Concentration-dependent detection of imidacloprid in behaviorally resistant house flies (Musca domestica L.)

The house fly (Musca domestica L.) is a cosmopolitan and synanthropic pest fly species commonly associated with confined animal facilities. One of the most common methods for house fly control is the use of insecticides, but insecticide resistance is an increasing problem due to the over-application of insecticides and lack of rotation among insecticidal chemical classes. House fly resistance to imidacloprid, the most widely used neonicotinoid insecticide available for fly control, has evolved through physiological and behavioral mechanisms in field populations. Behavioral resistance to imidacloprid was documented in a field population of flies from a southern California dairy, though the resistance was not uniform among individuals in the population. Flies were selectively bred for behavioral resistance to imidacloprid without increasing the physiological resistance profile of the selected flies, and behavioral, genetic, and genomic analyses were completed.

In previous studies, behavioral resistance to imidacloprid was evaluated using a high concentration of imidacloprid (4,000µg/g). It was unknown if behaviorally resistant house flies had the ability to detect or would exhibit aversion to lower concentrations of imidacloprid. The current study examined behaviorally resistant house flies’ ability to detect and decern between variable concentrations of imidacloprid formulated in sucrose. Results from the studies will be discussed in further detail.