Pest Management Science 2013; 69:371-377
BACKGROUND: Multimammate mice are the most important vertebrate pests in Sub-Saharan Africa and are also reservoirs of
many zoonotic diseases, including sylvan plague. This study investigated the population dynamics and breeding patterns of
this mouse in irrigated rice cropping systems in eastern Tanzania.
RESULTS: The multimammate mouse, Mastomys natalensis, population varied with habitat and months. Fallow land had a more
abundant population than rice fields. The highest population peak was observed during the dry season from July to October.
Mastomys natalensis is sexually active throughout the year in the study area, although it reaches the highest level in June and
December when rice is at the maturity stage. This suggests that breeding is highly influenced by the presence of a rice crop in
both seasons. More juvenile individuals were recorded in August and September, indicating that they were produced in the
previous breeding months. The sex ratio of M. natalensis was not skewed to either males or females, indicating that it was at
parity.
CONCLUSION: Rodent population dynamics during the study periods in all habitats indicated that high birth rates accounted
for the rapid population growth and turnover. Regular control and sustainable operations are thus essential if rodent pest
populations are to be kept within tolerable limits.