The dual role of earwigs (Dermaptera) in winter grain crops in Australia

Data associated with Binns et al. (2021) "The dual role of earwigs (Dermaptera) in winter grain crops in Australia":Earwig species have been observed as an irregular pest of increasing concern to farmers growing winter grain crops in Australia over the past decade. In this study, we tested how abiotic and biotic factors influence the feeding behaviour of earwig species. Studies were conducted with two Australian native species, Labidura truncata and Nala lividipes, and the introduced European earwig, Forficula auricularia. We constructed field-based exclusion plots that prevented F. auricularia from moving in or out of a small area of canola. We monitored F. auricularia activity and the feeding damage to canola plants throughout the winter growing season in 2019. In the laboratory, we established microcosms containing crop seedlings, as well as aphids as an alternate food source, to further examine the feeding behaviour of all three species. The native earwigs L. truncata and N. lividipes did not cause any damage to canola or wheat but were found to actively consume aphids when present. We conclude that these species are unlikely to cause significant (economic levels) of pest damage in a field environment. In the microcosm trial, Forficula auricularia caused considerable damage to canola seedlings and consumed aphids readily. We also found that F. auricularia caused damage to canola seedlings early in the winter growing season in the field. However, by the end of the season, F. auricularia presence was associated with increased canola biomass. Forficula auricularia can play an important role in the control of aphids, even in low densities. Furthermore, F. auricularia did not damage canola until all the aphids nearby are consumed. The field and laboratory studies, taken together, show that F. auricularia can be an important predator of aphid pests in canola, indicating a dual role of this species as both a pest and beneficial in winter grain systems.