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

Abstract

The distribution of screwworms, Cochliomyia hominivorax, (Coquerel) was studied in a seasonally moist lowland tropical forest in the Republic of Panama using a combination of field collections and satellite imagery. We found that different forest types could be distinguished and mapped using remotely sensed data. To determine the temporal and spatial distribution of flies, we collected flies coming to rotted liver at 82 sites in ten vegetation types (open areas, edge forest, dry scrub forest, forest successional stage 1, forest successional stage 2, forest successional stage 3, forest successional stage 4, forest successional stage 5, mature forests, palm swamp forest, and forest along streams) over three seasons (dry, transitional, wet). Nine of the vegetation types (excluding dry scrub forest) were identified and mapped using SPOT XS and Landsat 5 TM satellite data. Screwworm flies were most abundant during the transition from wet to dry season. Fly numbers were consistently higher in forest habitats, particularly those with trees 20-30 m in height and a fairly open canopy composed of many deciduous species that shed their leaves during the dry season. Screwworm numbers were also high in palm swamp forest, edge forest, and mature growth forest. Traps sampled in open areas had fewer flies and were unrelated to proximity to cattle. Females accounted for 88% of the total fly counts. This study further substantiates the importance of forests in the ecology and behavior of screwworm flies and demonstrates that remotely sensed data can be used to construct the spatial distribution of these flies in a tropical landscape. We discuss implications of this information to the screwworm eradication program.

Genetic Structure and Demographic History of New World Screwworm Across Its Current Geographic Range

“…The Amazon rain forest represents this putative geographic barrier. Because the screwworm inhabits the interface between savannah and forest borders (Thomas 1993, Phillips et al 2004, Garcia et al 2007, processes involved in this forest fragmentation and recover (Clapperton 1993, Haffer andPrance 2001) might be responsible for the observed geographic structure of screwworm populations.…”

Epidemiological analysis of the New World screwworm (Cochliomyia hominivorax) in Ecuador

“…() found no association between NWS cases and seasonality likely due to a minimal seasonality in climate in their study carried out in Panama; on the contrary, no clearly marked seasonality in the presence of NWS was noted in San Miguel de Los Bancos. Phillips, Welch, and Kramer () reported that flies were most abundant during the transition from wet to dry season. This hypothesis could not be confirmed here because San Miguel de Los Bancos has stable climatic conditions throughout the year.…”

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.…”