The availability of a large morphometric data set from over 2,000 specimens of Virginia presented the opportunity to examine gape dimorphism within V. striatula and its potential adaptive significance in greater detail within this specialist species.

In V. striatula, females attain a larger SVL. Gape was strongly associated with increasing SVL in both males and females. Males have significantly larger gapes at all but the shortest SVLs and the dimorphism becomes significant ca 145mm SVL which correlates with sexual maturity.

The observed dimorphism is hypothesized to allow males to utilize a wider range of prey (earthworm) sizes at any SVL in order to successfully compete with females for the resource. This would be of particular importance to male fitness during years in which significant drought limits availability of prey.