interactions. What may seem surprising is that the data show that crazy ants receiving
fewer carbohydrates engage in more aggressive interactions with fire ants (Figures 2.3).
However, in a study examining the effect of diet on intraspecific interactions in Argentine
ants, Grover et al. (2007) found that aggression was decreased in the absence of sugar,
but there was no difference in aggression scores between low sugar and high sugar
treatments. Furthermore, per capita activity (based on the exploration of a structure not
containing food) was higher in the low sucrose treatment than in either the sucrose-free
treatment or the high sucrose treatment. In light of these findings, it is conceivable that
crazy ants that are sugar-limited may experience increased per capita activity and
therefore engage in more intense fights with another species, in this case fire ants. The
fact that there was no effect of sugar level on mortality suggests that fighting intensity is
not closely correlated with mortality for Rasberry crazy ants. Overall, the finding of
increased aggression score on a low sugar diet provides new insight in the behavior of
crazy ants, showing a similarity to the highly invasive Argentine ant (Grover et al. 2007).
The findings of this study give insights on the biotic factors affecting the spread
of the introduced Rasberry crazy ant populations. The most common ant in the
introduced range, the red imported fire ant, has less mortality when facing off in fights
with crazy ants. Additionally, small fire ants, which are most common, engage in fights
more often than larger fire ants. Together, these results suggest that fire ants may have a
competitive advantage over crazy ants and may be able to defend their territory from a
neighboring colony of crazy ants, though colony-level studies will put the individual-
level advantage in the context of relative abundance and worker activity. On the other
hand, when crazy ants consume a reduced sugar diet, they fight more intensely, without a
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