Human disturbance spurring the development of invasive characteristics in species

Odorous House Ant (Tapinoma sessile). Image credit, Noodle Snacks.A new study in the journal Biological Invasions finds evidence that human disturbance can spur the development of invasive characteristics in certain species.

Entomologist Grzegorz Buczkowski from Purdue University looked at the social characteristics of the odorous house ant Tapinoma sessile  in both urban and natural environments.

In natural settings of North America, this native ant lives in small colonies with a single queen (monogyny) and a single nest (monodomy). In urban settings the ants form supercolonies with multiple queens (polygyny) and numerous nests (polydomy).

Buczkowski  hypothesizes that this "remarkable transition in colony social and spatial structure and life history traits" may enable the ant "to prosper in human-modified environments and contribute to its ecological dominance and pest status."

However, the question arises of what is actually driving this dramatic change. For example, does this ant species possesses an inherent plasticity that enables it to modify its own social and life history characteristics to adapt to an urbanized setting? Or has human disturbance driven evolutionary changes in the ant leading to new characteristics in urban areas.

In the study title, Buczkowski refers to the "Evolution of invasive characteristics," however in an email exchange with me about this lingering question, he wrote,

"I use the term “evolution” in a lax sense, to indicate that T. sessile in urban environments are showing behaviors and colony features not observed in natural populations…This may not have genetic basis, but may simply be due to behavioral plasticity in the different environments.  Our future work will address genetics in T. sessile."

The results from this future research may help us better understand why certain species develop invasive characteristics in response to human disturbance while others do not.

--Reviewed by Rob Goldstein

Buczkowski, G. (2010). Extreme life history plasticity and the evolution of invasive characteristics in a native ant Biological Invasions DOI: 10.1007/s10530-010-9727-6