Soil macroinvertebrates are highly diverse and their major ecological service include breakdown of organic matter and in turn improve soil fertility and pill-millipedes are well-known for their signi?cant role in ingestion,disintegration and decomposition of organic matter in soil.This study characterized the feed,the decomposing leaf litter of coconut(Cocos nucifera),and faeces of two endemic giant pill-millipedes Arthrosphaera disticta and A.fumosa collected from forests of the Western Ghats of India based on chemical features and microbial pro?le.In both millipedes,electric conductivity and total phosphorus were signi?cantly increased in faeces,while the crude protein,organic carbon,total nitrogen and total phenolics were signi?cantly decreased,as compared to those in feed.Heterotrophic bacteria,actinomycetes,rhizobia and phosphate-solubilizing bacteria were signi?cantly higher in faeces than in feed,while ?lamentous fungi and yeast substantially decreased in faces compared to feed in both the millipedes.Spectrum of fatty acid methyl esters was considerably different between feed and faeces of both the millipedes.The total saturated fatty acids were higher than the total unsaturated fatty acids in feed as well as faeces,while the ratio of unsaturated/saturated fatty acids decreased from feed to faeces.Dodecanoic and tetradecanoic acids in A.disticta and octadecanoic acid in A.fumosa signi?cantly increased,while(9Z)-octadec-9-enoic and(9E,12E)-octadeca-9,12-dienoic acids in A.disticta and hexadecanoic,tetracosanoic and(9E,12E)-octadeca-9,12-dienoic acids in A.fumosa signi?cantly decreased in faeces compared to feed,indicating millipede-dependent changes in fatty acids.Icosanoic acid was present in faeces of both the millipedes,and hexadec-9-enoic acid was con?ned to faeces of A.disticta,while pentadecanoic,heneicosanoic,(9Z,12 Z,15Z)-9,12,15-octadecatrienoic and eicosenoic acids were con?ned to faeces of A.fumosa.Pill-millipedes enrich the soil quality by leaf litter conditioning in their gut through speci?c microbial communities.Fingerprinting of fatty acid methyl esters in faeces of these millipedes re?ected the activity of speci?c microbial population in their guts. Soil macroinvertebrates are highly diverse and their major ecological service include breakdown of organic matter and in turn improve soil fertility and pill-millipedes are well-known for their signi? Cant role in ingestion, disintegration and decomposition of organic matter in soil. This is a. the feed, the decomposing leaf litter of coconut (Cocos nucifera), and faeces of two endemic giant pill-millipedes Arthrosphaera disticta and A. fumosa collected from forests of the Western Ghats of India based on chemical features and microbial pro? le. both. millipedes, electric conductivity and total phosphorus were signi? cantly increased in faeces, while the crude protein, organic carbon, total nitrogen and total phenolics were signi? cantly decreased, as compared to those in feed. Heterotrophic bacteria, actinomycetes, rhizobia and phosphate- solubilizing bacteria were signi? cantly higher in faeces than in feed, while? lamentous fungi and yeast substantially less in faces compared to feed in both the millipedes.Spectrum of fatty acid methyl esters was quite different between feed and faeces of both the millipedes. The total saturated fatty acids were higher than the total unsaturated fatty acids in feed as well as faeces, while the ratio of unsaturated / saturated fatty acids decreased from feed to faeces. Dodecanoic and tetradecanoic acids in A. disticta and octadecanoic acid in A. fumosa signi? cantly increased, while (9Z) -octadec-9-enoic and (9E, 12E) -octadeca-9,12 -dienoic acids in A. disticta and hexadecanoic, tetracosanoic and (9E, 12E) -octadeca-9,12-dienoic acids in A. fumosa signi? cantly decreased in faeces compared to feed, indicating millipede-dependent changes in fatty acids. Icosanoic acid was present in faeces of both the millipedes, and hexadec-9-enoic acid was con? ned to faeces of A. disticta, while pentadecanoic, heneicosanoic, (9Z, 12Z, 15Z) -9,12,15-octadecatrienoic and eicosenoic acids were con? ned to faeces of A.fumosa.Pill-millipedes enrich the soil quality by leaf litter conditioning in their gut through speci? c microbial communities. Fingerprinting of fatty acid methyl esters in faeces of these millipedes re? ected the activity of speci? c microbial population in their guts.