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International audience; Recent improvements in taxonomy consider multiple operational criteria. Integrative taxonomy provides a methodological framework merging these multisource approaches. Bumblebees are considered as a uniform group where their taxonomy remains one of the most difficult. Here, we investigate the taxonomic statuses inside a monophyletic group including six taxa (B. inexspectatus, B. mlokosievitzii, B. ruderarius, B. sylvarum, B. velox and B. veteranus)in the most diverse subgenus of bumblebees: Thoracobombus. We used an integrative approach based on mitochondrial and nuclear genetic markers and eco-chemical traits commonly used in bumblebee taxonomy. For all species, our study shows a clear differentiation in DNA and eco-chemical traits. However, we conserve the subspecies status of B. ruderarius simulatilis and B. sylvarum daghestanicus from the east of Turkey and Iran according to their degree of genetic and eco-chemical differentiation

Males of many bumblebee species exhibit a conspicuous pre-mating behavior with two distinct behavioral components: scent marking and patrol flying. The marking pheromone is produced by the cephalic part of the labial gland (CLG). As far as is known, the CLG secretion is species specific, and it usually consists of two types of compounds: (i) straight-chain aliphatic alcohols, aldehydes or esters, and (ii) acyclic mono-, sesqui- and diterpenes (alcohols or acetates). Here, we summarize data from the literature reporting chemical composition of the CLG secretions of more than 80 bumblebee species. Similarities and differences within and between subgenera are discussed in the context of biosynthetic pathways and evolution.

Cold-adapted species are expected to have reached their largest distribution range during a part of the Ice Ages whereas postglacial warming has led to their range contracting toward high-latitude ...

The bumblebee wax moth, Aphomia sociella, is a parasite of bumblebees. In this species, males produce sexual pheromone to attract females, while females produce an aphrodisiac pheromone that initiates male courtship. Both pheromones contain 6,10,14-trimethylpentadecan-2-one (TMPD-one) and the corresponding alcohol, 6,10,14-trimethylpentadecan-2-ol (TMPD-ol) in sex specific quantities. Male sex pheromone consists of 7 components with TMPD-one as a minor one and traces of TMPD-ol. In female aphrodisiac pheromone, TMPD-ol is the major component, while TMPD-one is present in traces. Here we report on the absolute configuration of TMPD-one in male sex pheromone and TMPD-ol in female aphrodisiac pheromone of A. sociella. The configuration was determined from GC/MS of prepared (S)-acetoxypropionyl esters of TMPD-ol. TMPD-one was first reduced to the alcohol that was then derivatized with (S)-acetoxypropionyl chloride. The GC/MS data of obtained diastereoisomers were compared with synthetic standards. The absolute configuration of TMPD-one in the male pheromone was (6R,10R). The configuration of TMPD-ol in the female pheromone was (2R,6R,10R). Electrophysiological experiments showed that TMPD-one and TMPD-ol are perceived by both sexes. The synthetic standards of naturally produced stereoisomers elicited higher responses than mixtures of all stereoisomers. We are grateful to J. Titzenthalerová for her skillful assistance in electrophysiological experiments and to R. Hanus for his help with statistical evaluations of the EAG recordings. This work was financially supported by the Ministry of Education of the Czech Republic (grant No. LD15102). The research was done within the frames of the COST Action Super-B (FA1307). EW and EH are thankful for the funding from ERUF (European regional developmental fund), the region of Jämtland/Härjedalen and the region of Västernorrland.

A fast, inexpensive, and ecological method based on liquid-liquid extraction principle has been developed for preparation of extract with high content of Nigella sativa (N. sativa) quinones. The gas chromatography-mass spectrometry (GC-MS) analysis showed that oil extraction using 70% ethanol for 6 h yielded extract containing 50% of thymoquinone (TQ) and 13% of thymohydroquinone (THQ).

Bumblebees have been the focus of much research, but the taxonomy of many species groups is still unclear, especially for circumpolar species. Delimiting species based on multisource datasets provides a solution to overcome current systematic issues of closely related populations. Here, we use an integrative taxonomic approach based on new genetic and eco-chemical datasets to resolve the taxonomic status of Bombus lapponicus and Bombus sylvicola. Our results support the conspecific status of B. lapponicus and B. sylvicola and that the low gradual divergence around the Arctic Circle between Fennoscandia and Alaska does not imply speciation in this species complex. Therefore, based on our molecular and morphological analyses, we propose to assign them subspecific status: Bombus lapponicus lapponicus from Fennoscandia and West Siberia and Bombus lapponicus sylvicola comb. nov. from Alaska and Yukon. In addition, our analyses reveal a cryptic species in the B. lapponicus complex from Alaska, which we describe here as new: Bombus (Pyrobombus) interacti sp. nov.

Social parasitic Hymenopterans have evolved morphological, chemical, and behavioral adaptations to overcome the sophisticated recognition and defense systems of their social host to invade host nests and exploit their worker force. In bumblebees, social parasitism appeared in at least 3 subgenera independently: in the subgenus Psithyrus consisting entirely of parasitic species, in the subgenus Alpinobombus with Bombus hyperboreus, and in the subgenus Thoracobombus with B. inexspectatus. Cuckoo bumblebee males utilize species-specific cephalic labial gland secretions for mating purposes that can impact their inquiline strategy. We performed cephalic labial gland secretions in B. hyperboreus, B. inexspectatus and their hosts. Males of both parasitic species exhibited high species specific levels of cephalic gland secretions, including different main compounds. Our results showed no chemical mimicry in the cephalic gland secretions between inquilines and their host and we did not identify the repellent compounds already known in other cuckoo bumblebees.

The current bumblebee decline leads to inbreeding in populations that fosters a loss of allelic diversity and diploid male production. As diploid males are viable and their offspring are sterile, bumblebee populations can quickly fall in a vortex of extinction. In this article, we investigate for the first time a potential premating mechanism through a major chemical reproductive trait (male cephalic labial gland secretions) that could prevent monandrous virgin queens from mating with diploid males. We focus our study on the cephalic labial gland secretions of diploid and haploid males of Bombus terrestris (L.). Contrary to initial expectations, our results do not show any significant differentiation of cephalic labial gland secretions between diploid and haploid specimens. Queens seem therefore to be unable to avoid mating with diploid males based on their compositions of cephalic labial gland secretions. This suggests that the vortex of extinction of diploid males could not be stopped through premating avoidance based on the cephalic labial gland secretions but other mechanisms could avoid mating between diploid males and queens.

International audience; AbstractSpecies taxonomy of bumblebees (Bombus Latreille, 1802) is well known to be problematic due to a potentially high intra-specific variability of morphological traits while different species can converge locally to the same color pattern (cryptic species). Assessing species delimitation remains challenging because it requires to arbitrarily select variable traits whose accuracy continues to be debated. Integrative taxonomic approach seems to be very useful for this group as different independent traits are assessed to propose a rational taxonomic hypothesis. Among operational criteria to assess specific status, the reproductive traits involved in the pre-mating recognition (i.e., the male cephalic labial gland secretions, CLGS) have been premium information. Since these secretions are supposed to be species-specific, these chemical traits can bring essential information where species delimitation is debated. Here, we describe and compare the CLGS of 161 male specimens of nine Alpinobombus taxa: alpinus, balteatus, helleri, hyperboreus, kirbiellus, natvigi, neoboreus, polaris, and pyrrhopygus. We aim also to test the congruence between this new information (reproductive traits) and published genetic dataset. Our results emphasized six distinct groups with diagnostic major compounds: (a) alpinus + helleri with hexadec-9-en-1-ol; (b) polaris + pyrrhopygus with two major compounds hexadec-9-en-1-ol and hexadec-9-enal; (c) balteatus with tetradecyl acetate; (d) kirbiellus with geranyl geranyl acetate; (e) hyperboreus + natvigi with octadec-11-en-1-ol; (f) neoboreus with octadec-9-en-1-ol. Based on this new information, we can confirm the species status of B. alpinus, B. balteatus, B. hyperboreus, B. kirbiellus, B. neoboreus, and B. polaris. We also confirm the synonymy of helleri (Alps) with alpinus (Sweden). However, the specific status of natvigi (Alaska) and pyrrhopygus (Sweden) is questionable and these taxa do not have specific CLGS composition.

Fatty acyl reductases (FARs) are involved in the biosynthesis of fatty alcohols that serve a range of biological roles. Insects typically harbor numerous FAR gene family members. While some FARs are involved in pheromone biosynthesis, the biological significance of the large number of FARs in insect genomes remains unclear. Using bumble bee (Bombini) FAR expression analysis and functional characterization, hymenopteran FAR gene tree reconstruction, and inspection of transposable elements (TEs) in the genomic environment of FARs, we uncovered a massive expansion of the FAR gene family in Hymenoptera, presumably facilitated by TEs. The expansion occurred in the common ancestor of bumble bees and stingless bees (Meliponini). We found that bumble bee FARs from the expanded FAR-A ortholog group contribute to the species-specific pheromone composition. Our results indicate that expansion and functional diversification of the FAR gene family played a key role in the evolution of pheromone communication in Hymenoptera., eLife digest Many insects release chemical signals, known as sex pheromones, to attract mates over long distances. The pheromones of male bumble bees, for example, contain chemicals called fatty alcohols. Each species of bumble bee releases a different blend of these chemicals, and even species that are closely related may produce very different ‘cocktails’ of pheromones. The enzymes that make fatty alcohols are called fatty acyl reductases (or FARs for short). Any change to a gene that encodes one of these enzymes could change the final mix of pheromones produced. This in turn could have far-reaching effects for the insect, and in particular its mating success. Over time, these changes could even result in new species. Yet no one has previously looked into how the genes for FAR enzymes have evolved in bumble bees, or how these genes might have shaped the evolution of this important group of insects. Tupec, Buček et al. set out to learn what genetic changes led the males of three common species of bumble bees to make dramatically different mixes of pheromones. Comparing the genetic information of bumble bees with that of other insects showed that the bumble bees and their close relatives, stingless bees, often had extra copies of genes for certain FAR enzymes. Inserting some of these genes into yeast cells caused the yeast to make the correct blend of bumble bee pheromones, confirming that these genes did indeed produce the mixture of chemicals in these signals. Further, detailed analysis of the bumble bees’ genetic information revealed many genetic sequences, called transposable elements, close to the genes for the FAR enzymes. Transposable elements make the genetic material less stable; they can be ‘cut’ or ‘copied and pasted’ in multiple locations and often cause other genes to be duplicated or lost. Tupec et al. concluded that these transposable elements led to a dramatic increase in the number of genes for FAR enzymes in a common ancestor of bumble bees and stingless bees, ultimately allowing a new pheromone ‘language’ to evolve in these insects. These results add to our understanding of the chemical and genetic events that influence what chemicals insects use to communicate with each other. Tupec, Buček et al. also hope that a better knowledge of the enzymes that insects use to make pheromones could have wide applications. Other insects – including pest moths – use a similar mixture of fatty alcohols as pheromones. Artificially produced enzymes, such as FAR enzymes, could thus be used to mass-produce pheromones that may control insect pests.

Lepidoptera evolved tympanic ears in response to echolocating bats. Comparative studies have shown that moth ears evolved many times independently from chordotonal organs. With only 1 to 4 receptor cells, they are one of the simplest hearing organs. The small number of receptors does not imply simplicity, neither in behavior nor in the neural circuit. Behaviorally, the response to ultrasound is far from being a simple reflex. Moths’ escape behavior is modulated by a variety of cues, especially pheromones, which can alter the auditory response. Neurally the receptor cell(s) diverges onto many interneurons, enabling parallel processing and feature extraction. Ascending interneurons and sound-sensitive brain neurons innervate a neuropil in the ventrolateral protocerebrum. Further, recent electrophysiological data provides the first glimpses into how the acoustic response is modulated as well as how ultrasound influences the other senses. So far, the auditory pathway has been studied in noctuids. The findings agree well with common computational principles found in other insects. However, moth ears also show unique mechanical and neural adaptation. Here, we first describe the variety of moths’ auditory behavior, especially the co-option of ultrasonic signals for intraspecific communication. Second, we describe the current knowledge of the neural pathway gained from noctuid moths. Finally, we argue that Galleriinae which show negative and positive phonotaxis, are an interesting model species for future electrophysiological studies of the auditory pathway and multimodal sensory integration, and so are ideally suited for the study of the evolution of behavioral mechanisms given a few receptors.

Sex-specific chemical secretions have been widely used as diagnostic characters in chemotaxonomy. The taxonomically confused group of bumblebees has reaped the benefit of this approach through the analyses of cephalic labial gland secretions (CLGS). Most of currently available CLGS descriptions concern species from the West-Palearctic region but few from the New World. Here, the CLGS of four East-Palearctic species Bombus deuteronymus, B. filchnerae, B. humilis, and B. exil (subgenus Thoracobombus) are analysed. Our results show high levels of variability in the major compounds in B. exil. In contrast, we describe a low differentiation in CLGS compounds between B. filchnerae and its phylogenetically closely related taxon B. muscorum. Moreover, the chemical profiles of B. filchnerae and B. muscorum are characterized by low concentrations of the C16 component, which is found in higher concentrations in the other Thoracobombus species. This raises the possibility that courtship behavior as well as environmental constraints could affect the role of the bumblebee males' CLGS.

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 honeybee (Apis mellifera). Lactobacillus tucceti was found to be the closest related species with a validly published name, with 92.9 % 16S rRNA gene sequence similarity to the type strain. However, phylogenetic analyses based on different markers revealed that this species is phylogenetically very distant from the novel strains. The DNA G+C content of the proposed type strain BTLCH M1/2T is 37.8 mol%. The fatty acids C19 : 1ω6c and/or C19 : 0 cyclo ω10c/19ω6, C18 : 1ω9c and C16 : 0 were predominant in all strains. Diphosphatidylglycerol, phosphatidylglycerol, a phospholipid, seven glycolipids and two phosphoglycolipids were detected in the novel strains. Growth was observed at 47 °C. The peptidoglycan type A4α l-Lys–d-Asp was determined for strain BTLCH M1/2T. Genotypic characteristics and phylogenetic analyses based on the phylogenetic markers hsp60, pheS, rpoA and tuf as well as phenotypic characteristics and the results of chemotaxonomic analyses confirmed that the new isolates belong to a novel species of the genus Lactobacillus , for which the name Lactobacillus bombi sp. nov. is proposed. The type strain is BTLCH M1/2T ( = DSM 26517T = CCM 8440T).

Triacylglycerols (TGs) stored in the fat bodies of bumblebee males have a species-specific composition. The striking structural similarities between TG fatty acids (FAs) and components of the male marking pheromone in certain species led to the hypothesis that FAs may serve as precursors in pheromone biosynthesis. Here, we analysed TGs from B. ruderatus, B. bohemicus, and B. campestris. Nonadec-9-ene and icos-15-en-1-ol are the main components of B. ruderatus labial gland secretion, forming up to 92% of the gland extract. The corresponding icos-11-enic and icos-15-enic acids were found in TGs at levels higher than usual for bumblebee species. We found similar relationships in B. campestris and B. bohemicus. These results suggest that FAs might be precursors of aliphatic compounds in the male pheromones. Furthermore, we report for the first time the pheromone structure of B. ruderatus males.

Understanding the social evolution leading to insect eusociality requires, among other, a detailed insight into endocrine regulatory mechanisms that have been co-opted from solitary ancestors to play new roles in the complex life histories of eusocial species. Bumblebees represent well-suited models of a relatively primitive social organization standing on the mid-way to highly advanced eusociality and their queens undergo both, a solitary and a social phase, separated by winter diapause. In the present paper, we characterize the gene expression levels of major endocrine regulatory pathways across tissues, sexes, and life-stages of the buff-tailed bumblebee, Bombus terrestris, with special emphasis on critical stages of the queen’s transition from solitary to social life. We focused on fundamental genes of three pathways: (1) Forkhead box protein O and insulin/insulin-like signaling, (2) Juvenile hormone signaling, and (3) Adipokinetic hormone signaling. Virgin queens were distinguished by higher expression of forkhead box protein O and downregulated insulin-like peptides and juvenile hormone (JH) signaling, indicated by low expression of methyl farnesoate epoxidase (MFE) and transcription factor Kruppel homolog 1 (Kr-h1). Diapausing queens showed the expected downregulation of JH signaling in terms of low MFE and vitellogenin (Vg) expressions, but an unexpectedly high expression of Kr-h1. By contrast, reproducing queens revealed an upregulation of MFE and Vg together with insulin signaling. Surprisingly, the insulin growth factor 1 (IGF-1) turned out to be a queen-specific hormone. Workers exhibited an expression pattern of MFE and Vg similar to that of reproducing queens. Males were characterized by high Kr-h1 expression and low Vg level. The tissue comparison unveiled an unexpected resemblance between the fat body and hypopharyngeal glands across all investigated genes, sexes, and life stages.

International audience; The species international trade leads to multiple non-native invasions. Besides species invasions, commercial exchanges may also contribute to translocation between closely related taxa or allopatric populations. Consequently, preserving endemic taxa and specificity of local populations require to regulate commercial translocations of species or populations. To be efficient such regulation needs a resolved taxonomy and a thorough analysis of the population structure of native taxa/populations. To provide guidelines for an efficient regulation of the trade of Bombus terrestris within its natural range, we analyzed its taxonomy and its population structure using an integrative taxonomic approach. Our results show that B. terrestris translocations involve two species, three subspecies, and several populations with weak differentiation. These different levels of differentiation imply specific and appropriate regulations of translocations with different levels of prioritization. We ultimately assess the relevance of current policies and propose potentially efficient regulations for policy-makers. Such integrative taxonomic approach should be used in other traded polytypic species.

Biotransformation of (1S)-2-carene and (1S)-3-carene by Picea abies suspension culture led to the formation of oxygenated products. (1S)-2-Carene was transformed slowly and the final product was identified as (1S)-2-caren-4-one. On the other hand, the transformation of (1S)-3-carene was rapid and finally led to the formation of (1S)-3-caren-5-one and (1S)-2-caren-4-one as equally abundant major products. The time-course of the reaction indicates that some products abundant at the beginning of the reaction (e.g. (1S, 3S, 4R)-3,4-epoxycarane and (1R)-p-mentha-1(7),2-dien-8-ol) were consumed by a subsequent transformations. Thus, a precise selection of the biotransformation time may be used for a production of specific compounds.

Amaryllidaceae are known as ornamental plants, furthermore some species of this family contain galanthamine, an acetylcholinesterase inhibitor approved for the treatment of Alzheimer's disease, and other alkaloids with interesting pharmacological activity. The chemical composition of alkaloids from Zephyranthes grandiflora Lindl. was analyzed by GC/MS. Seven known compounds, belonging to five structural types of Amaryllidaceae alkaloids, were identified. The alkaloid extract from the bulbs showed promising cholinesterase inhibitory activities against human blood acetylcholinesterase (HuAChE; IC50 39.2±3.0 µg/mL) and human plasma butyrylcholinesterase (HuBuChE; IC50 356±9.3 µg/mL).

In the present study, trail pheromone blends are identified for the first time in termites. In the phylogenetically complex Nasutitermitinae, trail-following pheromones are composed of dodecatrienol and neocembrene, the proportions of which vary according to species, although neocembrene is always more abundant than dodecatrienol (by 25–250-fold). Depending on species, termites were more sensitive to dodecatrienol or to neocembrene but the association of both components always elicited significantly higher trail following, with a clear synergistic effect in most of the studied species. A third component, trinervitatriene, was identified in the sternal gland secretion of several species, but its function remains unknown. The secretion of trail pheromone blends appears to be an important step in the evolution of chemical communication in termites. The pheromone optimizes foraging, and promotes their ecological success.

Although the frontal gland has long been known as a prominent defensive device for termite soldiers in many Rhinotermitidae and Termitidae, almost nothing is known about its function in imagoes. In the present study, we show that the frontal gland of imagoes in Prorhinotermes species is well developed at the time of the nuptial flight, and is filled with a complex mixture of sesquiterpene hydrocarbons and nitroalkenes. The sesquiterpene composition varies between Prorhinotermes simplex and Prorhinotermes canalifrons, between geographically distant colonies of P. simplex (Cuba versus Florida), and even between different flights of closely-related subcolonies. The ratio between (E)-1-nitropentadec-1-ene and sesquiterpenes is sex-specific. The volume of secretory cells decreases in functional kings and queens after colony foundation, and the subcellular organization changes into a form resembling unmodified epidermal cells. Dealate reproductives lose the ability for biosynthesis, and their frontal gland is devoid of volatile compounds found in swarming imagoes. The results obtained in the present study clearly show that the frontal gland is only temporarily active at the time of the dispersal flight. The most likely function of this gland is defence by the toxic nitroalkenes. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98, 384–392.

Nigella sativa L. seed essential oils obtained by hydrodistillation (HD), dry steam distillation (SD), steam distillation of crude oils obtained by solvent extraction (SE-SD), and supercritical fluid extraction (SFE-SD) were tested for their antibacterial activities, using the broth microdilution method and subsequently analyzed by gas chromatography and gas chromatography-mass spectrometry. The results showed that the essential oils tested differed markedly in their chemical compositions and antimicrobial activities. The oils obtained by HD and SD were dominated by p-cymene, whereas the major constituent identified in both volatile fractions obtained by SD of extracted oils was thymoquinone (ranging between 0.36 and 0.38 g/ml, whereas in oils obtained by HD and SD, it constituted only 0.03 and 0.05 g/ml, respectively). Both oils distilled directly from seeds showed lower antimicrobial activity (MICs > or = 256 and 32 microg/ml for HD and SD, respectively) than those obtained by SE-SD and SFE-SD (MICs > or = 4 microg/ml). All oil samples were significantly more active against gram-positive than against gram-negative bacteria. Thymoquinone exhibited potent growth-inhibiting activity against gram-positive bacteria, with MICs ranging from 8 to 64 microg/ml.

International audience; The evolution of signals and reproductive traits involved in the pre-mating recognition has been in focus of abundant research in several model species, such as bumblebees (genus Bombus). However, the most-studied bumblebee reproductive trait, the male cephalic labial gland secretions (CLGS), remains unknown among bumblebee species from South America. In this study, the CLGS of five South American bumblebees of the subgenera Thoracobombus (Bombus excellens and B. atratus) and Cullumanobombus (B. rubicundus, B. hortulanus, and B. melaleucus) were investigated, by comparing the chemical compositions of their secretions to those of closely related European species. The results showed an obvious interspecific differentiation in both subgenera. The interspecific differentiation among the species of the Thoracobombus subgenus involved different compounds present at high contents (main compounds), while those of the Cullumanobombus subgenus shared the same main components. This suggests that among the species of the Cullumanobombus subgenus, the differentiation in minor components could lead to species discrimination.

According to the species recognition concept of Paterson, the analyses of the secretions of the cephalic parts of the male labial glands confirm the conspecificity of Bombus (Thoracobombus) ruderarius ruderarius and B. (T.) r. montanus populations from the Pyrenees. These secretions were compared in B. ruderarius and B. sylvarum. We identified the same 7 major compounds as previously known for these species. We also identified 69 minor compounds. These minor compounds emphasise the close relationship between both species. Principal Component Analyses (PCA) were carried out on standardised peak areas of GC-MS chromatograms. The first PCA component is discriminant and shows no overlap between both species. Their secretions differ mostly by the relative concentration of their compounds rather than by their qualitative composition. On the contrary, PCA is unable to separate montanus from ruderarius. The larger variance in the secretions of B. ruderarius results from the very low concentration of the main compound (9-hexadecenol) in some specimens. Bombus sylvarum sylvarum / Bombus ruderarius ruderarius / Bombus ruderarius montanus / sexual pheromone / cephalic labial gland secretion / chemosystematics

When subjected to a Picea abies suspension cell culture, beta-pinene, either one of the pure enantiomers or the racemate, was transformed mainly to trans-pinocarveol along with the minor products myrtenol, alpha-terpineol, pinocarvone, myrtenal and cis-pinocarveol. The absolute configuration of the major products corresponded to that of the starting beta-pinene enantiomer. Some of the primary transformation products, i.e. (1S)-cis- and (1S)-trans-pinocarveol, (1R)-myrtenol and (4S)-alpha-terpineol, were also tested as substrates of the P. abies suspension culture. They reacted more slowly than beta-pinene but, except for (4S)-alpha-terpineol, they were all transformed. Thus, (1R)-myrtenol was converted into both (1R)-myrtenal and (1R)-myrtanol, whereas (1S)-trans-pinocarveol was converted into (1S)-pinocarvone. (4R)-Limonene was slowly transformed by the suspension culture into limonene-(1,2)-epoxide as the major product, with carveol, perillyl alcohol and 1,8-cineole as minor products. Autoxidation of terpenes in cell-free nutrient medium was investigated in detail. Alpha-pinene and beta-pinene were both autoxidized to a certain extent, while limonene remained unaffected. The rate of the autoxidation was more than one order of magnitude slower than that of the biotransformation. Moreover, different products were formed by autoxidation than by biotransformation.

International audience; AbstractMany species display local variations in pre-mating signals and in mating preferences. This may lead to discrimination against potential foreign mates that may ultimately lead to reproductive isolation. However, the extent to which population differentiation in mating cues affects the species recognition has received little empirical support. Here, we investigate the consequence of geographic differentiation in male reproductive traits on female preferences to these traits in Bombus terrestris. We characterise (1) the geographic differentiation in male cephalic labial gland secretions (CLGS), a key trait for mate attraction, and (2) the preference of virgin females to the CLGS of different subspecies. Our results show geographic CLGS differences parallel with divergences in female preferences for these secretions. This geographic CLGS differentiation in males, along with female preference for sympatric males, could lead to or reflect a pre-mating isolation among subspecies.

Insects’ fat bodies are responsible for nutrient storage and for a significant part of intermediary metabolism. Thus, it can be expected that the structure and content of the fat body will adaptively change, if an insect is going through different life stages. Bumblebee queens belong to such insects as they dramatically change their physiology several times over their lives in relation to their solitary overwintering, independent colony foundation stage, and during the colony life-cycle ending in the senescent stage. Here, we report on changes in the ultrastructure and lipid composition of the peripheral fat body of Bombus terrestris queens in relation to seasonal changes in the queens’ activity. Six life stages are defined and evaluated in particular: pharate, callow, before and after hibernation, egg-laying, and senescence. Transmission electron microscopy revealed that the fat body contained two main cell types–adipocytes and oenocytes. Only adipocytes reveal important changes related to the life phase, and mostly the ration between inclusion and cytoplasm volume varies among particular stages. Both electron microscopy and chemical analyses of lipids highlighted seasonal variability in the quantity of the stored lipids, which peaked prior to hibernation. Triacylglycerols appeared to be the main energy source during hibernation, while the amount of glycogen before and after hibernation remained unchanged. In addition, we observed that the representation of some fatty acids within the triacylglycerols change during the queen’s life. Last but not least, we show that fat body cell membranes do not undergo substantial changes concerning phospholipid composition in relation to overwintering. This finding supports the hypothesis that the cold-adaptation strategy of bumblebee queens is more likely to be based on polyol accumulation than on the restructuring of lipid membranes.

Labial gland secretions of 22 males of the bumblebee Bombus pomorum , collected in the Czech Republic, were analysed separately for each individual. The secretions contained 70 compounds among which saturated and unsaturated hydrocarbons strongly dominated. The proportion of hydrocarbons in the secretion was unusually high (85-100% ) compared to other bumblebee species studied so far (3-15%). Methyl and ethyl esters of fatty acids, known from many other bumblebee species, formed only minor components (less than 1 % in sum) of the secretions of several B. pomorum individuals. No terpenic compounds, typical for males’ marking secretion of many bumblebee species, were detected in B. pomorum . The absolute quantities of hydrocarbons present in the labial gland extracts were comparable with those usually present in other species. The composition of hydrocarbons found in the labial glands was different from the profile of the cuticular hydrocarbons. Despite our expectations in species exhibiting a regular patrolling and scent-marking behaviour, the labial gland extracts obtained from B. pom orum males were unusually low concentrated and their chemical composition was atypical with respect of the proportions of hydrocarbons when compared with other patrolling species. This is the first report on the analysis of the labial gland secretion of the B. pomorum males.

Commonly used dynamic sorption techniques for collecting biologically active volatile compounds have been compared. Solid phase microextraction (SPME) using two types of fibers (polydimethylsiloxane, PDMS, 100 μm, and carbowax/divinylbenzene, CW/DVB, 65 μm) was compared to purge and trap methods (Porapak Q, Tenax TA and charcoal) and a technique based on absorption in methanol in a cooling bath. Sampling was done in a stream of purified air (20 ml/min) in a closed and temperature-regulated (27 °C) glass tube, passing over a capillary tube containing a hexane solution of tridecane, heptadecane, 1-octen-3-ol, 1- hexadecanol, ethyl tetradecanoate, α-pinene, linalool, terpinen-4-ol, cis-verbenol, verbenone, β-caryophyllene, E,E-farnesol, and geranylgeraniol. With all of the methods, the sampling was performed for a period of 30 min before extraction and analysis was done on a GC-FID system. In general, SPME gave a higher response for all compounds except for a-pinene, which was only extracted by the CW/DVB fiber. Purge and trap methods and methanol absorption gave the same response for all substances extracted. None of the methods extracted hexadecanol and geranylgeraniol under the conditions used. However, the SPME equipped with the PDMS coating extracted heptadecane, E,E-farnesol and ethyl tetradecanoate. Our results show that SPME, when selecting the fibers to fit the polarity and volatility of the compounds, is an outstanding extraction method compared to purge and trap and methanol absorption, especially for a qualitative analysis. The best conditions for storing fibers exposed to compounds of high volatility were at low temperatures (6 °C) in sealed vials, while the worst way was to leave the exposed fiber unprotected at room temperature (22 °C). The dynamic sampling system was effectively tested on a fruiting body of a polypore fungus ( Ganoderma applanatum) emitting 1-octen-3-ol, and again SPME showed to be the most sensitive technique.

The biotransformation course of S-(−)-limonene by Solanum aviculare and Dioscorea deltoidea plant cells was studied using 5 different immobilization methods (entrapment into alginate, carrageenan and pectate gels, binding to polyphenyleneoxide and permeation into polyurethane foam). All techniques, with exception of permeation into pre-formed matrix, affected the product ratio. The main products were cis- and trans-carveol and carvone.

BACKGROUND: 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. RESULTS: We studied the temporal dynamics of lipolytic activity in crude extracts from the cephalic part of Bombus terrestris labial glands. Extracts from 3-day-old males displayed the highest lipolytic activity. The highest lipase gene expression level was observed in freshly emerged bumblebees, and both gene expression and lipase activity were lower in bumblebees older than 3 days. Lipase was purified from labial glands, further characterized and named as BT-1. The B. terrestris orthologue shares 88% sequence identity with B. impatiens lipase HA. The molecular weight of B. terrestris lipase BT-1 was approximately 30 kDa, the pH optimum was 8.3, and the temperature optimum was 50°C. Lipase BT-1 showed a notable preference for C8-C10 p-nitrophenyl esters, with the highest activity toward p-nitrophenyl caprylate (C8). The Michaelis constant (Km) and maximum reaction rate (Vmax) for p-nitrophenyl laurate hydrolysis were Km = 0.0011 mM and Vmax = 0.15 U/mg. CONCLUSION: This is the first report describing neutral lipase from the labial gland of B. terrestris. Our findings help increase understanding of its possible function in the labial gland.

The carrot psyllid, Trioza apicalis Forster (Homoptera, Psylloidea), is a pest that attacks carrots, especially in northern Europe. After hibernation on shelter plants, the adults migrate to the host plants, carrot seedlings, in early summer, shortly after the plants have emerged. Both adults and nymphs cause damage to the carrot (Markkula et al., 1976). The saliva injected by adults during feeding causes curling of green plant parts and nymphal feeding causes reduction of root growth.

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 species that are phylogenetically related (Bombus terrestris and B. lucorum), and the other including species that interact ecologically (B. terrestris and its specific nest inquiline B. vestalis). For each bumblebee species, we characterized the patterns of variation and differentiation of insular (Corsican) vs. mainland (European) populations (i) with four genes (nuclear and mitochondrial, 3781 bp) and (ii) in the chemical composition of male marking secretions (MMS), a key trait for mate attraction in bumblebees, by gas chromatography-mass spectrometry (GC-MS). Our results provide evidence for genetic differentiation in Corsican bumblebees and show that, contrary to theoretical expectations, island populations of bumblebees exhibit levels of genetic variation similar to the mainland populations. Likewise, our comparative chemical analyses of MMS indicate that Corsican populations of bumblebees are significantly differentiated from the mainland yet they hold comparative levels of within-population MMS variability compared to the mainland. Therefore, insularity has led Corsican populations to diverge both genetically and chemically from their mainland relatives, presumably through genetic drift, but without a decrease of genetic diversity in island populations. We hypothesize that MMS divergence in Corsican bumblebees was driven by a persistent lack of gene flow with mainland populations and reinforced by the preference of Corsican females for sympatric (Corsican) MMS. The impoverished Corsican bumblebee fauna has not led to relaxation of stabilizing selection on MMS but to consistent differentiation chemical reproductive traits on the island. © 2013 Lecocq et al., SCOPUS: ar.j, info:eu-repo/semantics/published

International audience; Social parasites exploit the colony resources of social insects. Some of them exploit the host colony as a food resource or as a shelter whereas other species also exploit the brood care behavior of their social host. Some of these species have even lost the worker caste and rely completely on the host's worker force to rear their offspring. To avoid host defenses and bypass their recognition code, these social parasites have developed several sophisticated chemical infiltration strategies. These infiltration strategies have been highly studied in several hymenopterans. Once a social parasite has successfully entered a host nest and integrated its social system, its emerging offspring still face the same challenge of avoiding host recognition. However, the strategy used by the offspring to survive within the host nest without being killed is still poorly documented. In cuckoo bumblebees, the parasite males completely lack the morphological and chemical adaptations to social parasitism that the females possess. Moreover, young parasite males exhibit an early production of species-specific cephalic secretions, used as sexual pheromones. Host workers might thus be able to recognize them. Here we used a bumblebee host-social parasite system to test the hypothesis that social parasite male offspring exhibit a chemical defense strategy to escape from host aggression during their intranidal life. Using behavioral assays, we showed that extracts from the heads of young cuckoo bumblebee males contain a repellent odor that prevents parasite males from being attacked by host workers. We also show that social parasitism reduces host worker aggressiveness and helps parasite offspring acceptance

Amaryllidaceae species are known as ornamental plants. Some contain galanthamine, an acetylcholinesterase inhibitor. The chemical composition of the alkaloid extract of bulbs of Nerine bowdenii Watson has been analyzed by means of GC/MS. Twenty-two compounds were detected and nineteen of them identified, one of which was belladine. The alkaloid extract showed promising cholinesterase inhibitory activities against human blood acetylcholinesterase (HuAChE; IC50= 87.9±3.5 μg/mL) and human plasma butyrylcholinesterase (HuBuChE; IC50 = 14.8±1.1 μg/mL). Belladine inhibited HuAChE and HuBuChE in a dose-dependent manner with IC50 values of 781±12.5 μM and 284.8±4.2 μM, respectively.

Many methods, based on morphological, molecular or chemical characters, have been used to address the question of species taxonomic status. Integrative taxonomy aims to define stronger supported taxonomic hypotheses by considering complementary datasets from different characters. By following an integrative approach, the present study includes molecular, chemical and morphological criteria to establish the taxonomic status of two rare and doubtful cuckoo bumblebee taxa: Bombus (Psithyrus) barbutellus and Bombus (Psithyrus) maxillosus. These two sympatric taxa are discriminated by few morphological criteria (mainly wing darkness and hair length). We used these morphological character diagnoses to establish an a priori status of our samples (23 specimens). We developed a combined molecular dataset from one nuclear gene, elongation factor 1α (EF-1α), and one mitochondrial gene, cytochrome c oxidase subunit I (COI), spanning 1623 bp, and a chemical dataset of sexual marking pheromones (73 compounds). The molecular data were subjected to maximum-likelihood and Bayesian phylogenetic inference under partitioned model and maximum parsimony. The chemical data were analysed by clustering and the two-group k-means method to test divergences between the two species. The resulting phylogenetic trees show no consistent divergence between the two taxa. Moreover, we found no divergence in the sexual marking pheromones in the clustering and two-group k-means analyses. These converging results support the conspecificity of both taxa. Nonetheless, our determinations using the traditional morphological criteria separated our samples into two taxa. We conclude that the morphological criteria seem to relate to intraspecific variations: B. maxillosus is regarded as a syn.n. of B. barbutellus. © 2011 The Authors. Systematic Entomology © 2011 The Royal Entomological Society.

Background: Members of the subfamily Galleriinae have adapted to different selective environmental pressures by devising a unique mating process. Galleriinae males initiate mating by attracting females with either chemical or acoustic signals (or a combination of both modalities). Six compounds considered candidates for the sex pheromone have recently been identified in the wing gland extracts of Aphomia sociella males. Prior to the present study, acoustic communication had not been investigated. Signals mediating female attraction were likewise unknown. Methodology/Principal Findings: Observations of A. sociella mating behaviour and recordings of male acoustic signals confirmed that males initiate the mating process. During calling behaviour (stationary wing fanning and pheromone release), males disperse pheromone from their wing glands. When a female approaches, males cease calling and begin to produce ultrasonic songs as part of the courtship behaviour. Replaying of recorded courting songs to virgin females and a comparison of the mating efficiency of intact males with males lacking tegullae proved that male ultrasonic signals stimulate females to accept mating. Greenhouse experiments with isolated pheromone glands confirmed that the male sex pheromone mediates long-range female attraction. Conclusion/Significance: Female attraction in A. sociella is chemically mediated, but ultrasonic communication is also employed during courtship. Male ultrasonic songs stimulate female sexual display and significantly affect mating efficiency. Considerable inter-individual differences in song structure exist. These could play a role in female mate selection provided that the female’s ear is able to discern them. The A. sociella mating strategy described above is unique within the subfamily Galleriinae.