with which they were collected by flooding the nests, each colony was placed in a 24cm
x 1 Icm plastic nest box. To prevent ants from escaping, nest boxes were ringed with a
thin layer of Tanglefoot (Tanglefoot, Grand Rapids, Michigan, USA) near the top of the
inside walls. Each colony was fed a standard diet of sugar water daily and half of a
freezer-killed mealworm (Armstrong’s Cricket Farm, West Monroe, LA) every other day.
In order to obtain colonies of uniform size for competitive pairings, field-collected
colonies were divided into smaller units from June 18 to July 1,2008. Each unit
contained one queen, no brood, and either 1000 workers in colonies matched by worker
number or 500 mg of workers in colonies matched by biomass. Because counting
individual workers was not feasible, we used an average per worker mass to extrapolate
the mass of 1000 workers. For crazy ants, we randomly selected and weighed between
16 and 26 workers from each of 10 different colonies, recording the number of workers
and the total weight each time. For fire ants, we repeated this process with 22 to 28
workers from each of 13 different colonies. The average weight per Rasberry crazy ant
was 0.68mg, and the average weight per fire ant was 1.43mg. Therefore for colonies that
were matched by worker number, we used 680.0 ÷ 50.0mg of crazy ants or 1430.0 ±
100.0mg of fire ants.
In total, we created 16 units of crazy ants with 500mg of workers, 16 units of
crazy ants with 1000 workers, 15 units of fire ants with 500mg of workers, and 16 units
of fire ants with 1000 workers. These colony units were haphazardly assigned to a
treatment of either control or competition such that there were 8 control colony units of
crazy ants standardized by biomass, 8 control colony units of crazy ants standardized by
worker number, 7 control colony units of fire ants standardized by biomass, 8 control
40