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Title: Why are there imperfect Batesian mimics?
Author: Dow, Rohanna
Awarding Body: University of Nottingham
Current Institution: University of Nottingham
Date of Award: 2012
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Batesian mimicry was historically considered to be a perfect illustration of Darwin's theory of adaptation via natural selection. However, recent research has focussed on the seemingly paradoxical existence of so-called "imperfect" Batesian mimicry. The aim of this thesis was to explore in detail some of the main hypotheses attempting to explain the conundrum of mimetic imperfection. Firstly, by studying crab spiders foraging on mimetic and non-mimetic prey, I investigated the extent to which human perceptions of perfection may differ from those of a typical invertebrate predator. I found evidence to suggest that the spiders have the potential to select for the visual signals of their prey. It is possible that perceptual differences between humans and natural predators of mimics, could at least partly explain the persistence of seemingly inaccurate mimics. Secondly, using humans foraging for computer-generated prey, I examined the survival and evolution of mimetic phenotypes under different ecological scenarios. My results suggest that an increased availability of alternative prey could slow down the rate of evolution towards mimetic perfection. As predicted by Signal Detection Theory, a particularly unprofitable model protected a wider range of mimetic phenotypes. However, contrary to predictions, increasing the unpalatability of a model species increased selection for more accurate mimetic signals. Moreover my results indicate that imperfect "genera list" Batesian mimicry could be favoured in the presence of multiple models.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available