Mr Amirhossein Tourani1, Dr Alihan Katlav1, Professor James Cook1, Professor Markus Riegler1

1Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, Australia

Biography:

I am a dedicated researcher specializing in insect biology and ecology. My doctoral research focuses on investigating the dynamics of maternally inherited endosymbionts, specifically Cardinium and Wolbachia, in populations of the haplodiploid Kelly’s citrus thrips, P. kellyanus. This project is groundbreaking as it explores how Wolbachia spreads in host populations by the means of reproductive manipulation and assesses the potential of the Wolbachia-facilitated incompatible insect technique (IIT) for biological pest control in an insect species of the haplodiploid arthropod group, which represents a significant portion of biodiversity, including numerous pest species.

Honors & Awards:

– Awarded an excellent grade for MSc thesis in 2017.

– Recognized for the best MSc thesis of the Faculty of Agriculture at Shahed University in 2017.

– Received the Prof. Jalal Afshar Award for MSc thesis at the 2nd Iranian International Congress of Entomology 2017.

– Recipient of the Western Sydney University Postgraduate Research Award in 2022.

Abstract:

Wolbachia and Cardinium are two common maternally inherited endosymbionts of arthropods. They can affect host reproduction which can increase endosymbiont prevalence within and across host populations. One major reproductive effect is cytoplasmic incompatibility (CI), which results in embryonic offspring mortality in uninfected females mated with infected males. Theory suggests that CI exerts selective pressure on hosts to evolve mating behaviours that avoid CI-associated costs. This may involve precopulatory behaviours including mating receptivity and preference, but this has rarely been investigated. Here, we studied Pezothrips kellyanus, an Australian-native significant pest of citrus naturally infected with CI-inducing Cardinium and Wolbachia. We tested whether females evolved abilities to recognize and avoid incompatible males to limit the cost of CI. For this, we conducted experiments examining female mating receptivity, as well as male and female mating preferences in different mating combinations of endosymbiont-free, Cardinium-only and Cardinium-Wolbachia infected individuals. Results showed that females are generally choosier than males, and, therefore, female mating behaviour also affects male mating options. Moreover, compared to coinfected females, Cardinium-only infected females were less receptive to incompatible males and showed significant preference for compatible males. Surprisingly, this reduced female receptivity and preference towards incompatible males was not observed in endosymbiont-free females. Our findings suggest that Cardinium enables females to avoid Wolbachia-infected males, thereby preventing incompatible matings. Consequently, this may hinder a CI-driven Wolbachia spread through host populations. Our study highlights the significance of mating receptivity and preference in the invasion dynamics of CI-inducing endosymbionts and their application in pest management programmes.