protein than adult workers (Holldobler and Wilson 1990). Ant species did not co-occur
at protein baits, suggesting that protein resources, even when available, may be difficult
to control in the field due to high levels of competition, thus increasing a colony’s need to
recruit in high numbers.
In a field setting, crazy ants discover baits more quickly but fire ants dominate
baits after 1 hour. Thus, in this context, crazy ants would be considered opportunists,
who discover food quickly and exploit it before other ants arrive, while fire ants would be
considered extirpators that aggressively dominate discovered resources (Wilson 1971).
Both species fit the dominance-discovery tradeoff model in the field setting (Fellers
1987). However, in the laboratory experiment, crazy ants discovered baits more quickly
and controlled more baits than fire ants did at the end of the experiment. This finding
suggests that when crazy ant colonies are evenly matched in worker number or biomass
with fire ants, crazy ants may be both the discoverers and the controllers of baits.
Therefore, crazy ants may have a similar community role as Argentine ants, which have
also shown exploitative competitive ability as well as behavioral dominance in part of
their invasive range (Holway 1999). Nevertheless, ant community roles, including those
of opportunists and extirpators, can be context-dependent (Morrison 1996), and our
findings are an example of this phenomenon, as crazy ant abundance appears to be
important in determining their role as opportunists or extirpators. Our findings are
similar to that of Walters and Mackay (2005), who showed that Argentine ants were able
to overcome the native ant Iridomyrmex ‘rufoniger ’ in laboratory trials only when
Argentine ant colonies were 5 to 10 times larger than Iridomyrmex colonies. Holway and
Case (2001) also showed the importance of colony size on exploitative and interference
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