ABSTRACT
Eurema daira , a small pierid butterfly, frequents open habitats, including pasture, savanna, and strand, from northern Argentina northward through South America, Central America, the Antilles, and the southeastern United States. The work was carried out at Hacienda La Pacifica, 50 meters elevation, 5km NW Canas, Guanacaste Province, Costa Rica. The habitat consists of a mosaic of orchards, pasture, second growth, as well as deciduous and riparian forests. The focus of the local Eurema daira populations was in regularly grazed pastures where its larval host plant, Aeschynomene americana, occurred. Emigration is important in E. daira. At the onset of the dry season in Guanacaste, many individuals, particularly wet season morphs and among those especially females, emigrate up-slope. These emigrations may take individuals 40–50 km and as much as 2,000 m higher in elevation, and produces reproductive populations or resting aggregations of E. daira in localities where the species is absent in the wet season.
