Non-Native Non-Apis Bees Are More Abundant on Non-Native Versus Native Flowering Woody Landscape Plants

Abstract

Urban ecosystems can support diverse communities of wild native bees. Because bloom times are conserved by geographic origin, incorporating some non-invasive non-native plants in urban landscapes can extend the flowering season and help support bees and other pollinators during periods when floral resources from native plants are limiting. A caveat, though, is the possibility that non-native plants might disproportionately host non-native, potentially invasive bee species. We tested that hypothesis by identifying all non-native bees among 11,275 total bees previously collected from 45 species of flowering woody landscape plants across 213 urban sites. Honey bees, Apis mellifera L., accounted for 22% of the total bees and 88.6% of the non-native bees in the collections. Six other non-native bee species, accounting for 2.86% of the total, were found on 16 non-native and 11 native woody plant species. Non-Apis non-native bees in total, and Osmia taurus Smith and Megachile sculpturalis (Smith), the two most abundant species, were significantly more abundant on non-native versus native plants. Planting of favored non-native hosts could potentially facilitate establishment and spread of non-Apis non-native bees in urban areas. Our host records may be useful for tracking those bees’ distribution in their introduced geographical ranges.

Osmia taurus (Hymenoptera: Megachilidae): A Non-native Bee Species With Invasiveness Potential in North America

“…In its native range, O. taurus has been classified as a polylectic species with a preference for pollen from the Juglandaceae, Rosaceae, and Fabaceae families, which is similar but broader than the pollen preferences of O. cornifrons that prefers pollen from the Rosaceae and Fabaceae families (Maeta 1978, Haider et al 2014, Vaudo et al 2020). In North America, O. taurus has been observed visiting Cercis canadensis , the eastern redbud (Fabales: Fabaceae), and several species in the genus Prunus (Rosales: Rosaceae) (Potter and Mach 2022). However, O. taurus seems to collect pollen primarily from non-native shrubs species of the genera Aesculus (Sapindales: Sapindaceae), Viburnum (Dipsacales: Adoxaceae), and Ilex (Aquifoliales: Aquifoliaceae) (Potter and Mach 2022).…”

“…In North America, O. taurus has been observed visiting Cercis canadensis , the eastern redbud (Fabales: Fabaceae), and several species in the genus Prunus (Rosales: Rosaceae) (Potter and Mach 2022). However, O. taurus seems to collect pollen primarily from non-native shrubs species of the genera Aesculus (Sapindales: Sapindaceae), Viburnum (Dipsacales: Adoxaceae), and Ilex (Aquifoliales: Aquifoliaceae) (Potter and Mach 2022). This pattern of preference for non-native plants has also been reported for O. cornifrons (Vaudo et al 2020).…”

“…Additional evidence indicates that O. taurus may have adverse effects on the environment through the facilitation of other non-native species. Seemingly, O. taurus has been reported pollinating non-native plant species in North America suggesting a possible indirect negative effect on native plants that can be the preferred floral hosts of native Osmia bees (Potter and Mach 2022). However, future studies should investigate to what extent native and non-native Osmia share the same native and non-native floral resources in different habitats (e.g., Vaudo et al 2020).…”

Pollinator cultivar choice: An assessment of season-long pollinator visitation among coreopsis, aster, and salvia cultivars

“…Regionally appropriate plant lists of trees, shrubs and flowers that attract and support pollinators are good resources to consult for landscape design or renovation (e.g., Harris et al, 2016;Braman et al, 2017;Braman and Quick, 2018;Mach and Potter, 2018;Smitley et al, 2019). Non-native, non-Apis bees were determined to be significantly more abundant visitors to nonnative vs. native plants, especially Osmia taurus Smith and Megachile sculpturalis (Smith) (Potter and Mach, 2022). Those offers suggested that planting of favored non-native hosts could have the unintended consequence of facilitating the spread of non-native, non-Apis bees in urban areas.…”

Whole community invasions and the integration of novel ecosystems

“…Invasive species can dramatically impact native communities [ 44 , 45 ], and the extent of invasion can vary significantly [ 46 , 47 ]. Invasion in this context is especially relevant with regard to disturbance [ 48 ] and the formation of novel ecosystems [ 47 ]; the common origin of non-native species can influence their behavior in a new community [ 49 ].…”