Stelis (Stelis) ornatula (KLUG, 1807)

KRATOCHWIL, Anselm, SMIT, Jan & AGUIAR, António F., 2018, Updated checklist of the wild bees of the Madeira Archipelago and the Selvagens Islands (Hymenoptera: Apoidea: Anthophila), Linzer biologische Beiträge 50 (2), pp. 1213-1228 : 1222-1224

Stelis (Stelis) ornatula (KLUG, 1807) : See comments on Hoplitis acuticornis.

Amegilla (Amegilla) quadrifasciata maderae ( SICHEL, 1868) : Based on males and females, A. maderae has been validly described by SICHEL (1868). According to DOURS (1869), the specimens from Madeira are only a variety (maderae) of A. quadrifasciata

(DE VILLERS, 1798). ALFKEN (1940) accepted the species status, but LIEFTINCK (1956, 1958) referred to the species as A. quadrifasciata (DE VILLERS, 1798) .

There are certain morphological differences: In A. quadrifasciata , the tergite bands are wider than the tergite terminal part. Tergite 1 has light hairs in the centre. In A. maderae the tergite bands are narrow, and tergite 1 has dark to black hairs in the centre (checked by A.W. Ebmer). H.-R. Schwenninger (Natural Museum of Stuttgart) analysed the genitalia of specimens from France (Agay, Saint Raphaël, Côte d’Azur), Lanzarote (Playa Blanca), and Madeira (Cabo Girão, Câmara de Lobos). Certain differences can be detected; however, there is morphological variation, so no clear separating characteristics could be found. Because of the lack of differences in the genital structures, the actual status is A. quadrifasciata maderae. Further morphological, morphometric, and molecular investigations will be necessary.

Bombus (Bombus) terrestris lusitanicus KRÜGER, 1956 : The Bombus taxon ‘ maderensis’ has been regarded as a species of its own by some authors ( ERLANDSSON, 1979, RASMONT, 1984). This was not accepted by RASMONT et al. (2008) and WILLIAMS et al. (2012). We will follow RASMONT et al. (2008), who assigned the specimens of the Madeira Archipelago to B. terrestris lusitanicus; see also COPPÉE (2012). The morphological characteristics of the former B. canariensis PÉREZ, 1895 , are not strongly divergent from the broad variation of B. terrestris s.l. However, a molecular genetic analysis by WIDMER et al. (1998) supported the distinctness of the Canary Island populations from the European mainland populations of B. terrestris . This indicates that they have a longer genetic separation on the archipelago and underlines that the populations are native.

Specimens from Madeira show genetic similarities to mainland populations of B. terrestris lusitanicus from the Iberian peninsula ( WIDMER et al. 1998). The variability at microsatellite loci is similar to that of Mediterranean island populations and larger than on the Canary Islands. The authors concluded that the occurrence of the mainland and Mediterranean mtDNA haplotype A on Madeira Island is indicative of a different evolutionary history. We classify B. terrestris lusitanicus as native and not introduced (see also comments concerning Bombus r. ruderatus ).

Bombus (Megabombus) r. ruderatus ( FABRICIUS, 1775) : This species was described by Fabricius in 1775 based on specimens collected by Joseph Banks (first expedition of the Endeavour led by Captain James Cook) on the stop they made in Madeira in September 1768 ( FABRICIUS 1775, BOIEIRO et al. 2015). The locus typicus of B. r. ruderatus is therefore Madeira Island. Bombus r. ruderatus is also distributed on the Iberian Peninsula. The central European subspecies is B. r. eurynotus (DALLA TORRE, 1882) .

According to RASMONT (1983), B. r. ruderatus is distributed on the Azores too (see also YARROW 1967), and was introduced in the Azores ( WEISSMANN et al. 2017), firstly recorded in 1865 ( GODMAN 1870). On Tenerife, B. ruderatus is actually an invader (PÉREZ & MACÍAS- HERNÁNDEZ 2012).

Already in the fourteenth century, ships regularly docked on Madeira Island on their return from the Canaries. In our opinion we cannot exclude a man-made unintentional introduction. If we compare the distribution with that of B. t. lusitanicus on Madeira, B. ruderatus is restricted to lower altitudes, and the preferred habitats are rural sites, and the preferring flowering ressources are rural plant species. This is not the case for B. t. lusitanicus, which is also common on Porto Santo, has a habitat preference for the trade wind zone, and is characterised by visiting the flowers of many native plant species (especially Echium); see KRATOCHWIL & SCHWABE (2018a). We studied the flowervisiting behaviour of B. t. lusitanicus intensively on Porto Santo.

Further investigations (especially population genetic analyses) are necessary to determine the rank of ‘native’ or ‘introduced’.