Image Credit: Hartmut Wisch
Bee-hornets (Masaridae) – pollenivores – Bee-hornets represent an unsuccessful evolutionary attempt to evolve pollen-exploiting wasps. True bees are derived from the solitary wasps (Sphecidae), but bee-hornets are specialized hornets. Bee-hornets are functional bees with a life style very similar to Hylaeus. Bee-hornets swallow pollen in the flowers they visit and regurgitate it in the nest. They build cells of mud, similar to Osmia and Anthocopa bees, usually on the underside of cliffside talus rocks. There is only 1 genus in the USA, only southwestern, and only 2 species reach Oregon – both are specialist feeders (one on beardtongue (Penstemon), one on wild heliotrope (Phacelia)).
Both sexes resemble yellow-jacket hornets but have very distinctive antennae male antennae are elongate and clubbed at the tip, female antennae are very short and curled. The beardtongue species is the size of a queen, whereas the wild heliotrope species is the size of a worker yellow jacket.