Chrysothamnus-nauseosus
Guides
Lordotus pulchrissimus
desert bee fly
Lordotus pulchrissimus is a bee fly in the family Bombyliidae, commonly known as the desert bee fly. Males and females exhibit strong sexual dimorphism in size, fur density, and coloration—females are smaller (2–14 mm), more densely furred, and display brighter orange-yellow tones that fade rapidly with age, while males are larger (8–16 mm), less hairy, and possess black markings on the femora. The species is notable for the daily aerial swarming behavior of males, which form aggregations over stabilized dunes for reasons that remain unclear; this behavior is energetically costly and occurs independently of female presence or resource density. Adults feed primarily on nectar from desert brush, particularly rabbitbrush (Chrysothamnus nauseosus), and serve as pollinators. Larvae are parasitoids, though specific host insects remain unidentified.