An Analysis of Spot Placing in the Meadow Brown Butterfly Maniola jurtina

Abstract

The first study of the variation of spot-number in the Meadow Brown Butterfly, Maniola jurtina, was reported from the uninhabited island of Tean, Isles of Stilly, in 1946 (Dowdeswell, Fisher & Ford 1949). The work was extended to other islands of the Stilly archipelago and to sites in mainland Britain from 1950 onwards (Dowdeswell & Ford 1953). From that year the area of interest in Britain has steadily widened; in addition collections of imagines from virtually the whole geographic range and dating from between 1890 and 1935 have been analysed for spot-number distribution by Dowdeswell & McWhirter (1967). A review of our present knowledge in respect of the distribution of spotnumbers may be found in Ford (1971). Heritability of spot-number at 15°C has been estimated for females by two different methods at 63 and 83 per cent; corresponding male progeny did not show significant heritability (McWhirter 1969). At 22°C females show approximately 78 per cent heritability and males about 48 per cent (McWhirter, in preparation).