Meaningful Words in Crowd Noise: Searching for Volatiles Relevant to Carpenter Bees among the Diverse Scent Blends of Bee Flowers.

Olfactory cues constitute one of the most important plant-pollinator communication channels. Specific chemical components can be associated with specific pollinator functional groups due to pollinator-mediated selection on flower volatile (FV) emission. Here, we used multivariate analyses of FV data to detect an association between FVs and the worldwide distributed pollinator group of the carpenter bees (Xylocopa spp.). We compiled FVs of 29 plant species: 9 pollinated by carpenter bees, 20 pollinated by other bee pollinator functional groups. We tested whether FV emission differed between these groups. To rule out any phylogenetic bias in our dataset, we tested FV emission for phylogenetic signal. Finally, using field assays, we tested the attractive function of two FVs found to be associated with carpenter bees. We found no significant multivariate difference between the two plant groups FVs. However, seven FVs (five apocarotenoid terpenoids, one long-chain alkane and one benzenoid) were significantly associated with carpenter bee pollination, thus being "predictor" compounds of pollination by this pollinator functional group. From those, ß-ionone and (E)-methyl cinnamate presented the highest indicator values and had their behavioural function assessed in field assays. Phylogenetic signal for FVs emission was weak, suggesting that their emission could result from pollinator-mediated selection. In field assays, the apocarotenoid ß-ionone attracted carpenter bees, but also bees from other functional groups. The benzenoid (E)-methyl cinnamate did not attract significant numbers of pollinators. Thus, ß-ionone functions as a non-specific bee attractant, while apocarotenoid FVs emerge as consistent indicators of pollination by large food-foraging bees among bee-pollinated flowers.

Foraging strategies and physiological adaptations in large carpenter bees.

Large carpenter bees are charismatic and ubiquitous flower visitors in the tropics and sub-tropics. Unlike honeybees and bumblebees that have been popular subjects of extensive studies on their neuroethology, behaviour and ecology, carpenter bees have received little attention. This review integrates what is known about their foraging behaviour as well as sensory, physiological and cognitive adaptations and is motivated by their versatility as flower visitors and pollinators. This is evident from their extremely generalist foraging and adeptness at handling diverse flower types as legitimate pollinators and as illegitimate nectar robbers. They purportedly use traplining to forage between isolated patches and are long-distance flyers over several kilometres suggesting well-developed spatial learning, route memory and navigational capabilities. They have a broad range of temperature tolerance and thermoregulatory capabilities which are likely employed in their forays into crepuscular and nocturnal time periods. Such temporal extensions into dim-light periods invoke a suite of visual adaptations in their apposition optics. Thus, we propose that carpenter bees are an excellent though understudied group for exploring the complex nature of plant-pollinator mutualisms from ecological and mechanistic perspectives.

Nesting habits influence population genetic structure of a bee living in anthropogenic disturbance.

While most organisms are negatively affected by anthropogenic disturbance, a few species thrive in landscapes altered by humans. Typically, native bees are negatively impacted by anthropogenic environmental change, including habitat alteration and climate change. Here, we investigate the population structure of the eastern carpenter bee Xylocopa virginica, a generalist pollinator with a broad geographic range spanning eastern North America. Eastern carpenter bees now nest almost exclusively in artificial wooden structures, linking their geographic distribution and population structure to human activities and disturbance. To investigate the population structure of these bees, we sampled females from 16 different populations from across their range. Nine species-specific microsatellite loci showed that almost all populations are genetically distinct, but with high levels of genetic diversity and low levels of inbreeding overall. Broadly speaking, populations clustered into three distinct genetic groups: a northern group, a western group and a core group. The northern group had low effective population sizes, decreased genetic variability and the highest levels of inbreeding in the data set, suggesting that carpenter bees may be expanding their range northward. The western group was genetically distinct, but lacked signals of a recent range expansion. Climatic data showed that summer and winter temperatures explained a significant amount of the genetic differentiation seen among populations, while precipitation did not. Our results indicate that X. virginica may be one of the rare 'anthrophilic' species that thrive in the face of anthropogenic disturbance.

Asymmetric competition for nectar between a large nectar thief and a small pollinator: an energetic point of view.

There are two alternative hypotheses related to body size and competition for restricted food sources. The first one supposes that larger animals are superior competitors because of their increased feeding abilities, whereas the second one assumes superiority of smaller animals because of their lower food requirements. We examined the relationship between two unrelated species of different size, drinking technique, energy requirements and roles in plant pollination system, to reveal the features of their competitive interaction and mechanisms enabling their co-existence while utilising the same nectar source. We observed diurnal feeding behaviour of the main pollinator, the carpenter bee Xylocopa caffra and a nectar thief, the northern double-collared sunbird Cinnyris reichenowi on 19 clumps of Hypoestes aristata (Acanthaceae) in Bamenda Highlands, Cameroon. For comparative purpose, we established a simplistic model of daily energy expenditure and daily energy intake by both visitor species assuming that they spend all available daytime feeding on H. aristata. We revealed the energetic gain-expenditure balance of the studied visitor species in relation to diurnal changes in nectar quality and quantity. In general, smaller energy requirements and related ability to utilise smaller resources made the main pollinator X. caffra competitively superior to the larger nectar thief C. reichenowi. Nevertheless, sunbirds are endowed with several mechanisms to reduce asymmetry in exploitative competition, such as the use of nectar resources in times of the day when rivals are inactive, aggressive attacks on carpenter bees while defending the nectar plants, and higher speed of nectar consumption.

First Reported Case of Fatal Stinging by the Large Carpenter Bee Xylocopa tranquebarica.

In the order Hymenoptera, bees, hornets, and wasps are well-known stinging insects whose envenoming can be fatal. Their stinging attacks are common in rural and forested areas of Sri Lanka. However, fatal stinging by the large-bodied carpenter bees is unreported. We report the first known case of a fatal sting by the large carpenter bee, Xylocopa tranquebarica, in a forested area in Puttalam (North Western Province) in the dry zone of Sri Lanka. A 59-year-old healthy male manual laborer accompanied by a fellow worker had been fixing a fence on a coconut estate bordering a forested area when a flying insect emerged from a dead tree trunk and stung him on his face. His coworker, who was watching the incident, killed the insect. The victim complained of immediate intense pain in the face and collapsed on the ground just after resuming work after 10 minutes of resting. He was found dead on admission to the hospital 90 minutes later. Autopsy showed normal coronary arteries and heart, but the lungs were slightly congested and contained secretions in the bronchi. Acute anaphylaxis was the most likely cause of death. This case presents the habitat, morphology, attack pattern, and the medical importance of large carpenter bees.

Variation in floral morphology, histochemistry, and floral visitors of three sympatric morning glory species.

Three morning glory species in the genus Argyreia Lour., A. lycioides (Choisy) Traiperm & Rattanakrajang, A. mekongensis Gagnep & Courchet, and A. versicolor (Kerr) Staples & Traiperm, were found co-occurring and co-flowering. Argyreia mekongensis and A. versicolor are rare, while A. lycioides is near threatened and distributed throughout Myanmar and Thailand. We investigated key floral characters (floral morphology and phenology, as well as the micromorphology of the floral nectary disc and staminal trichomes) and screened for important chemical compounds hypothesized to contribute to pollinator attraction. Our findings demonstrate that some aspects of floral morphology (e.g., corolla size, limb presence, and floral color) of the three studied congeners exhibit significant differences. Moreover, pollinator composition appears to be influenced by floral shape and size; morning glory species with wider corolla tubes were pollinated by larger bees. The morphology of the floral nectary disc was similar in all species, while variation in staminal trichomes was observed across species. Glandular trichomes were found in all three species, while non-glandular trichomes were found only in A. versicolor. Histochemical results revealed different compounds in the floral nectary and staminal trichomes of each species, which may contribute to both floral attraction and defense. These findings demonstrate some segregation of floral visitors among sympatric co-flowering morning glory species, which appears to be influenced by the macro- and micromorphology of flowers and their chemical compounds. Moreover, understanding the floral morphology and chemical attractants of these sympatric co-flowering Argyreia species may help to maintain their common pollinators in order to conserve these rare and endangered species, especially A. versicolor.

Near extinct Argyreia versicolor and rare Argyreia mekongensis are dependent on carpenter bee pollinators.

Argyreia versicolor and Argyreia mekongensis are extremely rare plant species. The former had not been seen for nearly 100 years until two individuals were found in Thailand in 2018, and only a handful of populations are known for the latter. The aims of this study were to examine the breeding systems of A. versicolor and A. mekongensis using pollination experiments and to determine their potential pollinators via floral observations. Our controlled pollination experiments uncovered the self-incompatibility of both species. Pollinator censuses indicated that females of two carpenter bee species, Xylocopa aestuans and Xylocopa latipes, were the predominant floral visitors for both Argyreia species. Our observations confirmed a harmonious match between the floral shape of both Argyreia species and the body sizes of these pollinators, ensuring effective pollen transfer and validating their role as putative pollinators. In line with the high frequency of pollinator visits observed, our controlled pollination experiments found no evidence of pollen limitation under field conditions. The findings of this study hold significance for the conservation of these endangered species, yet the situation is dire for A. versicolor, with one of the two individuals under study recently lost. Hence, it is crucial to intensify monitoring efforts for the species, aiming to identify additional individuals for potential inclusion in an ex-situ conservation program. Simultaneously, safeguarding the habitat of these plant species and their pollinators will be critical.

Detection of Apicystis bombi (Apicomplexa: Neogregarinorida) in carpenter bees of Argentina.

Historically, the neogregarine Apicystis bombi was isolated almost exclusively from bumble bees (Bombus spp.) where it disrupts adipose tissue, increasing hosts' mortality rates. Records in solitary bees are scarce worldwide. To check for its presence in carpenter bees (genus Xylocopa), campaigns were performed in Argentina capturing 154 individuals of five species (X. augusti, X. splendidula, X. atamisquensis, X. frontalis, X. nigrocincta). The presence of A. bombi was detected by molecular means in X. augusti, X. atamisquensis, and X. nigrocincta in four of the nine provinces screened. The pathogenesis and eventual impact that A. bombi may cause in individuals or populations of Xylocopa species remain unknown. The presence of A. bombi in northern Argentina would be contradictory to the hypothesis that its occurrence is the exclusive result of its introduction to South America through invasive, infected exotic bumble bees.

Wild bees are exposed to low levels of pesticides in urban grasslands and community gardens.

Globally documented wild bee declines threaten sustainable food production and natural ecosystem functioning. Urban environments are often florally abundant, and consequently can contain high levels of pollinator diversity compared with agricultural environments. This has led to the suggestion that urban environments are an increasingly important habitat for pollinators. However, pesticides, such as commercial bug sprays, have a range of lethal and sub-lethal impacts on bees and are widely available for public use, with past work indicating that managed bees (honeybees and bumblebees) are exposed to a range of pesticides in urban environments. Despite this, we still have a poor understanding of (i) whether wild bees foraging in urban environments are exposed to pesticides and (ii) if exposure differs between genera. Here we assessed pesticide exposure in 8 bee genera foraging across multiple urban landscapes. We detected 13 different pesticides, some at concentrations known to have sub-lethal impacts on pollinators. Both the likelihood of pesticides being detected, and the concentrations observed, were higher for larger bees, likely due to their greater foraging ranges. Our results suggest that restricting agrochemical use in urban environments, where the economic benefits are limited, is a simple way to reduce anthropogenic stress on wild bees.

The gut microbiome of solitary bees is mainly affected by pathogen assemblage and partially by land use.

Pollinators, including solitary bees, are drastically declining worldwide. Among the factors contributing to this decline, bee pathogens and different land uses are of relevance. The link between the gut microbiome composition and host health has been recently studied for social pollinators (e.g. honeybees), whereas the information related to solitary bees is sparse. This work aimed at the characterization of the gut microbiome of the solitary bees Xylocopa augusti, Eucera fervens and Lasioglossum and attempted to correlate the gut microbial composition with the presence and load of different pathogens and land uses. Solitary bees were sampled in different sites (i.e. a farm, a natural reserve, and an urban plant nursery) showing different land uses. DNA was extracted from the gut, 16S rRNA gene amplified and sequenced. Eight pathogens, known for spillover from managed bees to wild ones, were quantified with qPCR. The results showed that the core microbiome profile of the three solitary bees significantly varied in the different species. Pseudomonas was found as the major core taxa in all solitary bees analyzed, whereas Lactobacillus, Spiroplasma and Sodalis were the second most abundant taxa in X. augusti, E. fervens and Lasioglossum, respectively. The main pathogens detected with qPCR were Nosema ceranae, Nosema bombi and Crithidia bombi, although differently abundant in the different bee species and sampling sites. Most microbial taxa did not show any correlation with the land use, apart from Snodgrassella and Nocardioides, showing higher abundances on less anthropized sites. Conversely, the pathogens species and load strongly affected the gut microbial composition, with Bifidobacterium, Apibacter, Serratia, Snodgrassella and Sodalis abundance that positively or negatively correlated with the detected pathogens load. Therefore, pathogens presence and load appear to be the main factor shaping the gut microbiome of solitary bees in Argentina.

Pollinator Efficacy in Yellow Passion Fruit (Passiflora edulis f. flavicarpa Deg., Passifloraceae).

A pollinator's efficacy is the result obtained from a single visit by a species and is often used to measure the importance of different species of floral visitors as pollinators. Therefore, this study aimed to measure the efficacy of fruit and seed set in Passiflora edulis f. flavicarpa Deg. (Passifloraceae) by manual cross-pollination, natural pollination and by Xylocopa (Neoxylocopa) frontalis (Olivier 1789), performed through a single and two visits, to evaluate if there is occurrence of pollen limitation and pollinators' limitation in the studied crop fields. Four different treatments were performed: (1) manual cross-pollination (n = 37 flowers); (2) natural pollination (n = 52 flowers); (3) pollination by a single visit of X. frontalis (n = 41 flowers); and (4) pollination by two visits of X. frontalis (n = 31 flowers). We verified that fruit set occurred in all the treatments performed. Fruit set rate by manual cross-pollination was significantly higher than that obtained under natural conditions indicating the occurrence of pollen limitation and pollinators' limitation under natural pollination. Regarding the number of seeds, analysis of variance (ANOVA) did not indicate a significant difference between the mean seed set for the different types of pollination evaluated. The management of occupied nests, the introduction of trap-nests, and the conservation of native vegetation in areas close to the yellow passion fruit crops can increase pollinators' population. The greater richness and abundance of pollinators are essential to promote a greater number of fruit and seed set in the yellow passion fruit crops.

Microbial abundance, composition, and function in nectar are shaped by flower visitor identity.

Microbial dispersal is essential for establishment in new habitats, but the role of vector identity is poorly understood in community assembly and function. Here, we compared microbial assembly and function in floral nectar visited by legitimate pollinators (hummingbirds) and nectar robbers (carpenter bees). We assessed effects of visitation on the abundance and composition of culturable bacteria and fungi and their taxonomy and function using shotgun metagenomics and nectar chemistry. We also compared metagenome-assembled genomes (MAGs) of Acinetobacter, a common and highly abundant nectar bacterium, among visitor treatments. Visitation increased microbial abundance, but robbing resulted in 10× higher microbial abundance than pollination. Microbial communities differed among visitor treatments: robbed flowers were characterized by predominant nectar specialists within Acetobacteraceae and Metschnikowiaceae, with a concurrent loss of rare taxa, and these resulting communities harbored genes relating to osmotic stress, saccharide metabolism and specialized transporters. Gene differences were mirrored in function: robbed nectar contained a higher percentage of monosaccharides. Draft genomes of Acinetobacter revealed distinct amino acid and saccharide utilization pathways in strains isolated from robbed versus pollinated flowers. Our results suggest an unrecognized cost of nectar robbing for pollination and distinct effects of visitor type on interactions between plants and pollinators. Overall, these results suggest vector identity is an underappreciated factor structuring microbial community assembly and function.

Documenting Potential Sunn Hemp (Crotalaria juncea L.) (Fabaceae) Pollinators in Florida.

Sunn hemp, Crotalaria juncea L., is a warm-season legume that can be planted in rotation to cash crops to add nitrogen and organic matter to the soils, for weed growth prevention, and to suppress nematode populations. Sunn hemp flowers also provide nectar and pollen for pollinators and enhance biological control by furnishing habitat for natural enemies. Experiments were conducted in Northern and North Central Florida to evaluate bee populations that visited flowers within mixed plots of sunn hemp and sorghum-sudangrass and plots of two sunn hemp germplasm lines. Collections of bees that visited 'AU Golden' and Tillage Sunn flowers indicated that Xylocopa virginica (L.) (Hymenoptera: Apidae), Xylocopa micans Lepeletier (Hymenoptera: Apidae), Megachile sculpturalis Smith (Hymenoptera: Megachilidae), Megachile mendica (Cresson) (Hymenoptera: Megachilidae), and Megachile georgica Cresson (Hymenoptera: Megachilidae) were present in large numbers in May through July and then again in October. Although Tillage Sunn seeds planted in March flowered in May, percent bloom and number of bee visits were low. Compared with short day sunn hemp cultivars, 'AU Golden' plants produced flowers early in the season to provide food and habitat for pollinators and have the potential to produce an abundant seed crop in Northern and North Central Florida.

Minimizing Bee (Hymenoptera: Apoidea) Bycatch in Japanese Beetle Traps.

Native and introduced bees were attracted to and captured in commercially available Japanese beetle, Popillia japonica Newman (Coleoptera: Scarabaeidae), traps baited with floral lure components: geraniol, eugenol, and phenethyl propionate [PEP] in Rhode Island, Ohio, and Tennessee. Studies in Rhode Island showed that Bombus impatiens Cresson (Hymenoptera: Apidae) was significantly more attracted to geraniol alone and as a component in floral lure blends than to either eugenol or PEP alone. Xylocopa virginica (L.) (Hymenoptera: Apidae) was more selective in being primarily attracted to traps baited with higher amounts of geraniol in 2016. Removing geraniol from the floral lure blend did not significantly reduce Japanese beetle captures in 2017 and 2018 in Rhode Island and Ohio but did significantly reduce bee captures in Rhode Island in 2017 and 2018. Green, black, brown, and red traps captured significantly fewer bees than clear or standard yellow vane and green cage traps in 2018 in Rhode Island and Tennessee; however, there were no significant differences between Japanese beetle captures in any of the colored or clear traps. Our results show that using all green traps with a lure composed of eugenol and PEP and the Japanese beetle female produced sex pheromone can effectively capture Japanese beetles while minimizing bycatch of bees.

Effect of Corolla Slitting and Nectar Robbery by the Eastern Carpenter Bee (Hymenoptera: Apidae) on Fruit Quality of Vaccinium corymbosum L. (Ericales: Ericaceae).

Eastern carpenter bees, Xylocopa virginica (L.) (Hymenoptera: Apidae), are among the most abundant native bee visitors to highbush blueberry, Vaccinium corymbosum L., flowers in the northeastern United States, and they sometimes display corolla-slitting behavior to rob nectar. We studied foraging behavior of X. virginica on 14 blueberry cultivars in an experimental planting in Rhode Island, and assessed factors related to slitting frequency, and the effects of slitting on fruit set and blueberry quality. Among 14 cultivars in bloom, an average of 35% (range 16-67%) of flowers were slit in 2017, and 39% (range 20-62%) in 2018. Factors that affected the proportion of corollas slit included cultivar, anther length, flower volume, and number of days in bloom at or above 15°C. Corolla slitting did not affect fruit set. Average weight and percent soluble solids of fruit resulting from slit and non-slit corollas did not differ significantly in two early- ('Bluehaven', 'Earliblue'), two mid- ('Collins', 'Bluecrop'), and two late-season ('Herbert', 'Lateblue') ripening cultivars in 2017. In 2018, average fruit weight and percent soluble solids resulting from slit and non-slit flowers did not differ significantly in most cultivars, but slit corollas resulted in berries with greater mass in two cultivars, 'Bluehaven' and 'Collins'. 'Collins' fruit from non-slit corollas had a significantly higher percentage of soluble solids at maturity than fruit from slit corollas in 2018. Corolla slitting and nectar robbery by X. virginica did not have a significant negative effect on fruit quality under the described growing conditions and pollinator community.

Association Between Density of Foraging Bees and Fruit Set in Commercial Fields of Rabbiteye Blueberries (Ericales: Ericaceae) in Louisiana and Mississippi.

Field-scale data on the relationship between pollinator activity and fruit set are scarce for rabbiteye blueberries (Vaccinium virgatum Aiton). We measured the densities of Apis mellifera L. (Hymenoptera: Apidae), Habropoda laboriosa F. (Hymenoptera: Apidae), Bombus Latreille (Hymenoptera: Apidae) spp., and Xylocopa virginica L. (Hymenoptera: Apidae) in 7-21 commercial fields during each of 3 yr in Louisiana and Mississippi. Foraging bees were counted on 10 'Tifblue' bushes per field on 2 d during bloom, and the density of bees per flower was calculated based on the number of flowers open during the counts. Fruit set was measured 30 d after bloom. The impact of foraging activity on fruit set was inconsistent when densities of either all foragers or foragers of individual taxa were considered. Strong associations were observed only in 2001, with fruit set increased by H. laboriosa and Bombus and with a weaker contribution by A. mellifera. Floral robbery by X. virginica had no measurable negative effects. Populations of H. laboriosa were more consistent than those of other bees across sites. Managed colonies of A. mellifera were added at two densities (12.5 or 2.5 colonies per hectare) in seven fields each in 2001. These supplemental bees did not result in greater forager densities or fruit set in stocked fields. The observations show the challenge of field-scale pollination tests but provide an initial framework for rabbiteye blueberry growers to assess the availability of foraging bees early in bloom to help decide whether to add supplemental A. mellifera to try to enhance pollination if populations of non-Apis bees are low.

Isolation from natural habitat reduces yield and quality of passion fruit.

Loss and fragmentation of native vegetation negatively affect crop pollinators and productivity of several crop species. The yellow passion fruit is an excellent model to investigate this issue, because its main pollinators are sensitive to deforestation. Seasonality also influences fruit set of crop species that are pollinated by bees. Climate determines plant flowering patterns and consequently affects pollinator activity. Little is known on effects of pollinators on crop quality in general, and particularly of many tropical fruits that have multiple fruiting seasons throughout the year, such as passion fruit. Our hypothesis is that the distance to the native vegetation and climate seasonality affect the pollination and fruit production of cultivated, hermaphrodite, self-incompatible, protandrous species that depend on large-sized bees to set fruit. We observed flowers of the yellow passion fruit in eight areas at different distances (600-4,000 m) from a dry seasonal forest (Caatinga). We compared the frequency of the main floral visitor (pollinators and robbers) visits and fruit set among areas at the beginning and end of the dry and rainy seasons. Xylocopa species were pollinators, and Apis mellifera, Trigona spinipes and a hummingbird were robbers. Xylocopa visits diminished with increasing distance to native remnants, converse to what was observed for the robbers at the beginning of the dry season. Fruit set was higher at the beginning of the dry season. The distance to the forest affected quality of fruits in terms of length, diameter and skin thickness, which all decreased with increase in remnant distance. Our results show that insect pollination is higher in the dry season, increasing profitability and reducing labour costs for the producer. Considering the influence of distance to native vegetation on pollination, robbery and fruit quality, our study reinforces the necessity for conservation of native vegetation remnants.

Bifidobacterium xylocopae sp. nov. and Bifidobacterium aemilianum sp. nov., from the carpenter bee (Xylocopa violacea) digestive tract.

Social bees harbor a community of gut mutualistic bacteria, among which bifidobacteria occupy an important niche. Recently, four novel species have been isolated from guts of different bumblebees, thus allowing to suppose that a core bifidobacterial population may be present in wild solitary bees. To date there is sparse information about bifidobacteria in solitary bees such as Xylocopa and Osmia spp., this study is therefore focused on the isolation and characterization of bifidobacterial strains from solitary bees, in particular carpenter bee (Xylocopa violacea), builder bee (Osmia cornuta), and red mason bee (Osmia rufa). Among the isolates from Osmia spp. no new species have been detected whereas among Xylocopa isolates four strains (XV2, XV4, XV10, XV16) belonging to putative new species were found. Isolated strains are Gram-positive, lactate- and acetate-producing and possess the fructose-6-phosphate phosphoketolase enzyme. Full genome sequencing and genome annotation were performed for XV2 and XV10. Phylogenetic relationships were determined using partial and complete 16S rRNA sequences and hsp60 restriction analysis that confirmed the belonging of the new strains to Bifidobacterium genus and the relatedness of the strains XV2 and XV10 with XV16 and XV4, respectively. Phenotypic tests were performed for the proposed type strains, reference strains and their closest neighbor in the phylogenetic tree. The results support the proposal of two novel species Bifidobacterium xylocopae sp. nov. whose type strain is XV2 (=DSM 104955T=LMG 30142T), reference strain XV16 and Bifidobacterium aemilianum sp. nov. whose type strain is XV10 (=DSM 104956T=LMG 30143T), reference strain XV4.

Foraging behavior and pollination of carpenter bees Xylocopa spp. (Hymenoptera: Apidae).

Large carpenter bees (the genus Xylocopa), as an important group of bees (Apidae), are common visitors to flowering plants in tropics and subtropics. Their foraging behavior is characterized by long season of activity, high diversity of foraging plants, tolerance of high temperatures, activity under low illumination levels, and buzz pollination. These traits make them to be attractive pollinators for agricultural pollination in hot climates, especially in greenhouses, night-blooming plants, and some Solanum. In recent years, large carpenter bees have been demonstrated have efficient pollination service in blueberries, passion flower, runner bean, greenhouse tomatoes and greenhouse melons in foreign countries. However, evidence for their importance and effectiveness as crop pollinators is lacking for most plant species in China. This article reviewed the research progress on foraging behavior and pollination of Xylocopa, with the aim to provide a theoretical basis for the conservation management and utilization of large carpenter bees.

Multiple origins of sexual dichromatism and aposematism within large carpenter bees.

The evolution of reversed sexual dichromatism and aposematic coloration has long been of interest to both theoreticians and empiricists. Yet despite the potential connections between these phenomena, they have seldom been jointly studied. Large carpenter bees (genus Xylocopa) are a promising group for such comparative investigations as they are a diverse clade in which both aposematism and reversed sexual dichromatism can occur either together or separately. We investigated the evolutionary history of dichromatism and aposematism and a potential correlation of these traits with diversification rates within Xylocopa, using a newly generated phylogeny for 179 Xylocopa species based on ultraconserved elements (UCEs). A monochromatic, inconspicuous ancestor is indicated for the genus, with subsequent convergent evolution of sexual dichromatism and aposematism in multiple lineages. Aposematism is found to covary with reversed sexual dichromatism in many species; however, reversed dichromatism also evolved in non-aposematic species. Bayesian Analysis of Macroevolutionary Models (BAMM) did not show increased diversification in any specific clade in Xylocopa, whereas support from Hidden State Speciation and Extinction (HiSSE) models remained inconclusive regarding an association of increased diversification rates with dichromatism or aposematism. We discuss the evolution of color patterns and diversification in Xylocopa by considering potential drivers of dichromatism and aposematism.