Dispersion of Bumblebee Bombus Semenoviellus Skorikov (Hymenoptera, Apidae) in Poland

Bombus semenoviellus is a medium-sized bumblebee with a short tongue. On its black hairy body there are three yellow stripes, two on the thorax and one on the first segment of the abdomen. The tip of the abdomen has white hairs. In addition, there are yellow hairs on the head and legs (Fig. 1). In males there is a larger admixture of yellow hairs on the body and also on the head. Hairs are uneven and puffy.

Fig. 1

B. semenoviellus is widespread in the Palaearctic region (Williams, 1998) distributed in eastern and western Europe, from 48° (south) to 64° latitude, from western Germany to central Siberia. This species occurs mainly in Russia as a typical taiga bumblebee characteristic for birch forests (Skorikov, 1922). In Poland, it is known to be in dispersed locations but most often has been recorded in the central and northern parts of the country (Pawlikowski, 2008). Even though this short-tongued bumblebee prefers mid-forest meadows and forests, subsequent observations show that the bumblebee during its expansion to the west has begun to occupy heaths, swamps, anthropogenic habitats and gardens (Sima & Smetana, 2012).

Not much is known about B. semenoviellus biology, nesting sites or family size. Its brood cuckoo bumblebee parasite is unrecognized. Seasonal activity lasts probably from May to August (Pawlikowski, 2008). In the European Red List of Bees it has been given the status of least concern (LC) and in Poland has the status of a semi-protected species (Pawlikowski & Pawlikowski, 2012; Nieto et al., 2014).

It is a polylectic species that most often visits flowers of Trifolium pratense L., Hieracium murorum C.B. Clarke, Inula spp., Primula spp., Carduus spp., Tanacetum vulgare L., Cirsium spp., Taraxacum officinale (L.) Weber ex F.H. Wigg., Knautia arvensis (L.) Coult., Solidago spp., Hypochoeris radicata Cabrera, Centaurea spp., Acer platanoides L., Anchusa officinalis L., Vicia spp., Ranunculus spp., Cota tinctoria (L.) J. Gay, Epilobium angustifolium L., Helianthus annuus L., Rubus spp., Angelica sylvestris L., Geranium palustre L., Valeriana officinalis L., Thymus serpyllum L., Jasione montana L., Veronica longifolia L. (Ruszkowski, 1998; Šima & Smetana, 2012). All plant species visited by this bumblebee have saucer-shaped or globular flowers with easily accessible nectaries.

The aim of the study is to present the current distribution of B. semenoviellus in Poland and an effort to identify conducive factors for the dispersion of the species.

Our survey was based on specimens observed in the 20^th and 21^st centuries in Poland. We compiled data from publications, internet databases and personal communications. Materials collected by Pawlikowski up to the year 2000 in “A Distribution Atlas of Bumblebees in Poland” (2008) were also developed and those by Rasmont et al. (2015) in Europe were also used. Observations were also made with the participation of numerous volunteers as a part of photographic monitoring of pollinating insects, organized on blogs belonging to the Biomonitoring Laboratory of Land Environment of the Nicolaus Copernicus University in Toruń and the Natura i Człowiek Association. The collected data were presented on a map including the UTM grid, while the chronology of the species observation was maintained.

In determining the species from the photographs, it was considered that the colour features of Bombus semenoviellus should not be confused with the common B. hortorum, or the less common B. ruderatus or B. jonellus. The first two species are long-tongued bumblebees which visit flowers with long corolla, while the short-tongued B. jonellus does not have pale hairs on the face or on pollen baskets.

Records from the literature (Kosior & Płonka 2003; Banaszak, Ratyńska, & Banaszak, 2004; Banaszak et al., 2006; Banaszak & Motyka, 2007; Kosior et al., 2008; Kowalczyk & Kurzac, 2008; Pawlikowski, 2008; Banaszak & Jaroszewicz, 2009; Banaszak & Ratyńska, 2014; Banaszak, 2016; Banaszak & Ratyńska, 2016) Q=queen, W=worker, M=male, ex.=extend material:

Magdalenowo [FE39] 20 VIII 1988 - 1 W, leg. A. Krzysztofiak

New records:

Miłachowo Reserve [XV43] 2001 - 1 ex., author’s coll., leg. J.K. Kowalczyk

Bumblebees most often occur in temperate and cold climate regions and in mountainous areas (Williams, 1998), which are the most exposed to climate change. Climate warming is predicted to reduce the ranges of occurrence of most bumblebee species and to change the structure of their functioning (Rasmont et al., 2015) including access to host plants (Memmott et al., 2007). On the other hand, the expansion of some bumblebee species into new areas has been observed (MacDonald, 2001). Data on distribution and occurrence in new habitats can lead to important conclusions about the ecological plasticity of bumblebees and the possibilities of adaptation in the context of ongoing changes.

Despite all scenarios showing that the area of this species’ occurrence is decreasing due to global warming (Rasmont et al., 2015), B. semenoviellus has been confirmed to be increasing its range in Finland in the 1960s (Elfving, 1965), in Lithuania (Monsevičius, 1993) and in Poland in the 1980s (Pawlikowski, 2008). Currently, it is probably dispersed throughout the whole country but is rarely found (Banaszak, 2006; Banaszak et al., 2006; Kosior et al., 2008; Pawlikowski, 2008; Banaszak, 2009; Pawlikowski & Pawlikowski, 2012). Its presence has also been confirmed in Germany (Smissen & Rasmont, 2000), Czech Republic (Přidal & Tkalců, 2003), Austria (Streinzer, 2010) and Slovakia (Šima & Smetana, 2012). In Ukraine it has been confirmed only in the 21^st century but probably appeared there much earlier (Konovalova, 2002, 2007). In 2013 it was also recorded in Norway (Ødegaard et al., 2015), and in 2017 in Sweden (Cederberg & Holmström, 2018). Recently, the species has spread further westward towards France and the Benelux countries, as well as in the northern part of the Scandinavian peninsula up to the Arctic Circle (GBIF Secretariat, 2017). Now Hesse, Germany is the most western locality of its entire range (Frommer, 2018).

Current reports from Poland indicate new locations and their dispersal, especially in the central part of the country (Fig. 2). A 2018 report from the Polish part of the Tatra Mountains, at an altitude of 1050 m a.s.l., and 2019 from Mt. Śnieżka of the Giant Mountains at an maximum altitude of 1603 m a.s.l. indicate the existence of suitable habitats in high mountains, which can be argued because of climate change. This species could have appeared earlier in the Polish Tatras and then spread to the Slovakian side, where it was recorded in 2011 (Šima & Smetana, 2012). Such an expansion in the high mountains demonstrates the ecological plasticity of the species.

Fig. 2

The increase of continentalism in Europe is also likely to affect the current status of the species expansiveness. Three species of bumblebees from the Siberian parts of Eurasia: B. hypnorum, B. schrencki and B. semenoviellus are now increasing their prevalence in the west (Rasmont et al., 2015). High differences between temperatures in summer and winter favour those Siberian species. Also of interest, many specimens of B. semenoviellus have been found on plants originating from its native central and west Asia. Those plants also occurring in eastern and central Europe could have helped this bumblebee spread west throughout Europe (Tab. 1).

It is possible that this species will further increase its distribution range towards Western Europe. Based on the observations made so far, it is not possible to determine its invasive features and increased competitiveness for food and nesting places in relation to other bumblebee species. However, B. semenovielluss expansion should still be monitored, and the knowledge about its life needs should be gradually supplemented.