LE3 .A278 2020

2020

Smith, Todd

Acadia University

Bachelor of Science

Honours

Biology

Biology

Previous studies found that Culex territans mosquitoes prefer to feed on green frogs (Rana clamitans) with high infections of Hepatozoon blood parasites, compared to those with low infections or those that were uninfected, and that mosquitoes were more attracted to certain species of cultured bacteria isolated from the skin of green frogs. Our working hypothesis was that differential communities of bacteria on the skin of frogs with high infections produced volatile compounds that are attractive to mosquitoes that vector this parasite. The first objective was to isolate culturable bacteria from the skin of green frogs at three different Hepatozoon infection levels (uninfected (0%), low (<1.5%) and high (>1.5%), and identify them using 16S small subunit ribosomal ribonucleic acid (SSU rRNA) sequences. Significant differences in the number of culturable bacteria per frog were not found between the infection levels. Frogs featured bacteria that were restricted mostly to their infection level, and infected frogs featured more pathogenic bacteria than uninfected frogs. The second objective was to determine the diversity and abundance of volatile compound from whole frogs and bacteria using dynamic headspace and solid phase microextraction (SPME), that were analysed using gas chromatography-mass spectrometry (GC-MS). Significant differences were found when comparing volatiles produced from frogs at each infection level, with a higher abundance and diversity of volatiles from infected frogs than uninfected frogs. The third objective was to record neurophysiological responses of C. territans to volatiles from whole frogs using gas chromatography-electroantennographic detection (GC-EAD). Although C. territans have strong responses to standard compounds (e.g., ethanol, acetoin, and geosmin), responses to volatiles from frogs could not be recorded due to experimental challenges.

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https://scholar.acadiau.ca/islandora/object/theses:3448