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Y Rechav

Publications and source records attributed to Y Rechav.

61 records · Page 4Linked to original sources

Life cycle of the tick Rhipicephalus evertsi evertsi neumann (acarina: ixodidae) under laboratory conditions.

The preoviposition period of the tick Rhipicephalus evertsi Neumann maintained under laboratory conditions at 26 C was 6.1 +/- 0.38 days. The average number of eggs produced during the oviposition period was 10,400 +/- 397 (max. 13.307, min. 7,558). The greatest daily egg production was recorded on the 3rd day (1.107 eggs/female). The incubation period of eggs at 26 C was 24.8 +/- 1.37 and the feeding time of the larvae and nymphs (a two-host tick) was 17.2 +/- 0.14 days at 26 C. This tick represents the two-host type of cycle and the percentage of larvae, pharate nymphs, and nymphs on the host at various intervals after attachment was recorded. The changes in the weight of the immature stages during the feeding period was examined daily. Nymphs which produce males were lighter in weight (10.3 +/- 0.28 mg), than those which produce females (15.6 +/- 0.33) and males emerge (13.7 +/- 0.10 days of premolting period) before females (14.1 +/- 0.11 days).

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The effects of tick numbers and intervals between infestations on the resistance acquired by guinea-pigs to adults of Rhipicephalus evertsi evertsi (Acari: Ixodidae).

Guinea-pigs were infested three times at short (1 week) intervals or long (10 week) intervals between successive infestations with low (1), medium (8) and high (15) numbers of adult Rhipicephalus evertsi evertsi. To compare the resistance developed by the hosts at short and long intervals between infestations, a challenge (fourth) infestation was performed with the high number of ticks. Resistance was assessed by comparing the mean weight of engorged female ticks that dropped from the hosts. Concentrations of beta globulins in the host sera were also monitored. Different tick loads (low, medium and high) and infestation intervals had a similar influence on the reduction in weight of the females which was between 60-70% after the final challenge. However, the concentration of beta globulins, was highest in the guinea-pigs exposed to medium and high numbers of ticks with long infestation intervals, probably because of an increase in the production of protective antibodies in response to more intensive antigenic challenge. The relationship between engorgement weight and beta globulin levels in host sera is discussed.

Animals↗