Impacts of soil nutrition on floral traits, pollinator attraction, and fitness in cucumbers (Cucumis sativus L.).

Annual plants allocate soil nutrients to floral display and pollinator rewards to ensure pollination success in a single season. Nitrogen and phosphorus are critical soil nutrients whose levels are altered by intensive land use that may affect plants' fitness via pollinator attractiveness through floral display and rewards. In a controlled greenhouse study, we studied in cucumbers (Cucumis sativus) how changes in soil nitrogen and phosphorus influence floral traits, including nectar and pollen reward composition. We evaluated how these traits affect bumble bee (Bombus impatiens, an important cucumber pollinator) visitation and ultimately fruit yield. While increasing nitrogen and phosphorus increased growth and floral display, excess nitrogen created an asymptotic or negative effect, which was mitigated by increasing phosphorus. Male floral traits exhibited higher plasticity in responses to changes in soil nutrients than female flowers. At 4:1 nitrogen:phosphorus ratios, male flowers presented increased nectar volume and pollen number resulting in increased bumble bee visitation. Interestingly, other pollinator rewards remained consistent across all soil treatments: male and female nectar sugar composition, female nectar volume, and pollen protein and lipid concentrations. Therefore, although cucumber pollination success was buffered in conditions of nutrient stress, highly skewed nitrogen:phosphorus soil ratios reduced plant fitness via reduced numbers of flowers and reward quantity, pollinator attraction, and ultimately yield.

Soil moisture affects plant-pollinator interactions in an annual flowering plant.

Many environmental factors impact plant and pollinator communities. However, variation in soil moisture and how it mediates the plant-pollinator interactions has yet to be elucidated. We hypothesized that long-term variation in soil moisture can exert a strong selective pressure on the floral and vegetative traits of plants, leading to changes in pollinator visitation. We demonstrated that there are three phenotypic populations of Gentiana aristata in our study alpine region in the Qinghai-Tibetan Plateau that vary in floral colour and other traits. Pink (dry habitat) and blue (intermediate habitat) flower populations are visited primarily by bumblebees, and white (wet habitat) flower populations are visited by flies. These patterns of visitation are driven by vegetative and floral traits and are constant when non-endemic plants are placed in the intermediate habitats. Additionally, the floral communities in different habitats vary, with more insect-pollinated forbs in the dry and intermediate habitats versus the wet habitats. Through a common garden and reciprocal transplant experiment, we demonstrated that plant growth traits, pollinator attractiveness and seed production are highest when the plant population is raised in its endemic habitat. This suggests that these plant populations have evolved to pollinator communities associated with habitat differences. This article is part of the theme issue 'Natural processes influencing pollinator health: from chemistry to landscapes'.

Thrice out of Asia and the adaptive radiation of the western honey bee.

The origin of the western honey bee Apis mellifera has been intensely debated. Addressing this knowledge gap is essential for understanding the evolution and genetics of one of the world's most important pollinators. By analyzing 251 genomes from 18 native subspecies, we found support for an Asian origin of honey bees with at least three expansions leading to African and European lineages. The adaptive radiation of honey bees involved selection on a few genomic "hotspots." We found 145 genes with independent signatures of selection across all bee lineages, and these genes were highly associated with worker traits. Our results indicate that a core set of genes associated with worker and colony traits facilitated the adaptive radiation of honey bees across their vast distribution.

Germline ATM variants predispose to melanoma: a joint analysis across the GenoMEL and MelaNostrum consortia.

PURPOSE: Ataxia-Telangiectasia Mutated (ATM) has been implicated in the risk of several cancers, but establishing a causal relationship is often challenging. Although ATM single-nucleotide polymorphisms have been linked to melanoma, few functional alleles have been identified. Therefore, ATM impact on melanoma predisposition is unclear. METHODS: From 22 American, Australian, and European sites, we collected 2,104 familial, multiple primary (MPM), and sporadic melanoma cases who underwent ATM genotyping via panel, exome, or genome sequencing, and compared the allele frequency (AF) of selected ATM variants classified as loss-of-function (LOF) and variants of uncertain significance (VUS) between this cohort and the gnomAD non-Finnish European (NFE) data set. RESULTS: LOF variants were more represented in our study cohort than in gnomAD NFE, both in all (AF = 0.005 and 0.002, OR = 2.6, 95% CI = 1.56-4.11, p < 0.01), and familial + MPM cases (AF = 0.0054 and 0.002, OR = 2.97, p < 0.01). Similarly, VUS were enriched in all (AF = 0.046 and 0.033, OR = 1.41, 95% CI = 1.6-5.09, p < 0.01) and familial + MPM cases (AF = 0.053 and 0.033, OR = 1.63, p < 0.01). In a case-control comparison of two centers that provided 1,446 controls, LOF and VUS were enriched in familial + MPM cases (p = 0.027, p = 0.018). CONCLUSION: This study, describing the largest multicenter melanoma cohort investigated for ATM germline variants, supports the role of ATM as a melanoma predisposition gene, with LOF variants suggesting a moderate-risk.

Economic Dependence and Vulnerability of United States Agricultural Sector on Insect-Mediated Pollination Service.

Deficits in insect-mediated pollination service undermine ecosystem biodiversity and function, human nutrition, and economic welfare. Global pollinator supply continues to decline, while production of pollination-dependent crops increases. Using publicly available price and production data and existing pollination field studies, we quantify economic dependence of United States crops on insect-mediated pollination service at the county level and update existing coefficients of insect dependence of sample crops when possible. Economic value dependent on pollination service totals 34.0 billion USD in 2012. Twenty percent of US counties produce 80% of total economic value attributable to insect pollinators. We compile county-level data and consider the spatial relationship between economic value dependent on insect-mediated pollination, region-specific forage suitability, and crop-specific agricultural areas within US landscapes. We identify vulnerable, highly dependent areas where habitat for wild pollinators has been reduced. These results can help inform future efforts to conserve and bolster managed and wild pollinator populations to ensure sustainable production of key agricultural crops.

Pollen Protein: Lipid Macronutrient Ratios May Guide Broad Patterns of Bee Species Floral Preferences.

Pollinator nutritional ecology provides insights into plant-pollinator interactions, coevolution, and the restoration of declining pollinator populations. Bees obtain their protein and lipid nutrient intake from pollen, which is essential for larval growth and development as well as adult health and reproduction. Our previous research revealed that pollen protein to lipid ratios (P:L) shape bumble bee foraging preferences among pollen host-plant species, and these preferred ratios link to bumble bee colony health and fitness. Yet, we are still in the early stages of integrating data on P:L ratios across plant and bee species. Here, using a standard laboratory protocol, we present over 80 plant species' protein and lipid concentrations and P:L values, and we evaluate the P:L ratios of pollen collected by three bee species. We discuss the general phylogenetic, phenotypic, behavioral, and ecological trends observed in these P:L ratios that may drive plant-pollinator interactions; we also present future research questions to further strengthen the field of pollination nutritional ecology. This dataset provides a foundation for researchers studying the nutritional drivers of plant-pollinator interactions as well as for stakeholders developing planting schemes to best support pollinators.

A screening-level assessment of the pollinator-attractiveness of ornamental nursery stock using a honey bee foraging assay.

In urban and suburban landscapes characterized by extensive designed greenspaces, the support of pollinator communities hinges significantly on floral resources provided by ornamental plants. The attractiveness of ornamental plants to pollinators, however, cannot be presumed, and some studies suggest that a majority of ornamental plant varieties receive little or no pollinator visitation. Here, we harness the sampling power of the western honey bee, a generalist pollinator whose diet breadth overlaps substantially with that of other pollinators, to survey the utilization of ornamental plants grown at three commercial nurseries in Connecticut, USA. Using a combination of DNA metabarcoding and microscopy, we identify, to genus-level, pollen samples from honey bee colonies placed within each nursery, and we compare our results with nursery plant inventories to identify the subset of cultivated genera that were visited during pollen foraging. Samples were collected weekly from May to September, encompassing the majority of the growing season. Our findings show that some plant genera known to be cultivated as ornamentals in our system, particularly ornamental trees and shrubs (e.g. Hydrangea, Rosa, Spiraea, Syringa, Viburnum), functioned as major pollen sources, but the majority of plants inventoried at our nurseries provided little or no pollen to honey bees. These results are in agreement with a growing body of literature highlighting the special importance of woody plants as resources for flower-visiting insects. We encourage further exploration of the genera highlighted in our data as potential components of pollinator-friendly ornamental greenspace.

Effective Heisenberg Model and Exchange Interaction for Strongly Correlated Systems.

We consider the extended Hubbard model and introduce a corresponding Heisenberg-like problem written in terms of spin operators. The derived formalism is reminiscent of Anderson's idea of the effective exchange interaction and takes into account nonlocal correlation effects. The results for the exchange interaction and spin susceptibility in the magnetic phase are expressed in terms of single-particle quantities. This fact not only can be used for realistic calculations of multiband systems but also allows us to reconsider a general description of many-body effects in the most interesting physical regimes, where the physical properties of the system are dominated by collective (bosonic) fluctuations. In the strongly spin-polarized limit, when the local magnetic moment is well defined, the exchange interaction reduces to a standard expression of the density functional theory that has been successfully used in practical calculations of magnetic properties of real materials.

Consistent pollen nutritional intake drives bumble bee (Bombus impatiens) colony growth and reproduction across different habitats.

Foraging behavior is a critical adaptation by insects to obtain appropriate nutrients from the environment for development and fitness. Bumble bees (Bombus spp.) form annual colonies which must rapidly increase their worker populations to support rearing reproductive individuals before the end of the season. Therefore, colony growth and reproduction should be dependent on the quality and quantity of pollen resources in the surrounding landscape. Our previous research found that B. impatiens foraging preferences to different plant species were shaped by pollen protein:lipid nutritional ratios (P:L), with foragers preferring pollen species with a ~5:1 P:L ratio. In this study, we placed B. impatiens colonies in three different habitats (forest, forest edge, and valley) to determine whether pollen nutritional quality collected by the colonies differed between areas that may differ in resource abundance and diversity. We found that habitat did not influence the collected pollen nutritional quality, with colonies in all three habitats collecting pollen averaging a 4:1 P:L ratio. Furthermore, there was no difference in the nutritional quality of the pollen collected by colonies that successfully reared reproductives and those that did not. We found however, that "nutritional intake," calculated as the colony-level intake rate of nutrient quantities (protein, lipid, and sugar), was strongly related to colony growth and reproductive output. Therefore, we conclude that B. impatiens colony performance is a function of the abundance of nutritionally appropriate floral resources in the surrounding landscape. Because we did not comprehensively evaluate the nutrition provided by the plant communities in each habitat, it remains to be determined how B. impatiens polylectic foraging strategies helps them select among the available pollen nutritional landscape in a variety of plant communities to obtain a balance of key macronutrients.

Investigating the viral ecology of global bee communities with high-throughput metagenomics.

Bee viral ecology is a fascinating emerging area of research: viruses exert a range of effects on their hosts, exacerbate impacts of other environmental stressors, and, importantly, are readily shared across multiple bee species in a community. However, our understanding of bee viral communities is limited, as it is primarily derived from studies of North American and European Apis mellifera populations. Here, we examined viruses in populations of A. mellifera and 11 other bee species from 9 countries, across 4 continents and Oceania. We developed a novel pipeline to rapidly and inexpensively screen for bee viruses. This pipeline includes purification of encapsulated RNA/DNA viruses, sequence-independent amplification, high throughput sequencing, integrated assembly of contigs, and filtering to identify contigs specifically corresponding to viral sequences. We identified sequences for (+)ssRNA, (-)ssRNA, dsRNA, and ssDNA viruses. Overall, we found 127 contigs corresponding to novel viruses (i.e. previously not observed in bees), with 27 represented by >0.1% of the reads in a given sample, and 7 contained an RdRp or replicase sequence which could be used for robust phylogenetic analysis. This study provides a sequence-independent pipeline for viral metagenomics analysis, and greatly expands our understanding of the diversity of viruses found in bee communities.

How do oral and maxillofacial surgeons manage concussion?

Craniofacial trauma results in distracting injuries that are easy to see, and as oral and maxillofacial surgeons (OMFS) we gravitate towards injuries that can be seen and are treatable surgically. However, we do tend not to involve ourselves (and may potentially overlook) injuries that are not obvious either visually or radiographically, and concussion is one such. We reviewed the records of 500 consecutive patients who presented with facial fractures at the Queen Elizabeth Hospital, Birmingham, to identify whether patients had been screened for concussion, and how they had been managed. Of the 500 cases 186 (37%) had concussion, and 174 (35%) had a more severe traumatic brain injury. The maxillofacial team documented loss of consciousness in 314 (63%) and pupillary reactions in 215 (43%). Ninety-three (19%) were referred for a neurosurgical opinion, although most of these were patients who presented with a Glasgow coma scale (GCS) of ≤13. Only 37 patients (7%) were referred to the traumatic brain injury clinic. Recent reports have indicated that 15% of all patients diagnosed with concussion have symptoms that persist for longer than two weeks. These can have far-reaching effects on recovery, and have an appreciable effect on the psychosocial aspects of the patients' lives. As we have found, over one third of patients with craniofacial trauma are concussed. We think, therefore, that all patients who have been referred to OMFS with craniofacial trauma should be screened for concussion on admission, and at the OMFS follow up clinic. In addition, there should be an agreement between consultants that such patients should be referred to the traumatic brain injury clinic for follow up.

Maternal methyl donor and cofactor supplementation in late pregnancy increases ß-cell numbers at 16 days of life in growth-restricted twin lambs.

Restricted growth before birth (IUGR) increases adult risk of Type 2 diabetes by impairing insulin sensitivity and secretion. Altered fetal one-carbon metabolism is implicated in developmental programming of adult health and disease by IUGR. Therefore, we evaluated effects of maternal dietary supplementation with methyl donors and cofactors (MMDS), designed to increase fetal supply, on insulin action in the spontaneously IUGR twin lamb. In vivo glucose-stimulated insulin secretion and insulin sensitivity were measured at days 12-14 in singleton controls (CON, n = 7 lambs from 7 ewes), twins (IUGR, n = 8 lambs from 8 ewes), and twins from ewes that received MMDS (2 g rumen-protected methionine, 300 mg folic acid, 1.2 g sulfur, 0.7 mg cobalt) daily from 120 days after mating (~0.8 of term) until delivery (IUGR+MMDS, n = 8 lambs from 4 ewes). Body composition and pancreas morphometry were assessed in lambs at day 16 IUGR reduced size at birth and increased neonatal fractional growth rate. MMDS normalized long bone lengths but not other body dimensions of IUGR lambs at birth. IUGR did not impair glucose control or insulin action at days 12-14, compared with controls. MMDS increased metabolic clearance rate of insulin and increased ß-cell numerical density and tended to improve insulin sensitivity, compared with untreated IUGR lambs. This demonstrates that effects of late-pregnancy methyl donor supplementation persist until at least the third week of life. Whether these effects of MMDS persist beyond early postnatal life and improve metabolic outcomes after IUGR in adults and the underlying mechanisms remain to be determined.

Macronutrient ratios in pollen shape bumble bee (Bombus impatiens) foraging strategies and floral preferences.

To fuel their activities and rear their offspring, foraging bees must obtain a sufficient quality and quantity of nutritional resources from a diverse plant community. Pollen is the primary source of proteins and lipids for bees, and the concentrations of these nutrients in pollen can vary widely among host-plant species. Therefore we hypothesized that foraging decisions of bumble bees are driven by both the protein and lipid content of pollen. By successively reducing environmental and floral cues, we analyzed pollen-foraging preferences of Bombus impatiens in (i) host-plant species, (ii) pollen isolated from these host-plant species, and (iii) nutritionally modified single-source pollen diets encompassing a range of protein and lipid concentrations. In our semifield experiments, B impatiens foragers exponentially increased their foraging rates of pollen from plant species with high protein:lipid (P:L) ratios; the most preferred plant species had the highest ratio (∼4.6:1). These preferences were confirmed in cage studies where, in pairwise comparisons in the absence of other floral cues, B impatiens workers still preferred pollen with higher P:L ratios. Finally, when presented with nutritionally modified pollen, workers were most attracted to pollen with P:L ratios of 5:1 and 10:1, but increasing the protein or lipid concentration (while leaving ratios intact) reduced attraction. Thus, macronutritional ratios appear to be a primary factor driving bee pollen-foraging behavior and may explain observed patterns of host-plant visitation across the landscape. The nutritional quality of pollen resources should be taken into consideration when designing conservation habitats supporting bee populations.

Genome-wide analysis of signatures of selection in populations of African honey bees (Apis mellifera) using new web-based tools.

BACKGROUND: With the development of inexpensive, high-throughput sequencing technologies, it has become feasible to examine questions related to population genetics and molecular evolution of non-model species in their ecological contexts on a genome-wide scale. Here, we employed a newly developed suite of integrated, web-based programs to examine population dynamics and signatures of selection across the genome using several well-established tests, including F ST, pN/pS, and McDonald-Kreitman. We applied these techniques to study populations of honey bees (Apis mellifera) in East Africa. In Kenya, there are several described A. mellifera subspecies, which are thought to be localized to distinct ecological regions. RESULTS: We performed whole genome sequencing of 11 worker honey bees from apiaries distributed throughout Kenya and identified 3.6 million putative single-nucleotide polymorphisms. The dense coverage allowed us to apply several computational procedures to study population structure and the evolutionary relationships among the populations, and to detect signs of adaptive evolution across the genome. While there is considerable gene flow among the sampled populations, there are clear distinctions between populations from the northern desert region and those from the temperate, savannah region. We identified several genes showing population genetic patterns consistent with positive selection within African bee populations, and between these populations and European A. mellifera or Asian Apis florea. CONCLUSIONS: These results lay the groundwork for future studies of adaptive ecological evolution in honey bees, and demonstrate the use of new, freely available web-based tools and workflows ( http://usegalaxy.org/r/kenyanbee ) that can be applied to any model system with genomic information.

Neurophysiological mechanisms underlying sex- and maturation-related variation in pheromone responses in honey bees (Apis mellifera).

In the honey bee (Apis mellifera), social organization is primarily mediated by pheromones. Queen-produced 9-oxo-2-decenoic acid (9-ODA) functions as both a social and sex pheromone, eliciting attraction in both female workers and male drones, but also affecting other critical aspects of worker physiology and behavior. These effects are also maturation related, as younger workers and sexually mature drones are most receptive to 9-ODA. While changes in the peripheral nervous system drive sex-related differences in sensitivity to 9-ODA, the mechanisms driving maturation-related shifts in receptivity to 9-ODA remain unknown. Here, we investigate the hypothesis that changes at the peripheral nervous system may be mediating plastic responses to 9-ODA by characterizing expression levels of AmOR11 (the olfactory receptor tuned to 9-ODA) and electrophysiological responses to 9-ODA. We find that receptor expression correlates significantly with behavioral receptivity to 9-ODA, with nurses and sexually mature drones exhibiting higher levels of expression than foragers and immature drones, respectively. Electrophysiological responses to 9-ODA were not found to correlate with behavioral receptivity or receptor expression, however. Thus, while receptor expression at the periphery exhibits a level of plasticity that correlates with behavior, the mechanisms driving maturation-dependent responsiveness to 9-ODA appear to function primarily in the central nervous system.

Bee nutrition and floral resource restoration.

Bee-population declines are linked to nutritional shortages caused by land-use intensification, which reduces diversity and abundance of host-plant species. Bees require nectar and pollen floral resources that provide necessary carbohydrates, proteins, lipids, and micronutrients for survival, reproduction, and resilience to stress. However, nectar and pollen nutritional quality varies widely among host-plant species, which in turn influences how bees forage to obtain their nutritionally appropriate diets. Unfortunately, we know little about the nutritional requirements of different bee species. Research must be conducted on bee species nutritional needs and host-plant species resource quality to develop diverse and nutritionally balanced plant communities. Restoring appropriate suites of plant species to landscapes can support diverse bee species populations and their associated pollination ecosystem services.

Plasma osteopontin concentrations in patients with cutaneous melanoma.

An effective circulating tumour marker is needed for melanoma especially with the advent of targeted therapies. Gene expression studies examining primary melanomas have shown that increased expression of osteopontin (SPP1) is associated with poor prognosis. Studies subsequently reported higher blood levels in melanoma patients with metastatic disease than those without. This study was designed to determine whether osteopontin plasma concentrations in disease-free patients after initial treatment predict survival. An enzyme-linked immunosorbent assay (ELISA) was used to measure osteopontin levels in stored plasma samples (N=215) from participants in the Leeds Melanoma Cohort. AJCC stage at sampling was statistically significant associated with osteopontin levels (p=0.03). Participants with untreated stage IV disease at sampling (n=10) had higher median osteopontin levels compared to those with treated stage I-III disease (n=158) (p<0.001) confirming previous findings. There was a trend for increased risk of death with increasing osteopontin levels but this was not statistically significant. If a level of 103.14 ng/ml (95th centile of healthy controls) was taken as the upper end of the normal range then 2.5% of patients with treated stage I-III (4/110), 17.6% of patients with untreated stage III (3/17) and 30% of patients with untreated stage IV disease (3/10) had higher levels. These findings suggest that plasma osteopontin levels warrant investigation as a tumour marker in a larger study in which the significance of change in levels over time should be studied in relation to detectable disease recurrence.

Neonatal exendin-4 reduces growth, fat deposition and glucose tolerance during treatment in the intrauterine growth-restricted lamb.

BACKGROUND: IUGR increases the risk of type 2 diabetes mellitus (T2DM) in later life, due to reduced insulin sensitivity and impaired adaptation of insulin secretion. In IUGR rats, development of T2DM can be prevented by neonatal administration of the GLP-1 analogue exendin-4. We therefore investigated effects of neonatal exendin-4 administration on insulin action and ß-cell mass and function in the IUGR neonate in the sheep, a species with a more developed pancreas at birth. METHODS: Twin IUGR lambs were injected s.c. daily with vehicle (IUGR+Veh, n = 8) or exendin-4 (1 nmol.kg⁻¹, IUGR+Ex-4, n = 8), and singleton control lambs were injected with vehicle (CON, n = 7), from d 1 to 16 of age. Glucose-stimulated insulin secretion and insulin sensitivity were measured in vivo during treatment (d 12-14). Body composition, ß-cell mass and in vitro insulin secretion of isolated pancreatic islets were measured at d 16. PRINCIPAL FINDINGS: IUGR+Veh did not alter in vivo insulin secretion or insulin sensitivity or ß-cell mass, but increased glucose-stimulated insulin secretion in vitro. Exendin-4 treatment of the IUGR lamb impaired glucose tolerance in vivo, reflecting reduced insulin sensitivity, and normalised glucose-stimulated insulin secretion in vitro. Exendin-4 also reduced neonatal growth and visceral fat accumulation in IUGR lambs, known risk factors for later T2DM. CONCLUSIONS: Neonatal exendin-4 induces changes in IUGR lambs that might improve later insulin action. Whether these effects of exendin-4 lead to improved insulin action in adult life after IUGR in the sheep, as in the PR rat, requires further investigation.

Placental restriction reduces insulin sensitivity and expression of insulin signaling and glucose transporter genes in skeletal muscle, but not liver, in young sheep.

Poor growth before birth is associated with impaired insulin sensitivity later in life, increasing the risk of type 2 diabetes. The tissue sites at which insulin resistance first develops after intrauterine growth restriction (IUGR), and its molecular basis, are unclear. We have therefore characterized the effects of placental restriction (PR), a major cause of IUGR, on whole-body insulin sensitivity and expression of molecular determinants of insulin signaling and glucose uptake in skeletal muscle and liver of young lambs. Whole-body insulin sensitivity was measured at 30 d by hyperinsulinaemic euglycaemic clamp and expression of insulin signaling genes (receptors, pathways, and targets) at 43 d in muscle and liver of control (n = 15) and PR (n = 13) lambs. PR reduced size at birth and increased postnatal growth, fasting plasma glucose (+15%, P = 0.004), and insulin (+115%, P = 0.009). PR reduced whole-body insulin sensitivity (-43%, P < 0.001) and skeletal muscle expression of INSR (-36%), IRS1 (-28%), AKT2 (-44%), GLUT4 (-88%), GSK3α (-35%), and GYS1 (-31%) overall (each P < 0.05) and decreased AMPKγ3 expression in females (P = 0.030). PR did not alter hepatic expression of insulin signaling and related genes but increased GLUT2 expression (P = 0.047) in males. Whole-body insulin sensitivity correlated positively with skeletal muscle expression of IRS1, AKT2, HK, AMPKγ2, and AMPKγ3 in PR lambs only (each P < 0.05) but not with hepatic gene expression in control or PR lambs. Onset of insulin resistance after PR and IUGR is accompanied by, and can be accounted for by, reduced expression of insulin signaling and metabolic genes in skeletal muscle but not liver.