T. Maeda et al., Factors affecting the resident time of the predatory mite Phytoseiulus persimilis (Acari : Phytoseiidae) in a prey patch, APPL ENT ZO, 33(4), 1998, pp. 573-576
We studied the effect of Tetranychus urticae-infested plant volatiles on th
e resident time of the predatory mite Phytoseiulus persimilis on a kidney b
ean leaf disc with T. urticae eggs. The leaf was set in a wind tunnel into
which either T. urticae-infested or -uninfested leaf volatiles were introdu
ced. With both volatile flows, the predators showed longer resident time in
discs with prey eggs than in those without eggs. At the same egg density l
evels per disc, the predators stayed longer in uninfested-leaf volatile flo
w than in infested-leaf volatile flow. Chemical analysis showed that the in
fested leaves produced seven terpenoids [(3E)-4,8-dimethyl-1,3,7-nonatriene
, (3E,7E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene, alpha-caryophyllene, b
eta-caryophyllene, alpha-germacrene-D and alpha-farnesene] and methyl salic
ylate. The results suggest that the predators utilize both the prey density
level in a patch they currently inhabit and T. urticae-infested volatiles
from outside the patch for determining whether to remain in or leave the pa
tch.