Megachile sculpturalis F. Smith, 1853

Gradinarov, Denis, Petrova, Yana & Ljubomirov, Toshko, 2023, Nesting observation of the Sculptured Resin bee Megachile sculpturalis F. Smith, 1853 (Hymenoptera: Megachilidae) in Bulgaria, ZooNotes 2023 (229), pp. 1-4 : 2-3

Megachile sculpturalis F. Smith, 1853 ( Figs. 2 , 3 )

Material examined: Bulgaria, Banitsa Vill., 43°20'19.3"N 23°41'06.4"E, 276 m a.s.l., 19.vii.2023, 1 ♀, on the ground, T. Ljubomirov leg. ( IBER) ; Bulgaria, Varna City, Sea Garden , 43°12'09.9"N 27°55'19.4"E, 14 m a.s.l. (site 1), 18.viii.2023, 2 ♀♀, on trunk of S. japonicum, D. Gradinarov leg. ( BFUS) .

Only two specimens from site 1 of the Sea Garden of Varna City were collected, but on the 17 th and 18 th of August , on the same tree, we observed 3 to 4 females simultaneously entering different holes in the bark. In proximity, at site 2 (43°12'17.8"N 27°55'25.3"E, 22 m a.s.l.), on the 19 th and 20 th of August several females were observed and photographed ( Fig. 3 ). At both sites, the bees exhibited the same behavior pattern: repeated entering – exiting nesting holes and fetching materials in their mandibles inside (probably for a nest). The other observations include crawling on the tree trunk near the hole openings and sideways, as well as alight and crawl on polypore fungi on the same tree .

Our data indicates that the species is established in Bulgaria, including the east of the country. It is desirable to obtain more data of the species distribution in Bulgaria as well as of its preferences for plant species and nesting sites. The current records of its presence in the country concern only urban or rural areas and it is important to observe if it invades the natural ecosystems.

According to Russo (2016) the potential negative impact of M. sculpturalis consists of the competition for nesting sites, the pollination of invasive weeds, and the associated alteration of the resident pollination networks ( Russo 2016). In particular, M. sculpturalis can occupy active nests of species of the genera Xylocopa Latreille, 1802 , Osmia Panzer, 1806 as well as of Isodontia mexicana (de Saussure, 1867) ( Laport & Minckley 2012; Le Féon & Geslin 2018).

Figures

Fig. 2. Megachile sculpturalis female, Bulgaria, Varna City, 18.viii.2023.

Fig. 3. Females at the nest entrance on the trunk of Styphnolobium japonicum in Sea Garden of Varna City, Bulgaria (site 2). A – 19.viii.2023, 20:00 p.m.; B – 20.viii.2023, 08:50 a.m.