Evaluation of Costa Rican copepods (Crustacea : Eudecapoda) for larval Aedes aegypti control with special reference to Mesocyclops thermocyclopoides

This study attempted to find organisms for the biological control of the mo squito Aedes aegypti in Costa Rica. Copepods of the genera Arctodiaptomus, Eucylops, Mesocyclops, Megacyclops, and Thermocyclops were collected in sev eral parts of the country and cultured for laboratory evaluations. Mesocycl ops thermocyclopoides was the most successful species in reducing the numbe r of larval Ae, aegypti (7.3 larvae in 24 h at a density of 200 Aedes/liter ). Arctodiaptomus dorsalis, Eucyclops cf, bondi, Eucyclops leptacanthus, Me gacyclops sp., and Thermacyclops decipens were not effective predators. In cage simulation trials, M, thermocyclopoides showed 100% larval reduction a fter I wk and adult mosquitoes disappeared after 7 wk. The copepod was able to survive in Aechmea sp. bromeliads under laboratory conditions. In field trials under 3 different climatic conditions M, thermocyclopoides survived 2-5 months in bromeliad led evils and 3-6 months in used car tires. In tir es, this species reduced the number of larval Ae. aegypti 79, 90, and 99% i n tropical dry, moderate, and humid climates, respectively. An El Nino phen omenon affected the results by drought, which apparently also caused a decl ine in the population of the predatory mosquito Toxorhynchites haemorrhoial is superbus. Considering these severe test conditions, M thermocyclopoides might be a promising predator for mosquito control in Costa Rica.