The aim of this work was at calculating allele frequency color polymorphism in a population of sunflower caterpillar, Chlosyne lacinia saundersi (Doubleday) from Londrina, Paraná State, Brazil. Allele frequency in insect populations can be used as genetic marker to compare populations from different geographical and host origins. There are three phenotypes conditioned by two loci interacting epistatically. The phenotypes are: rufa (oranged colored larvae), bicolor (black larvae with dorsal orange stripes) and nigra, larvae with the body entirely black, sometimes with dorsal yellow dots, best seen in the fourth and fifth instars. Samples were taken independently in an attempt to obtain all combinations of crossing among genotypes. The genetic mechanism of this polymorphism is well known. A Chi-Square test (chi2) was used to estimate the ideal sample size. The frequencies stabilized, with over 800 fourth and fifth instars larvae even with increased sample size. The allele frequencies were calculated based on the frequency of each phenotype. The allele R of rufa locus had a frequency near 7.0% and the allele r near 93.0%, the allele B (bicolor) had a frequency around 31.8% and allele b frequency near 68.2%.
Epistasis; population genetics; ecological genetics; phenotype
