Search

The study of foraging behaviour of butterflies has been an important focus among the lepidopterists for years. Although established as invasive weed plant, the role Lantana camara as an important host plant as well as a food plant for the butterfly species is now well-known. The present study aims to interpret the role of morphological variables of the visitor butterflies in relation to their foraging behaviour on Lantana camara. Butterflies with longer proboscis were more efficient in foraging on flowers of Lantana camara than the butterflies with shorter ones, when the species containing proboscis same as or longer than their body length were excluded. Longer relative proboscis length (RPL) have selective advantage for foraging over Lantana camara up to a certain point (RPL = 0.881) and after that larger relative proboscis length often obstructs foraging behaviour as the handling time increases and these butterflies face more resistance against incoming nectar than the others.The residuals (body weight-wing span) also act as important factor.The handling time of the butterflies on Lantana camara shows a negative relationship with the residuals. The findings suggests that in case of Lantana camara as a nectaring plant butterfly species with longer proboscis have selective advantage for exploitation of the resource than the species with shorter ones and plantation of Lantana camara may be useful for conserving the long tongued butterfly species.

Aloe reitzii var. reitzii is a summer-flowering (February–March) succulent, endemic to a restricted range within the heavily transformed grasslands of eastern South Africa. Floral structure and nectar properties suggest bird-pollination. This study investigated the temporal visitation events of birds to this aloe. Extensive camera observations during the 2017 flowering season (23 days) identified both specialist and generalist nectarivorous birds (n = four and five species respectively) as regular diurnal aloe visitors. Malachite Sunbirds (Nectarinia famosa) accounted for 49% of all visits, while Cape Weavers (Ploceus capensis) made up 41% of all visits; these species co-dominate visitation of the specialist and generalist avian feeding guilds respectively. In addition, visitation by each guild was separated temporally to some extent, with generalists mostly visiting early in the day, while specialists dominate afternoon visitation. Nectar volume (overall unbagged mean = 48.67 ± 4.70 µL) and concentration (overall unbagged mean = 10.68 ± 0.21% w/w) remains consistent throughout the day, and are within generalist nectar-feeding bird preferences, which may explain the abundance of Cape Weavers, despite floral morphological traits matching those of specialist nectar feeders. While many summer-flowering aloes are primarily insect- or sunbird-pollinated, Cape Weavers may be supplementing their diets with A. reitzii var. reitzii nectar, and potentially playing a crucial role in pollination.

Strawberry anthocyanins often undergo chemical degradation during storage, which leads to color fading and bioactivity loss. These changes are increased by ascorbic acid, which accelerates anthocyanin degradation. The present study investigated the effect of citric acid as an alternative to ascorbic acid to adjust strawberry nectar pH. Several additions were also used as co-pigment sources to enhance color stability during a five-month dark storage period at ambient temperatures. The results showed that citric acid increased the stability of total and monomeric anthocyanin and reduced the formation of polymeric color. The fortification of the strawberry nectar with 0.2% green tea extract, 3% hot rosella extract, and 0.5% low-methoxyl pectin in the presence of citric acid led to enhance strawberry nectar color, high stability, and reduce anthocyanin degradation.

Abtract The foliar glands of Passiflora are generally known as extrafloral nectaries, which, unlike floral nectaries, are not related to pollination. The present study describes and analyzes the foliar glands found in Passiflora ceratocarpa and Passiflora quadrangularis, in order to confirm their identity as extrafloral nectaries and discuss the taxonomic and ecological implications of these structures. The study material was collected in the metropolitan region of Belem (Brazil) and submitted to standard protocols for the analysis of plant anatomy by light and scanning microscopy, as well as histochemical testing. The extrafloral nectaries of the two species are anatomically very similar, including a multiseriate palisade epidermis, a nectariferous parenchyma consisting of voluminous, thin-walled cells, and predominantly phloematic vascularization. Their chemical composition is also highly similar, and includes sugars, and lipids. Five ant genera were found visiting the two Passiflora species, of which Camponotus was the most abundant, being found on both the study species.

Climate change can disrupt plant-pollinator interactions when shifts in the timing of pollinator activity and flowering occur unequally (i.e., phenological asynchrony). Phenological asynchrony between spring-emerging solitary bees and spring-flowering plants may cause bees to experience food deprivation that can affect their reproductive success. However, the mechanisms underlying the effects of food deprivation on solitary bee reproduction remain unknown. We investigated 1) whether food deprivation caused by phenological asynchrony affects solitary bee reproduction by influencing female lifespan and/or visitation to flowers, and 2) the relationship between the magnitude of asynchrony and bee responses. We simulated phenological asynchrony by depriving emerged female Osmia cornifrons (a spring-active solitary bee species) of nectar and pollen for 0 to 16 days. Following asynchrony treatments, we used flight cages to monitor 1) post-treatment female lifespan, 2) flower visitation, and 3) reproduction (i.e., total offspring, offspring weight, sex ratio). We found that post-treatment female lifespan was not affected by phenological asynchrony treatments, but that flower visitation rate and offspring weight decreased as the magnitude of asynchrony increased. Due to low offspring production and a lack of female offspring across treatments, we were unable to assess the effects of phenological asynchrony on total offspring produced or sex ratio. Findings suggest that post-emergence food deprivation caused by phenological asynchrony may affect offspring size by influencing nest-provisioning rates. In solitary bees, body size influences wintering survival, fecundity, and mating success. Thus, phenological asynchrony may have consequences for solitary bee populations that stem from reduced flower visitation rates, and these consequences may increase as the magnitude of asynchrony increases. Because many wild flowering plants and crops rely on pollination services provided by bees for reproductive success, bee responses to phenological asynchrony may also affect wild plant biodiversity and crop yields.

Long-proboscid fly (LPF) pollination has been recorded in multiple plant lineages in South Africa. However in the large and morphologically diverse genus Erica, evidence for LPF pollination is limited to predictions based upon floral syndromes as well as anecdotal observation and limited citizen science records. Here we use breeding system experiments, pollinator exclusion, remote camera traps, spectral analysis and field observation in the Klein River Mountains, Western Cape Province, South Africa, to demonstrate this mode of pollination in the range-restricted taxon Erica aristata. This species has long narrow corolla tubes with narrow opening and contrasting white and crimson pink petals. Flowers were visited and pollinated exclusively by one long-proboscid fly species, Prosoeca rubicunda (Nemestrinidae) over four years at this study site. Breeding experiments showed that E. aristata is not self-compatible and pollinator exclusion experiments indicate that pollinator visits were required for seed-set. Low nectar volume and moderately high nectar sugar concentration were consistent with other long-proboscid fly-pollinated plant species in the Cape. This study represents the first confirmed instance of long-proboscid fly-pollination in the genus Erica.

Urban green spaces are often subject to intensive management and therefore only provide habitat for very few plant and animal species. Many studies have already proven that less intensive management of near-natural grassland habitats can increase species diversity, for example of butterflies. However, there is still a lack of knowledge as to what extent less intensive management of urban green spaces can promote urban butterfly diversity. Therefore, we examined parameters that determine the number of butterfly species in less maintained or even abandoned urban green spaces. We expected butterfly species richness and observation numbers to be affected by different management regimes. Butterfly surveys were carried out on 56 sites in the city of Hannover, Germany, in three consecutive years. The sites were subject to different management regimes. We explored parameters such as area size, the diversity of nectar plant species and habitat diversity for each site. A total of 34 species were recorded, with a minimum of 0 and a maximum of 17 species per site and year. The extreme drought and heat in 2018 clearly influenced the results of our study and this was reflected in massive decreases of observation numbers for some species. Less intensive management showed preferable effects in comparison to intensive management, but area size and nectar plants were more important factors influencing butterfly species richness and number of observations. Our results suggest that site parameters such as area size, nectar plant species richness or number of habitat types had stronger influences on butterflies than variations of extensive management. We conclude that less intensive urban green space management for good butterfly habitats is not a question of grazing, mowing or temporary abandonment, but instead must aim to increase nectar plant and habitat diversity.

Animals with small nervous systems may be prone to limitations in processing ability when confronted with a diversity of stimuli, especially if these involve multiple sensory modalities. We investigated the effect of the odour of the plant Lantana camara and its dominant volatile compound, β-caryophyllene, on the prey choice decisions of Evarcha culicivora, a jumping spider (Salticidae) that frequently visits L. camara as a site to mate and to obtain nectar. Evarcha culicivora expresses a strong preference for blood-fed female Anopheles mosquitoes as prey. We tested juvenile and adult E. culicivora in experiments involving live prey, lures made from dead prey and virtual prey, when presented with no odour, odour from L. camara and β-caryophyllene. We found that, in the presence of the plant-related odours, E. culicivora's prey preference was no longer expressed. This effect seems to be a consequence of the plant-related odours reducing the extent to which E. culicivora relies on a pre-attack pause and visual fixation routine (‘stationing’) when seeing prey. Stationing may be critical for adequate visual scanning, and thus correct identification of the prey, as we found that the longer the spider was stationed in front of prey before being subjected to a disruption, the more strongly E. culicivora expressed a preference for blood-fed female mosquitoes. This seems to be an unusual example of a specific modulation of visually based prey choice behaviour being mediated by an environmental chemical cue not pertinent to the prey.

Lately, ensuring clear discrimination of the authenticity of natural honey is a concern not only to consumers but also to producers, traders and industries. The intrinsically simple nature of the honey composition, the distinguished health benefits as well as the high price make adulteration and falsification of the honey very common and the detection of authenticity very difficult. Samar honey (n = 59) and Talh honey (n = 64) produced from two species of Acacia trees (Acacia tortilis and Acacia gerrardii Benth, respectively) in different countries, including the United Arab Emirates, Saudi Arabia, Oman, and Yemen, has been studied by applying Multivariate Data Analysis. The discrimination is based on the official chemical quality parameters that inform about the nectary sources, including glucose, fructose, sucrose content, total reducing sugar, moisture content, acidity and diastase activity. Results show that the total reducing sugar, glucose and fructose were the most important positive loading descriptors that influence the quality of Samar and Talh honey. In addition, most of the Talh honey samples clustered at the top of the hierarchy, while Samar honey samples clustered at the bottom. The Multivariate Data Analysis indicates that the acidity and diastase activity are the most effective characteristics influencing the floral and geographical discrimination of both types of honey. This is the first study in the GCC area to discriminate between Samar and Talh honey using Multivariate Data Analysis by applying the principal component analysis and hierarchical cluster analysis. The Multivariate Data Analysis can be a helpful method to differentiate between Talh and Samar honey.

Heterotrigona itama is a stingless bee species from Meliponini tribe. The bee collects nectar, pollen and resin to produce honey, bee bread, and propolis. The bee is also known to visit and collect nectar from various types of flowers but there are limited studies on why this species of bee prefers to visit certain types of flowers. This study was conducted to identify the nectar concentration in selected flowers favoured by H. itama and the relationship between the bee and the morphology of the flowers. Nectar was obtained from different species of flowers and the concentrations were measured using a digital refractometer. The tube length of each flower species and the tongue length of the bees were also measured. The results revealed that flowers preferred by H. itama have high nectar concentrations. The tube lengths of the preferred flowers were between 2.0 and 4.0 mm, which is compatible with the tongue length of the bee. This study revealed that both nectar concentration and flower morphology are important factors for the bees in choosing their food sources. The results from this study will benefit the beekeepers in the identification of flowers that should be planted in their farms to improve stingless bee beekeeping activities. Understanding the relationship between the bees and their flower preferences could also help us to understand the importance of conserving both the bee colonies and the various species of flowering plants to ensure the sustainability of flora and fauna in the ecosystem.

The frequency and outcome of biotic interactions commonly vary with environmental conditions, even without changes to community composition. Yet the drivers of such environmentally-mediated change in biotic interactions are poorly understood, limiting our ability to predict how environmental change will impact communities. Studying nectar robbery by stingless bees ofOdontonema cuspidatum(Acanthaceae) in a coffee agroecosystem, we documented a temporally consistent difference in nectar robbing intensity between anthropogenic and seminatural habitats. Plants growing in coffee fields (anthropogenic habitat) experienced significantly more nectar robbery than plants growing in forest fragments (seminatural habitat). Using a combination of field surveys and manipulative experiments, we found that nectar robbery was higher in coffee fields primarily due to environmental effects on a) neighborhood floral context and b)O. cuspidatumfloral traits. This led to both preferential foraging by nectar robbers in coffee fields, and to changes in foraging behavior onO. cuspidatumthat increased robbery. Nectar robbery significantly reduced fruit set inO. cuspidatum. These results suggest that the effects of anthropogenic environmental change on species traits may be more important than its effect on species density in determining how interaction frequency and outcome are affected by such environmental change.

Microbes (fungi, bacteria and viruses) living within flowers are hypothesized to affect pollination. We evaluate current support for this idea at each stage of the pollination process. Evidence to date is convincing that microbes influence pollinator attraction, but data are heavily weighted toward bumblebees and the effects of nectar yeasts. Effects of microbes on the efficacy of pollinator visits is understudied and variable outcomes from field studies suggest quality of pollinator visits, not only quantity, are likely involved. The effect of microbes on pollen performance is underappreciated. Beyond the effect of pathogenic viruses, the impacts of pollen-transmitted endophytic microbes on pollen viability or tube growth are unknown but could affect the outcome of pollen receipt. Future research integrating microbes into pollination should broaden taxonomic diversity of microbes, pollinators and plants and the processes under study.

Puddling in butterflies is an essential physiological phenomenon, by which they gain mineral nutrients required for their reproductive success and flight. The preference given to the puddling by butterflies has been analysed by two hypotheses: butterflies puddle when there is a scarcity of nutritional resource in one hypothesis and competition with other males to increase their probability of mating in the other. In the present investigation, an attempt has been made to verify these hypotheses through experimental evidences in the butterfly Papilio polytes, in which only males are known to puddle. Our investigation revealed the significance of puddling as an alternative source of nutrition in the absence of nectar. However, increase in the number of males in a given vicinity with constant number of females enhances the puddling activity in males. This shows the importance of puddling as a distinct competitive behaviour by which male improves their chances of mating. Additionally, in both cases the puddling is drastically regulated by the environmental temperature. Males prefer to puddle at a temperature ranging from 26 °C to 28 °C, which is considered as optimum for puddling activity. Further, the fecundity and longevity of imago are completely unaffected by puddling activity. All these results are in good agreement with the existing hypotheses and show the behavioural significance of puddling in butterflies.

Honey is a powerful antimicrobial agent with a wide range of effects. Various components contribute to the antibacterial efficacy of honey: the sugar content; polyphenol compounds; hydrogen peroxide; 1,2-dicarbonyl compounds; and bee defensin-1. All of these elements are present at different concentrations depending on the source of nectar, bee type, and storage. These components work synergistically, allowing honey to be potent against a variety of microorganisms including multidrug resistant bacteria and modulate their resistance to antimicrobial agents. The effectiveness and potency of honey against microorganisms depends on the type of honey produced, which is contingent on its botanical origin, the health of the bee, its origin, and processing method. The application of antibiotics with honey yielded better antimicrobial potential and synergistic effects were noted against biofilms. In medicine, honey has been used in the treatment of surface wounds, burns, and inflammation, and has a synergistic effect when applied with antibiotics. Tissue repair is enhanced by the low pH of honey (3.5–4): causing a reduction in protease activity on the wound site, elevating oxygen release from hemoglobin and stimulating fibroblast and macrophage activity. Furthermore, H2O2 has antiseptic effects, and it disinfects the wound site and stimulates production of vascular endothelial growth factor. The use of honey will clean wounds or burn areas from free radicals and reduces scarring and contractures. The anti-inflammatory and antibacterial potential of honey will keep the injured area moist and as such prevents it from deterioration and fibrosis. Honey can promote fast healing and reduce scarring and is very convenient for plastic surgery. Skin maceration is protected by honey due to its high osmolarity and because it keeps the injury moist. In non-infected areas, honey still reduced pain and inflammation. In general, the use of honey in medical settings has reduced economic loss and provided proven economic benefits by lowering direct costs in comparison to conventional treatments and by using less antibiotics, faster healing and less hospitalization stay. This review is intended to provide an overview of the antibacterial activities of honey and its applications.

A long developmental period in animals is often needed to learn skills for adult reproduction and survival, including feeding behaviour. The nocturnal Javan slow loris, Nycticebus javanicus, is unusual in that it consumes a specialized diet of difficult to extract resources, as well as disperses up to a year after sexual maturity. Here, we examined the ontogeny of its feeding behaviour to understand whether learning to feed on difficult resources, including by co-feeding, is related to delayed dispersal. We collected feeding and proximity data on developing and adult wild slow lorises at a long-term field site in Cipaganti, West Java from 2012 to 2018. To determine whether acquisition of insects, exudates, nectar and flowers varied by age, we ran logistic generalized additive mixed models. We found that intake of insects and exudates occurred significantly more in the early stages, and feeding on nectar significantly more in the later stages, of development. Co-feeding occurred for all food types, with insects showing the most co-feeding events during early development, and co-feeding on exudates remaining high throughout development. Social learning via co-feeding is a potentially important factor in transmission of dietary information from older individuals, including siblings and parents, to young slow lorises. Differences between immature and adult diets levelled off after sexual maturity and before average dispersal. Together these factors suggest that the period required to learn to forage on difficult items could help explain the delayed dispersal patterns seen in mammals with similar foraging strategies.

Microbial residents of floral nectar must survive in a carbohydrate-rich yet seemingly nitrogen-poor environment. A new study shows that Acinetobacter spp., common nectar-inhabiting bacteria, differentially induce the pollen commonly found in nectar to germinate and burst, releasing nutrients for microbial growth.

Summary Plant secondary metabolites found in floral nectar can affect the behaviour of pollinating insects, but how these changes benefit plants directly is little understood. An experimental study with bumblebees shows that recalling a caffeine-enhanced odour memory can increase flower visitation.

Most plant species are pollinated by animals, mainly insects, who adjust their foraging behaviour to the spatial distribution of rewards. Any changes in rewards of individual plants could then affect pollen dispersal at the level of plant patches or populations. Such change in floral rewards often results from infection by plant pathogens, for example by anther smuts (i.e. no pollen and reduced nectar in diseased flowers). Here, we tested the hypothesis that the infection of plant populations by anther smuts affects the pattern of pollen dispersal. We investigated the patterns of pollen dispersal in experimental arrays of potted plants differing in the presence of diseased plants and the degree of plant spatial aggregation. We tracked pollen dispersal using a fluorescent dye powder as a pollen analogue, while we simultaneously observed pollinator foraging behaviour. We found that the dispersal of the pollen analogue increased in the presence of diseased plants in experimental arrays, but this effect was strongly dependant on plant spatial aggregation. The parallel observations of pollinator behaviour suggest that this pattern resulted from pollinator discrimination against diseased plants and increased movement in arrays with intermingled diseased plants, provided that plant clusters were close to each other. Our study indicates that pollinators respond to diseased plants in a similar way as to healthy plants with low rewards. Consequently, diseased plants should be treated not only as a potential source of infection but also as a factor influencing pollen dispersal in plant populations.

Individuals sometimes exhibit striking constancy to a single behaviour even when they are capable of short-term behavioural flexibility. Constancy enables animals to avoid costs such as memory constraints, but can also inflict significant opportunity costs through behaviour–environment mismatch. It is unclear when individuals should exhibit behavioural constancy and which types of costs most strongly influence such behaviour. We use a case in which individuals within a population exhibit more than one handling tactic for a single food type to investigate whether costs associated with switching among tactics constrain expression of intra-individual variation. Using wild bumble bees (Bombus spp.) that feed on nectar through flower openings (legitimate visits) or through holes at the base of flowers (robbing), we asked three questions. (1) Do individual bees exhibit tactic constancy within and across foraging bouts? (2) Are individuals willing to switch their food-handling tactics? (3) Is constancy in food-handling tactics maintained by costs associated with switching tactics? We measured energetic costs in addition to handling times. We found that bees freely foraging in meadows were highly constant to a single food-handling tactic both within and across bouts. However, experiments with individual captive bees showed that these bees were willing to switch tactics and experienced minimal costs in doing so. Thus, switching costs do not drive the observed constancy in food-handling tactics of bumble bees within and across foraging bouts.

The loss of flower-rich habitat in agricultural landscapes is a key factor contributing to bumble bee declines across Europe and North America. Yet, agricultural intensification has not only altered flower abundance in the landscape, but also affected when flowers are available during the season (e.g., mass-flowering crops). While we know that both total pollen and nectar as well as temporal availability can impact bumble bee colony success (growth and reproductive output), we have yet to understand how these two factors combined might manifest. We designed an experiment to decouple the effects of total food abundance and its temporal availability on bumble bee microcolony development by exposing them to either constant or pulsed food availability at a high and low ration level. Microcolonies provided constant, high-rations of food grew the most, while those fed variable, but high rations gained less mass over the course of the experiment. Regardless of the temporal presentation of food, microcolonies fed low rations gained little mass over the experiment. Reproductive output was greatest in microcolonies fed high rations, regardless of the temporal availability of food, while those given low rations produced on average 27% fewer drones. This study highlights the importance of food abundance for both colony growth and reproduction, regardless of how food is presented (e.g., constantly or in a pulse). Together, these results indicate that increasing total food abundance will have the greatest, positive impact on colony fitness.

Intraspecific morphological variation fundamentally influences individual resource exploitation. In plant–pollinator systems, variation in floral morphologies and pollinator mouthparts may affect pollinators' resource use. This relationship has frequently been studied across species, but hardly ever at the intraspecific level in natural circumstances. We studied flower visits of clouded Apollo butterflies, Parnassius mnemosyne. (1) We investigated whether proboscis (mouthpart) length variability influenced individual nectar plant choice within a single population. We hypothesized that flower depths would constrain butterflies’ flower visits via their proboscis lengths. (2) We studied whether individual proboscis length constrained feeding on the sticky catchfly, Silene viscaria, a species with ample nectar and the deepest corolla among the plants visited. We hypothesized that individuals observed visiting S. viscaria had longer proboscides than those not observed on this nectar source. We captured clouded Apollos, then measured proboscis length. We surveyed the population daily, identified marked individuals and recorded feeding on nectar plant species. We compared proboscis length to the flower depth of the six most-visited nectar plants and investigated whether individual visits on flowering plants were related to proboscis length. We found large intrapopulation variation in proboscis length, and high intra- and interspecific variation in flower depth of the six nectar plants. Flower depth of S. viscaria largely overlapped with proboscis length, while the other five plants had shorter flowers. Individuals with longer proboscides visited S. viscaria flowers more often than those with short proboscides. These results indicate the importance of morphological variation in the interaction between plants and pollinators. We provide the first evidence that individual variation in mouthpart length affects lepidopteran foraging in natural circumstances. We suggest that interactions between species in plant–pollinator systems are partially based on individually different continuous traits, rather than on well-defined discrete traits of different taxa as implied by the pollination syndrome hypothesis.

Anthropophilic female mosquitoes are well known for their strong attraction to human hosts, but plant nectar is a common energy source in their diets. When sugar sources are scarce, female mosquitoes of some species can compensate by taking larger and more frequent blood meals. Male mosquitoes are exclusively dependent on plant nectar or alternative sugar sources. Plant preference is likely driven by an innate attraction that may be enhanced by experience, as mosquitoes learn to recognize available sugar rewards. Nectar-seeking involves the integration of at least three sensory systems: olfaction, vision and taste. The prevention of vector-borne illnesses, the determination of the mosquitoes' ecological role, and the design of efficient sugar-baited traps will all benefit from understanding the molecular basis of nectar-seeking.

Background: Bee bread is a product of the fermentation of a mixture of pollen, nectar and bee saliva that is inoculated by a wide range of bacteria and yeasts necessary for fermentation after stora ...

Wind is an important yet understudied environmental influence on foraging behaviour. We investigated the direct and indirect effects of wind on foraging worker honey bees, Apis mellifera. Bees were trained to an array of artificial flowers providing nectar rewards in a location sheltered from natural wind. To examine the direct effect, fans produced four different wind speeds between 0 and 3 m/s at three different flower spacings: 5 cm (flowers touching) and 10 cm and 20 cm (flowers not touching). To examine the indirect effect of wind moving flowers, flowers were moved 10 cm at three frequencies between 50 and 110 cycles/min at zero wind speed. We recorded the number of successful flower visits, time spent flying, search time on a flower and hesitancy to take off. Bees visited significantly fewer flowers with increasing wind speed which was caused by a significant increase in hesitancy to take off. This difference in flower visits between wind speeds was highest at the 20 cm spacing. Flower movement had no effect on foraging rate; however, there was a significant positive relationship between flower movement and the total time spent flying. This was counterbalanced by a significant reduction in time spent searching for the nectary after landing on a flower at the higher flower frequencies. Our results suggest that it is the direct effect of wind on hesitancy to take off that has the greatest effect on honey bee foraging rate.

A plant–pollinator system with pesticides is considered, in which the plant or plant’s seeds are treated by pesticides and the food (e.g., pollen and nectar) produced by plant is contaminated. The effect of pesticides is characterized by a toxin-determined functional response, which is a modification of the traditional Beddington–DeAngelis functional response through explicitly including a reduction in the consumption of food by the pollinator due to pesticides. Dynamics of the model demonstrate basic mechanisms by which the toxicity results in reduction of pollinators and leads to extinction of pollination mutualisms. It is also shown that varying the toxicity level could make the dynamics transition between uniform persistence, bi-stability, tri-stability and species’ extinction in a smooth fashion. Moreover, a detailed bifurcation analysis of the system reveals a rich array of novel behaviors including double saddle-node bifurcation and double transcritical bifurcation, which exhibits important biological implications in the complex dynamics of pollination mutualisms under pesticides.

Background Grit is used by birds mainly for grinding hard food items but can also serve a nutritional role as a source of minerals. Ingestion of grit by birds has been documented primarily in species that feed on seeds and invertebrates. Although feeding mainly on nectar and small arthropods, hummingbirds also ingest grit, but why they do so is unclear. We quantified the number of grit particles in the stomachs of six species of hummingbirds during an annual cycle in a seasonal ecosystem of West Mexico. Methods We compared the number of grit particles in the stomachs of different hummingbird species (Mexican Violetear Colibri thalassinus, Amethyst-throated Mountaingem Lampornis amethystinus, White-eared Hummingbird Basilinna leucotis, Rivoli’s Hummingbird Eugenes fulgens, Broad-tailed Hummingbird Selasphorus platycercus, and Rufous Hummingbird S. rufus), and between sex and age categories during the different seasons of a year. To determine if grit was used to grind ingested arthropods, we examined the relationships between the number of grit particles, the biomass of arthropods ingested, and their chitin content. Results Although species did not differ in the number of grit particles in their stomachs, we found that grit was mostly ingested by female individuals, with only one male of one species (Mexican Violetear) presenting grit in its stomach. We also found that female hummingbirds had grit in their stomachs during the rainy and the cold-dry season (June–February) but not during the warm-dry season (March–May). Our analyses revealed no relationship between the number of grit particles and the amount of ingested arthropods and arthropod chitin content. However, high grit consumption was related to wasp ingestion on Mexican Violetears. Conclusions Our results indicate that grit is used mainly by female hummingbirds. The seasonal variation in the ingestion of grit by female individuals suggests that it can be used to meet mineral requirements related to breeding; however, this topic needs further exploration. Additionally, the use of grit was proportionally higher in juvenile individuals, suggesting it is used for grinding arthropods during a period of fast development.

When flowers provide nectar, they can count on visits, and potential pollen transport, by many kinds of nectar-drinking animals. Yet, some flowers instead offer fatty oils that certain specialized bees gather with their forelegs. A recent study reveals how such a switch occurred and may have contributed to the formation of a new species.

Cases of honey poisoning have been reported widely, meaning there is a need for methods that detect "mad honey" or honey contaminated with plant-derived toxins to protect human health. In this study, we compared whole flower extracts and honey from Tripterygium wilfordii Hook. f. (TwHf) and Macleaya cordata (Willd) R. Br (McRB) using QuEChERS (quick, easy, cheap, effective, rugged, and safe) and ultra-high-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UHPLC/Q-TOF-MS). The results revealed several compounds common to whole flowers and honey samples. Triptolide and protopine were selected as potential markers for identifying "mad honeys" from these plants. The developed method can easily detect different honey varieties that were spiked with 5% TwHf and McRB honey samples. Additionally, 90 commercial honey samples were analyzed and determined as free from contamination. The method described in this report could be useful for studies on honey from other poisonous nectar and pollen plants.

Forests and woodlands are considered as the most important sources of honey bee forage in many European countries with several tree species providing nectar and/or honeydew flow. Slovenia boasts with high number of beekeepers and high colony count per square kilometer. We have investigated the impact of availability of natural resources and colony density on honey yield. Data presented here were collected on 57 locations with monitor hives, equipped with scales, over years 2011–2016. Locations were selected according to site vegetation, ensuring identified source of nectar or honeydew flow. The source of the flow was recorded and verified by contract beekeeper. We investigated (1) the relationship between abundance of the flow source expressed as the quantity of growing stock and net mass gain of the monitor colony during the flow and (2) the relationship between colony density expressed as the number of colonies against growing stock volume and net mass gain of the monitor colonies. We found an asymptotic exponential relationship between colony mass gain and growing stock of the species, providing flow. The exception was the spruce where the relationship was determined as linear (k = 0.023 ± 0.009). The τ of the exponential approach in the case of acacia flow was 9.8 ± 5.6 and in case of linden flow 6.6 ± 3.9 (mean ± SE). Colony density then determined the colony mass gain due to the flow. In cases of acacia, linden and spruce flow we have determined the relationship between colony density and mass gain as decaying exponential (τ = 283.9 ± 60.6, τ = 1.6 ± 0.4 and 3.0 ± 1.3, respectively, all mean ± SE). Combined linden/chestnut flow was fitted best with linear equation (k = −0.08 ± 0.019). Most likely, another variable should be used in the case of spruce flow: population of dew-producing insects. Periodical monitoring of eight acacia locations show differences in mass gain between years, thus allowing prediction of colony densities which guarantee profit: these locations are determined as those with colony density less than 50 hives/103 m3 growing stock gained more than 10 kg/hive in 83% of cases, regardless of the year. Our results indicate that a cap on the total number of colonies at one location should be considered to maximize beekeepers’ profit.

Ongoing debate about specialisation vs generalisation in plant–pollinators interactions highlights the reliability of pollination syndrome traits as predictors of the primary pollinator of a species. The South African Watsonia knysnana (Iridaceae) is a case in point as its tubular corolla is consistent with ornithopilous floral traits to attract sunbirds (specialist nectarivore passerines) but the range of colours exhibited covers syndromes that would predict both birds and insects. From exclusion experiments we identified sunbirds as the most effective pollinators of W. knysnana with honeybees playing a minor role, if any. In addition, the nectar properties (concentration and volume) conform to plants pollinated mainly by specialist nectarivorous birds.

A geographical discrimination of honey is an important prerequisite for quality and authenticity control. Here, we present a method based on an NMR-metabolomic analysis of organic extracts for a geographical discrimination of commercial European acacia honeys found on the Italian market. All 234 analysed samples show the characteristic 1H NMR profile of acacia (Robinia pseudoacacia) honey. However, a PLS2-DA model revealed variations among production zones allowing the successful geographical differentiation with a 100% of overall correct classification rate. Moreover, a PLS2 model is able to predict the proportions in binary blends of Italian and Eastern European acacia honeys. The geographical distinction and the possibility to characterize the content of blends derive from different markers content originating from minor nectar contributions of the acacia-accompanying flora.

In addition to breast milk, several mammals feed their offspring with primary food items. This provisioning can offer both energetic and informational benefits: young might use parentally provided food as a source of nutrients, but also as a valuable option to socially learn about adults' food. For bats, there are only very few and partially anecdotal reports of adults feeding their pups with primary food, and there is also a lack of information about social learning processes during ontogeny. In the present study, we provide experimental evidence that lactating flower-visiting bats (Glossophaga soricina) provide regurgitated nectar via mouth-to-mouth feeding behaviour to their pups. After licking at their mothers' slightly opened mouth, pups defecated a marker substance that was exclusively available in the mothers' nectar diet. We additionally investigated associated informational benefits by testing for a social transmission of dietary preferences. We experimentally induced a dietary preference for specifically flavoured nectars to mothers with non-volant pups. Subsequently, after pups became volant, we tested their dietary preferences in a choice experiment. However, we found no experimental evidence that pups adopted the preferences of their mothers.

Trade-offs are considered a major factor in the evolution of ecological specialization, as organisms can rarely specialize on more than one niche. Here we ask whether flowers can be specialized for more than one pollinator group. We studied an outcrossing plant, Aloe kraussii (Asphodelaceae), whose floral morphology is intermediate between that of exclusively bird- and exclusively insect-pollinated aloes. Previous field experiments showed that bees effectively pollinate A. kraussii; while sunbirds are frequent visitors their effectiveness as pollinators was unknown, especially as their long bills prevent head feathers—the normal location of pollen transfer by birds—from touching A. kraussii's relatively short anthers and stigmas. We tested whether sunbirds can pollinate A. kraussii, and whether this might be facilitated by flowers' narrow corolla opening, which could increase pollen transfer via narrow sunbird bills. Aviary experiments showed that a Malachite sunbird's bill can successfully pick up and deposit A. kraussii pollen, so long-billed sunbirds can be effective pollinators despite the apparent mismatch between bill and corolla length. Flowers with experimentally widened corolla openings experienced lower pollen removal and deposition by sunbirds than unmanipulated flowers with narrow openings. Aloe kraussii's floral morphology therefore enables dual specialization on two divergent pollinator guilds; short corollas facilitate bee pollination by enabling access to nectar, while narrow corolla openings facilitate pollen transfer via sunbird bills.

Understanding how animals learn is crucial to interpreting animal behaviour. Flower-visiting insects, such as bees and parasitoids, are excellent animal models to study visual and olfactory learning, including memory phenomena. The diversity of resources flower-visiting insects exploit predisposes them to learn and remember the colours, shapes and odours associated with rewarding experiences (e.g. flowers), allowing them to focus on the most rewarding resources. Recent research has shown that nectar-living microbes release volatile organic compounds (VOCs) that contribute to overall flower scent. Nevertheless, little is known about the extent to which nectar microbiota mediate insect learning of floral preferences. In this study, we investigated whether VOCs produced by nectar microbes serve as a learning cue to parasitoids and how long any developed preference is maintained. Experiments were performed using the generalist aphid parasitoid Aphidius ervi and three nectar yeasts, including the nectar specialist Metschnikowia reukaufii and the generalist species Hanseniaspora uvarum and Sporobolomyces roseus. Results showed that naive parasitoids had an innate preference for nectar fermented by the nectar specialist M. reukaufii, but not by the other two yeasts which had either a neutral (H. uvarum) or deterrent (S. roseus) effect. When parasitoids were conditioned with yeast-fermented nectar, they were strongly attracted to their odours 2 and 24 h after conditioning, but not after 48 h. Furthermore, when parasitoids were conditioned to one yeast-fermented nectar, they also showed increased attraction to other yeast-fermented nectars. This generalization suggests that their learning ability may have broader ecological consequences. However, this generalized response to other yeast VOCs lasted for only 2 h. We conclude that parasitoids show conditioned responses to the scent of yeast-fermented nectar, and yeasts, therefore, may play an important but understudied role in shaping their foraging behaviour.

This study was conducted at the apiary of the Beekeeping Research Section at the Sakha Agricultural Research Station, ARC, Kafrelsheikh, and other apiaries in Kafrelsheikh province, during two successive years 2015 and 2016. The study aimed to survey nectar and pollen floral resources in Kafrelsheikh province. Ninty seven plant species belonging to 33 families were recorded as nectar sources, and 82 plant species belonging to 36 families were recorded as pollen sources during the whole year. The largest amount of monthly trapped pollen was obtained during May followed by August. It can be concluded that, beekeepers in Kafrelsheikh province can harvest good honey yield at the end of blooming seasons of citrus (Citrus spp.) during March and April, Egyptian clover (Trifolium alexandrinum L.) during May and June, loofah (Luffa aegyptiaca Mill.) during June to October, cotton (Gossypium spp.) during July and August, and banana (Musa spp.) during August and September. They also, could be trapping pollen loads collected from faba bean (Vicia faba L.) and flax (Linum usitatissimum L.) during January to March, date palm (Phoenix dactylifera L.) during March and April, Egyptian clover during May and June, summer seed watermelon (Citrullus lanatus var. colothynthoides L.) during June and July, loofah and maize (Zea mays L.) during June to November. Keywords: Flora, Honeybee, Kafrelshiekh, Nectar, Pollen

Although moths and butterflies are closely related, they tend to respond to different floral cues for foraging and thus select for different suites of floral traits. Shifts between moth and butterfly pollination in the same plant clade provide an opportunity to assess the traits that are required to impart a shift between these pollination systems. The orchid genus Bonatea consists mostly of night-scented moth-pollinated taxa, but here we document a butterfly pollination system in Bonatea cassidea, a century after Mansel Weale's initial observations of butterflies carrying pollinaria of this taxon in South Africa were communicated to the Linnean Society by Charles Darwin. We recorded visits by a number of species of butterflies from the family Hesperiidae and Pieridae, but contrary to Weale, we found that the majority of pollinaria were firmly affixed between the palpi and not on the sternum. Removal of pollinaria from flowers during the day, but not at night, suggested that moths do not contribute to pollination, despite the white flower colouration. Floral traits found in B. cassidea but not its moth-pollinated congeners include diurnal anthesis, scent emission which is weak in the day and virtually absent at night, and the production of small amounts of relatively dilute sucrose-rich nectar in short spurs. These features are consistent with those expected for butterfly-pollinated plants in general. This study represents the first detailed report of butterfly-pollination in Bonatea and one of very few cases of orchid pollination by pierid butterflies.

Honey is a nutritious natural sweetener from honey bee-collected nectar from a variety of flowers. The health benefits and high value of honey, however, have motivated fraudulent acts of honey adulteration by either a direct or secondary inclusion of cheaper sweeteners. Therefore, stringent quality controls must be in place to ensure authenticity of honeys while safeguarding the wellbeing of consumers. To detect adulterants in honey, researchers are continually exploring rapid, sensitive and efficient recognition systems using chemometric-integrated spectroscopic techniques. These techniques have garnered significant attention of researchers for use in categorizing and detecting honey, as well as the incorporated adulterants. This paper provides an all-inclusive overview on the challenges for effective detection and quantification of a wide-ranging sugary adulterants in honey, worldwide. The advantages and drawbacks of diversified analytical techniques including nuclear magnetic resonance spectroscopy, infrared and Raman spectroscopy, sensor-based methods and chromatography with different sample pre-treatments for distinguishing the adulterants in honey are also discussed. This article also compares and deliberates on the performance among the reported techniques to detect adulterants in honey, specifically highlighting the concepts used for detection, along with the modifications that were made which led to their success and failure.

Knowledge about indirect defences that mediate the ecological interactions between plants and their beneficial and harmful insects are needed to better incorporate pest resistance traits in breeding programs. “Top-down” pest control by natural enemies has not been considered in most plant breeding strategies and, in many cases, beneficial interactions of crops with the third trophic level have been reduced through breeding processes. Extrafloral nectaries (EFNs) are plant structures that provide indirect defences to plants through nectar rewards attracting arthropods that may act as predators of pests. Recent studies have demonstrated that EFNs may play an important role in herbivore suppression in agricultural systems. The main objectives of this study were to quantify the leaf extrafloral nectar production of cotton plants, to identify natural enemies of crop pests visiting these EFNs, and to assess the biological control and occurrence of various cotton pests. To address these objectives, we performed both greenhouse and field experiments in which we compared three wild varieties of cotton plants with EFNs, two cultivated varieties with EFNs and two nectariless varieties. Results showed that wild cotton varieties produced greater quantity of nectar per leaf than cultivated varieties. In addition, wild varieties bearing EFNs enhanced the diversity of natural enemies (especially ants) which could, in turn, increase biological control under certain conditions. However, the association between the community of insects visiting EFNs and pest suppression was not clear and depended on the pest species. Indirect defences associated to EFN need to be better explored to enhance selection of pest-resistant cotton cultivars.

Honeybees (HB) are strongly attracted to lychee flowers and serve as the main pollen vector in most lychee orchards throughout the world. Despite precise protocols for managing HB in Israeli lychee orchards, we suspected that the full pollination potential of the orchards was not being achieved and that yields could be increased. Since bumblebees (BB) forage in harsh weather and at lower temperatures than HB, in previous studies we questioned if adding BB to HB in apple and pear orchards would increase fruit set and yield. Encouraged by the important results, we examined this approach in lychee in the present work. The experiments were conducted for three years, resulting in a significant increase in lychee fruit set and yield. Our observations revealed that BB contribute to lychee pollination not only because they are active in conditions that HB are not, but also because HB collect mainly nectar from the lychee flowers and barely contact the reproductive organs, while BB collect mainly pollen and hence pollination increases. As a result of this work, since 2018 10 BB hives per hectare have been introduced into many lychee orchards in Israel in addition to the standard 2.5 HB hives per hectare.

Gul, Osman/0000-0003-1620-4246; YILMAZ, Volkan Arif/0000-0001-5039-4026; Atalar, Ilyas/0000-0001-8560-0010 WOS: 000457144400008 PubMed: 30711107 The effect of high pressure homogenization (HPH) on physical and bioactive properties of rosehip nectar was investigated. Rosehip nectar has a sedimentation problem while waiting on the market shelf during the sale, for solving this problem, nectars were passed 1, 2 and 3 times through 75, 100 and 125 MPa pressures. Mean particle size decreased as pressure and pass number increased (p < 0.05), whereas zeta potential did not change (p > 0.05). Microstructural images revealed that HPH treatment disrupted the cells and caused to release of cell materials to serum. HPH treatment increased the.E values (from 2.48 to 6.03). HPH treated samples showed no sedimentation during storage for 15 days. All samples showed shear thinning behavior and were characterized as weak gel network (G' > G ''). Total phenolic content and ascorbic acid results were decreased by HPH treatments due to increasing outlet temperatures of product, however, antioxidant capacity of nectars increased after treatment due to increasing total carotenoid content. This study indicated that HPH treatment could solve the sedimentation problem during shelf life with minimally affecting bioactive and physical properties of rosehip nectar.

In recent years, the impact of Plant Protection Products (PPPs) on insect pollinator decline has stimulated significant amounts of research, as well as political and public interest. PPP residues have been found in various bee-related matrices, resulting in governmental bodies worldwide releasing guidance documents on methods for the assessment of the overall risk of PPPs to different bee species. An essential part of these risk assessments are PPP residues found in pollen and nectar, as they represent a key route of exposure. However, PPP residue values in these matrices exhibit large variations and are not available for many PPPs and crop species combinations, which results in inaccurate estimations and uncertainties in risk evaluation. Additionally, residue studies on pollen and nectar are expensive and practically challenging. An extrapolation between different cropping scenarios and PPPs is not yet justified, as the behaviour of PPPs in pollen and nectar is poorly understood. Therefore, this review aims to contribute to a better knowledge and understanding of the fate of PPP residues in pollen and nectar and to outline knowledge gaps and future research needs. The literature suggests that four primary factors, the crop type, the application method, the physicochemical properties of a compound and the environmental conditions have the greatest influence on PPP residues in pollen and nectar. However, these factors consist of many sub-factors and initial effects may be disguised by different sampling methodologies, impeding their exact characterisation. Moreover, knowledge about these factors is ambiguous and restricted to a few compounds and plant species. We propose that future research should concentrate on identifying relationships and common features amongst various PPP applications and crops, as well as an overall quantification of the described parameters; in order to enable a reliable estimation of PPP residues in pollen, nectar and other bee matrices.

The nectar provision hypothesis posits that biological control by parasitoids can be enhanced by providing supplemental nectar in the vicinity of cropland. The rationale for this hypothesis is that parasitoid longevity and fecundity can be greatly enhanced by sugar meals and that many agricultural areas are devoid of naturally occurring sugar sources. While some experimental field studies have produced results supporting the nectar provision hypotheses, many others have failed to show that supplemental nectar can improve biological control by parasitoids. I propose that some parasitoids may engage in medium- or long-range dispersal upon feeding on nectar and thus not contribute to local parasitism adjacent to flower plantings. If true, this could help to explain some of the negative results of nectar supplementation experiments. I further propose that certain conditions favor nectar-induced dispersal and discuss four of these here: (i) the risk of self-superparasitism, (ii) the risk of density-dependent hyperparasitism, (iii) benefits of ‘spreading the risk’ of catastrophic mortality and (iv) the risk of inbreeding among parasitoid offspring.

Viola banksii of the eastern Australian and Tasmanian sect. Erpetion produces exclusively chasmogamous flowers, unlike most other temperate taxa of Viola which additionally produce obligatory self-pollinated cleistogamous flowers. This study explored flower structure and nyctinastic flower movements (temporal flower closure), the correlation of the timing of nyctinastic movements with stigma receptivity, and self-compatibility of flowers. Petal movement in day/night cycles was documented by two cameras. Floral morphology, anther protuberance anatomy, stigma receptivity, and pollen tube growth were examined using scanning electron microscopy, fluorescent microscopy, histochemical and sectioning techniques. Diurnal petal movements that cause flowers to be open during the day and closed during the night were documented in V. banksii. Chasmogamous flower colour, fragrance, anterior petal venation, and the indurated green area at the base of the anterior petal are all likely to play roles for pollinator attraction. Unlike most other Viola species, the anther protuberances do not function as nectaries. The flowers offer pollinators no nectar reward. The short time of stigma receptivity (2–3 days) of individual flowers limits opportunities for insect visitation and cross-pollination. Night-closed flowers of V. banksii appear to facilitate self-pollination. Self-compatibility was confirmed by tracking the pollen tube growth from the stigma to the ovule in spontaneous and hand self-pollinated flowers. Over the floral phenological cycle, nyctinasty coincides in time with stigma receptivity and, hence, the ability of self-pollination. We discovered that the same chasmogamous flower of V. banksii can cross-pollinate while open during the day, but self-pollinate while closed during the night (i.e. acting as a cleistogamous-like flower). Several floral characters indicate that V. banksii exhibits a pollination deceit strategy. Such a pollination system has not been described elsewhere in Viola.

Despite the increasing number of studies dealing with interaction networks in the last few years, there is still a lack of knowledge about how their structural organization are affected by changes in binary or weighted data. To fill this gap, we collected ants foraging on plants with extrafloral nectaries in 10 sites within the Brazilian Amazon to evaluate if the generality, vulnerability, nestedness, and modularity observed in these ant-plant networks could be affected by changes in data categories. Specifically, we used three matrices built by different data categories: (i) binary data (i.e., presence or absence of an interaction between a plant and an ant species); (ii) frequency data (i.e., number of times in which a plant species interacted with an ant species); and (iii) abundance data (i.e., number of workers of an ant species recorded foraging on a plant species). In general, when analyzing different matrix categories, we observed changes in the structural organization of the studied ant-plant interaction networks. Surprisingly, however, at the species level, both categories of weighted data (i.e., frequency and abundance data) seem to be equally appropriate for describing the role of ant species. Our results highlight the need to expand the discussion about data categories in ecological interaction studies to understand how different data categories may lead to different ecological interpretations.

Neonicotinoid insecticides have been used in a wide range of crops through seed treatment, soil and foliar applications and a large database exists on both their lethal and sub-lethal effects on honey bees under controlled laboratory conditions. However, colony-level studies on the effects of neonicotinoids in field studies are limited, primarily due to their complexity and the resources required. This paper reports the combined results of two large-scale colony-feeding studies, each with 6 weeks of continuous dosing of 12 colonies per treatment (24 control) to 12.5, 25, 37.5, 50 or 100 ng thiamethoxam/g sucrose solution. Exposure continued beyond dosing with residues present in stored nectar and bee-bread. The studies were conducted in an area with limited alternative forage and colonies were required to forage for pollen and additional nectar The studies provide colony-level endpoints: significant effects (reductions in bees, brood) were observed after exposure to the two highest dose rates, colony loss occurred at the highest dose rate, but colonies were able to recover (2–3 brood cycles after the end of dosing) after dosing with 50 ng thiamethoxam/g sucrose. No significant colony-level effects were observed at lower dose rates. The data reported here support the conclusions of previous colony-level crop-based field studies with thiamethoxam, in which residues in pollen and nectar were an order of magnitude below the colony-level NOEC of 37.5 ng thiamethoxam/g sucrose. The feeding study data are also compared to the outcomes of regulatory Tier 1 risk assessments conducted using guidance provided by the USA, Canada, Brazil and the EU regulatory authorities. We propose an adaptation of the European chronic adult bee risk assessment that takes into account the full dataset generated in laboratory studies while still providing an order of magnitude of safety compared with the colony feeding study NOEC.

Made available in DSpace on 2019-10-06T16:06:25Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-03-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Thiamethoxam (TMX) is a neurotoxic insecticide widely used for insect pest control. TMX and other neonicotinoids are reported to be potential causes of honey bee decline. Due to its systematic action, TMX may be recovered in pollen, bee bread, nectar, and honey, which make bees likely to be exposed to contaminated diet. In this study, we used immunolabeling to demonstrate that sublethal concentrations of TMX decrease the protein levels of synapsin in the mushroom bodies (MBs) and the antennal lobes (ALs) of pupae and newly emerged worker bees that were exposed through the food to TMX during the larval phase. A decrease in the synapsin level was observed in the MBs of pupae previously exposed to 0.001 and 1.44 ng/µL and in newly emerged bees previously exposed to 1.44 ng/µL and no changes were observed in the optical lobes (OLs). In the ALs, the decrease was observed in pupae and newly emerged bees exposed to 1.44 ng/µL. Because the MBs and ALs are brain structures involved in stimuli reception, learning, and memory consolidation and because synapsin is important for the regulation of neurotransmitter release, we hypothesize that exposure to sublethal concentrations of TMX during the larval stage may cause neurophysiological disorders in honey bees. Universidade Estadual Paulista (UNESP) Centro de Estudos de Insetos Sociais (CEIS) Instituto de Biociências Campus Rio Claro Universidade Federal de São Carlos (UFSCar) Departamento de Biologia Laboratório de Ecotoxicologia e Biomarcadores em Animais (LEBA) Campus Sorocaba Universidade Federal de São Carlos (UFSCar) Departamento de Ciências da Natureza Matemática e Educação Centro de Ciências Agrárias Campus Araras Universidade Estadual Paulista (UNESP) Centro de Estudos de Insetos Sociais (CEIS) Instituto de Biociências Campus Rio Claro FAPESP: 2012/01498-0 FAPESP: 2012/13370-8 FAPESP: 2012/50197-2

Introducing nectar-producing plants to green roofs and other urban green infrastructure has been attempted to support pollinator activities. Green roofs can be drought-prone, placing limitations on the success of plant growth and nectar production in the absence of irrigation. Plant species differ greatly in water usage patterns, so companion planting with low and high water users has been proposed to increase performance of high water use species, including species important for urban pollinators. Additionally, crassulacean acid metabolism (CAM) plants such as Sedum tend to have low water usage and are reported to improve health condition of neighbors. However, Sedum species differ in morphological and physiological traits such as leaf shapes and the speed at which they switch to CAM, resulting in water usage differences during drought that could affect neighboring plants. This study quantifies the effects of companion planting with CAM plants (Sedum album, Sedum kamtschaticum) on nectar-producing plants (Fagopyrum esculentum, Trifolium repens), focusing on target plant growth form and leaf traits of neighboring Sedum. The health condition of F. esuculentum and soil water contents were improved significantly when they were planted together with S. album, which has small leaves and rapid CAM induction. Therefore, suppression of evapotranspiration of neighboring CAM plants could have positive effects on erect growth form nectar species. In contrast, the health condition of T. repens, which shows prostrate growth, was not affected by neighboring CAM plant species. Judging from these results, growth characteristics including leaf traits of neighboring Sedum and growth forms of the target plants could be important factors determining the effects of companion planting in urban green infrastructure.

Spiders are generalist predators adapted to consume a wide range of prey although their ability to exploit non-prey foods such as pollen, nectar, and honeydew has been referred but less studied. In this work, we investigated the effect of different non-prey food items (Glucose at 0.5 M; aphid honeydew; black scale honeydew; a mixture of glucose 0.5 M, phenylalanine 0.1 mM, proline 0.1 mM, and tryptophan 0.1 mM; honey at 10%, and pollen at 10%) on the survival of immature spiders of two functional groups represented by Haplodrassus rufipes (ground hunters) and Synema globosum (ambushers), and their feeding choices, in laboratory experiments. The overall survival of both species fed on non-prey foods significantly increased compared to individuals fed on water. The black-scale honeydew was the best food for H. rufipes increasing longevity up to 117 days. The highest survival reached by S. globosum was observed when fed on a mixture of glucose 0.5 M and three amino acids. When different non-prey food items were offered together, the exploring rate was significantly higher for H. rufipes than for S. globosum. H. rufipes chose to feed on honey whereas S. globosum chose the mixture treatment. The most chosen food items corresponded with those that provided the highest longevities in both species. Our results suggest that spiders could search, recognize and actively select the most beneficial non-prey food. Habitat management practices such as maintaining weed strips in the crop may provide these valuable supplementary food resources within agroecosystems contributing for biological pest control. info:eu-repo/semantics/publishedVersion

For more than six decades, bumblebee death, which mainly occurs in August, has been assumed to be associated with intake of presumed toxic nectar from linden trees (Tilia spp.), a hypothesis which has been sustained by observations of a significant number of dead bumblebees under these trees during their flowering season. Several theories exist in current literature to account for these observations. The nectar has been assumed to contain compound(s) toxic to the bumblebees including the monosaccharide mannose, which cannot be metabolized by bumblebees. The presence of toxic compounds such as the alkaloid nicotine or pesticides of anthropogenic origin has also been indicated. However, none of the above suggested compounds have hitherto been properly characterized from the nectar. In the current paper we report on characterization of the composition of nectar of linden trees, under which a significant number of dead bumblebees were observed. The structure determinations were performed by selective 1D TOCSY NMR and extensive applications of 2D NMR spectroscopy. The nectar of the linden flowers was readily available in significant amounts during the entire period when dead bumblebees were observed under these trees. The nectar only contained non-toxic sugars such as α-glucopyranose, β-glucopyranose, sucrose, fructose and minor amounts of xylose. The nectar did not contain mannose, nor alkaloids or pesticides. Initial toxicity studies using brine shrimp lethality assay showed that the nectar did not exhibit any toxic effects even at concentrations higher than 1 mg/ml dry weight, providing disproving evidence against the assumption of the nectar's toxic character.

The foraging preferences of Apis mellifera for flower depend on the content of sugar and amino acid in nectar. To determine the factor in nectar that attracts honeybee in field, we investigated the foraging rate of honeybee, fruit set, relationship between the foraging behavior of honeybee and contents of nectar in different Asian pear cultivars (‘Niitaka’ and ‘Whangkeumbae’), which do not produce pollen. The foraging rate of honeybee on ‘Whangkeumbae’ was 2 times higher than that on ‘Niitaka’ and the fruit set of ‘Whangkeumbae’ was 1.5 times higher than that of ‘Niitaka’. ‘Whangkeumbae’ exhibited 3.7 times higher nectar secretion than ‘Niitaka’. The total sugar content in the nectar of ‘Whangkeumbae’ was 1.1–1.7 times higher than that in the nectar of ‘Niitaka’, and this difference was significant. Furthermore, the content of glucose, fructose, and sucrose in the nectar of ‘Whangkeumbae’ was higher than that in the nectar of ‘Niitaka’. In particular, the content of sucrose in ‘Whangkeumbae’ was 1.3–3.2 times higher than that in ‘Niitaka’; sucrose is known to be the most preferred sugar by honeybee. Among the 20 amino acids detected in both cultivars, the content of Nine amino acids was significantly different. The content of phenylalanine and glycine (which are preferred by honeybee) in ‘Whangkeumbae’ was 1.4–2.4 times higher than that in ‘Niitaka’. In contrast, the content of asparagine (which is not preferred by honeybee) in ‘Niitaka’ was 1.1–2.4 times higher than that in ‘Whangkeumbae’. Among the sugars in nectar, sucrose exhibited the highest relationship with the number of foraging bees, followed by glucose and fructose. Among the amino acids, phenylalanine presented the highest correlation with the number of foraging bees, followed by glycine and alanine. The results suggest that honeybees prefer ‘Whangkeumbae’ over ‘Niitaka’ because of the difference in the amino acid and sugar content in the nectar of pear cultivars.