Mass trapping wild Agriotes obscurus and Agriotes lineatus males with pheromone traps in a permanent grassland population reservoir

Abstract

Abstract A study was conducted to determine whether arrays of pheromone traps could be used to reduce populations of male Agriotes obscurus (AO) and Agriotes lineatus (AL) adults in a confined nonfarmed habitat (grassy dyke). Traps placed 3 m apart in 15 × 2 arrays captured significantly more AL than AO, although the trap catch varied with location for both species and was inversely related to the number of nearby competing traps. Models of beetle movement indicated that a considerable proportion of males (AL: 18.4–71.8%; AO: 35.0–58.3%) collected in the arrays had moved in from elsewhere and that AL beetles are more active than AO beetles. AL beetles frequently entered AO traps unless both trap types were present in the array, whereas AO rarely entered AL traps. Concurrent catches in pitfall traps placed inside and outside pheromone trapping zones indicated the trap arrays significantly reduced male (but not female) AO and AL beetles inside their respective arrays, that AO traps reduced AL beetles in AO arrays, and that both AL and AO traps could potentially reduce the number of mating pairs in these arrays. The implications of these results in determining the efficacy of this approach as a click beetle management approach are discussed.