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Keywords
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Foraging behavior, Mutual interference, Predatory coccinellid, Switching behavior, Two-spotted spider mite
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Abstract
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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.
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