Calling Behavior in Female Western Corn Rootworm Beetles (Coleoptera: Chrysomelidae)

Abstract

A postural display by female western corn rootworm beetles, Diabrotica virgifera virgifera LeConte, was examined in relation to age, mating, and time of day and characterized as a calling or sex pheromone-releasing behavior. Calling was observed in the laboratory on the day that teneral females emerged from the soil, although frequency of the behavior did not peak until a day later. Females called throughout the day but were most active during the first half of photophase on a photoperiod of 14 :10 (L :D) h. Virgin females mated significantly faster and in greater numbers if they had recently engaged in calling activity. Most females ceased calling within 24 h after insemination. Volatiles collected from calling females and used to bait sticky traps exposed in corn fields were significantly more attractive to feral western and northern corn rootworms, D. barberi Smith & Lawrence, than were volatiles from females that did not call. Responses to the latter differed little if any from responses to controls collected from apparatus without females.