Comparison of two independent scoring techniques for spot variation in Maniola jurtina (L.) and the consequences of some differences

Eight samples (total N = 298) of female meadow brown butterflies Maniola jurtina were scored independently by P. M. Brakefield and W. H. Dowdeswell for hindwing spot-number and spot-combination. Spot-size was measured by P.M.B. W.H.D scored 37% few spots overall than P.M.B. ( N = 554). This resulted in some marked differences in spot-frequency distributions. There was a rather narrow threshold of spot-size above which nearly all spots were scored by both of us and below which most spots were only scored by P.M.B. When the data of P.M.B. are transformed by excluding all spots below a threshold a close correspondence of spot-frequencies is found. Relative differences between samples tend to be maintained in the untransformed data. The consequences of the differences in scoring techniques are discussed.