Andrena tarsata Nylander 1848

Andrena tarsata Nylander, 1848 Conservation status EN Distribution This species is found across most of Europe, and as far east as China (Tomozei 2014). In Belgium, it could be observed in most of the Ardenne before 1950. Since then, observations have been extremely scarce (Pauly 2024). This species is likely threatened by habitat destruction and degradation, although its specific requirements are not fully understood. Efforts should be made to identify and protect aggregations in potential habitats such as sandy heathlands and moors. These focal habitats could also be extended or restored where possible. Notes This species has been reported in meadows, heathlands, and moors situated on sandy soils, where nests are likely to form aggregations, although few observations have been documented (Else 2005, Westrich 2018). Nests are preferentially located on sloped, south-facing surfaces (Else 2005), similar to the quarry where we collected the sole specimen of this species. While Westrich 2018 notes that females collect pollen exclusively from Potentilla flowers, data from England suggest that the species might visit a wider range of species (Else 2005). Adults are typically observed from June to September (Peeters 2012). Diagnosis Another small (<9 mm), dark Andrena not belonging to the Micrandrena subgenus (Fig. 5). Females can be identified thanks to their orange hind tibiae and tarsi which is unique in Belgium for such a small species. Males have a pale clypeus, a short head and dark hairs along the inner eye margin. Their third antennal flagellomere is longer than the subsequent two (Wood 2023).