Pheromone Studies of the Two spotted Spider Mite. 2. Behavioral Response of Males to Quiescent Deutonymphs12

Abstract

Adult male Tetranychus urticae Koch were attracted to quiescent female deutonymphs with the onset of quiescence. The consistency of male attraction varied from 40–85% during the early part of the period and gradually increased to 80–100% prior to adult emergence. Average duration of the quiescent period was 40.4 hours at 24°C and 23.4 hours at 30°C. Occasional males were found that did not respond consistently to quiescent deutonymphs. The cause was not determined. Male attraction was greater at 30°C and 20–30% relative humidity than at 30°C and 90–95% relative humidity. Trials at 24°C and 20–30% relative humidity were intermediate. It was concluded that tests for bioassay of T. urlicae female sex pheromone could be conducted at 30°C and 20–30% relative humidity but should include sufficient replications to measure erratic male behavior.