Effect of temperature on Hyalomma (Hyalomma) dromedarii Koch (Acari: Ixodidae).

Abstract

The effects of 21, 25, 29, and 34°C on developmental period, weight of different stages in the life cycle, and conversion efficiency in Hyalomma (H.) dromedarii Koch were investigated at 75% relative humidity. Egg incubation, nymphal premolting, and female preoviposition and oviposition periods were prolonged with decrease in temperature. However, the egg incubation and preoviposition periods were most greatly affected. Larvalnymphal and female feeding periods of this two-host tick were not affected by temperature. The percentage of loss in larval weight before feeding was greater at 34°C, and female weight was greater at 29 and 34°C, than at the lower temperatures. During molting, nymphs lost the greatest percentage of their weight at 34°C. Fifty percent of the eggs were deposited within 6.4, 5.2, 5.5, and 3.4 d and 90% within 16.0, 10.8, 10.8, and 7.7 d at the tested temperatures, respectively. The conversion efficiency of female weight to egg mass weight (73.4–79.4%) was not affected by temperature. The results are compared with those obtained under similar experimental conditions for H. impeltatum and are discussed in relation to information on other ixodid ticks.