Experimental aspects of life cycles of two hard tick species, <em>Rhipicephalus (Boophilus)</em> and <em>Hyalomma isaaci</em> (Acari: Ixodidae), on New Zealand white rabbits

Abstract

Hyalomma isaaci and Rhipicephalus microplus are two common hard tick species infesting buffalo and cattle. Biological data on the ticks' life cycle were collected by experimental infestation on New Zealand white rabbits (Oryctolagus cuniculus) under controlled conditions (70%-80% Relative humidity and 27 ± 1 ᵒ C Temperature). Life cycle parameters including latency period, oviposition, feeding, moulting periods were determined and the Mean Reproductive Efficiency Index (REI) and Reproductive Aptitude Index (RAI) were calculated. Females of H. isaaci and R. microplus started oviposition after 3-14 days and 5-8 days, respectively. Hyalomma isaaci laid 15-6,166 (1600.8 ± 1940.9) eggs in 1-24 days while R. microplus laid 19-1,535 (434.2±344.8) eggs in 1-11 days. Emerged larvae of H. isaaci spent 19-47 days in incubation and moulted on-host. Nymphs dropped after feeding for 15-21 days, subsequently taking 14-18 days to moult into adults. Females fed for 8-10 days, and reached a maximum engorgement weight of 127.0 mg. The non-parasitic phase of R. microplus was 29-57 days, while the parasitic phase was confined only to larval engorgement and moulting into nymphs taking of 8-14 days. The REI/RAI was 7.1/3.6 and 8.3/5.1 for H. isaaci and R. microplus, respectively. Hyalomma isaaci completed its two-host life cycle within 62-166 days while R. microplus could not complete its life cycle because the nymphs did not feed on rabbits and therefore, none of them moulted into adults. The New Zealand white rabbit was not an appropriate laboratory host for the mature stage of R. microplus even though it was a suitable host for H. isaaci.