In the first chapter of this dissertation, I explore the role of shared evolutionary history in determining predation preferences of a suite of three generalist muricid whelks preying on oysters and mussels. Various theories such as the enemy release and novel weapons hypotheses predict how evolutionary novelty will affect predator-prey interactions, but it is not clear how applicable these theories are to interactions between generalist predators and familiar prey types. In addition to determining whether the one native and two invasive whelks preferred to consume evolutionarily familiar or novel oysters and mussels, I determined the optimality of each prey species via metrics such as food reward, ease of predation (shell thickness), and food:handling time ratios. By explicitly asking if predation hierarchies mirrored optimality, I was able to determine whether evolutionary constraints were preventing the whelks from consuming prey that were more optimal.
In the second chapter of the dissertation, I asked whether there had been post-invasive changes in predation preferences for one of the invasive whelks used in the first chapter, the Eastern oyster drill Urosalpinx cinerea. The results of this study, which indicate that even highly generalist invasive predators consuming a familiar prey type can experience post-invasion changes in naïveté and predation preference strength, serve as a reminder that a potential or new invader's interactions with and impact on species in the recipient community can be hard to predict.
The third chapter of this dissertation documents the loss of an invasive predator's naïveté towards new species prey in real time, and compares the two prey species' behavioral and morphological responses to both general and specific predation cues. I studied the predator-prey dynamics of the invasive European green crab Carcinus maenas and two species of snails, both of which are invasive on the Pacific coast of North America: the Eastern mud snail Ilyanassa obsoleta and the Asian hornsnail Batillaria attramentaria.The results of this research lead me to conclude that, as with the results of Chapter 2, even generalist predators are capable of losing naïveté to new prey and of changing prey preferences following relatively short exposure to new prey. In addition, this research indicates that between species that do not share an evolutionary history, CEs may be very quick to develop, while NCEs that are induced by predator cues may not be like NCEs between evolutionarily familiar species, and may augment the CEs. (Abstract shortened by UMI.)
|Advisor:||Grosholz, Edwin D.|
|Commitee:||Sanford, Eric D., Sih, Andrew|
|School:||University of California, Davis|
|School Location:||United States -- California|
|Source:||DAI-B 74/10(E), Dissertation Abstracts International|
|Keywords:||Invasive species, Invertebrates, Marine, Predation|
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