Colour Pattern Polymorphism in the Grasshopper Phaulacridium Vittatum. I. Geographic Variation in Victoria and Evidence of Habitat Association.

Abstract

The frequencies of the 3 colour pattern morphs (plain, striped and incomplete-striped) in samples of Phaulacridium vittatum (Sjost). from pasture sites in Victoria, Australia, did not conform to the pattern predicted by the latitudinal cline in morph frequencies previously described in south-eastern Australia. Data from 2 transects across pasture-forest boundaries revealed the existence of habitat associations, with forest habitats having a higher frequency of the plain morph. The proximity of some pasture populations to forests may explain some of the variation in morph frequencies observed among pasture sites. However, the frequency of the striped morph was relatively low in all the populations examined; this suggests that there are strong selective constraints on the frequency of striped individuals.