Floral Visitation and Pollen Collection by Native Bees in Temperate Deciduous Forests with Diverse Understory Communities

Sep 16, 2026

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Native bees associated with deciduous forests are likely central to pre-colonial bee fauna in the eastern United States, yet data on their floral resource use has been insufficient for guiding management. This study characterizes floral visitation and pollen collection by bees in mature deciduous forests managed by the National Park Service across ~550 km of latitude in Indiana and Michigan. Records from 4194 specimens across 103 species, plus pollen data from 665 specimens, show genus-specific differences in pollen use and emphasize canopy trees and shrubs as key resources.

LanguageEnglish

CategoryGeneral

FormatPDF

Pages63

Reading Time22 min

AccessFree to download

Abstract

Study Implications

Introduction

Floral resource use in forest contexts

Deciduous forest habitat and seasonal bee activity

Research gap and management relevance

Journal of Forestry [https://doi.org/10.1007/s44392-025-00032-1](https://doi.org/10.1007/s44392-025-00032-1) ORIGINAL PAPER Floral Visitation and Pollen Collection by Native Bees inTemperate Deciduous Forests with Diverse Understory Communities Lucia R. Weinman1,2,3 · Katherine J. Turo3 · Trent Ress3 · Rachael Winfree3 Received: 7 October 2024 / Accepted: 21 April 2025 © The Author(s) 2025 Abstract The native bees associated with deciduous forest are likely the pre-colonial dominant bee fauna of the eastern United States, yet we lack the data on their resource use needed to guide management. We characterized bees’ floral resource use in mature deciduous forests managed by the National Park Service at sites spanning ~ 550 km of latitude in Indiana and Michigan. We collected floral visitation records for 4194 bee specimens representing 103 species, and data on bees’ pollen collection for 665 specimens. Our findings highlight differences among dominant bee genera in their floral resource use, especially pollen, and confirm the importance of canopy tree species and shrubs for bees in deciduous forests, even in those with diverse understory floral assemblages. As the largest, most spatially extensive source of data on bees’ use of floral resources within mature deciduous forests in North America, these records provide a useful reference point for forest bee conservation. Keywords Temperate broadleaf forest · Wild bees · Floral resources · Pollen analysis · Canopy ecology · Understory plant diversity Study Implications Forests are considered important bee habitat, but little data exist on bees’ use of forest plant species, including deciduous trees and shrubs. Across three National Parks in the upper Midwest, we found that bees in mature deciduous forests predominantly collected pollen from native spring understory herbs, willows, and maple trees, but bee genera varied greatly in their pollen use. This diversity of foraging behavior suggests that forestry practices that encourage flowering plant diversity are also likely to enhance forest bee communities. Likewise, because we found that canopy and shrub flowers were common pollen resources, even in a mature, ecologically intact deciduous forest, our findings suggest that we should explicitly consider flowering trees and shrubs in future assessments of forests’ value for pollinators. Extended author information available on the last page of the article Introduction Forests are increasingly recognized as critical habitat for native bee species globally (Ulyshen et al. 2023), yet bee communities in forests have been relatively understudied. In the United States and Canada, for example, entomological research in deciduous and coniferous forests has focused on insect pests and detritivores (Ayres and Lombardero 2000 ; Ramsfield et al. 2016), while bee ecology and conservation research has predominantly occurred in agricultural and other open, meadow-type natural and anthropogenic habitats (Winfree 2010 ; Ulyshenet al. 2023) . Thus, as the consensus grows that forests provide important habitat for native bees, and land managers are increasingly called upon to consider how their forest management affects bee species, many aspects of forest bee ecology remain underexplored (Ulyshen et al. 2023) . One aspect of bee ecology that is especially important but is still understudied in most forest contexts, is bees’ use of floral resources (Menz et al. 2011 ; Winfree 2010) . Bees obtain all of their food from flowers in the form of pollen and nectar, and bee populations are generally thought to be limited by the availability of floral resources (Roulston and Goodell 2011 ; Goulson et al. 2015) . Plants can vary in their attractiveness to bees, though, and bee taxa often differ in their floral preferences, the flexibility of their diet, and the richness of resources they require (Cane and Sipes 2006 ; Minckley and Roulston 2006 ; reviewed in Danforth et al. 2019) . Additio

FAQs

What was the focus of this study on native bees?

The study examined how native bees use floral resources in mature temperate deciduous forests, emphasizing floral visitation and pollen collection.

Where were the data collected and what was the geographic scope?

Data were collected in mature deciduous forests managed by the National Park Service across sites spanning about 550 km of latitude in Indiana and Michigan in the eastern United States.

What did the findings suggest about which plant resources matter most?

Results highlighted the importance of canopy tree species and shrubs for bees, even when understory communities are diverse, and showed strong differences among bee genera in pollen use.

Sep 16, 2026

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