Attractiveness and nutritional effects of flowers on the survival of a dipteran pest and its parasitoids

Abstract

Flower addition is commonly used worldwide to benefit parasitoids and improve conservation biological control of pests. However, biological control enhancement via flower addition depends on both flower attractiveness and the responses of parasitoid and pest species to flower resources. Here, we experimentally compared the effects of two Apiaceae flowering species (Conium maculatum and Coriandrum sativum) with those of water, honey and no resource treatments on longevity and survival of adults of the leafminer Liriomyza huidobrensis and two hymenopteran parasitoids (Chrysocharis flacilla and Phaedrotoma scabriventris). We also examined the attractiveness of flowers of both plant species to the leafminer and P. scabriventris adults. The provision of flowers increased longevity and survival of the three insect species with respect to water and no resource treatments. The effects of honey on longevity were similar to or even higher than those of flowers, depending on the insect species, whereas water only increased the longevity of P. scabriventris in relation to no resource treatments. In attractiveness trials, P. scabriventris preferred C. maculatum flowers, whereas L. huidobrensis showed no preference for flower species. Our findings indicate that both plant species have potential as floral resources in biological control, since two parasitoid species benefited from flowers. However, these plant species must be cautiously considered because L. huidobrensis also improved its fitness when provided with both floral resources. The present work highlights the need to simultaneously study parasitoid and herbivore food needs and flower attractiveness, especially in dipteran pests, in order to achieve a successful biological control.