Population dynamics of rodents during bamboo flowering event in North East India

The ecological aspects of rodents during bamboo flowering (BF) phase (Mautam) were studied in Meghalaya and Mizoram states of India during 2005-2008. Rodent population was almost stable during BF in Meghalaya. Likewise, it was also normal in Mizoram during 2005 to 2007. However, rodent outbreak was observed after gregarious flowering (GF) of M. baccifera during 2007-08 in Mizoram and it was more severe after complete fruit shedding. Rodent activities were found to be highest during July to October and their population was significantly higher in upland cultivated areas especially near animal farm-houses. Out of 12 species recorded, merely six species of rodents were observed in BF areas of Mizoram. Surprisingly, Bandicota bengalensis was recorded to be a pre-dominant species, though not observed in bamboo forests. Species wise, sex ratio of rodents varied from 1:0.81 to 1:1.12 in Mizoram. Furthermore, rodent population was recorded to be higher in GF areas and location wise it was more in Kolasib district of Mizoram. In general, sex ratio of rodents was quite equal in all districts of Mizoram; however it was basically female biased in sporadic flowering (SF) areas. Maturity status of rodents in Mizoram indicated their complete adulthood during flowering time; where testes and vaginas were largely scrotal and perforated type, respectively. Overall study concludes that, bamboo flowering alone didn’t increase rodent population significantly; but other factors mainly weather and starting time of flowering could also be involved in this complex process.