Life Sciences Commons^™

The Reproductive Cycle Of Microtus Ochrogaster In Eastern Kansas, Robert K. Rose, Michael S. Gaines

Biological Sciences Faculty Publications

About 800 Microtus ochrogaster were live—trapped at biweekly intervals from May 1971 through March 1973 in 3 grassland study areas in eastern Kansas, USA. Details of reproduction were determined by autopsy. Population density increased through the first winter, reached a peak in April 1972, then declined sharply during that summer and beyond. Body length, but not body mass, tended to be positively related to density. Both sexes matured at about the same weight; development was somewhat prolonged during the winter months, especially in the winter preceding the population peak. Pregnancy rates were high, approaching maximal iteroparity, throughout the study, with …