The Effect of Crowding on the Reproduction of the House-Mouse (Mus musculus L.) Living in Corn-Ricks

Abstract

Post-mortem examination of four dense corn-ricks populations of wild house-mice (Mus musculus) showed that the populations were still increasing but that physiological and behavioral factors were tending to regulate density. These factors included lowered fecundity, reduced litter size, embryonic resorption, and increasing movement away from the ricks. Non-fecundity in both males and females was associated with excessive fat deposits. The main regulating factors operating in the oat and wheat ricks studied were similar to those reported as regulating density in confined experimental colonies of mice.