The evolution of parental care in insects
Repository URI
Repository DOI
Type
Change log
Authors
Abstract
This thesis concentrates on evolutionary costs and benefits of insect parental care. I use phylogenetic methods to test large-scale hypotheses, and field studies to test proximate hypotheses. Initially I look at the evolution of variation in the sex performing care, reconstructing transitions across insect evolutionary history. Consistent with theory, early insects had no care, and their descendants evolved either male care, or female care followed sometimes by biparental care. Secondly, I investigate parental care trade-offs. I find that in insects, care is associated positively with offspring survival but negatively with fecundity, suggesting a general trade-off between current and future reproduction. In the second part of the thesis, I use the assassin bug genus Rhinocoris to investigate proximate costs and benefits influencing male care, the rarest form of care. High density is predicted to favour male care; I investigate why male-caring Rhinocoris live at high density on the plant Stylosanthes. Plant preference is rare in predators and I show that the plant protects eggs from predators as well as harbouring favourable prey, factors not usually linked to parental care. Lastly I investigate an unstudied sexual conflict in male-carers. If females prefer caring males, males should be selected to display their eggs conspicuously. Conspicuousness may carry costs to eggs, so females should prefer inconspicuous locations. In the field this conflict exists for one Rhinocoris species but is absent in a sister species, showing that parental care can have complex effects. My results show that while broad patterns of costs and benefits largely follow theory, finer patterns depend on subtle ecological factors.
Description
This thesis is not available on this repository until the author agrees to make it public. If you are the author of this thesis and would like to make your work openly available, please contact us: thesis@repository.cam.ac.uk.
Cambridge University Library can make a copy of this work available only for the purposes of private study and non-commercial research. Copies should not be shared or saved in any shared facilities. Copyright over the content of these works is with their authors. Theses from the Library collection are considered unpublished works and according to UK legislation quoting from them is not allowed without permission from their author.
If you can commit to these terms, please complete the request form which you can find through this link: https://imagingservices.lib.cam.ac.uk/
Please note that print copies of theses may be available for consultation in the Cambridge University Library's Manuscript reading room. Admission details are at http://www.lib.cam.ac.uk/collections/departments/manuscripts-university-archives