Xylocopa caerulea and Xylocopa auripennis harbor a homologous gut microbiome related to that of eusocial bees.

Background: Eusocial bees, such as bumblebees and honey bees, harbor host-specific gut microbiota through their social behaviors. Conversely, the gut microbiota of solitary bees is erratic owing to their lack of eusocial activities. Carpenter bees (genus Xylocopa) are long-lived bees that do not exhibit advanced eusociality like honey bees. However, they often compete for nests to reproduce. Xylocopa caerulea and Xylocopa auripennis are important pollinators of wild plants on Hainan Island. Whether they have host-specific bacteria in their guts similar to eusocial bees remains unknown. Methods: We targeted the bacterial 16S rRNA V3-V4 region to investigate the diversity of bacterial symbionts in the fore-midgut and hindgut of two carpenter bees, X. caerulea and X. auripennis. Results: A maximum of 4,429 unique amplicon sequence variants (ASVs) were detected from all samples, belonging to 10 different phyla. X. caerulea and X. auripennis shared similar bacterial community profiles, with Lactobacillaceae, Bifidobacteriaceae, and Orbaceae being dominant in their entire guts. X. caerulea and X. auripennis harbor a highly conserved core set of bacteria, including the genera Candidatus Schmidhempelia and Bombiscardovia. These two bacterial taxa from carpenter bees are closely related to those isolated from bumblebees. The LEfSe analysis showed that Lactobacillaceae, Bifidobacteriaceae, and the genus Bombilactobacillus were significantly enriched in the hindguts of both carpenter bees. Functional prediction suggested that the most enriched pathways were involved in carbohydrate and lipid metabolism. Conclusions: Our results revealed the structure of the gut microbiota in two carpenter bees and confirmed the presence of some core bacterial taxa that were previously only found in the guts of social bees.

Symbiosis of Carpenter Bees with Uncharacterized Lactic Acid Bacteria Showing NAD Auxotrophy.

Eusocial bees (such as honey bees and bumble bees) harbor core gut microbiomes that are transmitted through social interaction between nestmates. Carpenter bees are not eusocial; however, recent microbiome analyses found that Xylocopa species harbor distinctive core gut microbiomes. In this study, we analyzed the gut microbiomes of three Xylocopa species in Japan between 2016 and 2021 by V1 to V2 region-based 16S rDNA amplicon sequencing, and 14 candidate novel species were detected based on the full-length 16S rRNA gene sequences. All Xylocopa species harbor core gut microbiomes consisting of primarily lactic acid bacteria (LAB) that were phylogenetically distant from known species. Although they were difficult to cultivate, two LAB species from two different Xylocopa species were isolated by supplementing bacterial culture supernatants. Both genomes exhibited an average LAB genome size with a large set of genes for carbohydrate utilization but lacked genes to synthesize an essential coenzyme NAD, which is unique among known insect symbionts. Our findings of phylogenetically distinct core LAB of NAD auxotrophy reflected the evolution of Xylocopa-restricted bacteria retention and maintenance through vertical transmission of microbes during solitary life. We propose five candidate novel species belonging to the families Lactobacillaceae and Bifidobacteriaceae, including a novel genus, and their potential functions in carbohydrate utilization. IMPORTANCE Recent investigations found unique microbiomes in carpenter bees, but the description of individual microbes, including isolation and genomics, remains largely unknown. Here, we found that the Japanese Xylocopa species also harbor core gut microbiomes. Although most of them were difficult to isolate a pure colony, we successfully isolated several strains. We performed whole-genome sequencing of the isolated candidate novel species and found that the two Lactobacillaceae strains belonging to the Xylocopa-specific novel LAB clade lack the genes for synthesizing NAD, a coenzyme central to metabolism in all living organisms. Here, we propose a novel genus for the two LAB species based on very low 16S rRNA gene sequence similarities and genotypic characters.

Intrafloral patterns of color and scent in Capparis spinosa L. and the ghosts of its selection past.

PREMISE: Capparis spinosa is a widespread charismatic plant, in which the nocturnal floral habit contrasts with the high visitation by diurnal bees and the pronounced scarcity of hawkmoths. To resolve this discrepancy and elucidate floral evolution of C. spinosa, we analyzed the intrafloral patterns of visual and olfactory cues in relation to the known sensory biases of the different visitor guilds (bees, butterflies, and hawkmoths). METHODS: We measured the intrafloral variation of scent, reflectance spectra, and colorimetric properties according to three guilds of known visitors of C. spinosa. Additionally, we sampled visitation rates using a motion-activated camera. RESULTS: Carpenter bees visited the flowers eight times more frequently than nocturnal hawkmoths, at dusk and in the following morning. Yet, the floral headspace of C. spinosa contained a typical sphingophilous scent with high emission rates of certain monoterpenes and amino-acid derived compounds. Visual cues included a special case of multisensory nectar guide and color patterns conspicuous to the visual systems of both hawkmoths and bees. CONCLUSIONS: The intrafloral patterns of sensory stimuli suggest that hawkmoths have exerted strong historical selection on C. spinosa. Our study revealed two interesting paradoxes: (a) the flowers phenotypically biased towards the more inconsistent pollinator; and (b) floral display demands an abundance of resources that seems maladaptive in the habitats of C. spinosa. The transition to a binary pollination system accommodating large bees has not required phenotypic changes, owing to specific eco-physiological adaptations, unrelated to pollination, which make this plant an unusual case in pollination ecology.

Carpenter Bees (Xylocopa) Harbor a Distinctive Gut Microbiome Related to That of Honey Bees and Bumble Bees.

Eusocial corbiculate bees, including bumble bees and honey bees, maintain a socially transmitted core gut microbiome that contributes to digestion and pathogen defense. In contrast, solitary bees, which have fewer opportunities for direct interhost transmission, typically have less consistent microbiomes dominated by bacteria associated with pollen and food reserves. Carpenter bees (genus Xylocopa) are long-lived bees that are not eusocial but that often live in shared nesting sites. We characterized gut microbiomes for Xylocopa micans, X. mexicanorum, X. tabaniformis parkinsoniae, and X. virginica and for five solitary bee species from other genera (Andrena, Habropoda, Megachile, and Svastra), sampled in the same localities in central Texas. Unexpectedly, all four Xylocopa species had microbiomes dominated by bacterial lineages previously known only from social bees or other insect groups. Microbiomes were similar across three Xylocopa species and included lineages in the families Bifidobacteriaceae, Orbaceae, Lactobacillaceae, Pseudomonadaceae, and Enterobacteriaceae. In contrast, X. virginica had a distinct microbiome dominated by the genus Bombilactobacillus, a group abundant in guts of eusocial bees. Phylogenetic analyses support a past transfer of bacterial lineages into Xylocopa from bumble bees or honey bees. Gut microbiome compositions of Xylocopa species were distinct from those of other co-occurring solitary bees that had variable gut microbiomes dominated by bacteria from environmental sources. IMPORTANCE Gut microbiomes from social bees, such as honey bees and bumble bees, are conserved and consist of host-restricted bacteria that are transmitted among sterile female workers within a colony and that are important to the health of these key insect pollinators. In contrast, solitary bee species typically have more erratic, environmentally acquired microbiomes. Carpenter bees (genus Xylocopa) can be solitary as they lack a worker caste, and each female can excavate nests and raise offspring alone, although females are often social share nests at least in some species. This study showed that the gut microbiomes of four Xylocopa species have distinctive and consistent compositions and are dominated by bacterial lineages previously known from honey bees and bumble bees. Thus, eusociality is not required for bees to maintain a specialized, host-restricted gut microbiome. These findings suggest that gut bacteria are transmitted at shared nesting sites and that they play a role in host ecology.

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.

Connective appendages in Huberia bradeana (Melastomataceae) affect pollen release during buzz pollination.

Floral structures, such as stamen appendages, play crucial roles in pollinator attraction, pollen release dynamics and, ultimately, the reproductive success of plants. The pollen-rewarding, bee buzz-pollinated flowers of Melastomataceae often bear conspicuous staminal appendages. Surprisingly, their functional role in the pollination process remains largely unclear. We use Huberia bradeana Bochorny & R. Goldenb. (Melastomataceae) with conspicuously elongated, twisted stamen appendages to investigate their functional role in the pollination process. We studied the effect of stamen appendages on pollinator behaviour and reproductive success by comparing manipulated flowers (appendages removed) with unmanipulated flowers. To assess bee pollinator behaviour, we measured three properties of buzzes (vibrations) produced by bees on Huberia flowers: frequency, duration and number of buzzes per flower visit. We measured male and female reproductive success by monitoring pollen release and deposition after single bee visits. Finally, we used artificial vibrations and laser vibrometry to assess how flower vibrational properties change with the removal of stamen appendages. Our results show that the absence of staminal appendages does not modify bee buzzing behaviour. Pollen release was higher in unmanipulated flowers, but stigmatic pollen loads differ only marginally between the two treatments. We also detected lower vibration amplitudes in intact flowers as compared to manipulated flowers in artificial vibration experiments. The presence of connective appendages are crucial in transmitting vibrations and assuring optimal pollen release. Therefore, we propose that the high diversity of colours, shapes and sizes of connective appendages in buzz-pollinated flowers may have evolved by selection through male fitness.

Bacterial Communities in Three Parts of Intestinal Tracts of Carpenter Bees (Xylocopa tenuiscapa).

This study investigated different bacterial communities in three intestinal parts (foregut, midgut and hindgut) of Xylocopatenuiscapa to understand the roles of gut bacteria. Our phylogenetic analysis revealed that X. tenuiscapa is closely related to Xylocopa latipes. The 16S rRNA gene in the genomic DNA samples from the gut was examined by illumina (Solexa) and a total of 998 operational taxonomic unit (OTUs) clusters were found. Taxonomic classification identified 16 bacterial phyla and unclassified bacteria. The dominant bacteria taxa in the three parts of X. tenuiscapa gut were Proteobacteria, Firmicutes, Bacteroidetes and Actinobacteria. In the foregut, Lactobacillales and Enterobacteriaceae were predominantly found. The population in the midgut was similar to that in the foregut, with the addition of Gilliamella, which was also abundant. The most dominant bacteria identified in the hindgut were similar to those in the midgut and Lactobacillales, Enterobacteriaceae, Gilliamella, Bifidobacteriaceae and Flavobacteriaceae appeared in abundance. Moreover, our results suggest that a community structure of bacteria in different parts of X. tenuiscapa's gut may be an important indicator of carpenter bees' health. This functional study of bacterial communities revealed significant differences among the three intestinal parts and is the first report of the gut bacteria structure in solitary bees.

Xylocopa sonorina Smith, 1874 from Vancouver, British Columbia, Canada (Hymenoptera: Apidae, Xylocopinae) with comments on its taxonomy.

BACKGROUND: Only one species of large carpenter bee, Xylocopa virginica (Linnaeus, 1771), has been recorded from Canada, albeit restricted to southern Ontario and Quebec. However, a single female specimen identified by Hurd in 1954 as X. varipuncta Patton, 1879 from British Columbia is in the C.A. Triplehorn Insect Collection at The Ohio State University (OSUC), suggesting that this species was accidentally introduced into coastal western Canada. As wood-nesters, many large carpenter bees are likely capable of expanding their range great distances by natural and unnatural transport methods while nesting inside suitable substrates, the presumed mode of transport into western Canada, and likely elsewhere. The ease at which the nests are transported has likely contributed to the nomenclatural and distributional ambiguity surrounding this species due to morphological similarities of specimens from North America, Hawaii, and several South Pacific islands. NEW INFORMATION: By comparing DNA barcodes of specimens from the western United States to specimens from Hawaii, we confirm the early opinion of P.H. Timberlake (Timberlake 1922) that specimens long established on the Hawaiian Islands are the same X. varipuncta from continental North America. Furthermore, these DNA barcode sequences also match those of specimens identified as X. sonorina Smith, 1874 from the French Polynesian and Samoan Islands, thus fully supporting the opinion of Groom et al. (2017) that all are likely conspecific. As X. sonorina, a species described from and likely introduced to Hawaii is the oldest name available, X. varipuncta is here placed into synonymy. Additional research will be needed to trace the timing and pathway of introduction and establishment of X. sonorina; it is presumed that the species is native to the southwestern United States but has been established in Hawaii since the mid-1800s. It is also established in French Polynesia, the Samoan Islands, and likely other south Pacific islands, with additional records of occurrence from Java, New Zealand, and now Canada.

A new species of Ceratina (Ceratinula) Moure, 1941, with notes on the taxonomy and distribution of Ceratina (Ceratinula) manni Cockerell, 1912, and an identification key for species of this subgenus known from Brazil (Hymenoptera, Apidae, Ceratinini).

A new species of the small carpenter bee, genus Ceratina (Ceratinula) Moure, from the Cerrado Biome in midwestern Brazil is described and illustrated. Ceratina (Ceratinula) fioreseana Oliveira, sp. nov. is easily distinguished from its congeners by the size of the facial maculations and the honey-yellow color of the legs and antennal scape, which distinguish it especially from Ceratina (Ceratinula) manni Cockerell, 1912, the most similar species in terms of facial maculation patterns. The geographic records of C. manni, here interpreted as endemic to the semiarid Caatinga region in northeastern Brazil, are presented, with new records for the Brazilian states of Piauí, Ceará and Bahia. A morphological description of both species is provided, including a comparison with the type specimen of C. manni from the state of Paraíba (Guarabira, formerly named Independencia). An identification key is provided for the described species of Ceratina (Ceratinula) recorded for Brazil according to Moure's Catalogue of Neotropical Bees.

Spatial Vision and Visually Guided Behavior in Apidae.

The family Apidae, which is amongst the largest bee families, are important pollinators globally and have been well studied for their visual adaptations and visually guided behaviors. This review is a synthesis of what is known about their eyes and visual capabilities. There are many species-specific differences, however, the relationship between body size, eye size, resolution, and sensitivity shows common patterns. Salient differences between castes and sexes are evident in important visually guided behaviors such as nest defense and mate search. We highlight that Apis mellifera and Bombus terrestris are popular bee models employed in the majority of studies that have contributed immensely to our understanding vision in bees. However, other species, specifically the tropical and many non-social Apidae, merit further investigation for a better understanding of the influence of ecological conditions on the evolution of bee vision.

A new species of the carpenter bee genus Xylocopa from the Sarawat Mountains in southwestern Saudi Arabia (Hymenoptera, Apidae).

A new species of the carpenter bee genus Xylocopa Latreille (Xylocopinae: Xylocopini) is described and figured from two localities in southern Saudi Arabia. Xylocopa (Koptortosoma) sarawatica Engel, sp. n. is a relatively small species similar to the widespread X. pubescens Spinola, but differs in the extent of maculation in males, setal coloration of both sexes, and male terminalia. A revised key to the species of Xylocopa in Saudi Arabia is provided.

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.

Systematics and biology of Xylocopa subgenus Schonnherria (Hymenoptera, Apidae) in Argentina.

Biological information on the species of the large carpenter bee Xylocopa subgenus Schonnherria occurring in Argentina is revised. Based on the appraisal of museum specimens, the study of type material, and field surveys conducted across 15 provinces between 2007 and 2011, the following seven species are recognized for the country: Xylocopa bambusae Schrottky, Xylocopa chrysopoda Schrottky, Xylocopa macrops Lepeletier de Saint Fargeau, Xylocopa simillima Smith Xylocopa splendidula Lepeletier de Saint Fargeau, Xylocopa pulchra Smith, and Xylocopa viridis Smith. Previous literature records of Xylocopa dimidiata Latreille, Xylocopa subcyanea Pérez, and Xylocopa varians Smith for the province of Misiones appear to have been misidentified specimens, although the presence of these species in Argentina cannot be entirely ruled out given the proximity of this province to Brazil and Paraguay where they occur; Xylocopa boops Maidl was described from a male specimen with unusually enlarged eyes and is newly synonymized under Xylocopa macrops. Males and females of all species are diagnosed, described, and figured, including details of the male genitalia. Taxonomic comments, data on the geographical distribution and nesting substrates, and identification keys to all Argentinean species of Schonnherria are provided. The nesting biologies of Xylocopa splendidula and Xylocopa viridis are documented.

Density and Distribution of Xylocopa Nests (Hymenoptera: Apidae) in Caatinga Areas in the Surroundings of Passion Fruit Crops.

Due to their importance as pollinators of many plant species, this study aimed to know the nest density, spatial distribution, and nesting substrates used by Xylocopa species in the Caatinga, a xerophilous vegetation of Northeastern Brazil. Three areas of Caatinga in the surroundings of passion fruit crops were sampled. The bee species found in these areas were Xylocopa grisescens Lepeletier and Xylocopa frontalis (Olivier). All nests were in Commiphora leptophloeos (Burseraceae) trees (n = 113). Phytosociological analysis showed that this tree species presented the highest absolute density (212.5 individuals/ha) and index of importance value (52.7). The distribution pattern of the C. leptophloeos was aggregated. The nests were located in dead and dried branches with an average diameter of 5.3 ± 2.0 cm (n = 43). The mean number of nests/tree was 3.1 ± 2.8 (n = 113). The less disturbed area showed 6.7 nests/ha and 4.2 nests/tree. In the disturbed areas, 0.9 nests/ha and 2.4 to 2.7 nests/tree were observed. The availability of substrate for nesting in the studied areas and its importance as a limiting factor for nesting are discussed.

As abelhas do gênero Xylocopa Latreille (Xylocopini, Apidae) do Estado de São Paulo, Brasil

This study contributes to the knowledge about the diversity of bees belonging to the genus Xylocopa Latreille, 1802 of the São Paulo State through a compilation of taxonomic and biological information. Identification keys are presented for the four subgenera (Dasyxylocopa Hurd & Moure, 1963; Neoxylocopa Michener, 1954; Schonnherria Lepeletier, 1841 and Stenoxylocopa Hurd & Moure, 1960) and for the 22 species recorded for the state, beyond the available data on its biology, plants visited and geographic occurrence.

Este estudo contribui para o conhecimento da diversidade das abelhas pertencentes ao gênero Xylocopa Latreille, 1802 do Estado de São Paulo através de uma compilação de informações taxonômicas e biológicas. São apresentadas chaves de identificação para os quatro subgêneros (Dasyxylocopa Hurd & Moure, 1963; Neoxylocopa Michener, 1954; Schonnherria Lepeletier, 1841 e Stenoxylocopa Hurd & Moure, 1960) e para as 22 espécies registradas para o Estado, além dos dados existentes sobre sua biologia, plantas visitadas e ocorrência geográfica.

DEL MARACUYÁ DEL GÉNERO Xylocopa(HYMENOPTERA: APIDAE, XYLOCOPINI) EN COLOMBIA / Biological and Taxonomic Notes on Maracuyá Bees of the Genus Xylocopa(Hymenoptera: Apidae, Xylocopini) in Colombia

Presentamos información sobre los hábitos de nidificación de la abeja carpintera Xylocopa (Neoxylocopa) lachnea en la cordillera Oriental de Colombia. También presentamos comentarios sobre el estado actual del conocimiento del género Xylocopa en Colombia y guías para la identificación de los subgéneros y especies más comunes en el país.

We provide information on the nesting habitats of the carpenter bee Xylocopa (Neoxylocopa) lachnea from the cordillera Oriental of Colombia. We also provide an overview of the genus Xylocopa in Colombia as well as identification keys to the subgenera and most common species in the country.

Visitantes florais do maracujá-amarelo (Passiflora edulis f. flavicarpa Deg. Passifloraceae) em áreas de cultivo com diferentes proximidades a fragmentos florestais na região Norte Fluminense, RJ / Yellow passion fruit (Passiflora edulis f. flavicarpa Deg. Passifloraceae) floral visitors in cultivated areas within different distances from forest remnants in north Rio de Janeiro state

Este trabalho teve como objetivos estudar a biologia floral e identificar os principais polinizadores do maracujá-amarelo em áreas de cultivo com diferentes proximidades a fragmentos florestais no norte do estado do Rio de Janeiro. A floração do maracujá-amarelo teve duração de nove meses, no período de setembro a maio. As flores iniciavam a antese às 12:00 h e abriam-se ao longo do dia até às 16:30 h. O processo de curvatura dos estiletes ocorreu ao longo da antese e 72,4 por cento das flores curvaram seus estiletes. A produção de néctar deu-se continuamente, atingindo 18μl/flor/hora e a concentração de solutos totais variou entre 38 e 42 por cento. Xylocopa frontalis e Xylocopa ordinaria foram os principais polinizadores do maracujá-amarelo pela freqüência de visitas, comportamento intrafloral e porte corporal. Estas espécies de abelhas, além de Apis mellifera, estiveram presentes em todas as áreas de cultivo. A maior riqueza de visitantes polinizadores do maracujá-amarelo foi observada em áreas de cultivo próximas a fragmentos florestais, fato relacionado à presença de certos grupos de abelhas nativas, como Centridini e Euglossina (Apidae) que dependem de áreas florestais para nidificação e alimentação. A proximidade a fragmentos florestais também é importante para o fornecimento de recursos alimentares e de nidificação ao longo do ano para a manutenção de populações de Xylocopa.

This work aimed to identify the main pollinators and study the floral biology of the yellow passion fruit cultivated in areas within different distances from forest remnants in north Rio de Janeiro state. The yellow passion fruit flowering lasted nine months, from September to March. Anthesis started at 12:00 h and the opening process lasted until 16:30 h. The styles bent down during the anthesis and 72.4 percent of the flowers had its styles curved. Nectar was produced continuously, reaching 18μl/flower/hour, and the total solute concentration varied between 38 and 42 percent. Xylocopa frontalis and Xylocopa ordinaria were the most effective yellow passion fruit pollinators because of their visit frequency, intrafloral behavior and body size. These bee species, besides Apis mellifera, were found in all the cultivated areas studied. The highest richness of pollinators was observed in cultivated areas closest to forest remnants. This fact is related to the presence of native bee groups, like Centridini and Euglossina bees (Apidae), which depend on forest areas for nesting and foraging. The forest remnant proximity is also important to provide the nesting and food resources needed by the Xylocopa population during the year.