Master of Science, Miami University, 2012, Zoology

The immune system is critical to an animal's survival. However, changes in immune function during insect development, and the factors that regulate these changes, are not well understood. Hemocytes carry out cellular defenses such as phagocytosis, nodulation, and encapsulation of pathogens. The enzyme phenoloxidase (PO) plays a key role in this process while the enzyme lysozyme breaks down bacterial cell walls. Total PO (TPA) and lysozyme activities, total blood hemocytes, and encapsulation ability were examined from late nymphal stages through early adulthood in the cricket, Acheta domesticus. TPA increased with age while encapsulation ability tended to decrease. The effects of crowding and light stress during nymphal development on adult immune parameters were determined. Crowding increased TPA in crickets housed in small but not large groups. Light stress negatively impacted survival, but not immune function. Further investigation of the effects of early life stress on adult immune function is thus warranted.

Committee: Kathleen A. Killian PhD (Advisor); Nancy G. Solomon PhD (Committee Member); Ann L. Rypstra PhD (Committee Member) Subjects: