Functional response of Anystis baccarum (Acari: Anystidae) preying on two raspberry pests: Aphis idaei (Hemiptera: Aphididae) and Neotetranychus rubi (Acari: Tetranychidae)

Abstract Raspberry is an increasingly economically important soft fruit worldwide. To adopt the approaching EU Green Deal, growers are required to seek alternative pest management strategies. The predatory mite, Anystis baccarum (L.), which was recently discovered in raspberry, could be a promising candidate. However, the biology and predation capacity of this species in raspberry are unknown. This study aimed to investigate the functional response of A. baccarum to two common raspberry pests, Aphis idaei van der Goot and Neotetranychus rubi Trägårdh. In controlled laboratory conditions, six densities of A. idaei nymphs (2, 4, 8, 12, 16, and 24) and adult N. rubi females (2, 4, 8, 16, 24, and 32) were introduced in separate functional response experiments. Furthermore, the prey preference of A. baccarum on the two species was investigated when 5 A. idaei nymphs and adult N. rubi females were offered simultaneously to the predator. Anystis baccarum exhibited type II functional response to both prey, with capture rate for A. idaei higher than N. rubi. In addition, A. idaei was more likely to be consumed by A. baccarum than N. rubi. While promising as a biocontrol agent, the searching behavior, cannibalistic nature, and long generation time of A. baccarum suggest that it should not be relied upon solely for pest management in raspberry. Further studies on synergistic interactions with other biocontrol agents are recommended.