Life cycle of Amblyomma integrum (Acari: Ixodidae) under laboratory conditions.

Abstract

Amblyomma integrum is a hard tick infesting mainly buffalo and cattle and has been identified as an agent of human otoacariasis in Sri Lanka. Data on the life cycle pattern of A. integrum were collected by experimental infestation on New Zealand white rabbits under laboratory conditions. Wild-caught females laid 55-7389 eggs for 2-35days after spending a latent period of 10-25days. Egg incubation period was 31-105days and the newly emerged larvae started feeding after 4-11days. Larvae dropped off after feeding and they moulted into nymphs after 10-16days. Nymphs actively fed on rabbits for 4-8days and dropped off. Engorged nymphs took 11-25days for moulting before emerging as adults. The male:female sex ratio of the adults moulted under laboratory conditions was 11:9. All the stages showed periodicity in engorgement and dropping off. The three-host life cycle was completed within 74-245days with an average of 152.9days. The mean Reproductive Efficiency Index (REI) and Reproductive Aptitude Index (RAI) were 3.6 and 1.1, respectively. Females hatched in the laboratory did not successfully feed on New Zealand white rabbits. The wild-caught females which fed on buffaloes had prolonged pre-oviposition and oviposition periods, low REI, low RAI and low eclosion under controlled laboratory conditions compared to other tick species. Although larva and nymphs of A. integrum successfully fed on New Zealand white rabbits under laboratory conditions, full life cycle was not completed because the adult females did not feed on rabbits.