Theses and Dissertations
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- All Subjects: Ecology
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- All Subjects: Social Psychology
Locusts are generalist herbivores meaning that they are able to consume a variety of plants. Because of their broad diet, and ability to respond rapidly to a favorable environment with giant swarms of voracious insects, they are dangerous pests. Their potential impacts on humans increase dramatically when individuals switch from their solitarious phase to their gregarious phase where they congregate and begin marching and eventually swarming together. These swarms, often billions strong, can consume the vegetation of enormous swaths of land and can travel hundreds of kilometers in a single day producing a complex threat to food security. To better understand the biology of these important pests we explored the gut microbiome of the South American locust (Schistocerca cancellata). We hypothesized generally that the gut microbiome in this species would be critically important as has been shown in many other species. We extracted and homogenized entire guts from male S. cancellata, and then extracted gut microbiome genomic DNA. Genomic DNA was then confirmed on a gel. The initial extractions were of poor quality for sequencing, but subsequent extractions performed by collaborators during troubleshooting at Southern Illinois University Edwardsville proved more useful and were used for PCR. This resulted in the detections of the following bacterial genera in the gut of S. cancellata: Enterobacter, Enterococcus, Serratia, Pseudomonas, Actinobacter, and Weisella. With this data, we are able to speculate about the physiological roles that they hold within the locust gut generating hypotheses for further testing. Understanding the microbial composition of this species’ gut may help us better understand the locust in general in an effort to more sustainably manage them.
This study tested the effect of status threat on ingroup identification and examined identity concealability and stereotype endorsement as moderators of the relationship. Participants included a visible identity group (Asian men) and a concealable identity group (gay men). Participants were randomized into either a status threat condition, in which they read a vignette that reminded them of a negative stereotype about the target group and discussed positive stereotypes of the group as well, or a control condition that discussed positive stereotypes only. Participants then responded to a measure of ingroup identification and a measure of stereotype endorsement. A significant main effect of status threat on ingroup identification was found, such that participants in the status threat condition showed lower ingroup identification. The interaction of condition and concealability was not significant. The interaction of condition and stereotype endorsement was marginally significant, such that the main effect shows up stronger for those lower on stereotype endorsement. The main effect is interpreted as a potential protective strategy for self-esteem. The stereotype threat interaction is interpreted as a difference in the way that those who do and do not endorse the stereotype view the legitimacy of the status threat.