Feeding Behavior of a California Red Scale Parasitoid in Citrus Orchards

Abstract

Many adult parasitoids depend on sugar-rich foods such as nectar and honeydew to meet their energy requirements. Here, we first use HPLC (high performance liquid chromatograph) analyses to assess whether Aphytis melinus DeBach (Hymenoptera: Aphelinidae), the most successful biological control agent of California red scale Aonidiella aurantii Maskell (Hemiptera: Diaspididadae), feeds on honeydew in the field. Our data showed that A. melinus, whose host does not produce honeydew, fed commonly on honeydew from other abundant hemipterans in spring and summer. In a second assay, we studied the longevity of A. melinus when it had access to honeydew excreted by five common hemipterans in citrus: Aleurothrixus floccosus (Maskell) (Aleyrodidae), Aphis spiraecola Patch (Aphididae), Coccus hesperidum L. (Coccidae), Icerya purchasi Maskell (Monphlebidae) and Planococcus citri (Risso) (Pseudococcidae). A. melinus longevity entirely depended on the honeydew source. The longevity of females with access to honeydew excreted by A. spiraecola was similar to unfed females. Contrarily, C. hesperidum and I. purchasi excreted the honeydew with highest nutritional value.