The behavioural responses of three different strains of Musca domestica (Diptera: Muscidae) to Alfacron bait in the laboratory

Abstract

AbstractA study was carried out to investigate the behavioural components of resistance in the Standlake strain of Musca domestica Linnaeus. The flies were collected from a poultry unit where azamethiphos spray-on-bait (Alfacron), had been regularly used to control the fly population. A no-choice laboratory cage test was used to observe the responses of the Standlake resistant strain to baits and compare it with two other strains namely, Sparsholt resistant and Cooper susceptible. The baits used were, Alfacron, sugar and analytical grade azamethiphos, sugar alone, and a blank target as control. Only female flies were used, each strain was exposed separately to each bait over a 50 minute period and the responses were recorded with a datalogger. The responses (per fly) recorded during each test period were: the number of visits to a bait; the time spent on a bait; the number of feeds and time spent feeding on the bait defined as the number of proboscis contacts and the length of time of proboscis contact with the bait. Knockdown of flies was recorded at the end of each test. All strains showed differences in their responses to baits. The Standlake strain showed the greatest difference to responses to Alfacron, with inhibition of proboscis extension when flies landed on the bait and a lower proboscis contact when extended, resulting in fewer flies being knocked down by Alfacron than by the sugar and azamethiphos bait. This suggested that inhibition of feeding on the Alfacron bait by the Standlake strain was caused by formulation components or contaminants and not the active insecticide ingredient, azamethiphos.