I have examined variation in the reproductive behaviour of the Panamanian bishop <i>Brachyrhaphis episcopi</i>, a tropical poeciliid fish. Firstly, I explored male mate choice, which is an understudied but rapidly growing area of research. I found that even in this promiscuous species, males were choosy about the females that they mated with. Males showed mating preferences for unfamiliar females and for larger females, preferences that could increase the number of offspring sired. Male mate choice showed some degree of plasticity both seasonally and on a much shorter time-scale, which may reflect fluctuations in the costs and benefits of being choosy. Secondly, I examined between and within population variation in reproductive behaviour to find out whether ecological factors driving variation in closely-related species could be more generally applied. Field observations revealed that, despite large inter-population variation in predation pressure, there was little inter-population variation in male reproductive activity or behavioural repertoire. Instead, male reproductive behaviour showed significant variation within populations, which may be linked to local operational sex ratio. Reproductive success in this thesis is likely to be linked to male-male competition rather than female choice. Thirdly, I examined variation in individual reproductive investment by males. I looked at both reproductive tactics and other traits associated with mating success, such as testes mass. I found relationships between male size and mating behaviour, but no size-based differences in relative testes investment.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:661922 |
| Date | January 2006 |
| Creators | Simcox, Helen R. |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/12939 |
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