differences in diet affect interactions between workers of different crazy ant colonies?
and 4) Can the diet of crazy ants affect antagonistic interactions with fire ants? Question
three examines whether crazy ant Unicoloniality can be affected by diet, while questions
one, two, and four focus on whether fire ants may provide biotic resistance to further
crazy ant colonization and spread. Together, the answers to these questions could have
important implications for the future of the crazy ant introduction.
Methods
All colonies OfRasberry crazy ants used in aggression assays were collected in
Pearland, TX (29.55oN, 95.28oW) on May 24 and May 31,2008. Though 24 distinct
nests were collected, because crazy ants at this site display no aggression between nests,
it is likely that all nests are part of a large supercolony (Holldobler and Wilson 1990).
Fire ant colonies were collected from Katy, TX (29.930N, 95.940W) in early May 2008.
Colonies of both species were polygynous. In order to separate ants from the nesting
material with which they were collected, we flooded colonies and then transferred all ants
to 24cm x 1 Icm plastic nest boxes. Nest boxes were ringed with a thin layer of
Tanglefoot (Tanglefoot, Grand Rapids, Michigan, USA) near the top of the inside walls
in order to prevent escapes.
The initial diet administered to both crazy ant and fire ant colonies consisted of
freezer-killed mealworms and sugar water. This diet was maintained until July 18,2008,
when all food was removed from the crazy ant nest boxes and diet manipulations began.
Each of the 24 crazy ant colonies was assigned to one of four treatments: cricket∕high
sugar, cricket∕low sugar, wax worm∕high sugar, or wax worm∕low sugar, such that there
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