Friend or foe? Revealing the omnivorous feeding behavior of the ring-legged earwig on brassicas

This study examined the hypothesis that the herbivory of Euborellia annulipes positively affects its biological traits, with variations based on the cultivated species of Brassica and the availability of essential food sources. The provision of plant material (leaf pieces) from the Brassica species pak choi cabbage, Portuguese cabbage, cabbage, and radish did not improve the biological performance of the earwig compared to a diet without plant material. Nevertheless, 66.0% and 43.3% of the second instar nymphs that solely consumed pak choi cabbage and Portuguese cabbage, respectively, completed their development successfully. Herbivory by E. annulipes on brassicas occurred both in the presence and absence of a diet, although it was significantly more pronounced when no other food sources were available. Among the four Brassica species studied, pak choi cabbage exhibited the highest feeding frequency and consumption rate. However, pak choi cabbage grown under controlled conditions and exposed to multiple releases of earwigs showed no reduction in productivity.