Taxonomy, distribution and host relationships of aphidiine wasps (Hymenoptera: Aphidiidae) parasitizing aphids (Hemiptera: Aphididae) in Australia grain production landscapes

Abstract

Aphid parasitoids (Hymenoptera; Aphidiidae) were surveyed within grain production landscapes in Victoria, Australia between 2017 and 2018, as well as more sporadically nationwide between 2016 and 2019. In addition, aphidiine records were collated from insect depositories around Australia and online databases. The 5551 specimens recorded constituted a total of 23 species and seven genera. Diaeretiella rapae (MIntosh) was the most common species, representing more than 70% of all aphidiines recorded. This species also showed a greater northerly geographic range than other aphidiines. During sampling between 2017 and 2019, aphidiines were reared from mummies to ascertain host-parasitoid relationships. Diaeretiella rapae was again the most commonly reared parasitoid, although aphidiine preference varied with aphid host and between states and territories. An illustrated dichotomous key to Australian aphidiines in grain production landscapes is provided for the 11 species sampled in our field surveys. This is the first comprehensive review of aphidiines sampled within Australia in over two decades. Knowledge about the diversity and distribution of these parasitoids is important for understanding their impact on current and future invasions of aphid species. In addition, understanding the interactions between grain aphids and their associated parasitoids will further support the inclusion of parasitoid wasps into integrated pest management (IPM) strategies.