27 Ara 2024 Cuma
Investigation on prey preference and switching behavior of the predatory bug, Orius niger Wolff under laboratory conditions (Het.: Anthocoridae)
Abstract :Prey preference and switching behavior of Orius niger on three preys, Thrips tabaci, Aphis gosssypii and Tetranychus urticae were examined. Ephestia kuehniella Zeller eggs, corn pollen and green bean pods were used as food and oviposition sites, respectively. Experiment was carried out under laboratory condition (25±1°C and 65±5% RH, with a 16:8 L: D photoperiod). Four to six days old females of the predatory bug was used in experiment. We monitored the prey of the preference of the predatory bug on cucumber leaf disks containing: 10 second instar larvae of Thrips tabaci, 10 second or third instar nymphs of Aphis gossypii and 10 adults of Tetranychus urticae for 12 h. in 6 replicates. Number of prey consumed was recorded, the preference indexes of T. tabaci, A. gossypii and T urticae were 0.54, 0.35 and 0.089, respectively. For each experiment, a piece of host plant, determined densities (10-40, 25-25, 40-10) of Aphis gossypii and T. tabaci and one predator were placed in a cage. Each experiment lasted 12h and was repeated six times. Switching behavior of predatory bug was examined. The results of host preference showed that there was no significant difference between the mean number stages of T. tabaci and A. gossypii consumed (p>0.05) and there was significant difference between the mean number of consumed T. tabaci and A. gossypii with T. urticae (p<0.05). In Switching behavior, number of prey consumed was recorded: In the first, with increasing of relative prey density, preference rate was decreased (negative preference), near equal density, decreasing of relative prey density, preference rate was increased (positive preference)
Host preference, switching behavior, Orius niger, Thrips tabaci, Aphis gosssypii, Tetranychus urticae