Productivity in a Neotropical social wasp, Polybia occidentalis: per capita output decreases with swarm size
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Authors
Kramer, Kory R.
Issue Date
1999
Type
Thesis
Language
en_US
Keywords
Alternative Title
Abstract
Many behavioral ecologists are ultimately interested in what factors contribute to
the determination of optimal group size in the social insects. Past studies have shown
that colony efficiency, measured as productivity of nest cells per female, decreases as
colonies increase in size. Other studies have been conducted, however, that have
established results contradictory to the former. As colony efficiency may be an
evolutionarily important aspect in answering the ultimate question of what determines
colony size in social insects, this study was conducted to resolve the present conflict in
previous results.
Polybia occidentalis is an ideal organism to work with in order to better
understand sociality and its evolution in the Hymenoptera Because these wasps establish
a new nest through swarm-founding, colonies can be manipulated in order to reset their
developmental stage to zero. Due to the fact that nests are usually built within 2 m of the
ground, progress of the colony can easily be tracked and final collection of the nest is
almost always possible.
Colonies of Polybia occidentalis were forced to abscond and start new
nests, thus resetting their stage of construction to zero. A census was conducted before
construction of the new nest. Colonies were allowed to develop for 25 days, after which
they were collected. The wasps were counted to give the final population of the colony
and nest cells were counted to give an indication of colony productivity. With these data,
productivity per female (per capita productivity) was calculated for each colony and
regressed against colony size. Per capita productivity decreases with increasing colony
size.
With honors.
With honors.
Description
vi, 38 p.
Citation
Publisher
Kalamazoo College
License
U.S. copyright laws protect this material. Commercial use or distribution of this material is not permitted without prior written permission of the copyright holder.