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Sex-based differences in density-dependent sociality: an experiment with a gregarious ungulate
E Vander Wal1, H Yip, P D McLoughlin
1Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada. eric.vanderwal@usask.ca
Ecology
|April 11, 2012
Summary
Male and female elk show different social responses to population density. Males increase social interactions, while females’ interactions initially rise then fall, impacting disease spread models.
Area of Science:
- Animal behavior
- Sociobiology
- Population dynamics
Background:
- Limited empirical data exists on how sociality changes with conspecific density in natural settings.
- Understanding density dependence is crucial for sexual selection and disease transmission models.
Purpose of the Study:
- To investigate sex-specific responses in elk sociality (interaction rate and duration) to manipulated population densities.
- To explore the implications of density-dependent social behavior on sociobiology and disease management.
Main Methods:
- Sex-stratified experiments were conducted on elk in enclosures.
- Proximity-logging radio collars tracked dyadic interactions (frequency and duration) within 1.4 meters.
- Population density was experimentally manipulated.
Main Results:
- Male elk increased their interaction rate with increasing density.
- Female elk interaction rates initially increased then declined at higher densities.
- Male interaction duration decreased with increased density, while female interaction duration peaked at medium densities.
Conclusions:
- A sexually dichotomous, density-dependent social response was observed in elk.
- Findings advance understanding of sociobiology, particularly time constraints on social interactions.
- Results have implications for managing communicable diseases in gregarious wildlife and livestock.
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