Changes in the Foraging Behavior, Within-Plant Vertical Distribution, and Microhabitat Selection of a Generalist Insect Predator: an Age Analysis

Abstract

The foraging behavior, within-plant vertical distribution, and microhabitat selection of 2nd instars and adults of Zeius renardii Kolenati were studied in an organic cotton field. In total, 47 individuals (21 nymphs and 26 adults) were observed foraging freely in the field for a total of94 h. Both developmental stages of Z. renardii consumed a wide variety of arthropods including herbivores lmd predators, but predatory insects comprised a greater fraction of the prey of adults compllred with nymphs. Adult Z. renardii also fed on larger prey compared with nymphs. Z. renardii recognized most prey from a distance, and the majority of the prey were moving when they were attacked, suggesting that this predator reacts strongly to visual stimuli. Nymphs and adults also were observed feeding on extrafloral nectaries located on the bottom ofleaves and at the base of fmiting structures, Activity budgets of nymphs and adults were similar, implying no gross changes in their foraging strategies; however, nymphs spent most of their time in the lower plant strata; the adults, in contrast, foraged primmily in the upper canopy. Nymphs also spent more time on the undersurface of leaves and less time on the petioles and stems compared with the adults. These changes in within-plant vertical distribution and microhabitat selection may influence the prey encounter rates and therefore the diet composition of nymphal and adult Z. renardii.

Floral volatiles interfere with plant attraction of parasitoids: ontogeny-dependent infochemical dynamics in Brassica rapa

“…The reduced induction of leaf volatiles seems to indicate that flowering plants “broadcast” less cues to foraging natural enemies (although these cues appear to remain herbivore-specific), and that the reduced attraction of C. glomerata wasps could be generalized to other types of natural enemies. While the ecological relevance of increased attractiveness of B. rapa plants in the pre-flowering stage remains speculative, this result illustrates the highly dynamic nature of the interactions between plants and members of the third trophic level [45, 46]. …”

Omnivore or Herbivore? Field Observations of Foraging byLygus hesperus(Hemiptera: Miridae)

“…They may have been too short or too intrusive to document predation adequately. Although we cannot rule out this possibility, it seems unlikely given our success in quantifying predation and herbivory by other omnivorous predators in cotton, including O. tristicolor, Geocoris spp., Nabis spp., and Z. renardii, by using the same techniques that we used here (Cisneros and Rosenheim 1998;Rosenheim et al 1999;J.A.R. and D. D. Limburg, unpublished data).…”

Behavioral mechanisms underlie an ant-plant mutualism

“…Because the response variables were proportions that summed to one (angulartransformed), one behavior was chosen at random (walking) and excluded from the multivariate analysis (e.g., Cisneros and Rosenheim 1998). For this behavior, a separate univariate test was conducted.…”