Interaction of vestibular, echolocation, and visual modalities guiding flight by the big brown bat, Eptesicus fuscus

Abstract

The big brown bat (Eptesicus fuscus) is an aerial-feeding insectivorous species that relies on echolocation to avoid obstacles and to detect flying insects. Spatial perception in the dark using echolocation challenges the vestibular system to function without substantial visual input for orientation. IR thermal video recordings show the complexity of bat flights in the field and suggest a highly dynamic role for the vestibular system in orientation and flight control. To examine this role, we carried out laboratory studies of flight behavior under illuminated and dark conditions in both static and rotating obstacle tests while administering heavy water (D2O) to impair vestibular inputs. Eptesicus carried out complex maneuvers through both fixed arrays of wires and a rotating obstacle array using both vision and echolocation, or when guided by echolocation alone. When treated with D2O in combination with lack of visual cues, bats showed considerable decrements in performance. These data indicate that big brown bats use both vision and echolocation to provide spatial registration for head position information generated by the vestibular system.

Questions, ideas and tools: lessons from bat echolocation

“…Inverting the audiograms (b) and considering hearing thresholds, illustrates the distances at which different echolocation calls would be detected by these moths and how initial call intensity affects distance of detection (reprinted with permission from Fenton & Fullard 1979). acquired from vision and echolocation (e.g. Horowitz et al 2004), but for most species we lack details about how vision and echolocation interact. At least some species of nectar-feeding bats see in the ultraviolet spectrum (Winter et al 2003;Muller et al 2009), but the significance of this ability remains relatively unstudied.…”

Somatosensory Substrates of Flight Control in Bats

“…The contribution of hearing and vision to bat flight behaviors is established (Horowitz et al, 2004; Simmons et al, 1979); however, the role of touch has been largely overlooked since the discovery of echolocation (Chadha et al, 2011; Sterbing-D’Angelo et al, 2011; Zook, 2006). As bats flap their wings, they produce complex aerodynamic trails (Hedenstrom et al, 2007; Hubel et al, 2010).…”

The Evolution of Bat Vestibular Systems in the Face of Potential Antagonistic Selection Pressures for Flight and Echolocation

“…Current phylogenetic and fossil evidence suggest that powered flight evolved before echolocation in bats, but whether or not echolocation evolved more than once or was lost by non-echolocating Old World fruit bats (Pteropodidae), is unresolved [34]–[37]. Previous studies on bat vestibular systems have considered single species and thus provide few clues into the effects and origins of echolocation [38]–[40].…”