Eucera nigrescens Perez 1880

Eucera nigrescens Pérez, 1880 Conservation status EN Distribution Its population in Belgium has declined around 50 % to 80 % between 1900-1969 and 1970-2017, with severely fragmented populations (Drossart 2019). Few populations remain in Pays de Herve, Condroz and Plateaux Limoneux Hennuyers (Drossart 2019). The drastic decline of leguminous crops and nutrient-poor grasslands is probably a major driver of this decline. Notes Eucera nigrescens primarily inhabits meadows and grasslands rich in Fabaceae, as these plants are its main foraging source (Standfuss 2009). Females exclusively collect pollen from Fabaceae species, while males are often associated with the orchid Ophrys fuciflora (Gaskett 2010). The single specimen we collected was observed foraging on a Lathyrus species. Diagnosis One of the two Eucera species in Belgium. Compared to E. longicornis, E. nigrescens (Fig. 10) it has a domed and elongated clypeus, and the mesonotum weakly punctuated (Amiet et al. 2007). In males, the mesosoma hair colour varies considerably, ranging from brown to silver, whereas, in females, the variation is more limited, primarily spanning from light to dark brown.