ABSTRACT
Examining Competitive Interactions Between Rasberry Crazy Ants
(Paratrechina sp. ra.pubens} and Red Imported Fire Ants (Solenopsis
invicta) Using Laboratory and Field Studies
by
Katherine Hom
Studying nonnative species soon after their introduction is critical to
understanding their risk of becoming widely invasive and determining effective methods
of control. I conducted laboratory and field experiments on the Rasberry crazy ant
(Paratrechina sp. nr. pubens), which was introduced to Pasadena, TX in 2002 and has
since been spreading rapidly. These experiments focused on intraspecific aggression, as
well as individual and colony-level interactions between crazy ants and red imported fire
ants (Solenopsis invicta), which are dominant in the crazy ant’s introduced range. Crazy
ants displayed no intraspecific aggression. In individual aggressive encounters with fire
ants, crazy ants had higher mortality than fire ants, but in colony-level clashes, crazy ants
had less mortality and better control of food resources. These findings suggest that crazy
ant abundance is key to their competitive success, and fire ants may provide biotic
resistance to crazy ants in some areas.
ii