The effects of different prey regimes on the proteolytic digestion of nymphs of the spined soldier bug, Podisus maculiventris (Hemiptera: Pentatomidae)

The effects of different prey regimes on the performance and digestive physiology of the spined soldier bug, Podisus maculiventris (Say) (Hemiptera: Pentatomidae), were assessed. Specifically, P. maculiventris nymphs were fed on Colorado potato beetle (CPB), Leptinotarsa decemlineata Say (Coleoptera: Chrysomelidae), larvae; Egyptian cotton leafworm (ECW); Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae); larvae; Calliphora spp. (CAL) (Diptera: Calliphoridae) pupae or a mixture of the three prey. No differences in development and weight gain were observed when P. maculiventris nymphs were fed different prey species (CPB, ECW or CAL). However, an increase in weight gain and a reduction in the duration of the stadia were observed for nymphs fed with a mixture of the three prey. To investigate the physiological background, biochemical analysis were carried out on insects dissected at the end of the feeding assay. We have found that the proteolytic activity in the salivary glands of P. maculiventris nymphs was not affected by prey species, whereas the relative activity of these proteases in the midgut depends on the prey. Moreover, gel assays proved that the proteolytic profiles of midguts from P. maculiventris nymphs feeding on CPB, ECW and CPB closely resembled those of their prey. All together, these results suggest that P. maculiventris may utilize enzymes from the prey they consume that may facilitate the process of digestion.

Conditions for Short-Term Storage of Field-Collected Spined Soldier Bug, Podisus maculiventris (Say) (Heteroptera: Pentatomidae), Adults Prior to Augmentative Release1

The date at which spined soldier bugs, Podisus maculiventris (Say) (Heteroptera: Pentatomidae), can be trapped for augmentative release against overwintered Colorado potato beetle, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae), may be up to 5 wks earlier than the date of peak Colorado potato beetle emergence, necessitating storage of field-collected spined soldier bugs prior to release. The effects of temperature, photoperiod, and food on spined soldier bug survivorship and fecundity during and after a 5-wk storage period were investigated. In general, unfed spined soldier bugs had greater mortality and reduced fecundity compared with those fed string beans and mealworm larvae during storage. Temperature and photoperiod generally had no effect. However, female spined soldier bug survivorship was greater among unfed insects stored at 5°C compared with those stored at 15°C. Therefore, household refrigerators can be used for short-term storage of field-collected spined soldier bugs. Even when stored spined soldier bug females are fed, fecundity is low (14 nymphs per female originally collected). This may limit the use of field-collected spined soldier bugs for augmentative release against Colorado potato beetle to relatively small plantings of potatoes.