The effects of honey as a dietary supplement on the survivorship and nutrition-storing capacity of Hemiptarsenus varicornis (Hymenoptera: Eulophidae), a parasitoid of Liriomyza (Diptera: Agromyzidae) leafminers

Availability of non-host food can determine the success of biological control through its effects on parasitoid survivorship. Here, importance of adult food in determining the longevity of Hemiptarsenus varicornis (Girault), a biological control agent of the pest leafminers Liriomyza trifolii (Burgess) and L. sativae Blanchard, was examined by means of laboratory experiments. Male and female H. varicornis lived less than 2 days with only water available. Provision of diluted honey improved the longevity of adult H. varicornis. Females benefited more by feeding on diluted honey than did males, extending their lifetime to around 2 weeks. In another experiment, newly emerged females were fed diluted honey for their first 5 days and with water only for their remaining lifetime. The result showed that both male and female H. varicornis lived no longer than 2 days after diluted honey was withheld, indicating that nutritional reserves that they could store were highly limited. Thus food sources should be continuously available in the environment for their reproduction. The implications of the results are discussed in the context of biocontrol of leafminers in greenhouses.