摘要 : Studies were undertaken on diversity of predatory coccinellids in two agro-ecosystems comprising cereals, pulses and vegetables in Madurai District of Tamil Nadu. Field experiments were conducted in weeded and partially weeded irr... 展开 Studies were undertaken on diversity of predatory coccinellids in two agro-ecosystems comprising cereals, pulses and vegetables in Madurai District of Tamil Nadu. Field experiments were conducted in weeded and partially weeded irrigated (rice) and garden (cowpea) ecosystems at Agricultural College and Research Institute, Madurai. A total of nine species of predatory coccinellids were recorded. Three common species <i>viz.</i>, <i>Coccinella transversalis</i> Fabricius, <i>Menochilus sexmaculatus</i> Fabricius and <i>Brumoides suturalis</i> Mulsant were found in cereals, pulses and vegetable crops. Tomato and bhendi had rich abundance of coccinellids in Madurai, while chillies, cowpea, blackgram and bitter gourd in Alagarkovil. Diversity was high in crops like tomato, bhendi, chillies, blackgram and bittergourd in Madurai and in rice and cowpea in Alagarkovil. Rank abundance values revealed that <i>C. transversalis</i>, <i>Micraspis discolor</i> and <i>B. suturalis</i> were the dominant taxa in weeded and partially weeded rice ecosystem. <i>M. sexmaculatus</i>, <i>C. transversalis</i> and <i>B. suturalis</i> were the dominant taxa in weeded and partially weeded cowpea ecosystem. The diversity of coccinellids was greater in partially weeded plots than in weeded plots, particularly during the successional stage of crop growth and less during early vegetative stage and before harvesting. Rates of community turnover of coccinellids increased in both the weeded and partially weeded canopy with the crop age but at a faster rate in partially weeded canopy. This study suggests that partially weeded rice or cowpea ecosystem could be a better choice for conserving predatory coccinellid fauna instead of complete weeding, which would play a vital role in the natural suppression of insect pests. 收起