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Summary: A few Capsicum (pepper) species produce yellow‐colored floral nectar, but the chemical identity and biological function of the yellow pigment are unknown.A combination of analytical biochemistry techniques was used to identify the pigment that gives Capsicum baccatum and Capsicum pubescens nectars their yellow color. Microbial growth assays, visual modeling, and honey bee preference tests for artificial nectars containing riboflavin were used to assess potential biological roles for the nectar pigment.High concentrations of riboflavin (vitamin B2) give the nectars their intense yellow color. Nectars containing riboflavin generate reactive oxygen species when exposed to light and reduce microbial growth. Visual modeling also indicates that the yellow color is highly conspicuous to bees within the context of the flower. Lastly, field experiments demonstrate that honey bees prefer artificial nectars containing riboflavin.Some Capsicum nectars contain a yellow‐colored vitamin that appears to play roles in (1) limiting microbial growth, (2) the visual attraction of bees, and (3) as a reward to nectar‐feeding flower visitors (potential pollinators), which is especially interesting since riboflavin is an essential nutrient for brood rearing in insects. These results cumulatively suggest that the riboflavin found in some Capsicum nectars has several functions. [ABSTRACT FROM AUTHOR]

Quantifying genetic structure and levels of genetic variation are fundamentally important to predicting the ability of populations to persist in human‐altered landscapes and adapt to future environmental changes. Genetic structure reflects the dispersal of individuals over generations, which can be mediated by species‐level traits or environmental factors. Dispersal distances are commonly positively associated with body size and negatively associated with the amount of degraded habitat between sites, motivating the investigation of these potential drivers of dispersal concomitantly. We quantified genetic structure and genetic variability within populations of seven bee species from the genus Euglossa across fragmented landscapes. We genotyped bees at SNP loci and tested the following predictions: (1) deforested areas restrict gene flow; (2) larger species have lower genetic structure; (3) species with greater resource specialization have higher genetic structure; and (4) sites surrounded by more intact habitat have higher genetic diversity. Contrasting with previous work on bees, we found no associations between body size and genetic structure. Genetic structure was higher for species with greater resource specialization, and the amount of intact habitat between or surrounding sites was positively associated with parameters reflecting gene flow and genetic diversity. These results challenge the dominant paradigm that individuals of larger species disperse farther, and they suggest that landscape and resource requirements are important factors mediating dispersal. [ABSTRACT FROM AUTHOR]

Understanding the mechanisms by which wild bees survive in modified landscapes is important for their conservation and management as pollinators. Pollen is a critical resource for the completion of bee life cycles, so we investigated how the pollen loads carried by native bee communities change between natural forests and farms dominated by exotic crops and weeds in an agricultural region of south‐east Australia.We found that individual bees tended to carry higher proportions of exotic pollen on farms compared with forests (after accounting for whether they were captured on exotic or native flowers), and the diversity of pollen carried by bees did not differ significantly between native forest and farm sites or along native forest cover gradients. This suggests that the native bees found on farms, which are predominantly different species compared with those found in native forests, are not disadvantaged by the dominance of exotic plants in these habitats (though impacts on larval nutrition were not investigated).While some native bees carried crop pollen, others almost exclusively carried the pollen of agricultural weeds (e.g., Arctotheca and Brassica species), such that some native bee species may pollinate and benefit from crops, whereas others may only persist on farms if agricultural weeds are tolerated. [ABSTRACT FROM AUTHOR]

Pesticide use in agricultural landscapes creates environmental contamination that is heterogenous in space and time. Mobile organisms, such as bees, are exposed to multiple contamination sources when visiting patches that vary in the amount, timing and toxicity of pesticides used. Yet, environmental risk assessments (ERA) typically fail to consider this heterogeneity, in part because of the complexities of estimating exposure to different pesticides, and subsequent risk at organism‐relevant scales.We use pesticide assays of 269 bee‐collected pollen samples to understand the spatiotemporal variability of risk across a network of 41 field sites in southern Sweden. Observed bee pesticide risk is calculated based on compound‐specific residue quantifications in pollen and standardized toxicity data. We then compare the ability of three classes of landscape‐scale variables to predict this risk: (1) landscape composition and configuration metrics, (2) landscape load based on national pesticide use data and (3) predictions from a newly developed bee pesticide exposure model.Based on use data, 10 crops account for 81% of the total risk. We detected 49 pesticide compounds in bee‐collected pollen. Although herbicides and fungicides constitute the bulk of detected pesticides, both in frequency and amount quantified, unsurprisingly, insecticides contribute the most to risk.Landscape composition and configuration metrics did not predict observed pesticide risk, and interactions with bee species indicate taxa‐dependency in predictions. Landscape load predicted observed risk consistently between taxa. Risk estimates from our exposure model were strongly predictive but only when considering realized risk (i.e., risk estimates based on prior pesticide use information).Synthesis and applications. Predicting pesticide risk based on landscape patterns could enable landscape‐scale ERA. However, simple metrics of landscape pattern, such as proportion of agricultural land, are not sufficient. We found that risk observed in bee‐collected pollen was best predicted when integrating spatialized pesticide use in the pesticide exposure model, underscoring the importance of such data for research, monitoring and mitigation. Further, we propose a guidance framework for future landscape ecotoxicological risk analyses that clarifies data needs relative to risk prediction goals. [ABSTRACT FROM AUTHOR]

The decline of insect pollinators is a global concern, and the use of pesticides has been identified as a potential cause for it. Glyphosate‐based herbicides (GBHs) are the world's most used pesticides, but until recent years they have been claimed to be safe for non‐target organisms, such as pollinators. Using controlled arena experiments, we investigated the effects on the learning and long‐term memory of buff‐tailed bumblebees, Bombus terrestris (L.) (Hymenoptera: Apidae), of a single field‐realistic dose of glyphosate, both in its pure form and as a commercial herbicide (Roundup Gold) containing the active ingredient (a.i.) glyphosate and other co‐formulants. We found that glyphosate in its pure form caused deterioration in the learning ability of bumblebees in a 10‐color discrimination experiment; the glyphosate‐treated bees discriminated colors over 10% worse than the untreated control bees. However, the commercially used GBH (Roundup Gold) had no observable effect on the learning ability of the bumblebees, despite the fact that this herbicide contained the same amount of glyphosate as its pure form. These findings shed light on the potential risks associated with agrochemicals previously considered safe for pollinators and emphasize the need for comprehensive risk assessments of pesticides, including evaluations of cognitive functions in pollinators. Therefore, we propose that future pesticide testing should incorporate broader assessments to ensure the safety of pollinators in agricultural landscapes. [ABSTRACT FROM AUTHOR]

Species morphological and behavioural traits are key determinants of which pollinator species interact with which plant species. However, individuals within species are not identical in their traits and this diversity could help us understand plant–pollinator interaction patterns.Using three independent data sets, we assessed whether bee intraspecific body size variation (ITV) and sociality influenced pollinator interaction specialisation, intraspecific niche partitioning, centrality in the interaction network and phylogenetic diversity of the plants visited.We found that solitary pollinators were more specialised in their interactions with plants and had lower intraspecific niche partitioning compared to social pollinators. Furthermore, solitary pollinators with higher ITV had higher centrality in the network and visited a higher phylogenetic diversity of plants compared to solitary species with lower ITV, whereas the opposite pattern emerged for social pollinators. Pollinator ITV did not differ between social and solitary bee species.Our findings show that the effect of pollinator body size variation on plant–pollinator interactions depends on pollinator species sociality. Specifically, solitary pollinators with higher ITV and social pollinators with lower ITV seem to be the most important contributors to maintaining the evolutionary diversity of the plant community, and also the species with the largest potential to affect (via cascade effects) the entire plant–pollinator network. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Large‐scale disturbances such as wildfire can have profound impacts on the composition, structure, and functioning of ecosystems. Bees are critical pollinators in natural settings and often respond positively to wildfires, particularly in forests where wildfire leads to more open conditions and increased floral resources. The use of Light Detection and Ranging (LiDAR) provides opportunities for quantifying habitat features across large spatial scales and is increasingly available to scientists and land managers for post‐fire habitat assessment. We evaluated the extent to which LiDAR‐derived forest structure measurements can predict forest bee communities after a large, mixed‐severity fire. We hypothesized that LiDAR measurements linked to post‐fire forest structure would improve our ability to predict bee abundance and species richness when compared to satellite‐based maps of burn severity. To test this hypothesis, we sampled wild bee communities within the Douglas Fire Complex in southwestern Oregon, USA. We then used LiDAR and Landsat data to quantify forest structure and burn severity, respectively, across bee sampling locations. We found that the LiDAR forest structure model was the best predictor of abundance, whereas the Landsat burn severity model had better predictive ability for species richness. Furthermore, the Landsat burn severity model was better at predicting the presence and species richness of bumble bees (Bombus spp.), an ecologically distinct and economically important group within the Pacific Northwest. We posit that the divergent responses of the two modeling approaches are due to distinct responses by bee taxa to variation in forest structure as mediated by wildfire, with bumble bees in particular depending on closed‐canopy forest for some portions of their life cycle. Our study demonstrates that LiDAR data can provide information regarding the drivers of bee abundance in post‐wildfire conifer forest, and that both remote sensing approaches are useful for predicting components of wild bee diversity after large‐scale wildfire. [ABSTRACT FROM AUTHOR]

Habitat loss is a primary driver of biodiversity decline, but differences in species responses to habitat loss from local to landscape scales are poorly understood.Trophic level, food and habitat specialization have been suggested to be important predictors of species responses to habitat loss, landscape diversity and landscape scale.Using cavity‐nesting communities of bees, wasps and their parasitoids on calcareous grasslands as a model system allowed us to compare responses of species differing regarding their trophic level, and degree of specialization on habitat and food.We found that species from higher trophic levels experienced semi‐natural habitat at larger spatial scales than those of lower trophic levels, but only, when they were generalists (abundance of bees, 150 m radius, vs. wasps feeding on herbivores, 450 m radius), not specialists (bees, 150 m, vs. bee parasitoids, 150 m).Parasitoids, which are typically more specialized regarding their food resources (hosts), compared to predators such as predatory wasps, responded to habitat loss at the same spatial scales as their hosts, suggesting strong bottom‐up effects of resource availability, that is, host availability driving parasitoid abundance.Bees were mostly habitat specialists of calcareous grasslands and mainly driven by local habitat loss, whereas wasps as habitat generalists were mostly affected by landscape diversity.Our study highlights the need to consider the different spatial scales contingent on trophic level and specialization of target species groups, maintaining or restoring both local habitat and landscape diversity, as this is needed for their successful conservation. [ABSTRACT FROM AUTHOR]

Microbiomes are increasingly recognised as critical for the health of an organism. In eusocial insect societies, frequent social interactions allow for high‐fidelity transmission of microbes across generations, leading to closer host–microbe coevolution. The microbial communities of bees with other social lifestyles are less studied, and few comparisons have been made between taxa that vary in social structure. To address this gap, we leveraged a cloud‐computing resource and publicly available transcriptomic data to conduct a survey of microbial diversity in bee samples from a variety of social lifestyles and taxa. We consistently recover the core microbes of well‐studied corbiculate bees, supporting this method's ability to accurately characterise microbial communities. We find that the bacterial communities of bees are influenced by host location, phylogeny and social lifestyle, although no clear effect was found for fungal or viral microbial communities. Bee genera with more complex societies tend to harbour more diverse microbes, with Wolbachia detected more commonly in solitary tribes. We present a description of the microbiota of Euglossine bees and find that they do not share the "corbiculate core" microbiome. Notably, we find that bacteria with known anti‐pathogenic properties are present across social bee genera, suggesting that symbioses that enhance host immunity are important with higher sociality. Our approach provides an inexpensive means of exploring microbiomes of a given taxa and identifying avenues for further research. These findings contribute to our understanding of the relationships between bees and their associated microbial communities, highlighting the importance of considering microbiome dynamics in investigations of bee health. [ABSTRACT FROM AUTHOR]

Natural and protected area degradation constitutes a threat to bee communities and could decrease crop yield by reducing bee pollination effectiveness. For West Africa, changes in bee communities across disturbance gradients from savannah to agricultural land are mainly unknown. Our study aimed to assess the impact of land use patterns on bee communities in the department of Korhogo. We chose three sites of varying disturbance intensity (low, medium and high disturbance). Bees were caught using pan traps. Abundance, richness, evenness and community structure of bees were assessed. During 6 months of sampling, 3176 bee specimens belonging to three families (Apidae, Halictidae and Megachilidae) were caught, comprising 18 species and 15 genera. Species richness of Halictidae and abundance of Apidae were highest (F = 93.86; p = 0.0051). The station with low disturbance was more diversified (H′ = 2.75). Bee average abundance was higher in sites with medium disturbance. Our findings are relevant to biodiversity conservation. They show that bee diversity is high where the disturbance level is still low. [ABSTRACT FROM AUTHOR]

Urbanization is a global phenomenon that can affect fitness and could challenge the persistence of most species, including wild bee pollinators. Yet, how and which environmental features affect bee health and fitness within the urban ecosystem remain unclear.Here, we placed experimental Bombus terrestris colonies in sites spanning from the edge into a city's core to investigate bumble bee parasitism, foraging behaviour, energetic stress, colony growth and reproductive output. In each site, ambient temperature was recorded, the availability of floral resources was evaluated and landscape heterogeneity was characterized using land‐cover maps.We found that Bombus terrestris parasitism levels increased across the season in line with colony growth but were negatively related to the proportion of impervious surfaces surrounding a site. Bombus terrestris foraging trip duration decreased with increasing ecotones (edge density) but, conversely, increased in sites with honey bee hives present. Energetic stress was evaluated as lowered trehalose titre in the haemolymph of returning foragers; stress increased with the proportion of impervious surfaces. Furthermore, our analyses identified ambient temperature to be a strong predictor of Bombus terrestris colony performance in that high ambient temperature reduced colony growth and indirectly the production of sexual offspring (gynes).Our results highlight the importance of ecotones as well as minimizing the intensity of urbanization and urban honey bee beekeeping for bumble bee colony health and foraging behaviour. They also point to the importance of microclimate (i.e. temperature) for bumble bee colony performance and suggest that increasing temperatures could have a negative impact in slowing colony weight gain, and indirectly in reducing colony reproduction. [ABSTRACT FROM AUTHOR]

Multiple trade‐offs likely occur between pesticide use, pollinators and yield (via crop flowers) in pollinator‐dependent, mass‐flowering crops (MFCs), causing potential conflict between conservation and agronomic goals. To date, no studies have looked at both outcomes within the same system, meaning win‐win solutions for pollinators and yield can only be inferred.Here, we outline a new framework to explore these trade‐offs, using red clover (Trifolium pratense) grown for seed production as an example. Specifically, we address how the insecticide thiacloprid affects densities of seed‐eating weevils (Protapion spp.), pollination rates, yield, floral resources and colony dynamics of the key pollinator, Bombus terrestris.Thiacloprid did not affect the amount of nectar provided by, or pollinator visitation to, red clover flowers but did reduce weevil density, correlating to increased yield and gross profit. In addition, colonies of B. terrestris significantly increased their weight and reproductive output in landscapes with (compared with without) red clover, regardless of insecticide use.Synthesis and applications. We propose a holistic conceptual framework to explore trade‐offs between pollinators, pesticides and yield that we believe to be essential for achieving conservation and agronomic goals. This framework applies to all insecticide‐treated mass‐flowering crops (MFCs) and can be adapted to include other ecological processes. Trialling the framework in our study system, we found that our focal insecticide, thiacloprid, improved red clover seed yield with no detected effects on its key pollinator, B. terrestris, and that the presence of red clover in the landscape can benefit pollinator populations. [ABSTRACT FROM AUTHOR]

Aim: Plant populations are declining in their native ranges around the globe through the expansion of agriculture, urbanization, and plant invasions. We test the hypothesis that animal species that have spent more of their evolutionary history in a region are more dependent on native plants, particularly those plants that have spent more of their evolutionary history in the region, and are therefore more negatively impacted by native plant decline. Location: Yarra Valley landscapes, Australia. Methods: We test the presence and pattern of phylogenetic signal in native bee community responses to local flower density of ancient Australian plant lineages and the amount of native vegetation in the surrounding landscape across farm and native vegetation sites. We also test phylogenetic signal in the frequency of bee visitation to flowers from ancient Australian plant lineages. We compare the patterns of phylogenetic signal to the current understanding of bee biogeographic histories to evaluate our hypothesis. Results: There was significant phylogenetic signal in responses to flower density of plants from ancient Australian lineages, and the frequency of visitation to these flowers, with most species from the ancient Australian bee clade being positively associated with these flowers. This is consistent with our hypothesis. Significant phylogenetic signal in response to native vegetation in the surrounding landscape was driven primarily by the more recently arrived bee linages, with ancient lineages able to persist on some farms where ancient Australian flowers were present (e.g. on roadsides). Main conclusions: Bee species that have spent more of their evolutionary history in Australia are more dependent on ancient Australian plant lineages and so most negatively impacted by the decline of these plants. This may be a broader phenomenon because phylogenetic conservatism in host plant use, the main assumption underlying our hypothesis, is common among herbivorous arthropods (~500,000 species). [ABSTRACT FROM AUTHOR]

A crucial issue for landscape ecologists is identifying the spatial extents at which a landscape affects species occurrence. Multi‐scale analyses are usually conducted to identify the 'scale of effect', that is, the spatial extent associated with the best relationship between landscape variables and species occurrence, which is assumed to be related to species traits. However, few guidelines exist to determine the range of distances to be investigated. Based on the foraging distances of wild bee species, our main goal was to estimate the maximum distance of effect, that is, the distance beyond which the scale of effect for wild bee species is unlikely to be detected. Using the InVEST pollination model, we 1) modelled bee categories with distinct foraging distances and identified the scale of effecton their simulated abundance 2) defined an index, noted λ, that estimates the distance beyond which landscape composition has only negligible effects on simulated abundances. We validated our results by identifying the scale of effecton the abundances of 16 bee species collected in south‐western France. We detected a significant positive relationship between the average foraging distance (α) of the modelled bees and their scale of effect. The λ index was linearly related to the average foraging distances of bees (λ = 5.4α + 253) and was above the identified scale of effect for the modelled bees. The λ was also found to be above the scale of effect for 93% of the observed bee species. Our results suggest that the λ index is a good estimator of the upper limit of the scale of effect for wild bees. The λ index could be used to identify the minimum distance between sampling sites before setting up an experiment and the maximum buffer size required in multi‐scale analysis to detect the scale of effect. [ABSTRACT FROM AUTHOR]

Many hummingbird‐pollinated plant species evolved from bee‐pollinated ancestors independently in many different habitats in North and South America. The mechanisms leading to these transitions are not completely understood. We conducted pollination and germination experiments and analyzed additional reproductive traits in three sister species pairs of which one species is bee‐ and the other hummingbird‐pollinated. All hummingbird‐pollinated species showed higher seed set and germination rates in cross‐pollinated than in self‐pollinated flowers. In the self‐compatible, bee‐pollinated sister species this difference did not exist. As expected, seed set and germination rate were higher after cross‐pollination in the largely self‐incompatible genus Penstemon independently of the pollination syndrome. However, the bird‐pollinated species produce only half of the amount of ovules and pollen grains per flower compared to the bee‐pollinated sister species. This indicates that hummingbird pollination is much more efficient in self‐incompatible populations because hummingbirds waste less pollen and provide higher outcrossing rates. Therefore, hummingbird pollination is less resource costly. Overall, we suggest that hummingbirds may increase the reproductive success compared to bees, influencing the evolution of hummingbird pollination in ecosystems with diverse bee assemblages. [ABSTRACT FROM AUTHOR]

Bees experience differences in thermal tolerance based on their geographical range; however, there are virtually no studies that examine how overwintering temperatures may influence immature survival rates. Here, we conducted a transplant experiment along an elevation gradient to test for climate‐change effects on immature overwinter survival using movement along elevational gradient for a community of 26 cavity‐nesting bee species in the family Megachilidae along the San Francisco Peaks, Arizona elevational gradient. In each of three years, we placed nest blocks at three elevations, to be colonized by native Megachilidae. Colonized blocks were then (1) moved to lower (warmer) elevations; (2) moved to higher (cooler) elevations; or (3) left in their natal habitat (no change in temperature). Because Megachilidae occupy high elevations with colder temperatures more than any other family of bees, we predicted that emergence would decrease in nest blocks moved to lower elevations, but that we would find no differences in emergence when nest blocks were moved to higher elevations. We found three major results: (1) Bee species moved to lower (warmer) habitats exhibited a 30% decrease in emergence compared with species moved within their natal habitat. (2) Habitat generalists were more likely than habitat specialists to emerge when moved up or down in elevation regardless of their natal life zones. (3) At our highest elevation treatment, emergence increased when blocks were moved to higher elevations, indicating that at least some Megachilidae species can survive at colder temperatures. Our results suggest that direct effects of warming temperatures will have negative impacts on the overall survival of Megachilidae. Additionally, above the tree line, low availability of wood‐nesting resources is a probable limiting factor on bees moving up in elevation. [ABSTRACT FROM AUTHOR]

As hybrid zones exhibit selective patterns of gene flow between otherwise distinct lineages, they can be especially valuable for informing processes of microevolution and speciation. The bumble bee, Bombus melanopygus, displays two distinct color forms generated by Müllerian mimicry: a northern "Rocky Mountain'' color form with ferruginous mid‐abdominal segments (B. m. melanopygus) and a southern "Pacific'' form with black mid‐abdominal segments (B. m. edwardsii). These morphs meet in a mimetic transition zone in northern California and southern Oregon that is more narrow and transitions further west than comimetic bumble bee species. To understand the historical formation of this mimicry zone, we assessed color distribution data for B. melanopygus from the last 100 years. We then examined gene flow among the color forms in the transition zone by comparing sequences from mitochondrial COI barcode sequences, color‐controlling loci, and the rest of the nuclear genome. These data support two geographically distinct mitochondrial haplogroups aligned to the ancestrally ferruginous and black forms that meet within the color transition zone. This clustering is also supported by the nuclear genome, which, while showing strong admixture across individuals, distinguishes individuals most by their mitochondrial haplotype, followed by geography. These data suggest the two lineages most likely were historically isolated, acquired fixed color differences, and then came into secondary contact with ongoing gene flow. The transition zone, however, exhibits asymmetries: mitochondrial haplotypes transition further south than color pattern, and both transition over shorter distances in the south. This system thus demonstrates alternative patterns of gene flow that occur in contact zones, presenting another example of mito‐nuclear discordance. Discordant gene flow is inferred to most likely be driven by a combination of mimetic selection, dominance effects, and assortative mating. [ABSTRACT FROM AUTHOR]

Epitranscriptomics is an emerging field of investigation dedicated to the study of post‐transcriptional RNA modifications. RNA methylations regulate RNA metabolism and processing, including changes in response to environmental cues. Although RNA modifications are conserved from bacteria to eukaryotes, there is little evidence of an epitranscriptomic pathway in insects. Here we identified genes related to RNA m6A (N6‐methyladenine) and m5C (5‐methylcytosine) methylation machinery in seven bee genomes (Apis mellifera, Melipona quadrifasciata, Frieseomelitta varia, Eufriesea mexicana, Bombus terrestris, Megachile rotundata and Dufourea novaeangliae). In A. mellifera, we validated the expression of methyltransferase genes and found that the global levels of m6A and m5C measured in the fat body and brain of adult workers differ significantly. Also, m6A levels were differed significantly mainly between the fourth larval instar of queens and workers. Moreover, we found a conserved m5C site in the honeybee 28S rRNA. Taken together, we confirm the existence of epitranscriptomic machinery acting in bees and open avenues for future investigations on RNA epigenetics in a wide spectrum of hymenopteran species. [ABSTRACT FROM AUTHOR]

Bees are major pollinators of angiosperms and have phylogenetically conserved colour vision but differ in how various key species use achromatic information that is vital for both flower detection and size processing.We modelled green contrast and colour contrast signals from flowers of different countries where there are well established differences in availability of model bee species along altitudinal gradients. We tested for consistency in visual signals as expected from generalization in pollination principles using phylogenetically informed linear models.Patterns of chromatic contrast, achromatic green contrast and flower size differed among the three floras we examined. In Nepal there is a significant positive correlation between flower size and colour contrast in the subalpine region, but a negative correlation at the lower altitudes. At high elevations in Norway, where pollinators other than bees are common, flower size was positively correlated with colour contrast. At low and medium altitudes in Norway and in Australia, we did not observe a significant relationship between size and colour contrast.We thus find that the relationship between size, green and colour contrast cannot be generalized across communities, thus suggesting that flower visual signal adaptations to local pollinators are not limited to chromatic contrast. [ABSTRACT FROM AUTHOR]

Premise: Animal pollination is critical to plant reproduction and may cause convergent evolution of pollination syndromes. Pollination syndromes in Castilleja have been distinguished based on floral traits and historical observations of floral visitors. Here we addressed these questions: (1) Can pollination syndromes be distinguished using floral morphological traits or volatile organic compound emissions? (2) Is there significant variation in floral traits within a pollination syndrome at the level of populations or species? (3) Do pollination syndromes predict the most frequent floral visitor to Castilleja? Methods: Floral traits and visitation were measured for five co‐occurring Castilleja species (C. applegatei, C. linariifolia, C. miniata, C. nana, and C. peirsonii), representing three pollination syndromes (bee, fly, and hummingbird), at four sites in the Sierra Nevada Mountains. We used nonmetric multidimensional scaling (NMDS) and multiple linear regressions to address key questions in the differentiation of Castilleja and floral visitors. Results: Our analyses revealed that both morphological traits and floral VOCs can be used to distinguish between some pollination syndromes and Castilleja species. Morphological traits defined pollination syndromes reliably, but within the hummingbird syndrome, there was also significant variation among populations and species. Pollination syndrome was a poor predictor of visitors to Castilleja. Conclusions: Floral trait differentiation among Castilleja individuals reflects both taxonomy and pollination syndromes. Differentiation was generally more evident in morphological traits compared to VOCs. Furthermore, a priori notions of pollination syndromes in this system are overly simplistic and fail to predict which animals most frequently visit Castilleja in natural populations. [ABSTRACT FROM AUTHOR]

Premise: Many animals provide ecosystem services in the form of pollination including honeybees, which have become globally dominant floral visitors. A rich literature documents considerable variation in single visit pollination effectiveness, but this literature has yet to be extensively synthesized to address whether honeybees are effective pollinators. Methods: We conducted a hierarchical meta‐analysis of 168 studies and extracted 1564 single visit effectiveness (SVE) measures for 240 plant species. We paired SVE data with visitation frequency data for 69 of these studies. We used these data to ask three questions: (1) Do honeybees (Apis mellifera) and other floral visitors differ in their SVE? (2) To what extent do plant and pollinator attributes predict differences in SVE between honeybees and other visitors? (3) Is there a correlation between visitation frequency and SVE? Results: Honeybees were significantly less effective than the most effective non‐honeybee pollinators but were as effective as the average pollinator. The type of pollinator moderated these effects. Honeybees were less effective compared to the most effective and average bird and bee pollinators but were as effective as other taxa. Visitation frequency and SVE were positively correlated, but this trend was largely driven by data from communities where honeybees were absent. Conclusions: Although high visitation frequencies make honeybees important pollinators, they were less effective than the average bee and rarely the most effective pollinator of the plants they visit. As such, honeybees may be imperfect substitutes for the loss of wild pollinators, and safeguarding pollination will benefit from conservation of non‐honeybee taxa. [ABSTRACT FROM AUTHOR]

Current methods for direct tracking of individual bee movement behaviour have several limitations. In particular, the weight and size of some types of electronic tag may limit their use to larger species. Radars and other electronic systems are also often large and very expensive to deploy. A tool is needed that complements these electronic‐tag methods. In particular, one that is simple to use, low‐cost, can have a high spatial resolution and can be used with smaller insects.This paper presents a candidate method that uses retroreflective tags. These are detected using a camera with a global electronic shutter, with which we take photos with and without a flash. The tags can be detected by comparing these two photos. The small retroreflective tags are simple and lightweight, allowing many bees to be tagged at almost no cost and with little effect on their behaviour.We demonstrate this retroreflector‐based tracking system (RTS) with a series of simple experiments: Training and validation with a manually positioned tag, case studies of individual bees, tracking multiple bees as they forage in a garden, use of real‐time monitoring to allow easy reobservation to enable a simple floral preference experiment and a very brief experiment with 3D path reconstruction (integrating two devices). We found we could detect bees to a range of about 35 m with the current configuration.We envisage the system will be used in the future to increase detection rates in mark–reobservation studies, provide 3D flight path analysis and for automated long‐term monitoring. In summary, this novel tracking method has advantages that complement those of electronic‐tag tracking which we believe will lead to new applications and areas of research. [ABSTRACT FROM AUTHOR]

Chrysophyllum (Chrysophylloideae, Chrysophylleae) is the second largest genus in the Sapotaceae. Studies of pollination ecology in this genus are non‐existent, although there are records of entomophily for this family. Considering the lack of detailed studies on pollination ecology and sexual systems in Chrysophyllum species, we investigate the floral morphology and biology and floral visitors of Chrysophyllum marginatum to verify which sexual system is present in the studied population and whether flowers of this species are visited and pollinated by different insect groups. The population of C. marginatum has weak and cryptic gynomonoecy because the plants produce a low percentage of functionally pistillate flowers (4.2%) and these flowers appear to be perfect flowers (hermaphrode). Flowers of C. marginatum are phenotypically, ecologically and functionally generalist because: (a) they are actinomorphic, open and not restrictive in terms of access to floral resources; (b) they are visited by 26 species of insects that are potential pollinators; and (c) among these species several groups can be effective pollinators, mainly bees and flies, according to the most effective pollinator principle. We consider bees and flies to be the main pollinator group of C. marginatum, due to their high visitation rate, richness and intrafloral visiting behavior, and because they especially forage among plant individuals and are able to promote xenogamy. Nectaries were found in the ovary base and osmophores in the petal margins, as floral attractants. For Chrysophyllum, this is the first record of gynomonoecy and for the family this is considered the second record. Chrysophyllum marginatum has generalist and entomophilous pollination, as recorded in other Sapotaceae Neotropical species. [ABSTRACT FROM AUTHOR]

Apples are a major crop globally, including in Tasmania (Australia) – known as 'the Apple Isle' owing to the key role of apples in Tasmania's history and economy. Most apple cultivars are obligate entomophilous species, and fruit quantity, quality and economic value are enhanced under insect pollination. Whilst the introduced European honey bee (Apis mellifera) is often assumed to be the main pollinator of apple in most regions of the world, including Australia, there is an increasing interest in alternative pollinators. The pollinator community of Tasmanian apple crops, however, has never been assessed. In this study, we surveyed four apple orchards for 3 days each during peak bloom in the Huon Valley region to characterise bee assemblages visiting blooming apple trees and the native bee fauna associated with surrounding flowering vegetation. Our results show that honey bees were the predominant visitors to apple blossoms (90.7% of visits), followed by the introduced bumble bee Bombus terrestris (5.9% of visits), with only a minor contribution by native bees (3.3% of visits). Twenty‐six species of native bees were collected in total, of which only 10 species (five Exoneura (Apidae), four Lasioglossum (Halictidae) and one Euryglossa (Colletidae) species) were collected from apple blossoms, with Exoneura being the most abundant visitors. Few native bees were captured on apple blossoms, however co‐blooming surrounding native vegetation, as well exotic flowers, hosted a high diversity and abundance of native bees. Site conditions influenced community composition, including abundance and representation of introduced bees compared to native bees visiting apples. Additionally, warmer temperatures favoured native bees. Collectively, our results suggest that Tasmania's apple production in its current state is unlikely to rely exclusively on native pollinators. Native bees nevertheless warrant conservation in such an insular crop production system. This can be achievable through retaining native flowering plants and even exotic non‐crop flowers in and around orchards. Promoting the diversity and abundance of native bees through habitat enhancement may have additional benefits, such as filling current and future pollination demands and gaps, a key strategy under scenarios of climate change. [ABSTRACT FROM AUTHOR]

Bee responses to anthropogenic disturbances have received much recent attention in scientific literature. These studies typically involve 1–3 years of sampling along spatial gradients of disturbance, though occasionally greater temporal replication and/or longer time periods are used at the expense of spatial replication. We surveyed bees using a blue vane trap during spring, summer and autumn from 2008 to 2017 at one location in Canberra, Australia. To the best of our knowledge, this is the longest near‐continuous record of bee activity in the southern hemisphere. We use these data to describe the temporal dynamics of the bee community, which was characterised by high annual variability in overall abundance, richness and composition and a negative correlation between spring rainfall and bee activity. The phenologies of abundant species are also described. Our findings relate only to our study site but are similar to findings from other long‐term studies conducted in the northern hemisphere, which collectively present a picture of high natural variability in bee communities that must be considered when interpreting findings of bee responses to anthropogenic disturbances. [ABSTRACT FROM AUTHOR]

Global insect pollinator declines have prompted habitat restoration efforts, including pollinator‐friendly gardening. Gardens can provide nectar and pollen for adult insects and offer reproductive resources, such as nesting sites and caterpillar host plants. We conducted a review and meta‐analysis to examine how decisions made by gardeners on plant selection and garden maintenance influence pollinator survival, abundance, and diversity. We also considered characteristics of surrounding landscapes and the impacts of pollinator natural enemies. Our results indicated that pollinators responded positively to high plant species diversity, woody vegetation, garden size, and sun exposure and negatively to the separation of garden habitats from natural sites. Within‐garden features more strongly influenced pollinators than surrounding landscape factors. Growing interest in gardening for pollinators highlights the need to better understand how gardens contribute to pollinator conservation and how some garden characteristics can enhance the attractiveness and usefulness of gardens to pollinators. Further studies examining pollinator reproduction, resource acquisition, and natural enemies in gardens and comparing gardens with other restoration efforts and to natural habitats are needed to increase the value of human‐made habitats for pollinators. Article Impact Statement: Gardens with high plant species diversity and sun exposure, more woody vegetation, and larger size benefit pollinators. [ABSTRACT FROM AUTHOR]

Sulfoximine‐based insecticides, such as sulfoxaflor, are of increasing global importance and have been registered for use in 81 countries, offering a potential alternative to neonicotinoid insecticides.Previous studies have demonstrated that sulfoxaflor exposure can have a negative impact on the reproductive output of bumblebee colonies, but the specific life‐history variables that underlie these effects remain unknown.Here, we used a microcolony‐based protocol to assess the sub‐lethal effects of chronic sulfoxaflor exposure on egg laying, larval production, ovary development, sucrose consumption, and mortality in bumblebees. Following a pre‐registered design, we exposed colonies to sucrose solutions containing 0, 5, 10 and 250ppb of sulfoxaflor. Exposure at 5 ppb has been previously shown to negatively impact colony reproductive success.Our results showed that sulfoxaflor exposure at 5 ppb (lowest exposure tested) reduced the number of eggs found within the microcolonies (Hedge's d = −0.37), with exposed microcolonies also less likely to produce larvae (Hedge's d = −0.36). Despite this, we found no effect of sulfoxaflor exposure on ovarian development. Sulfoxaflor‐exposed bumblebees consumed less sucrose solution, potentially driving the observed reduction in egg laying.Policy implications. Regulatory bodies such as the European Food Safety Authority (EFSA) are under increasing pressure to consider the potential impact of insecticides on wild bees, such as bumblebees, but sublethal effects can go undetected at lower‐tier testing. In identifying just such an effect for bumblebees exposed to sulfoxaflor, this study highlights that microcolony‐based protocols are a useful tool that could be implemented within an ecotoxicology framework. Furthermore, the results provide evidence for potentially negative consequences of pollinator exposure to an insecticide that is currently undergoing the licensing process in several EU member states. [ABSTRACT FROM AUTHOR]

Habitat management methods are crucial to maintaining habitats in the long term and ensuring vital resources are available for declining species. However, when management focuses on a single resource there is the potential to reduce or degrade other critical resources and negatively affect species of concern. Although both floral and nesting resources are critical to supporting bee populations, little consideration is given to the availability of nesting resources. Given known effects of management methods on soils, where the majority of bees nest, and floral food resources, increasing our understanding of management effects on both soils and floral resources is important to improving bee conservation efforts.In 20 tallgrass prairie plots managed under 1 of 3 common methods: burning, haying and patch‐burn grazing, we assessed effects on bee communities and necessary above‐ and below‐ground resources. We also considered how management and resources affected below‐ground nesting in each prairie.Management type affected both soil conditions and floral resources with patch‐burn grazing sites providing overall worse resources for bees compared to ungrazed sites. Soil conditions were also important for predicting most aspects of the bee community including abundance and community composition. Soil conditions also decreased floral richness and Floristic Quality Index (FQI). This suggests management affects bee communities both directly and indirectly through soil.Increased nesting was observed in sites with greater floral abundance and soil conditions that correspond to increased bare ground, lower soil moisture and warmer soil temperatures suggesting management that helps increase floral abundance and improve soil conditions could be critical to increasing bee nesting.Synthesis and applications. Measuring and tracking bare ground, Floristic Quality Index (FQI) and floral richness may help managers determine if their management methods are adversely affecting bees. Grazing and haying management negatively affected the bee community, vital nesting and floral resources and nesting rate. These managements may need to be avoided to meet bee conservation goals in prairies. Additionally, while soils have been largely overlooked, we found soil conditions to be an important predictor for bee communities and floral resources, and should be considered more explicitly in conserved areas. [ABSTRACT FROM AUTHOR]

Lateralisation of biological form and function are well known for vertebrates and are being increasingly documented among invertebrates in recent years. Behavioural lateralisation in insects, together with asymmetrical distributions of antennal sensilla, has been linked to the communication challenges faced by social, but not solitary, insects. Recent evidence on patterns of asymmetry in insects outside of the Hymenoptera suggests that this explanation for antennal sensilla asymmetry may not be phylogenetically constrained. We explore this possibility by examining the distribution of antennal sensilla in three species of ants (Formicidae), the meat ant Iridomyrmex purpureus (Dolichoderinae), the green tree ant Oecophylla smaragdina (Formicinae) and the shield ant Meranoplus sp. (Myrmicinae) in which colony organisation is eusocial, and two species of nomiine bees, Mellitidia tomentifera and Reepenia bituberculata (Halictidae: Nomiinae), where colony organisation is not eusocial. Our results demonstrate that while there are differences in the left–right asymmetry of antennal sensilla basiconica in workers of the formicine ant I. purpureus, there is no consistent sensilla asymmetry across the five species. We find a negative correlation between antennal sensilla density and body size in R. bituberculata, which was not apparent in the other species. Our results contradict the suggestion that asymmetrical distribution of antennal sensilla is associated with the evolution of eusocial behaviour. [ABSTRACT FROM AUTHOR]

Simple and conditional discrimination training may produce various types of controlling relations. Responses may be controlled primarily by the positive stimulus (select–control relation) or by the negative stimulus (reject–control relation; the subject excludes the negative stimulus and chooses the positive). Bees learn to respond in simple and conditional discriminations. However, no study has searched for reject–control responding in Melipona bees. We trained Melipona quadrifasciata on a simple discrimination task (S+ vs. S‐; e.g., blue vs. yellow) and then probed for stimulus control with two types of probe trials, S+ versus a new stimulus (Select–control probes) and S‐ versus a new stimulus (Reject–control probes). For Group Different, a new‐stimulus color (e.g., white) was used in one type of probe and another color (e.g., black) was used in the other type. For Group Same, a single new‐stimulus color was used in both types of probes. On Select probes, the bees always preferred S+ to the new stimulus. On Reject probes, results were mixed. Depending on the colors used in training and probing, bees responded to both stimuli, and even preferred the S‐. The data suggest no control by the negative function of the S‐ and support the select‐stimulus control hypothesis of responding. [ABSTRACT FROM AUTHOR]

Bee‐friendly plants are defined by the quantity of food they produce and the visitation rates of adult insects foraging for nectar. However, it is pollen nutritional quality that enables proper larval development of bees, affecting their populations. Not all plants produce pollen that satisfies the nutritional requirements of bee larvae, and we lack an understanding of how different plant pollens impact bee nutritional demands. This study examined whether nutritionally desirable key plant species may promote wild bee larval development, which is essential if the population is to thrive.The generalist solitary mason bee Osmia bicornis L. was used as a model species to examine differences between bee larva nutritional demand and host plant nutrient supply; an ecological stoichiometry framework was applied. The stoichiometric ratios of 12 elements were investigated in bee bodies and cocoons (reflecting nutritional demand) and in the pollen supplied by the mother (nutritional supply; N = 15 × 2 sexes). Similarly, the stoichiometry of 62 pollen taxa, including native, alien, and garden plants and crops, was compared with the bee demand based on the literature.Compared to males, females had higher demands for P, Cu and Zn and were supplied with pollen richer in these elements. Therefore, when collecting pollen for their progeny, Osmia provides daughters and sons with different pollen mixtures, reflecting sex‐specific nutritional demand.Bees may be limited by the availability of P, Na, Mn, Mg, K, Fe, Ca, Zn and Cu, with high taxonomic variability in their concentrations in pollen. Female fitness may be particularly related to a high proportion of P in the diet.Synthesis and applications. Access to key plant species that allow nutritionally balanced larval diets may be essential for bee development, whether food is gathered intentionally or randomly. Such plant species—and not only those rich in nectar and pollen—should be promoted in wild bee conservation efforts, including planting flower strips and hedgerows. Bee‐friendly plants should not be defined and planted solely based on the quantities of food they produce and on the visitation rates of adult insects foraging for energy. Access to key plant species that allow nutritionally balanced larval diets may be essential for bee development, whether food is gathered intentionally or randomly. Such plant species—and not only those rich in nectar and pollen—should be promoted in wild bee conservation efforts, including planting flower strips and hedgerows. Bee‐friendly plants should not be defined and planted solely based on the quantities of food they produce and on the visitation rates of adult insects foraging for energy. [ABSTRACT FROM AUTHOR]

In focusing on how organisms' generalizable functional properties (traits) interact mechanistically with environments across spatial scales and levels of biological organization, trait‐based approaches provide a powerful framework for attaining synthesis, generality and prediction. Trait‐based research has considerably improved understanding of the assembly, structure and functioning of plant communities. Further advances in ecology may be achieved by exploring the trait–environment relationships of non‐sessile, heterotrophic organisms such as terrestrial arthropods, which are geographically ubiquitous, ecologically diverse, and often important functional components of ecosystems. Trait‐based studies and trait databases have recently been compiled for groups such as ants, bees, beetles, butterflies, spiders and many others; however, the explicit justification, conceptual framework, and primary‐evidence base for the burgeoning field of 'terrestrial arthropod trait‐based ecology' have not been well established. Consequently, there is some confusion over the scope and relevance of this field, as well as a tendency for studies to overlook important assumptions of the trait‐based approach. Here we aim to provide a broad and accessible overview of the trait‐based ecology of terrestrial arthropods. We first define and illustrate foundational concepts in trait‐based ecology with respect to terrestrial arthropods, and justify the application of trait‐based approaches to the study of their ecology. Next, we review studies in community ecology where trait‐based approaches have been used to elucidate how assembly processes for terrestrial arthropod communities are influenced by niche filtering along environmental gradients (e.g. climatic, structural, and land‐use gradients) and by abiotic and biotic disturbances (e.g. fire, floods, and biological invasions). We also review studies in ecosystem ecology where trait‐based approaches have been used to investigate biodiversity–ecosystem function relationships: how the functional diversity of arthropod communities relates to a host of ecosystem functions and services that they mediate, such as decomposition, pollination and predation. We then suggest how future work can address fundamental assumptions and limitations by investigating trait functionality and the effects of intraspecific variation, assessing the potential for sampling methods to bias the traits and trait values observed, and enhancing the quality and consolidation of trait information in databases. A roadmap to guide observational trait‐based studies is also presented. Lastly, we highlight new areas where trait‐based studies on terrestrial arthropods are well positioned to advance ecological understanding and application. These include examining the roles of competitive, non‐competitive and (multi‐)trophic interactions in shaping coexistence, and macro‐scaling trait–environment relationships to explain and predict patterns in biodiversity and ecosystem functions across space and time. We hope this review will spur and guide future applications of the trait‐based framework to advance ecological insights from the most diverse eukaryotic organisms on Earth. [ABSTRACT FROM AUTHOR]

Abstract: Large flower plantings are often used to combat negative effects of habitat loss on pollinators, but whether these floral additions are effective at smaller scales remains unclear, particularly in urban settings. To test the effectiveness of small‐scale floral additions on enhancing urban bee populations, as well as their impact from 1 year to the next, different quantities of potted sweet alyssum (Lobularia maritima) flowers were placed across sites in Ann Arbor, Michigan for two consecutive years and the resulting Halictid bee visitors were monitored. Overall, we found the number of flowers added at the local level was significantly and positively correlated with small Halictid bee abundance and species density in an urban landscape. At smaller flower quantities, dynamics were clearly linear, where incremental increases in number of flowers showed significant increases in bee abundance and species density. At larger quantities of floral additions, however, dynamics were nonlinear in that incremental increases in flower quantity had no effect on bee abundance and highly variable effects on bee species density. When comparing the change in small Halictid bee abundance and species density from 1 year to the next, we found a significant increase in bee species density in the second year of small‐scale floral additions, but no significant difference in bee abundance. Synthesis and applications. Our results show that small flower plantings can have positive effects on small bee communities in urban systems even over a short period of time and therefore confirm that encouraging citizens to plant flowers can be an effective conservation strategy for certain urban pollinator populations. In addition, our finding that smaller flower plantings may have higher impacts on small pollinators than larger plantings suggests resource managers interested in pollinator conservation should consider spreading multiple, smaller floral plantings across the urban landscape, rather than pooling all resources into one large flower patch. [ABSTRACT FROM AUTHOR]

Abstract: Genlisea violacea is a Brazilian endemic carnivorous plant species distributed in the cerrado biome, mainly in humid environments, on sandy and oligotrophic soil or wet rocks. Studies on reproductive biology or pollination in the Lentibulariaceae are notably scarce; regarding the genus Genlisea, the current study is the first to show systematic and standardised research on reproductive biology from field studies to describe the foraging of visiting insects and determine the effective pollinators of Genlisea. We studied two populations of G. violacea through the observation of flower visitors for 4 months of the rainy and dry seasons. Stigmatic receptivity, pollen viability, and breeding system were evaluated together with histochemistry and morphological analyses of flowers. The flowers showed stigmatic receptivity of 100% in open buds and mature flowers, reducing to 80% for senescent flowers. Nearly 80% of pollen grains are viable, decreasing to 40–45% after 48 h. Nectar is produced by glandular trichomes inside the spur. Two bee species are effective pollinators: one of the genus Lasioglossum (subgenus Dialictus: Halictidae) and the other of the genus Ceratina (subgenus Ceratinula: family Apidae). Moreover, bee‐like flies of the Syrphidae family may also be additional pollinators. Genlisea violacea is an allogamous and self‐compatible species. The differences in flower‐visiting fauna for both populations can be attributed to factors such as climate, anthropogenic effect, seasonal factors related to insects and plants, as well as the morphological variation of flowers in both populations. [ABSTRACT FROM AUTHOR]

Abstract: Maize is a poorly competitive crop. Accordingly, soil preparation and high application rates of herbicides are required to reduce early competition with weeds. This leaves a large amount of bare ground with few flowering weeds, providing a poor farmland habitat for pollinators. The present study evaluates the effect of four different maize management regimes on pollinator diversity and community composition. Flowering plants intercropped with maize attracted pollinators, helping to support pollinator communities. Similar intercropping techniques using a grass ground cover did not increase pollinator density, demonstrating that pollinator richness, density and diversity is intrinsically linked to the presence of flowering plants. A maize system with a diverse intercrop may make it possible for pollinators to thrive; however, these systems may only be sufficiently attractive to bring pollinators in temporarily from the surrounding areas. These results show that there can be significant improvements to pollinator diversity, density and community composition as a result of modifying maize cultivation practices; however, these benefits must be balanced with yield penalties of approximately 60% to farmers. [ABSTRACT FROM AUTHOR]

Abstract: Systemic neonicotinoid insecticides used in urban arboriculture could pose a risk to bees and other pollinators foraging on treated plants. We measured uptake and dissipation of soil‐applied imidacloprid and dinotefuran in nectar and leaves of 2 woody plant species, a broadleaf evergreen tree (Ilex × attenuata) and a deciduous shrub (Clethra alnifolia), to assess concentrations to which pollinators and pests might be exposed in landscape settings. Three application timings, autumn (postbloom), spring (prebloom), and summer (early postbloom), were evaluated to see if taking advantage of differences in the neonicotinoids’ systemic mobility and persistence might enable pest control while minimizing transference into nectar. Nectar and tissue samples were collected from in‐ground plants and analyzed for residues by high‐performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) in 2 successive years. Concentrations found in nectar following autumn or spring applications ranged from 166 to 515 ng/g for imidacloprid and from 70 to 1235 ng/gg for dinotefuran, depending on plant and timing. These residues exceed concentrations shown to adversely affect individual‐ and colony‐level traits of bees. Summer application mitigated concentrations of imidacloprid (8–31 ng/g), but not dinotefuran (235–1191 ng/g), in nectar. Our data suggest that dinotefuran may be more persistent than is generally believed. Implications for integrated pest and pollinator management in urban landscapes are discussed. Environ Toxicol Chem 2018;37:860–870. © 2017 SETAC [ABSTRACT FROM AUTHOR]

Aim Landscape composition and spatial configuration of habitat patches are important determinants of biodiversity in fragmented semi-natural habitats spread across agricultural landscapes. However, little attention has been paid to man-made structures that can moderate spatial processes affecting pollinator communities. In a large-scale study, we explored the importance of railway embankments for the turnover of pollinator species in agricultural landscapes. Because species differ in vulnerability to landscape composition and patch configuration, we also accounted for body size as well as food specialization of pollinators. Location Kraków area, Poland. Methods We sampled pollinating insects (bees, butterflies and hoverflies), at 25 study sites located along railway lines in the region of Kraków, Poland. Control grasslands for the embankments included 19 patches, located among crop fields, in which pollinators were sampled. We assessed the relationships between dissimilarity and distance for bee, butterfly and hoverfly trait groups on embankments and grasslands using Moran's Eigenvector Maps. Results The dissimilarity for food-non-specialized bees on embankments was spatially structured: sites that were closer together were also less dissimilar in their community composition than more distant ones. Dissimilarity was also spatially aligned for large-bodied butterflies and hoverflies on embankments. The species dissimilarity of pollinators divided into trait-based groups was not spatially structured on grasslands. Main conclusion Our study highlights the potential function of railway embankments as corridors for at least some pollinator populations. Landscape managers should include railways in green networks to improve spatial processes linked with the distribution and turnover of pollinator species in agricultural landscapes. Thus, railway embankments and their correct management may be a good example of man-made alterations in the environment that meet the demands of both civilization and biodiversity conservation. [ABSTRACT FROM AUTHOR]

PREMISE OF THE STUDY: Land-use change is cited as a primary driver of global biodiversity loss, with myriad consequences for species, populations, and ecosystems. However, few studies have examined its impact on species interactions, particularly pollination. Furthermore, when the effects of land-use change on pollination have been studied, the focus has largely been on species pollinated by diurnal pollinators, namely, bees and butterflies. Here, we focus on Oenothera harringtonii, a night-flowering, disturbance-adapted species that has experienced a range-wide gradient of land-use change. We tested the hypothesis that the negative impacts of land-use change are mitigated by long-distance pollination. METHODS: Our study included both temporal (4 yr) and spatial (19 populations range-wide, and 1, 2, and 5 km from the population center) data, providing a comprehensive understanding of the role of land-use change on pollination biology and reproduction. KEY RESULTS: We first confirmed that O. harringtonii is self-incompatible and reliant on pollinators for reproduction. We then showed that hawkmoths (primarily Hyles lineata ) are highly reliable and effective pollinators in both space and time. Unlike other studies, we did not detect an effect of population size, increased isolation, or a reduction in suitable habitat in areas with evidence of land-use change on pollination (visitation, pollen removal and deposition). Furthermore, the proportion of suitable habitat and other fragmentation metrics examined were not associated with population size or density in this plant species. CONCLUSIONS: We conclude that nocturnal pollination of Oenothera harringtonii via hawkmoths is robust to the negative impacts of land-use change. [ABSTRACT FROM AUTHOR]

In 2013, an opportunity arose in England to develop an agri-environment package for wild pollinators, as part of the new Countryside Stewardship scheme launched in 2015. It can be understood as a 'policy window', a rare and time-limited opportunity to change policy, supported by a narrative about pollinator decline and widely supported mitigating actions. An agri-environment package is a bundle of management options that together supply sufficient resources to support a target group of species. This paper documents information that was available at the time to develop such a package for wild pollinators. Four questions needed answering: (1) Which pollinator species should be targeted? (2) Which resources limit these species in farmland? (3) Which management options provide these resources? (4) What area of each option is needed to support populations of the target species? Focussing on wild bees, we provide tentative answers that were used to inform development of the package. There is strong evidence that floral resources can limit wild bee populations, and several sources of evidence identify a set of agri-environment options that provide flowers and other resources for pollinators. The final question could only be answered for floral resources, with a wide range of uncertainty. We show that the areas of some floral resource options in the basic Wild Pollinator and Farmland Wildlife Package (2% flower-rich habitat and 1 km flowering hedgerow), are sufficient to supply a set of six common pollinator species with enough pollen to feed their larvae at lowest estimates, using minimum values for estimated parameters where a range was available. We identify key sources of uncertainty, and stress the importance of keeping the Package flexible, so it can be revised as new evidence emerges about how to achieve the policy aim of supporting pollinators on farmland. [ABSTRACT FROM AUTHOR]

Agriculture now constitutes 40-50% of terrestrial land use globally. By enhancing habitat suitability and connectivity, restoration within agricultural landscapes could have a major influence on biodiversity conservation. However, habitat management within intensive agricultural landscapes may primarily boost abundances of common, highly mobile generalists, rather than vulnerable or endangered species. We studied pollinator community response to small-scale habitat restoration in the intensively farmed Central Valley of California to determine whether restoration could also promote more specialized, less common and/or less mobile species., Composition of pollinator communities was assessed in five experimental and 10 control (unrestored) sites before and after restoration of native plant hedgerows over an 8-year period, using a before-after control-impact design., We characterized bee and fly species based on functional response traits [floral specialization, habitat specialization, abundance, body size and sociality (bees only)] known to influence the response to habitat change., We modelled how species occurrences changed with habitat restoration over time as modulated by their response traits., We found that hedgerows not only significantly enhanced occurrences of native bee and syrphid fly species, but that as hedgerows matured, they had a greater positive effect on species that were more specialized in floral and nesting resources and smaller (less mobile)., Synthesis and applications. Unlike previous studies that suggest habitat restoration in agricultural landscapes only benefits mobile, generalist species, our results suggest that small-scale habitat restoration can promote species whose traits likely render them particularly vulnerable to habitat degradation. Thus, even within highly intensive agricultural landscapes, small-scale habitat restoration can be a conservation management tool. However, tailoring habitat enhancements to promote certain species or guilds may be critical for their success as a conservation intervention in agricultural landscapes. [ABSTRACT FROM AUTHOR]

Neonicotinoids are now the most widely used insecticides in the world. They act systemically, travelling through plant tissues and protecting all parts of the crop, and are widely applied as seed dressings. As neurotoxins with high toxicity to most arthropods, they provide effective pest control and have numerous uses in arable farming and horticulture., However, the prophylactic use of broad-spectrum pesticides goes against the long-established principles of integrated pest management ( IPM), leading to environmental concerns., It has recently emerged that neonicotinoids can persist and accumulate in soils. They are water soluble and prone to leaching into waterways. Being systemic, they are found in nectar and pollen of treated crops. Reported levels in soils, waterways, field margin plants and floral resources overlap substantially with concentrations that are sufficient to control pests in crops, and commonly exceed the LC50 (the concentration which kills 50% of individuals) for beneficial organisms. Concentrations in nectar and pollen in crops are sufficient to impact substantially on colony reproduction in bumblebees., Although vertebrates are less susceptible than arthropods, consumption of small numbers of dressed seeds offers a route to direct mortality in birds and mammals., Synthesis and applications. Major knowledge gaps remain, but current use of neonicotinoids is likely to be impacting on a broad range of non-target taxa including pollinators and soil and aquatic invertebrates and hence threatens a range of ecosystem services. [ABSTRACT FROM AUTHOR]

Dillenia suffruticosa ( Dilleniaceae), a common pioneer shrub in Southeast Asia, is broadly distributed along roadsides. This species flowers throughout the year and is thought to be a keystone species for maintaining populations of flower visitors. To examine the flower visitors of this species, we conducted field surveys and described the behaviors of each flower visitor species within four different research sites: Primary Forests 1 and 2, Secondary Forest, and Mixed Vegetation. We caught 1087 individuals belonging to 51 species from 11 insect families and one species of arachnid. Most flower visitors belonged to Hymenoptera (98.6% of individuals); Trigona spp. and Xylocopa spp. ( Apidae) accounted for 64.0% and 20.0%, respectively, of all caught individuals. According to observations of behavior by each species, effective pollinators may include Xylocopa spp. and Amegilla spp. ( Apidae). We compared the research results among four research sites and found that the effective pollinators were not different among sites. However, the number of species and the abundances of flower visitors decreased in disturbed areas, especially in Secondary Forest. This research suggests the effects of human disturbances on the diversity and abundance of flower visitors. [ABSTRACT FROM AUTHOR]

The fat body (FB) consists of two types of cells: throphocytes and oenocytes. Throphocytes are related to intermediary metabolism storing lipids, carbohydrates, and proteins while oenocytes play role in the lipids and lipoproteins production. The vitellogenin is the precursor of egg yolk (vitelline) and is synthesized on FB. The aim of this work was to analyze the effects of hormones acting in bee reproduction, as juvenile hormone (JH) and ecdisteroids (20 HE) on FB cells, where vitellogenin is synthesized. For the study were chose nurse workers that in Melipona quadrifasciata anthidioides present activated ovaries and produce eggs, and virgin queens whose ovaries are not yet activated, presenting only previtellogenic follicles. FB trophocytes from these classes of bees were cultivated in media containing different amounts of JH and 20-HE. The effects on trophocytes cytoplasm reserves of lipids, proteins, and activity of acid phosphatase were compared by observing preparations from cultured FB, treated and control, by transmission electron microscopy (TEM). The results showed that the hormones effects are related to the bee's caste and functional ovary stage. The role of acid phosphatase on mobilization of the trophocyte reserves was also determined. Microsc. Res. Tech. 2013. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Concerns about pollinator declines have grown in recent years, yet the ability to detect changes in abundance, taxonomic richness, and composition of pollinator communities is hampered severely by the lack of data over space and time. Citizen scientists may be able to extend the spatial and temporal extent of pollinator monitoring programs. We developed a citizen-science monitoring protocol in which we trained 13 citizen scientists to observe and classify floral visitors at the resolution of orders or super families (e.g., bee, wasp, fly) and at finer resolution within bees (superfamily Apoidea ) only. We evaluated the protocol by comparing data collected simultaneously at 17 sites by citizen scientists (observational data set) and by professionals (specimen-based data set). The sites differed with respect to the presence and age of hedgerows planted to improve habitat quality for pollinators. We found significant, positive correlations among the two data sets for higher level taxonomic composition, honey bee (Apis mellifera ) abundance, non-Apis bee abundance, bee richness, and bee community similarity. Results for both data sets also showed similar trends (or lack thereof) in these metrics among sites differing in the presence and age of hedgerows. Nevertheless, citizen scientists did not observe approximately half of the bee groups collected by professional scientists at the same sites. Thus, the utility of citizen-science observational data may be restricted to detection of community-level changes in abundance, richness, or similarity over space and time, and citizen-science observations may not reliably reflect the abundance or frequency of occurrence of specific pollinator species or groups. [ABSTRACT FROM AUTHOR]

Measuring species richness of tropical insects is an important but considerable challenge. Several techniques have been developed to quantitatively sample the non-formicid Hymenoptera (bees and wasps). One of the most common is the use of colored pan traps. Although it is known that Hymenoptera are attracted differently by different colors, it is not yet known if these preferences shift in different habitats and hence affect comparisons of Hymenoptera diversity. We studied the effectiveness of differently-colored pan traps along a latitudinal, climatic, and forest structure gradient from tropical to subtropical forests. Overall, we found a strong increase in individual numbers from north to south. Yellow traps sampled significantly more individuals than blue ones, mainly due to the responses of the families Ichneumonidae, Nyssonidae, Pompilidae, and Crabronidae, but trap catch was also related to canopy cover. Notably, traps located at forest edges had yellow/blue ratios similar to those of forests with comparable canopy cover. This suggests that, in contrast to the overall number of individuals caught, the relative effectiveness of yellow vs. blue traps was driven by canopy cover and hence light conditions or visibility of the traps. Thus comparisons of pan trap results between forests having different structures should only be made with great care. [ABSTRACT FROM AUTHOR]

Despite a long-standing belief that insect pollinators can select for certain flower colors, there are few experimental demonstrations that free-flying insects choose between natural flowers based on color. We investigated responses of insect visitors to experimental manipulations of flower color in the New Zealand alpine. Native syrphid flies (Allograpta and Platycheirus) and solitary bees (Hylaeus and Leioproctus) showed distinct preferences for visiting certain flower species. These responses were determined, in part, by flower color, as insects also responded to experimental manipulations of visible petal color in 7 out of 11 tests with different combinations of flower species and insect type. When preferences were detected, syrphid flies chose yellow over white petals regardless of flower species, whereas Hylaeus chose white over yellow Ourisia giandulosa. In some cases, the strength and direction of color preference depended on the context of other floral traits, in which case the response usually favored the familiar, normal combination of traits. Syrphid flies also visited in response to floral morphological traits but did not show preference based on UV reflectance. The unusually high preponderance of white flowers in the New Zealand alpine is not explained by complete generalization of flower color choice. Instead, the insect visitors show preferences based on color, including colors other than white, along with other floral traits. Furthermore, they can respond in complex ways to combinations of floral cues, suggesting that traits may act in nonadditive ways in determining pollinator visitation. [ABSTRACT FROM AUTHOR]

Microbial pathogens were important in the evolution of insect societies and remain a major cause of colony death. The differential effects are reported of antimicrobial compounds extracted from six species of Australian native bees on the spores and hyphae of the entomopathogenic fungus Cordyceps bassiana. The bee species were: Amegilla bombiformis, A. asserta, Exoneura robusta, E. nigrescens, Exoneurella tridentata and Trigona carbonaria. The fungus was isolated from E. robusta and it was this species that showed the greatest activity against both Cordyceps spore germination and hyphal growth. One explanation is that anti- Cordyceps activity may have been under greatest selection in this bee species, but its congener, E. nigrescens, showed only slightly weaker activity against the pathogen. In contrast, A. bombiformis, A. asserta, E. tridentata and T. carbonaria showed considerable variation in anti- Cordyceps activity. Nevertheless, there was a trend of greater activity against Cordyceps spore germination than hyphal growth. On the basis of this result, a mechanism whereby fungal pathogens may have been important drivers of social evolution is suggested. [ABSTRACT FROM AUTHOR]

Natural vegetation is often replaced by invasive alien plants on isolated oceanic islands. To determine how invasive alien plants affect insect diversity, we compared flying insects captured using Malaise traps among different vegetation types on a small island (Nishijima; 0.49 km2) in the oceanic Ogasawara (Bonin) Islands in the north-western Pacific. The numbers of individuals and species, and the species composition of pollinators (bees), predators (wasps) and wood borers (cerambycid, mordellid and elaterid beetles) were compared among three vegetation types: Casuarina equisetifolia (an invasive alien tree) forest, natural forest and natural grassland (forest edge), during two seasons (June and October–November 2005). In traps, 80.0, 66.7, 87.5, 85.7 and 100.0% of bee, wasp, cerambycid, mordellid and elaterid beetle species, respectively, were endemic to the Ogasawara Islands. Grassland had the highest wasp and bee species richness, whereas natural forest had the highest species richness of wood-boring beetles. The C. equisetifolia forest had the poorest species richness for most insect groups (except mordellid beetles). More individuals of most insect groups (except bees) were captured in June than in October–November. More individual bees and wasps were captured in grassland than in forests, whereas more individual mordellid and elaterid beetles were captured in forests than in grassland. The number of cerambycid individuals did not differ among vegetation types. Redundancy analysis suggested that most insect species preferred natural forest or grassland to alien forest. Therefore, further invasion of natural grassland and forest by the alien tree C. equisetifolia may negatively affect the endemic insect fauna of Nishijima. [ABSTRACT FROM AUTHOR]

To evaluate the role that a trap-nest cover might have on sampling methodologies, the abundance of each species of trap-nesting Hymenoptera and the parasitism rate in a Canadian forest were compared between artificially covered and uncovered traps. Of trap tubes exposed at eight forest sites in six trap-nest boxes, 531 trap tubes were occupied and 1216 individuals of 12 wasp species of four predatory families, Vespidae (Eumeninae), Crabronidae, Sphecidae and Pompilidae emerged over 2 years, and no bee species were found. Results indicated that artificial covering led to a significant increase in the number of nested tubes of Ancistrocerus adiabatus, Ancistrocerus antilope, Ancistrocerus campestris and Auplopus mellipes, and significant effects of covering were not found for the other species. No significant difference in the overall parasitism rate between covered and uncovered traps was noted. These suggested that the covering technique could provide more opportunities for some wasp species to colonize trap nests. [ABSTRACT FROM AUTHOR]

Global biodiversity decline has prompted great interest in the effects of habitat modification and diversity on the functioning and stability of ecosystem processes. However, the applicability of previous modeled or mesocosm community studies to real diverse communities in different habitats remains ambiguous. We exposed standardized nesting resources for naturally occurring communities of cavity-nesting bees and wasps and their parasitoids in coastal Ecuador, to test the effects of host and parasitoid diversity on an ecosystem function (parasitism rates) and temporal variability in this function. In accordance with predictions of complementary host use, parasitism rates increased with increasing diversity, not simply abundance, of parasitoids. In contrast, parasitism decreased with increasing host diversity, possibly due to positive prey interactions or increased probability of selecting unpalatable species. Temporal variability in parasitism was lower in plots with high mean parasitoid diversity and higher in plots with temporally variable host and parasitoid diversity. These effects of diversity on parasitism and temporal stability in parasitism rates were sufficiently strong to be visible across five different habitat types, representing a gradient of increasing anthropogenic modification. Habitat type did not directly affect parasitism rates, but host and parasitoid diversity and abundance were higher in highly modified habitats, and parasitoid diversity was positively correlated with rates of parasitism. The slope of the richness-parasitism relationship did not vary significantly across habitats, although that for Simpson's diversity was significant only in rice and pasture. We also show that pooling data over long time periods, as in previous studies, can blur the effect of diversity on parasitism rates, and the appropriate spatiotemporal scale of study must be considered. [ABSTRACT FROM AUTHOR]