Large Roads Disrupt Insect Movement: A Case Study of the Spodoptera littoralis (Lepidoptera: Noctuidae)

Roads are a growing mosaic in the landscape, splitting and reducing the area of natural habitats of organisms. To examine the effects of large roads on insect movements, the Egyptian cotton leaf worm moth Spodoptera littoralis was used as a model species in a mark-recapture experiment. The flight of male moths towards female sexual pheromone across a motorway and an open field was compared. Road constructions may disrupt movements of individual insects as recapture probability was lower when moths had to cross a road to reach the bait compared with that in undisturbed natural habitat. The observed road effect may appear a very general response among insects as noctuids are generally highly mobile. We conclude that increasing fragmentation of natural habitats due to road networks may not only affect many insect populations worldwide, but also deteriorate ecosystem function and services as insects are important pollinators of natural and cultivated plants.