Functional significance of ecological factors during larval development

Ecological conditions during early development modulate survival and reproduction in adulthood, and can therefore have long - lasting fitness implications. Despite this, little is known about how ecological factors interact to shape the developmental environment and expression of life - history traits in adulthood. In this thesis, I investigated how two key ecological factors, population density and larval diet shape the development and life - history traits of the tephritid fruit fly Bactrocera tryoni. I generated five larval densities in three larval diets with different yeast - to - sugar ratios to test how these factors interact to shape the expression of life - history traits. I found that there was a significant interaction between larval density and larval diet on pupal weight, adult weight, emergence and body lipid reserves. Low larval density and protein - rich diet led to an increase in body weight, percentage of emergence and fecundity. Interestingly, an increase in larval density led to a decrease in the percentage of lipid reserves when flies were reared in the protein - rich and standard diets, whereas it induced an increase in lipid storage in the sugar - rich diet. High larval density and protein - rich diet shortened developmental time. There was no significant effect of larval density, diet, or their interaction on the sex ratio.