On optimal nectar foraging by some tropical bees (Hymenoptera: Apidae) D. W. Roubik, D. Yanega, [A[A[A[A[A[A[A[A[A M. Aluja, S. L. Buchmann and D. W. InouyeApidologie, 26 3 (1995) 197-211DOI: https://doi.org/10.1051/apido:19950303