Term of Award

Spring 1990

Degree Name

Master of Science in Biology

Document Type and Release Option

Thesis (restricted to Georgia Southern)

Committee Chair

James H. Oliver, Jr.

Committee Member 1

William S. Irby

Committee Member 2

John A. Rafter

Committee Member 3

Sara Neville Bennett

Committee Member 4

Wayne A. Krissinger

Abstract

Mus musculus , the house mouse (laboratory strain), Peromyscus gossypinus. the cotton mouse, Eumeces laticeps. the broad-headed skink, and Cavia porcellus, the guinea pig, were successively infested five times with larvae of Ixodes scapularis. the blacklegged tick. Tick feeding success, engorgement weight and molting success were measured after each infestation. In general, a greater percentage of ticks (P<0.05) fed on M. musculus and E. laticeps than on P. gossypinus or Q. porcellus. P. gossypinus expressed partial resistance, measured in percentage of ticks feeding, during the third infestation, but showed increased tolerance during the fourth and fifth infestations. None of the larvae exposed to Q. porcellus fed after the third infestation. Overall, ticks fed on E. laticeps were heavier than those fed on all the other hosts (P<0.05). Ticks that fed on M. musculus were always slightly heavier than those fed on P. gossypinus. though the differences were not always statistically significant at the 5% level. Although only 1.6% of larvae from the third infestation and none from later infestations of Q. porcellus engorged, engorgement weights of larvae from first and second infestations were higher (P<0.05) than those of M. musculus and P. gossypinus and lower (P<0.05) than those from E. laticeps. A greater percentage of larvae from E. laticeps and M. musculus (P<0.05) molted to nymphs compared to those from P. gossypinus and C. porcellus. Tick molting success was the same for ticks fed on

P. gossypinus and for ticks fed on C. porcellus during the first and second infestations. Neither M. musculus, P. gossypinus nor E. laticeps expressed any resistance (measured as percent feeding, engorgement weight and molting) to feeding by I. scapularis larvae after 5 infestations. Host serum was tested using an ELISA test for antibodies against I. scapularis salivary gland antigens prior to and after each infestation. Only C. porcellus tested positive for antibodies against I. scapularis salivary gland antigen. A positive titer was detected after the second infestation and throughout the rest of the experiment.

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