The Australian bee <i>Hylaeus</i> ( <i>Gnathoprosopis</i> ) <i>euxanthus</i> (Hymenoptera: Colletidae) in Argentina: Nesting biology, floral preferences and parasitism

Abstract This study reports the first confirmed occurrence of the Australian bee Hylaeus ( Gnathoprosopis ) euxanthus (Cockerell) in Argentina. The identification is supported by collected specimens reared from trap nests and photographic records from the iNaturalist platform. Observations on nesting behaviour, pollen provisioning and associated parasitoids are presented. Pollen analysis of brood cells revealed a preference for exotic Myrtaceae species. The study also records an endoparasitoid, Coelopencyrtus hylaei Burks (Encyrtidae). These findings highlight the importance of citizen science in detecting alien bee species.