Group size and direct fitness in social queues
Shreeves, G; Field, J
Date: 1 January 2002
Journal
American Naturalist
Publisher
University of Chicago Press
Publisher DOI
Abstract
We explore the effects of group size on the direct reproductive
success of subordinate helpers in eusocial animals where
only a single, dominant individual reproduces at one time. Helpers
can reproduce directly if they inherit dominance, but when dominance
is age based, an individual born into a larger group has a
longer wait to ...
We explore the effects of group size on the direct reproductive
success of subordinate helpers in eusocial animals where
only a single, dominant individual reproduces at one time. Helpers
can reproduce directly if they inherit dominance, but when dominance
is age based, an individual born into a larger group has a
longer wait to inherit. We show that this disincentive to help can
potentially be offset by increased productivity, increased life span,
and insurance-based benefits for helpers if they survive to inherit
dominance in larger groups. We analyze a field experiment in which
group size was manipulated in the hover wasp Liostenogaster flavolineata.
Productivity increased linearly with group size, larger groups
were less likely to fail, and dominants in larger groups may have
lived longer. Combined with the probability of inheriting dominance,
these effects led overall to a negative correlation between group size
and expected direct fitness, mainly because group size decreased during
our study period, so that helpers could not expect to inherit as
large a group as they started queuing in. Our analysis suggests that
the relationship between group size and productivity plays a central
role in determining the fitness consequences of helping
Biosciences - old structure
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