Several factors affect organisms involved in carrion decomposition, an ecological service where nutrients from heterotrophic biomass is recycled back into the ecosystem. Understanding how such factors impact these organisms can provide further insight into carrion ecology, but also has forensic applications. Blow flies (Diptera: Calliphoridae) are commonly collected from remains and used to estimate the post-colonization interval. To do so, blow fly specimen age must first be estimated based on size or developmental progress using reference data. However, these are often collected in the laboratory and do not account for stressful factors that may affect the development of immatures on remains. Thus, understanding how stressful factors impact size and developmental progress is needed to provide accurate estimates of blow fly specimen age. Understudied factors include predation, infection, and heat shock.
Predation of blow fly immatures is well documented in the literature, but the impact of injury arising from unsuccessful predation attempts on blow fly life history traits is understudied. In addition, acute exposure to high temperatures are possible as ambient temperatures above 40°C have been recorded in many localities. Therefore, the impact of these two factors on several life history traits of Cochliomyia macellaria (Fabricius) (Diptera: Calliphoridae) were examined. Larvae were exposed to an aseptic or septic wound and/or heat shock in the laboratory and were monitored until eclosion. Injury, septic wounds, and heat shock had a significant effect on life history traits, but heat shock had the greatest impact.
To investigate whether larval knockdown temperatures are detrimental to mutualistic microbes associated with the larvae, thermal profiles were produced for five species of bacteria associated with forensically significant insects and decomposition. All five species had upper thermal limits below larval knockdown temperature while the base temperature was greater than 0°C for only four species. These results provide support that acute exposure to high temperatures may be detrimental to mutualistic microbes associated with larvae. Furthermore, it challenges the assumption in forensic microbiology that all bacteria have a base temperature of 0°C. Overall, results of this thesis indicate that periods of heat stress can alter decomposition processes and related forensic applications.
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