Nectarivory and Potential Pollination by a Neotropical Marsupial

Abstract

The neotropical marsupial, Caluromys derbianus, the red woolly opossum, is a regular visitor and potential pollinator of Mabea occidentalis (Euphorbiaceae), an understory rainforest tree on Barro Colorado Island, Panama. Caluromys also visits and may pollinate nocturnal nectar-producing flowers of other plants. Nectar is an important food source for the red woolly opossum during seasonal lows in fruit abundance. Pollination by nonflying mammals may commonly occur in tropical forests in light of recent information on tropical tree distribution. The importance of nonflying mammals including rodents, marsupials and primates as pollinators has become more widely accepted recently in light of an increasing number of more critical observations (Rourke & Wiens, 1977; Wiens & Rourke, 1978; Carpenter, 1978; Sussman & Raven, 1978; Lumer, 1980; Janson et al. 1981; Wiens et al., 1979; Hopper, 1980). With the exception of Lumer (1980) and Janson et al. (1981), these studies have focused on Old World systems, geographically limited to the Cape Region of South Africa, Madagascar, and Australia. Australian marsupials have undergone extensive diversification as a result of radiation into a wide range of ecological niches that are filled by placental mammals elsewhere. This diversification includes forms such as the honey possum, Tarsipes, that regularly visit flowers (Hopper, 1980). In the New World, marsupial radiation has been constrained by competition from placental mammals and has been confined to only two families, the Didelphidae and the Caenolestidae. Since little ecological information is available on 1 This study was supported by an Earl C. Anthony graduate fellowship from the University of California, Davis. Drs. Grady L. Webster, Robbin Thorp and Delbert Wiens made helpful comments on the manuscript. Dr. Herbert G. Baker, James Ackerman, Wendy O'Neil and two anonymous reviewers provided valuable suggestions on an earlier draft. I thank the Smithsonian Tropical Research Institute for the use of their facilities, William Glanz for the use of unpublished information and Robert Fischer for providing the weight data for Caluromys derbianus. 2 Botany Department, University of California, Davis, California 95616. ANN. MISSOURI BOT. GARD. 68: 505-513. 1981. 0026-6493/81/0505-051 3/$01 .05/0 This content downloaded from 157.55.39.136 on Thu, 19 May 2016 04:37:47 UTC All use subject to http://about.jstor.org/terms -506 ANNALS OF THE MISSOURI BOTANICAL GARDEN [VOL. 68 the feeding habits of all but the common opossum, Didelphis, it is not surprising that floral visitation and pollination have been considered nonexistent for New World marsupials (L. G. Marshall, in Sussman & Raven, 1978). Although Didelphis virginiana has been reported visiting the flowers of Ceiba pentandra in Mexico (Toledo, 1977) and D. marsupialis in Panama (W. Glanz, pers. comm.), these reports, based on very limited observations in conjunction with other studies, provide little insight into the importance of flower visitation for these opossum