Samenvatting
Organic farming -- characterised by the prohibition of synthetic pesticides and mineral fertilisers and emphasis on
ecological management -- is widely promoted as a strategy for farmland biodiversity conservation, yet the magnitude and
consistency of its benefits for arthropod diversity relative to conventional farming remain debated, particularly in tropical
South Asian agricultural contexts where the evidence base is thin. This study presents a systematic comparison of
arthropod diversity between certified organic and conventional farms across three crop systems -- paddy rice,
vegetables, and mixed horticulture -- in Andhra Pradesh and Karnataka, India, using standardised pitfall trapping, sweep
netting, and yellow sticky trap protocols at 72 farm sites surveyed over two complete crop cycles (2020-2022). A total of
684 arthropod species from 14 orders and 96 families were documented. Organic farms supported significantly higher
total arthropod species richness (mean 84.4 species per farm) than conventional farms (mean 58.4 species; +44.5%
difference; p < 0.001). The benefit was most pronounced for natural enemies -- predatory Carabidae (+68.4%), parasitoid
Hymenoptera (+72.8%), and predatory Araneae (+54.2%) -- and least pronounced for herbivorous Hemiptera (+12.4%).
Organic farms also showed higher functional diversity and lower dominance of pest species. Pesticide-free field margins
adjacent to both farm types provide critical arthropod diversity refugia, with margin species richness 38.4% higher than
field interior richness across both management types. The results confirm the substantial benefits of organic
management for arthropod biodiversity in tropical Indian farming systems.