Metabarcoding of honey to assess differences in plant-pollinator interactions between urban and non-urban sites

Abstract

Ever-faster rates of urbanization have led to the substantial loss of agricultural land and natural areas. Furthermore, vegetated land is often fragmented and dominated by nonnative plant species within urban areas, which is likely to impact plant-pollinator interactions. However, the study of plant-pollinator interactions is labor intensive and remains challenging. Here, we compared plant species visited by honeybees in urban versus non-urban sites, using metabarcoding to identify pollen in honey samples. We identified a total of 262 plant genera, 15 of which were represented predominantly. Samples varied greatly in terms of plant composition, the number of nonnative genera and the number of crop plant genera. Even though land cover differed between urban and non-urban sites, plant diversity in the honey did not. We discuss our results in the light of challenges associated with the spatial scale of bee activity, preference behavior in flower visitation, and statistical power.

Application of plant metabarcoding to identify diverse honeybee pollen forage along an urban–agricultural gradient

“…This result is congruent with Lucek et al. (2019) which found that honey samples from more urban sites in Switzerland tended to have higher floral diversity, though this difference was not found to be significant. However, we caution that the site‐level replication of our study is not sufficient to draw firm conclusions about the relationship between urban and agricultural land use and honeybee forage dynamics in the Midwest.…”

“…The question of how honeybee foraging behaviour responds to the unique challenges of urban and agricultural landscapes is salient from both basic and applied perspectives (Couvillon et al., 2014a; Härtel & Steffan‐Dewenter, 2014). With respect to urban land use, recent empirical studies have described honeybee (Lau et al., 2019; Lucek et al., 2019) diet and foraging distance (Garbuzov et al., 2015). The only study, however, to articulate a theoretical relationship between honeybee foraging behaviour and suburban land use is that of Waddington et al.…”

Honey bee pollen foraging ecology across an urbanization gradient

“…The question of how honey bee foraging behavior responds to the unique challenges of urban and agricultural landscapes is salient from both basic and applied perspectives (Couvillon et al 2014a, Härtel andSteffan-Dewenter 2014). With respect to urban land use, recent empirical studies have described honey bee (Lau et al 2019, Lucek et al 2019) diet and foraging distance (Garbuzov et al 2015). The only study, however, to articulate a theoretical relationship between honey bee foraging behavior and suburban land use is that of Waddington et al (1994), where the authors suggest that the fine-grain pattern of floral patch distribution typical of suburban landscapes favors independent patch discovery over the use of waggle dance recruitment by foraging honey bees.…”

Harnessing the power of metabarcoding in the ecological interpretation of plant-pollinator DNA data: strategies and consequences of reads filtering

“…Among these, four datasets were obtained by processing pollen found in nests or carried on insects bodies (Bell et al, 2017; Biella et al, 2019; Vaudo et al, 2020; along with the unpublished one, hereafter Tommasi et al, unpublished, that contains information about interactions between 249 insects and 156 plants). Three dataset comes from honey sample analysis (Lucek et al 2019; DeVere et al, 2017; Jones et al, 2021), and one was obtained from the analysis of pollen mock samples specially constructed for methodological assessments (Bell et al, 2019).…”