The dry body weight of adult male Lepidoptera was estimated from thirteen linear measurements of the wings and body using multivariate regression techniques. A dataset comprising information from 2,645 species was used, significantly increasing sample size with respect to a similar former approach. Based on the logarithmically transformed values of dry body weight and several linear measurements the best single predictors for body weight are body length, thorax length and head width, none of which is among the most popular descriptors of size in this insect order (namely, forewing length and wingspan). The results show that combinations of several linear measurements lead to the most precise estimates of dry body weight. More simple models, e.g. based on wing length or wingspan and body length, may provide reasonable but suboptimal approaches. Variance partitioning of the regression residuals indicated that most of the non-explained variance is attributable to morphology rather than to phylogeny, so overall the results suggest that the best models may be stable and liable for prediction except for unusual morphologies. Alternative approaches such as a taxon-by-taxon approach or ANCOVA-based methods were tested, and the results -and problems involved- are discussed. The potential relevance of co-linearity is addressed to. Based on a limited number of species, the author attempted to estimate the female to male weight relation (which happened to be nearly isometric), as well as the percent water content (38% overall).<br> The dataset is made available so it can be accessed for any related research on this or related subjects.
