Pesticide use negatively affects bumble bees across European landscapes.

Sustainable agriculture requires balancing crop yields with the effects of pesticides on non-target organisms, such as bees and other crop pollinators. Field studies demonstrated that agricultural use of neonicotinoid insecticides can negatively affect wild bee species1,2, leading to restrictions on these compounds3. However, besides neonicotinoids, field-based evidence of the effects of landscape pesticide exposure on wild bees is lacking. Bees encounter many pesticides in agricultural landscapes4-9 and the effects of this landscape exposure on colony growth and development of any bee species remains unknown. Here we show that the many pesticides found in bumble bee-collected pollen are associated with reduced colony performance during crop bloom, especially in simplified landscapes with intensive agricultural practices. Our results from 316 Bombus terrestris colonies at 106 agricultural sites across eight European countries confirm that the regulatory system fails to sufficiently prevent pesticide-related impacts on non-target organisms, even for a eusocial pollinator species in which colony size may buffer against such impacts10,11. These findings support the need for postapproval monitoring of both pesticide exposure and effects to confirm that the regulatory process is sufficiently protective in limiting the collateral environmental damage of agricultural pesticide use.

Bursty spike trains of antennal thermo- and bimodal hygro-thermoreceptor neurons encode noxious heat in elaterid beetles.

The main purpose of this study was to explain the internal fine structure of potential antennal thermo- and hygroreceptive sensilla, their innervation specifics, and responses of the sensory neurons to thermal and humidity stimuli in an elaterid beetle using focused ion beam scanning electron microscopy and electrophysiology, respectively. Several essential, high temperature induced turning points in the locomotion were determined using automated video tracking. Our results showed that the sensilla under study, morphologically, are identical to the dome-shaped sensilla (DSS) of carabids. A cold-hot neuron and two bimodal hygro-thermoreceptor neurons, the moist-hot and dry-hot neuron, innervate them. Above 25-30 °C, all the three neurons, at different threshold temperatures, switch from regular spiking to temperature dependent spike bursting. The percentage of bursty DSS neurons on the antenna increases with temperature increase suggesting that this parameter of the neurons may encode noxious heat in a graded manner. Thus, we show that besides carabid beetles, elaterids are another large group of insects with this ability. The threshold temperature of the beetles for onset of elevated locomotor activity (OELA) was lower by 11.9 °C compared to that of critical thermal maximum (39.4 °C). Total paralysis occurred at 41.8 °C. The threshold temperatures for spike bursting of the sensory neurons in DSS and OELA of the beetles coincide suggesting that probably the spike bursts are responsible for encoding noxious heat when confronted. In behavioural thermoregulation, spike bursting DSS neurons serve as a fast and firm three-fold early warning system for the beetles to avoid overheating and death.

Metabolic rate associates with, but does not generate covariation between, behaviours in western stutter-trilling crickets, Gryllus integer.

The causes and consequences of among-individual variation and covariation in behaviours are of substantial interest to behavioural ecology, but the proximate mechanisms underpinning this (co)variation are still unclear. Previous research suggests metabolic rate as a potential proximate mechanism to explain behavioural covariation. We measured the resting metabolic rate (RMR), boldness and exploration in western stutter-trilling crickets, Gryllus integer, selected differentially for short and fast development over two generations. After applying mixed-effects models to reveal the sign of the covariation, we applied structural equation models to an individual-level covariance matrix to examine whether the RMR generates covariation between the measured behaviours. All traits showed among-individual variation and covariation: RMR and boldness were positively correlated, RMR and exploration were negatively correlated, and boldness and exploration were negatively correlated. However, the RMR was not a causal factor generating covariation between boldness and exploration. Instead, the covariation between all three traits was explained by another, unmeasured mechanism. The selection lines differed from each other in all measured traits and significantly affected the covariance matrix structure between the traits, suggesting that there is a genetic component in the trait integration. Our results emphasize that interpretations made solely from the correlation matrix might be misleading.

The opening-closing rhythms of the subelytral cavity associated with gas exchange patterns in diapausing Colorado potato beetle, Leptinotarsa decemlineata.

The opening-closing rhythms of the subelytral cavity and associated gas exchange patterns were monitored in diapausing Leptinotarsa decemlineata beetles. Measurements were made by means of a flow-through CO2 analyser and a coulometric respirometer. Under the elytra of these beetles there is a more or less tightly enclosed space, the subelytral cavity (SEC). When the cavity was tightly closed, air pressure inside was sub-atmospheric, as a result of oxygen uptake into the tracheae by the beetle. In about half of the beetles, regular opening-closing rhythms of the SEC were observed visually and also recorded; these beetles displayed a discontinuous gas exchange pattern. The SEC opened at the start of the CO2 burst and was immediately closed. On opening, a rapid passive suction inflow of atmospheric air into the SEC occurred, recorded coulometrically as a sharp upward peak. As the CO2 burst lasted beyond the closure of the SEC, we suggest that most of the CO2 was expelled through the mesothoracic spiracles. In the remaining beetles, the SEC was continually semi-open, and cyclic gas exchange was exhibited. The locking mechanisms and structures between the elytra and between the elytra and the body were examined under a stereomicroscope and by means of microphotography. We conclude that at least some of the L. decemlineata diapausing beetles were able to close their subelytral cavity tightly, and that the cavity then served as a water-saving device.

Resource availability as a proxy for terminal investment in a beetle.

Terminal investment hypothesis is a longstanding theoretical idea that organisms should increase their reproductive effort as their prospects for survival and reproduction decline. However, numerous attempts to test the terminal investment in reproduction have yielded contradictory results. This study reports an experimental confirmation of the terminal investment hypothesis. It was predicted that immune-challenged yellow mealworm beetles (Tenebrio molitor) are more likely to follow terminal investment strategy when their food resources are limited. Our results suggest the key role of food resources while making decisions to follow a terminal investment strategy. We found that male individuals invested in their sexual attractiveness at the expense of immune response and survival when food was not available. In contrast, the beetles did not decrease their lifespan and did not invest in the attractiveness of their sex odours under conditions of food ad libitum. Our results show the importance of food availability and quality in understanding the evolution of reproductive strategies.

Distribution of infectious and parasitic agents among three sentinel bee species across European agricultural landscapes.

Infectious and parasitic agents (IPAs) and their associated diseases are major environmental stressors that jeopardize bee health, both alone and in interaction with other stressors. Their impact on pollinator communities can be assessed by studying multiple sentinel bee species. Here, we analysed the field exposure of three sentinel managed bee species (Apis mellifera, Bombus terrestris and Osmia bicornis) to 11 IPAs (six RNA viruses, two bacteria, three microsporidia). The sentinel bees were deployed at 128 sites in eight European countries adjacent to either oilseed rape fields or apple orchards during crop bloom. Adult bees of each species were sampled before their placement and after crop bloom. The IPAs were detected and quantified using a harmonised, high-throughput and semi-automatized qPCR workflow. We describe differences among bee species in IPA profiles (richness, diversity, detection frequencies, loads and their change upon field exposure, and exposure risk), with no clear patterns related to the country or focal crop. Our results suggest that the most frequent IPAs in adult bees are more appropriate for assessing the bees' IPA exposure risk. We also report positive correlations of IPA loads supporting the potential IPA transmission among sentinels, suggesting careful consideration should be taken when introducing managed pollinators in ecologically sensitive environments.

Novel indices reveal that pollinator exposure to pesticides varies across biological compartments and crop surroundings.

Declines in insect pollinators have been linked to a range of causative factors such as disease, loss of habitats, the quality and availability of food, and exposure to pesticides. Here, we analysed an extensive dataset generated from pesticide screening of foraging insects, pollen-nectar stores/beebread, pollen and ingested nectar across three species of bees collected at 128 European sites set in two types of crop. In this paper, we aimed to (i) derive a new index to summarise key aspects of complex pesticide exposure data and (ii) understand the links between pesticide exposures depicted by the different matrices, bee species and apple orchards versus oilseed rape crops. We found that summary indices were highly correlated with the number of pesticides detected in the related matrix but not with which pesticides were present. Matrices collected from apple orchards generally contained a higher number of pesticides (7.6 pesticides per site) than matrices from sites collected from oilseed rape crops (3.5 pesticides), with fungicides being highly represented in apple crops. A greater number of pesticides were found in pollen-nectar stores/beebread and pollen matrices compared with nectar and bee body matrices. Our results show that for a complete assessment of pollinator pesticide exposure, it is necessary to consider several different exposure routes and multiple species of bees across different agricultural systems.

Intra-specific variation in sensitivity of Bombus terrestris and Osmia bicornis to three pesticides.

There is growing evidence that pesticides may be among the causes of worldwide bee declines, which has resulted in repeated calls for their increased scrutiny in regulatory assessments. One recurring concern is that the current frameworks may be biased towards assessing risks to the honey bee. This paradigm requires extrapolating toxicity information across bee species. Most research effort has therefore focused on quantifying differences in sensitivity across species. However, our understanding of how responses to pesticides may vary within a species is still very poor. Here we take the first steps towards filling this knowledge gap by comparing acute, lethal hazards in sexes and castes of the eusocial bee Bombus terrestris and in sexes of the solitary bee Osmia bicornis after oral and contact exposure to the pesticides sulfoxaflor, Amistar (azoxystrobin) and glyphosate. We show that sensitivity towards pesticides varies significantly both within and across species. Bee weight was a meaningful predictor of pesticide susceptibility. However, weight could not fully explain the observed differences, which suggests the existence of unexplored mechanisms regulating pesticide sensitivity across bee sexes and castes. Our data show that intra-specific responses are an overlooked yet important aspect of the risk assessment of pesticides in bees.

Honey bees and climate explain viral prevalence in wild bee communities on a continental scale.

Viruses are omnipresent, yet the knowledge on drivers of viral prevalence in wild host populations is often limited. Biotic factors, such as sympatric managed host species, as well as abiotic factors, such as climatic variables, are likely to impact viral prevalence. Managed and wild bees, which harbor several multi-host viruses with a mostly fecal-oral between-species transmission route, provide an excellent system with which to test for the impact of biotic and abiotic factors on viral prevalence in wild host populations. Here we show on a continental scale that the prevalence of three broad host viruses: the AKI-complex (Acute bee paralysis virus, Kashmir bee virus and Israeli acute paralysis virus), Deformed wing virus, and Slow bee paralysis virus in wild bee populations (bumble bees and solitary bees) is positively related to viral prevalence of sympatric honey bees as well as being impacted by climatic variables. The former highlights the need for good beekeeping practices, including Varroa destructor management to reduce honey bee viral infection and hive placement. Furthermore, we found that viral prevalence in wild bees is at its lowest at the extreme ends of both temperature and precipitation ranges. Under predicted climate change, the frequency of extremes in precipitation and temperature will continue to increase and may hence impact viral prevalence in wild bee communities.

Oxygen convective uptakes in gas exchange cycles in early diapause pupae of Pieris brassicae.

Oxygen convective uptakes in gas exchange cycles were directly recorded in early diapause pupae of Pieris brassicae L. (Lepidoptera; Pieridae) by means of O2 coulometric respirometry. This method was combined with flow-through CO2 respirometry, the two systems being switchable one to the other. During recording with both systems, measurements were also taken with infrared actography. The pupae displayed short discontinuous gas exchange cycles lasting 40-70 min. No true C phase was found by flow-through measurements; instead, flutter opening of the spiracles with discrete convective O2 uptakes began shortly after the O phase whereas CO2 release was suppressed by the inward directed passive suction ventilation. The F phase was characterized by a series of small CO2 bursts (flutter events). Between these bursts, novel sub-phase `miniflutter' was observed, which consisted of six to 10 miniature inspirations without any CO2 emission. During the flow-through measurements, oxygen convective uptakes were indirectly recorded by the infrared actograph as sudden extensions (lengthening) of the abdominal segments at each spiracular microopening.

Bumble Bee Foraged Pollen Analyses in Spring Time in Southern Estonia Shows Abundant Food Sources.

Agricultural landscapes usually provide higher quantities of single-source food, which are noticeably lacking in diversity and might thus have low nutrient value for bumble bee colony development. Here, in this study, we analysed the pollen foraging preferences over a large territory of a heterogeneous agricultural landscape: southern Estonia. We aimed to assess the botanical diversity of bumble bee food plants in the spring time there. We looked for preferences for some food plants or signs of food shortage that could be associated with any particular landscape features. For this purpose, we took Bombus terrestris commercial hives to the landscape, performed microscopy analyses and improved the results with the innovative DNA metabarcoding technique to determine the botanical origin of bumble bee-collected pollen. We found high variability of forage plants with no strong relationship with any particular landscape features. Based on the low number of plant species in single flights, we deduce that the availability of main forage plants is sufficient indicating rich forage availabilities. Despite specific limitations, we saw strong correlations between microscopy and DNA metabarcoding data usable for quantification analyses. As a conclusion, we saw that the spring-time vegetation in southern Estonia can support bumble bee colony development regardless of the detailed landscape structure. The absence of clearly dominating food preference by the tested generalist bumble bee species B. terrestris makes us suggest that other bumble bee species, at least food generalists, should also find plenty of forage in their early development phase.

Translocation of Tebuconazole between Bee Matrices and Its Potential Threat on Honey Bee (Apis mellifera Linnaeus) Queens.

Various pesticide residues can be found in different bee colony components. The queen larvae of honey bee (Apis mellifera L.) receive non-contaminated food from nurse bees. However, there is little knowledge about how pesticide residues affect developing bees. Additionally, little is known about the migration of lipophilic pesticides between bee matrices. While wax, royal jelly (RJ), and bee larvae are chemically distinct, they all contain lipids and we expected the lipophilic fungicide tebuconazole to be absorbed by different contacting materials. Our aim was to analyze the translocation of tebuconazole residues from queen cell wax to RJ, queen larvae, and newly emerged queens and to evaluate its potential risk to queens. We demonstrated the potential for the migration of tebuconazole from wax to RJ, with a strong dilution effect from the original contamination source. No residues were detected in queen bee larvae and newly emerged queens, indicating that the migration of tebuconazole probably did not directly endanger the queen bee, but there was some risk that tebuconazole might still affect the homeostasis of developing bees.

Green Leaf Volatile Confers Management of Late Blight Disease: A Green Vaccination in Potato.

Yield losses of crops due to plant pathogens are a major threat in all agricultural systems. In view of environmental issues and legislative limitations for chemical crop protection products, the need to design new environmentally friendly disease management strategies has gained interest. Despite the unique capability of green leaf volatiles (GLVs) to suppress a broad spectrum of plant pathogens, their capacity to control the potato late-blight-causing agent Phytophthora infestans has not been well studied. This study addresses the potential role of the GLV Z-3-hexenyl acetate (Z-3-HAC) in decreasing the severity of late blight and the underlying gene-based evidence leading to this effect. Nine-week-old potato plants (Solanum tuberosum L.) were exposed to Z-3-HAC before they were inoculated with P. infestans genotypes at different time points. These pre-exposed potato plants exhibited slower disease development after infection with the highly pathogenic genotype of P. infestans (EU-13-A2) over time. Qualitative assessment showed that the exposed, infected plants possessed significantly lower sporulation intensity and disease severity compared to the control plants. Hypersensitive response (HR)-like symptoms were observed on the treated leaves when inoculated with different pathogen genotypes. No HR-like lesions were detected on the untreated leaves after infection. It was shown that the transcript levels of several defense-related genes, especially those that are involved in reactive oxygen species (ROS) production pathways were significantly expressed in plants at 48 and 72 h postexposure to the Z-3-HAC. The current work provides evidence on the role of Z-3-HAC in the increased protection of potato plants against late blight through plant immunity and offers new opportunities for the sustainable control of potato diseases.

Neural Code for Ambient Heat Detection in Elaterid Beetles.

Environmental thermal conditions play a major role at all levels of biological organization; however, there is little information on noxious high temperature sensation crucial in behavioral thermoregulation and survival of small ectothermic animals such as insects. So far, a capability to unambiguously encode heat has been demonstrated only for the sensory triad of the spike bursting thermo- and two bimodal hygro-thermoreceptor neurons located in the antennal dome-shaped sensilla (DSS) in a carabid beetle. We used extracellular single sensillum recording in the range of 20-45°C to demonstrate that a similar sensory triad in the elaterid Agriotes obscurus also produces high temperature-induced bursty spike trains. Several parameters of the bursts are temperature dependent, allowing the neurons in a certain order to encode different, but partly overlapping ranges of heat up to lethal levels in a graded manner. ISI in a burst is the most useful parameter out of six. Our findings consider spike bursting as a general, fundamental quality of the classical sensory triad of antennal thermo- and hygro-thermoreceptor neurons widespread in many insect groups, being a flexible and reliable mode of coding unfavorably high temperatures. The possible involvement of spike bursting in behavioral thermoregulation of the beetles is discussed. By contrast, the mean firing rate of the neurons in regular and bursty spike trains combined does not carry useful thermal information at the high end of noxious heat.

Potential of Colorado Potato Beetle (Coleoptera: Chrysomelidae) to Adapt to Alternative Host Plants.

Twelve selected cultivated or wild solanaceae (Solanum dulcamara, Solanum nigrum, Solanum villosum, Solanum lycopersicum, Solanum muricatum, Solanum melongena, Datura innoxia, Datura metel, Physalis spp., Capsicum annuum, Nicotiana alata, and Petunia spp.) (all species Solanales: Solanaceae) were tested as potential alternative host plants against Solanum tuberosum for a local population of the Colorado potato beetle Leptinotarsa decemlineata Say (CPB) in Estonia. Some CPB populations in America and southern Europe accept most of these plants. However, geographically isolated populations of beetles can differ in their acceptance of new host plants. Migrants from the southern Europe supplement Estonian beetle population regularly, so individuals may differ in their host plant preferences. S. melongena and S. dulcamara were well accepted by the beetles, Lycopersicum spp. (Solanales: Solanaceae) and N. alata were intermediate, and S. villosum and S. nigrum were least accepted. The beetles rejected S. muricatum, Physalis spp., C. annuum, Petunia spp., and D. metel. First-instar larvae completed a full life cycle only on S. dulcamara, N. alata, S. lycopesicum, S. melongena, although their development rate was slower, mortality was higher and emerging adults were underweight relative to those that fed on S. tuberosum. The fourth-instar larvae were less sensitive in relation to food. We found that S. dulcamara as a native plant could provide resources for CPB during early and late season. At the same time, the cultivated S. melongena would be suitable plant species for further testing as dead-end crop for integrated pest management.

Pesticide residues in beehive matrices are dependent on collection time and matrix type but independent of proportion of foraged oilseed rape and agricultural land in foraging territory.

Pesticide residues in bee products is still a major issue. However, the relations to botanical source and land use characteristics are not clear. The large variability of residues detected questions the suitability of bee-collected- and other hive materials as indicators for environmental contamination. The aim of our study was to clarify whether different beehive matrices contain similar pesticide residues, and how these are correlated with forage preferences and land use types in foraging areas. We tested bee-collected pollen, beebread, honey, nurse bees and honey bee larvae for the presence of concurrently used agricultural pesticides in Estonia. Samples were collected at the end of May and mid-July to include the main crop in northern region - winter and spring oilseed rape (Brassica napus). We saw that different beehive matrices contained various types of pesticide residues in different proportions: pollen and beebread tended to contain more insecticides and fungicides, whereas herbicides represented the primary contaminant in honey. The variations were related to collection year and time but were not related to crops as basic forage resource nor the land use type. We found few positive correlations between amount of pesticides and proportion of pollen from any particular plant family. None of these correlations were related to any land-use type. We conclude that pesticide residues in different honey bee colony components vary largely in amount and composition. The occurrence rate of pesticide residues was not linked to any particular crop.

Pattern of population structuring between Belgian and Estonian bumblebees.

Several population genetic studies investigated the extent of gene flow and population connectivity in bumblebees. In general, no restriction in gene flow is considered for mainland populations of common bumblebee species. Whether this assumption holds true for all species is not known. An assessment of bumblebee genetic structure in the context of their geographic distribution is needed to prioritize conservation and management needs. Here, we conducted a genetic study on seven bumblebee species occurring in Belgium and Estonia. Using 16 microsatellite markers, we investigated genetic diversity and population structuring in each species. This is the first study investigating population structuring of both declining and stable bumblebee species on both small and large geographic scales. Our results showed no or only low population structuring between the populations of the restricted and declining bumblebee species on both scales, while significant structuring was found for populations of the common species on the larger scale. The latter result, which may be due to human or environmental changes in the landscape, implies the need for the conservation of also widespread bumblebee species. Conservation strategies to improve gene flow and connectivity of populations could avoid the isolation and future losses of populations of these important species.

Level of Genetic Diversity in European Bumblebees is Not Determined by Local Species Abundance.

Bumblebee species with declining population trends tend to show lower genetic diversity levels than stable species. The observed difference might be explained by abundance differences, with declining bumblebee species having lower genetic diversity levels simply due to their lower local species abundances. However, whether this holds true is not known. Here, we investigated whether bumblebee local abundances determines population genetic diversity levels. Therefore, local species abundances were measured for bumblebee species at four locations in Belgium and two locations in Estonia during bumblebee foraging years 2013-2017. These locations and countries were chosen to ensure the greatest possible variance in both local abundances and population trends for these species. Hence, genetic diversity levels were obtained for seven species by genotyping collected specimens with 16 microsatellites. Our results showed that the observed patterns in genetic diversity did not depend on local species abundance. So, although declining bumblebee species can become locally abundant, they will still show lower genetic diversity levels than stable species. This result implies that measuring bumblebees' local abundance cannot be used to directly determine the health status of a population. Furthermore, this result has also major impact on future conservation strategies as increasing the genetic diversity levels of declining species will be very difficult, and habitat quality should be high to maintain their populations, otherwise these species are doomed to disappear first.

Electrophysiological responses from neurons of antennal taste sensilla in the polyphagous predatory ground beetle Pterostichus oblongopunctatus (Fabricius 1787) to plant sugars and amino acids.

The responses of antennal contact chemoreceptors, in the polyphagous predatory ground beetle Pterostichus oblongopunctatus, to twelve 1-1,000 mmol l(-1) plant sugars and seven 10-100 mmol l(-1) amino acids were tested. The disaccharides with an alpha-1.4-glycoside linkage, sucrose and maltose, were the two most stimulatory sugars for the sugar-sensitive neuron innervating these contact chemosensilla. The firing rates they evoked were concentration dependent and reached up to 70 impulses/s at 1,000 mmol l(-1). The stimulatory effect of glucose on this neuron was approximately two times lower. This can be partly explained by the fact that glucose exists in at least two anomeric forms, alpha and beta. These two forms interconvert over a timescale of hours in aqueous solution, to a final stable ratio of alpha:beta 36:64, in a process called mutarotation. So the physiologically active alpha-anomere forms only 36% of the glucose solution which was reflected in its relatively low dose/response curve. Due to the partial herbivory of P. oblongopunctatus these plant sugars are probably involved in its search for food, for example, for conifer seeds. Several carbohydrates, in addition to glucose, such as cellobiose, arabinose, xylose, mannose, rhamnose and galactose are known as components of cellulose and hemicelluloses. They are released by brown-rot fungi during enzymatic wood decay. None of them stimulated the antennal sugar-sensitive neuron. They are therefore not implicated in the search for hibernation sites, which include rotting wood, by this beetle. The weak stimulating effect (below 3 impulses/s) of some 100 mmol l(-1) amino acids (methionine, serine, alanine, glutamine) to the 4th chemosensory neuron of these sensilla was characterized as non-specific, or modulating the responses of non-target chemosensory neurons.

Synergistic interactions between a variety of insecticides and an ergosterol biosynthesis inhibitor fungicide in dietary exposures of bumble bees (Bombus terrestris L.).

BACKGROUND: In recent years, concern has been raised over honey bee colony losses, and also among wild bees there is evidence for extinctions and range contractions in Europe and North America. Pesticides have been proposed as a potential cause of this decline. Bees are exposed simultaneously to a variety of agrochemicals, which may cause synergistically detrimental impacts, which are incompletely understood. We investigated the toxicity of the fungicide imazalil in mixture with four common insecticides: fipronil (phenylpyrazoid), cypermethrin (pyrethroid), thiamethoxam, and imidacloprid (neonicotinoids). Ergosterol biosynthesis inhibitor (EBI) fungicides like imazalil can inhibit P450 detoxification systems in insects and therefore fungicide - insecticide co-occurrence might produce synergistic toxicity in bees. We assessed the impact of dietary fungicide - insecticide mixtures on the mortality and feeding rates of laboratory bumble bees (Bombus terrestris L.). RESULTS: Regarding mortality, imazalil synergised the toxicity of fipronil, cypermethrin and thiamethoxam, but not imidacloprid. We found no synergistic effects on feeding rates. CONCLUSION: Our findings suggest that P450-based detoxification processes are differentially important in mitigating the toxicity of certain insecticides, even those of the same chemical class. Our evidence that cocktail effects can arise in bumble bees should extend concern about the potential impacts of agrochemical mixtures to include wild bee species in farmland. © 2017 Society of Chemical Industry.