Natural enemies of pests are employed to control pests and increase yield in agriculture. However, natural enemies may be antagonistic toward one another. Past studies have shown that multiple natural enemies can either improve biocontrol or conversely engage in intraguild predation that releases the pests from trophic control. Knowledge of the conditions underlying these contradicting consequences is crucial to biocontrol success. Here I present a case where intraguild predation involving a self-limiting intermediate predator improves prey suppression. A season-long manipulative field experiment was conducted in cotton to evaluate the performance of the generalist intermediate predator Geocoris pallens Stäl on controlling the pest, Lygus hesperus Knight and the effects of intraguild predation from a top predator, Zelus renardii Kolenati.
Results/Conclusions
Results show that G. pallens provided noticeable biocontrol of L. hesperus and the addition of Z. renardii significantly strengthened this biocontrol. G. pallens alone did not improve cotton fruit retention, but inclusion of Z. renardii did. Despite abundant food and absence of predators, G. pallens female adult numbers in the ‘G. pallens only’ treatment did not increase from the introduced level and were similar to those in treatments with Z.renardii predation. This suggests self-limiting characteristics within G. pallens population that could have contributed to the improved prey suppression through intraguild predation.
