Stelidota geminata (Say, 1825)

Stelidota geminata (Say, 1825)

Material examined: Sakar Mts, Ustrem Vill., 42°01.341’N 26°27.385’E, 95 m a.s.l., backyard of a house ( Fig. 1 B, D), 09.ix.2024, 1 ♀ ( BFUS- COL000010 ), in soil under decaying figs, D. Gradinarov & Y. Petrova leg. ( Fig. 2 D) GoogleMaps .

According to Jelínek et al. (2016) S. geminata originated from Southern USA and has been introduced in Italy at the end of the 20th century, rapidly expanding its range in continental Europe. In the USA, this species is considered a serious pest of strawberries, but it is also known to develop on other fruits and vegetables ( Jelínek et al. 2016; Martynov et al. 2019; Zhekova 2020). In Bulgaria, the species is firstly reported by Guéorguiev (2018) on a single finding with a pitfall trap at Chelopech Village, Sofia Province and subsequently by Zhekova (2020) from Chervena voda Village, Ruse Province. The second author also reports damages on the fruits of the strawberry, apricots and tomatoes, caused by this species ( Zhekova 2020). A single male specimen of S. geminata from Bulgaria (Stara Zagora Province) is also preserved in the BFUS collection, labelled “ Bulgaria: Sarnena Gora Mts, 3 km NW Gorno Novo Selo Vill., 42°28.393’N 25°13.241’E, 800 m a.s.l., oak forest, 22.vii.– 26.viii.2018, pitfall traps, D. Gradinarov & Y. Petrova leg. ( BFUS-COL 000011). It seems that the species is successfully established and presently widespread in Bulgaria.

The alien nitidulid species in our study coexist in distinct microhabitat (decaying figs). Apart of the aforementioned four species, several specimens of Carpophilus , subgenus Myothorax Murray, 1864 , were also obtained from collected fruits (figs and apples) from the same localities. The complicated taxonomy of this subgenus ( de Benedetta et al. 2022; Semeraro et al. 2023), however, does not allow currently their identification to species level. Coexistence of P. picta on decaying dates with two other alien sap beetles in Europe – U. humeralis (Fabricius, 1798) and E. luteola Erichson, 1843 is reported by Viñolas et al. (2014). Montagud & Orrico (2015) report coexistence of P. picta with another alien Phenolia species – P. (L.) tibialis (Boheman, 1851) , on fallen fruits of F. carica and Opuntia sp. , as well as coexistence with unspecified indigenous nitidulids. It appears that the competition for resources (if present) among the frugivorous sap beetle species in these cases is balanced in a way that allows their coexistence in the natural habitats.