Parents modulate the phenotypes of their offspring, beyond the effects of the genes they pass on. These parental effects can have impacts on the fitnesses of those offspring, as well as the fitness of the parents themselves. Parental investment in offspring is expected to be under antagonistic selection through its beneficial effects to offspring, and its detrimental effects on the parent's own fitness. Evolutionary conflict over parental care is therefore expected to occur, and may cause evolutionary stasis. Furthermore, selection is also expected to act on offspring traits, in order to maximise offspring fitness within a given parental environment, generating predictions of parent-offspring coadaptation. I tested the predictions of conflict and coadaptation in parent-offspring interactions, using a population of blue tits (Cyanistes caeruleus), a species in which adults provide biparental care to their offspring. I found evolutionary conflict over offspring body mass, which may explain stasis in this trait. I also used a cross-fostering design to test for coadaptation between parents and offspring, and siblings. I did not find evidence for parent-offspring coadaptation, nor did I find that siblings were important through either direct interactions, or in mediating parent-offspring interactions, suggesting that there is little family coadaptation in this species. In addition, I investigated whether a maternal effect on hatching time was a passive consequence of environmental changes, or was an anticipatory maternal effect actively placed in eggs to manipulate hatching time. The results from this analysis suggest the latter to be the case, and mothers appear to actively manipulate offspring hatching time to reduce the extent of hatching asynchrony, which may reduce fitness costs to the offspring. By measuring the effects of interactions between individuals on phenotypes and fitness measures, I was able to show how parental effects on offspring can affect evolutionary dynamics. Such evidence of evolutionary conflicts has not previously been found, due to methodological issues with the ways in which selection has been measured. Thus, I highlight how gaps in knowledge about the evolutionary consequences of parental effects can be addressed using appropriate statistical tools and measures of fitness.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:730210 |
| Date | January 2016 |
| Creators | Thomson, Caroline |
| Contributors | Hadfield, Jarrod ; Sheldon, Ben |
| Publisher | University of Oxford |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | https://ora.ox.ac.uk/objects/uuid:baf94d58-4259-489a-a91a-8885e3d6613e |
Page generated in 0.0018 seconds