Ms Madalene Giannotta1, Dr Ina Smith3, Dr Michelle Michie3, Dr Kim Blasdell4, Dr James Nicholls2, Dr Juanita Rodriguez2, Dr Allen Heath5, Dr Alexander Gofton3

1Australian National University: Research School of Biology, Canberra, Australia, 2CSIRO: Australian National Insect Collection, Canberra, Australia, 3CSIRO: Health and Biosecurity Australia, Canberra, Australia, 4CSIRO Health and Biosecurity Australia, Australian Centre for Disease Preparedness, Geelong, Australia, 5National Centre for Biosecurity and Infectious Disease, Wallaceville, New Zealand

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:

Ticks are medically and agriculturally important pests that represent a substantial threat to the livestock industry and a serious health concern for humans and companion animals. Ixodiphagus wasps are known endoparasitoids of ixodid and argasid ticks, with potential utility as natural biocontrol agents. Two species, I. brunneus and I. mysorensis, are previously recorded from Australia, however, the Ixodiphagus fauna lacks formal revisionary work, and the validity and host-ranges of these species remain uncertain. Here, we investigate the diversity of Ixodiphagus in Australasia and provide a molecular resource for future work on these understudied endoparasitoids. We screened 178 tick-pools containing questing nymph and adult ticks, Ixodes holocyclus (eastern paralysis tick) and Haemaphysalis bancrofti (wallaby tick), from two sites in eastern NSW, for the presence of hymenopteran parasitoids by 28S rRNA PCR. High-throughput genomic DNA sequences were also obtained from Australian archival Ixodiphagus specimens, and an I. taiaroaensis specimen from NZ. Archival samples yielded complete mitoGenomes from ten Ixodiphagus specimens from Australia as well as from I. taiaroaensis from NZ, including approximately 70% of the genome of the Wolbachia endosymbiont. Phylogenetic analysis of Australasian Ixodiphagus spp. based on 28S rRNA and complete mitoGenome sequences determined that Australasian Ixodiphagus are distinct from I. hookeri (the only other Ixodiphagus species for which genetic data exists), and that at least two distinct species are present in Australia; I. brunneus identified in Ixodes holocyclus and Haemaphysalis bancrofti ticks, and an uncharacterised species found in Rhipicephalus linnaei ticks from northern Queensland. Furthermore, there was substantial genetic 28S rRNA diversity among I. brunneus samples, which may represent normal genetic variability or a third cryptic species. The molecular data generated here represents the first-ever for the Australasian Ixodiphagus, doubles that of the world fauna, and provides the first-ever complete mitochondrial genomes for these important tick parasitoids.