Ultrastructural Analysis of the Oocytes of Female Rhipicephalus sanguineus (Latreille, 1806) (Acari: Ixodidae) Ticks Subjected to the Action of Azadirachta indica A. Juss (Neem)

The present study provides ultrastructural information about the acaricidal effects of neem (Azadirachta indica A. Juss) on the ovaries of R. sanguineus engorged females. In general, the main damage caused in the oocytes was alteration in the shape of the cell and of the germinal vesicle, ring-shaped nucleolus, cytoplasmic vacuolation, and disorganization of the organelles and of the cell membranes (including the chorion), all of which indicate that these cells could be in the process of death. The results showed that azadirachtin would be an efficient acaricide agent for inhibiting and/or neutralizing the reproduction process of R. sanguineus females, impairing the reproductive ability of this species.