INTRASPECIFIC VARIATION IN BODY SIZE AND FECUNDITY IN INSECTS - A GENERAL RELATIONSHIP

The relationship between intra-specific variation in female body size and potential fecundity was investigated using the published literatur e on 57 oviparous species of Coleoptera, Diptera, Ephemeroptera, Heter optera, Homoptera, Hymenoptera, Lepidoptera, and Trichoptera, and 11 s pecies of larviparous Aphidina and Diptera. Female body sizes were con verted to dry body weight. Variation in body weight and fecundity was expressed as percentage deviation from the median values. The in-creas e in fecundity with body weight was similar in most taxa, with only a few important exceptions. The common regression for oviparous and larv iparous species predicts a 0.95% increase in median fecundity for each 1% increase in dry body weight. The number of ovarioles (in 10 specie s of Coleoptera, Diptera, Hymenoptera and Orthoptera) also increased w ith body weight. The general relationship predicted a 0.81% increase i n ovariole number for each 1% increase in dry body weight. The slope o f ovariole number versus weight relationship was greater in species wi th many ovarioles than in species with few. The common slope of the fe cundity/size relationship is close to 1 and this indicates that female size is a principal constraint on insect potential fecundity.