The New Mexico Rare Arthropod Resource

Bombus flavidus is a parasitic bumblebee, known for its cuckoo-like behavior, and lacking a corbicula for pollen collection. Rather than establishing its own colonies, it invades the nests of other bumblebee species (primarily in the subgenus Pyrobombus). Having no workers of its own, B. flavidus instead relying on other species, notably B. rufocinctus, B. occidentalis, and B. appositus, for worker bees to rear its young (Goulson 2010). It is widespread and most similar to B. insularis and B. suckleyi, but distinctly has a curled under abdominal tip that forms a small spine (Williams et al., 2014). B. flavidus is a smaller bodied bumblebee species with predominantly black and yellow hairs that can present with some regional variety. They consistently have black facial hair, the thorax is often predominantly yellow with a black spot, but has also been seen with yellow shoulders and an almost entirely black thorax. T2 of the abdomen is always black and T4 is always yellow/white (Williams et al., 2014). Males can be identified by orange hairs on the tip of their abdomens. The few observations of B. flavidus in New Mexico share majority black abdomens and distinguished black haired portions of the thorax (iNaturalist 2025).