Insect dispersal is affected by the wind and as a result, influenced by the presence of windbreaks. Wind reductions, microclimate modifications and vegetative diversity, influence insect distribution in sheltered areas.
Wingless insects and very small insects generally depend on air currents to carry them to new sites, but they tend to settle in areas with low windspeeds. It is often more advantageous for a flying insect to remain within its boundary layer where windspeeds are lower than the insect's flight speed. Flying insects tend to accumulate in areas of reduced windspeed where they have greater control of flight; however, distribution patterns can be modified by directed movements in response to olfactory and visual stimuli. Many insect species are attracted to food and shelter within windbreaks.
Windbreaks can concentrate insects in particular areas. Insects accumulate leeward of windbreaks as compared with unsheltered sites. The pattern of distribution may be affected by windspeed, angle of incidence of the wind, permeability of the windbreak, turbulence, source of insects (windbreak, local fields, upwind sites), insect behavior, insect species and vegetative composition. Windbreak vegetation may serve as a source of insect pests and their natural enemies and infestation levels in adjacent fields will be affected by their relative abundance. Knowledge of these distribution patterns should be considered when designing pest-management control strategies.
Available at: http://works.bepress.com/judith_pasek/4/