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.

While the presence of secondary compounds in floral nectar has received considerable attention, much less is known about the ecological significance and evolutionary origin of secondary ‘toxic’ compounds in pollen. It is unclear whether the presence of these compounds in pollen is non‐adaptive and due to physiological ‘spillover’ from other floral tissues, or whether these compounds serve an adaptive function related to plant–pollinator interactions, such as protection of pollen against pollen thieves. Combining an experimental approach with phylogenetic comparative methods, and using western Palaearctic Boraginaceae as a model system, we investigate how pollen secondary metabolites influence, and are influenced by, relationships with bees, the main functional group of pollen‐foraging pollinators. We found a significant relationship between the levels of secondary compounds in the corollas and those in the pollen in the investigated species of Boraginaceae, suggesting that baseline levels of pollen secondary compounds may partly be due to spillover from floral tissues. At realistic levels, pollen secondary compounds showed significant detrimental effects on bee pre‐imaginal development, in agreement with previous egg‐transfer experiments showing that in some cases Boraginaceae pollen did not support pre‐imaginal development in bees not specialized on these plants. We also show that phylogenetically independent Boraginaceae taxa rewarding pollinators with pollen in addition to nectar exhibit significantly lower levels of toxic compounds in the pollen than taxa where the main reward is postulated to be nectar. Lastly, in contrast to our predictions, there was no positive association between toxin levels in the pollen of a given plant taxon and the number of bee species specialized on this taxon. We integrate all these findings and formulate an evolutionary scenario to account for the presence of toxic compounds in the pollen of Boraginaceae. We suggest that baseline levels of toxic compounds may be found in pollen due to spillover from other floral tissues and not primarily because of bee–flower interactions. Since pollen toxins can have detrimental effects on bees, we propose that selection acts to lower pollen toxin levels in plants where pollen, in addition to nectar, serves as a reward to bees. A free Plain Language Summary can be found within the Supporting Information of this article.

Abstract. Outside of the principal distribution and major diversification of Macrocarpaea in the Andes, smaller groups of species are found in the Greater Antilles of the Caribbean, Mesoamerica, the Guayana Highlands, and montane Atlantic forests of Brazil. Here, a complete revision of the genus in the latter region is presented recognizing eight species that correspond to the entirety of Macrocarpaea sect. Tabacifoliae:nov., and M. rubra Malme. These species occur primarily in humid coastal montane rainforests (Mata Atlântica), and two species also occur in campos rupestre montane savannas.Keywords: Macrocarpaea, Gentianaceae, Helieae, Brazil, Mata AtlânticaThe following herbaria are acknowledged for the loan of material, photocopies of specimens, data on their collections, and/or for hospitality extended during visits* by JRG to examine material of Macrocarpaea: AAU,

herein we present information on the nesting behavior of Ochreriades fasciatus (Friese) found occupying beetle galleries in dead trunks and branches of certain trees and shrubs in israel. We also describe the pre-and postdefecating larvae thereby making known the mature larva for this uncommon Old World genus. Females of O. fasciatus build linear nests in existing burrows in dead wood; depending on the length of the burrow, 1-5 cells are placed in one nest. The cell partitions are made of hardened mud, while the nest plug consists of pebbles fixed together with mud. Ochreriades fasciatus is oligolectic on Lamiaceae and probably strongly associated with the two related genera Ballota and Moluccella. it is hoped that information concerning its nesting biology, host-plant relationships, as well as larval development and anatomy will eventually prove valuable in determining the phylogenetic position of this genus relative to other megachiline bees.1 division of invertebrate zoology, American Museum of Natural history. 2 steinhardt Museum of Natural history and National research center, Faculty of Life sciences, tel Aviv university, israel. 3 institute of Biology, university of Neuchatel, switzerland. 4 department of entomology, cornell university.

Hofferia and Stenoheriades are closely related, species-poor genera of the osmiine bees (Megachilidae). Analysis of female pollen loads and field observations indicate that species of both genera have a strong affinity to Asteraceae as pollen hosts. Both genera use insect burrows in dead wood as nesting site, and Hofferia schmiedeknechti was found to build cell walls and nest plug with resin partly mixed with small pebbles. The taxonomic revision of the Palaearctic Hofferia and Stenoheriades species revealed the existence of a still undescribed species in the Levant, Stenoheriades levantica spec. nov.. Stenoheriades hofferi (Tkalců, 1984) is synonymized with S. coelostoma (Benoist, 1935), which is distinct from S. asiatica (Friese, 1921), and Heriades integra Benoist, 1934, formerly considered a Stenoheriades species, is synonymized with Osmia (Hoplosmia) scutellaris Morawitz, 1868. Keys for the delimitation of Hofferia and Stenoheriades from the other Palaearctic osmiine bee genera and for the identification of the Palaearctic species are given.