Correlation of skull morphology and bite force in a bird-eating bat (Ia io; Vespertilionidae)

Biye Shi; Yuze Wang; Lixin Gong; Yang Chang; Tong Liu; Xin Zhao; Aiqing Lin; Jiang Feng; Tinglei Jiang

doi:10.1186/s12983-020-00354-0

Correlation of skull morphology and bite force in a bird-eating bat (Ia io; Vespertilionidae)

Front Zool. 2020 Mar 19:17:8. doi: 10.1186/s12983-020-00354-0. eCollection 2020.

Authors

Biye Shi^#^{1

2}, Yuze Wang^#^{1

2}, Lixin Gong^{1

2}, Yang Chang^{1

2}, Tong Liu^{1

2}, Xin Zhao^{1

2}, Aiqing Lin^{1

2}, Jiang Feng^{1

2

3}, Tinglei Jiang^{1

2}

Affiliations

¹ 1Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, 2555 Jingyue Street, Changchun, 130117 China.
² 2Key Laboratory of Vegetation Ecology of Education Ministry, Institute of Grassland Science, Northeast Normal University, 2555 Jingyue Street, Changchun, 130117 China.
³ 3College of Life Science, Jilin Agricultural University, 2888 Xincheng Street, Changchun, 130118 China.

^# Contributed equally.

Abstract

Background: Genetic and ecological factors influence morphology, and morphology is compatible with function. The morphology and bite performance of skulls of bats show a number of characteristic feeding adaptations. The great evening bat, Ia io (Thomas, 1902), eats both insects and birds (Thabah et al. J Mammal 88: 728-735, 2007), and as such, it is considered to represent a case of dietary niche expansion from insects to birds. How the skull morphology or bite force in I. io are related to the expanded diet (that is, birds) remains unknown. We used three-dimensional (3D) geometry of the skulls and measurements of bite force and diets from I. io and 13 other species of sympatric or closely related bat species to investigate the characteristics and the correlation of skull morphology and bite force to diets.

Results: Significant differences in skull morphology and bite force among species and diets were observed in this study. Similar to the carnivorous bats, bird-eaters (I. io) differed significantly from insectivorous bats; I. io had a larger skull size, taller crania, wider zygomatic arches, shorter but robust mandibles, and larger bite force than the insectivores. The skull morphology of bats was significantly associated with bite force whether controlling for phylogeny or not, but no significant correlations were found between diets and the skulls, or between diets and residual bite force, after controlling for phylogeny.

Conclusions: These results indicated that skull morphology was independent of diet, and phylogeny had a greater impact on skull morphology than diet in these species. The changes in skull size and morphology have led to variation in bite force, and finally different bat species feeding on different foods. In conclusion, I. io has a larger skull size, robust mandibles, shortened dentitions, longer coronoid processes, expanded angular processes, low condyles, and taller cranial sagittal crests, and wider zygomatic arches that provide this species with mechanical advantages; their greater bite force may help them use larger and hard-bodied birds as a dietary component.

Keywords: 3D geometric morphometrics; Bird-eating bats; Bite force; Diets; Phylogeny; Skull.