The effect of floral resources on predator longevity and fecundity: A systematic review and meta-analysis

Floral resources are increasingly used in conservation biological control to support natural enemies of insect pests. However, the dietary value of floral resources in supporting predatory arthropods, including their effect on longevity and fecundity has not yet been systematically reviewed. To comprehensively evaluate this, the presented review summarizes published studies on the effect of various floral resources (flowers, pollen, and sugar solution (as a proxy for nectar)) on predatory arthropods. We identified 70 articles, including 628 trials, which measured predator longevity (3 4 7) and fecundity (2 8 1) when supplied with floral resources, as compared to a water only control. Across predator species, results showed that floral resources significantly increased predator longevity, especially whole flowers and sugar solution. Pollen could also prolong predator longevity but was less effective than sugar solution and flowers. The effect of flowers varied greatly among plant species, with those having open or exposed nectaries being more likely to prolong predator longevity, supposedly due to higher accessibility. Some predator species could oviposit on a diet consisting only of floral resources. The findings in the present study emphasize the value of floral resources on supporting predators. Predatory arthropods' biological control services could be enhanced by choosing plants that favor them in conservation biological control programs.