ABSTRACT
Sexual conflict arises when the reproductive interests of males and females diverge, often resulting in significant fitness costs. In species such as mosquitofish (Gambusia holbrooki), where mating is frequently coercive and male harassment is intense, social interactions and environmental conditions both play critical roles in shaping reproductive outcomes. To investigate how sexual conflict and environmental factors interact to influence reproductive strategies, physiological stress, and life-history traits in males and females I ran a set of laboratory experiments using mosquitofish. Across my four experimental chapters, I disentangled the costs associated with key sexual selected behaviours. First, I separated the effects of sexual harassment and multiple mating on female fitness, demonstrating that neither harassment nor multiple mating tend to impose detectable costs. Second, I examined the life-history trade-offs in males between direct competition for mates (fighting) and increased sperm production to show that there was no detectable trade-off. Third, I explored the role of environmental context on female stress, measured as their cortisol level.  I showed that reduced water turbidity elevates female physiological stress, while male harassment levels does not affect female physiological stress. This finding highlights the importance of abiotic conditions in modulating the impact of sexual conflict. Finally, I investigated how temperature and salinity influence male reproductive traits, including sperm quantity and quality. I demonstrated that environmental variation can significantly alter male reproductive performance. Together, my findings provide a comprehensive understanding of how sexual conflict operates within an ecological framework, emphasizing the combined influence of behavioural interactions and environmental stressors. My research contributes to broader insights into sexual selection, life-history evolution, and the potential impacts of environmental change on reproductive dynamics in natural populations.
 

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BIOGRAPHY
Fatema was born in a beautiful city in Bangladesh, she completed her Bachelor of Science in Fisheries from Chattogram Veterinary & Animal Sciences University (CVASU), where she was awarded the prestigious University Gold Medal and the Dean’s Award for her outstanding academic performance. Later she obtained her master’s degree in Fish Biology and Biotechnology from the same institution. Driven by a strong passion for teaching, Fatema began her academic career as a Lecturer in the Department of Fish Biology and Biotechnology at CVASU, serving from November 2017 to August 2022 (currently on study leave). From the outset of her career, she has worked extensively on fish, with a primary focus on reproductive biology and physiology, while also maintaining a strong interest in behavioural biology. Currently, she is pursuing her Ph.D. at ANU, focusing on sexual conflict in mosquitofish and investigating how environmental factors influence the intensity of this conflict. Looking ahead, she aims to further develop her expertise in behavioural biology and establish herself in this field upon returning to her home country.