Andrena (Chlorandrena) pastellensis Schwenninger, 2007

Wood, Thomas James, Praz, Christophe, Selis, Marco, Flaminio, Simone, Mei, Maurizio, Cornalba, Maurizio, Rosa, Paolo, Divelec, Romain Le & Michez, Denis, 2023, Revisions to the Andrena fauna of Italy, with the description of a new species (Hymenoptera: Andrenidae), Fragmenta entomologica 55 (2), pp. 271-310 : 284-285

Andrena (Chlorandrena) pastellensis Schwenninger, 2007 and Andrena (Chlorandrena) taraxaci Giraud, 1861

Schwenninger (2007) described A. pastellensis from Italy (regions of Valle d’Aosta, Veneto, Apulia, and Lombardy) and Switzerland, with a locus typicus of Monte Pastel- lo near Verona. Schwenninger diagnosed A. pastellensis against A. taraxaci initially based on geographic collecting locality, noting that separation of females could not be reliably carried out in all cases ( Schwenninger 2007: 642), then giving a determination table to allow differentiation of males based on the degree of tergal shagreenation and punctation, the size and form of the genital capsule, and the shape of S8. He also listed A. taraxaci as present in Italy based on a male and female from Trieste collected in 1918 (OÖLM). However, Schwenninger (2015) does not list A. taraxaci as present in Italy.

In presenting barcodes for Central European bees, Schmidt et al. (2015) presented a sequence of A. pastellensis from Valle d’Aosta and sequences of A. taraxaci from Czechia and Greece, and reported low genetic divergence between the two taxa. They noted that additional sequences from other members of the taraxaci -group were needed before strong conclusions could be drawn. With an analysis of the Schmidt et al. barcoded data with the addition of new sequences from Greece and Switzerland within the context of the taraxaci -group more broadly ( Fig. 7 ), the genetic distance between A. rhenana Stöckhert, 1930 and A. taraxaci sensu lato (that is, including A. pastellensis ) was 7.35% (range 6.56–8.16%). Andrena taraxaci and A. pastellensis formed two distinct clades separated by an average distance of 1.98% (range 1.56–2.33%), a value slightly above the maximal distance within A. taraxaci sensu stricto, 1.13% (distance between a specimen from Czechia and a specimen from Greece).

In the key of Schwenninger (2015), A. taraxaci and A. pastellensis males are separated at couplet 14, where the relative length of the genital capsule and S8, and the shape of the apex of the gonostyli are given as criteria to allow for recognition. In the female key, A. taraxaci and A. pastellensis do not fall together, as they are first separated at couplet 4 based on the colour of the hairs in the facial foveae and on the face more generally (brighter in A. pastellensis and darker in A. taraxaci ); the two taxa then key out separately, A. pastellensis at couplet 10 and A. taraxaci at couplet 13. This character is however somewhat artifi- cial and difficult to use, and does not capture all variation present, as some individuals from Italy to Switzerland can present some black hairs along the inner margins of the compound eyes, and the colour of the hairs in the foveae vary from light to light brown to darker brown. There are therefore female individuals that are difficult to unambig- uously place following the criteria of couplet 4. In direct comparison, the lightest A. pastellensis individuals from Italy do present terga that are comparatively more dull, and darker individuals of A. taraxaci from Greece do present terga that are comparatively more shiny, but across this west-east gradient, some intermediate individuals can be found, for example in Switzerland.

In this context, we take no taxonomic action here, but we highlight the small genetic divergence between the two taxa. Additional survey work is needed in north-eastern Italy combined with additional genetic sequences from this region and the western Balkans in order to determine if the observed genetic difference is consistent across a wider geographic range. We include both A. pastellensis and A. taraxaci on the Italian faunal list.

Material examined

( Andrena pastellensis )

ITALY: LOMBARDIA: ♂, Fara d’Adda (BG), 19 Apr 1916, leg. L. Micheli ( MSNM) . FRIULI-VENEZIA GIULIA: 4♀, San Vito al Tagliamento ( PN) , S. Paolo, Tagliamento river , 11 Apr 2014, leg. M. Snižek (OÖLM / TJWC) . EMILIA-ROMAGNA: 1♀, Bologna, Parco di Villa Ghigi , 30 Mar 2017, leg. G. Ghisbain ( TJWC) ; 1♀, Casalecchio di Reno (BO), 9 Apr 2015, leg. D. Benda ( JSCP) . LAZIO: 1♀, Cas- sino (FR), 15 Apr 2015, leg. D. Benda ( JSCP) ; 1♀, Mon- tecchio (RE), Parco Sorgenti Enza , 26 Mar 2021, leg. M. Violi ( MSVI) ; 1♀, Cicolano (RI), Cammino del Santi e del Briganti , 13 Jun 2021 ( MSVI) . ABRUZZO: 1♀, Rivisondoli ( AQ) , 1–7 Jun 1943, leg. C.N.R. ( MZUR) . SWITZERLAND: 1♂, 1♀, Canton Tessin, Bellinzona, Monte Cen- eri, 3 Apr 2007, leg. H.R. Schwenninger ( OÖLM) (paratypes of A. pastellensis ) ; 1♀, Maggia, Moghegno , 8 Apr 2021, leg. J. Litman & C. Praz ( TJWC) ; 1♀, Maggia, Torn , 8 Apr 2021, leg. J. Litman & C. Praz ( TJWC) .

( Andrena taraxaci )

AUSTRIA: 1♀, Krems an der Donau , 4 May 2008, leg. M. & Z. Halada ( OÖLM) ; 2♂, 6♀, Niederosterreich, 7 km NE Krems, Gedersdorf , 12 Apr 2009, leg. J. Halada ( OÖLM) ; 9♀, Oberosterreich, Plesching b. Linz , 1 May 1965, leg. H. Hamann ( OÖLM) ; 1♀, Steiermark, Neudorf d. Ilz , 14 Apr 1992, leg. E.R. Reichl ( OÖLM) . BULGARIA: 1♀, Charmanli [Harmanli], 16 May 1979, leg. M. Kocourek ( OÖLM) ; 2♂, 1♀, Kresna , 1–31 May 1967, leg. M. Kocourek ( OÖLM) ; 1♀, Kresna , 12 May 1979, leg. M. Kocourek ( OÖLM) ; 1♀, Kresna, Javorov , 1–31 May 2010, leg. P. Pacholátko ( OÖLM) ; 1♂, Lulun Geb. [Ly- ulin Mountain], 21 Apr 1964, leg. D. Marinova ( NZMS) ; 1♂, Plovdiv, Dzhendem Tepe , 200 m, 3–14 Apr 2002, leg. A. Stojanova ( NZMS) . CROATIA: 1♀, Solin, Nad Rupotinom , 302 m, 11 May 2018, leg. O. Polašek ( OÖLM) . CZECH REPUBLIC: 1♂, 1♀, Mor., Vyskov , 15 May 1965, leg. M. Kocourek ( NZMS) ; 1♀, Pouzdřany , 9 Jun 1959, leg. M. Kocourek ( OÖLM) ; 2♂, Pouzdřany , 18 Apr 1977, leg. M. Kocourek ( OÖLM) ; 2♀, Pouzdřany , 6 Jun 1980, leg. M. Kocourek, ( OÖLM) ; 1♂, 1♀, Úhřetice , 8 Apr 1989, leg. J. Odehnal ( OÖLM) . GREECE: 1♀, Eastern Macedonia and Thrace, Drama, Volakas , 1 km SSW of Volakas, 1000 m, 24 May 2023, leg. T.J. Wood ( TJWC) ; 1♀, Peloponnese, Rte. Skala-Neapoli , 15 Apr 1988, leg. H. Teunissen ( RMNH) ; 1♂, Samos, Platanos , ab. 600 m, 23 Apr 1988, leg. J.A.W. Lucas ( OÖLM). NORTH MACEDONIA : 1♂, 1♀, Polog reg., Sirichino , meadow, 430 m, 2–7 Apr 2021, leg. V. Bureš ( JSCP) ; 1♂, Vardar reg., Pape- liste, orchard, 140 m, 6–11 Apr 2021, leg. V. Bureš ( JSCP) . ROMANIA: 1♀, Nord-Dobrudgea, Enisala , 26 Apr 1996, leg. L. Rákosy ( OÖLM) . SLOVAKIA: 1♂, Košice , 1–30 Apr 1953, leg. M. Kocourek , NZMS; 1♀, Štúrovo , 2 Jun 1965, leg. M. Kocourek ( NZMS) . UKRAINE: 1♀, Dzhankoi distr., Solenoe [Solone Ozero], 3 May 2000, leg. V. Gurko ( OÖLM) ; 4♀, Eupatoria reg., Suvorovo [Suv- orovs’ke] vill., 1–30 Apr 2000, leg. V. Gurko ( OÖLM) ; 2♂, 4♀, Krim, Simferopol Umg. , 24–27 Apr 2003, leg. S. Iwanow ( OÖLM) .

Figures

Fig. 7 - Molecular phylogeny of the subgenus Chlorandrena Pérez, 1890, with a focus on Italian species. Maximum clade credibility tree found in Bayesian analyses of sequence data of the mitochondrial gene COI; numbers above branches indicate posterior probabilities; values below 0.5 are omitted. Outgroup taxa are not shown.