D. pusillus pupates on lower leaves, in leaf litter, or in other protected locations, often in groups.

Both larvae and adults are active predators that can consume numerous eggs or nymphs each day.

Adults and larvae feed by piercing the insect with their mouthparts and alternately sucking and regurgitating the internal contents to digest and consume it.

They are strong fliers that will migrate to areas that contain high densities of whiteflies.

Since adult female beetles must feed on over 200 eggs per day in order to reproduce, it may be of limited benefit in greenhouses where whitefly populations are low.