A technique for the topical application of poisons to non-anaesthetised house-flies for knockdown assessments.

Abstract

An apparatus and technique are described for handling, immobilising by suction, and individually dosing house-flies, Musca domestica L. The apparatus consists of a suction platform connected to a vacuum cleaner, a specially designed cage and a measured-drop apparatus. The suction platform consists essentially of a circle of terylene gauze, on to which the flies are drawn from the cage and held by suction during treatment. The cage can be made to contract, so that the flies may be crowded together near the special emergence hole through which they are to be withdrawn. The technique avoids the use of cooling and anaesthetics, which affect the metabolism of the flies, and is therefore especially suitable for measuring knockdown, although it can equally be used to estimate toxicity. Some factors likely to influence the results are examined and discussed, and an example is given of two experiments with house-flies, to show that the method gives reproducible results.