The role of scent and ectoparasites in the ecology of the crested auklet (aethia cristatella)

Munro, Hannah Jarvis (2011) The role of scent and ectoparasites in the ecology of the crested auklet (aethia cristatella). Masters thesis, Memorial University of Newfoundland.

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Abstract

Ectoparasites are ubiquitous, and can have negative effects on their hosts. The prevalence and intensity of ectoparasites are important in determining their effects. Prevalence can vary greatly, from near absence to all host individuals in a population being parasitized. Intensity can also vary greatly. Negative impacts of parasitizes can create the pressure required for a natural defence mechanism to evolve in hosts. Crested Auklets (Aethia cristella, Alcidae; Aethiini) are colonial seabirds that produce a unique tangerine-like scent. There are two hypotheses proposed for this scent's function: 1) as a pheromone; and 2) to reduce ectoparasite levels by repelling ticks and lice. My study is broken into three sections: 1) measuring the prevalence and intensity of ticks on Aethia auklets and determining the relationship of body condition and ornamentation to tick parasitism; 2) measuring the prevalence and intensity of lice on Least (Aethia pusilla) and Crested Auklets and the determining relationship of body condition and ornament expression to lice parasitism; and 3) the relationship of Crested Auklet scent to ectoparasite intensity and tick deterrence. I determined that prevalence and intensity of ticks and lice had no relationship with body condition or ornament expression on any hosts species. Lice or tick intensity were not related to naturally occurring scent levels but ticks were less likely to attach to scented objects. My study suggests that when parasitism is low in Crested and Least Auklets the need for a parasite defence is reduced and will obsure any relationship among quality and parasite load.

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