Relationship Between Eye Lens Weight and Age in the Wild House Mouse (Mus musculus)

Abstract

(1) Eye lens growth curves were obtained from 200 male and 208 female laboratory-reared wild house mice (Mus musculus L.) between 3 and 72 weeks of age. (2) The relationship between age and dried lens weight was derived by regression analysis. The equations fitted to data for males and females respectively were log10 (age + 20 days) = 1.019 + 0.175 (paired lens weight) and log10 (age + 20 days) = 1.004 + 0 182 (paired lens weight); the correlation coefficients of the relationships were 0.97 and 0-96 respectively. (3) Lens weights 'were also measured in 170 male and 194 female farm-living mice whose ages were accurately known. Lens weight-age relationships were comparable in captive and wild-caught animals. (4) The accuracy of the lens method in determining age was examined by comparison of known and predicted ages. Infant, juvenile and three age-classes of adult animals were reliably separated by lens weight. The technique thus appears to be useful in the analysis of population structure in wild house mice.