Facultative Nectar-feeding Behavior in a Gleaning Insectivorous Bat (Antrozous pallidus)

摘要

Foraging plasticity that includes facultative nectarivory is extremely rare in temperate insectivorous bats. We investigated flower-visiting behavior of pallid bats (Antrozous pallidus, Vespertilionidae) to bat-adapted flowers of cardon cacti (Pachycereus pringlei) to determine whether pallid bats consume floral nectar or visit flowers to opportunistically glean insects attracted to flowers. In 2007 and 2008, we recorded flower-visiting behavior of bats using infrared videography on 143 cactus-nights across 14 sites in Baja California, Mexico. Pallid bats were regular visitors to cardon flowers and consumed floral nectar by plunging their faces into the corolla to lap pooled nectar. We recorded 1,198 flower visits by A. pallidus, which accounted for 10% of visits to flowers by all bats. Pallid bats visited flowers on 57% of cactus-night observations (n = 81/143) and 52% (n = 28/54) of captured bats had visible pollen loads. Flower-visiting activity by A. pallidus was concentrated early in the evening where nectarivorous Mexican lesser long-nosed bats (Leptonycteris yerbabuenae [= curasoae], Phyllostomidae) were present, but more evenly distributed throughout the night at sites without L. yerbabuenae, suggesting potential competitive exclusion among these nocturnal chiropteran pollinators.