Doru luteipes action against Spodoptera frugiperda

In Brazil, the common earwig Doru luteipes (Scudder) (Dermaptera: Forficulidae) is considered an important biocontrol agent for the maize crop, consuming the fall armyworm Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae) eggs and caterpillars from 1st to 3rd instar. Despite this, several aspects of the interaction between both species have not yet been studied. We aim to evaluate the non-consumption effects of earwigs on the oviposition of moths, the earwig’s predatory preference between eggs and neonates and its functional response on S. frugiperda eggs. In no-choice tests between plants with or without the presence of the predator, S. frugiperda moths deposited a smaller number of eggs on plants with risk of predation. In choice-based tests, earwigs initially attacked newborn caterpillars, but preferred to feed on eggs. Males and females fed more on eggs with increasing supply density and consumption was adjusted to the type II functional response curve. D. luteipes males were more efficient predators than females when exposed to higher egg densities. These findings clarify aspects of the predatory role of D. luteipes on S. frugiperda that had not yet been addressed and confirm that the earwig is an important biological control agent, potentially capable of impacting the colonization and population growth of S. frugiperda in maize crops, if there were conditions favorable to its early arrival.