The spread of Colletes hederae Schmidt & Westrich, 1993 continues – first records of this plasterer bee species from Slovakia and the Czech Republic

Colletes hederae Schmidt & Westrich, 1993 is a cryptic bee species from the C. succinctus species-group. The previous occurrence and spreading of this species were predominantly in south-western Europe. To determine if the species was spreading in Slovak territory, Hedera helix was monitored from autumn 2015. The ivy-bee was first recorded in Slovakia during autumn 2017. This species is widespread inside and around Bratislava; however, it was not recorded under this study in any sites located eastwards. In the Czech Republic, it was not recorded in the south-east part of the country in 2017–2019. In 2020, the occurrence of this species was confirmed in many localities in the south of the country and strong populations were discovered, especially in the towns Znojmo and Mikulov. The populations likely originated from neighbouring Austria, where this species was discovered in 2006 and the localities are usually less than 100 km away from Czech and Slovak localities. A further survey could map a route of the northwards spread of this species.