Morphology and flight manoeuvrability in New World leaf-nosed bats (Chiroptera: Phyllostomidae)

Abstract

The relationship between wing morphology and ability to manoeuvre through an obstacle course was examined in five species of bats in the Neotropical family Phyllostomidae. These species represent a range of morphologies and feeding adaptations: Tonatia silvicola, a surface-gleaning insectivore; Artibeus jamaicensis and A. literatus, canopy frugivores; and Carollia perspicillata and C. castanea, understory frugivores. Bats of known morphology were presented with three different obstacle arrangements chosen in random order. In order to control for wing span, spacing between obstacles was scaled to the wing span of the individual (1×, 0.75×, 0.5× the wing span of the bat). Performance was measured as the number of times a bat hit an obstacle hard enough to deflect it. Morphological variables were analysed using principal components analysis and were summarized by the first two principal components (PC): PC 1, ‘size’, with which size-related variables were strongly, positively correlated; PC 2, ‘camber’, on which variables associated with maximum depth of wing camber weighted most heavily. Obstacle course performance was significantly correlated with both size and camber at all obstacle spacings: larger bats hit more obstacles, even though obstacle spacing was scaled to wing span, and bats with better ability to camber wings hit fewer obstacles. These results show that bat species that forage in more cluttered habitats are more likely to be small in size and/or have wings able to produce the high camber necessary to maintain lift at low flight speeds.