Ptilothrix is a genus within the tribe Emphorini of the family Apidae (bumblebees, euglossines, honeybees, stingless bees).

These bees have especially prominent hairs in the scopae of their hind legs, to help gather pollen to provision their nests.

Unlike honeybees or other eusocial bee species, the members of Ptilothrix do not form a hive or have division of labor of individuals.

Females nest individually in hard-packed soil and oviposit eggs into brood cells provisioned with masses of pollen and nectar, which provide nutrients for their offspring.

Predation in the larval stage is most commonly from parasitoid wasps, fire ants, and assassin flies, whose life cycles are synchronized with P.

The coarse and long-haired scopae of the genus Ptilothrix aid them in collecting large-grained pollen, such as is found in the family Malvaceae.

The female bee then digs a single-celled or multi-celled burrow, and lines the interior with wax or feces for support.

[4] A comprehensive comparison of nest construction and behavior between species can be found in Rust (1980)[4] and Martins et al.

[9] In some cases, generalist Bombus species are more effective pollinators of Malvaceae flowers than the specialist P. bombiformis.

Also, it may not be in the specialist's best interest to be an efficient pollinator, since they typically want to provision as much pollen as possible in their nests and not lose it brushing up against a flower.