Effects of microbe deposition, pheromone deposition, and the social environment on dietary choice in mated female Drosophila melanogaster.

Millar, Katherine (2024) Effects of microbe deposition, pheromone deposition, and the social environment on dietary choice in mated female Drosophila melanogaster. Masters thesis, University of East Anglia.

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Abstract

Dietary variation is key to health and organismal fitness. In the model organism used throughout this thesis, the fruitfly Drosophila melanogaster, the strength and nature of dietary preferences can be differentially influenced by sex and mating status. Individuals of both sexes will usually feed and develop as larvae through to adulthood within shared dietary environments. This will expose individuals to gut microbes, pheromones and digestive byproducts from others, which may have significant impacts on health and development. The potential costs and benefits of feeding on or developing in shared (‘conditioned’) environments are not known. Therefore, it is of great interest to investigate whether flies prefer conditioned diets when given this choice and the consequences for fitness of any such decisions. In this thesis, I used choice assays to test the preference of mated females to feed and lay eggs on ‘conditioned’ versus ‘non-conditioned’ diets. I then tested the developmental consequences of being reared on either type of diet. I first investigated the dietary preferences of mated females for high protein and high carbohydrate diets that were conditioned by males, virgin females or OvoD1 (eggless) females. I tested these preferences in both “absolute” (two-choice) and “relative” (four-choice) assay environments. The results showed that there were clear preferences for feeding and laying on conditioned diets, especially on the high protein diet for feeding, and the high carbohydrate diet for oviposition. I then investigated how being reared on a conditioned or non-conditioned diet impacts pre-adult survival and body weight at emergence. I found that conditioned diets slowed developmental speed, though there were no immediate effects on pre-adult survival or body weight at emergence. Therefore, the fitness benefits of preferences for conditioned diets have not yet been identified. Finally, I discuss the potential next steps for investigating the mechanisms behind diet conditioning, including demonstrating dose-response effects of conditioning. I also discuss the broader context and importance of my results for understanding life-history traits, and suggest future experiments to investigate the wider significance of diet conditioning.

Item Type:	Thesis (Masters)
Faculty \ School:	Faculty of Science > School of Biological Sciences
Depositing User:	Chris White
Date Deposited:	20 Mar 2025 14:53
Last Modified:	20 Mar 2025 14:53
URI:	https://ueaeprints.uea.ac.uk/id/eprint/98832
DOI:

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