Ms Madalene Giannotta1, Dr Kevin Williams3, Prof Craig Moritz1, Dr Juanita Rodriguez2

1Australian National University: Research School of Biology, Canberra, Australia, 2CSIRO: Australian National Insect Collection, Canberra, Australia, 3California Department of Food & Agriculture, Sacramento, USA

Biography:

Madalene is a final year PhD student at the Australian National University and the Australian National Insect Collection supervised by Dr. Juanita Rodriguez. She is interested in Hymenopteran systems, particularly those exhibiting a parasitoid lifestyle, and is actively working on the Mutillidae, Ichneumonidae, and the Chalcidoidea. Today, she will share insights from her doctoral research on the Australasian velvet ants.

Abstract:

Velvet ants are a diverse, and often-times abundant, family of parasitoid wasps, characterised by extreme sexual dimorphism and various anti-predator adaptations. Female velvet ants are apterous and exhibit several defensive traits: a painful venomous sting; the largest sting-to-body ratio among hymenopterans; a thick exoskeleton; large cuticular spines; and aposematic signals (olfactory, auditory, and visual). These aposematic traits contribute to their participation in one of the largest known Müllerian mimicry complexes. Despite their diversity, abundance, ecological significance, mutillids are often underrepresented in collections and understudied, especially in Australia. Most Australian species belong to the likely polyphyletic genus, Ephutomorpha, with many species virtually unidentifiable, even at the genus level. Associating the sexes is unsurprisingly challenging, with only 4% of species known from both sexes. Given the challenging nature of mutillid taxonomy, a comprehensive molecular phylogeny is essential for understanding the true diversity and relationships within the Australasian fauna. Here, we use a large morphometric and UCE-phylogenomic dataset spanning all currently described Australian genera, to reconstruct the first molecular phylogeny of the Australasian Mutillidae and clarify species and generic boundaries. Further, by analysing colour-trait data from 5,000 female mutillid wasps, we identify four putative mimicry rings in Australia, characterised by strong colour-pattern similarities not due to shared ancestry. This study resolves long-standing taxonomic uncertainties, builds on evidence of velvet ants forming large Müllerian mimicry complexes, and offers a framework to assess evolutionary and ecological processes shaping present-day patterns of diversity on a continental scale.