The genetics of colour-patterns in the grasshopper Chorthippus brunneus

Several alleles were found to determine the colour of the dorsal pronotum in Chorthippus brunneus; there was evidence for at least two loci ( C and V ). Brown ( C^B )was the universal recessive and green ( C^C ) was dominant to all other colours. The white allele ( C^W )was codominant with green( C^G )and purple ( C^P ). Wing-patterns were determined by a separate, probably linked locus ( W ). A dominant plain wing-pattern ( W^P ) was associated with colours other than brown. Striped( W^S )and mottled( W^mo ) were codominant and a plain recessive allele ( W^P ) was also found. All three alleles were associated with the brown phenotype. A purple-sided allele ( S^Pu ) was sometimes obmd with C^pu.. S ^Pu was dominant to brown sides ( S^B ), A series of markings on the dorsal and lateral pronotum ( linea intermedia, fascia postocularis, linea media, carina media and zona lateralis ) were investigated and found to be controlled at separate loci which may be linked to W . These characters were expressed by dominant alleles.
Epistatic effects by modifier loci were shown to have an important effect on the determination of wing phenotype. Allele Wo⁺ , for example, suppressed the stripe-wing pattern, linea media, carina media and zona lateralis .
It was concluded that colour patterns appear to be under genetic control and that dominant alleles were rare in the wild. Changes in shades of colours were shown to be age-dependent and minor.