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Bees are important pollinators and are essential for the reproduction of many plants in natural and agricultural ecosystems. However, bees can have adverse ecological effects when introduced to areas outside of their native geographic ranges. Dozens of non-native bee species are currently found in North America and have raised concerns about their potential role in the decline of native bee populations. Osmia taurus Smith (Hymenoptera: Megachilidae) is a mason bee native to eastern Asia that was first reported in the United States in 2002. Since then, this species has rapidly expanded throughout the eastern part of North America. Here, we present a comprehensive review of the natural history of O. taurus, document its recent history of spread through the United States and Canada, and discuss the evidence suggesting its potential for invasiveness. In addition, we compare the biology and history of colonization of O. taurus to O. cornifrons (Radoszkowski), another non-native mason bee species now widespread in North America. We highlight gaps of knowledge and future research directions to better characterize the role of O. taurus in the decline of native Osmia spp. Panzer and the facilitation of invasive plant-pollinator mutualisms.

High anxiety may be related insufficient sensitivity to changing reinforcement during operant learning. Whether such findings are specific to anxiety is unclear given a wider literature relating negative affect to abnormal learning and the possibility that relationships are not consistent across incentive types (i.e. punishment and reward) and outcomes (i.e., positive or negative). In two separate samples ( = 76; = 49), participants completed an operant learning task with positive, negative, and neutral socio-affective feedback, designed to assess adaptive responses to changing environmental volatility. Contrary to expectations, general affective distress, rather than anxiety or depression specifically, was related to an increase, rather than a decrease, in the rate of learning for negative outcomes in volatile, relative to stable, environments. Our results suggest an important but general role in anxiety and depression of overweighting negative feedback when the value of an action becomes uncertain, as when environmental volatility increases.

In the coastal mid-Atlantic region of the USA, landscapes are a mosaic of upland habitats (woodland, grassland, old fields and farmland) and low-lying coastal salt marsh. Flooding and salinization of coastal areas due to sea-level rise result in the conversion of upland habitats to salt marsh, and change the relative proportion of habitat types surrounding coastal farmland. This has the potential to influence population sizes of organisms living in this area and could alter the ecosystem services, such as pollination, that these habitats provide. To examine the potential outcome of these habitat conversions, we used blue vane traps at 14 sites along the Eastern Shore of Virginia (USA) to compare the bee communities of salt marsh, old fields and agricultural fields. Although there was no difference among habitat types for total bee abundance per site, we found that the coastal marsh is depauperate in bee species relative to old fields and agricultural fields, and that the bee species using the marsh habitat tend to be specialists of plant families that are common in the marsh (Asteraceae and Malvaceae) but are relatively uncommon in local agriculture. Thus, the transition of upland areas to marsh not only has the potential to impact agricultural productivity directly through salt water intrusion, ultimately it may also reduce the species richness of native bees available to provide pollination services to coastal agriculture.

The mothSymmetrischema lavernella(Chambers) (Lepidoptera: Gelechiidae) has two feeding strategies on its host plantPhysalisLinnaeus (Solanaceae): a fruitworm that feeds on developing ovules in a fruit and a budworm that consumes a floral bud. The fruitworm strategy occurs when a neonate caterpillar enters the ovary of a flower bud above a size threshold (~4 mm inPhysalis heterophyllaNees), consumes the developing ovules, and pupates in the fruit. InP.heterophylla, occupancy of the ovary byS. lavernellacauses fruit development to occur in the absence of pollination, indicating that the caterpillar initiates developmental pathways associated with pollination. The budworm strategy occurs in buds below ~4 mm, involves consumption of the ovary and immature anthers, and results in pupation inside the uninflated calyx. The two strategies co-occur on plants, determined by the sizes of the available buds at the time of oviposition. The most prominent natural enemy ofS. lavernellausing the fruitworm strategy was the frugivorous caterpillarHeliothis subflexa(Guenée) (Lepidoptera: Noctuidae), also a specialist ofPhysalis. The largerHeliothis subflexafeeds on the fruit externally, consumesS. lavernella, and caused 31.3% of fruitworm mortality in field surveys. Parasitoids included wasps (Hymenoptera) of the families Braconidae, Ichneumonidae, and Chalcididae.

Pollination strongly contributes to food production, and often relies on pollinating insects. However, atmospheric pollution may interfere with pollination by disrupting floral plumes that pollinators use to navigate to flowers.In this study, we examine the impacts of pollution-induced elevated ozone levels on the composition of a floral blend ofNicotiana alataand examine the response of innate and trainedManduca sextato the ozone-altered blend.Ozone exposure altered the floral blend ofN. alata, and disrupted the innate attraction of naïveM. sextato the altered blend. However, associative learning can offset this disruption in attraction. Moths that were enticed with visual cues to an artificial flower emitting an ozonated blend learned to associate this blend with a nectar reward after just one rewarded experience. More importantly, moths that were rewarded while experiencing the unozonated floral blend of their host subsequently found the ozonated floral blend of the same host attractive, most likely due to experience-based reinforcement of ozone-insensitive cues in the blend.The attraction of moths to both unaltered and ozonated plumes is critical for tolerating polluted landscapes. At the host plant, where moths feed, floral emissions are relatively pure. As floral odors travel away from the host, however, they become degraded by pollution. Therefore, targeting the flower requires recognizing both conditions of the odor. The ability to generalize between the pure and ozone-altered scents may enable pollinators likeM. sextato maintain communication with their flowers and reduce the impact anthropogenic oxidants may have on plant-pollinator systems.

Flowers emit mixtures of scents that mediate plant-insect interactions such as attracting insect pollinators. Because of their volatile nature, however, floral scents readily react with ozone, nitrate radical, and hydroxyl radical. The result of such reactions is the degradation and the chemical modification of scent plumes downwind of floral sources. Large Eddy Simulations (LES) are developed to investigate dispersion and chemical degradation and modification of floral scents due to reactions with ozone, hydroxyl radical, and nitrate radical within the atmospheric surface layer. Impacts on foraging insects are investigated by utilizing a random walk model to simulate insect search behavior. Results indicate that even moderate air pollutant levels (e.g., ozone mixing ratios greater than 60 parts per billion on a per volume basis, ppbv) substantially degrade floral volatiles and alter the chemical composition of released floral scents. As a result, insect success rates of locating plumes of floral scents were reduced and foraging times increased in polluted air masses due to considerable degradation and changes in the composition of floral scents. Results also indicate that plant-pollinator interactions could be sensitive to changes in floral scent composition, especially if insects are unable to adapt to the modified scentscape. The increase in foraging time could have severe cascading and pernicious impacts on the fitness of foraging insects by reducing the time devoted to other necessary tasks.

Endoparasitoids develop inside the body of a host organism and, if successful, eventually kill their host in order to reach maturity. Host species can vary in their suitability for a developing endoparasitoid; in particular, the host immune response, which can suppress egg hatching and larval development, has been hypothesized to be one of the most important determinants of parasitoid host range. In this study, we investigated whether three bumblebee host species (Bombus bimaculatus, Bombus griseocollis, and Bombus impatiens) varied in their suitability for the development of a shared parasitoid, the conopid fly (Conopidae, Diptera) and whether the intensity of host encapsulation response, an insect immune defense against invaders, could predict parasitoid success. When surgically implanted with a nylon filament, B. griseocollis exhibited a stronger immune response than both B. impatiens and B. bimaculatus. Similarly, B. griseocollis was more likely to melanize conopid larvae from natural infections and more likely to kill conopids prior to its own death. Our results indicate that variation in the strength of the general immune response of insects may have ecological implications for sympatric species that share parasites. We suggest that, in this system, selection for a stronger immune response may be heightened by the pattern of phenological overlap between local host species and the population peak of their most prominent parasitoid.

Alterations of host behaviour in response to parasitism are widely documented. Modified host behaviour is considered an adaptive manipulation when it is induced by and provides a clear benefit to the parasite. Variability in the response of host organisms to parasitic manipulations can result in some hosts being more suitable than others if failure to induce a behaviour has fitness costs for the parasite. Individuals of the European bumblebee Bombus terrestris (Hymenoptera, Apidae) that are parasitized by the endoparasitic larvae of a conopid fly (Conopidae, Diptera) bury themselves in soil just before death. This behaviour, which is of little consequence to the dying host, improves the survival and fitness of the parasitoid. In this study, we examined whether a parasitoid conopid fly, Physocephala tibialis, can successfully induce self-burial or ‘grave-digging’ behaviour in three bumblebee host species (B. bimaculatus, B. griseocollis and B. impatiens). Self-burial behaviour was expressed in all three host species, but at a far lower rate (17.4%) in B. griseocollis than in the other two species, which showed nearly equal rates of self-burial when parasitized (∼70%). Bombus impatiens and B. bimaculatus are more closely related to each other than to B. griseocollis, suggesting that genetic relatedness may influence host responsiveness to the parasitoid. We also found that larger hosts produced larger fly pupae, and that larger pupae generated bigger adult flies. In parasitoid literature, host suitability is often discussed in the context of receptiveness to oviposition and physiological resistance to infection. We posit that the ability to induce an important behavioural response influences host competency as well, and that host susceptibility to behavioural manipulation could have implications for selection.

Lake Bosten is the largest inland freshwater lake in China and plays a key role in the local arid-area ecosystem. This study focuses on the dynamics of water salinity of Lake Bosten in the past 55 years (1955-2009) and intends to quantify the associations between the water salinity and the magnitudes of water level, inflow, outflow, total wastewater drainage into the lake, including industrial and residential wastewater. Correlation analysis reveals that the water salinity has strong associations with those six factors (R = -0.810, -0.510, -0.844, 0.903, 0.855, and 0.685, respectively). We predict that water level, inflow and water salinity of Lake Bosten will decline in 2010-2019. This study recommends a reduction in salt input to the Bosten River by reducing industrial wastewater discharge along the river and the development of clean production technology.

In recent decades, several North American bumble bee (Bombus spp.) species have undergone precipitous declines. It is suspected that a parasite or pathogen may be responsible, yet few studies have examined the extent of parasitism and the ecology of host–parasite relationships in U.S. bumble bee populations. A season-long survey of bumble bees in seven grassland meadows of the northern Shenandoah Valley and Piedmont regions in Virginia was conducted in 2011 to ascertain the local prevalence and predictors of parasitism by the internal parasites Nosema and Crithidia, and by parasitoid conopid flies. In total, 835 bumble bees representing six species were examined. Using visual detection methods, we determined that 25% of bees were infected with parasitoid larvae, 17.4% with Crithidia, and 7.3% with Nosema. Nosema infections were more prevalent and intense in locally rare than locally common species, with the two rarest bumble bees [B. fervidus (Fabricius) and B. auricomus (Robertson)], newly suspected to be in decline, having the highest frequencies of infection (11–17.8%). Crithidia was generally more prevalent in common bumble bee species (11–35%). With fewer than 5% of individuals infected, the two rarest species had the lowest frequencies of Crithidia. Conopid fly larvae were more prevalent in common species. Body size significantly influenced the probability of parasitism by conopids and Crithidia. Smaller bees were more likely to be parasitised by Crithidia. Larger bees were more likely to be parasitised by conopid flies, although the largest bee species (B. auricomus) was not infected by conopids in this study.

Complexes formed between phi29 DNA polymerase (DNAP) and DNA fluctuate discretely between the pre-translocation and post-translocation states on the millisecond time scale. The translocation fluctuations can be observed in ionic current traces when individual complexes are captured atop the α-hemolysin nanopore in an electric field. The presence of complementary 2′-deoxynucleoside triphosphate (dNTP) shifts the equilibrium across the translocation step toward the post-translocation state. Here we have determined quantitatively the kinetic relationship between the phi29 DNAP translocation step and dNTP binding. We demonstrate that dNTP binds to phi29 DNAP-DNA complexes only after the transition from the pre-translocation state to the post-translocation state; dNTP binding rectifies the translocation but it does not directly drive the translocation. Based on the measured time traces of current amplitude, we developed a method for determining the forward and reverse translocation rates, and the dNTP association and dissociation rates, individually at each dNTP concentration and each voltage. The translocation rates, and their response to force, match those determined for phi29 DNAP-DNA binary complexes and are unaffected by dNTP. The dNTP association and dissociation rates do not vary as a function of voltage, indicating that force does not distort the polymerase active site, and that dNTP binding does not directly involve a displacement in the translocation direction. This combined experimental and theoretical approach, and the results obtained, provide a framework for separately evaluating the effects of biological variables on the translocation transitions and their effects on dNTP binding.

Parasites and mutualists can wield great influence on the fitness of social organisms, yet the effect that the host’s social structure has on the evolution of parasites, commensals, and mutualists (collectively referred to here as symbionts) is poorly known. Evolutionary theory suggests that host social structure may select for more cooperative symbiont strains in comparison to symbionts of solitary hosts. We compared the productivity of one social and one solitary bee species (Halictus ligatus and Augochlora pura) in the family Halictidae with and without the presence of their nematode symbionts (Acrostichus halicti and Acrostichus puri, respectively). We measured the number of offspring produced, the number of cells provisioned, and nesting activity (for Au. pura) to test the hypothesis that symbionts specific to a social host exhibit greater cooperation than symbionts specific to a solitary host. Infected and uninfected nests of both species did not differ in any fitness estimates indicating that: (1) Acrostichus species are commensals, or at least lack large fitness effects on their hosts, and (2) the transition from association with a solitary host to association with a social host that lives in small colonies does not have detectable effects on the evolution of conflict and cooperation in this system. This is the first comparative study to test the idea that host social structure may influence the evolution of symbionts; future work should compare closely related mutualists and parasites of more advanced eusocial insects to mutualists and parasites of solitary insects.

A direct competitive enzyme-linked immunosorbent assay (dc-ELISA) was developed to measure anilofos levels in agricultural and environmental samples. The ELISA was developed using rabbit polyclonal antibodies against a hapten-protein conjugate of anilofos-bovine serum albumin. The limit of detection was 0.1 μg L(-1), and there was no cross-reactivity with other related pesticides or structurally similar compounds. The matrix effects of rice (aromatic rice, white rice, brown rice), corn, barley, wheat and soil were measured and removed by extraction and dilution with phosphate buffered saline with 0.05% Tween-20. For water samples (tap water and river water), the matrix effects were also removed by dilution with phosphate buffered saline with Tween-20. The detection limits for anilofos in authentic samples (aromatic rice, white rice, brown rice, corn, barley, wheat, soil, tap water and river water) were 2, 2, 2, 3, 2, 2, and 2 μg kg(-1), and 0.5 and 1 μg L(-1), respectively . The anilofos recovery ranged from 81.0-116.0% with a coefficient of variation of 1.7-9.0%. The method was validated using GC, and the results showed good correlation with the dc-ELISA data (r(2) = 0.9795). Forty-two cereal samples were randomly collected from different supermarkets and analyzed using the developed dc-ELISA. No anilofos was found in these products. The developed immunoassay is suitable for rapid quantitation of anilofos residues.

Complexes formed between the bacteriophage phi29 DNA polymerase (DNAP) and DNA fluctuate between the pre-translocation and post-translocation states on the millisecond time scale. These fluctuations can be directly observed with single-nucleotide precision in real-time ionic current traces when individual complexes are captured atop the alpha-hemolysin nanopore in an applied electric field. We recently quantified the equilibrium across the translocation step as a function of applied force (voltage), active-site proximal DNA sequences, and the binding of complementary dNTP. To gain insight into the mechanism of this step in the DNAP catalytic cycle, in this study, we have examined the stochastic dynamics of the translocation step. The survival probability of complexes in each of the two states decayed at a single exponential rate, indicating that the observed fluctuations are between two discrete states. We used a robust mathematical formulation based on the auto-correlation function to extract the forward and reverse rates of the transitions between the pre-translocation state and the post-translocation state from ionic current traces of captured phi29 DNAP-DNA binary complexes. We evaluated each transition rate as a function of applied voltage to examine the energy landscape of the phi29 DNAP translocation step. The analysis reveals that active-site proximal DNA sequences influence the depth of the pre-translocation and post-translocation state energy wells and affect the location of the transition state along the direction of the translocation.

This prospective, randomized, single blind, single operator study was conducted to compare hemodynamic responses when endotracheal intubation was performed using the Bonfils intubation fibrescope versus the C-MAC videolaryngoscope.Forty-four ASA I patients aged between 18 and 60 years, scheduled for elective surgery requiring endotracheal intubation were recruited. They were randomized into the Bonfils group or C-MAC group. Hemodynamic changes, laryngeal view, duration of intubation and post intubation complications were evaluated. Mean arterial pressure, heart rate and oxygen saturation were monitored pre and post-induction, pre and post-intubation, and at 1 minute intervals thereafter for 10 minutes.Endotracheal intubation was successful at first attempt in 90.9% in both groups. Heart rate was significantly higher in the Bonfils group (p0.05) compared to the C-MAC group and values were sustained throughout the study. There was no difference in the mean arterial pressure (MAP) between the two groups. Mean time to intubation was significantly longer in the Bonfils group (28.8 vs. 24.7 seconds, p = 0.02). There were no significant differences in laryngeal view and post intubation complications between the groups.Intubation using the Bonfils intubation fibrescope took longer, and resulted in significantly higher heart rate when compared with the C-MAC videolaryngoscope.

Few baseline data exist regarding the role of wild, primarily native, non-Apis bees in pollinating crops through the growing season in the mid-Atlantic United States. Apis mellifera L., honey bees, generally are assumed to provide the majority of crop pollination, with the value of pollination provided by non-Apis bees estimated at between one-half and one-sixth the value of honey bees, though many non-Apis bees are known to be more effective in pollinating some crops. In this study, the first documenting wild bees visiting crop flowers through the growing season, non-Apis bees accounted for the majority of crop visitation for several economically important entomophilous crops in Virginia, such as apple, blueberry, caneberry, and cucurbit) and likely provided most of the pollination. Wild bees made up between 68% (in caneberries) and 83% (in cucurbits) of bees visiting crop flowers. Between 43 and 59 non-Apis bee species visited flowers of each crop (105 species overall). Species turnover was very high between sites, ranging from only 13% shared species in pairwise comparisons for blueberries to 30% shared species for caneberries. Native bee taxa most abundant on crops were Andrena F., mining bees, Bombus Latreille, bumble bees, and Osmia Panzer, mason bees, on apples and blueberries; Losioglossum Curtis, sweat bees, on caneberries; and Peponapis pruinosa Say, squash bees, and Bombus on cucurbits. Overall, this study highlights the substantial role of native bees in agricultural pollination in this region.

Complexes of phi29 DNA polymerase and DNA fluctuate on the millisecond time scale between two ionic current amplitude states when captured atop the α-hemolysin nanopore in an applied field. The lower amplitude state is stabilized by complementary dNTP and thus corresponds to complexes in the post-translocation state. We have demonstrated that in the upper amplitude state, the DNA is displaced by a distance of one nucleotide from the post-translocation state. We propose that the upper amplitude state corresponds to complexes in the pre-translocation state. Force exerted on the template strand biases the complexes toward the pre-translocation state. Based on the results of voltage and dNTP titrations, we concluded through mathematical modeling that complementary dNTP binds only to the post-translocation state, and we estimated the binding affinity. The equilibrium between the two states is influenced by active site-proximal DNA sequences. Consistent with the assignment of the upper amplitude state as the pre-translocation state, a DNA substrate that favors the pre-translocation state in complexes on the nanopore is a superior substrate in bulk phase for pyrophosphorolysis. There is also a correlation between DNA sequences that bias complexes toward the pre-translocation state and the rate of exonucleolysis in bulk phase, suggesting that during DNA synthesis the pathway for transfer of the primer strand from the polymerase to exonuclease active site initiates in the pre-translocation state.

Despite the robust structure of polyamidoamine (PAMAM) dendrimers, they are not stable when complexed with surfactants. Modification of PAMAM dendrimers by grafting PEG chains on the surface of PAMAM substantially improves its colloidal stability in the presence of sodium dodecyl sulfate (SDS). Michael addition reaction was employed to synthesize PEGylated-PAMAM by activating MPEG with 4-nitrophenylchloroformate. 1 H NMR spectrum confirmed that 32 PEG chains were successfully grafted on the PAMAM surface, and the hydrodynamic radius of PEGylated-PAMAM was found to be ∼6.8 nm. The PEGylated-PAMAM dendrimers did not aggregate in the presence of up to 100 mM SDS as the complexes were sterically stabilized by PEG chains. ITC and zeta potential measurements revealed that the binding mechanism of SDS and PEGylated-PAMAM was induced by electrostatic interaction and polymer-induced micellization of SDS on PEG chains. The interaction of PEGylated-PAMAM and amphiphilic molecules, such as SDS was elucidated, and this provided a useful basis for the application PEGylated-PAMAM in drug delivery.

Oral cancer is the sixth most common human cancer, with a high morbidity rate and an overall 5-year survival rate of less than 50%. It is often not diagnosed until it has reached an advanced stage. Therefore, an early diagnostic and stratification strategy is of great importance for oral cancer. In the current study, urine samples of patients with oral squamous cell carcinoma (OSCC, n = 37), oral leukoplakia (OLK, n = 32) and healthy subjects (n = 34) were analyzed by gas chromatography-mass spectrometry (GC–MS). Using multivariate statistical analysis, the urinary metabolite profiles of OSCC, OLK and healthy control samples can be clearly discriminated and a panel of differentially expressed metabolites was obtained. Metabolites, valine and 6-hydroxynicotic acid, in combination yielded an accuracy of 98.9%, sensitivity of 94.4%, specificity of 91.4%, and positive predictive value of 91.9% in distinguishing OSCC from the controls. The combination of three differential metabolites, 6-hydroxynicotic acid, cysteine, and tyrosine, was able to discriminate between OSCC and OLK with an accuracy of 92.7%, sensitivity of 85.0%, specificity of 89.7%, and positive predictive value of 91.9%. This study demonstrated that the metabolite markers derived from this urinary metabolite profiling approach may hold promise as a diagnostic tool for early stage OSCC and its differentiation from other oral conditions.

The ability to predict the responses of ecological communities and individual species to human-induced environmental change remains a key issue for ecologists and conservation managers alike. Responses are often variable among species within groups making general predictions difficult. One option is to include ecological trait information that might help to disentangle patterns of response and also provide greater understanding of how particular traits link whole clades to their environment. Although this “trait-guild” approach has been used for single disturbances, the importance of particular traits on general responses to multiple disturbances has not been explored. We used a mixed model analysis of 19 data sets from throughout the world to test the effect of ecological and life-history traits on the responses of bee species to different types of anthropogenic environmental change. These changes included habitat loss, fragmentation, agricultural intensification, pesticides and fire. Individual traits significantly affected bee species responses to different disturbances and several traits were broadly predictive among multiple disturbances. The location of nests – above vs. below ground – significantly affected response to habitat loss, agricultural intensification, tillage regime (within agriculture) and fire. Species that nested above ground were on average more negatively affected by isolation from natural habitat and intensive agricultural land use than were species nesting below ground. In contrast below-ground-nesting species were more negatively affected by tilling than were above-ground nesters. The response of different nesting guilds to fire depended on the time since the burn. Social bee species were more strongly affected by isolation from natural habitat and pesticides than were solitary bee species. Surprisingly, body size did not consistently affect species responses, despite its importance in determining many aspects of individuals’ interaction with their environment. Although synergistic interactions among traits remain to be explored, individual traits can be useful in predicting and understanding responses of related species to global change.

Chemical signals play important roles in ecological interactions but are vulnerable to perturbation by air pollution. In polluted air masses, signals may travel shorter distances before being destroyed by chemical reactions with pollutants, thus losing their specificity. To determine which scent-mediated interactions are likely to be affected, we review existing literature to build a picture of what chemicals are commonly found in such interactions and the spatial scales at which interactions occur. We find that pollination, attraction of natural enemies of plant pests, aggregation pheromones, and mate attraction are likely to be affected. We review the scant literature on this topic and extend the hypothesis to include heretofore unexplored interactions. New research should investigate whether air pollution deleteriously affects populations of organisms that rely on scent plumes. Additionally, we need to investigate whether or not breakdown products created by the reaction of signaling chemicals with pollutants can provide usable signals, and whether or not there has been adaptation on the part of scent emitters or receivers to use either breakdown products or more robust chemical signals. The proposed research will necessarily draw on tools from atmospheric science, evolutionary biology, and ecology in furthering our understanding of the ecological implications of how air pollution modifies the scentscape.

An ad hoc network is composed of mobile nodes without the presence of a fixed infrastructure. Communications among nodes are accomplished by forwarding data packets for each other, on a hop-by-hop basis along the current connection to the destination node. In particular, vehicle-to-vehicle communications have been studied, in recent years, to improve driver safety. As more of such applications of high-mobility ad hoc networks emerge, it is critical that the routing protocol employed is capable of efficiently coping with the high-frequency of broken links (i.e., robust with respect to high-mobility). This paper presents a comprehensive comparative study in a city environment of eight representative routing protocols for wireless mobile ad hoc networks and inter-vehicular networks developed in recent years. In a city environment, communication protocols need adapt fast moving nodes (e.g., vehicles on streets) and large obstacles (e.g., office buildings). In this paper, we elaborate upon extensive simulation results based on various network scenarios, and discuss the strengths and weaknesses of these techniques with regard to their support for highly mobile nodes.

The morphological appearance and some ingredients of Panax ginseng, Panax notoginseng and Panax japonicus of the Panax genus are similar. However, their pharmacological activities are obviously different due to the significant differences in the types and quantity of saponins in each herb. In the present study, ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOFMS) was used to profile the abundances of metabolites in the three medicinal Panax herbs. Multivariate statistical analysis technique, that is, principle component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) were used to discriminate between the Panax samples. PCA of the analytical data showed a clear separation of compositions among the three medicinal herbs. The critical markers such as chikusetsusaponin IVa, ginsenoside R0, ginsenoside Rc, ginsenoside Rb1, ginsenoside Rb2 and ginsenoside Rg2 accountable for such variations were identified through the corresponding loading weights, and the tentative identification of biomarkers is completed by the accurate mass of TOFMS and high resolution and high retention time reproducibility performed by UPLC. The proposed analytical method coupled with multivariate statistical analysis is reliable to analyze a group of metabolites present in the herbal extracts and other natural products. This method can be further utilized to evaluate chemical components obtained from different plants and/or the plants of different geographical locations, thereby classifying the medicinal plant resources and potentially elucidating the mechanism of inherent phytochemical diversity.

Many ecosystem services are delivered by organisms that depend on habitats that are segregated spatially or temporally from the location where services are provided. Management of mobile organisms contributing to ecosystem services requires consideration not only of the local scale where services are delivered, but also the distribution of resources at the landscape scale, and the foraging ranges and dispersal movements of the mobile agents. We develop a conceptual model for exploring how one such mobile-agent-based ecosystem service (MABES), pollination, is affected by land-use change, and then generalize the model to other MABES. The model includes interactions and feedbacks among policies affecting land use, market forces and the biology of the organisms involved. Animal-mediated pollination contributes to the production of goods of value to humans such as crops; it also bolsters reproduction of wild plants on which other services or service-providing organisms depend. About one-third of crop production depends on animal pollinators, while 60-90% of plant species require an animal pollinator. The sensitivity of mobile organisms to ecological factors that operate across spatial scales makes the services provided by a given community of mobile agents highly contextual. Services vary, depending on the spatial and temporal distribution of resources surrounding the site, and on biotic interactions occurring locally, such as competition among pollinators for resources, and among plants for pollinators. The value of the resulting goods or services may feed back via market-based forces to influence land-use policies, which in turn influence land management practices that alter local habitat conditions and landscape structure. Developing conceptual models for MABES aids in identifying knowledge gaps, determining research priorities, and targeting interventions that can be applied in an adaptive management context.

Areas of water shortage comprise many smaller sub-areas into which water is transported from external sources. Fairness and efficiency of distribution are overriding principles. Each local area requires adequate water for community and ecological purposes as well as a supply sufficient to maximise economic growth. Within arid and semi-arid areas, there are conflicts between the sub-areas and between these three types of water use, which can erupt into violent confrontations between different user groups. This study has developed a dynamic model for equitable distribution of water in water-shortage areas and aims to optimally satisfy the requirements of each locality, given limited supplies, and to maximise the total economic benefit of the entire area. The Heihe River Basin in northwest China was chosen as the area for the pilot study.

This study aimed to evaluate the aquatic toxicity of three typical tetracycline antibiotics, including tetracycline, oxytetracycline, and chlortetracycline, on the cyanobacterium Microcystis aeruginosa. The cell density, chlorophyll a content, protein content, and enzymatic antioxidant activities were determined. The results showed that the cell growth was significantly inhibited by the three compounds at a low concentration. The chlorophyll a and protein content decreased significantly after exposure to 0.05 mg L(-1) of each compound for 9 d. When exposed to 0.2-1 mg L(-1) of tetracycline, the superoxide dismutase (SOD) activity increased, but peroxidase (POD) and catalase (CAT) activities decreased. In contrast, when exposed to oxytetracycline and chlortetracycline at different concentrations ranging from 0.2 to 1 mg L(-1) and from 0.01 to 0.05 mg L(-1), the SOD activity decreased, but the POD and CAT activities increased. These findings indicate that tetracycline antibiotics influence cell growth and protein synthesis, and they also induce oxidative stress in M. aeruginosa at environmentally similar concentrations. Thus, this study may provide further insights into the toxic effects of tetracycline antibiotics and the controlled use of antibiotics.

Lysimachia asperulifolia Poir., rough–leaf loosestrife, is a federally endangered species that is restricted to longleaf pine savanna – pocosin ecotones in North and South Carolina. Potential causes of the limited fruit and seed production typical of this species and possible effects of prescribed fire on these causes were examined. It was determined that insects rarely visit flowers and that the visitors, Augochlorella spp. and Lasioglossum spp., are not effective pollinators. However, results of artificial pollinations do not support the hypothesis that pollinator limitation alone restricts seed production. Levels of fertility and S allele diversity may vary across natural populations and, combined with ineffective pollination, enforce restricted fruit and seed production. Pollen fertility, amount of flowering, and number of fruits produced in natural populations did not increase following prescribed fire. Restricted seed germination further limits recruitment of genetic variation into populati...

Urbanization within the Tucson Basin of Arizona during the past 50+ years has fragmented the original desert scrub into patches of different sizes and ages. These remnant patches and the surrounding desert are dominated by Larrea tridentata (creosote bush), a long-lived shrub whose flowers are visited by > 120 native bee species across its range. Twenty-one of these bee species restrict their pollen foraging to L. tridentata. To evaluate the response of this bee fauna to fragmentation, we compared species incidence and abundance patterns for the bee guild visiting L. tridentata at 59 habitat fragments of known size (0.002-5 ha) and age (up to 70 years), and in adjacent desert. The 62 bee species caught during this study responded to fragmentation heterogeneously and not in direct relation to their abundance or incidence in undisturbed desert. Few species found outside the city were entirely absent from urban fragments. Species of ground-nesting L. tridentata specialists were underrepresented in smaller fragments and less abundant in the smaller and older fragments. In contrast, cavity-nesting bees (including one L. tridentata specialist) were overrepresented in the habitat fragments, probably due to enhanced nesting opportunities available in the urban matrix. Small-bodied bee species were no more likely than larger bodied species to be absent from the smaller fragments. The introduced European honey bee, Apis mellifera, was a minor faunal element at > 90% of the fragments and exerted little if any influence on the response of native bee species to fragmentation. Overall, bee response to urban habitat fragmentation was best predicted by ecological traits associated with nesting and dietary breadth. Had species been treated as individual units in the analyses, or pooled together into one analysis, these response patterns may not have been apparent. Pollination interactions with this floral host are probably not adversely affected in this system because of its longevity and ability to attract diverse pollinators but will demand careful further study to understand.

A recent alternative model to conventional coevolution, the geographic mosaic theory of coevolution, posits that reciprocal selection is episodic and local, rather than persistent and spatially extensive. However, little empirical evidence addresses this model's tenets, in particular the temporal stability of local plant–pollinator interactions. We evaluated this tenet using the richly diverse guild of bees at creosote bush (Larrea tridentata), a generalist plant that hosts many specialist bees. We systematically resampled over 2–5 years at 11 sites across the south-western USA. Incidence and abundance also were compared for survey sites sampled 20 ± 2 years earlier. Average Morisita-Horn faunal similarities of local bee guilds was 87% for sequential years and 36% after 20 years. Similarities in taxonomic composition of resampled local bee guilds could be statistically represented as a random assemblage drawn from the regional source pool of 54–68 bee species that could be expected at Larrea, weighted by regional abundance. At every site, only the minority of abundant bee species was typically persistent in local guilds, even after > 20 years. Most bee species in the Larrea guild were chronically uncommon, geographically sporadic and temporally unpredictable, attributes that render them numerically inconsequential as pollinators in their local guild. Persistence among abundant bee species in local pollinator assemblages satisfies one condition by which reciprocal selection could act locally. The well-being of these more abundant core species, and not bee diversity per se, may better characterize the health of such plant–pollinator associations. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society, 2005, 85, 319–329.

Recent declines in managed honey bee, Apis mellifera L., colonies have increased interest in the current and potential contribution of wild bee populations to the pollination of agricultural crops. Because wild bees often live in agricultural fields, their population density and contribution to crop pollination may be influenced by farming practices, especially those used to reduce the populations of other insects. We took a census of pollinators of squash and pumpkin at 25 farms in Virginia, West Virginia, and Maryland to see whether pollinator abundance was related to farming practices. The main pollinators were Peponapis pruinosa Say; honey bees, and bumble bees (Bombus spp.). The squash bee was the most abundant pollinator on squash and pumpkin, occurring at 23 of 25 farms in population densities that were commonly several times higher than that of other pollinators. Squash bee density was related to tillage practices: no-tillage farms hosted three times as great a density of squash bees as tilled farms. Pollinator density was not related to pesticide use. Honey bee density on squash and pumpkin was not related to the presence of managed honey bee colonies on farms. Farms with colonies did not have more honey bees per flower than farms that did not keep honey bees, probably reflecting the lack of affinity of honey bees for these crops. Future research should examine the economic impacts of managing farms in ways that promote pollinators, particularly pollinators of crops that are not well served by managed honey bee colonies.

Food acquisition in central-place foraging animals demands efficient detection and retrieval of resources. Most ant species rely on a mass recruitment foraging strategy, which requires that some potential foragers remain at the nest where they can be recruited to food once resources are found. Because this strategy reduces the number of workers initially looking for food, it may reduce the food detection rate while increasing the postdiscovery food retrieval rate. In previous studies this tradeoff has been analyzed by computer simulation and mathematical models. Both kinds of models show that food acquisition rate is greatly influenced by food distribution and resource patch size: as food is condensed into fewer patches, the maximal acquisition rate is achieved by a shift to fewer initial searchers and more potential recruits. In general, these models show that a mass recruitment strategy is most effective when resources are clumped. We tested this prediction in two experiments by letting laboratory colonies of the Argentine ant (Linepithema humile) forage for resources placed in different distributions. When all prey were small, retrieval rate increased with increasing resource patch size, in support of foraging models. When prey were large, however, the mass of prey returned to the colony over time was much lower than when prey were small and widely distributed. As more ants reached a large prey item, the distance the prey item was transported decreased due to a greater emphasis on feeding rather than transport. Because Argentine ants can transport more biomass externally than they can ingest, food retrieval that depends only on ingestion can depress the biomass retrieval rate. Thus, our results generally support theoretical foraging models, but we show how prey size, through differential prey-handling behavior, can produce an outcome greatly different from that predicted only on the distribution of resources.

Adult bees and wasps provide all the food their offspring require to grow from egg to adult. For a given diet, offspring body size generally increases with an increase in the amount of food consumed as a larva, but the extent to which body size is influenced by the type of food consumed is poorly known. Pollen ranges from 2–60% protein among plant species, and bees are extremely efficient at assimilating nitrogen; therefore, it seems likely that either parent bees adjust the size of larval provisions to compensate for differences in pollen protein concentration or bee offspring attain different body size depending on the pollen type(s) consumed as a larva. We presented the generalist sweat bee Lasioglossum zephyrum with pollen diets that differed in protein content and monitored offspring body size during two experiments. In a protein supplementation experiment, diets ranged from 20–66% protein and consisted of Typha pollen amended with soy protein. On a pollen/soy diet, offspring body size increased 25% with a shift from 20–37% protein, but did not increase further at greater protein concentrations. In a multiple pollen experiment, pollen diets ranged from 20–39% protein and consisted of eight pollens that differed naturally in protein concentration. The largest offspring arose from the most protein-rich pollens, whereas much smaller bees developed on protein-poor pollens. Provision size only predicted offspring size when pollen type, and therefore protein quantity, was considered. Adult foragers did not adjust provision size to compensate for pollen protein. Therefore, offspring body size appears to result from a combination of controlled (provision size) and uncontrolled (pollen quality) factors that arise out of bee foraging decisions.

TheLRRK2gene has been associated with both familial and sporadic forms of Parkinson’s disease (PD). The G2019S variant is commonly found in North African Arab and Caucasian PD patients, but this locus is monomorphic in Asians. The G2385R and R1628P variants are associated with a higher risk of developing PD in certain Asian populations but have not been studied in the Malaysian population. Therefore, we screened the G2385R and R1628P variants in 1,202 Malaysian subjects consisting of 695 cases and 507 controls. The G2385R and R1628P variants were associated with a 2.2-fold (P=0.019) and 1.2-fold (P=0.054) increased risk of PD, respectively. Our data concur with other reported findings in Chinese, Taiwanese, Singaporean, and Korean studies.

Liquids and gels are common delivery forms used in commercial ant baits, but the relative effectiveness of each is unknown. We compared the feeding responses of the Argentine ant, Linepithema humile (Mayr), to liquid and gel compositions of sucrose. In choice assays, more workers were counted on gel than liquid; however, substantially more liquid was consumed. Because workers could stand on the gel, more workers could feed simultaneously on the gel. The feeding bouts of individual workers, however, were much less efficient at extracting sucrose in gel form. Workers fed eightfold longer on the gel, yet removed fivefold less sucrose than workers feeding on liquid. This potential bias should be considered during attraction and palatability studies that use physically different bait compositions. When the toxicant fipronil was added to the compositions, a greater proportion of the colony died after workers had fed on liquid than gel baits. This finding suggests that liquid formulations may provide more effective control of Argentine ants due to the greater speed and abundance in which it is ingested.

Pollen ranges from 2.5% to 61% protein content. Most pollen proteins are likely to be enzymes that function during pollen tube growth and subsequent fertilization, but the vast range of protein quantity may not reflect only pollen–pistil interactions. Because numerous vertebrate and invertebrate floral visitors consume pollen for protein, protein content may influence floral host choice. Additionally, many floral visitors pollinate their host plants. If protein content influences pollinator visitation, then pollinators are hypothesized to select for increased protein content of host plants. We analyzed or gleaned from the literature crude pollen protein concentrations of 377 plant species from 93 plant families. Using this database, we compared pollen protein concentration with (1) pollination mode, (2) pollen collection by bees, and (3) distance from stigma to ovule, after accounting for phylogeny through paired phylogenetic comparisons and a nested ANOVA including taxonomic rank. We found that pollen pr...

For reciprocal specialization (coevolution) to occur among floral visitors and their host plants the interactions must be temporally and spatially persistent. However, studies repeatedly have shown that species composition and relative abundance of floral visitors vary dramatically at all spatial and temporal scales. We test the hypothesis that, on average, pollen specialist bee species occur more predictably at their floral hosts than pollen generalist bee species. Taxonomic floral specialization reaches its extreme among species of solitary, pollen-collecting bees, yet few studies have considered how pollen specialization by floral visitors influences their spatial constancy. We test this hypothesis using an unusually diverse bee guild that visits creosote bush ( Larrea tridentata ), the most widespread, dominant plant of the warm deserts of North America. Twenty-two strict pollen specialist and 80+ generalist bee species visit Larrea for its floral resources. The sites we sampled were separated by 0.5 to >1450 km, and spanned three distinct deserts and four vegetation zones. We found that species of Larrea pollen specialist bees occurred at more sites and tended to be more abundant than generalists. Surprisingly, spatial turnover was high for both pollen specialist and generalist bee species at all distances, and species composition of samples from sites 1–5 km apart varied as much as repeat samples made at single sites. Nevertheless, the pattern of bee species turnover was not haphazard. As distance among sites increased faunal similarity of sites decreased. Faunal similarities among sites within 250 km of each other were generally greater than if randomly distributed over all sites (the null model). No single ecological category of species (widespread, localized, Larrea pollen specialist, floral generalist) accounted for this spatial predictability. Evidently, concordant local distribution patterns of many ecologically diverse species contribute to the non-random spatial pattern. The ecological dominance of creosote bush does not confer obvious ecological advantages to its specialist floral visitors. Spatial turnover is comparable to that found for bee guilds from other biogeographic regions of the world and is not therefore limited to those bee species that inhabit highly seasonal climates, such as deserts. Philopatry and differences in bloom predictability among sites are probably more important causes for spatial turnover of bee species than are interspecific competition for nest sites or floral resources.

Recent interest in pollinator sampling, often motivated by concerns about pollinator decline, has led to the increased use of standardized sampling protocols based on passive insect traps. Compared with netting insects at host plants, these protocols have the potential to limit some types of sampling bias, such as those associated with a researcher's observational and netting skills. The most commonly deployed recent protocol is the use of colored pan traps (bowls) filled with soapy water (Aguiar and Sharkov, 1997; Calbuig, 2001; Cane et al, 2000; Leong and Thorp, 1999; Toler et al, 2005). Insects approach the bowls, land on the water, and drown. The method is particularly good at catching numerous species of bees, but can also be effective for capturing various flower-visiting flies, skippers and a wide range of other insect taxa. As a bee sampling device, pan traps have several known biases: they catch bumble bees, honey bees and bees in the genus Colletes much less frequently than expected by their perceived abundance (e.g., Toler et al, 2005). Pan traps are especially good at catching halictid bees (Family Halictidae). Because of these biases, researchers sometimes use a modest amount of net collecting on flowers to accompany pan traps. Other potential biases remain to be studied, such as whether the effectiveness of pan traps is inversely related to flower abundance, a bias suspected by several researchers but not yet studied. Based on their pan-trapping study, Toler et al (2005) concluded that the predominant flower color in the plant community did not influence the relative attractiveness of particular pan trap colors, but they did not study the effect of floral abundance per se. Depending on a researcher's interest in deploying pan traps, these biases may or may not generate concern. Pan traps seem very well suited to testing for the presence of particular bee species in the community (Leong and Thorp, 1999), including many parasitic bee species that are seldom caught at flowers. They also provide a very valuable tool for augmenting other collecting methods, especially when there are few host plants to sample (e.g., early spring). Work by Cane et al. (2000) included a comparison of pan traps versus intensive netting to sample the very diverse and well known flower-visiting insect fauna of creosote bush. These workers concluded that pan trapping was of limited use in detecting the creosote bush fauna because of numerous species caught by netting but not by pan traps. Pan traps did catch many bee species not netted at creosote bush, however. Because netting in that study was restricted to creosote bush, there was no basis to compare the relative effectiveness of netting versus pan trapping for sampling a local bee fauna in the wider flower-rich community. In 2002 in northern Virginia, we carried out an intensive netting/observational survey of floral visitors within one hectare plots at Blandy Experimental Farm, an ecological experiment station of the University of Virginia. The sampled habitat was an open field and the sampling protocol comprised net sampling on the six most prominent plant species in the community from 8:00-16:00 hrs Eastern Daylight Time. Each plant species was surveyed for a total of 2.25 hrs, spread equally across the sampling period. Each of three researchers sampled all plant species in succession, one species at a time, three times across the sampling period (8:00-10:00, 11:00-13:00, 14:00-16:00). Survey periods lasted 15 mins per plant species per researcher, with researchers moving through the entire plot during that period. Bee species that could be recognized on the wing (e.g., Apis mellifera) were noted but not captured. To compare the effectiveness of pan trapping to such an intensive netting protocol at one of our sites, we placed a line of 30 pan traps (6 oz Solo bowls painted fluorescent blue, fluorescent yellow, or left white) in a diagonal line across the plot

The effects of ruminant whey and its purified fractions on neutrophil chemotaxis and superoxide production in sheep were studied. Both colostral whey and milk whey were found to inhibit chemotaxis regardless of whether they were autologous or homologous, but the inhibitory effects were abolished by washing neutrophils with culture medium before their use in the chemotaxis assay. Colostral whey and milk whey also inhibited the chemotactic activity of zymosan-activated serum. Whey fractions of various degrees of purity such as lactoferrin, lacto-peroxidase, lactoferrin–lactoperoxidase, α-lactalbumin, bovine serum albumin and whey protein concentrate were then studied. While none of these proteins showed any effects on chemotaxis, lactoferrin–lactoperoxidase and whey protein concentrate were found to have an enhancing effect on superoxide production in a dose-dependent manner. Our results provide information on the modulatory role of ruminant milk proteins in inflammatory responses and warrant future investigation.

Differing patterns of neurophysiological abnormalities have been reported in patients with Fisher syndrome. Fisher syndrome is rare, and few series have incorporated prospective serial studies to define the natural history of nerve conduction studies in Guillain-Barré syndrome.In an ongoing prospective study of Guillain-Barré syndrome patients, patients who presented with Fisher syndrome and its spectrum of illness were assessed through serial neurological examinations, nerve conduction studies, and serological testing of IgG against gangliosides and ganglioside complexes.Of the 36 Guillain-Barré syndrome patients identified within 2 years, 17 had features of Fisher syndrome. Serial nerve conduction studies detected significant abnormalities in sensory nerve action potential amplitude in 94% of patients associated with 2 patterns of recovery-non-demyelinating reversible distal conduction failure and axonal regeneration. Similar changes were seen in motor nerves of 5 patients.Patients with the Fisher syndrome spectrum of illness have significant sensory involvement, which may only be evident with serial neurophysiological studies.

Recent declines of bee species have led to great interest in preserving and promoting bee populations for agricultural and wild plant pollination. Many correlational studies have examined the indirect effects of factors such as landscape context and land management practices and found great variation in bee response. We focus here on the evidence for effects of direct factors (i.e., food resources, nesting resources, and incidental risks) regulating bee populations and then interpret varied responses to indirect factors through their species-specific and habitat-specific effects on direct factors. We find strong evidence for food resource availability regulating bee populations, but little clear evidence that other direct factors are commonly limiting. We recommend manipulative experiments to illuminate the effects of these different factors. We contend that much of the variation in impact from indirect factors, such as grazing, can be explained by the relationships between indirect factors and floral resource availability based on environmental circumstances.

Recent declines in managed and feral honey bee populations have greatly increased interest in the current and potential role of wild pollinators in agricultural pollination. Pumpkin (Cucurbita pepo L.) has great potential to be served by wild pollinators because of a reliable and widespread group of bee species that are commonly associated with their flowers, including bumble bees (Bombus spp.), and, in the Americas, two genera of specialist ground nesting bees (Peponapis and Xenoglossa). We examined the effects of several key farm management practices and landscape variables on bee abundance in pumpkin on 20 farms in Virginia and Maryland during summer 2006. We evaluated bee abundance with respect to tillage, irrigation practices, soil properties, natural habitat (forest and grassland), flowering crop, and disturbed areas. Additionally, we examined nest site preference (within or outside of crop areas) of Peponapis pruinosa (Say) at one farm and in a large screenhouse. We found P. pruinosa nesting preferentially within crop areas and near the vines and leaves of their host plant. Although these bees typically place some of their brood cells within tillage depth, we did not find a tillage effect on their abundance at flowers. We found a negative effect of soil clay content (R2 = 0.24, P = 0.03) and a positive effect of irrigation (F1, 15 = 12.2; P < 0.001) on P. pruinosa abundance. Using published data on pollinator visitation requirements, we found wild bee densities were sufficient to fully pollinate all pumpkin flowers on 13-17 of the 20 farms studied.

The surrogate ratio technique is described. New results for neutron induced fission cross sections on actinide nuclei, obtained using this technique are presented. The results benchmark the surrogate ratio technique and indicate that the method is accurate to within 5% over a wide energy range. New results for internal conversion coefficients in triaxial strongly deformed bands in 167Lu are also presented.

Argentine ants, Linepithema humile (Mayr), use mass recruitment foraging, with clumped prey items being retrieved more efficiently than dispersed prey. However, in prior field experiments, granular baits, whether dispensed in containers or broadly scattered, had a similar impact on Argentine ant populations. In laboratory experiments, granular insecticide bait was encountered faster by Argentine ant workers and more granules were initially returned to the colony when the granules were scattered versus clumped. After 2 h, granules from both dispersion patterns were retrieved equally. Our results suggest that Argentine ant colonies adjust their foraging patterns to resources of different quality (prey versus bait). Also, foraging activity patterns for bait in the laboratory are consistent with prior field results demonstrating no efficacy advantages to discrete granular bait placements.

Inbreeding in plants typically reduces individual fitness but may also alter ecological interactions. This study examined the effect of inbreeding in the mixed-mating annual Mimulus guttatus on visitation by pollinators (Bombus impatiens) in greenhouse experiments. Previous studies of M. guttatus have shown that inbreeding reduced corolla size, flower number, and pollen quantity and quality. Using controlled crosses, we produced inbred and outbred families from three different M. guttatus populations. We recorded the plant genotypes that bees visited and the number of flowers probed per visit. In our first experiment, bees were 31% more likely to visit outbred plants than those selfed for one generation and 43% more likely to visit outbred plants than those selfed for two generations. Inbreeding had only a small effect on the number of flowers probed once bees arrived at a genotype. These differences were explained partially by differences in mean floral display and mean flower size, but even when these variables were controlled statistically, the effect of inbreeding remained large and significant. In a second experiment we quantified pollen viability from inbred and self plants. Bees were 37-54% more likely to visit outbred plants, depending on the population, even when controlling for floral display size. Pollen viability proved to be as important as floral display in predicting pollinator visitation in one population, but the overall explanatory power of a multiple regression model was weak. Our data suggested that bees use cues in addition to display size, flower size, and pollen reward quality in their discrimination of inbred plants. Discrimination against inbred plants could have effects on plant fitness and thereby reinforce selection for outcrossing. Inbreeding in plant populations could also reduce resource quality for pollinators, potentially resulting in negative effects on pollinator populations.

Pollen viability ranges substantially among and within plant species, and can be reduced by various factors, including pollution and inbreeding. While it is evident that a reduction in gamete quality reduces the male component of plant fitness, the implications of changes in pollen viability on the nutritional value of pollen for pollinators has not been studied. To test this, we created a greenhouse population of Mimulus guttatus plants that ranged in pollen viability from 17% to 98.5% and related both pollen quantity and pollen protein content to pollen viability. We found that crude protein concentration ranged from 15% to 45% and was positively associated with pollen viability. We also found that pollen mass per flower ranged 5-fold, also positively related to pollen viability. Across experimental plants, there was an 11-fold difference in protein mass per flower between plants of the lowest and highest pollen viabilities. We conclude that conditions that lead to reduced pollen viability, especially early in pollen development, may greatly reduce the awards available to plant pollinators.