Facultative nectarivory is a rare diet strategy in temperate-zone bat species, which almost universally retain ancestral insectivorous feeding habits. In 2005-2007, we discovered that the pallid bat (Antrozous pallidus), a common desert bat, routinely feeds on nectar in the bat-adapted flowers of the cardon cactus (Pachycereus pringleii) in Baja California, Mexico. We study the ecology and evolution of this novel foraging behavior and compare the habits of this facultative nectar-feeding to obligate nectar-feeding by the endangered lesser-long nosed bat (Leptonycteris yerbabuenae).
Lesser-long nosed bats are the primary pollinator of the cardon and occur sympatrically in most parts of Baja with nectar-feeding pallid bats. This system provides a great opportunity to ask questions about the physiological consequences of a generalist diet strategy as well as explore the coevolutionary consequences of facultative and obligate nectar-feeding pollinator behaviors to plant reproductive success.