Parallel polymorphism for supernumerary segments in Chorthippus parallelus (Zetterstedt)

Karyomorph comparisons within the Ashurst population during 1968 give evidence both of a temporal and a spatial distribution within the population. The former is seen with respect to the distribution of M₇ karyomorphs which show a Hardy-Weinberg pattern in the earliest collection but not at other times. The latter is revealed in the distinctive character of the B-site sample where the basic homozygous and the heterozygous S₈ karyomorphs approximate more closely in frequency than at any other site. Individuals polysomic for the M₄ chromosome have been recovered from the population over three successive years of sampling and confer a distinctive karyological structure on it.