Species of the Week

EDI Species of the Week: Cactus Chimney Bee (Diadasia australis) 🐝🌵

The Cactus Chimney Bee is a small to medium-sized, golden-colored native bee found visiting opuntia and cholla cactus flowers from April to June. Like most of California's native bees, it is a solitary bee, meaning unlike honeybees, it does not form colonies or share a hive. Instead, females nest independently, selecting patches of bare soil to construct small mud chimneys at the entrance of their underground nests, where they overwinter. When spring arrives and females begin to emerge, males gather by the thousands near these nest sites, forming dense clusters known as "mating balls,” waiting for their chance to mate. The Cactus Chimney Bee collects pollen almost exclusively from cacti, making it one of the most important pollinators for cactus flowers in our region. Without it, many of the cacti we associate with Southern California's landscape would struggle to reproduce.