Large Bees Research Articles

The world’s largest bee vanished decades ago. Now, scientists have spotted it again

The world’s largest bee vanished decades ago. Now, scientists have spotted it again

Characterization of mitochondrial genomes of three Andrena bees (Apoidea: Andrenidae) and insights into the phylogenetics.

Andrena is a large bee genus of >1500 species, which includes many important pollinators of agricultural systems. In this study, we present three mitochondrial genomes (mitogenomes) of Andrena species, which are the pollinators of Camellia oleifera. Compared with putative ancestral gene arrangement of insects, the three mitogenomes present identical gene rearrangement events, including local inversion (trnR) and gene shuffling (trnQ/trnM, trnK/trnD, and trnW/trnC-trnY). Most PCGs initiate with standard ATN codon and share the stop codon of TAA or TAG, whereas truncated stop codon T was detected in the atp6 gene of A. chekiangensis. Furthermore, the nad4 gene end with a single T in all three Andrena species. All tRNAs could be folded into clover-leaf secondary structure except for trnS1, with the dihydrouracil (DHU) arm forming a simple loop. Phylogenetic analysis is performed on 17 Andrena mitogenomes. Maximum likelihood and Bayesian methods generate identical topology, in which A. hunanensis and A. striata form a group and are close to A. camellia. Although A. chekiangensis is also difficult to be distinguished from A. camellia by morphological methods, A. chekiangensis and A. haemorrhoa form a clade and are grouped with the other taxa of the genus Andrena.

THE FIRST DOCUMENTED RECORD OF AEROGLYPHUS PEREGRINANS (BERLESE, 1892) (ACARIDIA, AEROGLYPHIDAE) IN THE HIVES OF HONEY BEES (APIS MELLIFERA) IN UKRAINE

Studying of mite communities in hives of Apis mellifera Linnaeus, 1758 in Zhytomyr region revealed Aeroglyphus peregrinans (Berlese, 1892) mites. Feeding stages of this species most frequently disperse on large carpenter bees, rarely on bumble bees, or honey bees. This is the first documented finding of A . peregrinans in beehives in Ukraine [2]. The record of A. peregrinans most close to Zhytomyr region was from the nature reserve “Mys Martian”, Crimea. There this species were observed on Xylocopa violacea (Linnaeus, 1758) . The A. peregrinans is a subdominant (by Shitikov’s scale of dominance structure) in the mite complex of acaridia mites of honeybee hives in Zhytomyr region. Most of the specimens are recorded at the north of Zhytomyr region in Ovruch town. It is possible that the mite species can be introduced from the southern regions with bee packages and queen bees. The A. peregrinans mites were able to inhabit bee hives due to the presence of abundant feeding substrate (especially ambrosia, litter and dead bees) and the A. mellifera hives also provide relatively stable conditions (temperature, humidity). Seasonal fluctuations of their numbers in samples are analyzed. The 99 % of mites were found in spring samples, and the remaining 1 % of mites was recorded in autumn samples. This is explained by the difference in sample content; the spring samples are mostly bees which died during winter. That why most of the specimens were found in samples of dead bees. The A. peregrinans mites were absent in samples consisting mostly of ambrosia and litter (honey crystals, wax crumbs) from the hive bottom. According to the published data, previous records and our research dead bees are the main feeding substrate of the studied species in honey bee hives.

Honey Norisoprenoids Attract Bumble Bee, Bombus terrestris, in New Zealand Mountain Beech Forests.

Three varieties of honey of different dominant floral origin were found to attract social Hymenoptera, including the large earth bumble bee, Bombus terrestris, in a New Zealand mountain beech forest. This study was undertaken to identify volatile organic compounds that induce the attraction of bumble bees to honeybee ( Apis mellifera) honey. We analyzed the chemical composition of the volatile organic compounds produced in three distinct varieties of honey (i.e., manuka, honeydew, and clover honey). The composition of the chemical profile of the three honey varieties differed in the quality and in the ratio of compounds in the headspace. o-Methoxyacetophenone was the main compound in the headspace of all three honey varieties. Among the 40 compounds identified in the headspace in the three varieties, only seven shared compounds (i.e., benzaldehyde, benzyl alcohol, phenylacetaldehyde, 2-phenylethanol, isophorone, 4-oxoisophorone, and o-methoxyacetophenone) were present in the headspace of the three honey varieties. The relative attractiveness of various blends of the seven common compounds found in the three honey varieties was tested for the attraction to bumble bees in a mountain beech forest. A binary blend of isophorone and 4-oxoisophorone at a ratio of 90:10 was the most attractive blend for both bumble bee workers and queens. A small number of honey bee workers were also attracted to the former binary blend. Our study represents the first identification of a honey-derived attractant for bumble bees and honey bees. The potential application of our finding for monitoring of bumble bees or to enhance crop pollination and help to tackle the current concern of a global pollination crisis is discussed.

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.

Engenieering Technology in Plastic Biodegradation by Large Bee Moth Larvae Depends on the Type of Polyethylene

The objective of this research was to evaluate the processes of biodegradation of different types of polyethylene by G. mellonella larvae. The determination of the types of polyethylene samples was carried out by IR Fourier spectrometry. The structure of solid household waste includes polyethylene of different types. When assessing the degree of biodegradation, it was found that holes in the polyethylene samples of different sizes formed 5.3±2.4 - 28.7±9.4 units/day and 54.8±12.6 - 1867.8±38.6 mm2/day, and the mass of polyethylene samples, depending on the type, decreased on average by 1.5±0.5 - 51.0±6.5 μg/day. The obtained results of survival, mobility, weight gain and melanization indicate the absence of negative health effects on larvae when eating polyethylene.

Flowers with poricidal anthers and their complex interaction networks—Disentangling legitimate pollinators and illegitimate visitors

Abstract In flowers with poricidal anthers, pollen is not freely accessible and legitimate access is restricted to bees capable of vibrating the anthers. Despite the protection of pollen provided by poricidal anthers, numerous illegitimate, non‐buzz‐pollinating flower visitors rob pollen. We aimed to quantify the influence of functional groups of floral visitors and illegitimate interactions on the network structure to disentangle the flower visitor network into its mutualistic and antagonistic components. We delimited three functional groups of bees based on their pollen collection behaviour in poricidal flowers: large bees that vibrate entire flowers in a single buzzing position (flower buzzing), bees vibrating single anthers in different positions (anther buzzing) and non‐vibrating flower‐damaging or gleaning bees (non‐buzzing). Moreover, we characterized legitimate and illegitimate interactions of co‐occurring and co‐flowering plants and their flower visitors based on the stigma contact during a visit. Since we independently assessed the type of interaction with bee–plant species combinations, we were able to include the behavioural variations of each bee species across different flowers. The networks were modular, with stronger interactions within subsets of species than among the subsets. All modules included a combination of flower‐, anther‐ and non‐buzzing bees, and mutualistic and antagonistic networks were intermingled. Seven bee species shifted their roles across plant species. Specialization in the subset of interactions with pollinators was higher than the overall visitation network. Flower‐buzzing bees were more specialized than anther‐buzzing and non‐buzzing bees, which used virtually all poricidal flowers similarly. Although plants with poricidal anthers shared a specialized mechanism of pollen release, their pollinators were highly dissimilar and formed compartments of interacting species. The interaction‐level approach taken in our study confers a high specificity to the pollinator network, leading to a more complex and realistic picture of mutualistic webs versus its embedded florivory, which are otherwise confounded in pooled networks across flower visitors. A plain language summary is available for this article.

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.

Salvia verticillata: Linking glandular trichomes, volatiles and pollinators

Plants have developed a plethora of signals to interact with other organisms, finally building up a sophisticate language for communication. In this context, we investigated Salvia verticillata L. (Lamiaceae), with the primary goal to link secondary metabolites and actual biotic relationships. We specifically analysed the volatile organic compounds (VOC) spontaneously emitted by leaves and flowers and determined the composition of the essential oils obtained from the aerial parts across 2015 and 2016. We merged information of chemical analyses to a micromorphological investigation on the glandular indumentum and to focal observations on the pollinator assemblage.The VOC profiles were highly variable, with the floral bouquet being the most complex. Flowers and leaves showed 37 and 20 exclusive compounds, dominated by 1,8-cineole (10.4%) and germacrene D (38.4%), respectively. Sesquiterpene hydrocarbons prevailed (83.3% leaves; 73.7% flowers) and 19 common compounds were detected.The oil profiles proved to be consistent across the two years: sesquiterpene hydrocarbons invariably dominated, with germacrene D, bicyclogermacrene and β-caryophyllene as main compounds.The whole plant epidermis is thickly covered by two types of glandular hairs: peltates and small capitates, both responsible for the synthesis of terpenes, finally resulting in the VOC emission and in the essential oil production.S. verticillata attracted mainly bees belonging to two functional groups: medium-sized and large bees, notwithstanding the small size of its flowers. At the site, Apis mellifera and different Bombus species were recorded, mainly interested in feeding on nectar. The literature survey on the isolated volatile compounds confirmed the hypotheses on the seduction strategies towards Apoidea.

How are pollination and seed dispersal modes in Cerrado related to stratification? Trends in a cerrado sensu stricto woodland in southeastern Brazil, and a comparison with Neotropical forests

A comprehensive census of a hectare of cerrado s.s. in southeastern Brazil, a small-tree and scrub woodland physiognomy, allowed the evaluation of whether pollination and dispersal modes are correlated with the stratification of the vegetation and if so, in what way. Generalist pollination, and pollination by small bees, as well as ornithophily and anemophily were more frequent in the lower layers (ground and scrub), while species pollinated by large bees and beetles are more or less equally distributed among the ground, scrub and tree layers. The three nocturnal pollination modes, phalenophily, sphingophily, and chiropterophily indicated a preference for the upper layers (tree and scrub). Zoochory predominated in the tree layer, but autochory increased towards the ground at the expense of anemochory and zoochory. We discuss possible reasons for the height distribution of pollination and seed dispersal modes and compare the situation in Cerrado with other Neotropical forests.

Nectar dynamics and reproductive biology of Passiflora actinia Hook. (Passifloraceae) in Araucaria Forest

ABSTRACT Nectar production has an important role in pollinator attraction and successful fruit production in many self-incompatible angiosperm groups. The reproductive biology of Passiflora actinia was studied here and related to nectar dynamics. Passiflora actinia presented a temporal segregation of male and female functions at the beginning of anthesis. Due to the movements of floral verticils, the anthers were positioned in a way that favors pollination two hours before the stigmas reached the same position. The nectary consisted of an epidermis with stomata and a parenchyma rich in starch, which was hydrolyzed during anthesis. The nectary organization is probably associated with the continuous production of nectar during anthesis as well as with the high mean nectar concentration. Hand pollination tests indicated that Passiflora actinia is obligately xenogamous, depending on large bees for pollination, specifically the carpenter bee Xylocopa augusti. The continuous production of nectar may increase the number of bee visits, thus favoring pollen flow.

Reduction by half: the impact on bees of 34 years of urbanization

Urban ecosystems are growing rapidly and urbanization is an important cause of the loss of biodiversity. Bees are declining in abundance worldwide, including urban areas, and this decline is alarming because of their global importance as plant pollinators. Here we examine that decline by comparing a bee assemblage sampled in the 1980s and again in 2015, in an urban area of the city of Curitiba. Both studies sampled assemblages with hand-nets every two weeks during one year of study. Bee species richness has declined by 45% (112 species then, 63 today). Two species that have disappeared, Gaesischia fulgurans (Holmberg, 1903) and Thectochlora basiatra (Strand, 1910), have also disappeared elsewhere in the city. Also, relative abundances of species have changed, notably with the increase of social bees. Large bees that nest in cavities have also increased relative to small bees that nest in the ground. These findings are similar with previous reports indicating the sensibility of bees to urbanization. The increase in paved areas, in urban population and in exotic plants are all probably responsible for the sharp decline in bee diversity and abundance.

Morphological Complexity as a Floral Signal: From Perception by Insect Pollinators to Co-Evolutionary Implications.

Morphologically complex flowers are characterized by bilateral symmetry, tube-like shapes, deep corolla tubes, fused petals, and/or poricidal anthers, all of which constrain the access of insect visitors to floral nectar and pollen rewards. Only a subset of potential pollinators, mainly large bees, learn to successfully forage on such flowers. Thus, complexity may comprise a morphological filter that restricts the range of visitors and thereby increases food intake for successful foragers. Such pollinator specialization, in turn, promotes flower constancy and reduces cross-species pollen transfer, providing fitness benefits to plants with complex flowers. Since visual signals associated with floral morphological complexity are generally honest (i.e., indicate food rewards), pollinators need to perceive and process them. Physiological studies show that bees detect distant flowers through long-wavelength sensitive photoreceptors. Bees effectively perceive complex shapes and learn the positions of contours based on their spatial frequencies. Complex flowers require long handling times by naive visitors, and become highly profitable only for experienced foragers. To explore possible pathways towards the evolution of floral complexity, we discuss cognitive mechanisms that potentially allow insects to persist on complex flowers despite low initial foraging gains, suggest experiments to test these mechanisms, and speculate on their adaptive value.

New records and diagnostic notes on large carpenter bees (Hymenoptera: Apidae: genus Xylocopa Latreille), from the Amazon River basin of South America

New records and diagnostic notes on large carpenter bees (Hymenoptera: Apidae: genus Xylocopa Latreille), from the Amazon River basin of South America

Reproduction, pollination and seed predation of Senna multijuga (Fabaceae) in two protected areas in the Brazilian Atlantic forest

One important subject is to determine the effectiveness of conservation areas, where different management categories are being applied, to maintain effective sexual reproduction in plants and their interactions with animal groups. To evaluate this issue, we compared the phenology, reproductive success, pollination and pre-dispersal seed predation of the legume tree Senna multijuga in two differently managed protected areas in Southeastern Brazil: the Itatiaia National Park and the Environmental Protection Area of Serrinha do Alambari, from December 2007 to December 2008. Vegetative and reproductive phenodinamycs were registered monthly in 80 individuals; other evaluations included 104 observation hours for pollination (March-May 2008) in 51 inflorescences; besides, fruit counts, fecundity and seed predation. Sexual reproduction of S. multijuga depends on the transfer of pollen by large bees (Bombus, Centris, Epicharis and Xylocopa), as the species is self-incompatible. Bruchidae species of the genus Acanthoscelides and Sennius predate seeds. Vegetative and reproductive phenodynamics differed among sites. Our results indicated that ecological interactions were lower at the protected area, but the reproductive processes in S. multijuga were not ruptured or critically degraded. This reinforces the idea that landscape areas with intermediate levels of protection, such as environmental protection areas, are suitable as buffer zones, and thus, relevant to the conservation of ecological processes when associated with more strictly protected areas.

Pollination of Granadilla (Passiflora ligularis) Benefits From Large Wild Insects.

The contribution of wild pollinators to food production has recently been assessed for many crops, although it remains unclear for several tropical crops. Granadilla (Passiflora ligularis Juss), a crop native to the tropical Andes, is one such crop where a gap exists regarding comprehensive knowledge about its pollination system. In a field experiment in the Colombian Andes, we 1) describe flower visitors in terms of visit quantity (visitation rate) and quality (touches of flower-reproductive structures), 2) assess the pollination system by comparing fruit set and fruit weight per flower in three pollination treatments: pollinator exclusion, open pollination, and supplementary pollination, and 3) evaluate pollination deficits (difference between open and supplementary pollination) in relation to pollinator density. We observed 12 bee species visiting granadilla flowers, with Apis mellifera Linnaeus being the most frequent species. However, large bees such as Xylocopa lachnea Moure and Epicharis rustica Olivier touched stigmata and anthers more often. Fruit set and fruit weight per flower were significantly lower in the pollinator exclusion treatment compared to open and supplementary pollination, while the latter treatments showed nonsignificant differences. Pollination deficit significantly decreased with the increasing density of large bees and wasps. Our results illustrate the high dependency of granadilla on wild pollinating insects and highlight the crucial role of large insects to granadilla production. This stresses the need to maintain or increase the density of large pollinators in granadilla production areas, which in turn will necessitate better knowledge on their ecological requirements to inform landscape planning and population-management programs.

On the development of a predictive functional trait approach for studying terrestrial arthropods.

The characterization of ecological communities with functional traits allows to consider simultaneously the ability of a species to survive and reproduce in an environment, its interactions with other species and its effects on the ecosystem. Functional traits have been studied mainly by plant ecologists, but are increasingly common in the study of other taxa including arthropods. Arthropods represent a group for which a functional trait approach could be highly profitable because of their high diversity, abundance, ubiquity and role in many important ecological processes. This review synthesizes two decades of functional trait research on terrestrial arthropods. We show that while the approach has gained popularity, particularly in the last decade, the absence of clearly postulated hypotheses is a recurrent problem limiting generalization. Furthermore, studied traits are often poorly related to studied functions. To address these problems, we propose a step-by-step protocol to postulate clear hypotheses prior to trait selection and emphasize the need for a common set of more generalizable traits in future studies. Extending the functional trait approach to arthropods opens the door to improving our understanding of interspecific interactions and potential links between response and effect traits. We present the concept of trait-matching with several examples of arthropod traits known to be effective predictors of consumer-resource interactions. The development of a successful functional trait approach for terrestrial arthropods will necessitate an understanding of relevant traits, standardized measurement protocols and open access databases to share this information. Such progress will provide ecologists with a new set of tools to answer broad questions in several fields including the study of community assembly, ecological networks and multitrophic functionality.

Floral Biology of the federally threatenedApios priceana(Fabaceae)

Apios priceana B. L. Rob. is federally threatened and little is known about its pollination biology. At the Redstone Arsenal population, Alabama, we studied its breeding system, determined major floral visitors and their pollination effectiveness, and explored pollen limitation of fruit and seed production. Fruit initiation was low (3.9%) for cross-pollinated flowers but only marginally greater than for self-pollinated or nonpollinated flowers (none initiated a fruit). Most floral visits (97%) were by bees with 43% of visits by large bees (> 1.5 cm in length) and 51% by medium bees (1–1.5 cm in length). Keel petals of A. priceana flowers enclose the style and stamens: flowers must be “tripped” for pollination to occur. Large and medium bees were equally effective in tripping flowers, whereas small bees (< 1 cm in length) did not trip flowers. Success of large and medium bee species (several Bombus species and Megachile sculpturalis Smith) in initiating legumes after a single floral visit ranged from 17–35% but did not differ significantly among species. Pollen supplementation showed legume production was pollen-limited: 24% of supplemented flowers produced fruits versus 6% of nonsupplemented flowers. Seed counts revealed a marginally nonsignificant trend for more seeds in legumes from pollen-supplemented flowers. We conclude that this rare plant species is dependent on medium and large bees for pollination, and that reproduction is partially pollen-limited. Conservation efforts should include measures to protect bee pollinators of this species to ensure that managed populations of this rare plant continue to reproduce sexually.

Atmospheric nitrogen deposition in terrestrial ecosystems: Its impact on plant communities and consequences across trophic levels

Abstract The global nitrogen cycle has been greatly perturbed by human activities resulting in elevated nitrogen deposition in many parts of the world. The threat nitrogen deposition poses to ecosystem function and biodiversity is increasingly recognised. In terrestrial systems, impacts on the plant community are mainly through eutrophication and soil acidification. Interactions with secondary environmental drivers such as extreme weather and disease are also key mechanisms. Impacts on consumers can be caused by changes in the quality or quantity of food as a result of changes in food plant chemistry or species composition, changes in vegetation structure leading to a change in the availability of prey species, nesting sites or cooled microclimates or changes in the phenology of plants leading to causing phenological asynchrony. Primary consumers have received considerably less research attention than plants but negative impacts have been observed for both folivorous insects and pollinators. Mammal herbivores have received little research attention. New analysis of changes in plant traits along a gradient of nitrogen deposition in the UK shows that plants pollinated by large bees were negatively associated with N deposition whilst low pH was associated with lower nectar production, reduced occurrence of plants pollinated by long‐tongued insects and a reduction in plants with larger floral units. Very few studies have investigated the effects on secondary consumers, but those that have suggest that there are likely to be negative impacts. This review identifies considerable knowledge gaps in the impacts of N deposition on higher tropic levels and highlights that for many groups, knowledge of N deposition impacts is patchy at best. Evidence that has been collected suggests that there are likely to be impacts on primary and secondary consumers making this a priority area for investigation.

Fragmentation of nest and foraging habitat affects time budgets of solitary bees, their fitness and pollination services, depending on traits: Results from an individual-based model.

Solitary bees are important but declining wild pollinators. During daily foraging in agricultural landscapes, they encounter a mosaic of patches with nest and foraging habitat and unsuitable matrix. It is insufficiently clear how spatial allocation of nesting and foraging resources and foraging traits of bees affect their daily foraging performance. We investigated potential brood cell construction (as proxy of fitness), number of visited flowers, foraging habitat visitation and foraging distance (pollination proxies) with the model SOLBEE (simulating pollen transport by solitary bees, tested and validated in an earlier study), for landscapes varying in landscape fragmentation and spatial allocation of nesting and foraging resources. Simulated bees varied in body size and nesting preference. We aimed to understand effects of landscape fragmentation and bee traits on bee fitness and the pollination services bees provide, as well as interactions between them, and the general consequences it has to our understanding of the system. This broad scope gives multiple key results. 1) Body size determines fitness more than landscape fragmentation, with large bees building fewer brood cells. High pollen requirements for large bees and the related high time budgets for visiting many flowers may not compensate for faster flight speeds and short handling times on flowers, giving them overall a disadvantage compared to small bees. 2) Nest preference does affect distribution of bees over the landscape, with cavity-nesting bees being restricted to nesting along field edges, which inevitably leads to performance reductions. Fragmentation mitigates this for cavity-nesting bees through increased edge habitat. 3) Landscape fragmentation alone had a relatively small effect on all responses. Instead, the local ratio of nest to foraging habitat affected bee fitness positively through reduced local competition. The spatial coverage of pollination increases steeply in response to this ratio for all bee sizes. The nest to foraging habitat ratio, a strong habitat proxy incorporating fragmentation could be a promising and practical measure for comparing landscape suitability for pollinators. 4) The number of flower visits was hardly affected by resource allocation, but predominantly by bee size. 5) In landscapes with the highest visitation coverage, bees flew least far, suggesting that these pollination proxies are subject to a trade-off between either longer pollen transport distances or a better pollination coverage, linked to how nests are distributed over the landscape rather than being affected by bee size.