Prey-preference of Orius albidipennis (Het.: Anthocoridae) on onion thrips and two-spotted spider mite under laboratory conditions

Prey-preference of the predatory bug, Orius albidipennis Reuter, with predation rate and prey-preference tests on the basis of completely randomized design (CRD) and without the replacement of consumed prey was examined under laboratory conditions (25 ± 1°C, 65 ± 5% RH and L16: D8 photoperiod). Results of the predation rate test indicated that the predation of the female predatory bug on the 2nd larvae of onion thrips and the female two-spotted spider mite was 14.8 ± 1.46 and 20 ± 0.7 respectively, showing a significant difference (P < 0.05) between them. In the prey-preference test, the preying of the female predatory bug on the 2nd larvae of onion thrips and the female two-spotted spider mite was 8.4 ± 0.84 and 4.4 ± 0.22 respectively. The Manly preferance index (α) of the 2nd larvae of onion thrips (prey I) and the female two-spotted spider mite (prey II) was 0.8 ± 0.09 and 0.2 ± 0.03 respectively, which demonstrated that the predatory bug more preferred the 2nd larvae of onion thrips than the two-spotted spider mite. Both tests were repeated for the male predatory bug in similar conditions. In the predation rate test, the results from the preying of the male predatory bug on the 2nd larvae of onion thrips and the female two-spotted spider mite was 11 ± 1.58 and 12 ± 1.22 respectively, showing no significant difference. In the prey-preference test, consumption of the male predatory bug from the 2nd larvae of onion thrips was 3.3 ± 0.13 and from the female two-spotted spider mite was 3.2 ± 0.17. In this experiment, the Manly preference index (α) of the 2nd larvae of onion thrips (prey I) and the female two-spotted spider mite (prey II) was 0.52 ± 0.03 and 0.48 ± 0.05 respectively. According to these data, the male predatory bug showed no preference for either prey species.