Elevated rates of dietary generalization in eusocial lineages of the secondarily herbivorous bees.

BACKGROUND: Within the Hymenoptera, bees are notable for their relationship with flowering plants, being almost entirely dependent on plant pollen and nectar. Though functionally herbivorous, as a result of their role as pollinators, bees have received comparatively little attention as models for insect herbivory. Bees often display dietary specialization, but quantitative comparison against other herbivorous insects has not previously been conducted. RESULTS: In the most comprehensive analysis to date for 860 bee species, dietary specialization amounted to 50.1% of studied species collecting pollen from between 1 and 2 botanical families with a relatively long tail of dietary generalists, with 11.1% of species collecting from more than 10 botanical families. This distribution deviated from the truncated Pareto distribution of dietary breadth seen in other herbivorous insect lineages. However, this deviation was predominantly due to eusocial bee lineages, which show a range of dietary breadths that conformed to a normal distribution, while solitary bees show a typical truncated distribution not strongly different from other herbivorous insects. We hypothesize that the relatively low level of dietary specialization in bees as a whole reflects the relaxation of the constraints typically observed in herbivorous insects with a comparatively reduced importance of plant chemistry and comparatively increased importance of phenology and foraging efficiency. The long flight periods of eusocial bees that are necessary to allow overlapping generations both allows and necessitates the use of multiple flowering resources, whereas solitary bees with short flight periods have more limited access to varied resources within a constrained activity period. CONCLUSIONS: Collectively, solitary bees show slightly lower specialization compared to other herbivorous insects, possibly due to their balanced relationship with plants, rather than direct antagonism such as seen in the direct consumption of plant tissues. An additional factor may be the mediocre diversity of bees at low latitudes combined with low levels of dietary specialization, whereas these areas typically display a high rate of specialization by herbivorous insects in general. Though the most important factors structuring dietary specialization in bees appear to differ from many other herbivorous insects, solitary bees show a surprisingly similar overall pattern of dietary specialization.

Working Together and Being Physically Active Are Not Enough to Advise Uniformly and Adequately Low Back Pain Patients: A Cross-Sectional Study.

The profession of the health-care providers (HCPs) influences their recommendations to the patients. Conversely, interdisciplinarity seeks to challenge such differences, so that the patient receives one single and consistent therapeutic message. Some studies also suggest associations between HCPs life habits and recommendations. Our hypotheses were (1) that despite interdisciplinary work, the profession remains a predictor of recommendations and (2) that HCPs who are more physically active recommend more activity. Three clinical vignettes were presented to a group of experts of low back pain (LBP) (guidelines), and 20 physicians, 22 physiotherapists, and 23 nurses to assess how they evaluate the symptoms and pathologies of LBP patients and how much work and physical activity they recommend. Physical activity was assessed with accelerometers and questionnaires. Some interprofessional differences remained present within an interdisciplinary team. The nurses were more restrictive and further away from the guidelines. The physicians were the most in line with them. The physiotherapists recommend as much physical activity, but less work activity than the physicians. The level of physical activity of the HCPs is not associated with their recommendations. To ensure a clear and unique message, educational actions may be undertaken to promote the biopsychosocial model and clarify the guidelines.

Phylogeny, new generic-level classification, and historical biogeography of the Eucera complex (Hymenoptera: Apidae).

The longhorn bee tribe Eucerini (Hymenoptera: Apidae) is a diverse, widely distributed group of solitary bees that includes important pollinators of both wild and agricultural plants. About half of the species in the tribe are currently assigned to the genus Eucera and to a few other related genera. In this large genus complex, comprising ca. 390 species, the boundaries between genera remain ambiguous due to morphological intergradation among taxa. Using ca. 6700 aligned nucleotide sites from six gene fragments, 120 morphological characters, and more than 100 taxa, we present the first comprehensive molecular, morphological, and combined phylogenetic analyses of the 'Eucera complex'. The revised generic classification that we propose is congruent with our phylogeny and maximizes both generic stability and ease of identification. Under this new classification most generic names are synonymized under an expanded genus Eucera. Thus, Tetralonia, Peponapis, Xenoglossa, Cemolobus, and Syntrichalonia are reduced to subgeneric rank within Eucera, and Synhalonia is retained as a subgenus of Eucera. Xenoglossodes is reestablished as a valid subgenus of Eucera while Tetraloniella is synonymized with Tetralonia and Cubitalia with Eucera. In contrast, we suggest that the venusta-group of species, currently placed in the subgenus Synhalonia, should be recognized as a new genus. Our results demonstrate the need to evaluate convergent loss or gain of important diagnostic traits to minimize the use of potentially homoplasious characters when establishing classifications. Lastly, we show that the Eucera complex originated in the Nearctic region in the late Oligocene, and dispersed twice into the Old World. The first dispersal event likely occurred 24.2-16.6 mya at a base of a clade of summer-active bees restricted to warm region of the Old World, and the second 13.9-12.3 mya at the base of a clade of spring-active bees found in cooler regions of the Holarctic. Our results further highlight the role of Beringia as a climate-regulated corridor for bees.

Comprehensive phylogeny, biogeography and new classification of the diverse bee tribe Megachilini: Can we use DNA barcodes in phylogenies of large genera?

Classification and evolutionary studies of particularly speciose clades pose important challenges, as phylogenetic analyses typically sample a small proportion of the existing diversity. We examine here one of the largest bee genera, the genus Megachile - the dauber and leafcutting bees. Besides presenting a phylogeny based on five nuclear genes (5480 aligned nucleotide positions), we attempt to use the phylogenetic signal of mitochondrial DNA barcodes, which are rapidly accumulating and already include a substantial proportion of the known species diversity in the genus. We used barcodes in two ways: first, to identify particularly divergent lineages and thus to guide taxon sampling in our nuclear phylogeny; second, to augment taxon sampling by combining nuclear markers (as backbone for ancient divergences) with DNA barcodes. Our results indicate that DNA barcodes bear phylogenetic signal limited to very recent divergences (3-4 my before present). Sampling within clades of very closely related species may be augmented using this technique, but our results also suggest statistically supported, but incongruent placements of some taxa. However, the addition of one single nuclear gene (LW-rhodopsin) to the DNA barcode data was enough to recover meaningful placement with high clade support values for nodes up to 15 million years old. We discuss different proposals for the generic classification of the tribe Megachilini. Finding a classification that is both in agreement with our phylogenetic hypotheses and practical in terms of diagnosability is particularly challenging as our analyses recover several well-supported clades that include morphologically heterogeneous lineages. We favour a classification that recognizes seven morphologically well-delimited genera in Megachilini: Coelioxys, Gronoceras, Heriadopsis, Matangapis, Megachile, Noteriades and Radoszkowskiana. Our results also lead to the following classification changes: the groups known as Dinavis, Neglectella, Eurymella and Phaenosarus are reestablished as valid subgenera of the genus Megachile, while the subgenus Alocanthedon is placed in synonymy with M. (Callomegachile), the subgenera Parachalicodoma and Largella with M. (Pseudomegachile), Anodonteutricharaea with M. (Paracella), Platysta with M. (Eurymella), and Grosapis and Eumegachile with M. (Megachile) (new synonymies). In addition, we use maximum likelihood reconstructions of ancestral geographic ranges to infer the origin of the tribe and reconstruct the main dispersal routes explaining the current, cosmopolitan distribution of this genus.