Effects of floral and extrafloral resource diversity on the fitness of an omnivorous bug, Orius insidiosus

Habitat manipulation and increasing biodiversity are important approaches that enhance biological control of pests, but it is important to evaluate the relative benefits of specific plant species when designing conservation programs. Orius insidiosus Say (Hemiptera: Anthocoridae) is an important predator of thrips and aphids that also feeds on plants. It is the target of conservation biological control programs. Despite O. insidiosus' relevance, little is known about the effects of plant subsidies on predator performance or nutritional status. Here, we examined the influence of restricting the pollen and nectar resources of five plant species (alyssum, buckwheat, phacelia, fava bean, and chamomile), and how increasing plant diversity affects O. insidiosus fecundity, survival, and nutritional status. Plant species varied in their suitability for O. insidiosus, which was driven in part by the availability of the pollen or nectar resources. Offering plants as a mixture did not improve fecundity; however, the plant least preferred for oviposition under no-choice tests (fava bean) became the preferred egg-laying site when the plants were offered in combination. We conclude that the benefits obtained by O. insidiosus vary among plant species, and that increasing plant diversity can have unpredicted, positive effects on insect fitness.