TRICHOMYCETE FUNGI LIVING IN THE GUTS OF COSTA-RICAN PHYTOTELM LARVAEAND OTHER LENTIC DIPTERANS

Species of Harpellales (Trichomycetes: Zygomycotina) were found living in the guts of Chironomidae, Culicidae and Ceratopogonidae larvae inh abiting reservoirs of water retained by the leaves of epiphytic bromel iads and a few other plants, including pineapple and banana, as well a s from a swamp. Periodic collections in Costa Rica between 1984 and 19 91 included a low wet forest (La Selva Biological Station), a cloud fo rest (Monteverde Cloud Forest Reserve), and a zone of premontane rain forest (Las Cruces Biological Station). A new trichomycete, Smittium p hytotelmatum, that inhabits bloodworms (Chironomidae) was found primar ily but not exclusively in bromeliads, and several axenic cultures of the fungus were obtained. A second, rarer, new species from a bromelia d bloodworm, S. fasciculatum, is also described, as is the new species Stachylina paludosa from swamp bloodworms. Two possibly hew but unnam ed species of Smittium are described from lentic dipteran larvae. Mosq uito, midge and ceratopogonid larvae were hosts to a geographically wi despread Harpellales, Smittium culisetae. Bracts of Heliconia inflores cences, though often populated by mosquito larvae and other insects, c ontained no larvae with gut fungi. Water in Heliconia bracts averaged 2.36 pH units above that in bromeliads (average pH 5.02). It was demon strated in the laboratory that Heliconia-inhabiting mosquito larvae ma intained in their native water could be artificially infested with axe nic cultures of S. culisetae. The apparent lack of natural fungal infe station of mosquito larvae in heliconias may be due to the ephemeral n ature of the plants' water-holding bracts and extrinsic factors such a s recruitment of fungal inoculum.