Nymphal development on plant vs. leaf with and without prey for two omnivorous predators: Nesidiocoris tenuis (Reuter, 1895) (Hemiptera: Miridae) and Dicyphus errans (Wolff, 1804) (Hemiptera: Miridae)

Nesidiocoris tenuis and Dicyphus errans are important natural enemies of main pests on tomato crops. They are omnivorous predators utilizing both prey and plant resources. However, efforts to investigate their phytophagous rates have been limited. In this study, the potential of both species to develop on tomato leaflet in dish or on caged tomato plant was searched with or without Ephestia kuehniella eggs. Additionally, their nymphal development was evaluated on eggplant leaf. Nesidiocoris tenuis development was further searched on tomato leaflet with greenhouse whitefly nymphs. According to the results, all nymphs of N. tenuis completed their development with prey. The shortest period was recorded on caged tomato plant with E. kuehniella eggs (13.25 days). In the absence of prey, on tomato leaflet, 16.6% of nymphs became adults. In contrast, on tomato plants, all the nymphs completed their development in a period averaging 14.33 days. However, no nymph completed its development without prey on eggplant. The nymphs of D. errans completed their development with prey on a leaflet or on a tomato plant at a percentage of 91.67%, and their developmental period was 16.0 and 17.63 days, respectively. However, none of the nymphs reached adulthood without prey, but on eggplant 13.33% did so, in 22.5 days. Conclusively, E. kuehniella eggs and whitefly nymphs are very suitable prey for N. tenuis. Its potential to develop on tomato without prey was dependent on the plant material offered being successful only when given access to whole plants. Evidence showed its potential to develop on eggplant. Remarkably, D. errans was not able to develop in prey absence on tomato plant or leaflet but showed such a potential on eggplant. The outcomes may improve our understanding of the potential of these two omnivores in biological control in tomato and eggplant crops.