PSYC 3280 Chapter Notes - Chapter 7: Operational Sex Ratio, Bowerbird, Nuptial Gift
4 Feb 2018
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Displays: stereotyped actions used to communicate with others. If males lived shorter but reproduced more, then the ornaments, displays and behaviours that reduced longevity could spread over time: females like the neater bowers with feathers. It is believed that good bower builders are healthier birds and are less likely to infect their mates with parasites or pathogens. Stephanie doucet and bob montgomerie- found that males who built better bowers have fewer ectoparasitic feather mites: there is some evidence that brainier bowerbirds experience greater reproductive success. Sexual differences theory: males produces small sperm and females produce large eggs. Robert trivers labelled it parental investment: operational sex ratio: the ratio of sexually active males to sexually receptive females. This hypothesis predicts that the differences between the behavioural phenotypes are environmentally caused, not based on hereditary differences: the scorpionfly will use whichever tactic gives him the highest chance of mating. Concluding that the requiremens for a three-distinct strategies explanation had been met.
