Unexpected levels of cryptic diversity in European bees of the genus Andrena subgenus Taeniandrena (Hymenoptera, Andrenidae): implications for conservation Author Praz, Christophe https://orcid.org/0000-0003-2649-3141 University of Neucha ̂ tel, Institute of Biology, Rue Emile-Argand 11, 2000 Neucha ̂ tel, Switzerland & InfoFauna - Swiss Zoological Records Center, Avenue de Bellevaux 51, 2000 Neuchatel, Switzerland christophe.praz@unine.ch Author Genoud, David Avenue des Roses 2, 87240 Ambazac, France Author Vaucher, Killian University of Neucha ̂ tel, Institute of Biology, Rue Emile-Argand 11, 2000 Neucha ̂ tel, Switzerland & InfoFauna - Swiss Zoological Records Center, Avenue de Bellevaux 51, 2000 Neuchatel, Switzerland Author Benon, Dimitri University of Neucha ̂ tel, Institute of Biology, Rue Emile-Argand 11, 2000 Neucha ̂ tel, Switzerland & InfoFauna - Swiss Zoological Records Center, Avenue de Bellevaux 51, 2000 Neuchatel, Switzerland Author Monks, Joseph Natural History Museum, Cromwell Road, London, UK Author Wood, Thomas J. https://orcid.org/0000-0001-5653-224X Laboratory of Zoology, University of Mons, Avenue du Champs de Mars 6, 7000 Mons, Belgium text Journal of Hymenoptera Research 2022 2022-06-30 91 375 428 http://dx.doi.org/10.3897/jhr.91.82761 journal article http://dx.doi.org/10.3897/jhr.91.82761 1314-2607-91-375 3A5B959985024CB7A83ECAA998B678A9 3F1971FA0B4150AD801E63777D5EB924 Andrena afzeliella (Kirby, 1802) stat. rev. Figs 3 , 4 , 9 , 19 , 29 , 31 , 33 , 35 , 45 Melitta afzeliella Kirby, 1802: 169, ♀, "Barhamiae" [Barham, Suffolk, England]. Lectotype ♀ (NHML), by present designation (see below). Melitta fuscata Kirby, 1802: 167, ♀, "Barhamiae" [Barham, Suffolk, England], Syn. nov. Lectotype ♀ (NHML), by present designation (see below). Andrena canescens Schenck, 1853: 140, ♂, "Schierstein" [Schierstein, Wiesbaden, Germany], Syn. nov. Holotype ♂ (MWNH). Andrena albofasciata Thomson, 1870: 154, ♀ ♂, "Saellsynt pa Skanes sandmarker" [Rare on the sandy grounds of Scania; Sweden], Syn. nov. Lectotype ♀, by designation of Niemelae 1949 : 117; see also Nilsson 2010 : 78 (ZML). Andrena afzeliella var. heliopolis Friese, 1914: 227, ♀ [Egypt]. Holotype ♀ (ZMHB) Andrena pseudovatula Alfken, 1926: 107, ♂ [Egypt]. Syn. nov. Syntype ♂ (SMFD) Material examined. Type material: Lectotype ♀ of Melitta afzeliella Kirby, 1802 (Figs 3 , 4 ), by present designation, a female in moderately good condition ( Anthrenus damage visible on head and legs, antennae missing) (NHML). This female specimen is labelled as follows: 1. "6339" [handwritten on blue paper disc, NHML accession number 1863-39]; 2. "B" [handwritten]; 3. " Lectotype " [printed on white paper disc]; 4. " Lectotype ♀ Andrena afzeliella des. Wood and Monks, 2022" [printed]; 5. "NHMUK 012858874". Figures 3-6. 3, 4 Lectotype female of Andrena afzeliella (Kirby, 1802) 3 profile 4 terga and terminal fringe. Copyright for these two images belongs to the trustees of the Natural History Museum, London 5, 6 lectotype female of A. russula Lepeletier, 1841 5 profile 6 terga. Lectotype ♀ of Melitta fuscata Kirby, 1802, by present designation, a female in good condition (NHML). This female specimen is labelled as follows: 1. "6339" [handwritten on blue paper disc, NHML accession number 1869-39]; 2. " Syntype " [printed on white paper disc]; 3. "B.M. Type/Hym/ 17a 2941" [handwritten]". 4. " Syntype ♀ Melitta fuscata Kirby det. D. Notton 1995"; 5. " Lectotype " [printed on white paper disc]; 6. Lectotype ♀ Andrena fuscata des. Wood and Monks, 2022" [handwritten]; 7. " NHMUK 014030702". Holotype ♂ of Andrena canescens Schenck, 1853, a male in good condition (MWNH; examined by CP); see Andert (2010) for details. Since the original description does not specify the number of specimens, unlike in similar cases (e.g., A. gibba ), and only mentions a single locality, it is assumed that the original description was based on this unique specimen, which is considered to be the holotype (by monotypy). Holotype of Andrena afzeliella var. heliopolis Friese , 1914. Egypt : ♀ , no locality information (ZMHB). Syntype of Andrena pseudovatula Alfken , 1926. Egypt : ♂ , no locality information, A. Andres leg. (SMFD) . Other material : Specimens from the UK , France (including Corsica ), Switzerland , Italy (including Sardinia ), the Netherlands , Germany , and Israel have been barcoded. Additional sequences are available on the BOLD website for specimens from Austria , Croatia and Georgia . Full details of examined material can be found in Suppl. material 2: Table S2. Distribution. Widespread and abundant in Europe (Fig. 7 ) from the Iberian Peninsula, France including Corsica, UK, Germany, Switzerland, Italy including Sardinia and Sicily, Scandinavia, Eastern Europe, Turkey, Cyprus, Lebanon, Syria, Israel, Jordan, Egypt, and Iran (see notes on Andrena afzeliella var. heliopolis Friese, 1914 below, "geographic variation"). This species may reach Kazakhstan under the name A. ovatula transcaspiensis Osytshnjuk, 1994. Figure 7. Distribution map of Andrena ovatula (blue dots) and A. afzeliella (red dots). Pollen preferences. Analysis of 37 pollen loads from 19 localities suggests polylecty with a strong preference for Fabaceae , with 91.7% of pollen collected from this family. Rosaceae , Plantaginaceae , Boraginaceae , Cornaceae , Ranunculaceae , Brassicaceae , Dipsacaceae , and Asteraceae were detected in decreasing order of abundance (TJW, unpublished data). Use of Fabaceae pollen is more pronounced in the summer generation. Westrich (1989) listed " A. ovatula " as polylectic, with three botanical families utilised for pollen ( Fabaceae , Asteraceae , Brassicaceae ) - these observations probably relate to A. afzeliella which is more common in Central Europe. Phenology. Andrena afzeliella is clearly bivoltine, with the peak of the first generation in May and early June, and that of the second generation in July and August (Fig. 8 ); where A. afzeliella and A. ovatula occur in sympatry, the first generation is found approximately one month after that of A. ovatula (Fig. 8 ), as already indicated by Stoeckhert (1930 ; see Nilsson 2010 ). Figure 8. Phenology of Andrena ovatula (blue bars) and A. afzeliella (red bars) based on all examined specimens from Belgium, Netherlands and United Kingdom. Note. The status of this species, in particular its distinctiveness from Andrena ovatula has been a controversial topic, and consequently the identity of A. afzeliella , A. albofasciata and A. ovatula in the literature is confusing ( Gusenleitner and Schwarz 2002 : 565). Early work did not discriminate between these two taxa and the name A. afzeliella was used for both (e. g. Perkins 1888 ; Saunders 1896 ; Alfken 1905 ; Frey-Gessner 1899-1907 ; Schmiedeknecht 1907 ) until Perkins (1917 , 1918 ) revised Kirby's type material for the British species of Taeniandrena , resurrected A. ovatula and placed A. afzeliella in synonymy with A. ovatula . The variability in the colour of the terminal fringe in the female was noted by several authors, for example by Schmiedeknecht (1907) , who attributed it to inter-generational variation. Stoeckhert (1930) was the first to suggest the presence of two distinct, bivoltine species in Europe: he recognised a slightly larger species with comparatively dark vestiture, A. ovatula sensu stricto , and a smaller species with light vestiture, A. albofasciata . Niemelae (1949) presented an identification key to the northern European species of Taeniandrena , including A. ovatula and A. albofasciata . Both taxa were later synonymised by Warncke (1967 : 206) but were mentioned in the identification key by Schmid-Egger and Scheuchl (1997) , who listed the criteria of Niemelae (1949) , stating however that they did not examine specimens of A. albofasciata from Germany. The distinctiveness of A. ovatula and A. albofasciata was then advocated by J. van der Smissen, who wrote that she could unambiguously separate these two taxa in northern Germany based on Niemelae's key (van der Smissen 2002 ). She later presented a detailed key to Northern European Taeniandrena , including A. ovatula and A. albofasciata (van der Smissen 2010 ). Ongoing confusion after her work is possibly due to the fact that A. albofasciata appeared to be rarer than A. ovatula in the region studied by J. van der Smissen in northern Germany; A. albofasciata was categorised as "probably endangered" in the red list to the bees and wasps of Schleswig-Holsteins while A. ovatula was treated as "least concern" (van der Smissen 2001 ). The assumption that A. albofasciata was restricted while A. ovatula was widespread probably explains why the identity of these two taxa has remained unclear until now (but see Herrmann 2007 ). In a recent DNA barcoding study of the bees of Germany, Schmidt et al. (2015) presented barcodes for five specimens identified as A. ovatula and for one specimen identified as A. albofasciata ; based on the shared barcodes of these six specimens, the authors suggested to treat these two species as synonyms. It appears however, that all specimens were in fact conspecific and belonged to A. albofasciata (see below). Our initial DNA barcodes of Swiss and French A. ovatula sensu lato were similar to those obtained by Schmidt et al. (2015) . Surprisingly, one sequence from Spain (see Wood et al. 2021 ) was 100% identical to a published sequence from Ireland (BOLD number IBBP050-10), originating from a specimen identified as A. ovatula , and widely divergent from all other specimens of A. ovatula sensu lato (Fig. 2 ). We then sequenced several additional specimens from numerous locations in Europe (Suppl. material 1: Table S1 and Fig. 2 ), including specimens identified as A. ovatula sensu stricto and A. albofasciata by J. van der Smissen from northern Germany. All female specimens with a dark terminal fringe ( A. ovatula sensu Stoeckhert , Niemelae and van der Smissen) formed a monophyletic clade including the sequence of A. ovatula from Ireland; this clade was widely separated from a clade containing all the female specimens with a light terminal fringe ( A. albofasciata ), as well as all the specimens sequenced by Schmidt et al. (2015) . Although a clear morphological separation of these two species is sometimes challenging, e. g. in worn females and in some males, this clear segregation of the two colour forms among two widely separated clades is a strong indication that two distinct species exist in sympatry in Europe. In addition, other subtle differences can be found in the sculpture or the vestiture colour (see below), leaving no doubts that these two species are distinct. At the European scale, A. albofasciata is much more widespread and abundant than A. ovatula ; in some parts of central Europe (see also Herrmann 2007 ), e.g., in Switzerland, only A. albofasciata appears to be present (Fig. 7 ). Lastly, a clear phenological difference is visible, at least for the first generation, as already noted by Stoeckhert (1930) : A. ovatula is active from the end of March to the End of May, with a peak around April, while the first generation of A. albofasciata is found from the beginning of May until mid-June (Fig. 8 ; note that this figure is only based on records from Belgium, UK and the Netherlands to reduce variability caused by seasonal differences across a latitudinal gradient). With respect to the names that can be applied to these two species, five names proposed by Kirby (1802) for the English fauna are currently placed as synonyms of A. ovatula sensu lato ( Perkins 1918 ; Gusenleitner and Schwarz 2002 ); of these five names at least three have been used as valid names after 1899: A. ovatula , A. afzeliella and A. fuscata (Kirby, 1802). These names may apply to either taxon since both occur in England (Figs 2 , 7 ). As far as we know, their type material has not been revised since Perkins (1918) . No syntype of A. picipes (Kirby, 1802) and A. barbata (Kirby, 1802) are preserved in the Kirby collection and these names are considered here to be nomina dubia . Perkins (2017: 50) mentions that he has examined the type of A. picipes in the Drury collection (possibly in OUMNH). Three males are preserved under A. ovatula in the Kirby collection (NHML). The original description of Kirby mentions a female (" Descr: Acul. " [the "aculeate sex" = the female]); however, as noted by Perkins (1918) , this was likely a mistake and Kirby's description probably corresponds to a male (the flocculus is not mentioned, unlike in other descriptions of females). We are not confident in the identification of these three males: the tergal structure is suggestive of A. ovatula sensu Stoeckhert (1930) , but the antennal ratio is not clear; the genitalia are not exposed. To settle the identity of this species while minimising changes to current usage of A. ovatula and A. albofasciata , we propose to designate a neotype for A. ovatula , selecting a barcoded female from Surrey, UK (see below under A. ovatula ). This neotype will ensure that the name A. ovatula continues to apply to the species referred to as A. ovatula by the few authors who have separated A. ovatula from A. albofasciata ( Stoeckhert 1930 ; Niemelae 1949 ; van der Smissen 2002 , 2010 ). Preserved syntypes of A. afzeliella in the Kirby collection include three females and one male, all of which probably belong to " A. albofasciata " (one female and the male are stylopised, rendering identifications challenging); the best-preserved female (Figs 3 , 4 ) clearly corresponds to " A. albofasciata " based on the colour of the terminal fringe (Fig. 4 ) and the hairs flanking the basitibial plate. This female is designated as the lectotype of A. afzeliella . Andrena albofasciata is placed in synonymy with A. afzeliella (syn. nov.). A reversal of precedence (article 23.9 of the Code of Zoological Nomenclature) to maintain the prevailing usage of A. albofasciata is not justified since A. afzeliella has been used as a valid name after 1899 (e.g., Alfken 1905 ; Frey-Gessner 1899-1907 ; Schmiedeknecht 1907 ), therefore rejecting the first condition of article 23.9 of the code. We tried to locate the type material of the Taeniandrena taxa described by A. Schenck, namely A. albofimbriata Schenck, 1853, A. canescens , A. distincta Schenck, 1861, A. gibba Schenck, 1853, A. octostrigata Schenck, 1853, A. ovata and A. plantaris Schenck, 1853. In the Schenck collection (SMFD), several specimens are preserved under the names Andrena wilkella , xanthura , Andrena afzeliella and Andrena convexiuscula . These specimens belong to several species including A. lathyri (see Alfken 1899 ), A. wilkella and A. afzeliella , and possibly others. No specimen can be identified as syntype since no mention of the names of the taxa described by Schenck can be found, neither on labels on the specimens, nor anywhere in his collection. We conclude that either the types have been lost or destroyed, or, alternatively, Schenck himself removed these labels, possibly because he thought that his taxa were conspecific with previously described species. Support for the latter hypothesis comes from the fact that Schenck (1861 : 255) places most of the taxa that he previously described in synonymy with " A. convexiuscula ". However, Schenck described numerous taxa based on material collected by C. Kirschbaum, and some of the type material for these taxa is preserved in the Kirschbaum collection (MWNH; Andert 2010 ). In addition to the male specimen of A. canescens mentioned above, two specimens of A. gibba are preserved and were examined. Both are stylopised, although one specimen mostly shows male characters and the other mostly female characters; these two specimens correspond to the original descriptions of the male and female of A. gibba , respectively. The identity of these two specimens cannot be established, although the first specimen probably belongs to either A. afzeliella or A. ovatula . A. gibba is thus treated as a nomen dubium . Similarly, A. albofimbriata , A. distincta and A. octostrigata are treated as nomina dubia given that their type material is presumably lost. A. ovata represents a distinct species (see below). Several additional names are currently treated as synonyms of A. ovatula sensu lato ( Gusenleitner and Schwarz 2002 ). The list of synonyms given here is incomplete. It is probable that most of these names will eventually be placed in synonymy with A. afzeliella . Diagnosis. Andrena afzeliella and A. ovatula can be separated from the other central European species of Taeniandrena by a combination of characteristics, which are summarised in the identification key given below. The criteria allowing separation of A. afzeliella and A. ovatula are presented in Table 1 . Males are often more difficult to separate than females and a confident identification is not possible in every case. Table 1. Comparison of Andrena afzeliella stat. rev. and A. ovatula (modified from van der Smissen 2010 ).

Females
Characters (order of importance)	Andrena afzeliella	Andrena ovatula
Apical fringe of T5	Golden (Figs 4 , 9 ) to whitish grey, rarely brown medially (Fig. 9 ), but never dark brown	Always dark brown to black medially, often lighter laterally (Fig. 10 )
Pygidial fimbria	Mostly whitish laterally, light brown medially, sometimes entirely golden (Fig. 4 ), rarely brown (Fig. 9 ), but then with a reddish hue, not dark brown	Dark brown medially (sometimes a few light brown hairs laterally), without reddish hue (Fig. 10 )
Apical fringe of hairs on femur, covering the base of basitibial plate	Orange to brown orange, never dark brown (Fig. 29 )	Dark brown (Fig. 30 )
Colour of scopal hairs	Entirely white or yellowish (Fig. 29 )	White or yellowish, but nearly always with a few dark hairs dorsally near basitibial plate (Fig. 30 )
Scutal vestiture	Long hairs yellowish white in fresh specimens; without short, dark hairs beneath long hairs (short hairs, if present, yellowish white).	Long hairs brownish yellow in fresh specimens; medially with dark, minute hairs beneath long hairs; this character is clearly visible in northern European populations, less so on the Iberian Peninsula.
Clypeal punctation and sculpture	On average comparatively fine and sparse (Fig. 31 ), sculpture matt, although there is considerable variation in this character and the condition overlaps with that observed in A. ovatula.	On average comparatively coarse, sculpture shiny (Fig. 32 ).
Size	On average slightly smaller, body length mostly 8-9 mm, although some specimens are up to 10 mm.	On average slightly larger, body length 9-10 mm
Males
Character (order of importance)	Andrena afzeliella	Andrena ovatula
Antennal ratio	A3 = 0.9-1.0 x A4 (Fig. 35 ); A5-A12 only slightly longer than broad.	A3 = 0.8-0.9 x A4 (Fig. 36 ); A5-A12 visibly longer than broad.
Sculpture of disc of T3 and T4	Shiny, punctation coarse and comparatively sparse (Fig. 33 )	Shagreened, punctation dense and shallow, punctures little visible (Fig. 34 )
Gonostylus and valve	Gonostylus broader, external margin often straight; valve often slightly broader (Fig. 45 )	Gonostylus more slender, external margin always concave, valve often more slender (Fig. 46 )
Gonocoxae	Internal margins usually diverging apically (Fig. 45 )	Internal margins usually parallel apically (Fig. 46 )
Vestiture	Body vestiture often entirely greyish white even in fresh specimens (Fig. 33 ), although sometimes yellowish brown, especially in first generation	Body vestiture yellowish brown in fresh specimens (Fig. 34 )
Width of tergal fringes	comparatively broad (Fig. 33 )	comparatively narrow (Fig. 34 )

Geographic variation. Andrena afzeliella is widely distributed in the Western Palearctic. Two barcoded specimens from Corsica and from Sardinia, respectively, clustered with continental populations of A. afzeliella in our phylogenetic tree (Fig. 2 ); in these two specimens, as well as in other examined specimens from Corsica and Sardinia, the mesosomal and head vestiture is orange-red, the terminal fringe is dark brown-orange (as on Fig. 11 ), and the integument of the hind femora is partly orange (as in Fig. 21 ; see Table 2 ). We examined specimens from Israel, Lebanon, Syria, Jordan, Egypt, and Iran with the integument of the metasoma partly to extensively red, most typically on T1-2, but sometimes the red colouration extends to all terga. Where long sequences of specimens from the same site and day were available from Egypt, specimens vary from entirely black to red-marked forms. We therefore consider tergal colouration to be variable, and retain A. afzeliella var. heliopolis , caracterized by the red integumental colour, as a simple colour form of A. afzeliella . Table 2. Comparison of the females of Andrena antonellae sp. nov., and those of the populations of A. afzeliella and A. wilkella from Corsica and Sardinia. Andrena wilkella has so far only been reported from Corsica.

Characters (order of importance)	Andrena afzeliella	Andrena antonellae sp. nov.	Andrena wilkella
Apical fringe of T5 and pygidial fimbria	Brown-orange (bronze)	Brown-orange (bronze)	Greyish brown
Sculpture of T1	Fine but distinct on disc and on margin; underlying surface weakly shagreened, shiny	Mostly impunctate, sometimes with a few, scarcely visible punctures on disc and margin; underlying surface shagreened, weakly shiny (Fig. 21 )	Fine but distinct on disc and margin, denser than in A. afzeliella but less so than in central European specimens of A. wilkella ; underlying surface weakly shagreened, shiny
Sculpture of T2	Very densely punctate, punctures separated by less than 0.5 puncture diameters; underlying surface weakly shagreened, shiny; margin impunctate	Mostly impunctate, sometimes few barely visible punctures on disc (Fig. 21 ).	Moderately densely punctate, punctures separated by 1-2 puncture diameters (punctation less dense and less visible than in central European populations); underlying surface weakly shagreened, shiny; margin impunctate
Sculpture of T4	Very finely and very densely punctate, interspaces less than a puncture diameter, surface appearing shagreened	Very finely and very densely punctate, interspaces less than a puncture diameter, surface appearing shagreened (Fig. 11 ).	Finely and densely punctate, interspaces above one puncture diameter, surface appearing shiny
Colour of integument	Margin of T1-4 dark, sometimes slightly brownish apically. Femora 3 predominantly orange.	Margin of T1-4 predominantly yellowish brown, dark brown only basally (Fig. 21 ). Femora 3 predominantly orange (Fig. 21 ).	Margin of T1-4 entirely dark. Femora 3 dark.
Body size	8-9 mm	8-9 mm	10-11 mm