Influence of Habitat, Season, and Attractant on Adult Behavior of the Screwworm (Diptera: Calliphoridae) in a Tropical Dry Zone in Costa Rica

Abstract

Influence of attractant, season, habitat, temperature, and physiological state of the screwworm, Cochliomyia hominivorax (Coquerel), on daily activity and oviposition were examined during a 122 d study in a tropical dry forest in Costa Rica. Flies were marked and released. Numbers of flies visiting baits increased during the wet season and decreased during the dry season; 3 times more flies were observed at baits during the wet season than were observed during the dry season. An average of 33 females and 3 males was observed per day during the study. More flies (3.6 times) were attracted to liver than to sentinel sheep; many flies originally marked at liver failed to return and few of them oviposited on sentinel sheep. Females marked at sheep were recaptured more times and remained in the study area longer. More females marked at sheep sites were recaptured (51.4-54.1%) than those marked at liver sites (32.3-44.7). More than 6 times as many flies were observed at forest than at pasture sites. The physiological state of the female influenced daily activity. High temperatures during midday (> 31 degrees C) depressed activity and decreased the number of foraging hours available for flies during the dry season. Decreasing host resources and number of hours available for foraging may be factors that limit screwworm populations in the dry season.

Seasonal and Spatial Distributions of Adult Screwworms (Diptera: Calliphoridae) in the Panama Canal Area, Republic of Panama

“…We sampled in an Acacia Plantation and successional forest still with banana plants and fruit trees that were also not distinguished on the imagery. We collected in areas we deÞned as edge forests and forest along streams based on the importance of these habitats for high ßy activity in previous studies from Costa Rica, Mexico, and Texas (Hightower and Alley 1963, Brenner 1985, Parker et al 1993. For the study in Costa Rica, edges were deÞned as the ecotone between croplands and forest and their within-forest category were sites at least 100 m inside the tree line (Parker et al 1993).…”

“…They had more ßies visit liver traps than sentinel animals or sworm-lure-baited wind oriented traps. The procedures and maintenance of the liver-baited trap sites we used followed those established by Parker et al (1993). Once a trap site was established, we resampled at the same location for an average of 5Ð 6 d. We had three technicians available, so typically we sampled in three different vegetation types on the same day.…”

“…In tropical environments, however, screwworm populations exist year around at higher densities with rainfall (Krafsur et.al. 1979, Parker et al 1993) and habitat Thomas 1989, Parker et al 1993) the principal factors affecting their distribution and activity. When comparing tropical scrub forest, dry tropical forests, and nonforested areas, the areas of highest screwworm activity are in forests and ecotones Parker et al 1993).…”

“…1979, Parker et al 1993) and habitat Thomas 1989, Parker et al 1993) the principal factors affecting their distribution and activity. When comparing tropical scrub forest, dry tropical forests, and nonforested areas, the areas of highest screwworm activity are in forests and ecotones Parker et al 1993). These authors, however, made no distinction between the types and varying sizes of forest habitats and other vegetation that create a patchwork on the tropical landscape.…”

Spatial analysis of targeted surveillance for screw‐worm fly (Chrysomya bezziana or Cochliomyia hominivorax) in Australia

“…6,7,12,[14][15][16][17][18] The likelihood of establishment was calculated by combining these three maps multiplicatively to identify areas with suitable conditions for pupal development and adult fly survival.…”