TIME AND RESOURCE PARTITIONING IN STETHORUS-PUNCTUM (COLEOPTERA, COCCINELLIDAE)

Stethorus punctum (LeConte) is an obligate predator of tetranychid mites. Laboratory studies examined the proportion of time beetles spent searching, feeding, and resting when adult females and third instars encountered an abundance of all instars of the tetranychid mite Tetranychus urticae Koch. Preference for various prey instars, relative handling times, and the influence of starvation on these behaviors were determined. Satiated female beetles spent 45.1% of their time searching, 14.4% feeding, and 40.5% resting. Female beetles that were starved spent a greater proportion of time feeding, with an increase in handling time per prey. The increase in handling time was due to a more complete extraction of body fluids from individual prey. Female beetles preferred mite eggs, and that preference was not significantly altered by starvation. Satiated larvae spent 78.4% of their time searching and 21.6% feeding; they did not spend any measurable amount of time resting. Starvation of larvae significantly increased the percentage of time spent feeding and the handling time per prey. Third instars preferred nymphal mite stages to other instars, and this preference was not significantly altered by starvation. The results are discussed in reference to predator-prey dynamics.