Macrolophus pygmaeus (Hemiptera: Miridae) foraging on tomato leaves from different plant strata

This study investigates the foraging activity of the generalist predator Macrolophus pygmaeus (Rambur) (Hemiptera: Miridae) on tomato leaves of different vertical plant strata (apex, top, middle and lower). On a leaflet of each tested leaf, ten 2nd instar nymphs of the aphid Myzus persicae were established with the aid of harmless glue, as prey. It was observed that prey consumption was highest on the lower leaves. There was no significant difference in prey consumption between middle and top leaves but it significantly reduced on the apex leaves as compared to the top and the lower leaves. Behavioural observations were conducted to assess the time budgets (i.e. time spent in each activity such as searching, resting, grooming) of the foraging predator on leaves of each plant strata. The predator spent significantly more time in grooming on apex than on lower leaves whereas it showed a higher tendency to fall off from the apex leaves than the leaves of the other plant strata. The apex leaves had the highest trichome density and this may impede movement of the predator. In the third experiment, the prey consumption of M. pygmaeus nymphs was reduced with the increase of distance between its release point and the prey patch on a tomato plant. In conclusion, M. pygmaeus nymphs are most efficient in foraging on the middle or lower leaves of young tomato plants whereas their prey searching efficiency is influenced by the distance between their release point and the prey patch. Therefore, the efficacy of M. pygmaeus nymphs in pest control may be benefited if released close to prey patches but not on the apex leaves.