QUANTITATIVE GENETICS OF THE TRADE-OFF BETWEEN FECUNDITY AND WING DIMORPHISM IN THE CRICKET ALLONEMOBIUS-SOCIUS

Considerable evidence indicates that in general there is a phenotypic trade-off between wing dimorphism (a threshold trait) and fecundity in insects. However, the demonstration of a genetic basis to this trade- off has been shown in only one species, Gryllus firmus. In this paper we present evidence for another species, the cricket Allonemobius soci us. There were significant negative phenotypic correlations between wi ng morph and fecundity during the first two periods following eclosion (0-12 days and 13-16 days) and also cumulative fecundity (i.e. macrop terous females laid fewer eggs than micropterous females). Macropterou s and micropterous females did not differ in fecundity during the rema ining two periods (17-20 days and 21-24 days). Both wing morph and age -specific fecundities had significant heritabilities. There was a sign ificant negative genetic correlation between wing morph and fecundity during the first 12 days after eclosion. The standard errors of the es timates for the remaining periods were too large to permit a meaningfu l conclusion. Analysis of family mean data indicated that fecundity di d not vary in a dichotomous manner with wing morph but was best descri bed as a continuous function of the underlying continuously distribute d trait.