Abstract
Spix's disc-winged bats, Thyroptera tricolor, roost in young, rolled leaves of Heliconia or Calathea plants. In this paper, we examined how the combination of high habitat availability, low occupancy rate and short longevity of those roosts may affect the pattern of interactions among individuals in the population. We regularly censused a 5.69-ha study area in northeastern Costa Rica and examined patterns of association using mark-recapture data. Thyroptera tricolor formed behaviourally cohesive social groups of mixed sex, ranging in size from four to 14 individuals. Approximately 85% of dyads maintained associations over time periods of up to 100 days, and 40% of dyads maintained longer-term associations of at least 420 days across sex classes. Individuals within social groups did not always roost together, but they shared a small common roosting home range, which averaged just 0.19ha. Members of different social groups rarely associated, although limited associations between members of select social groups in one subunit were observed. However, roosting home ranges of adjacent social groups often overlapped (up to 39% of home ranges, and up to 92% of the area of the smaller home range), and home range centres were situated less than 100m apart. Thus, social groups rarely interacted but overlapped in space. The features of this social system are unique among bats and mammals in general, and point to groupings based on kinship or cooperation.
| Original language | English |
|---|---|
| Pages (from-to) | 507-521 |
| Number of pages | 15 |
| Journal | Animal Behaviour |
| Volume | 68 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - Sept 2004 |
Bibliographical note
Funding Information:This research was supported by an NSERC research grant to M.B.F., by York University and by the American Museum of Natural History Theodore Roosevelt Memorial Fund. We thank S. Bouchard, B. Forester, S. Gill, R. James, L. Kruse, D. Riskin, J. Unger, numerous short-term volunteers and especially D. Dechmann and M. Knörnschild for their valuable help in the field. We also thank the Canadian Organization for Tropical Education and Research and their staff at the Caño Palma Biological Station, in particular R. Ballard and R. James, for logistical support, and the Ministerio de Recursos Naturales, Energia y Minas for permission to work in Costa Rica. S. Hamilton, T. Martin, C. Popplewell and A. Sanchez kindly provided assistance with the preparation of maps, and M. Engstrom, S. Gill, B. Loughton, B. Stuchbury, N. Yan and three anonymous referees provided valuable comments on earlier versions of this manuscript. M.J.V. was supported by an NSERC Postgraduate Scholarship, an Ontario Graduate Scholarship, an Ontario Graduate Scholarship in Science and Technology, and a York University President's Dissertation Scholarship.
ASJC Scopus Subject Areas
- Ecology, Evolution, Behavior and Systematics
- Animal Science and Zoology