Effect of 25-azacholestane on Argas (Argas) hermanni (Ixodoidea:Argasidae)

Unfed and fed nymphal Argas hermanni Audouin were treated topically with 1, 5, 10, 15, and 20 micrograms of 25-azacholestane. The azasteroid did not inhibit feeding but had a dose-related lethal effect on unfed nymphs. Generally, it had little effect on nymphs treated after feeding. The 10-micrograms dose reduced the premolting period of nymphs treated before feeding. Some adults emerging from the 5- to 20-micrograms dosage groups that had been treated before feeding failed to shed their exuvia and others also had deformed legs. Greater numbers of adult females emerged from nymphs treated before feeding. The preoviposition period was almost the same in control females and of female mates, with males emerging from treated nymphs. Females from nymphs treated before feeding have a prolonged preoviposition period. Fecundity was reduced when males were treated with 10-20 micrograms as unfed nymphs. Egg hatch was reduced for females treated with 15 and 20 micrograms as fed nymphs, females treated with 5 and 10 micrograms as unfed nymphs, and as progeny of males treated with 10 micrograms as unfed nymphs. Results suggest possible interference with juvenile hormone titer in treated ticks.