Nylanderia fulva, the tawny crazy ant (TCA), is an invasive species that is native to South America. TCA was first reported in Pasadena Texas in 2002. Little is known about TCA tunneling behavior in its native or invaded range. There are currently no reports of TCA building mounds or digging vertically into the substrate. How then might TCA colonize different areas and, how do they protect themselves from harsh environmental conditions? Recently it has been observed that TCA conduct horizontal subterranean tunneling (Bentley, Michael T., et al 2015.). Building upon this information, this experiment aimed to determine whether TCA vertically tunnels under different soil compositions.
The experiment placed two hundred TCA workers along with a queen into Plexiglass ant farms (dimensions 2.54 x 17.78 x 17.78 cm) containing one of three different soil compositions. TCA colonies were collected from three locations across Texas, and the experiment was replicated a total of four times. For each replicate, workers and queens were taken from the same colony and split three ways. Tunneling performance was measured over a two-week period. The three soil treatments consisted of sandy loam, predominately clay, or commercial potting soil. Sandy soils were representative of coastal soils; clay represented much of Eastern Texas, while potting soil represented urban environments.
Results/Conclusions
In a preliminary trial, TCA vertically tunneled on sandy soil to a maximum depth of 9 cm. This vertical tunneling was accompanied by approximately 17 cm of horizontal tunneling over a 2 month period. As time progressed the TCA developed an intricate set of connecting tunnels, and also the production of brood was observed. Data are currently being obtained for TCA in three soil treatments. Tunneling may be used by TCA as a strategy to survive in the dryer conditions present in their invaded area as compared to their native habitats. By observing TCA’s ability to tunnel under different soil compositions we can better understand their survival as an invasive species and their ability to colonize both natural and urban habitats.