Sex, diet, health and lifespan in the fruit fly, Drosophila melanogaster

Duxbury, Elizabeth (2017) Sex, diet, health and lifespan in the fruit fly, Drosophila melanogaster. Doctoral thesis, University of East Anglia.

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Abstract

Nutrition is a vital determinant of lifespan, reproduction, health and ageing. Much has been done
to investigate the lifespan consequences of short-term (proximate) nutritional manipulation, but
much less is known about long-term (evolutionary) nutritional manipulation and nutritional
mismatches. In this thesis I addressed this important omission, using the fruit fly, Drosophila
melanogaster, model system. I empirically tested two evolutionary theories: the Thrifty
Phenotype and Thrifty Genotype hypotheses, which predict the general life history consequences
of nutritional mismatches over the lifetime or over evolutionary time, respectively. I also tested
how the latter interacted with long-term nutritional selection regimes. Contrary to predictions, I
showed that the costs of nutritional mismatches between developmental and adult diets were
not universal, but instead dependent on the nature of the mismatch, sex and the components of
life history measured (Chapter 2). Similarly, the costs of mismatches between evolved and
proximate nutrition were dependent on evolved feeding regime, sex, life history component
measured and proximate diet (Chapter 3). I discovered that there was enhanced sexual
dimorphism for lifespan in nutritionally selected lines, which was associated with sex-specific life
history patterns and a partial resolution of sexual conflict (Chapter 4). Transcriptome-wide
analysis of these nutritionally selected lines revealed differential expression in genes with
functions related to lifespan, post-mating responses, regulation and epigenetic modification
(Chapter 5). Finally, I found that manipulation of another important component of altered
lifestyles, activity level, had no effect on lifespan or reproduction (Chapter 6). Overall, my results
make a novel contribution to the study of nutritional mismatches and long-term nutritional
selection. The results also highlight the importance of simultaneously studying both sexes and
several age-specific components of life history, in different proximate environments, to fully
elucidate the fitness consequences of nutritional manipulation.

Item Type: Thesis (Doctoral)
Faculty \ School: Faculty of Science > School of Biological Sciences
Depositing User: Katie Miller
Date Deposited: 03 May 2017 10:08
Last Modified: 03 May 2017 10:08
URI: https://ueaeprints.uea.ac.uk/id/eprint/63358
DOI:

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