Studies have found that natural enemies are generally more abundant and herbivores less abundant in diverse habitats compared to simple ones. However, few studies have examined the mechanisms underlying the greater abundance of natural enemies in diverse habitats. It has been implicated that outbreaks of herbivores are prevented in diverse habitats because they provide more favorable microhabitats, refuges, and alternative food sources, such as pollen and nectar and a diverse array of alternate prey, for natural enemies. The greater stability in food availability for generalist predators and parasitoids may maintain their greater abundance in diverse habitats. Feeding and foraging behaviors of many natural enemies are closely linked to flowering plants and prey availability, and may influence natural enemy foraging patterns. Identifying factors that encourage the recruitment and establishment of generalist enemies in natural and managed systems should lead to more successful conservation biological control efforts and the creation of sustainable systems.
These studies examine the relationship between plant species diversity, floral resource availability, and habitat type, and the abundance and diversity of herbivore and natural enemy taxa on native woody shrubs. Eleven native, flowering woody shrub species were surveyed in open field, wood edge, and wooded habitats at both natural and managed arboretum locations. The overall objective was to identify plant species that are attractive to natural enemies (beneficial insectary plants) and the mechanisms leading to this attraction. This survey identified plant species associated with an assemblage of generalist natural enemies whose abundance positively correlated to prey abundance and floral resource availability. A greater understanding of these factors will help us to design managed urban and agricultural systems that favor natural enemies and reduce the likelihood of pest outbreaks and therefore reduce the need for pesticides.
Species 1: Hymenoptera
Species 2: Araneae
Keywords: Ornamentals, Vegetational diversity
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA