size and habitat type may be key factors in the crazy ant invasion. Crazy ants can coexist
with fire ants in low abundances in open habitats (as shown with pre-crazy ant addition
field baiting results), yet observations have shown high abundances of crazy ants and an
absence of fire ants in invaded woody areas. Crazy ants are more successful in clashes
with fire ants on a colony- rather than an individual-level, yet relative abundance alone
cannot explain the invasion dynamics, as open areas adjacent to heavily invaded
woodlands are often nearly absent of crazy ants. Further studies examining invasion
front dynamics may be useful in testing this hypothesis, yet our findings are a key
preliminary step that suggests that crazy ant invasions may be restricted to wooded areas
and areas free of fire ants, as they are competitively excluded by fire ants in open areas.
Beyond the implications for Rasberry crazy ant management, this study has
important implications for the field of invasion biology. As the first study to
experimentally examine biotic resistance to a newly introduced species by an established
invasive species, these findings demonstrate the importance of competitive interactions
between invasive species in the introduced range, which have been largely ignored (but
see Belote and Weltzin 2006 and Griffen et al. 2008). The results of this study give
compelling reason for further study of antagonistic interaction between introduced
species, as research in this area may help not only with species-specific applied issues,
but also with our understanding of invasion biology as a whole.
Acknowledgements
I would like to thank Matt Barajas, Juli Carrillo, Marilu Corona, Christopher
Gabler, Johanna Hom, Summer Jones, Matt King, Maria Meza-Lopez, Max Quintanilla,
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