Food-foraging behavior of male euglossini (Hymenoptera: Apidae): vagabonds or trapliners? [Panama]

The nectar-foraging behavior of male euglossine bees (Hymenoptera: Apidae) was studied at a population of Calathea latifolia (Marantaceae) on Barro Colorado Island, Panama, for two weeks. Several marked males of Exuerete smaragdina and Euglossa imperialis foraged at C. latifolia on a daily basis. Immigration rates were low, and the site fidelity of bees was high. Selection of inflorescences by the marked individuals was not random. The bees learned specific locations of inflorescences at which they consistently foraged and ignored nearby inflorescences. However, not all inflorescences in a bee's repertoire were included in each foraging bout. The sequence of inflorescences visited was not the same within or between days nor were the foraging routes uni-directional. Foraging bouts of both male and female bees did not conform to rigid time schedules. Thus, male euglossine bees are not necessarily as transient and vagabond as previously portrayed. Those males that are site-constant forage in a fashion reminiscent of the traplining behavior once described for females. We propose that euglossine bees change their foraging habits as shifts in resource availability and dispersion occur.