Mrs Darshika Madhujeewani Dissawa Dissawe Mudiyanselage1, Associate Professor Fleur Ponton1

1Macquarie University, Australia

Biography:

I am a higher-degree research student at Macquarie University working in "Ponton Lab", specializing in entomology with a focus on the impacts of environmental factors on insect reproduction. My master's degree focused on exploring the reproductive effects of antifungal agents on insects, using Drosophila melanogaster as a model organism.

In my current research, I utilized toxicological assays and biochemical techniques to investigate how antifungal treatments influence insect fertility and developmental processes. This work not only contributes to the field of environmental entomology but also offers insights that may influence pest management practices and ecological conservation efforts.

Abstract:

Chlorothalonil is a fungicide that is widely used in agriculture around the world. The extensive application of chlorothalonil raises concerns about its impacts on non-target species, such as invertebrates. The present study explored the effects of chlorothalonil chronic exposure on the larval development and the reproductive output of the vinegar fly, Drosophila melanogaster. Flies were exposed to ten increasing concentrations of chlorothalonil at their larval stage. The effects of chlorothalonil were measured on larval pupation, as a proxy of larval survival and development, female fecundity (i.e. body weight, number of ovarioles, and number of eggs), and male iron level. Results showed a reduction in larval survival and an increase in developmental time for exposed larvae. Females had a lower body weight, a reduced number of ovarioles, and laid fewer eggs even when exposed to the lowest concentration of chlorothalonil (5 mg/kg of substrate) compared to non-exposed individuals. Males showed a lower iron content, suggesting altered iron metabolism following chlorothalonil exposure. These results demonstrate that chronic exposure to chlorothalonil has direct effects on insect larval mortality and sub-lethal effects on insect reproduction. Measuring the toxicity of agrochemicals on non-target organisms is an essential challenge to implement conservation measures.