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Cuckoo bumblebees (Bombus subgenus Psithyrus) are social parasites that have lost the ability to establish their own nests, and instead usurp the nest of a bumblebee host to reproduce. Accordingly, they are entirely dependent upon a host species to complete their life cycle, and are therefore vulnerable to co–extinction. Despite this, the current consensus is that there remains much we do not know about the fundamental ecology of many cuckoo bumblebee species, which is crucial for conservation.To investigate data gaps for cuckoo bumblebees, we conducted a systematic review to quantify the peer‐reviewed literature that has been produced, including which species have been most studied and which disciplines have been explored.Over half of all Psithyrus species were represented in fewer than 10 publications each, including 2 species listed as Critically Endangered by the IUCN.Research on cuckoo bumblebees is heavily weighted towards Europe and European species, while Asian species were under‐represented.Key research areas such as ecology and behaviour have received little attention for the majority of cuckoo bumblebees, which may hamper conservation effortsOur results quantitatively support observations made in other publications on the scarcity of data on cuckoo bumblebees, and highlight the need for further research on many species for whom fundamental knowledge is missing—particularly in light of the vulnerability of this subgenus to extinction. [ABSTRACT FROM AUTHOR]

The main component of chocolate, cocoa (Theobroma cacao), is a significant commercial agricultural plant that directly sustains the livelihoods of an estimated forty to fifty million people. The economies of many cocoa producing nations, particularly those in the developing world, are supported by cocoa export revenue. To ensure satisfactory yields, however, the plant is usually intensely treated with pesticides because it is vulnerable to disease and pest attacks. Even though pesticides help protect the cocoa plant, unintended environmental contamination is also likely. Honey, produced from nectar obtained by honeybees from flowers while foraging, can serve as a good indicator for the level of pesticide residues and environmental pesticide build-up in landscapes. Here, we use a systematic literature review to quantify the extent of research on residues of pesticides used in cocoa cultivation in honey. In 81% of the 104 studies examined for this analysis, 169 distinct compounds were detected. Imidacloprid was the most frequently detected pesticide, making neonicotinoids the most frequently found class of pesticides overall. However, in cocoa producing countries, organophosphates, organochlorines, and pyrethroids were the most frequently detected pesticides. Interestingly, only 19% of studies were carried out in cocoa producing countries. We recommend prioritizing more research in the countries that produce cocoa to help to understand the potential impact of pesticide residues linked with cocoa cultivation in honey and the environment more generally to inform better pesticide usage, human health, and environmental policies. [ABSTRACT FROM AUTHOR]

Forest products derived from woody trees, such as fruits, seeds, honey, wood and others, are important resources for supporting rural livelihoods. However, little is known about the breeding systems or floral visitors of trees that provide these resources, often due to the difficulty of accessing tree canopies. This study addresses key knowledge gaps from a data poor region, providing information on the breeding systems and contribution of biotic pollination to two trees abundant in south-central Africa, that provide forest product supports for rural livelihoods: Julbernardia paniculata (Benth.) Troupin and Syzygium guineense (Willd.) subsp. barotsense F. White (Fabaceae and Myrtaceae respectively). The breeding systems of these species were assessed by conducting controlled pollination experiments, and then measuring the effects on reproductive success to determine the degree of self-compatibility and pollen limitation. Floral visitors and their behaviour were observed to provide preliminary information on possible pollinator groups. S. guineense appeared to be self-compatible, while J. paniculata showed signs of both self-incompatibility and pollen limitation. Floral visitors of both species were dominated by bees, with native honeybees (Apis mellifera) providing the highest visitation rates. These insights provide the first steps for understanding the reproductive ecology of these key tree species and can help to inform sustained management and conservation aimed at protecting forests and supporting rural livelihoods, as well as broaden the understanding of the floral visitors, and contribution of biotic pollination to forest tree reproductive success. [ABSTRACT FROM AUTHOR]

Pesticides help produce food for humanity's growing population, yet they have negative impacts on the environment. Limiting these impacts, while maintaining food supply, is a crucial challenge for modern agriculture. Mitigation measures are actions taken by pesticide users, which modify the risk of the application to nontarget organisms, such as bees. Through these, the impacts of pesticides can be reduced, with minimal impacts on the efficacy of the pesticide. Here we collate the scientific evidence behind mitigation measures designed to reduce pesticide impacts on bees using a systematic review methodology. We included all publications which tested the effects of any pesticide mitigation measure (using a very loose definition) on bees, at any scale (from individual through to population level), so long as they presented evidence on the efficacy of the measure. We found 34 publications with direct evidence on the topic, covering a range of available mitigation measures. No currently used mitigation measures were thoroughly tested, and some entirely lacked empirical support, showing a weak evidence base for current recommendations and policy. We found mitigation measure research predominantly focuses on managed bees, potentially failing to protect wild bees. We also found that label-recommended mitigation measures, which are the mitigation measures most often applied, specifically are seldom tested empirically. Ultimately, we recommend that more, and stronger, scientific evidence is required to justify existing mitigation measures to help reduce the impacts of pesticides on bees while maintaining crop protection. [ABSTRACT FROM AUTHOR]

Bees are essential pollinators of crops and wild plants and their ability to forage and pollinate are key aspects of their behaviour. Bee populations are under threat, with the use of insecticides a contributing factor. Most research has focused on neonicotinoid insecticides and bee mortality, and little is known about impacts on bee foraging and delivery of pollination services. However, other insecticide classes, such as organophosphates and pyrethroids, are increasingly used globally, but little is known about how these widely used substances may impact bees, particularly non‐honeybees.We exposed bumblebee Bombus terrestris colonies to field‐relevant doses of a pyrethroid (lambda‐cyhalothrin) and an organophosphate (dimethoate) and investigated sublethal effects on behaviour at the individual and colony level, in addition to pollination service delivery under semi‐field conditions.We show, for the first time, that exposure to these chemicals impacts the activity and pollen provisioning of bumblebee Bombus terrestris audax colonies, while no short‐term effects on flower handling behaviour or pollination service delivery were detected.We found that colonies exposed to dimethoate were less active, with 67% fewer bees leaving the colony to forage than control colonies, and of those that returned, 92% fewer returned pollen provisions to the nest. Colonies exposed to lambda‐cyhalothrin did not differ in activity; however, 62% fewer of these bees returned with pollen provisions.Policy implications. These findings give important insights into how exposure to different classes of insecticides could impact bumblebee activity and their provision of pollen required for colony development. With a focus on neonicotinoids in terms of policy changes regarding insecticides and bees, we show that other insecticide classes should also be re‐examined in relation to their potential risks for pollinators. We confirm the need to improve risk assessment of insecticides to assess sublethal effects, include non‐honeybee species in risk assessment processes and also consider key behaviours such as foraging and interactions with plants. [ABSTRACT FROM AUTHOR]

Quantifying the contributions of insect pollinators to crops provides insight into how pollination services should be managed and protected into the future.Faba bean, Vicia faba var minor (Linneaus), is a widely grown crop globally that can benefit from pollinator visitation, but only from species that are morphologically compatible with the plant's long‐corollae flowers. Here, we rank insect pollinators in terms of their potential importance to faba bean pollination and quantify the economic value of pollination for Irish faba beans.Our findings demonstrate that bee pollination contributes significantly to the pod set of faba beans, and, consequently, the crop's production value. We find that pollination services account for almost half of Ireland's total faba bean market value, with the pollinator contribution estimated at almost €4,000,000 per year.We estimate that, relative to other pollinators, wild bumblebees contribute to approximately 70% of the economic value of pollination services in faba bean fields, driven mainly by the contributions of a long‐tongued bumblebee species, Bombus hortorum (Linneaus; Hymenoptera: Apidae).Based on these results, we suggest that B. hortorum populations be encouraged on farmland through appropriate management to ensure the continued delivery of pollination services to Irish faba beans. [ABSTRACT FROM AUTHOR]

Insect pollination, and in particular pollination by bees, is a highly valued ecosystem service that ensures plant reproduction and the production of high-quality crops. Bee activity is known to be influenced by the weather, and as the global climate continues to change, the flying frequency and foraging behaviour of bees may also change. To maximise the benefits of pollination in a changing world, we must first understand how current weather conditions influence the activity of different bee species. This is of particular interest in a country such as Ireland where inclement weather conditions are nominally sub-optimal for foraging. We observed honeybee (Apis mellifera) and buff-tailed bumblebee (Bombus terrestris) activity across a variety of weather conditions at seven apple orchards to determine how four weather variables (temperature, relative humidity, solar radiation, wind) influenced the flight activity of each species. Each orchard contained three honeybee and three bumblebee colonies, and so we were able to observe a colony of each species concurrently in the same weather conditions. Overall, honeybees were more sensitive to changes in weather than bumblebees and could be more predisposed to future changes in within-day weather conditions. Our results indicate bumblebees could compensate for low honeybee activity in inclement conditions, which supports the theory that pollinator diversity provides resilience. This may be particularly important in management of pollinators in crops that flower in the spring when weather is more variable, and to allow varied responses to global climate change. [ABSTRACT FROM AUTHOR]

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Beneficial insects provide valuable services upon which we rely, including pollination. Pollinator conservation is a global priority, and a significant concern in Ireland, where over half of extant bee species have declined significantly in recent decades. As flower‐visiting insects rely on flowering plants, one way to conserve and promote pollinator populations is to protect high‐quality habitat. We analyzed the structure of insect–flower interactions from multiple habitat categories in a large database of interactions from Ireland. Our primary goals were to compare spatial and temporal variation in Irish network structures, compare Irish networks to published networks from other countries, and provide evidence‐based recommendations for pollinator conservation in Ireland by identifying well‐visited plant species that may promote high pollinator diversity, abundance, and functional complementarity. Habitat types within Ireland differed substantially: seminatural grasslands had the highest pollinator species richness and largest number of unique pollinator species, while intensively managed habitats exhibited negative asymmetry (more plant than pollinator species). This negative asymmetry is notable because most plant–pollinator networks exhibit a positive asymmetry. Within intensively managed habitats, agricultural and urban habitats differed. Urban habitats had the highest number of non‐native plant species while agricultural habitats had the lowest pollinator species richness. We also found Irish networks varied across the growing season, where July had the highest plant and insect species richness. When comparing Irish networks to published networks from other countries, we found Irish networks had a higher ratio of plant species to pollinator species, and that this difference was most evident in agricultural habitats. This ratio means the typical network asymmetry (more pollinator than plant species) was flipped (more plant than pollinator species) in the Irish network. We conclude that conserving seminatural grasslands in Ireland will be an essential component of pollinator conservation and identify thirty‐five plant species important for restoring seminatural habitats. [ABSTRACT FROM AUTHOR]

Herbicides are the most widely used pesticides globally. Although used to control weeds, they may also pose a risk to bee health. A key knowledge gap is how bees could be exposed to herbicides in the environment, including whether they may forage on treated plants before they die. We used a choice test to determine if bumblebees would forage on plants treated with glyphosate at two time periods after treatment. We also determined whether glyphosate and its degradation product aminomethylphosphonic acid were present as residues in the pollen collected by the bees while foraging. Finally, we explored if floral resources (nectar and pollen) remained present in plants after herbicide treatment. In general bees indiscriminately foraged on both plants treated with glyphosate and controls, showing no avoidance of treated plants. Although the time spent on individual flowers was slightly lower on glyphosate treated plants, this did not affect the bees' choice overall. We found that floral resources remained present in plants for at least 5 days after lethal treatment with glyphosate and that glyphosate residues were present in pollen for at least 70 h posttreatment. Our results suggest that bees could be exposed to herbicide in the environment, both topically and orally, by foraging on plants in the period between herbicide treatment and death. Identifying this route of exposure is a first step in understanding the risks of herbicides to bees. The effects of herbicides on bees themselves are uncertain and warrant further investigation to allow full risk assessment of these compounds to pollinating insects. Environ Toxicol Chem 2022;41:2603–2612. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. [ABSTRACT FROM AUTHOR]

Besides the benefits of plant protection products (PPPs) for agricultural production, there is an increasing acknowledgement of the associated potential environmental risks. Here, we examine the feasibility of summarizing the extent of PPP usage at the country level, using Ireland as a case study, as well as at the European level. We used the area over which PPPs are applied (basic area) as an example variable that is relevant to initially assess the geographic extent of environmental risk. In Irish agricultural systems, which are primarily grass-based, herbicides fluroxypyr and glyphosate are the most widely applied active substances (ASs) in terms of basic area, followed by the fungicides chlorothalonil and prothioconazole that are closely associated with arable crops. Although all EU countries are subject to Regulation (EC) No 1185/2009, which sets the obligation of PPP usage data reporting at the national level, we only found usable data that met our criteria for Estonia, Germany, Finland, and Spain (4 of 30 countries reviewed). Overall, the most widely applied fungicide and herbicide in terms of basic area were prothioconazole (20%, 7% and 5% of national cultivated areas of Germany, Estonia and Ireland) and glyphosate (11%, 8% and 5% of national cultivated areas of Spain, Estonia and Ireland) respectively, although evaluations using application frequency may result in the observation of different trends. Several recommendations are proposed to tackle current data gaps and deficiencies in accessibility and usability of pesticide usage data across the EU in order to better inform environmental risk assessment and promote evidence-based policymaking. [ABSTRACT FROM AUTHOR]

1. Managing farmland to benefit biodiversity is becoming increasingly necessary to combat biodiversity declines and maintain ecosystem services. Results-based agri-environmental schemes are a tool used to achieve this by paying farmers based on environmental results delivered. These schemes often utilise plant indicator species to assess results at field scale; however, it is unknown if focusing on enhancing a subset of one biodiversity group within results-based schemes impacts wider biodiversity, and whether local-scale implementation of results-based schemes or/and the wider landscape are more important drivers of biodiversity patterns. 2. Insect pollinators provide important pollination services for many crop and wild plants, and as mobile organisms often experience landscape at large spatial scales. We tested whether insect pollinators are affected at local scale by a results-based scheme scored based on plant indicators, or if landscape management is more important, and whether there were different responses between taxon-specific groups. Bumblebees, solitary bees, hoverflies and butterflies were sampled using transects and pan traps in 23 fields with varying scores assigned by the scheme, situated in high-intensity (≥65% improved grassland) or low-intensity (≥65% seminatural grassland) landscapes. 3. Results indicate taxon-specific responses to local and landscape management in semi-natural grasslands. Bumblebees responded positively to local-scale management in fields with higher floral diversity, whereas hoverflies and butterflies responded positively to low-intensity landscape management. 4. Synthesis and applications. Using plant species as indicators for biodiversity in agri-environment schemes can have indirect benefits for non-target taxa like bumblebees, but broader indicators should be developed to incorporate other pollinator groups. Pollinator groups respond differently to local and landscape management in semi-natural grasslands. Agri-environmental management should consider a range of different management measures and landscape scale approaches where possible, to maximise benefits for a range of pollinator taxa. [ABSTRACT FROM AUTHOR]

Bumblebees are a key pollinator group globally which have declined over time. However, while some species remain common others are rare and have declined at a sharper rate. The Great Yellow Bumblebee (Bombus distinguendus Morawitz) is classified as 'Endangered' on the Irish Red List, and 'Vulnerable' at European level. We aimed to investigate the ecology of B. distinguendus within the wider bumblebee community in its only remaining Irish population to inform conservation management. Eight true bumblebee species were recorded in total in four habitat types surveyed, with highest species richness in species-rich grassland and highest abundance in urban habitats. Highest numbers of B. distinguendus were found in two designated nature reserves. However, outside these reserves the species was only found in three of twelve sites surveyed in both species-rich and coastal grassland habitats. B. distinguendus is a late emerging species in this region with a foraging preference for Common Knapweed (Centaurea nigra). Availability of key forage species was lowest when numbers of B. distinguendus were highest, potentially limiting survival of this species. Some smaller suitable habitats in urban areas and roadside verges were not used by the species, which suggests potential issues with habitat connectivity, patch size and/or availability of nesting and hibernation sites. Implications for insect conservation: Based on our findings, we suggest that existing species-rich and coastal grassland sites should be conserved, and other areas restored, for B. distinguendus in Ireland. Conservation management should focus on delaying cutting grasslands until late September, winter grazing of stock and reducing pesticides and fertilisers with the aim of increasing forage availability in late season, and ensuring that suitable habitats are connected in the landscape to allow adequate habitat area as well as movement and dispersal of the species to new areas. [ABSTRACT FROM AUTHOR]

Western honeybees (Apis mellifera L.), native to Europe and Africa, have been transported worldwide and are now one of the most important global crop pollinator species. Although the relative contribution of honeybees to global crop pollination is increasingly recognized, relatively little is known about their importance as pollinators in wild plant communities. The only remaining wild and unmanaged western honeybee populations are in Africa. We investigated the importance of honeybees as pollinators of diverse wild plant communities in two protected areas within the Maputaland-Pondoland-Albany biodiversity hotspot in South Africa. Sites were far from any known areas of beekeeping, and so all honeybees were most likely from wild colonies. Honeybees visited a large proportion of flowering plant species within these two communities (40% and 35%) and also provided a substantial proportion of visits to the plants they visited (40% and 32%, respectively). However, when pollinator importance indices (based on abundance and the size and purity of pollen loads) were calculated for a small subset of plants, honeybees were only important pollinators of 29% of the plants they visited. Our data provide a first step in determining the importance of honeybees as flower visitors and pollinators in wild plant communities and the potential impacts of honeybee declines on these highly diverse grassland ecosystems. Our work suggests that many plants in the grassland systems studied are visited by non-Apis flower visitors and therefore that conservation efforts should also focus on these pollinator groups. [ABSTRACT FROM AUTHOR]

Bees and the pollination services they deliver are beneficial to both food crop production, and for reproduction of many wild plant species. Bee decline has stimulated widespread interest in assessing hazards and risks to bees from the environment in which they live. While there is increasing knowledge on how the use of broad-spectrum insecticides in agricultural systems may impact bees, little is known about effects of other pesticides (or plant protection products; PPPs) such as herbicides and fungicides, which are used more widely than insecticides at a global scale. We adopted a systematic approach to review existing research on the potential impacts of fungicides and herbicides on bees, with the aim of identifying research approaches and determining knowledge gaps. While acknowledging that herbicide use can affect forage availability for bees, this review focussed on the potential impacts these compounds could have directly on bees themselves. We found that most studies have been carried out in Europe and the USA, and investigated effects on honeybees. Furthermore, certain effects, such as those on mortality, are well represented in the literature in comparison to others, such as sub-lethal effects. More studies have been carried out in the lab than in the field, and the impacts of oral exposure to herbicides and fungicides have been investigated more frequently than contact exposure. We suggest a number of areas for further research to improve the knowledge base on potential effects. This will allow better assessment of risks to bees from herbicides and fungicides, which is important to inform future management decisions around the sustainable use of PPPs. [ABSTRACT FROM AUTHOR]

Honeybees are integral in socio-ecological landscapes with 1.6 million tonnes of honey produced globally, of which ~518,000 are traded (IPBES, [11]). Despite some information on beekeeping impacts, little is known about wild-harvest honey hunting impacts (collecting honey from feral hives) on the conservation status of honeybees and their woodland habitats. Of the nesting trees, 20 trees (95.2% of nesting trees, 4.7% of all surveyed trees) were poached in the mopane compared to eight (100% of nesting trees, 1.9% of all surveyed trees) in the miombo. This study suggests that limited damage is inflicted on woodlands by honey hunters: only 4.7% of mature trees in the mopane had evidence of honey hunting activity with only 0.7% of all trees felled completely. [Extracted from the article]

Proboscis length has been proposed as a key dimension of plant pollination niches, but this niche space has not previously been explored at regional and global scales for any pollination system. Hawkmoths are ideal organisms for exploring pollinator niches as they are important pollinators in most of the biodiverse regions of the earth and vary greatly in proboscis length, with some species having the longest proboscides of all insects., Using data sets for nine biogeographical regions spanning the Old and New World, we ask whether it is possible to identify distinct hawkmoth pollination niches based on the frequency distribution of proboscis length, and whether these niches are reflected in the depths of flowers that are pollinated by hawkmoths. We also investigate the levels of specialization in hawkmoth pollination systems at the regional and community level using data from interaction network studies., We found that most regional hawkmoth assemblages have bimodal or multimodal distributions of proboscis length and that these are matched by similar distributions of floral tube lengths. Hawkmoths, particularly those with longer proboscides, are polyphagous and at the network level show foraging specialization equivalent to or less than that of bees and hummingbirds. In the case of plants, shorter-tubed flowers are usually visited by numerous hawkmoth species, while those that are longer-tubed tend to exclude shorter-proboscid hawkmoths and thus become ecologically specialized on longer-proboscid hawkmoth species. Longer-tubed flowers tend to have greater nectar rewards, and this promotes short-term constancy by long-proboscid hawkmoths., Our results show that pollinator proboscis length is a key niche axis for plants and can account for the patterns of evolution in functional traits such as floral tube length and nectar volume. We also highlight a paradoxical trend for nectar resource niche breadth to increase according to proboscis length of pollinators, while pollinator niche breadth decreases according to the tube length of flowers., A is available for this article. [ABSTRACT FROM AUTHOR]

The ability to forage and return home is essential to the success of bees as both foragers and pollinators. Pesticide exposure may cause behavioural changes that interfere with these processes, with consequences for colony persistence and delivery of pollination services., We investigated the impact of chronic exposure (5-43 days) to field-realistic levels of a neonicotinoid insecticide (2·4 ppb thiamethoxam) on foraging ability, homing success and colony size using radio frequency identification ( RFID) technology in free-flying bumblebee colonies., Individual foragers from pesticide-exposed colonies carried out longer foraging bouts than untreated controls (68 vs. 55 min). Pesticide-exposed bees also brought back pollen less frequently than controls indicating reduced foraging performance., A higher proportion of bees from pesticide-exposed colonies returned when released 1 km from their nests; this is potentially related to increased orientation experience during longer foraging bouts. We measured no impact of pesticide exposure on homing ability for bees released from 2 km, or when data were analysed overall., Despite a trend for control colonies to produce more new workers earlier, we found no overall impacts of pesticide exposure on whole colony size., Synthesis and applications. This study shows that field-realistic neonicotinoid exposure can have impacts on both foraging ability and homing success of bumblebees, with implications for the success of bumblebee colonies in agricultural landscapes and their ability to deliver crucial pollination services. Pesticide risk assessments should include bee species other than honeybees and assess a range of behaviours to elucidate the impact of sublethal effects. This has relevance for reviews of neonicotinoid risk assessment and usage policy world-wide. [ABSTRACT FROM AUTHOR]

Insect pollinators are essential for both the production of a large proportion of world crops and the health of natural ecosystems. As important pollinators, bumblebees must learn to forage on flowers to feed both themselves and provision their colonies., Increased use of pesticides has caused concern over sublethal effects on bees, such as impacts on reproduction or learning ability. However, little is known about how sublethal exposure to field-realistic levels of pesticide might affect the ability of bees to visit and manipulate flowers., We observed the behaviour of individual bumblebees from colonies chronically exposed to a neonicotinoid pesticide (10 ppb thiamethoxam) or control solutions foraging for the first time on an array of morphologically complex wildflowers ( Lotus corniculatus and Trifolium repens) in an outdoor flight arena., We found that more bees released from pesticide-treated colonies became foragers, and that they visited more L. corniculatus flowers than controls. Interestingly, bees exposed to pesticide collected pollen more often than controls, but control bees learnt to handle flowers efficiently after fewer learning visits than bees exposed to pesticide. There were also different initial floral preferences of our treatment groups; control bees visited a higher proportion of T. repens flowers, and bees exposed to pesticide were more likely to choose L. corniculatus on their first visit., Our results suggest that the foraging behaviour of bumblebees on real flowers can be altered by sublethal exposure to field-realistic levels of pesticide. This has implications for the foraging success and persistence of bumblebee colonies, but perhaps more importantly for the interactions between wild plants and flower-visiting insects and ability of bees to deliver the crucial pollination services to plants necessary for ecosystem functioning. [ABSTRACT FROM AUTHOR]

The recent growth in bioenergy crop cultivation, stimulated by the need to implement measures to reduce net CO2 emissions, is driving major land-use changes with consequences for biodiversity and ecosystem service provision. Although the type of bioenergy crop and its associated management is likely to affect biodiversity at the local (field) scale, landscape context and its interaction with crop type may also influence biodiversity on farms. In this study, we assessed the impact of replacing conventional agricultural crops with two model bioenergy crops (either oilseed rape Brassica napus or Miscanthus × giganteus) on vascular plant, bumblebee, solitary bee, hoverfly and carabid beetle richness, diversity and abundance in 50 sites in Ireland. We assessed whether within-field biodiversity was also related to surrounding landscape structure. We found that local- and landscape-scale variables correlated with biodiversity in these agricultural landscapes. Overall, the differences between the bioenergy crops and the conventional crops on farmland biodiversity were mostly positive (e.g. higher vascular plant richness in Miscanthus planted on former conventional tillage, higher solitary bee abundance and richness in Miscanthus and oilseed rape compared with conventional crops) or neutral (e.g. no differences between crop types for hoverflies and bumblebees). We showed that these crop type effects were independent of (i.e. no interactions with) the surrounding landscape composition and configuration. However, surrounding landscape context did relate to biodiversity in these farms, negatively for carabid beetles and positively for hoverflies. Although we conclude that the bioenergy crops compared favourably with conventional crops in terms of biodiversity of the taxa studied at the field scale, the effects of large-scale planting in these landscapes could result in very different impacts. Maintaining ecosystem functioning and the delivery of ecosystem services will require a greater understanding of impacts at the landscape scale to ensure the sustainable development of climate change mitigation measures. [ABSTRACT FROM AUTHOR]

Pollinating insects are not only important in wild plant pollination, but also in the production of a large number of crops. Oilseed rape production is increasing globally due to demands for biofuels which may have impacts on pollinating insects which visit the crop and on the pollination services delivered to co-flowering wild plants. In this study, we tested (1) the degree of pollinator sharing between oilseed rape and native wild plants in field margins and hedgerows and (2) the effects of oilseed rape on the quality of pollination service delivered to these wild plants. We found large overlap between flower visitors of wild plants and oilseed rape, but the composition of species overlap differed with respect to each wild plant species. Nearly all individual visitors caught on both the crop and foraging on wild species carried crop pollen, but more than half the insects also carried pollen from wild plants. However, very little oilseed rape pollen was deposited on wild plant stigmas. This shows that (1) oilseed rape overlaps in pollinator niche with most co-flowering wild plants, and (2) crop pollen deposition on wild plant stigmas is low which may indicate that it is unlikely to cause reductions in seed set of wild plants, although this was not measured here. Furthermore, wild plants in field margins and hedgerows are important sources of alternative forage for pollinating insects even when a crop is mass flowering, and we suggest maintenance and augmentation of field margins and hedgerows to provide alternative forage for pollinator conservation to continue provision of pollination services to both crops and wild plants. [ABSTRACT FROM AUTHOR]

Pollinators are beneficial for many wild and crop plants. As a mass-flowering crop, oilseed rape has received much focus in terms of its pollination requirements but despite a threefold increase in area of cultivation of this crop in Ireland over the past 5 years, little is known about its pollination here. We surveyed the flower visiting insects found in commercial winter oilseed rape fields and evaluated the importance of different pollinator groups, investigated the contribution of insect pollination to oilseed rape seed production, and estimated the economic value of insect pollination to the crop at a national level. Our data showed that winter oilseed rape is visited by a wide variety of insect species, including the honeybee, bumblebees, solitary bees, and hoverflies. The honeybee, Eristalis hoverflies and bumblebees (especially Bombus sensu stricto and B. lapidarius) were the best pollinators of winter oilseed rape based on the number of pollen grains they carry, visitation rates per flower and their relative abundance per field. Exclusion of pollinators resulted in a 27 % decrease in the number of seeds produced, and a 30 % decrease in seed weight per pod in winter crops, with comparable values from a spring oilseed rape field also. The economic value of insect pollination to winter oilseed rape was estimated as €2.6 million per annum, while the contribution to spring oilseed rape was €1.3 million, resulting in an overall value of €3.9 million per annum. We can suggest the appropriate conservation and management of both honeybees and wild pollinators in agricultural areas to ensure continued provision of pollination services to oilseed rape, as a decrease in insect numbers has the potential to negatively influence crop yields. [ABSTRACT FROM AUTHOR]

The Bombus sensu stricto species complex is a widespread group of cryptic bumblebee species which are important pollinators of many crops and wild plants. These cryptic species have, until now, largely been grouped together in ecological studies, and so little is known about their individual colony densities, foraging ranges or habitat requirements, which can be influenced by land use at a landscape scale. We used mass-flowering oilseed rape fields as locations to sample bees of this complex, as well as the second most common visitor to oilseed rape B. lapidarius, and molecular RFLP methods to distinguish between the cryptic species. We then used microsatellite genotyping to identify sisters and estimate colony densities, and related both proportions of cryptic species and their colony densities to the composition of the landscape surrounding the fields. We found B. lucorum was the most common member of the complex present in oilseed rape followed by B. terrestris. B. cryptarum was also present in all but one site, with higher proportions found in the east of the study area. High numbers of bumblebee colonies were estimated to be using oilseed rape fields as a forage resource, with B. terrestris colony numbers higher than previous estimates from non-mass-flowering fields. We also found that the cryptic species responded differently to surrounding landscape composition: both relative proportions of B. cryptarum in samples and colony densities of B. lucorum were negatively associated with the amount of arable land in the landscape, while proportions and colony densities of other species did not respond to landscape variables at the scale measured. This suggests that the cryptic species have different ecological requirements (which may be scale-dependent) and that oilseed rape can be an important forage resource for many colonies of bumblebees. Given this, we recommend sustainable management of this crop to benefit bumblebees. [ABSTRACT FROM AUTHOR]

Global declines in pollinating insects have been linked with agricultural intensification and land-use change. Increased production of novel crops for bioenergy is causing changes in agricultural practice, but the effects on different pollinating taxa have not yet been quantified. However, the major pollinating groups (social bees, solitary bees, hoverflies and butterflies) are likely to respond differently to changes in land use and shifts in crop cultivation patterns., We assessed the impacts of two bioenergy crops, oilseed rape Brassica napus L. and Miscanthus Miscanthus X giganteus on (i) the diversity and abundance of four taxonomic groups of pollinating insects, (ii) insect community composition, (iii) floral resources and (iv) nesting sites for bumblebees, by comparing bioenergy crops with conventional arable and grass crops in a large network of commercial fields., We found that although there were more bumblebees in oilseed rape fields, conventional crops and bioenergy crops did not differ greatly in species richness of most pollinator groups, although more floral resources were found in the bioenergy crops. However, solitary bees were more abundant and species rich in energy crops than conventional wheat, and more trap-nesting bees and wasps were found in Miscanthus than oilseed rape. In addition, novel assemblages of solitary bees were found in the bioenergy crops., All pollinator groups, and flowering plants, were more abundant in field margins than in the centre of crop fields. Although there were no differences among crop types, nest-searching bumblebees were confined to field margins. This highlights the importance of field margins as forage and nesting habitat for pollinators in farmland., Synthesis and applications. Differential responses to field-scale growth of bioenergy crops were displayed by the taxonomic groups studied, suggesting that effects on biodiversity cannot be generalized from studies based on a small suite of taxonomic groups and must include a range of taxa for overarching results. To optimize habitat for pollinators in agricultural areas, our data suggest that a diversity of crop types at small scales may have positive impacts and supports appropriate management and conservation of field margins and hedgerows during conversion to bioenergy production. [ABSTRACT FROM AUTHOR]

One major characteristic of invasive alien species is their occurrence at high abundances in their new habitat. Flowering invasive plant species that are visited by native insects and overlap with native plant species in their pollinators may facilitate or disrupt native flower visitation and fertilisation by forming large, dense populations with high numbers of flowers and copious rewards. We investigated the direction of such a proposed effect for the alien invasive Rhododendron ponticum in Irish habitats. Flower visitation, conspecific and alien pollen deposition, fruit and seed set were measured in a self-compatible native focal plant, Digitalis purpurea, and compared between field sites that contained different relative abundances of R. ponticum. Flower visitation was significantly lower at higher alien relative plant abundances than at lower abundances or in the absence of the alien. Native flowers experienced a significant decrease in conspecific pollen deposition with increasing alien abundance. Heterospecific pollen transfer was very low in all field sites but increased significantly with increasing relative R. ponticum abundance. However, lower flower visitation and lower conspecific pollen transfer did not alter reproductive success of D. purpurea. Our study shows that indirect interactions between alien and native plants for pollination can be modified by population characteristics (such as relative abundance) in a similar way as interactions among native plant species. In D. purpurea, only certain aspects of pollination and reproduction were affected by high alien abundances which is probably a result of high resilience due to a self-compatible breeding system. Native species that are more susceptible to pollen limitation are more likely to experience fitness disadvantages in habitats with high relative alien plant abundances. [ABSTRACT FROM AUTHOR]

Exposure to agricultural pesticides is often cited as one of the primary drivers of pollinator decline. Most of the research has been focused on the impacts of insecticides but herbicides have been receiving more attention for their potential implications for bee health. However, little is known about how pollinators are being exposed to herbicides, whether it is through direct contact with herbicides during spraying, foraging on herbicide-treated plants or contact with herbicide residues within the wider environment. We examined the interactions between bumble bees (Bombus terrestris) and herbicide-treated plants, comparing behavior of bees when offered a choice between glyphosate-treated and untreated plants. We aimed to determine whether bees avoid herbicide-treated plants, thus reducing their potential exposure to herbicides. Individual foragers were released into an exclusion cage containing four Phacelia tanacetifolia plants: two sprayed with glyphosate and two untreated plants. We measured the frequency and duration of nectar feeding, pollen collecting and investigation (inspection but not foraging) of plants. We tested interactions between the bumble bees and plants which had been freshly sprayed (within 24 hours) and again once the glyphosate had begun to translocate within the plant – but before any significant physical effects began to appear (48 hours). Here, we present the preliminary results from this study. [ABSTRACT FROM AUTHOR]

Bumblebees are exposed to pesticides applied for crop protection while foraging on treated plants, with increasing evidence suggesting that this sublethal exposure has implications for pollinator declines. The challenges of navigating and learning to manipulate many different flowers underline the critical role learning plays for the foraging success and survival of bees. We assessed the impacts of both acute and chronic exposure to field-realistic levels of a widely applied neonicotinoid insecticide, thiamethoxam, on bumblebee odour learning and memory. Although bees exposed to acute doses showed conditioned responses less frequently than controls, we found no difference in the number of individuals able to learn at field-realistic exposure levels. However, following chronic pesticide exposure, bees exposed to field-realistic levels learnt more slowly and their short-term memory was significantly impaired following exposure to 2.4 ppb pesticide. These results indicate that field-realistic pesticide exposure can have appreciable impacts on learning and memory, with potential implications for essential individual behaviour and colony fitness. [ABSTRACT FROM AUTHOR]