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Browsing by Author "Shaw, Ashley"

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    Immune response of field crickets (Gryllus firmus) to eugregarine parasites (apicomplexan protoza)
    (2015) Shaw, Ashley; Judge, Kevin; Stock, Michael
    This research concerns the immunity response of the crickets Gryllus firmus. The immunity response is measured by the crickets' encapsulation response, which is a response of the insects blood cells which surround the insect and darken, or become melanized. It is assumed that the higher the melanization, the higher the immune response. The unique feature of these crickets is that they are infected with eugregarine gut parasites, and there has been no previous studies on these parasites within this species of crickets.
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    Immunity, sex and parasites: does sex of sand-field cricket (Gryllus firmus) affect immune response to eugregarine parasites?
    (2016) Shaw, Ashley
    There is controversy about the effects gut-dwelling eugregarine parasites have on their invertebrate hosts. If crickets (Gryllus firmus) apportion resources to reproduction differently in males vs. females, then resources used to mount immune responses to parasites may also differ – especially if the parasites are pathogenic. I investigated the possible differences in immune response between male and female crickets and attempted to determine whether these differences are related to intensity of parasitic infection. To do this, pieces of nylon filament were implanted into the hemocoel of crickets which tested the immune response where hemocytes surround the filament (encapsulation). These responses were compared to intensity of parasitic infection. No statistically significant relationship between sex and melanisation, or sex and parasite load were found. I found that the duration of melanization was negatively correlated to parasite abundance and that there was a positive correlation between body size and parasite number. This result suggests the existence of a relationship between the parasite and host that could be conflicting with sexual selection theory, such as host manipulation by the parasite.