Does Bergmann’s rule apply in bats? Evidence from two neotropical species

ABSTRACT

Bergmann’s rule is one of the most vigorously debated ecogeographic patterns but has rarely been examined in Neotropical bats. Herein, I examined Bergmann’s rule in Carollia perspicillata and Artibeus lituratus along an elevation gradient of 2500 m at both inter- and intraspecific level. I measured 384 specimens from collections belonged to C. perspicillata (89 ♀, 102 ♂) and A. lituratus (89 ♀, 104 ♂). The size of C. perspicillata increased with increasing elevation and decreasing temperature, whereas A. lituratus showed the converse pattern. For both species, females did not differ between elevation categories, contrary to males that were larger above 1000 m in C. perspicillata, but smaller in A. lituratus. Conformity to Bergmann’s rule depends on bat size and sex. Despite C. perspicillata follows the pattern, the explanatory mechanisms still need to be understood. By contrast, A. lituratus follows the converse of Bergmann’s rule due to naked and highly vascularized wings that aid thermoregulation in warmer environments. Male size is more sensitive to changes in temperature for both species which may be partially explained by sexual selection. Elevation and temperature are not the only factors related to bat morphology and other mechanisms may explain size in bats.

KEYWORDS:

• biogeography
• body size
• chiroptera
• Colombia
• environmental gradient

Acknowledgments

I am very grateful to Jairo Pérez-Torres, the curator of the Mammalian Collection of Museo Javeriano de Historia Natural from Pontificia Universidad Javeriana (Bogotá, Colombia), for allowed me to access the specimens of the Collection. All my gratitude also goes to Laura L. Garzón-Salamanca for the elaboration of the map (Figure 2) and to Diego Soler for his help with the obtention of environmental variables and for his comments and insightful ideas in data analysis and discussion. Finally, I want to thank to the two reviewers and the editor for the comments and suggestions that improved the quality of this manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Notes

1. Data availability statement: All data associated with this study are available from the Open Science Framework (OSF) repository: https://osf.io/y6ct7/

Additional information

Funding

The author has no funding to report.