The dynamics of rats and mice populations inhabiting wheat-sugarcane based croplands in central Punjab (Pakistan)

The study was carried out on a 100-acre block of wheat-sugarcane based cropland of central punjab (pakistan). apart from wheat and sugarcane,crops of cotton,fodders and vegetables were also grown in the study block. all these five crops were snap-trapped for rats and mice each month from august (1993) to june (1994). from 6665 trap nights,689 animals belonging to the lesser bandicoot rat (bandicota bengalensis),house mouse (mus musculus),metad or soft-furred field rat,(millardia meltada) and indian gerbil (tatera indica) were caught; the overall trap success for the fields under sugarcane,fodders,cotton,wheat and vegetables were 16.2%,11.7%,8.9%,6.4% and 5.3%,respectively. the house mouse was numerically predominant in all the crops except for the sugarcane crop where the mouse,the bandicoot rat and metad had comparable trap successes. the murid populations of the cane,fodder,cotton and vegetable crops generally peaked in the fall and then declined rapidly but at varying rates. colonization of the wheat fields was initiated by the house mice in january. from february to may,the combined trap success of the four murid species in the wheat fields varied between 6.4-7.7%. the estimated annual rate of reproduction for the bandicoot rat population,with 0.472 prevalence of pregnancy (p),8.41 incidence of pregnancy (f),and with a litter size of 7.1,was 59.7 young/female/year. the annual rate of reproduction of the house mouse population was 66.6 (p=.507; f =9.0; litter size = 7.4),for the metad population it was 51.2 (p=.458; f= 8.7; litter size = 5.9) and for the gerbil population it was 26.1 (p=.222; f=4.0; litter size =6.2). copyright 2010 zoological society of pakistan.