April 22, 2016

Examining the Potential Occurrence of Male Mate Choice Behaviors in Acheta domesticus

Ashley Kachmarzinski '16

Mate choice is a major part of an evolutionary phenomenon of sexual selection in which a mate is chosen based on desirable phenotypic traits. It is most common for the female to be the chooser, and the male to be chosen as a mate due to the differences in expenditures of gamete production. Male mate choice, although not a common process, may also exist under specific conditions, where the male is the chooser and the female is chosen as a mate. House crickets (Acheta domesticus) have traits in which they can meet these specific conditions, and thus it is possible for male mate choice to occur. Male house crickets (n = 23) were exposed to large and small female house crickets (n = 46) using simultaneous encounter methods. The results indicate that there were not any statistical differences found between the preference of large and small females (p = 0.3). Other phenotypic traits that show variation in quality, as well as methods of housing are taken into consideration when exploring future research.

Muscle Protein Degradation as a Determinant of Postmortem Interval

Richard Oesterreich '16: TBA

Postmortem interval (PMI), also known as the time since death, is an important aspect of death investigation as it can aid in determining the circumstances of a person’s death. Various methods can be employed in estimating this timeframe, including measuring changes in core body temperature. While most accurate, the temperature method is only useful for up to 12 hours after death. Skeletal muscle proteins are a possible target for the development of a novel approach to accurately estimate PMI beyond 12 hours. Here, polyacrylamide gel electrophoresis (SDS-PAGE), Western blotting, and casein zymography were used to track the degradation of select proteins and enzyme activity in porcine bicep muscle over a period of 240 hours. Cytoskeletal proteins titin, nebulin, desmin, cardiac troponin T, and SERCA1 were found to degrade predictably. Enzymes calpain 1 and 2 also predictably became active. While currently limited by the porcine model and number of proteins used here, these results demonstrate that muscle proteins are promising substrates for future PMI estimation methods.