Native Solitary Bees Provide Economically Significant Pollination Services to Confection Sunflowers (\u3ci\u3eHelianthus annuus\u3c/i\u3e L.) (Asterales: Asteraceae) Grown Across the Northern Great Plains

The benefits of insect pollination to crop yields depend on genetic and environmental factors including plant selffertility, pollinator visitation rates, and pollinator efficacy. While many crops benefit from insect pollination, such variation in pollinator benefits across both plant cultivars and growing regions is not well documented. In this study, across three states in the northern Great Plains, United States, from 2016 to 2017, we evaluated the pollinatormediated yield increases for 10 varieties of confection sunflowers, Helianthus annuus L. (Asterales: Asteraceae), a plant that is naturally pollinator-dependent but was bred for self-fertility. We additionally measured pollinator visitation rates and compared per-visit seed set across pollinator taxa in order to determine the most efficacious sunflower pollinators. Across all locations and hybrids, insect pollination increased sunflower yields by 45%, which is a regional economic value of over $40 million and a national value of over$56 million. There was, however, some variation in the extent of pollinator benefits across locations and plant genotypes, and such variation was significantly related to pollinator visitation rates, further highlighting the value of pollinators for confection sunflowers. Female Andrena helianthi Robertson (Hymenoptera: Andrenidae) and Melissodes spp. (Hymenoptera: Apidae) were the most common and effective pollinators, while other bees including managed honey bees (Hymenoptera: Halictidae), Apis mellifera L. (Hymenoptera: Apidae), small-bodied sweat bees (Hymenoptera: Halictidae), bumble bees Bombus spp. (Hymenoptera: Apidae), and male bees were either infrequent or less effective on a per-visit basis. Our results illustrate that wild bees, in particular the sunflower specialists A. helianthi and Melissodes spp., provide significant economic benefits to confection sunflower production

CropPol: a dynamic, open and global database on crop pollination

Seventy five percent of the world's food crops benefit from insect pollination. Hence, there has been increased interest in how global change drivers impact this critical ecosystem service. Because standardized data on crop pollination are rarely available, we are limited in our capacity to understand the variation in pollination benefits to crop yield, as well as to anticipate changes in this service, develop predictions, and inform management actions. Here, we present CropPol, a dynamic, open and global database on crop pollination. It contains measurements recorded from 202 crop studies, covering 3,394 field observations, 2,552 yield measurements (i.e. berry weight, number of fruits and kg per hectare, among others), and 47,752 insect records from 48 commercial crops distributed around the globe. CropPol comprises 32 of the 87 leading global crops and commodities that are pollinator dependent. Malus domestica is the most represented crop (32 studies), followed by Brassica napus (22 studies), Vaccinium corymbosum (13 studies), and Citrullus lanatus (12 studies). The most abundant pollinator guilds recorded are honey bees (34.22% counts), bumblebees (19.19%), flies other than Syrphidae and Bombyliidae (13.18%), other wild bees (13.13%), beetles (10.97%), Syrphidae (4.87%), and Bombyliidae (0.05%). Locations comprise 34 countries distributed among Europe (76 studies), Northern America (60), Latin America and the Caribbean (29), Asia (20), Oceania (10), and Africa (7). Sampling spans three decades and is concentrated on 2001-05 (21 studies), 2006-10 (40), 2011-15 (88), and 2016-20 (50). This is the most comprehensive open global data set on measurements of crop flower visitors, crop pollinators and pollination to date, and we encourage researchers to add more datasets to this database in the future. This data set is released for non-commercial use only. Credits should be given to this paper (i.e., proper citation), and the products generated with this database should be shared under the same license terms (CC BY-NC-SA). This article is protected by copyright. All rights reserved

specieslist

List of all collected wild and honey bees identified to specie

Data from: Species richness of wild bees, but not the use of managed honey bees, increases fruit set of a pollinator-dependent crop

1. Native, wild bees are important pollinators for both crop and wild plants. With concerns over the availability and cost of managed honey bees, attention has turned to native, wild bees as crop pollinators. However, the ability of native, wild bees to provide sufficient pollination may depend on their populations at local scales. 2. Therefore, at the farm scale, we examined the pollination contribution of both native, wild bees and managed honey bees to apples, and assessed the relative importance of bee abundance versus species richness. Over three growing seasons, apple fruit set, bee abundance, and bee species richness were measured at orchards in Wisconsin, half of which used managed honey bees, thus allowing us to independently examine the contribution of native, wild bees to fruit set. We additionally conducted observations of honey bees and wild bees foraging on apple blossoms in order to examine functional complementarity. 3. We found that apples are highly dependent on animal pollinators. However, fruit set was not significantly higher at orchards with managed honey bees, nor did it increase with the number of honey bees per orchard. Instead, fruit set significantly increased with the species richness of native, wild bees during bloom. 4. Honey bees and wild bees showed different foraging preferences: honey bees more frequently visited apple flowers on densely blooming trees, while wild bees showed no preference for floral density, thereby evenly visiting trees throughout the orchard. 5. Synthesis and applications. Our results show that native, wild bees play a significant and unique role in apple pollination within our region, and cannot therefore be replaced by managed bees. Moreover, our findings suggest that bee conservation efforts should focus specifically on maintaining or increasing bee species richness in order to improve pollination and crop yields

Native Solitary Bees Provide Economically Significant Pollination Services to Confection Sunflowers (\u3ci\u3eHelianthus annuus\u3c/i\u3e L.) (Asterales: Asteraceae) Grown Across the Northern Great Plains

The benefits of insect pollination to crop yields depend on genetic and environmental factors including plant selffertility, pollinator visitation rates, and pollinator efficacy. While many crops benefit from insect pollination, such variation in pollinator benefits across both plant cultivars and growing regions is not well documented. In this study, across three states in the northern Great Plains, United States, from 2016 to 2017, we evaluated the pollinatormediated yield increases for 10 varieties of confection sunflowers, Helianthus annuus L. (Asterales: Asteraceae), a plant that is naturally pollinator-dependent but was bred for self-fertility. We additionally measured pollinator visitation rates and compared per-visit seed set across pollinator taxa in order to determine the most efficacious sunflower pollinators. Across all locations and hybrids, insect pollination increased sunflower yields by 45%, which is a regional economic value of over $40 million and a national value of over$56 million. There was, however, some variation in the extent of pollinator benefits across locations and plant genotypes, and such variation was significantly related to pollinator visitation rates, further highlighting the value of pollinators for confection sunflowers. Female Andrena helianthi Robertson (Hymenoptera: Andrenidae) and Melissodes spp. (Hymenoptera: Apidae) were the most common and effective pollinators, while other bees including managed honey bees (Hymenoptera: Halictidae), Apis mellifera L. (Hymenoptera: Apidae), small-bodied sweat bees (Hymenoptera: Halictidae), bumble bees Bombus spp. (Hymenoptera: Apidae), and male bees were either infrequent or less effective on a per-visit basis. Our results illustrate that wild bees, in particular the sunflower specialists A. helianthi and Melissodes spp., provide significant economic benefits to confection sunflower production

bee visitation/floral density

Visitation rates of different bees (wild, honey, unique morphospecies) to apple trees of varying floral densit

fruitsetbees

Proportion fruit set, honey bee abundance, wild bee abundance, wild bee species richness and site characteristics at apple orchards in southern Wisconsi

Season of prescribed burns and management of an early successional species affect flower density and pollinator activity in a pine savanna ecosystem

In the age of changing fire regimes, land managers often rely on prescribed burns to promote high diversity of herbaceous plants. Yet, little is known about how the timing of prescribed burns interacts with other ecological factors to maintain biodiversity while restoring fire-adapted ecosystems. We examined how timing of prescribed burns and removal of a dominant, early successional weedy plant yankeeweed (Eupatorium compositifolium) affect flower density and pollinator activity in an early-successional longleaf pine savanna restored from a timber plantation. During the first year of this study, plots received seasonal burn treatments, including unburned control, winter-dry, spring, and summer-wet season burns. During the second year of the study, data on flowers and pollinators were sampled across all plots. In the third year, these seasonal burn treatments were again applied to plots, and data were again collected on flowers and pollinators. In each burn treatment plot, we manipulated the presence of yankeeweed, including one control subplot (no removal) in which yankeeweed was not manipulated and one removal subplot in which yankeeweed was removed, and flowers and pollinators were measured. During the year between burns, flower density was highest in the summer-wet season burn treatment, significantly higher than in the unburned control, while pollinator activity was highest in the summer-wet and spring season burn treatments, significantly higher than the unburned control. During the year in which plots were burned again, flower density was highest in the spring season burn treatment, and pollinators most frequent in both spring and winter-dry season burn treatments, significantly higher than the unburned control. Removing yankeeweed enhanced pollinator activity but only in the year between fire applications. We conclude that prescribed burning enhances floral resource availability and pollinator activity, but the magnitude of these effects depends on when fires are applied. Additionally, removal of yankeeweed can enhance pollinator activity during years between prescribed burns

Do managed bees have negative effects on wild bees?: A systematic review of the literature.

Managed bees are critical for crop pollination worldwide. As the demand for pollinator-dependent crops increases, so does the use of managed bees. Concern has arisen that managed bees may have unintended negative impacts on native wild bees, which are important pollinators in both agricultural and natural ecosystems. The goal of this study was to synthesize the literature documenting the effects of managed honey bees and bumble bees on wild bees in three areas: (1) competition for floral and nesting resources, (2) indirect effects via changes in plant communities, including the spread of exotic plants and decline of native plants, and (3) transmission of pathogens. The majority of reviewed studies reported negative effects of managed bees, but trends differed across topical areas. Of studies examining competition, results were highly variable with 53% reporting negative effects on wild bees, while 28% reported no effects and 19% reported mixed effects (varying with the bee species or variables examined). Equal numbers of studies examining plant communities reported positive (36%) and negative (36%) effects, with the remainder reporting no or mixed effects. Finally, the majority of studies on pathogen transmission (70%) reported potential negative effects of managed bees on wild bees. However, most studies across all topical areas documented the potential for impact (e.g. reporting the occurrence of competition or pathogens), but did not measure direct effects on wild bee fitness, abundance, or diversity. Furthermore, we found that results varied depending on whether managed bees were in their native or non-native range; managed bees within their native range had lesser competitive effects, but potentially greater effects on wild bees via pathogen transmission. We conclude that while this field has expanded considerably in recent decades, additional research measuring direct, long-term, and population-level effects of managed bees is needed to understand their potential impact on wild bees

Studies published from 1900–2016 examining the potential effect of managed bees on wild bees through changes in plant communities, including the spread of exotic plants.

<p>For all studies, we recorded the species of managed and wild bees, and indicated whether managed bees were native or exotic to the study region, the location (continent and country) and context of the study including field (natural, semi-natural, developed, agricultural, or experimental plot), lab, or greenhouse, and all variables measured, including the managed bee metric (independent variable), plant metric (dependent variable), and any explanatory or mechanistic variables. The overall effect of managed bees on plant communities, as reported by the study, is also recorded and noted as positive (+), neutral (0), negative (-), or mixed.</p