invasive species in their shared introduced range (but see Belote and Weltzin 2006 and
Griffen et al. 2008), and to my knowledge no studies have explicitly tested the negative
effects of long established species on new invaders. Therefore, I tested for biotic
resistance to a new introduction of a non-native species by an established invasive
species, using ants as a study system.
In 2002, the Rasberry crazy ant, Paratrechina sp. nr. pubens, was unintentionally
introduced to an industrial area along a ship channel in Pasadena, TX (Meyers 2008).
Since its introduction to Texas, populations OfRasberry crazy ants have spread by 20-
30m per month (Meyers 2008), and as of 2008 crazy ants had been reported in the
following Texas counties: Bexar, Brazoria, Fort Bend, Chambers, Galveston, Hardin,
Harris, Jefferson, Jim Hogg, Liberty, Montgomery, Orange, Walker and Wharton (Texas
A&M 2008). The high rate of range expansion, along with the presence of extremely
high densities of crazy ants in invaded areas, suggest that this exotic ant has the potential
to become widespread and invasive. Additionally, very few pest control products, none
of which are directly available to consumers, have been found to be effective in
controlling crazy ant invasions (Texas A&M 2008).
Little is known about this species, including its native range and precise
identification. Taxonomists have observed morphological and behavioral differences
between Texas populations of P. sp. ш. pubens and the previously described P. pubens,
yet the classification of P. sp. nr. pubens as P. pubens or an Xmdescribed species remains
inconclusive (Meyers 2008). The biology of the crazy ant is largely unknown, but the
species is known to be polygynous and to nest ephemerally. Though crazy ant colonies