The adaptive value of aggregation among juvenile Caribbean spiny lobster: An evaluation using individual-based modeling
Authored by III Thomas W Dolan, Mark J Butler
Date Published: 2006
DOI: 10.1651/s-2742.1
Sponsors:
United States National Oceanic and Atmospheric Administration (NOAA)
United States National Science Foundation (NSF)
Platforms:
Fortran
Model Documentation:
Other Narrative
Mathematical description
Model Code URLs:
Model code not found
Abstract
Ontogenetic changes in gregariousness by pre-reproductive animals, like
that observed in juvenile Caribbean spiny lobsters (Panulirus argus), may be adaptive and reflect size-specific changes in the effectiveness
of aggregation in promoting survival. Alternatively, aggregation may
simply result from changes in the distribution or availability of
suitable habitat structure, or from other behaviors that enhance
survival. There are currently two hypotheses explaining the potential
benefits of gregarious behavior in juvenile spiny lobsters, both of
which focus on increasing survivorship by reducing predation pressure:
the group benefit hypothesis and the guide hypothesis. The group benefit
hypothesis argues that aggregations of juvenile lobsters reduce
individual susceptibility to predators because groups are better able to
fend off attackers or benefit by dilution of risk. The guide hypothesis
suggests that aggregation is a consequence of shelter seeking behavior, in which individuals searching for shelter follow conspecific odors, thus reducing the time they spend in the open exposed to higher
predation rates. The guide mechanism should be most effective in areas
of low shelter density. We used an individual-based, spatially-explicit
model describing recruitment of juvenile spiny lobster in the Florida
Keys to compare behavioral models incorporating a guide effect and group
benefit under conditions of high and low shelter densities. We found
that the guide effect significantly enhanced survival only under the
most extreme circumstances where shelter was scarce, the risk of
predation highest, and the effective distance of the guide effect
strongest. In contrast, small increases in direct group benefit led to
significantly higher population abundances under a wide range of
conditions.
Tags
Predation
habitat
New-zealand
Social-behavior
Rock lobster
Jasus-edwardsii
Florida bay
Panulirus-argus latreille
Shelter-size
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