort S, Belokobylskij SA, Touret-Alby A. 2021. Rediscovery of the endemic Afrotropical genus Spathioplites (Hymenoptera, Braconidae, Doryctinae) with major range extension records for Spathioplites phreneticus. African Invertebrates 62(2): 497–520.
https://doi.org/10.3897/AfrInvertebr.62.74103

Simon van Noort is Curator of Entomology having conducted research on wasp systematics and evolution at Iziko since 1992.
https://www.iziko.org.za/researcher/simon-van-noort
http://www.figweb.org/Research/Laboratories/van_Noort/index.htm 
https://www.researchgate.net/profile/Simon_Noort

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