Diversity and population dynamics of predatory fauna in the brinjal ecosystem under IPM and non-IPM situations

Abstract

The study was conducted to assess and document the diversity, abundance of insect predators and its relationship with weather parameters in brinjal ecosystem at Horticultural farm, Horticultural College and Research Institute, Thiruchirapalli. The study has shown that the Lynx spider, Peucetia viridana was the dominant species with relative abundance of 19.04% and 20.39%, respectively in IPM and non-IPM plots. Among the coccinellid predators, Brumoides sutularis was recorded as the predominant species with relative abundance of 13.82% and 20.42% in respective IPM and non - IPM plots. Simpson and Shannon Weiner index of the present study showed that the natural enemies’ population was abundant in intercropped (IPM) plot than in the non - IPM plot. Spider population fluctuated throughout the cropping period and exhibited positive correlation with maximum temperature (r = 0.097 to 0.465), morning relative humidity and negative correlation with rainfall (r = - 0.078 to - 0.395) exhibiting that the population buildup was good at high temperature. Similarly, correlation coefficient obtained for coccinellids also exhibited that the maximum temperature (r = 0.057 to 0.443), minimum temperature and morning relative humidity had positive effect on the population. Whilst, wind velocity and rainfall (r = - 0.020 to - 0.990) implicated negative effect on the population of coccinellid predators. The neuropteran and heteropteran predators showed negative correlation with maximum temperature, evening relative humidity and positive correlation with minimum temperature, morning relative humidity and rainfall.