Functional response, switching, and prey-stage preference of Scolothrips longicornis (Thysanoptera: Thripidae) on Schizotetranychus smirnovi (Acari: Tetranychidae)

The objective of this study was to evaluate the efficiency of Scolothrips longicornis Priesner (Thysanoptera: Thripidae) as a biocontrol agent of Schizotetranychus smirnovi Wainstein (Acari: Tetranychidae), a key pest of almond trees in the southwest of Iran. To achieve a strategy for the control of this pest, it is important to understand foraging behavior (Functional response, switching, and prey-stage preference) of S. longicornis. The predator exhibited a type III functional response when it was offered S. smirnovi protonymphs at seven densities (2, 4, 8, 16, 32 .64 and 128). Based on the random predator equation, the estimated attack rate (a), handling time (Th), and maximum rate of predation were 0.0048 h−1, 0.4816 h, and 49.84 per day, respectively. Using the Murdoch's model, switching behavior was observed in S. longicornis. The predator switched from one stage when it becomes rare to another more abundant stage. S. longicornis fed on all stages but preferred S. smirnovi larvae and protonymphs. The results of this study revealed that S. longicornis could be used in the integrated management of S. smirnovi. However, further field studies are needed to verify this hypothesis.

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► Functional response of Scolothrips longicornis to different densities of Schizotetranychus smirnovIi was type III.
► Scolothrips longicornis switched from the larvae (less abundant) of prey to the nymphs (more abundant).
► Scolothrips longicornis consumed the larvae and protonymphs of Schizotetranychus smirnovi more than other stages.