Gryllus pennsylvanicus (Orthoptera: Gryllidae): laboratory weed seed predation and within field activity-density

Laboratory and field studies were conducted during the summer-fall season of 1997 to evaluate the potential of the field cricket Gryllus pennsylvanicus Burmeister as a weed seed predator in annual crops. Laboratory no-choice tests showed that both male and female G. pennsylvanicus readily accepted and consumed seeds of small and large-seeded annual weeds. In 24 h, female and male G. pennsylvanicus consumed an average of 12 and 8 velvetleaf (Abutilon theophrasti Medic.), 26 and 9 giant foxtail (Setaria faberi Herrm.), 87 and 69 crabgrass [Digitaria Sanguinalis (L.) Scop.], and 223 and 90 redroot pigweed (Amaranthus retroflexus L.) seeds, respectively. Tests of pitfall trap sampling in outdoor arenas showed that G. pennsylvanicus is susceptible to this sampling technique. Pitfall traps were subsequently used to monitor activity-density of G. pennsylvanicus in a soybean (Glycine max L. Merr.) field and 2 adjacent perennial filter strips, one composed of switchgrass (Panicum virgatum L.) and the other an alfalfa (Medicago sativa L.) and timothy grass (Phleum pratense L.) mixture. G. pennsylvanicus individuals were first captured in early August, peaked in mid-September, and decreased in October. Field cricket activity-density was greatest in switchgrass filter strip followed by legume-grass filter strip and lowest in soybean.