| Popis: |
Thrips attacks different types of plants including buds, leaves and flowers where, heavy pest infestation can degrade the quality of the agricultural products that can reach the half. The study aimed to improve the understanding of prey-predator interaction between Orius albidipennis nymphs and Thrips tabaci nymphs and the degree of the response of the predator change when they feed on different prey densities. The predator O. albidipennis nymphs were collected from the colony reared in the Biological Control Res. Dep. ARC. Giza, Egypt, and starved for 4 h in glass vials containing small wet cotton with water without preys. Thrips tabaci nymph were introduced as prey into small Petri dishes at three densities (10, 20 and 30 nymphs), respectively. Starved predators were transferred to the experimental arena using smooth hair brush. The number of dead or live nymphs was counted. 25 replicates of each prey density were performed. The results showed that at densities of 10, 20, and 30 nymphs per arena, the consumed prey significantly increased with increasing prey density. When only 10 thrips nymphs were provided, O. albidipennis consumed a mean of 6.8±1.2 thrips nymphs per predator per day, even when 20 thrips nymphs were provided the consummation increased to 15.1±1.7 and increased to 26.5±2.9 when 30 thrips nymphs were provided, as a result, the obtained data indicates that the predators can efficiently find the thrips nymphs at low densities. However, the handling time (Th) of O. albidipennis which is sometimes consider as a good indicator of the predation rate that was the shortest at third nymphal instar than first nymphal instar when fed on nymphs of T. tabaci, respectively. The results demonstrated the calculation of the attack rate (a) and handling time (Th) significantly declined as stages reseed. |
