Eusterinx Darwin wasps recorded from Africa for the first time

Simon van Noort

(Research and Exhibitions Department, Iziko Museums of South Africa)

Darwin wasps in the genus Eusterinx (Orthocentrinae, Ichneumonidae) were previously unknown in Africa. The first species, Eusterinx africana, was described and named in 2024 based on specimens from South Africa (Humala, 2024), and a further eight species were subsequently described in 2025 and 2026 (Humala & van Noort, 2025; Varga, 2026):

https://www.waspweb.org/Ichneumonoidea/Ichneumonidae/Orthocentrinae/Eusterinx/index.htm

These wasps are now known from five countries in central, eastern and southern Africa. Their discovery is the result of long-term inventory surveys conducted by Bob Copeland (ICIPE) in east Africa and Simon van Noort (Iziko) in southern, central and east Africa. Biodiversity inventory surveys are critical to provide baseline data for documentation of insect species richness in Africa (including the description of thousands of new species) allowing for assessment of the rate of insect decline due to ongoing habitat destruction. Most wasp species in Africa remain undiscovered (we only know about 5-20% of the possible half a million wasp species present on the continent) and many will go extinct before we can document them. Elucidating biodiversity data and species description is important for conservation through informing effective long-term management of ecosystems.

Through further mobilisation of the samples emanating from these already conducted inventory surveys, which produce millions of specimens (van Noort, 2025), but that are only just scratching the surface of the super abundant insect biodiversity present in our natural habitats, we will continue with the discovery of new species and records of genera previously unknown in Africa. The continent is extremely poorly surveyed for insect species, and every collecting trip produces hundreds to thousands of new species to science.

Currently we are undertaking a genetic analysis of over 3 000 Iziko specimens of the Darwin wasp subfamily Orthocentrinae, in collaboration with Bernardo Santos and Joan Kolasa from the Center for Integrative Biodiversity Discovery at the Museum für Naturkunde in Berlin. This research is expected to identify numerous additional new species of Eusterinx and related genera in this group of Darwin wasps: https://www.waspweb.org/Ichneumonoidea/Ichneumonidae/Orthocentrinae/index.htm.

Discovery and description of wasp species is fundamental to our well-being as they provide critical ecosystem services from pollination to predation, contributing towards maintenance of our exceptional plant diversity, to control of insect populations through parasitism and predation, and hence to the overall health and sustainability of our habitats.

Biology of the African Eusterinx species is unknown, requiring further ecological investigation, but a few Eusterinx species from other parts of the world are known to be parasitoids of flies – the Fungus Gnats in the family Keroplatidae. This family of flies is well represented in Africa with high diversity and are also likely to be the hosts attacked by the Eusterinx species occurring in the region.

Scientific papers detailing the discovery of these Darwin wasp species in Africa:

Humala AE 2024. First record of the genus Eusterinx Förster, 1869 (Hymenoptera: Ichneumonidae: Orthocentrinae) from the Afrotropical region, with description of a new species from South Africa. Zootaxa 5537(2): 281–287. https://doi.org/10.11646/zootaxa.5537.2.8

Humala, AE, van Noort S. 2025. New records of the genus Eusterinx Förster (Hymenoptera: Ichneumonidae: Orthocentrinae) from the Afrotropical Region, with description of four new species from Central African Republic, South Africa and Uganda. Journal of Hymenoptera Research 98: 817-839. https://doi.org/10.3897/jhr.98.157523

van Noort S. 2025. The Iziko South African Museum entomology collection: a goldmine of biodiversity data with mobilisation challenges for more than 50 million specimens. Biological Journal of the Linnean Society 145: blaf062 https://doi.org/10.1093/biolinnean/blaf062

Varga, O. 2026. Four new species of the genus Eusterinx Förster, 1869 (Hymenoptera, Ichneumonidae, Orthocentrinae) from Burundi and Kenya. Zootaxa 5760 (1): 124–138. https://doi.org/10.11646/zootaxa.5760.1.6