Plant Resource Use and Pattern of Usage by the Naturalized Orchid Bee (Euglossa dilemma: Hymenoptera: Apidae) in Florida.

Simple Summary: Euglossa dilemma's naturalization in Florida has provided a unique opportunity to study the ecology and biology of an orchid bee distant from its native region. Prior studies have demonstrated its uniqueness as a highly specialized pollinator of invasive plants in Florida. This study documents its use of 259 plant taxa, 237 species and 22 horticultural forms in 156 genera, and 56 families that it uses for pollen, nectar, resins for its nest construction, and fragrance chemicals needed for its courtship. The presence of the bee in a geographic area distant from its native region has resulted in its use of many novel plants, but, like other studied naturalized bees, most of the plants it uses are native, or closely related to native plants in its native region. Because of the bee's very long tongue, ability to vibrate pollen out of specialized flowers, and facility in collecting fragrance and resin rewards from specialized flowers, it uses a higher proportion of these flowers than flowers with easily collected rewards. The ability of E. dilemma to use a large assemblage of plants, including those in most human habitats and natural communities, has facilitated its spread and colonization. Given E. dilemma's abundance and wide occurrence in subtropical Florida and its use of numerous plant species with flowers with both specialized and generalized pollination systems, it has become a common, and at times, an important pollinator. The Neotropical orchid bee Euglossa dilemma was found to be naturalized in southern Florida in 2003, and, by 2022, it had colonized the southern half of Florida. Observations of the bee's collection of plant resources, primarily flowers, were made from 2003 through to 2022 to document its plant usage and understand the patterns of its plant usage. The bee utilized 259 plant taxa, 237 species, and 22 horticultural forms, in 156 genera and 56 families in 263 total uses. Of 247 taxa of flowers, 120 were visited primarily for nectar, 46 for both nectar and pollen, 60 for pollen, including 42 buzz-pollinated flowers, 15 for fragrance chemicals for the males, and 5 for resin rewards by females for nesting. Fragrance chemicals were also collected by males from the leaves of 12 plant species. These extensive resource use data allowed the following predictions to be made. (1) The bee's presence in Florida, distant from its native region of Mexico and Central America and the geographical ranges of other orchid bees, would result the usage of many new taxa of plants. True, half, 74/148 (50%), of the genera and one third, 16/51(31%), of the plant families of the plants with flowers used by the bee were not previously recorded as being utilized by Euglossine bees. (2) Like other naturalized bees, it would use relatively more plants from its native range or congeners of these plants. True, 113/148 (76%) of genera with species bearing collected floral rewards are native or congeners with species native to the bee's native range. (3) Given the bee's long tongue, ability to buzz pollen from poricidal anthers, and ability to collect and use specialized rewards, it would disproportionately use plants with protected or highly specialized floral rewards. True, 180/247 (72%) utilized species bear rewards which were protected and unavailable to, or of no interest to, most other flower visitors. [ABSTRACT FROM AUTHOR]