Spotlighting Darwin wasps (Hymenoptera, Ichneumonidae) in Zambia: a new species and the urgent need for further exploration.

Abstract

The parasitoid Darwin wasps (Ichneumonidae) are one of the most species-rich families of insects, with a crucial role in ecosystem functioning while many species are known as potential biological control agents. However, the group is poorly studied, especially in the Afrotropical realm, where for several countries only a handful of species have been recorded. Zambia is one of the countries with the fewest records for Darwin wasps with only 26 species reported in the largest Ichneumonidae database, "Taxapad", from 2016 and subsequent publications. In this study, the species of Darwin wasps recorded from Zambia were reviewed and complemented with newly collected species in the Northern Province, to provide a first preliminary checklist of Darwin wasps in Zambia. Our findings increased the number of species known for Zambia to 44, which might still represent as little as 1.7% of the true diversity of the group. Despite the limited scale of the study, one new species of Afrotropical Cremastinae, Pristomerusroussei Meier, Viertler & Spasojevic, sp. nov., is described. The study thus highlights both the substantial potential for discovery of new taxa and significant gaps in our knowledge about the Darwin wasp diversity in Zambia. To tackle these shortcomings, comprehensive collecting efforts considering the various ecotypes found in Zambia are recommended, as well as studies of natural history collections, collaborative effort by taxonomic experts, and enhancing local capacities for taxonomic research by involving students and enlarging local natural history collections.