The diversity and floral hosts of bees at the Archbold Biological Station, Florida (Hymenoptera: Apoidea)

Mark Deyrup, Jayanthi Edirisinghe, Beth Norden

Abstract


A list is provided of 113 species of bees and their 157 known floral hosts at the Archbold Biological Station(ABS), a 2105 ha site on the Lake Wales Ridge in Highlands County in south-central Florida. This is more species than might be expected at a single site so far south in Florida, based on previous studies in the Miami area and Everglades National Park, but fewer species than would be expected in an upland area of similar size with open habitats in north Florida, the mid-Atlantic states, or the upper Midwest. The small size of the fauna might be correlated with the absence of species that require a cold period in their life cycle, those that require clay or other heavy soils, those that require mesic woodlands and those that require abundant host plants in certain groups that are poorly represented on the ABS, such as Rosaceae. The natural history of southeastern bees is not known in enough detail to ascribe these causes to the individual species that are missing from the ABS fauna. In terms of bee taxa, the relatively small diversity at this site can be mainly attributed to a very poor representation of the genus Andrena (3 species), a poor representation of the genus Lasioglossum (13 species), and a poor representation of the entire family Apidae (22 species). The bee fauna of the ABS is mostly composed of species that occur (or may be expected to occur) through much of the southeastern Coastal Plain, combined with species that are widely distributed in eastern North America. In addition to these elements, there appear to be at least a few species or populations that may be relics of the dry savannahs that stretched across southern North America in parts of the Pleistocene or in the late Pliocene. There is only one species that appears to have come up from tropical Florida or the West Indies. There is no evidence that there are plants that are dependent on single bee species at the ABS, but certain buzz-pollinated plants may rely on only a few species of Bombus. A few species of bees appear to be oligolectic; their host plants, however, are visited by a wide variety of bees and other insects. Bees at the ABS belong to four conspicuous mimetic complexes: metallic green; black with a red abdomen; black with red bands and spots; black with yellow bands and spots. Most ABS bees do not have any warning coloration that is conspicuous to human eyes. There is only one exotic bee on the site, the European honey bee. This lack of a large exotic component in the fauna contrasts with the situation in the ants, of which about one fourth are introduced. Honey bees are often extremely abundant, and possibly dominate nectar and pollen resources in ways that are disruptive to native bees. Although it is easy to observe individual honey bees displacing individual native bees on flowers, there are no data on the ecological effects of honey bees on native pollinators at the ABS. About one quarter ofthe bee species (26) are parasitic species that depend on other species to gather nectar and pollen. This proportion of parasitic species is similar to some other well-studied sites in temperate North America, and is higher than the proportion found in tropical areas.

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