Variation in male post-copulatory investment: ontogeny to progeny

Download files
Access & Terms of Use
open access
Copyright: Macartney, Erin
Altmetric
Abstract
Condition-dependence theory has been widely applied to exaggerated male signaling traits, and more recently to certain sperm and semen traits. However, such post-copulatory traits can be highly cryptic and multi-faceted, and the published literature shows considerable variation in trait expression due to male condition. This thesis aims to uncover sources of variation in post-copulatory trait expression, and to incorporate male investment in ejaculate and offspring quality into a condition-dependence life-history framework. Using meta-analyses and meta-regression in Chapter Two, I demonstrate that much of the variation in post-copulatory responses to nutrient limitation (used as a manipulation of condition) is accounted for by differences in the type of nutrients, the ontogenetic life-stage when nutrients are limited, and the type of trait. Trait responses are also taxon-specific. In Chapter Three, I empirically demonstrate that developmental nutrient limitation strongly reduces testes and accessory gland size, as well as sperm movement within the female reproductive tract, and that adult diet does not alter such responses in the neriid fly, Telostylinus angusticollis. In Chapters Four and Five, I consider condition-dependent effects on offspring quality. In Chapter Four, I argue that non-genetic paternal effects conferred through epigenetic factors may also be costly, condition-dependent traits. In Chapter Five, I use T. angusticollis to test if frequent mating results in a condition-dependent reduction in fecundity and offspring quality. Surprisingly, frequent mating did not result in reduced fecundity or offspring quality, but did result in a reduced mating rate. Finally, in Chapter Six, I demonstrate that male Drosophila melanogaster suffer sperm depletion across successive matings, but the rate of depletion is not dependent on diet or genotype. Instead, males vary in ability to mate multiply, and individuals that mate more also transfer more sperm. Thus, variation in male post-copulatory performance depends substantially on unknown factors that are unrelated to nutrition and genotype. Overall, this thesis demonstrates that sperm and semen traits are affected by many different factors, and that variation in such traits can be highly complicated. Understanding differences in post-copulatory trait expression will provide increased understanding into the evolution of mating systems and reproductive investment.
Persistent link to this record
Link to Publisher Version
Link to Open Access Version
Additional Link
Author(s)
Macartney, Erin
Supervisor(s)
Creator(s)
Editor(s)
Translator(s)
Curator(s)
Designer(s)
Arranger(s)
Composer(s)
Recordist(s)
Conference Proceedings Editor(s)
Other Contributor(s)
Corporate/Industry Contributor(s)
Publication Year
2019
Resource Type
Thesis
Degree Type
PhD Doctorate
UNSW Faculty
Files
download public version.pdf 8.74 MB Adobe Portable Document Format
Related dataset(s)