ability in Argentine ants, as every measure of competitive performance increased with
worker number. As shown in Chapter 2, fire ants are more successful than crazy ants in
individual interactions, yet our findings in the laboratory experiment show that crazy ants
can be more successful at a colony level when colony units are closely matched by
biomass or worker number. Our field results reinforce the importance of relative crazy
ant abundance, as crazy ants recruited to resources in much lower numbers than fire ants
and behaved as opportunists, rather than controlling the baits which they discovered first.
In the field experiment, fire ant recruitment decreased in both control and crazy
ant addition locations (Figure 3.6). Though crazy ant recruitment increased through time
in the crazy ant addition treatment, our data suggest that the decrease in fire ant
recruitment is not due to the introduction of crazy ants. Simply, the addition of crazy ant
colonies did not cause an immediate and effective displacement of fire ants. Fire ant
decline may have been due to environmental factors such as the drought and extreme heat
in the weeks prior to and during the duration of the field experiment, when it rained only
once. In a laboratory and field experiments, fire ant foraging and bait retrieval has been
shown to decrease in increasing temperatures (Drees et al. 2007, Zheng et al. 2007).
Field temperatures often exceeded 35°C in June and July, which may have
contributed to the decrease in fire ant recruitment during the experiment. Additionally,
fire ants have been found to have higher sιmιmer mortality (personal communication, M.
Eubanks). Therefore, crazy ants, which have been reported to increase in abundance
during the summer months (personal observation, T. Rasberry), are likely responding to,
rather than driving, a decrease in fire ant recruitment. Reports in the popular press (such
as Blumenthal 2008) that crazy ants rapidly displace fire ants are likely not true. The
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