FURTHER OBSERVATIONS ON THE EMERGENCE COMPOSITION AND PHENOLOGY OF CRANE FLIES (DIPTERA, TIPULIDAE) FROM A TROPICAL RAIN-FOREST STREAM AT EL-VERDE, PUERTO-RICO

This paper represents a continued study of the emergence of phenology of adult crane flies from a small stream in northeastern Puerto Rico. Twenty-two species were collected by an emergence trap from February 1 991 through April 1992 at Quebrada Prieta, a second-order stream in th e Luquillo Mountains. Four species of Limonia comprised 53% of the ind ividuals and one species alone, Limonia (Geranomyia) virescens (Loew) comprised 22%. These additional fifteen months of emergence data confi rm the pronounced seasonality in the crane fly emergence phenology rep orted by Gelhaus et al. (1993), with most emergence occurring during N ovember through April, and little or no emergence from June through Se ptember. Decline in the individuals of the dominant species, L. viresc ens, and in numbers of total Tipulidae overall, may be related to the canopy re-growth following the destruction by Hurricane Hugo in 1989, and the resulting decline in light levels and benthic algal levels. Gr azers on benthic algae included 48% of the crane fly individuals.