Bees of the genera Peponapis and Xenoglossa gather pollen exclusively from species of Cucurbita (squashes, gourds, pumpkins) and are represented in America north of Mexico by 11 species. The results of this study indicate that these bees are important and efficient pollinators. Since they are active before or shortly after sunrise, their role in the pollination of early morning flowering cucurbits has been poorly understood and scarcely appreciated. Nearly all species in the United States collect pollen from domestic as well as native species of Cucurbita, and in some instances their original distribution has been significantly altered following the development and introduction of domestic squashes by aboriginal man. The restriction of some of these bees to the pollen of certain species of Cucurbita suggests that the indigenous Cucurbita foetidissima may be involved in some way with the development of the domestic varieties by primitive man.
