Esterase polymorphism in natural populations of a sulfur butterfly, Colias eurytheme.

Starch-gel electrophoresis of esterases of wild and laboratoryreared individuals of Colias eurytheme indicates that populations in central Texas are exceedingly variable, consisting almost entirely of heterozygotes formed from a large number of alleles at an autosomal locus controlling the production of an esterase designated EST E. Few wild individuals are genetically identical at this locus. The commonest member of the allelic series is an apparent null allele that results in no EST E activity.