Intraguild predation among Scolothrips Iongicornis （Thysanoptera： Thripidae）, Neoseiulus californicus and Typhlodromus bagdasarjani （Acari： Phytoseiidae） under laboratory conditions

This study was carried out on the ability of predatory thrips Scolothrips longi- cornis Priesner to feed on 2 phytoseiid species and vice versa. Also the effect of predation of Neoseiulus californicus （McGregor） on Typhlodromus bagdasarjani Wainstein and Aru- tunjan and vice versa was evaluated. The larvae, prepupae, and pupae of thrips and the eggs, larvae, and protonymphs of phytoseiids were selected as intraguild prey. The in- traguild predation （IGP） among S. longicornis and 2 phytoseiid species was unidirectional and in favor of phytoseiids, i.e., S. longicornis was not able to feed on larval stages of 2 phytoseiids. However, N. californicus and T. bagdasarjani fed on the 1st instar larvae （1.39 and 0.80 per day）, 2nd instar larvae （0.87 and 0.55 per day）, prepupae （0.51 and 0.48 per day）, and pupae of thrips （0.51 and 0.49 per day, respectively）. Both phytoseiids fed on eggs, larvae, and protonymphal stages of each other. Females of N. californicus con- sumed more phytoseiid larvae （2.49 per day） than T. bagdasarjani, which consumed 1.08 N. californicus larvae per day. When Tetranychus urticae was presented as an extraguild prey, intensity oflGP between 2 species ofphytoseiids and on larval stages ofS. longicornis reduced significantly. Therefore, it is concluded that （i） IGP existed among the 3 examined species and lack of feeding of S. longicornis on 2 phytoseiid species can be justified by its feeding type （monophagy）, （ii） N. californicus was much more prone to IGP than was T. bagdasarjani.