Assessment of trends in predation pressure on insects across temperate forest microhabitats
Experimental tests of whether predation pressure on insects is sometimes restricted to particular forest microhabitats have been carried out only in one or two vegetation periods and described
for only a few predators. In the present study, we describe the seasonal dynamics of a wide spectrum of insect predators among forest microhabitats. We also examine the impact of weather conditions on insect predation, and predict that forest openness would
influence the predation trends among forest microhabitats. The design of our experiments enabled direct measurement of relative predation pressure on bait (larvae of the blowfly Calliphora vicina) pinned onto selected microhabitats (the base, trunk and
leaves of trees) within a temperate floodplain forest (Czech Republic). The most parsimonious generalized additive model showed significant trends in the predation rate among the forest microhabitats. The highest predation rate for bait was at the base of trees
and the lowest predation rate was on leaves. We also observed significant differences in the species structure of predators in various microhabitats. The most common source of predation on trunks was from birds, whereas wasps were the most common predator on
leaves and ants were the most common at the base of trees.