Date of Award

Summer 1989

Document Type


Degree Name

Doctor of Philosophy (PhD)


Biological Sciences


Biomedical Sciences

Committee Director

D. E. Sonenshine

Committee Member

K. Carson

Committee Member

R. Ratzlaff

Committee Member

M. Rosenthal


Cholesterol oleate was demonstrated to be the cuticular contact sex pheromone of Dermacentor variabilis. This pheromone which has been termed the Mounting Sex Pheromone (MSP) was also demonstrated to be present on the surface of D. andersoni, Amblyomma maculatum and A. americanum. This contact sex pheromone enables males excited and attracted by 2,6-dichlorophenol to identify the female as a potential mating partner. The MSP is the second in the series of three sex pheromones guiding the hierarchy of behavioral responses which constitute tick courtship behavior. Tests with D. variabilis and D. andersoni showed that this pheromone could be removed from and replaced on the surface of female ticks as well as transferred to inanimate objects without the loss of male responsiveness. Cuticular ridges, present on the female cuticle were shown to be unimportant as a sex recognition cue. The size of the female was also shown to be not of primary importance in assisting the male in mate recognition.

Cross reactivity was demonstrated particularly within genera and was also demonstrated between genera. The cross reactivity may be related to the presence of sterol esters on all the species of female ticks examined.