Corresponding author: Christophe J. Praz (
Academic editor: J. Neff
A new identification key is presented for the western Palearctic subgenera of the bee genus
Praz CJ (2017) Subgeneric classification and biology of the leafcutter and dauber bees (genus
The bee genus
Palearctic leafcutter and dauber bees have not been recently revised, with the exception of the central European species for which identification keys are available (e.g.,
As a first step towards a better taxonomic treatment of this important group of bees, a new key to the western Palearctic subgenera is proposed here; when needed, I delineate species groups within large subgenera. For some subgenera, I briefly comment on the species composition and highlight taxonomic problems associated with some species. For large subgenera such as
Terminology follows
The keys presented by
As mentioned above, the key covers the northern parts of the Arabian Peninsula (Saudi Arabia north of Jeddah) as well as the United Arab Emirates but not the southern part (Yemen, Oman, southern parts of Saudi Arabia). The fauna of the southern part of the Arabian Peninsula is poorly known and rather distinct from the Palearctic fauna: temperate subgenera such as
Informal “species groups” are particularly convenient for referring to groups of presumably related taxa sharing distinctive morphological features; such informal groups are not regulated by the code of zoological nomenclature and do not have to be monophyletic. Furthermore, it does not matter if the recognition of such groups renders the rest of the subgenus paraphyletic. I use species groups to facilitate the taxonomic treatment of large, diverse subgenera. Such subgenera typically appear in different couplets of the key and I find it useful to have a name to refer to these groups. Often, such groups have been given subgeneric rank in the past, for example “
The following three species descriptions were likely based on mislabeled specimens. First,
The type of
A likely syntype of
The following new synonymies are proposed based on the examination of the type material, or if the type material could not be obtained or examined, on the original descriptions. Rationale and details on each of these synonymies are given in Suppl. material
The subgeneric placement of
Female mandible of
For the separation of the different leafcutter subgenera of Africa,
Female mandible of
Another useful character for the separation of the subgenera is the conformation of the two setae on the basal part of the claws (
Claw of hind leg of females; the white lines show the basal seta; the seta is considered elongate in
Many male
Inferior projection of male mandible.
Lastly, other useful characters to separate the subgenera of Michener’s group 1 are found on the metasomal sterna (Figs
Male metasoma, ventral view.
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2 | Mandible (Fig. |
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– | Mandible not as above: tooth 1 often not larger than other teeth; or teeth or interspaces above tooth 1 of different shapes or not becoming gradually smaller (Figs |
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3 | Mandible without cutting edges between the teeth (Figs |
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– | Mandible with cutting edges in at least one interspace (Fig. |
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4 | Large species, body length above 14 mm. Vestiture predominantly black except snow white on posterior parts of mesosoma and on |
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– | Body length variable. Vestiture different. Character combination not as above: clypeus modified or not; if modified, then mandible surface dulled by microsculpturing (Fig. |
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5 | Clypeus modified, with either a broad, vertical, shiny truncation (Fig. |
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– | Clypeus with apical margin convex (Fig. |
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6 | Clypeus with apical margin convex and produced over base of labrum, denticulate or at least with 3–4 blunt, impunctate tubercles (Fig. |
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– | Clypeus with apical margin straight or weakly convex, usually not produced over base of labrum (Figs |
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7 | Basal hair on claws of all legs comparatively long, length more than 4 times its basal width, in appearance and color similar to apical hair, although shorter (Fig. |
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– | Basal hair on claws of all legs modified to a thicken process, length at most 4 times its basal width (Fig. |
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8 | Mandible in front view (Figs |
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– | Mandible not as above, either with a complete cutting edge in third interspace (Fig. |
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9 | Scopa usually orange at least on |
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– | Scopa often white on |
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10. | Mandible robust (Fig. |
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– | Mandible less robust (Figs |
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11 | Coxa 1 without tooth or projection, although surface sometimes angulate [e.g. in |
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– | Coxa 1 with tooth or projection, projection sometimes short but well visible [in |
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12 | Large species (i.e. body length above 13 mm) with vestiture predominantly black except snow-white on posterior parts of mesosoma, on |
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– | Body length variable. Combination of characters not as described above, especially vestiture. Preoccipital carina absent laterally. Preapical carina of |
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13 | Small species (i.e. body size 7–9 mm) with mid and hind legs orange-red and front tarsi yellow-orange. Mandible with inferior projection. |
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- | Combination of characters not as described above; mostly larger species ≥ 10 mm; if body length less than 10 mm, then preapical carina of |
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14 | Preapical carina of |
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– | Preapical carina of |
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16 |
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17 | Mandible with inferior process produced posteriorly to a triangular spine resting on hypostomal area in repose (Fig. |
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– | Mandible either without inferior process; or with inferior process truncate, quadrate, not projecting posteriorly, often covered by hairs (as in Fig. |
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19 | Front coxal tooth long, at least twice as long as basal width |
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– | Front coxal tooth not particularly long, |
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21 | Preoccipital carina present laterally. Preapical carina of |
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– | Preoccipital carina absent laterally or very weak. Preapical carina of |
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22 | Mandible always without inferior projection and |
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– | Mandible with or without quadrate inferior projection, but if projection absent, then |
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This subgenus is widely distributed in the Old World (
Female clypeus and mandibles, front view.
The Palearctic species of
Very little is known on the biology of this subgenus.
In the few species present in the Palearctic, the preoccipital carina is always well developed and constitutes a good diagnostic trait.
Most species of the subgenus
Female clypeus and mandibles, front view.
Females of this subgenus are sculpturally uniform and frequently exhibit mimetic color evolution; hidden sternites of males are mostly diagnostic but these structures have only been described for few species (e.g.
The nesting biology of
Many species of
The subgenus
Female clypeus and mandibles, front view.
Most Palearctic species fall into a rather homogenous group of species referred to here as the
The nesting biology of
Female clypeus and mandibles, front view.
This subgenus is diverse in Africa, where it forms numerous, morphologically distinct species groups (
Both Arabian species of the
Little is known on the biology of
Apex of male metasoma;
This is a large and taxonomically complex subgenus in need of revision. The number of unpublished synonymies is large and a list of species is not given here. There is only one species in the
The pollen preferences of species included in the subgenus
This species-poor, group 2 subgenus is probably represented in the Palearctic by one conspicuous species that is well characterized in the key. In both sexes,
Apex of male metasoma, dorsal view.
Two species have been mentioned for the Palearctic region and for the Arabian Peninsula:
Gess and Roosenschoon (2017) provide a description of the nesting biology of
Genital capsule, lateral view.
There are at least 14 valid species in the Western Palearctic:
All species are leafcutters and build brood cells made of leaf fragments (e.g.
Most species of the subgenus
This subgenus is morphologically diverse and in both sexes few diagnostic traits are common to the entire subgenus. The description is given for the each species group. The rather distinct
There is only one Western Palearctic species each in the
The nesting biology of
There are at least seven species in the western Palearctic:
Most species of the sugbenus
This subgenus is widespread in Africa and in the Oriental zone. I have seen two specimens from Yemen, one male and one female, presumably from two different species: the female is sculpturally similar to
This subgenus is distributed in the tropical regions of Southeast Asia, from India to northern Australia; in China and Japan, it enters the East Palearctic region. I have examined one female (possibly
I have seen one single female from Yemen (
The review of the nesting biology of western Palearctic
This study has only been possible thanks to the continuous support of Maximilian Schwarz, to whom I express my deep gratitude. I also thank the curators of the Natural History Museum, London (David Notton), the Muséum national d’histoire naturelle, Paris (Claire Villemant and Agnièle Touret-Alby), the Senckenberg Naturmuseum, Frankfurt (Patricia Peters), the Museum für Naturkunde, Berlin (Frank Koch and Viola Richter), the Institute of Systematic Zoology of the Polish Academy of Sciences, Krakow (Lukasz Przybylowicz) and the Zoological Institute of the Russian Academy of Sciences, St. Petersburg (Yulia Astafurova) for the loan of type material or for hosting the author’s visits to their institutions. John Ascher, Fritz Gusenleitner, Margarita Hadjistylli, Michael Kuhlmann, Andreas Müller, Stephan Risch, Stuart Roberts, Christian Schmid-Egger and Jakub Straka have helped to clarify numerous taxonomic questions. All pictures were taken using the Keyence VHX 1000 digital microscope of the Musée d’histoire naturelle de Neuchâtel and the Centre Suisse de Cartographie de la Faune, Neuchâtel. I also thank Gérard Le Goff for numerous discussions on the biology of
Additional notes on the new synonymies
species data