Evidence of vertical migration in the Ipanema bat Pygoderma bilabiatum (Chiroptera: Phyllostomidae: Stenodermatinae)

Carlos E L Esbérard,Marta E Fabián,Fernando Carvalho,Margareth L Sekiama,Pedro H Nobre,Tássia Jordão-Nogueira,Artur Stanke Sobrinho,Daniela Dias,Isaac P De Lima,Sérgio L Althoff

doi:10.1590/s1984-46702011000600004

Abstract

Migration is defined as a seasonal and cyclic population movement observed in all animal classes and studied mainly in vertebrates. A considerable part of the knowledge on migration comes from birds, for which migration is an important aspect of their biology. In the case of bats, females usually migrate larger distances than males in some species. The present study analyzes the seasonal occurrence of Pygoderma bilabiatum (Wagner, 1843) at different elevations, in order to test for a pattern that evidences migration, using data from the states of Espirito Santo, Minas Gerais, Rio de Janeiro, Sao Paulo, Parana, Santa Catarina, and Rio Grande do Sul, Brazil. A total of 529 specimens of P. bilabiatum were captured. Pygoderma bilabiatum seems to be more frequent at intermediate and high elevations (over 80% of all captures were made above 250 m a.s.l.) and at latitudes above 22°S, where rainfall is high (over 1,500 mm) and temperatures are mild (16-23°C). Sex ratio varied with elevation; it was skewed towards males at lower elevations (N = 9, r2 = 0.60, F = 12.311, p = 0.008, Sex ratio = 0.0004*elevation + 0.976), though females predominated at all altitudinal bands and in all states analyzed.

Highlights

Departamento de Zoologia, Universidade Federal do Rio Grande do Sul
A considerable part of the knowledge on migration comes from birds, for which migration is an important aspect of their biology
In Espírito Santo, three individuals were captured in July and August 2005: two males and one female

Summary

Introduction

Departamento de Zoologia, Universidade Federal do Rio Grande do Sul. Avenida Bento Gonçalves 9500, 91501-970 Porto Alegre, RS, Brazil. Migration is defined as a seasonal and cyclic population movement observed in all animal classes and studied mainly in vertebrates. A considerable part of the knowledge on migration comes from birds, for which migration is an important aspect of their biology. In the case of bats, females usually migrate larger distances than males in some species. Rio de Janeiro, São Paulo, Paraná, Santa Catarina, and Rio Grande do Sul, Brazil. Migration is defined as a seasonal and cyclic population movement (ALERSTAM & HEDENSTRÖM 1998) observed in all animal classes and studied mainly in vertebrates. A considerable part of the knowledge on migration comes from birds, for which migration is an important aspect of their biology (BISSON et al.2009). Females usually migrate larger distances than males (FLEMING & EBY 2003). Migratory movements may not occur in all populations of a species (MCCRAKEN et al.1994, RUSSEL et al 2005)

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