The Genus Chrysomya (Diptera: Calliphoridae) in the New World1

Four Chrysomya species have recently become established in the Americas and are spreading rapidly. Chrysomya albiceps and C. putoria (=C. chloropyga form putoria) in Peru, C. putoria in Colombia, are reported for the first time. Previously unrecognized specimens of Chrysomya taken in South America in the late 1800's and in 1961 in Puerto Rico are proof of past unsuccessful introductions. Estimated maximum dispersal rates for C. rufifacies (3.2 km/day) and C. albiceps and C. putoria (1.8 km/day), enhanced by their hitchhiking habits and synanthropy, account for their rapid spread in South America. On the eastern slope of the Peruvian Andes, C. putoria occurs mainly below 1000 m, while C. albiceps flourishes from 1000 to 3100 m in areas with an annual median temperature range of 11–23 °C. Data are presented on synanthropy, endophily, and bait preferences for C. putoria and C. albiceps in Peru. Sampling the same Peruvian localities in 1977, 1980, and 1981 has demonstrated that Cochliomyia macellaria is suppressed as populations of C. putoria and C. albiceps increase. At 1000 m, near San Ramón, where C. putoria and C. albiceps are equally numerous, Co. macellaria plummeted in 18 months from 89 to 0.2% of the total blow fly population. At 200 m, near Pto. Bermúdez, where C. albiceps is rare, Co. macellaria suppresssion has been less severe (45.5 to 1 1.3%). Bionomic and other factors favoring displacement of Co. macellaria are discussed.