THE NESTING AND FORAGING BEHAVIOR OF PERDITA-TEXANA (CRESSON) (HYMENOPTERA, ANDRENIDAE)

Perdita (Macrotera) texana is a ground nesting, univoltine, facultatively communal bee species found in western Texas and southern Oklahoma. As many as 28 females may share a single nest, but most nests have no more than five females and approximately 25% of the nests are occupied by a single female. Most nests are constructed de novo each year but some females reuse their natal nests. These is no apparent reproductive division of labor among nestmates, as all residents of communal nests forage and have developed ovaries. Nests consist of a single main tunnel and several laterals leading to brood cells. Females provision a single cell per day with pollen and nectar collected exclusively from Opuntia (Platyopuntia) spp. All evidence indicates that P. texana is a successful pollinator of Opuntia. Cell provisioning requires an average of 8 pollen trips and occasionally an additional nectar-only trip. Pollen trips average 6 min, while nectar trips average 17 min. The entire cell-provisioning process requires 72 min on average. P. texana is unusual among bees in that males are regular occupants within nests. Males enter nests throughout the afternoon and reside there until the following morning, leaving just prior to the beginning of cell provisioning by females. The biology of P. texana is compared to that of other Perdita species, and the evolutionary implications of communal nesting are discussed.