Partitioning and Sharing of Pollinators by Four Sympatric Species of Dalechampia (Euphorbiaceae) in Panama

Abstract

Observations were made on distribution, floral morphology, and pollination of 4 spp. of Dalechampia (Euphorbiaceae) in central Panama. The 4 spp. occur sympatrically in various combinations throughout Panama and are pollinated by resin-collecting euglossine bees, and resin- and/or pollen-collecting stingless bees and megachilid bees. With 1 exception, these plant species overlap very little in pollinators or time of pollination. D. heteromorpha is pollinated early in the day by Trigona and Hypanathidium whereas a sympatric congener, D. scandens, is pollinated by the same species of bees late in the day. A 3rd sympatric species, D. dioscoreifolia, is pollinated by euglossine bees. D. heteromorpha also occurs sympatrically with D. tiliifolia; the latter is pollinated by euglossine bees. Individuals of D. dioscoreifolia and D. tiliifolia were observed occurring together at only 1 site where they shared pollinators (euglossine bees) and were receptive to pollination at the same time of day. Interspecific pollen flow was substantial and may have resulted in depressed seedset in D. dioscoreifolia.