Violent wave action and the exclusion of Ephydridae (Diptera) from marine temperate intertidal and freshwater beach habitats

Evidence from a study of ephydrids in temperate habitats supports the hypothesis that insects are physically excluded from wave-disrupted marine and freshwater habitats. Marine and freshwater richness values increase with shore elevation and distance from disrupted beach habitats. A comparison of Scandinavian and Nearctic shore-fly communities with the Sorenson index of similarity indicates the resident populations were distinctive species assemblages. Behavioral avoidance, habitat preferences, and shortened developmental cycles presumably reduce immature mortality and exposure to periodic violent inundation.