Studies on the surface ultrastructure of a snake tick, Amblyomma helvolum (Acari: Ixodidae)

Abstract

A detail surface ultrastructure study on both male and female Amblyomma helvolum, inhabiting on snakes were made by using scanning electron microscope. The study unraveled the clear sexual dimorphism of the tick. Details of the surface ultrastructure were compared with other ixodid tick species as reported so far. Some distinctive surface morphology of A. helvolum was recorded viz., arrangement of hypostomal dentition, pore distribution on scutal surface, presence of festoons, position of male and female genital organ, number of spurs on different appendicular coxa, structure of spiracle and Haller’s organ, number of sensilla on anterior pit of Haller’s organ and distribution of different ventral idiosomal plates were remarkably diverse between sexes. Absence of festoons at the posterior extremity of female tick and absence of eyes on the antero-lateral sides of the scutum of both sexes of this tick species are the main outcome of this present study, which may provide insight to the traditional identification key of the genus Amblyomma.