Publications

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spatial reorientation by geometry in bumblebees.human and non-human animals are capable of using basic geometric information to reorient in an environment. geometric information includes metric properties associated with spatial surfaces (e.g., short vs. long wall) and left-right directionality or 'sense' (e.g. a long wall to the left of a short wall). however, it remains unclear whether geometric information is encoded by explicitly computing the layout of surface geometry or by matching images of the environment. view-based spatial encoding ...201222624033
study of local anaesthetics--part 196 formulation of the local anaesthetic heptacaine into hydrogel on the basis of chitosan.the study aimed to formulate the local anaesthetic heptacaine into hydrogels on the basis of chitosan. the gel-creating compounds used included natural polymers --three different types of chitosan, namely those of a medium molecular weight, from the shells of shrimp, and from the bumblebees species bombus terrestris. the prepared hydrogels were evaluated on the basis of their rheological properties and drug liberation. from the point of drug liberation and flow properties, the optimal gel compos ...201222536655
miniature-dispenser-based bioassay to evaluate the compatibility of powder formulations used in an entomovectoring approach.entomovectoring as a plant protection strategy demands the design of an appropriate bioassay to assess the risks of potential side effects of the powder formulations in the dispenser towards the vectoring insect. this study reports on the development of a laboratory miniature-dispenser-based bioassay. this bioassay system was used to investigate the compatibility of five model products, prestop-mix, signum, kaolin, wheat flour and cellulose, with the bumblebee, bombus terrestris l.201222328246
using diagnostic radioentomology for non-invasive observations of colonies of the bumblebee, bombus terrestris.bumblebees have been the focus of a broad range of scientific research due to their behavior, social life, and a number of other intriguing traits. current methods for examining their nest structure, such as natal cells and contents of storage cells, are destructive in nature because the cells need to be opened for physical inspections. this research describes how the internal structures of the artificial nests of the bumblebee bombus terrestris l. (hymentoptera: apidae) were non-invasively view ...201223421622
social context and reproductive potential affect worker reproductive decisions in a eusocial insect.context-dependent decision-making conditions individual plasticity and is an integrant part of alternative reproductive strategies. in eusocial hymenoptera (ants, bees and wasps), the discovery of worker reproductive parasitism recently challenged the view of workers as a homogeneous collective entity and stressed the need to consider them as autonomous units capable of elaborate choices which influence their fitness returns. the reproductive decisions of individual workers thus need to be inves ...201223251701
the abundance and pollen foraging behaviour of bumble bees in relation to population size of whortleberry (vaccinium uliginosum).habitat fragmentation can have severe effects on plant pollinator interactions, for example changing the foraging behaviour of pollinators. to date, the impact of plant population size on pollen collection by pollinators has not yet been investigated. from 2008 to 2010, we monitored nine bumble bee species (bombus campestris, bombus hortorum s.l., bombus hypnorum, bombus lapidarius, bombus pascuorum, bombus pratorum, bombus soroensis, bombus terrestris s.l., bombus vestalis s.l.) on vaccinium ul ...201223209721
radar tracking and motion-sensitive cameras on flowers reveal the development of pollinator multi-destination routes over large spatial scales.central place foragers, such as pollinating bees, typically develop circuits (traplines) to visit multiple foraging sites in a manner that minimizes overall travel distance. despite being taxonomically widespread, these routing behaviours remain poorly understood due to the difficulty of tracking the foraging history of animals in the wild. here we examine how bumblebees (bombus terrestris) develop and optimise traplines over large spatial scales by setting up an array of five artificial flowers ...201223049479
differential sensitivity of honey bees and bumble bees to a dietary insecticide (imidacloprid).currently, there is concern about declining bee populations and the sustainability of pollination services. one potential threat to bees is the unintended impact of systemic insecticides, which are ingested by bees in the nectar and pollen from flowers of treated crops. to establish whether imidacloprid, a systemic neonicotinoid and insect neurotoxin, harms individual bees when ingested at environmentally realistic levels, we exposed adult worker bumble bees, bombus terrestris l. (hymenoptera: a ...201223044068
effects of fastac 50 ec on bumble bee bombus terrestris l. respiration: dge disappearance does not lead to increasing water loss.sublethal effects of pesticides in insects can be observed through physiological changes, which are commonly estimated by metabolic rate and respiratory patterns, more precisely by the patterns of discontinuous gas-exchange (dge) cycles. the aim of the present research was to study the effect of some low concentrations of fastac 50 ec on the cycles of co(2) release and respiratory water loss rates (wlr) in bumble bee bombus terrestris l. foragers. bumble bees were dipped into 0.004% and 0.002% f ...201222960306
visual attention in a complex search task differs between honeybees and bumblebees.mechanisms of spatial attention are used when the amount of gathered information exceeds processing capacity. such mechanisms have been proposed in bees, but have not yet been experimentally demonstrated. we provide evidence that selective attention influences the foraging performance of two social bee species, the honeybee apis mellifera and the bumblebee bombus terrestris. visual search tasks, originally developed for application in human psychology, were adapted for behavioural experiments on ...201222723491
illumination preference, illumination constancy and colour discrimination by bumblebees in an environment with patchy light.patchy illumination presents foraging animals with a challenge, as the targets being sought may appear to vary in colour depending on the illumination, compromising target identification. we sought to explore how the bumblebee bombus terrestris copes with tasks involving flower colour discrimination under patchy illumination. light patches varied between unobscured daylight and leaf-shade, as a bee might encounter in and around woodland. using a flight arena and coloured filters, as well as one ...201222675177
effects of imidacloprid, a neonicotinoid pesticide, on reproduction in worker bumble bees (bombus terrestris).bumble bees are important pollinators whose populations have declined over recent years, raising widespread concern. one conspicuous threat to bumble bees is their unintended exposure to trace residues of systemic neonicotinoid pesticides, such as imidacloprid, which are ingested when bees forage on the nectar and pollen of treated crops. however, the demographic consequences for bumble bees of exposure to dietary neonicotinoids have yet to be fully established. to determine whether environmenta ...201222614036
size-related variation in protein abundance in the brain and abdominal tissue of bumble bee workers.female bumble bee workers of the same species often show a profound body size variation that is linked to a division of labour. large individuals are more likely to forage whereas small individuals are more likely to perform in-nest activities. a higher sensory sensitivity, stronger circadian rhythms as well as better learning and memory performances appear to better equip large individuals for outdoor activities compared to their smaller siblings. the molecular mechanisms underlying worker func ...201222568679
neonicotinoid pesticide reduces bumble bee colony growth and queen production.growing evidence for declines in bee populations has caused great concern because of the valuable ecosystem services they provide. neonicotinoid insecticides have been implicated in these declines because they occur at trace levels in the nectar and pollen of crop plants. we exposed colonies of the bumble bee bombus terrestris in the laboratory to field-realistic levels of the neonicotinoid imidacloprid, then allowed them to develop naturally under field conditions. treated colonies had a signif ...201222461500
conspecific and heterospecific information use in bumblebees.heterospecific social learning has been understudied in comparison to interactions between members of the same species. however, the learning mechanisms behind such information use can allow animals to be flexible in the cues that are used. this raises the question of whether conspecific cues are inherently more influential than cues provided by heterospecifics, or whether animals can simply use any cue that predicts fitness enhancing conditions, including those provided by heterospecifics. to d ...201222347479
mite species inhabiting commercial bumblebee (bombus terrestris) nests in polish greenhouses.nests of social insects are usually inhabited by various mite species that feed on pollen, other micro-arthropods or are parasitic. well-known negative effects of worldwide economic importance are caused by mites parasitizing honeybee colonies. lately, attention has focused on the endoparasitic mite locustacarus buchneri that has been found in commercial bumblebees. however, little is known of other mites associated with commercial bumblebee nests. transportation of commercial bumblebee colonies ...201222270110
Purification and inflammatory edema induced by two PLA(2) (Anch TX-I and Anch TX-II) from sea anemone Anthothoe chilensis (Actiniaria: Sagartiidae).The Anch TX-I and II PLA(2) were purified from Anthothoe chilensis (Lesson, 1830) from the extract of the anemone after only two chromatographic step using molecular exclusion chromatography (Sephadex G-75) and reverse phase HPLC on µ-Bondapak C18 column. Both PLA(2) showed a molecular mass of ~14kDa determined by MALDI-TOF mass spectrometry and showed a high catalytic activity (data not showed). Although homologous with mammalian or snake venom group I PLA(2)s, Anch TX-I and II is sufficiently ...201222100907
gut microbiota instead of host genotype drive the specificity in the interaction of a natural host-parasite system.specific interactions between parasite genotypes and host genotypes (g(p) × g(h)) are commonly found in invertebrate systems, but are largely lacking a mechanistic explanation. the genotype of invertebrate hosts can be complemented by the genomes of microorganisms living on or within the host ('microbiota'). we investigated whether the bacterial gut microbiota of bumble bees (bombus terrestris) can account for the specificity of interactions between individuals from different colonies (previousl ...201222765311
ecological effects on gut bacterial communities in wild bumblebee colonies.1. animal hosts harbour diverse and often specific bacterial communities (microbiota) in their gut. these microbiota can provide crucial services to the host such as aiding in digestion of food and immune defence. however, the ecological factors correlating with and eventually shaping these microbiota under natural conditions are poorly understood. 2. bumblebees have recently been shown to possess simple and highly specific microbiota. we here examine the dynamics of these microbiota in field co ...201222708631
robustness of the outcome of adult bumblebee infection with a trypanosome parasite after varied parasite exposures during larval development.the outcome of defence by the invertebrate immunity has recently been shown to be more complex than previously thought. in particular, the outcome is affected by biotic and abiotic environmental variation, host genotype, parasite genotype and their interaction. knowledge of conditions under which environmental variation affects the outcome of an infection is one important question that relates to this complexity. we here use the model system of the bumblebee, bombus terrestris, infected by the t ...201222487556
pervasiveness of parasites in pollinators.many pollinator populations are declining, with large economic and ecological implications. parasites are known to be an important factor in the some of the population declines of honey bees and bumblebees, but little is known about the parasites afflicting most other pollinators, or the extent of interspecific transmission or vectoring of parasites. here we carry out a preliminary screening of pollinators (honey bees, five species of bumblebee, three species of wasp, four species of hoverfly an ...201222347356
factors influencing nosema bombi infections in natural populations of bombus terrestris (hymenoptera: apidae).bumblebees are of profound ecological importance because of the pollination services they provide in natural and agricultural ecosystems. any decline of these pollinators is therefore of great concern for ecosystem functioning. increased parasite pressures have been discussed as a major factor for the loss of pollinators. one of the main parasites of bumblebees is nosema bombi, an intracellular microsporidian parasite with considerable impact on the vitality of the host. here we study the effect ...201222349145
safety and acquisition potential of metarhizium anisopliae in entomovectoring with bumble bees, bombus terrestris.in the context of integrated pest management with biological control and reduced pesticide use, dissemination of entomopathogenic fungi with insects has the potency to protect crops and specifically their flowers against pests and diseases. but before implementation of such entomovectoring system, a measurement of risks of the microbial biocontrol agent toward the vectoring insect is crucial. the essential contributions of this project are that 1) exposure of bumble bees, bombus terrestris (l.) ...201323448041
emerging dangers: deadly effects of an emergent parasite in a new pollinator host.there is growing concern about the threats facing many pollinator populations. emergent diseases are one of the major threats to biodiversity and a microsporidian parasite, nosema ceranae, has recently jumped host from the asian to the western honeybee, spreading rapidly worldwide, and contributing to dramatic colony losses. bumblebees are ecologically and economically important pollinators of conservation concern, which are likely exposed to n. ceranae by sharing flowers with honeybees. whilst ...201323816821
the role of desaturases in the biosynthesis of marking pheromones in bumblebee males.bumblebee males (hymenoptera) produce species-specific labial gland secretions called marking pheromones (mps). mps generally consist of terpenoids and fatty-acid-derived aliphatic compounds with various chain lengths predominantly containing one or no double bonds. the unsaturated fatty-acid-derived mp components were hypothesized to be produced by fatty acid desaturases (fads) that exhibit diverse substrate specificities. to address this hypothesis, we isolated and functionally characterized f ...201323727612
yeasts in nectar of an early-blooming herb: sought by bumble bees, detrimental to plant fecundity.through their effects on physicochemical features of floral nectar, nectar-dwelling yeasts can alter pollinator behavior, but the effect of such changes on pollination success and plant reproduction is unknown. we present results of experiments testing the effects of nectar yeasts on foraging patterns of captive and free-ranging bumble bees, and also on pollination success and fecundity of the early-blooming, bumble bee-pollinated helleborus foetidus (ranunculaceae). under controlled experimenta ...201323691645
specific recognition of reproductive parasite workers by nest-entrance guards in the bumble bee bombus terrestris.the impact of social parasites on their hosts' fitness is a strong selective pressure that can lead to the evolution of adapted defence strategies. guarding the nest to prevent the intrusion of parasites is a widespread response of host species. if absolute rejection of strangers provides the best protection against parasites, more fine-tuned strategies can prove more adaptive. guarding is indeed costly and not all strangers constitute a real threat. that is particularly true for worker reproduc ...201324321042
social regulation of maternal traits in nest-founding bumble bee (bombus terrestris) queens.during the nest-founding phase of the bumble bee colony cycle, queens undergo striking changes in maternal care behavior. early in the founding phase, prior to the emergence of workers in the nest, queens are reproductive and also provision and feed their offspring. however, later in the founding phase, queens reduce their feeding of larvae and become specialized on reproduction. this transition is synchronized with the emergence of workers in the colony, who assume the task of feeding their sib ...201323966589
bumblebee visual search for multiple learned target types.visual search is well studied in human psychology, but we know comparatively little about similar capacities in non-human animals. it is sometimes assumed that animal visual search is restricted to a single target at a time. in bees, for example, this limitation has been evoked to explain flower constancy, the tendency of bees to specialise on a single flower type. few studies, however, have investigated bee visual search for multiple target types after extended learning and controlling for prio ...201323948481
queen control of a key life-history event in a eusocial insect.in eusocial insects, inclusive fitness theory predicts potential queen-worker conflict over the timing of events in colony life history. whether queens or workers control the timing of these events is poorly understood. in the bumble-bee bombus terrestris, queens exhibit a 'switch point' in which they switch from laying diploid eggs yielding females (workers and new queens) to laying haploid eggs yielding males. by rearing foundress queens whose worker offspring were removed as pupae and sexing ...201323637392
genetic variability of the neogregarine apicystis bombi, an etiological agent of an emergent bumblebee disease.the worldwide spread of diseases is considered a major threat to biodiversity and a possible driver of the decline of pollinator populations, particularly when novel species or strains of parasites emerge. previous studies have suggested that populations of introduced european honeybee (apis mellifera) and bumblebee species (bombus terrestris and bombus ruderatus) in argentina share the neogregarine parasite apicystis bombi with the native bumblebee (bombus dahlbomii). in this study we investiga ...201324324696
qualitatively different immune response of the bumblebee host, bombus terrestris, to infection by different genotypes of the trypanosome gut parasite, crithidia bombi.insects have a complex and highly successful immune system that responds specifically to different types of parasites. different genotypes of a parasite species can differ in infectivity and virulence; which is important for host-parasite co-evolutionary processes, such as antagonistic, fluctuating selection. such coevolution obviously requires a genetic basis, but little is known about how hosts immunologically respond to different genotypes. the common european bumblebee bombus terrestris is i ...201324055962
immune gene expression in bombus terrestris: signatures of infection despite strong variation among populations, colonies, and sister workers.ecological immunology relies on variation in resistance to parasites. colonies of the bumblebee bombus terrestris vary in their susceptibility to the trypanosome gut parasite crithidia bombi, which reduces colony fitness. to understand the possible origin of this variation in resistance we assayed the expression of 28 immunologically important genes in foraging workers. we deliberately included natural variation of the host "environment" by using bees from colonies collected in two locations and ...201323869212
characterization of neutral lipase bt-1 isolated from the labial gland of bombus terrestris males.in addition to their general role in the hydrolysis of storage lipids, bumblebee lipases can participate in the biosynthesis of fatty acids that serve as precursors of pheromones used for sexual communication.201324260337
detoxification and stress response genes expressed in a western north american bumble bee, bombus huntii (hymenoptera: apidae).the hunt bumble bee (bombus huntii greene, hymenoptera: apidae) is a holometabolous, social insect important as a pollinator in natural and agricultural ecosystems in western north america. bumble bees spend a significant amount of time foraging on a wide variety of flowering plants, and this activity exposes them to both plant toxins and pesticides, posing a threat to individual and colony survival. little is known about what detoxification pathways are active in bumble bees, how the expression ...201324330608
variability in bumblebee pollination buzzes affects the quantity of pollen released from flowers.buzz-pollination is a plant strategy that promotes gamete transfer by requiring a pollinator, typically bees (hymenoptera: apoidea), to vibrate a flower's anthers in order to extract pollen. although buzz-pollination is widespread in angiosperms with over 20,000 species using it, little is known about the functional connection between natural variation in buzzing vibrations and the amount of pollen that can be extracted from anthers. we characterized variability in the vibrations produced by bom ...201323188056
bumblebees (bombus terrestris) and honeybees (apis mellifera) prefer similar colours of higher spectral purity over trained colours.differences in the concentration of pigments as well as their composition and spatial arrangement cause intraspecific variation in the spectral signature of flowers. known colour preferences and requirements for flower-constant foraging bees predict different responses to colour variability. in experimental settings, we simulated small variations of unicoloured petals and variations in the spatial arrangement of colours within tricoloured petals using artificial flowers and studied their impact ...201323224278
repression and recuperation of brood production in bombus terrestris bumble bees exposed to a pulse of the neonicotinoid pesticide imidacloprid.currently, there is concern about declining bee populations and some blame the residues of neonicotinoid pesticides in the nectar and pollen of treated crops. bumble bees are important wild pollinators that are widely exposed to dietary neonicotinoids by foraging in agricultural environments. in the laboratory, we tested the effect of a pulsed exposure (14 days 'on dose' followed by 14 days 'off dose') to a common neonicotinoid, imidacloprid, on the amount of brood (number of eggs and larvae) pr ...201324224015
the influence of pigmentation patterning on bumblebee foraging from flowers of antirrhinum majus.patterns of pigmentation overlying the petal vasculature are common in flowering plants and have been postulated to play a role in pollinator attraction. previous studies report that such venation patterning is significantly more attractive to bee foragers in the field than ivory or white flowers without veins. to dissect the ways in which venation patterning of pigment can influence bumblebee behaviour, we investigated the response of flower-naïve individuals of bombus terrestris to veined, ivo ...201323420080
de novo biosynthesis of sexual pheromone in the labial gland of bumblebee males.de novo biosynthesis of male sex pheromone from two bumblebee species (bombus terrestris and bombus lucorum) was studied by using in vitro incubations of labial glands (lgs) with radioactive [1,2-(14)c]acetate and deuterated [d(3)]acetate. the labeled substrate was incorporated into several types of compounds, such as terpenic alcohols, fatty acids, esters, and hydrocarbons. a similar incubation of [1,2-(14)c]acetate with fat bodies (fb) led to the formation of fatty acids, triacylglycerols (tag ...201323325667
too much work, not enough tarsi: group size influences bombus impatiens (hymenoptera: apidae) worker reproduction with implications for sublethal pesticide toxicity assessments.as bumble bees may routinely forage on pesticide-treated plants, it is imperative to apply pesticides that pose minimal risk. identifying such reduced-risk pesticides requires toxicity tests using biologically relevant and standardized exposure methods. our goal was to develop a functional and reliable queen-less micro-colony method for determining the sublethal effects of pesticides on bombus impatiens cresson, a species for which further toxicity assessments are needed. originally developed us ...201323786039
ca²⁺/calmodulin-dependent protein kinase ii in the cockroach periplaneta americana: identification of five isoforms and their tissues distribution.calcium/calmodulin-dependent protein kinase ii (camkii) is a key kinase that transduces ca²⁺ signals into downstream effects acting on a range of cellular processes in nervous system and muscular tissues. in insects, different camkii isoforms have been reported in drosophila melanogaster, apis florae, bombus terrestris, and bombus impatiens but little is known on the organization and tissue-specific expression of these isoforms with the exception of drosophila. the present study reports the clon ...201323740573
characterisation of a functional allatotropin receptor in the bumblebee, bombus terrestris (hymenoptera, apidae).allatotropins (ats) are multifunctional neuropeptides initially isolated from the tobacco hornworm, manduca sexta, where they were found to stimulate juvenile hormone synthesis and release from the corpora allata. ats have been found in a wide range of insects, but appear to be absent in drosophila. the first at receptor (atr) was characterised in 2008 in the lepidopteran bombyx mori. since then atrs have been characterised in coleoptera and diptera and in 2012, an at precursor gene was identifi ...201323968772
recruitment to forage of bumblebees in artificial low light is less impaired in light sensitive colonies, and not only determined by external morphological parameters.bumblebees of bombus terrestris are essential pollinators in natural and managed ecosystems. their foraging ability relies on the individual morphology, task allocation within the colony, and external factors, such as light intensity. the foraging activities of commercial bumblebees can sometimes be impaired, especially in the artificial and weak light intensities of greenhouses at high altitudes. here we investigated whether the eagerness (or willingness) to forage of bumblebee colonies in diff ...201323834824
learning of geometry and features in bumblebees (bombus terrestris).bumblebees (bombus terrestris) were trained to find one of the four exit holes located in the corners of an enclosed environment with a distinctive geometry (a rectangular cage). panels located at the corners provided nongeometric, featural cues. between trials bumblebees were passively disoriented to disable dead reckoning. when tested after removal of the panels, bumblebees reoriented using the residual information provided by the geometry of the cage. when tested after removal of only the two ...201323815593
patterns of genetic and reproductive traits differentiation in mainland vs. corsican populations of bumblebees.populations on islands often exhibit lower levels of genetic variation and ecomorphological divergence compared to their mainland relatives. while phenotypic differentiation in characters, such as size or shape among insular organisms, has been well studied, insular differentiation in quantitative reproductive traits involved in chemical communication has received very little attention to date. here, we investigated the impact of insularity on two syntopic bumblebee species pairs: one including ...201323755263
unravelling the mechanisms of trapline foraging in bees.trapline foraging (repeated sequential visits to a series of feeding locations) is a taxonomically widespread but poorly understood behavior. investigating these routing strategies in the field is particularly difficult, as it requires extensive tracking of animal movements to retrace their complete foraging history. in a recent study, we used harmonic radar and motion-triggered video cameras to track bumblebees foraging between artificial flowers in a large open field. we describe how all bees ...201323750293
assessment of gustatory responses to different sugars in harnessed and free-moving bumblebee workers (bombus terrestris).for bumblebee colony survival, sugar responses are crucial as nectar is the main carbohydrate source and flower choice is likely determined by sugar composition. this study used a bioassay both with harnessed and with free-moving workers of the bumblebee bombus terrestris to study the gustatory response to the 3 major plant sugars by both groups. in harnessed workers of b. terrestris, a concentration of 5.5% of fructose and glucose was required to induce the proboscis extension reflex in 50% of ...201323599218
membrane filtering properties of the bumblebee (bombus terrestris) photoreceptors across three spectral classes.filtering properties of the membrane form an integral part of the mechanisms producing the light-induced electrical signal in insect photoreceptors. insect photoreceptors vary in response speed between different species, but recently it has also been shown that different spectral photoreceptor classes within a species possess diverse response characteristics. however, it has not been quantified what roles phototransduction and membrane properties play in such diversity. here, we use electrophysi ...201323571735
dietary chlorantraniliprole suppresses reproduction in worker bumblebees.pollinators such as the bumblebee, bombus terrestris, fulfil a crucial role in agriculture. in this context, tests were conducted with the insecticide chlorantraniliprole (coragen®) as a model compound active on the ryanodine receptor of insects.201323564706
bumblebee calligraphy: the design and control of flight motifs in the learning and return flights of bombus terrestris.many wasps and bees learn the position of their nest relative to nearby visual features during elaborate 'learning' flights that they perform on leaving the nest. return flights to the nest are thought to be patterned so that insects can reach their nest by matching their current view to views of their surroundings stored during learning flights. to understand how ground-nesting bumblebees might implement such a matching process, we have video-recorded the bees' learning and return flights and a ...201323447668
detection and learning of floral electric fields by bumblebees.insects use several senses to forage, detecting floral cues such as color, shape, pattern, and volatiles. we report a formerly unappreciated sensory modality in bumblebees (bombus terrestris), detection of floral electric fields. these fields act as floral cues, which are affected by the visit of naturally charged bees. like visual cues, floral electric fields exhibit variations in pattern and structure, which can be discriminated by bumblebees. we also show that such electric field information ...201323429701
serine protease from midgut of bombus terrestris males.a serine protease was isolated from midguts of the bumblebee male bombus terrestris by a combination of precipitation procedures with column chromatography. the purified enzyme exhibited two bands with molecular masses of 25 and 26 kda as determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis. these bands showed a proteolytic activity in zymography assay. midgut enzymes showed optimum proteolytic activity at ph 9 and 35°c using n-succinyl-l-alanyl-l-alanyl-l-prolyl-l-phenyl-alan ...201323303700
wax lipids signal nest identity in bumblebee colonies.the signalling functions of cuticular lipids, particularly cuticular hydrocarbons, have gained considerable attention in social insect communication. information transfer between individuals by means of these substances has been examined extensively. however, communication with cuticular lipids is not limited to inter-individual recognition. cuticular compounds can also have a signalling function in the nest environment. workers of the bumblebee bombus terrestris leave cuticular lipid traces, so ...201323288373
daily changes in ultraviolet light levels can synchronize the circadian clock of bumblebees (bombus terrestris).endogenous circadian clocks are synchronized to the 24-h day by external zeitgebers such as daily light and temperature cycles. bumblebee foragers show diurnal rhythms under daily light:dark cycles and short-period free-running circadian rhythms in constant light conditions in the laboratory. in contrast, during the continuous light conditions of the arctic summer, they show robust 24-h rhythms in their foraging patterns, meaning that some external zeitgeber must entrain their circadian clocks i ...201323281715
isolation and properties of flight muscle mitochondria of the bumblebee bombus terrestris (l.).this report describes the isolation procedure and properties of tightly coupled flight muscle mitochondria of the bumblebee bombus terrestris (l.). the highest respiratory control index was observed upon oxidation of pyruvate, whereas the highest respiration rates were registered upon oxidation of a combination of the following substrates: pyruvate + malate, pyruvate + proline, or pyruvate + glutamate. the respiration rates upon oxidation of malate, glutamate, glutamate + malate, or succinate we ...201324228879
can winter-active bumblebees survive the cold? assessing the cold tolerance of bombus terrestris audax and the effects of pollen feeding.there is now considerable evidence that climate change is disrupting the phenology of key pollinator species. the recently reported uk winter activity of the bumblebee bombus terrestris brings a novel set of thermal challenges to bumblebee workers that would typically only be exposed to summer conditions. here we assess the ability of workers to survive acute and chronic cold stress (via lower lethal temperatures and lower lethal times at 0°c), the capacity for rapid cold hardening (rch) and the ...201324224036
dufour's gland secretion, sterility and foraging behavior: correlated behavior traits in bumblebee workers.bombus terrestris colonies go through two major phases: the "pre-competition phase" in which the queen is the sole reproducer and aggression is rare, and the "competition phase" in which workers aggressively compete over reproduction. conflicts over reproduction are partially regulated by a group of octyl esters that are produced in dufour's gland of reproductively subordinate workers and protect them from being aggressed. however, workers possess octyl esters even before overt aggression occurs ...201324100232
drifting behaviour as an alternative reproductive strategy for social insect workers.restricted reproduction is traditionally posited as the defining feature of eusocial insect workers. the discovery of worker reproduction in foreign colonies challenges this view and suggests that workers' potential to pursue selfish interests may be higher than previously believed. however, whether such reproductive behaviour truly relies on a reproductive decision is still unknown. workers' reproductive decisions thus need to be investigated to assess the extent of workers' reproductive option ...201324068358
molecular cloning and antifibrinolytic activity of a serine protease inhibitor from bumblebee (bombus terrestris) venom.bumblebee (bombus spp.) venom contains a variety of components, including bombolitin, phospholipase a(2) (pla(2)), serine proteases, and serine protease inhibitors. in this study, we identified a bumblebee (bombus terrestris) venom serine protease inhibitor (bt-kti) that acts as a plasmin inhibitor. bt-kti consists of a 58-amino acid mature peptide that displays features consistent with snake venom kunitz-type inhibitors, including six conserved cysteine residues and a p1 site. recombinant bt-kt ...201323164714
fluctuations in oxygen influence facultative endothermy in bumblebees.bumblebees are facultative endotherms, having the ability to elevate thorax temperature above ambient temperature by elevating metabolism. here, we investigated the influence of hypoxia on metabolic demands and thermoregulatory capabilities of the bumblebee bombus terrestris. we measured thorax temperature, rates of oxygen consumption and carbon dioxide production, and abdominal pumping rates of bees randomly exposed to oxygen levels of 20, 15, 10 and 5 kpa at 26°c. under normoxia, bumblebees ma ...201425355849
visual motion-sensitive neurons in the bumblebee brain convey information about landmarks during a navigational task.bees use visual memories to find the spatial location of previously learnt food sites. characteristic learning flights help acquiring these memories at newly discovered foraging locations where landmarks-salient objects in the vicinity of the goal location-can play an important role in guiding the animal's homing behavior. although behavioral experiments have shown that bees can use a variety of visual cues to distinguish objects as landmarks, the question of how landmark features are encoded by ...201425309374
bumblebee size polymorphism and worker response to queen pheromone.queen pheromones are chemical signals produced by reproductive individuals in social insect colonies. in many species they are key to the maintenance of reproductive division of labor, with workers beginning to reproduce individually once the queen pheromone disappears. recently, a queen pheromone that negatively affects worker fecundity was discovered in the bumblebee bombus terrestris, presenting an exciting opportunity for comparisons with analogous queen pheromones in independently-evolved e ...201425289189
control of self-motion in dynamic fluids: fish do it differently from bees.to detect and avoid collisions, animals need to perceive and control the distance and the speed with which they are moving relative to obstacles. this is especially challenging for swimming and flying animals that must control movement in a dynamic fluid without reference from physical contact to the ground. flying animals primarily rely on optic flow to control flight speed and distance to obstacles. here, we investigate whether swimming animals use similar strategies for self-motion control to ...201424872463
bumblebees (bombus terrestris) use social information as an indicator of safety in dangerous environments.avoiding predation is one of the most important challenges that an animal faces. several anti-predation behaviours can be employed, yet simply using the presence of conspecifics can be a good signal of safety in an environment with potential predation hazards. here, we show, for the first time, that past experience of predation causes bumblebees (bombus terrestris) to aggregate with conspecifics, facilitating the identification of safe foraging patches. bees were trained to differentiate between ...201424789891
going native? flower use by bumblebees in english urban gardens.although urban gardens provide opportunities for pollinators in an otherwise inhospitable environment, most garden plants are not native to the recipient biogeographical region and their value to local pollinators is disputed. this study tested the hypothesis that bumblebees foraging in english urban gardens preferentially visited sympatric palaearctic-range plants over species originating outside their native range.201424647914
divergent rules for pollen and nectar foraging bumblebees--a laboratory study with artificial flowers offering diluted nectar substitute and pollen surrogate.almost all bees collect nectar and pollen from flowers. female bees collect pollen to provision their nest cells, whereas they use nectar for individual energy supply and nest cell provisioning. bees fine-tune nectar foraging to the amount and to the concentration of nectar, but the individual bees' response to variability of amount and concentration of pollen reward has not yet been studied thoroughly in laboratory settings. we developed an experimental set-up in which bumblebees simultaneously ...201424637406
can bees see at a glance?primates can analyse visual scenes extremely rapidly, making accurate decisions for presentation times of only 20 ms. we asked whether bumblebees, despite having potentially more limited processing power, could similarly detect and discriminate visual patterns presented for durations of 100 ms or less. bumblebees detected stimuli and discriminated between differently oriented and coloured stimuli when presented as briefly as 25 ms but failed to identify ecologically relevant shapes (predatory sp ...201424625647
commercial bumblebee hives to assess an anthropogenic environment for pollinator support: a case study in the region of ghent (belgium).anthropogenic changes of the environment influence the distribution and abundance of pollinators such as bumblebees and have been proposed as one of the main causes in their worldwide decline. in order to evaluate the impact of expanding anthropogenic landscapes on supporting pollinator potential, reliable tools are needed. bombus terrestris is one of the most abundant bumblebee species in europe, and these bumblebees are known as generalist pollinators of not only wild flowers in nature but als ...201424297306
evolution of gonadotropin-inhibitory hormone receptor and its ligand.gonadotropin-inhibitory hormone (gnih) is a neuropeptide inhibitor of gonadotropin secretion, which was first identified in the japanese quail hypothalamus. gnih peptides share a c-terminal lpxrfamide (x=l or q) motif in most vertebrates. the receptor for gnih (gnihr) is the seven-transmembrane g protein-coupled receptor 147 (gpr147) that inhibits camp production. gpr147 is also named neuropeptide ff (npff) receptor 1 (npffr1), because it also binds npff that has a c-terminal pqrfamide motif. to ...201425220854
analysis of reference gene stability after israeli acute paralysis virus infection in bumblebees bombus terrestris.to date, there are no validated internal reference genes for the normalization of rt-qpcr data from virus infection experiments with pollinating insects. in this study we evaluated the stability of five candidate internal reference genes: elongation factor-1-alpha (elf1α), peptidylprolyl isomerase a (ppia), 60s ribosomal protein l23 (rpl23), tata-binding protein (tbp) and polyubiquitin (ubi), in relation to israeli acute paralysis virus (iapv) infection of bombus terrestris. we investigated the ...201424184950
bumblebees are not deterred by ecologically relevant concentrations of nectar toxins.bees visit flowers to collect nectar and pollen that contain nutrients and simultaneously facilitate plant sexual reproduction. paradoxically, nectar produced to attract pollinators often contains deterrent or toxic plant compounds associated with herbivore defence. the functional significance of these nectar toxins is not fully understood, but they may have a negative impact on pollinator behaviour and health, and, ultimately, plant pollination. this study investigates whether a generalist bumb ...201424526720
differential gene expression and alternative splicing in insect immune specificity.ecological studies routinely show genotype-genotype interactions between insects and their parasites. the mechanisms behind these interactions are not clearly understood. using the bumblebee bombus terrestris/trypanosome crithidia bombi model system (two bumblebee colonies by two crithidia strains), we have carried out a transcriptome-wide analysis of gene expression and alternative splicing in bees during c. bombi infection. we have performed four analyses, 1) comparing gene expression in infec ...201425431190
protein-poor diet reduces host-specific immune gene expression in bombus terrestris.parasites infect hosts non-randomly as genotypes of hosts vary in susceptibility to the same genotypes of parasites, but this specificity may be modulated by environmental factors such as nutrition. nutrition plays an important role for any physiological investment. as immune responses are costly, resource limitation should negatively affect immunity through trade-offs with other physiological requirements. consequently, nutritional limitation should diminish immune capacity in general, but does ...201424850921
gene expression differences underlying genotype-by-genotype specificity in a host-parasite system.in many systems, host-parasite evolutionary dynamics have led to the emergence and maintenance of diverse parasite and host genotypes within the same population. genotypes vary in key attributes: parasite genotypes vary in ability to infect, host genotypes vary in susceptibility, and infection outcome is frequently the result of both parties' genotypic identities. these host-parasite genotype-by-genotype (gh × gp) interactions influence evolutionary and ecological dynamics in important ways. int ...201424550506
few colonies of the host bombus terrestris disproportionately affect the genetic diversity of its parasite, crithidia bombi.sex and recombination have long been considered as necessary means for hosts to keep up with and resist to their faster reproducing parasites. on the other hand, comparatively little attention has been paid to potential benefits of recombination for the parasites. using as model organisms the bumblebee bombus terrestris and its genetically highly variable trypanosomatid parasite crithidia bombi we analysed the infection dynamics as well as the relative frequency of parasite recombinants over tim ...201424263111
the invasion of southern south america by imported bumblebees and associated parasites.the palaearctic bombus ruderatus (in 1982/1983) and bombus terrestris (1998) have both been introduced into south america (chile) for pollination purposes. we here report on the results of sampling campaigns in 2004, and 2010-2012 showing that both species have established and massively expanded their range. bombus terrestris, in particular, has spread by some 200 km year(-1) and had reached the atlantic coast in argentina by the end of 2011. both species, and especially b. terrestris, are infec ...201424256429
effect of oral infection with kashmir bee virus and israeli acute paralysis virus on bumblebee (bombus terrestris) reproductive success.israeli acute paralysis virus (iapv) together with acute bee paralysis virus (abpv) and kashmir bee virus (kbv) constitute a complex of closely related dicistroviruses. they are infamous for their high mortality after injection in honeybees. these viruses have also been reported in non-apis hymenopteran pollinators such as bumblebees, which got infected with iapv when placed in the same greenhouse with iapv infected honeybee hives. here we orally infected bombus terrestris workers with different ...201425004171
clearance of ingested neonicotinoid pesticide (imidacloprid) in honey bees (apis mellifera) and bumblebees (bombus terrestris).bees in agricultural landscapes are exposed to dietary pesticides such as imidacloprid when they feed from treated mass-flowering crops. concern about the consequent impact on bees makes it important to understand their resilience. in the laboratory, the authors therefore fed adult worker bees on dosed syrup (125 μg l(-1) of imidacloprid, or 98 μg kg(-1)) either continuously or as a pulsed exposure and measured their behaviour (feeding and locomotory activity) and whole-body residues.201423633150
effects of the neonicotinoid pesticide thiamethoxam at field-realistic levels on microcolonies of bombus terrestris worker bumble bees.neonicotinoid pesticides are currently implicated in the decline of wild bee populations. bumble bees, bombus spp., are important wild pollinators that are detrimentally affected by ingestion of neonicotinoid residues. to date, imidacloprid has been the major focus of study into the effects of neonicotinoids on bumble bee health, but wild populations are increasingly exposed to alternative neonicotinoids such as thiamethoxam. to investigate whether environmentally realistic levels of thiamethoxa ...201424238719
flies as pollinators of melittophilous salvia species (lamiaceae).•201425480711
the effect of caste and reproductive state on the chemistry of the cephalic labial glands secretion of bombus terrestris.the cephalic labial glands are well developed in many bee species. in bumble bee males, they cover most of the head volume, and their secretion is used in marking reproductive territories and attracting virgin queens. in females, however, they are poorly studied. here, we present chemical analyses of their secretion in queens and workers of bombus terrestris under various social conditions. the secretion revealed a context-dependent composition with sterile females possessing large amounts of fa ...201425119875
precocene-i inhibits juvenile hormone biosynthesis, ovarian activation, aggression and alters sterility signal production in bumble bee (bombus terrestris) workers.juvenile hormone (jh) is an important regulator of development and physiology in insects. while in many insect species, including bumble bees, jh functions as gonadotropin in adults, in some highly eusocial insects its role has shifted to regulate social behavior including division of labor, dominance and aggression. studying jh functions across social insect species is important for understanding the evolution of sociality; however, these studies have been limited because of the inability to re ...201425013106
gonadotropic and physiological functions of juvenile hormone in bumblebee (bombus terrestris) workers.the evolution of advanced sociality in bees is associated with apparent modifications in juvenile hormone (jh) signaling. by contrast to most insects in which jh is a gonadotropin regulating female fertility, in the highly eusocial honey bee (apis mellifera) jh has lost its gonadotrophic function in adult females, and instead regulates age-related division of labor among worker bees. in order to shed light on the evolution of jh signaling in bees we performed allatectomy and replacement therapie ...201424959888
herbivore defence compounds occur in pollen and reduce bumblebee colony fitness.herbivory defence chemicals in plants can affect higher trophic levels such as predators and parasitoids, but the impact on pollinators has been overlooked. we show that defensive plant chemicals can damage pollinator fitness when expressed in pollen. crop lupins (lupinus species from europe and south america) accumulate toxic quinolizidine alkaloids in vegetative tissues, conferring resistance to herbivorous pests such as aphids. we identified the alkaloid lupanine and its derivatives in lupin ...201424952086
bumblebees learn polarization patterns.foraging insect pollinators such as bees must find and identify flowers in a complex visual environment. bees use skylight polarization patterns for navigation, a capacity mediated by the polarization-sensitive dorsal rim area (dra) of their eye. while other insects use polarization sensitivity to identify appropriate habitats, oviposition sites, and food sources, to date no nonnavigational functions of polarization vision have been identified in bees. here we investigated the ability of bumbleb ...201424909321
foraging errors play a role in resource exploration by bumble bees (bombus terrrestris).if the cognitive performance of animals reflects their particular ecological requirements, how can we explain appreciable variation in learning ability amongst closely related individuals (e.g. foraging workers within a bumble bee colony)? one possibility is that apparent 'errors' in a learning task actually represent an alternative foraging strategy. in this study we investigate the potential relationship between foraging 'errors' and foraging success among bumble bee (bombus terrestris) worker ...201424838937
lactobacillus bombi sp. nov., from the digestive tract of laboratory-reared bumblebee queens (bombus terrestris).three bacterial strains belonging to the genus lactobacillus were isolated from the digestive tracts of laboratory-reared bumblebee queens (bombus terrestris) using mrs agar under anaerobic conditions. the isolates were identified according to 16s rrna gene sequence analysis as undescribed members of the genus lactobacillus, with the highest 16s rrna gene sequence similarity (96.9 %) to the uncharacterized bacterial strain lactobacillus sp. mboho2r2 isolated from the stomach of a european honeyb ...201424824637
royal jelly-like protein localization reveals differences in hypopharyngeal glands buildup and conserved expression pattern in brains of bumblebees and honeybees.royal jelly proteins (mrjps) of the honeybee bear several open questions. one of them is their expression in tissues other than the hypopharyngeal glands (hgs), the site of royal jelly production. the sole mrjp-like gene of the bumblebee, bombus terrestris (btrjpl), represents a pre-diversification stage of the mrjp gene evolution in bees. here we investigate the expression of btrjpl in the hgs and the brain of bumblebees. comparison of the hgs of bumblebees and honeybees revealed striking diffe ...201424682007
exploring the role of juvenile hormone and vitellogenin in reproduction and social behavior in bumble bees.the genetic and physiological pathways regulating behavior in solitary species are hypothesized to have been co-opted to regulate social behavior in social species. one classic example is the interaction between vitellogenin (an egg-yolk and storage protein) and juvenile hormone, which are positively correlated in most insect species but have modified interactions in highly eusocial insects. in some of these species (including some termites, ants, and the honey bee), juvenile hormone and vitello ...201424618396
cross-linking in the silks of bees, ants and hornets.silk production is integral to the construction of nests or cocoons for many aculeata, stinging hymenopterans such as ants, bees and wasps. here we report the sequences of new aculeate silk proteins and compare cross-linking among nine native silks from three bee species (apis mellifera, bombus terrestris and megachile rotundata), three ant species (myrmecia forficata, oecophylla smaragdina and harpegnathos saltator) and three hornets (vespa analis, vespa simillima and vespa mandarinia). the wel ...201424607851
changes in learning and foraging behaviour within developing bumble bee (bombus terrestris) colonies.organisation in eusocial insect colonies emerges from the decisions and actions of its individual members. in turn, these decisions and actions are influenced by the individual's behaviour (or temperament). although there is variation in the behaviour of individuals within a colony, we know surprisingly little about how (or indeed if) the types of behaviour present in a colony change over time. here, for the first time, we assessed potential changes in the behavioural type of foragers during col ...201424599144
molecular heterochrony and the evolution of sociality in bumblebees (bombus terrestris).sibling care is a hallmark of social insects, but its evolution remains challenging to explain at the molecular level. the hypothesis that sibling care evolved from ancestral maternal care in primitively eusocial insects has been elaborated to involve heterochronic changes in gene expression. this elaboration leads to the prediction that workers in these species will show patterns of gene expression more similar to foundress queens, who express maternal care behaviour, than to established queens ...201424552837
methylation and worker reproduction in the bumble-bee (bombus terrestris).insects are at the dawn of an epigenetics era. numerous social insect species have been found to possess a functioning methylation system, previously not thought to exist in insects. methylation, an epigenetic tag, may be vital for the sociality and division of labour for which social insects are renowned. in the bumble-bee bombus terrestris, we found methylation differences between the genomes of queenless reproductive workers and queenless non-reproductive workers. in a follow up experiment, q ...201424523266
observational conditioning in flower choice copying by bumblebees (bombus terrestris): influence of observer distance and demonstrator movement.bumblebees use information provided inadvertently by conspecifics when deciding between different flower foraging options. such social learning might be explained by relatively simple associative learning mechanism: the bee may learn to associate conspecifics with nectar or pollen reward through previous experience of foraging jointly. however, in some studies, observers were guided by choices of 'demonstrators' viewed through a screen, so no reward was given to the observers at the time of seei ...201424516654
cloning and expression analysis of a transformer gene in daphnia pulex during different reproduction stages.the full-length cdna of a transformer gene (dptra) was cloned from the cladoceran daphnia pulex using race. dptra expression was assessed by qpcr and whole-mount in situ hybridization in different reproductive stages. the dptra cdna, 1652bp in length, has a 1158-bp open reading frame that encodes a 385 amino acid polypeptide containing one sex determination protein n terminal (sdp_n) superfamily, eight putative phosphorylation sites, and an arginine-serine (rs)-rich domain at the n-terminus. dpt ...201424725535
a new threat to bees? entomopathogenic nematodes used in biological pest control cause rapid mortality in bombus terrestris.there is currently a great deal of concern about population declines in pollinating insects. many potential threats have been identified which may adversely affect the behaviour and health of both honey bees and bumble bees: these include pesticide exposure, and parasites and pathogens. whether biological pest control agents adversely affect bees has been much less well studied: it is generally assumed that biological agents are safer for wildlife than chemical pesticides. the aim of this study ...201526618084
flight control and landing precision in the nocturnal bee megalopta is robust to large changes in light intensity.like their diurnal relatives, megalopta genalis use visual information to control flight. unlike their diurnal relatives, however, they do this at extremely low light intensities. although megalopta has developed optical specializations to increase visual sensitivity, theoretical studies suggest that this enhanced sensitivity does not enable them to capture enough light to use visual information to reliably control flight in the rainforest at night. it has been proposed that megalopta gain extra ...201526578977
conservation and modification of genetic and physiological toolkits underpinning diapause in bumble bee queens.diapause is the key adaptation allowing insects to survive unfavourable conditions and inhabit an array of environments. physiological changes during diapause are largely conserved across species and are hypothesized to be regulated by a conserved suite of genes (a 'toolkit'). furthermore, it is hypothesized that in social insects, this toolkit was co-opted to mediate caste differentiation between long-lived, reproductive, diapause-capable queens and short-lived, sterile workers. using bombus te ...201526453894
dumb and lazy? a comparison of color learning and memory retrieval in drones and workers of the buff-tailed bumblebee, bombus terrestris, by means of per conditioning.more than 100 years ago, karl von frisch showed that honeybee workers learn and discriminate colors. since then, many studies confirmed the color learning capabilities of females from various hymenopteran species. yet, little is known about visual learning and memory in males despite the fact that in most bee species males must take care of their own needs and must find rewarding flowers to obtain food. here we used the proboscis extension response (per) paradigm to study the color learning capa ...201526230643
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