Research Article
Research Article
Annotated checklist of the Swiss bees (Hymenoptera, Apoidea, Anthophila): hotspots of diversity in the xeric inner Alpine valleys
expand article infoChristophe Praz§, Andreas Müller|, Dimitri Bénon, Mike Herrmann#, Rainer Neumeyer¤
‡ info fauna – Swiss Zoological Records Center, Neuchâtel, Swaziland
§ University of Neuchâtel, Neuchâtel, Switzerland
| ETH Zurich, Institute of Agricultural Sciences, Biocommunication and Entomology, Zürich, Switzerland
¶ Unaffiliated, Bienne, Switzerland
# Unaffiliated, Konstanz, Germany
¤ Unaffiliated, Zürich, Switzerland
Open Access


We present a checklist of the Swiss bees and provide information on the distribution of every bee species in all 26 Swiss cantons. 632 species are reported, including the European honeybee Apis mellifera Linnaeus, 1758 and the exotic species Megachile sculpturalis Smith, 1853. Species richness in each canton was correlated with the canton area, with the four largest cantons hosting the highest number of species. Bee diversity hotspots were located in some Alpine inner valleys characterized by a dry and warm climate due to the rain shadow effects of surrounding mountains. These hotspots are mostly located in the steppe-like habitats of the Valais and Graubünden cantons. They host diverse wild bee communities which include a unique assemblage of submediterranean faunal elements and subalpine species. In addition, these habitats host rare species with strongly disjunct distributions in Europe, further stressing the conservation priority of these habitats for wild bee conservation. Intensive faunistic surveys performed in the last 20 years have revealed that about 20 bee species, either previously unknown for Switzerland or which had disappeared from the country for several decades, have colonised areas close to the borders of France and Italy. Most of these new or reappeared species were observed in the warmest area of the country and presumably colonized or recolonized the country from neighbouring regions following global warming. Lastly, DNA barcodes are presented for 394 specimens, including for many species so far not represented in the BOLD database. The taxonomic status of numerous unclear taxa is briefly discussed based on combined genetic and morphological analyses.

Key Words

Bees, pollinators, conservation, DNA barcoding, biodiversity, biogeography


Despite its small size, Switzerland has received much attention from entomologists for more than a century. This is particularly true for the Alps which cover nearly 60% of the country, and which have attracted botanists and entomologists for a long time, resulting in numerous studies documenting the Swiss flora and fauna (see for example Morawitz (1867) for an early work on Swiss Alpine bees).

The first author who extensively studied the Swiss bee fauna was Emil Frey-Gessner (1826–1917; Carl and Steck 1918). After being employed as a teacher near Aarau, Frey-Gessner was for some time the curator of the Hymenoptera collection of the Natural History Museum in Geneva. He collected in different places in Switzerland, mostly around Geneva, but also in the Valais, in Ticino, and in some localities in the Alps. He also identified bees from other Swiss entomologists, mostly Baptiste Jacob (1830–1918; region of Neuchatel), Henri Tournier (1834–1904; region of Geneva), Moritz Paul (1835–1898; region of Sierre, Valais), Walter Schmid (1843–1904; region of Basel), Emile Favre (1843–1905; region of Martigny and Sierre), and Theodor Steck (1857–1937; regions of Bern and Basel). Frey-Gessner compiled the first monograph of the Swiss bees, published as supplements to the Mitteilungen der Schweizerischen Entomologischen Gesellschaft (Frey-Gessner 1899–1912). In this first treaty of the bees of Switzerland, 454 “species” and 52 “varieties” were recognized; translating these numbers into a precise count of species is difficult since these varieties include both colour morphs (e.g., Bombus mucidus var. mollis Pérez, 1879, the slightly lighter form of B. mucidus Gerstäcker, 1869) or valid species (e.g., B. pomorum var. elegans Seidl, 1837, the valid species now referred to as B. mesomelas Gerstäcker, 1869). The main part of his collection is preserved as a separate collection in the Natural History Museum of Bern; it is very well-preserved and still organized as Frey-Gessner originally arranged it, so that the records published in his monograph can be backed up with the precise specimens studied (see for example Blüthgen 1921). Frey-Gessner wrote locality information by hand on small labels (Suppl. material 1: fig. S1A); the date is only indicated as day and month; most specimens also bear a printed number, probably referring to a species catalogue; for some common localities, the locality is printed, the date (without year) being added by hand (Suppl. material 1: fig. S1A, B). His collection is remarkably well-maintained, with most specimens bearing locality labels; no apparently mislabeled specimens has been detected (but see comments under Epeolus alpinus Friese, 1893 for an obvious exception).

Jacques de Beaumont (1901–1985; see Besuchet 1986), a renowned sphecid wasp specialist, was the next important author who studied the Swiss bees, although his contributions on the bees were mostly a “by-product” of his intensive work on other groups of aculeate Hymenoptera, mostly the sphecid and pompilid wasps. De Beaumont, curator at the Museum of Zoology in Lausanne, collected bees in several regions of Switzerland, mostly western Switzerland, the Valais, Ticino, and the National Park region (Graubünden). He published three main accounts on the bees of Switzerland, two accounts on the bees of western Switzerland (de Beaumont 1955, 1960) and one account on the bees of the National Park region in the Graubünden (de Beaumont 1958). His well-preserved collection is mostly deposited at the Zoology Museum in Lausanne.

While de Beaumont and Frey-Gessner largely documented the wild bee fauna of western Switzerland, and to a very limited extent that of Ticino and of the National Park region in the Graubünden, large parts of Switzerland remained virtually uninvestigated until about 1960, especially the north-eastern corner, as well as Graubünden with the vast valleys of the upper Rhine river system. Even the eastern part of the Valais, corresponding to the German-speaking part of the Valais, perhaps the most remarkable entomological “hotspot” in Switzerland due to its dry and continental climate, also remained largely unexplored until well after 1950. As noted by Amiet (1991), Andrena probata Warncke, 1973 and A. ranunculorum Morawitz, 1877 (Fig. 1), two remarkable and for the former, conspicuous and locally abundant species (at least historically), were only recorded in Switzerland after 1975, probably because they occur in the less accessible eastern part of the Valais, a region that Frey-Gessner and de Beaumont hardly visited.

Figure 1. 

Andrena probata (left) and Andrena ranunculorum (right), two rare and emblematic species of the dry, inner Alpine Valleys of Switzerland. Pictures by Dimitri Bénon (

The intensive work of Erwin Steinmann (1923–2020; see Müller 2021) has partly contributed to fill these gaps in the knowledge of the Swiss bee fauna, at least for the eastern part of the country (Graubünden). As a passionate mountain hiker, Erwin Steinmann investigated the Swiss Alpine bee fauna like no one else. He published an account on the bee fauna of the dry inner Alpine valleys (Steinmann 2002). His collection is preserved in the Natural History Museum of Chur, Graubünden.

The Swiss bee fauna is and will forever be associated with the name of Felix Amiet, who has dedicated much of his life to the study of the Swiss bees. Felix Amiet started his work on the bees in the 1960s. After that and until now, he has explored every corner of Switzerland to study its bees. He has assembled the most comprehensive collection to date, with well-preserved specimens from all biogeographic regions of the country. His collection is preserved in the Natural History Museum of Bern. Felix Amiet published the first checklist of the Swiss bees (Amiet 1991), where 575 species are mentioned; he then coordinated the publication of the six volumes of the atlases on the Swiss bees, which include distribution maps and identification keys for all species, and which were published in the series Fauna Helvetica (Amiet et al. 19992017). A first volume on the genus Bombus was published in the series Insecta Helvetica (Amiet 1996). The publication of these well-known identification keys has been the opportunity for him and his coauthors to entirely revise the museum specimens preserved in Swiss institutions, initiating the creation of the important database that underlies the present work. The activities of F. Amiet and E. Steinmann paved the way for numerous surveys of the native bee fauna, which were carried out from the 1980s onwards, predominantly as part of student theses and expert reports in different regions of Switzerland.

Goal of the present checklist

The present checklist builds upon the previous work coordinated by Felix Amiet. Since 2012, much faunistic work has been conducted on the Swiss bees in a project aiming at updating the Red List of the Swiss bees; during this project, numerous inventories have been undertaken, partly in poorly investigated regions of Switzerland. Several new species for Switzerland have been found, and our knowledge of the distribution of the bees has substantially improved. In parallel, bee systematic studies have seen a renewed impetus, in part due to the increased use of genetic markers to delineate species, leading to numerous taxonomic changes in the central European fauna. Before the publication of the Swiss red list (Müller and Praz, in press), we wish to summarize all these changes in the present work. We thus present a revised checklist of all Swiss bee species, giving for each species its distribution in all cantons of Switzerland. We also comment on each species: i. if it is new for Switzerland; ii. if it is a recently described species, or a recently recognized taxon previously treated as a synonym; iii. if its current distribution is different from that previously published (Amiet et al. 20012017), for example due to identification errors, to the finding of new populations, or to marked range expansions; iv. if the taxon is referred to differently in recently published bee checklists in Europe (Ghisbain et al. 2023; Scheuchl et al. 2023; Reverté et al. in press) and v. if there are open taxonomic questions that require additional work.


Critical examination of ancient records

As in other central or northern European countries, the bee fauna of Switzerland has seen massive declines, which gradually began after the main rivers had been channeled and the lowland areas subjected to urbanization and agricultural intensification. The few scientific collections that predate these important changes are thus irreplaceable testimonies of historical bee diversity. Unfortunately, these collections are small and their geographic coverage very fragmentary; moreover, the standards for curating specimens, especially with respect to the locality information on the labels, were not those of today. Consequently, some of these collections are somehow problematic, and some records dubious, for example because the supposed locality information refers to the place of residence of the author, or simply because of labelling mistakes. We followed here the guidelines of Monnerat et al. (2015) to accept or reject records from such ancient collections. Briefly, a record is accepted if it originates from a “reliable” collection (see below), if a more or less accurate locality is indicated on the label, if this label is original (i.e., written by the collector and not recopied or added posteriorly; see Suppl. material 1: fig. S1), if the record is ecologically plausible (e.g., in term of phenology, habitat or, for cuckoo bees, the presence of the host), and if the record lies within the known potential or former distribution of the species in Europe.

Given the difficulties inherent in the identification of bees, we only validated records that are based on a preserved specimen; some old records based only on literature mentions are not validated (see for example the case of Andrena hystrix Schmiedeknecht, 1883, below). As indicated above, one criterion to validate or reject isolated records is whether the record lies within the overall distribution of the species in Europe (Monnerat et al. 2015), especially for species whose presence in Switzerland is based on a single specimen or a single collecting event. This criterion can prove challenging to evaluate given that the distribution of numerous bee species has drastically changed since the 19th century and given the poor knowledge of the historical distribution of numerous bee taxa in Europe (Tischendorf 2020). For example, Andrena incisa Eversmann, 1852, with numerous independent and reliable records in Switzerland between 1884 and 1939, is very rare in Europe, with ancient (<1970) records from Spain and Ukraine (as well as possibly Poland), and current records only from Turkey and Central Asia (T. Wood, pers. communication). To state that the records in Switzerland lie within the distribution of this bee in Europe would be a stretch, yet there are absolutely no doubts concerning these Swiss records. Similarly, numerous species with reliable historical records near Geneva and no other record in central Europe, are entirely unknown in nearby parts of France, with confirmed records only in southern France, more than 200 km from the Swiss records (e.g., Andrena mucida Kriechbaumer, 1873, with confident records in the Geneva region; see below). Accepting or rejecting a historical record, especially if based on a single specimen, is thus to some extent an arbitrary process. As stressed above, the historical record of bees in Switzerland (and generally in central Europe) is extremely incomplete; compared to other groups (e.g., Coleoptera or Lepidoptera), bees are underrepresented in historical collections; in addition, bee communities are highly dynamic, and some rare species such as cuckoo bees, are difficult to detect. It is thus not surprising that the repeated sampling of bees in particularly rich habitats will continue to uncover regionally new species even after decades of sampling, and that such repeated sampling produces lists of species characterized by a high number of singletons.

In some insect groups, occurrences based on isolated individuals are sometimes considered to represent erratic individuals (vagrants) outside their reproductive range. Examples include historical records of butterflies in southern Switzerland, for example Gonepteryx cleopatra (Linnaeus, 1767) in Ticino or Coenonympha dorus (Esper, 1782) in the Geneva region; both species are not considered to be native in Switzerland and were not evaluated in the red list of the Swiss butterflies (Wermeille et al. 2014). We did not adopt this approach for the Swiss bees, for the following reasons. First, there is no indication that bees have a migratory behavior, unlike numerous species of butterflies. Second, as indicated above, singletons are a common feature of all bee surveys, simply because some species are particularly hard to detect. For these reasons, we consider each species observed at least once within Swiss territory as native and potentially reproducing, with the exception of the exotic species Megachile sculpturalis Smith, 1853 and one recent, isolated record of Osmia latreillei (Spinola, 1806) (see below).

Unlike in some other insect groups, notably the Coleoptera (Monnerat et al. 2015), most Swiss collections of Hymenoptera can be considered as reliable. Two problematic collections with respect to the bees are those of Henri Tournier (1834–1904; Suppl. material 1: fig. S1G) and Walter Schmid (1843–1904; Suppl. material 1: fig. S1F). Tournier collected numerous specimens near his home in Peney (Satigny, Geneva), a small village located 250 m from the shore of the Rhone River. At that time, the Rhone River was not channeled, and Tournier was probably able to collect in vast sandy habitats near his house. He also exchanged material with other entomologists. Several records of Tournier supposedly from Peney have been suggested to be erroneous (e.g., de Beaumont 1946; Neumeyer 2008; Neumeyer and Merz 2012; Neumeyer 2014). Based on the examination of his entire bee collection, the majority of us conclude that the bee collection is overall reliable and that most specimens labeled with “Peney” (usually only indicated by “P.” and the date; Suppl. material 1: fig. S1G) were probably indeed collected near Peney. Another abbreviated locality is “R.” for “Reculet”, the highest peak of the Jura mountains, where Tournier collected an interesting series of bees, among other numerous specimens of Bombus mendax Gerstäcker, 1869, a species now extinct in the Jura. At Tournier’s time, many species were not yet described, especially in difficult species groups (e.g., Andrena, Lasioglossum, Nomada), and the knowledge of the bees in central Europe was very fragmentary, since the major catalogues and identification works (e.g., Dalla Torre 1896; Friese 18951901; Schmiedeknecht 1907) were not yet published. Despite this, the bees preserved in the Tournier collection, and labeled as being from Peney, do in fact belong to central European species, with only a few exceptions that are possibly based on mislabeled specimens (see below). As an illustration, we identified the numerous specimens of the subgenus Micrandrena of the Tournier collection, superficially very similar species that no one could identify at Tournier’s time. All Micrandrena specimens belong to species currently present near Geneva, or to species also collected by Frey-Gessner near Geneva at the same time as Tournier (Andrena distinguenda Schenck, 1871, A. floricola Eversmann, 1852, A. niveata Friese, 1887, A. pauxilla Stöckhert, 1935, and A. pusilla Pérez, 1903). The same is true for the species of the taxonomically challenging subgenus Taeniandrena. Nevertheless, some records represented by singletons in Tournier’s collection belong to species whose known distribution area does not encompass Switzerland. These records are possibly based on mislabeled specimens, and the records for three species are not accepted here (Andrena ventricosa Dours, 1873, Lasioglossum sphecodimorphum (Vachal, 1892) and Colletes nasutus Smith, 1853), following Monnerat et al. (2015). These cases are briefly discussed below.

The collection of Walter Schmid is slightly more problematic because the specimens were not labeled with original locality data by Schmid himself. All specimens in his collection bear a printed label that simply mentions “Basel, W. Schmid” (Suppl. material 1: fig. S1F), and it is probable that these labels were added after W. Schmid’s death. Consequently, some of Schmid’s records supposedly from Basel are probably erroneous (see for example Nomada gribodoi Schmiedeknecht, 1882, below); moreover, some records may originate from the much larger Basel region (including nearby France or Germany) and not from the Swiss Basel region. However, Frey-Gessner corresponded with W. Schmid and confirmed in his book some unique records for Switzerland, such as Andrena sericata Imhoff, 1868, Colletes collaris Dours, 1872 and Systropha planidens Giraud, 1861, all three of which occur north of Basel in the Rhine Valley, and which W. Schmid collected near Basel according to Frey-Gessner. We consider the historical presence of these species highly likely in the Basel region. Consequently, to simply discard all of W. Schmid records would be erroneous, and for this problematic collection we accepted occurrences that are plausible from a biogeographic point of view and that are backed up with a specific reference in Frey-Gessner’s book.

The Swiss bee dataset

All Swiss bee records, including those based on museum material, faunistic inventories or citizen-science based observations, are assembled into a database centralized at info fauna, Neuchatel ( The main task of info fauna is to maintain faunistic databases, to publish them as open resource at a low resolution (5 × 5 km) nationally and internationally, and to diffuse precise occurrence data to actors active in conservation, such as nature reserve managers and conservation agencies. The entire bee dataset can be accessed freely on GBIF (Praz et al. 2022), although in this open-access dataset the coordinates are rounded to a grid of 5 × 5 km; the underlying reason is that numerous occurrences are private, and for these private occurrences, the observer maintains exclusive ownership of the precise data. Distribution maps with a precision of 5 × 5 km can be accessed freely at and the biology of the Swiss species is summarized in a dedicated website (


Subspecies are not recognized in this dataset. In some cases, the initial database assembled for the publication of the identification keys by Amiet et al. (19992017) included subspecies. Overall, the recognition of subspecies is a controversial matter in systematics; it may make sense in some cases, for example to highlight incipient speciation, or for pragmatic, conservation purposes for geographically isolated units that may eventually be treated as a distinct taxon. However, the subspecies rank has also been used in the past for distinct colour morphs co-occurring in sympatry with regular-looking forms (e.g., the numerous forms within Bombus humilis Illiger, 1806, or Bombus confusus Schenck, 1859 and Bombus confususparadoxus” Dalla Torre, 1882), an approach that makes little sense since such forms do not represent significant evolutionary or conservation units. Overall, subspecies are not recognized in legal documents or by local conservation practitioners in Switzerland, and for such a small country, we see little need to recognize subspecies for bees. In some species, the Swiss populations belong to a recognized subspecies that is distinct form the nominal subspecies. An example in Lasioglossum limbellum (Morawitz, 1876): the nominal subspecies L. limbellum limbellum occurs eastwards from the Pannonian region of Austria, while the subspecies L. limbellum ventrale (Pérez, 1903) occurs westwards, including in Switzerland (Ebmer 1988). For practical reasons, we do not mention the subspecies in such cases (the subspecies are mentioned in Amiet et al. 20012017). We discuss below how we treat previously recognized subspecies (see for example under Halictus confusus Smith, 1853, Nomada panzeri Lepeletier, 1841, Panurginus montanus Giraud, 1861 and P. sericatus (Warncke, 1972)).

Species aggregates

In bees, there are numerous groups of species where a confident identification is only possible in fresh specimens or when some specific characters are visible, for example the male genitalia. In addition, only one sex can be identified with confidence in several groups. For example, the females of the Halictus simplex group (Halictus simplex Blüthgen, 1923, H. langobardicus Blüthgen, 1944 and H. eurygnathus Blüthgen, 1931) are nearly impossible to separate (Ebmer 1969; Amiet et al. 2001; Pauly 2015; pers. obs.). In such cases, all females were lumped in a species aggregate and the distribution data is inferred based on male specimens only. The different aggregates recognized in the Swiss database are listed in Table 1. For some difficult groups (e.g., the Bombus terrestris-group or the Hylaeus gibbus-group), an identification at the species level was only performed in typical specimens where a set of different morphological characters was in agreement. If one important morphological character was equivocal, the specimen was identified at the aggregate level.

Table 1.

The species aggregates recognized in the Swiss bee database.

Species aggregate Included species Remark
Lasioglossum alpigenum/bavaricum aggr. Lasioglossum alpigenum, L. bavaricum All females of these two species are included in this species aggregate, unless a DNA-based identification was performed.
Lasioglossum fratellum/subfulvicorne aggr. Lasioglossum fratellum, L. subfulvicorne All females of these two species are included in this species aggregate.
Hylaeus gibbus aggr. Hylaeus confusus, H. gibbus, H. incongruus Most specimens were identified using morphology; specimens that could not be re-rexamined recently, as well as morphologically unclear specimens, were included in this aggregate.
Panurginus montanus aggr. Panurginus montanus, P. sericatus Most females of these two species were included in this aggregate.
Andrena proxima aggr. Andrena alutacea, A. ampla, A. proxima Morphologically unclear specimens (mostly males, but also worn females) were included in this aggregate. All specimens from the Valais upstream from Martigny were assigned to A. ampla (McLaughlin et al. 2023).
Halictus simplex aggr. Halictus eurygnathus, H. langobardicus, H. simplex All females of these three species are included in this species aggregate, unless a DNA-based identification was performed.
Hylaeus taeniolatus/pictipes aggr. Hylaeus pictipes, H. taniolatus Females were systematically assigned to this aggregate until 2019; thereafter, most females were separated based on their morphology.
Bombus terrestris aggr. Bombus cryptarum, B. lucorum, B. magnus, B. terrestris All workers were included in this species aggregate, unless identified using DNA. Queens and males were mostly identified to the species level.

Generic classification

We adopt here the classification of Michener (2007) with a few exceptions, which are detailed here. Compared to previous work on the Swiss bees (Amiet et al. 20012017) this new classification leads to the break-up of the genus Anthophora into Anthophora and Amegilla, of the non-parasitic Anthidiini into the six genera Anthidiellum, Anthidium, Icteranthidium, Pseudoanthidium, Rhodanthidium and Trachusa, of the genus Osmia into Osmia, Hoplitis and Protosmia, of the genus Dioxys into the genera Allodioxys and Dioxys, and of the genus Epeolus into the genera Epeolus and Triepeolus. In contrast to Michener (2007), the genus Nomiapis is recognized for the species Nomiapis diversipes (Latreille, 1806) (formerly Nomia diversipes or Pseudapis diversipes), following Pauly (1990), Baker (2002), Astafurova and Pesenko (2006), Bossert et al. 2021 and Wood and Le Divelec (2022). Then, the genera Coelioxys and Dioxys are considered to be masculine (Rasmont et al. 2017). In the tribe Eucerini, several changes have recently been proposed (Dorchin et al. 2018; Freitas et al. 2023; Dorchin 2023), which result in the recognition of only two genera for the central European fauna, Eucera and Tetralonia, in contrast with the classification of Michener (2007) which recognized the genus Tetraloniella in addition to Tetralonia. The genus Eucera includes all two-celled species plus the three-celled subgenus Synhalonia, while the genus Tetralonia includes all other three-celled species, including species formally included in the genus Tetraloniella. Consequently, the three-celled species Eucera (Synhalonia) hungarica Friese, 1896 is treated here as a member of Eucera, not of Tetralonia as in Amiet et al. (2007). Lastly, we treat Seladonia as a subgenus of Halictus and not as a distinct genus, following Ebmer (1988), Michener (2007), Gibbs et al. (2012), Scheuchl and Willner (2016), and Scheuchl et al. (2023).

DNA barcoding

For the present work, numerous identifications have been verified using DNA barcoding, following lab protocols published elsewhere (e.g., Praz et al. 2019). Our general approach is to amplify the entire or part of the 658-bp “barcoding” fragment of the mitochondrial gene Cytochrome Oxidase I in two independent PCRs (Polymerase Chain Reactions) with the primers pairs LepF/LepR and UAE3/LepR (Suppl. material 2), producing fragments of 658 and 409 bp, respectively. These two PCRs can be done together with identical PCR conditions (see Praz et al. 2019, 2022). The PCR products were examined on an agarose gel; if both PCR worked, the 658-bp fragment was sequenced using the reverse primer LepR, and the 409-bp fragment with the forward primer UAE3; both sequences were assembled in Geneious Prime 2022.2.2, yielding the complete 658-bp fragment. For old specimens (> 10 years), often only the 409-bp fragment was successfully amplified, and this fragment was then sequenced bidirectionally with the primers UAE3 and LepR. The advantage of using two independent PCRs is that without increasing sequencing costs, the technique provides a way of checking for contamination or pipetting errors, as well as a way of minimizing the sequencing of nuclear pseudogenes (NUMTs). In addition, approximately 10% of the sequences produced with the primer pairs LepF/LepR in bees amplify Wolbachia DNA; this ratio was much lower with the primers UAE3/LepR. For some groups that failed to produce clear chromatograms with the primers LepF, LepR and UAE3, clade specific primers were developed; if neither the 658-bp nor the 409-bp fragments yielded clear chromatograms, these specific primers were used. A list of all primers used is given in Suppl. material 2.

We generated DNA barcodes with the following aims. First, in numerous cases, DNA-assisted identifications allowed to delineate the distribution of some species and generated confidently identified material to evaluate morphological criteria (see for example the case of the Hylaeus gibbus-group, below). Second, we generated DNA barcodes to evaluate the taxonomic status of some “forms” with unclear taxonomy. Lastly, we generated DNA barcodes for Swiss species not yet represented in DNA barcode libraries (, hereafter BOLD). All generated DNA barcodes have been submitted to BOLD; a full list of specimens for which DNA barcodes were generated, including locality information as well as BOLD accession numbers, is given in Suppl. material 3. In all figures, new sequences are indicated in red; all other sequences have been downloaded from the BOLD website.


The Swiss bee checklist

The database includes 473653 occurrences between 1817 and 2021 (inclusive), distributed in 7027 1 × 1-km grid cells; all records, even the historical records, are attributed to one 1 × 1-km grid cell, corresponding to the kilometer grid of the national topographic maps (; one occurrence may include several specimens when more than one specimen was collected at the exact same locality on the same day. The evolution of the database in time is shown in Fig. 2.

Figure 2. 

Evolution of the Swiss bee database over time, showing the number of occurrences (blue) and the number of sampled 1 × 1 km-quadrates (number of quadrates with at least one bee observation).

To date, 632 bee species have been recorded for Switzerland, including one exotic species, Megachile sculpturalis and the European honeybee, Apis mellifera Linnaeus, 1758. The distribution of these species in all Swiss cantons is given in Table 2 and Suppl. material 4.

Table 2.

Checklist of the Swiss bees, showing the presence of each species in each canton. Open circles indicate records before 2000, closed circles after 1999. Abbreviations: AG: Aargau; AI: Appenzell Innerrhoden; AR: Appenzell Ausserrhoden; BE: Bern; BL: Basel-Landschaft; BS: Basel-Stadt; FR: Fribourg; GE: Geneva; GL: Glarus; GR: Graubünden; JU: Jura; LU: Luzern; NE: Neuchâtel; NW: Nidwalden; OW: Obwalden; SG: St. Gallen; SH: Schaffhausen; SO: Solothurn; SZ: Schwyz; TG: Thurgau; TI: Ticino; UR: Uri; VD: Vaud; VS: Valais; ZG: Zug. This table is also available as a supplemental table (Suppl. material 4).

Species AG AI AR BE BL BS FR GE GL GR JU LU NE NW OW SG SH SO SZ TG TI UR VD VS ZG ZH Number of Cantons Number of Cantons (after 2000)
Aglaoapis tridentata 6 5
Amegilla albigena 2 1
Amegilla garrula 4 2
Amegilla quadrifasciata 3 0
Amegilla salviae 1 0
Ammobates punctatus 1 1
Andrena aeneiventris 5 3
Andrena afrensis 1 1
Andrena afzeliella 24 24
Andrena agilissima 13 9
Andrena alfkenella 16 14
Andrena allosa 6 6
Andrena alutacea 7 5
Andrena amieti 11 11
Andrena ampla 3 3
Andrena apicata 17 14
Andrena argentata 6 1
Andrena assimilis 2 0
Andrena barbareae 5 4
Andrena barbilabris 21 19
Andrena bicolor 25 25
Andrena bimaculata 6 4
Andrena bucephala 18 18
Andrena chrysopus 2 2
Andrena chrysosceles 26 26
Andrena cineraria 26 25
Andrena clarkella 16 14
Andrena coitana 11 7
Andrena combinata 19 16
Andrena confinis 10 3
Andrena congruens 9 4
Andrena curvungula 15 15
Andrena decipiens 3 0
Andrena denticulata 7 5
Andrena distinguenda 4 2
Andrena dorsata 23 23
Andrena falsifica 24 23
Andrena ferox 7 2
Andrena flavilabris 1 0
Andrena flavipes 22 21
Andrena florea 13 13
Andrena floricola 8 1
Andrena florivaga 1 1
Andrena freygessneri 4 2
Andrena fucata 23 21
Andrena fulva 20 19
Andrena fulvago 26 26
Andrena fulvata 25 25
Andrena fulvicornis 4 4
Andrena fulvida 5 4
Andrena fuscipes 4 3
Andrena fuscosa 1 0
Andrena gelriae 7 4
Andrena gravida 22 22
Andrena haemorrhoa 26 25
Andrena hattorfiana 25 23
Andrena helvola 23 22
Andrena hesperia 3 2
Andrena humilis 26 26
Andrena hypopolia 2 0
Andrena incisa 2 0
Andrena intermedia 20 17
Andrena labialis 13 13
Andrena labiata 25 24
Andrena lagopus 17 16
Andrena lapponica 15 14
Andrena lathyri 20 19
Andrena lepida 1 0
Andrena limata 7 2
Andrena livens 1 0
Andrena marginata 10 7
Andrena minutula 25 25
Andrena minutuloides 23 23
Andrena mitis 17 17
Andrena montana 5 5
Andrena mucida 2 0
Andrena nana 17 12
Andrena nanula 2 2
Andrena nigroaenea 21 17
Andrena nigroolivacea 9 9
Andrena nigrospina 3 0
Andrena nitida 25 25
Andrena nitidiuscula 17 15
Andrena niveata 5 2
Andrena nuptialis 2 1
Andrena nycthemera 6 0
Andrena ovata 2 1
Andrena pallitarsis 5 1
Andrena pandellei 17 17
Andrena parviceps 4 2
Andrena pauxilla 1 0
Andrena pellucens 1 1
Andrena pilipes 8 1
Andrena polita 7 6
Andrena potentillae 6 3
Andrena praecox 22 21
Andrena probata 2 1
Andrena propinqua 10 5
Andrena proxima 22 21
Andrena pusilla 4 1
Andrena ranunculorum 1 1
Andrena rhenana 3 3
Andrena rogenhoferi 12 12
Andrena rosae 20 16
Andrena ruficrus 14 14
Andrena rufizona 8 4
Andrena rufula 6 6
Andrena rugulosa 6 4
Andrena russula 12 8
Andrena saxonica 1 1
Andrena schencki 15 11
Andrena scotica 25 25
Andrena semilaevis 16 13
Andrena sericata 2 0
Andrena simillima 3 2
Andrena simontornyella 2 2
Andrena strohmella 24 24
Andrena subopaca 26 25
Andrena suerinensis 2 1
Andrena symphyti 2 1
Andrena synadelpha 7 3
Andrena taraxaci 2 2
Andrena tarsata 10 8
Andrena tenuistriata 1 1
Andrena thoracica 4 3
Andrena tibialis 19 19
Andrena tridentata 1 0
Andrena trimmerana 15 12
Andrena tscheki 1 0
Andrena vaga 21 21
Andrena varians 12 2
Andrena ventralis 21 20
Andrena viridescens 25 25
Andrena vulpecula 2 2
Andrena wilkella 24 24
Anthidiellum strigatum 24 23
Anthidium cingulatum 6 1
Anthidium florentinum 2 2
Anthidium loti 2 1
Anthidium manicatum 23 22
Anthidium montanum 16 15
Anthidium oblongatum 23 23
Anthidium punctatum 21 21
Anthidium septemspinosum 3 3
Anthophora aestivalis 21 20
Anthophora balneorum 3 1
Anthophora bimaculata 4 3
Anthophora canescens 1 0
Anthophora crassipes 2 1
Anthophora crinipes 10 9
Anthophora dispar 1 1
Anthophora fulvitarsis 2 0
Anthophora furcata 23 22
Anthophora mucida 2 1
Anthophora plagiata 7 4
Anthophora plumipes 25 24
Anthophora pubescens 5 3
Anthophora quadrimaculata 22 21
Anthophora retusa 4 4
Apis mellifera 26 26
Biastes emarginatus 3 2
Biastes truncatus 2 1
Bombus alpinus 7 6
Bombus argillaceus 3 3
Bombus barbutellus 26 26
Bombus bohemicus 26 25
Bombus campestris 23 23
Bombus confusus 12 1
Bombus cryptarum 12 9
Bombus distinguendus 4 1
Bombus flavidus 9 7
Bombus gerstaeckeri 14 14
Bombus hortorum 26 26
Bombus humilis 24 24
Bombus hypnorum 26 26
Bombus inexspectatus 3 3
Bombus jonellus 16 15
Bombus lapidarius 26 26
Bombus lucorum 26 26
Bombus magnus 1 0
Bombus mendax 15 14
Bombus mesomelas 16 12
Bombus monticola 15 14
Bombus mucidus 16 14
Bombus muscorum 16 9
Bombus norvegicus 22 21
Bombus pascuorum 26 26
Bombus pomorum 16 0
Bombus pratorum 26 26
Bombus pyrenaeus 14 13
Bombus quadricolor 18 10
Bombus ruderarius 24 22
Bombus ruderatus 18 17
Bombus rupestris 25 24
Bombus sichelii 17 13
Bombus soroeensis 26 26
Bombus subterraneus 19 16
Bombus sylvarum 23 21
Bombus sylvestris 26 25
Bombus terrestris 24 24
Bombus vestalis 22 22
Bombus veteranus 18 11
Bombus wurflenii 24 22
Ceratina chalcites 1 1
Ceratina chalybea 13 11
Ceratina cucurbitina 15 15
Ceratina cyanea 24 23
Ceratina gravidula 3 2
Ceratina nigrolabiata 1 1
Chelostoma campanularum 24 24
Chelostoma distinctum 20 20
Chelostoma emarginatum 3 1
Chelostoma florisomne 26 25
Chelostoma foveolatum 4 3
Chelostoma grande 7 4
Chelostoma rapunculi 25 24
Coelioxys afer 15 15
Coelioxys alatus 5 3
Coelioxys aurolimbatus 19 18
Coelioxys conicus 18 17
Coelioxys conoideus 13 6
Coelioxys echinatus 6 6
Coelioxys elongatus 19 19
Coelioxys emarginatus 1 0
Coelioxys inermis 16 15
Coelioxys lanceolatus 8 6
Coelioxys mandibularis 13 10
Coelioxys rufescens 22 21
Colletes collaris 1 0
Colletes cunicularius 22 22
Colletes daviesanus 18 18
Colletes floralis 3 3
Colletes fodiens 5 2
Colletes gallicus 2 0
Colletes hederae 22 22
Colletes impunctatus 6 6
Colletes marginatus 4 2
Colletes mlokossewiczi 2 1
Colletes nigricans 2 1
Colletes sierrensis 2 1
Colletes similis 21 21
Colletes succinctus 4 3
Dasypoda argentata 2 1
Dasypoda hirtipes 11 8
Dioxys cinctus 9 3
Dufourea alpina 9 8
Dufourea dentiventris 13 9
Dufourea halictula 1 1
Dufourea inermis 5 3
Dufourea minuta 5 3
Dufourea paradoxa 6 5
Epeoloides coecutiens 17 15
Epeolus alpinus 6 3
Epeolus cruciger 13 12
Epeolus fallax 1 1
Epeolus productulus 1 1
Epeolus variegatus 18 18
Eucera hungarica 1 0
Eucera interrupta 4 3
Eucera longicornis 23 22
Eucera nigrescens 25 24
Eucera nigrifacies 2 2
Eucera pollinosa 3 2
Halictus carinthiacus 5 5
Halictus confusus 17 16
Halictus eurygnathus 12 11
Halictus fulvipes 1 0
Halictus kessleri 2 0
Halictus langobardicus 15 14
Halictus leucaheneus 5 4
Halictus maculatus 20 19
Halictus quadricinctus 10 9
Halictus rubicundus 26 26
Halictus scabiosae 24 24
Halictus seladonius 3 2
Halictus sexcinctus 14 10
Halictus simplex 22 21
Halictus subauratus 21 21
Halictus submediterraneus 5 4
Halictus tectus 1 0
Halictus tumulorum 26 26
Heriades crenulata 10 7
Heriades rubicola 3 2
Heriades truncorum 25 24
Hoplitis acuticornis 2 1
Hoplitis adunca 23 22
Hoplitis anthocopoides 9 2
Hoplitis claviventris 25 24
Hoplitis dalmatica 3 3
Hoplitis lepeletieri 10 7
Hoplitis leucomelana 24 24
Hoplitis loti 14 13
Hoplitis mitis 15 10
Hoplitis papaveris 2 0
Hoplitis praestans 1 1
Hoplitis ravouxi 14 11
Hoplitis robusta 3 3
Hoplitis stecki 1 0
Hoplitis tridentata 16 15
Hoplitis tuberculata 16 10
Hoplitis villosa 17 16
Hylaeus alpinus 12 10
Hylaeus angustatus 15 10
Hylaeus annulatus 9 8
Hylaeus bifasciatus 3 0
Hylaeus brevicornis 23 23
Hylaeus cardioscapus 1 1
Hylaeus clypearis 17 16
Hylaeus communis 25 25
Hylaeus confusus 23 23
Hylaeus cornutus 15 15
Hylaeus crassanus 3 1
Hylaeus difformis 22 21
Hylaeus dilatatus 19 19
Hylaeus duckei 8 4
Hylaeus euryscapus 1 0
Hylaeus gibbus 16 15
Hylaeus glacialis 2 2
Hylaeus gredleri 22 22
Hylaeus hyalinatus 24 24
Hylaeus incongruus 16 15
Hylaeus intermedius 3 3
Hylaeus kahri 17 15
Hylaeus leptocephalus 15 11
Hylaeus moricei 3 2
Hylaeus nigritus 23 22
Hylaeus nivalis 8 8
Hylaeus paulus 11 8
Hylaeus pectoralis 6 4
Hylaeus pfankuchi 13 12
Hylaeus pictipes 9 6
Hylaeus pilosulus 1 1
Hylaeus punctatus 23 23
Hylaeus punctulatissimus 15 9
Hylaeus rinki 17 14
Hylaeus signatus 21 20
Hylaeus sinuatus 23 22
Hylaeus styriacus 21 20
Hylaeus taeniolatus 17 15
Hylaeus tyrolensis 13 11
Hylaeus variegatus 11 6
Icteranthidium laterale 3 1
Lasioglossum aeratum 9 6
Lasioglossum albipes 26 25
Lasioglossum albocinctum 3 2
Lasioglossum alpigenum 11 9
Lasioglossum angusticeps 2 2
Lasioglossum bavaricum 9 8
Lasioglossum bluethgeni 8 8
Lasioglossum brevicorne 5 3
Lasioglossum breviventre 3 1
Lasioglossum buccale 3 2
Lasioglossum calceatum 26 26
Lasioglossum clypeare 5 2
Lasioglossum convexiusculum 7 3
Lasioglossum costulatum 15 13
Lasioglossum cupromicans 16 16
Lasioglossum discum 3 2
Lasioglossum elegans 2 1
Lasioglossum euboeense 3 1
Lasioglossum fratellum 15 15
Lasioglossum fulvicorne 26 26
Lasioglossum glabriusculum 19 18
Lasioglossum griseolum 3 3
Lasioglossum intermedium 18 17
Lasioglossum interruptum 19 17
Lasioglossum laeve 6 1
Lasioglossum laevidorsum 4 3
Lasioglossum laevigatum 25 21
Lasioglossum laterale 1 1
Lasioglossum laticeps 24 24
Lasioglossum lativentre 21 21
Lasioglossum leucopus 24 21
Lasioglossum leucozonium 25 25
Lasioglossum limbellum 18 16
Lasioglossum lineare 16 15
Lasioglossum lissonotum 6 2
Lasioglossum lucidulum 16 16
Lasioglossum majus 11 10
Lasioglossum malachurum 24 24
Lasioglossum marginatum 13 12
Lasioglossum marginellum 3 2
Lasioglossum medinai 2 2
Lasioglossum minutissimum 15 14
Lasioglossum minutulum 11 9
Lasioglossum monstrificum 15 14
Lasioglossum morio 25 25
Lasioglossum nigripes 21 20
Lasioglossum nitidiusculum 20 18
Lasioglossum nitidulum 24 23
Lasioglossum pallens 16 16
Lasioglossum parvulum 21 21
Lasioglossum pauperatum 4 0
Lasioglossum pauxillum 24 24
Lasioglossum peregrinum 1 0
Lasioglossum pleurospeculum 5 4
Lasioglossum podolicum 3 3
Lasioglossum politum 20 20
Lasioglossum punctatissimum 23 23
Lasioglossum puncticolle 11 10
Lasioglossum pygmaeum 12 10
Lasioglossum quadrinotatulum 5 4
Lasioglossum quadrinotatum 3 0
Lasioglossum quadrisignatum 5 1
Lasioglossum rufitarse 23 21
Lasioglossum semilucens 20 20
Lasioglossum setulosum 2 2
Lasioglossum sexmaculatum 1 0
Lasioglossum sexnotatum 16 7
Lasioglossum sexstrigatum 17 17
Lasioglossum subfasciatum 12 2
Lasioglossum subfulvicorne 6 6
Lasioglossum subhirtum 2 2
Lasioglossum tarsatum 4 3
Lasioglossum transitorium 1 1
Lasioglossum tricinctum 12 12
Lasioglossum villosulum 25 25
Lasioglossum xanthopus 16 13
Lasioglossum zonulum 24 23
Lithurgus chrysurus 3 2
Macropis europaea 21 21
Macropis fulvipes 19 19
Megachile alpicola 24 22
Megachile analis 6 5
Megachile apicalis 6 2
Megachile argentata 20 19
Megachile centuncularis 23 23
Megachile circumcincta 23 23
Megachile ericetorum 25 23
Megachile flabellipes 2 1
Megachile genalis 1 1
Megachile lagopoda 9 4
Megachile lapponica 5 4
Megachile leachella 4 3
Megachile ligniseca 21 20
Megachile maritima 14 9
Megachile melanopyga 3 3
Megachile nigriventris 25 24
Megachile parietina 17 9
Megachile pilicrus 3 2
Megachile pyrenaea 10 7
Megachile pyrenaica 12 9
Megachile rotundata 12 12
Megachile sculpturalis 11 11
Megachile versicolor 22 20
Megachile willughbiella 26 26
Melecta albifrons 21 21
Melecta festiva 1 1
Melecta luctuosa 12 6
Melitta dimidiata 2 2
Melitta haemorrhoidalis 23 22
Melitta leporina 18 18
Melitta nigricans 20 19
Melitta tricincta 8 7
Melitturga clavicornis 1 1
Nomada alboguttata 19 17
Nomada argentata 6 3
Nomada armata 17 14
Nomada atroscutellaris 18 17
Nomada baccata 3 0
Nomada bifasciata 21 19
Nomada bispinosa 2 0
Nomada blepharipes 2 1
Nomada bluethgeni 1 0
Nomada braunsiana 8 3
Nomada carnifex 1 0
Nomada castellana 16 10
Nomada confinis 1 0
Nomada conjungens 18 12
Nomada connectens 1 0
Nomada discrepans 1 0
Nomada distinguenda 14 8
Nomada emarginata 8 5
Nomada errans 8 3
Nomada fabriciana 25 25
Nomada facilis 19 16
Nomada femoralis 10 4
Nomada ferruginata 12 8
Nomada flava 24 24
Nomada flavilabris 1 0
Nomada flavoguttata 26 26
Nomada flavopicta 18 17
Nomada fucata 18 17
Nomada fulvicornis 19 17
Nomada furva 3 1
Nomada fuscicornis 5 3
Nomada goodeniana 24 23
Nomada gransassoi 4 2
Nomada guttulata 16 13
Nomada hirtipes 17 16
Nomada integra 24 22
Nomada italica 1 0
Nomada kohli 4 4
Nomada lathburiana 20 18
Nomada leucophthalma 16 10
Nomada linsenmaieri 1 1
Nomada marshamella 25 23
Nomada mauritanica 2 0
Nomada melathoracica 10 1
Nomada minuscula 2 0
Nomada moeschleri 13 13
Nomada mutabilis 2 1
Nomada mutica 7 4
Nomada nobilis 1 1
Nomada obscura 6 5
Nomada obtusifrons 4 3
Nomada opaca 5 0
Nomada panurgina 2 0
Nomada panzeri 24 24
Nomada piccioliana 7 3
Nomada pleurosticta 2 2
Nomada posthuma 7 6
Nomada rhenana 6 1
Nomada roberjeotiana 3 0
Nomada ruficornis 24 22
Nomada rufipes 6 4
Nomada sexfasciata 20 19
Nomada sheppardana 16 13
Nomada signata 19 17
Nomada similis 5 3
Nomada stigma 10 2
Nomada striata