Meeting Abstract

106.4  Saturday, Jan. 7  How nectar-feeding bats lap: nectar uptake and ingestion in Glossophaga soricina HARPER, C.J.*; SWARTZ, S.M.; BRAINERD, E.L.; Brown University, Providence; Brown University, Providence; Brown University, Providence caroline_harper@brown.edu

In nectar-feeding bats, the tongue tip resembles a brush because it is covered with long filamentous papillae. In Glossophaga soricina, these hairlike papillae are organized in discrete rows on the dorsolateral surface of the tongue tip. The goal of this study is to describe how these hairlike papillae are used to collect nectar during feeding. Live G. soricina (n=3) were trained to feed from a small acrylic feeder and their tongues were filmed with monochrome and color high-speed video cameras. The high-speed videos show that these hairlike papillae are dynamic during feeding. During the initial phases of tongue protrusion, the papillae are proximally oriented and lie flat against the tongue. As the tongue tip enters the nectar, the hairlike papillae become engorged with blood and project from the tongue’s surface. In their erect state, the papillae extend perpendicular to the long axis of the tongue and nectar is trapped between the rows of papillae. The hairlike papillae remain in their erect posture throughout tongue retraction and nectar is carried into the mouth for ingestion. These observations provide the first evidence for a hemodynamically-powered specialization of the tongue. Nectarivores have been noted for their specialized feeding adaptations, such as the fluid trap recently described in hummingbirds. The novel fluid capture system in nectar-feeding bats described here, however, is different from that of hummingbirds because the papillae are actively controlled by blood flow and do not rely on passive tongue-fluid interactions.