Mohammadali Mirhosseini

The Stethorus gilvifrons Mulsant (Coleoptera: Coccinellidae) is an effective biological control agent of the two spotted spider mite (TSSM), Tetranychus urticae Koch (Acari: Tetranychidae), which is a serious pest of different crops over the world. To start a successful biological control program, study of different aspects of foraging behavior of natural enemies is inevitable. The study aimed to investigate the switching behavior and mutual interference of adult female of S. gilvifrons on TSSM. The five different rates of nymph and adult stages of TSSM (10:30, 15:25, 20:20, 25:15 and 30:10 nymph:adult) were used to evaluate of predator switching behavior; five densities of predator (1, 2, 4, 8 and 16) were exposed to 320 TSSM nymphs for mutual interference study. The results of switching experiment indicated that S. gilvifrons prefer the most abundant prey stage for eating. There was a negative significant relationship (P < 0.01 and R2 = 0.93) between predator density and per capita preys eaten as it was decreased from 108.6 to 18.1 when predator density increased from 1 to 16. The per capita searching efficiency was also significantly affected by predator density (P < 0.05) as it decreased from 0.416 to 0.161 as predator densities increased from 1 to 16. The results revealed the high predation potential of this acarophagous ladybird on different stage of TSSM and it can be used as an important biological control agent for this destructive pest.