Actographic Analysis of the Effects of an Esterase Inhibitor on Male Moth Responses to Sex Pheromone

Abstract

The effects of 3-octylthio-1,1,1-trifluoropropan-2-one (OTFP), a trifluoromethyl ketone that inhibits antennal esterases, on male Mamestra brassicae responses to the main pheromone component have been investigated using an actograph. This actograph used a movement detector based on the Doppler effect. The signal from the detector was digitalized and analysed on a PC microcomputer to quantify male activity. When added to the air flowing through the observation chamber, OTFP inhibited the responses of male moths to the pheromone. The number of males responding to the pheromone and the intensity of the response were decreased by OTFP. The latency of the response was increased and its duration decreased. These effects on the kinetics of the behavioural response cannot be directly correlated to the inhibition of pheromone catabolism by OTFP and other targets must be involved. The high level of inhibition of behaviour observed in presence of OTFP demonstrates the interest of trifluoromethyl ketones as mating disruption agents for pest control.

On the use of microwave radar devices in chronobiology studies: An application withPeriplaneta americana

“…These actometers have been shown to be sensitive enough to record flight and locomotor activity of individual insects such as tsetse flies (Van der Goes van Naters, Den Otter, & Maes, 1998), moths (Den Otter, De Cristofaro, Voskamp, & Rotundo, 1996;Renou, Berthier, Desbarats, Van der Pers, & Guerrero, 1999), Anopheles mosquitos ( Van de Broek, Den Otter, & Van der Pers, 1999), and fruit flies (Knoppien, Van der Pers, & Van Delden, 2000). In the present study, we describe a homemade microwave radar device for monitoring locomotor activity in insects and small mammals.…”

Disruption of responses to pheromone by (Z)‐11‐hexadecenyl trifluoromethyl ketone, an analogue of the pheromone, in the cabbage armyworm Mamestra brassicae

“…Bioassays were carried out using an actograph already described15 and consisting of a glass olfactometer and a radar detector. Briefly, the olfactometer consisted of a cylindrical observation chamber (120 mm length × 30 mm ID), with an upwind air inlet of smaller diameter (6 mm ID) that was connected to a permanent source of charcoal‐filtered air (85 litre h −1 ).…”

“…Relevant behavioural parameters were determined after repeated observations of the behaviour of male M brassicae in the actograph (unpublished data and Reference 15). After pheromone stimulation, males became very active, performing wing fanning and intense locomotion in the observation chamber.…”

“…After pheromone stimulation, males became very active, performing wing fanning and intense locomotion in the observation chamber. Both activities are typical of male moth precopulatory behaviour and they were easily detected by the radar sensor, producing bursts of high amplitude spikes 15. Males usually maintained a high level of locomotory activity for several minutes after the stimulation, but short pauses within a response enabled the discrimination of individual bursts of activity.…”

“…The pheromone receptor system of M brassicae has been well characterized 14. Males respond to Z11‐16:Ac by wing fanning and intense locomotion 15. Thus, this species was a suitable model to investigate further the effects of a fluorinated pheromone derivative on the behavioural response of male moths to pheromone when diffused in the air.…”