DISTRIBUTION OF FLYING INSECTS IN RELATION TO PREDACIOUS WEB-SPINNINGLARVAE OF NEODITOMYIA-FARRI (DIPTERA, MYCETOPHILIDAE) IN A JAMAICAN CAVE

Larvae of predacious Neoditomyia farri Coher (Mycetophilidae: Keroplat inae) in Dromilly Cave in Trelawny, Jamaica, were restricted to the ch amber where flying insects were most abundant. Here they occupied over hangs within 2 m of the floor. The distribution of Eying insects was d etermined using adhesive traps. Total mean numbers throughout the cave varied between 953.0 and 10.5 insects per square meter of trap surfac e per hour. Scatopsidae predominated (up to 96%) where there were deep deposits of fresh bat guano and numerous roosting bats. Pholeomyia (M ilichiidae) (0-2.4%) were similarly distributed but Phoridae (4-63%) w ere more evenly distributed throughout the cave. Minor components comp rised Sciaridae (1%) followed by Scelionidae, Staphylinidae, Streblida e, Tineidae, Formicidae, and Mycetophilidae (all <0.2%). Numbers of Ey ing insects decreased logarithmically with increasing height. In areas of high insect abundance, fewer insects flew near the walls than in t he center of the chamber. Estimates of numbers of insects caught in N. farri webs indicated that food availability more than any other facto r determines the distribution of these larvae.