Chemical quality impacts of tropical forest tree leaf litters on the growth and fecundity of soil Collembola

The growth performances of a soil microarthropod, Cyphoderus javanus Börner (Collembola: Hexapoda), were tested in microcosms on leaf litter of different tropical forest trees to compare their nutritional quality to detritivores. The macronutrient profile was more or less similar between the litter types, but the quantities of non-nutrients like polyphenols, tannins and lignins were notably higher in the litter of Acacia auriculiformis and Shorea robusta trees than in the litter of Cassia siamea and Dalbergia sissoo trees. A choice experiment showed persistently higher colonisation of Collembola on litter of Cassia and Dalbergia, which differed significantly from a trend of lower occurrence in Acacia and Shorea. The nutritional benefit of the litter types was compared by measuring levels of tissue carbohydrates, proteins and lipids in C. javanus. Analysis of data by t test showed that animals reared on Cassia and Dalbergia litters contained statistically significant higher concentrations of tissue carbohydrates and proteins than those fed on Acacia. But the differences with the animals fed on Shorea were not significant. In contrast, C. javanus registered significantly low levels of tissue lipids in Cassia and Dalbergia litters when compared to animals reared on Acacia and Shorea litters. The 2-way RM-ANOVA test revealed highly significant main effect of time intervals for tissue carbohydrates and proteins and highly significant main effect of litter types for tissue lipids. Benefits derived from litter quality on growth were seen from enhanced fecundity and higher rate of moulting of C. javanus reared on Dalbergia followed by Cassia, Acacia and Shorea in descending order. The higher reproductive rate on Dalbergia and Cassia probably resulted in decreased level of tissue lipids in animals. Growth parameters, namely tissue nutrients, fecundity and moulting were influenced by the chemical constituents of different litter types, and these qualities are potential indicators of the nutritional quality of litter to detritivores, and the ecological suitability of tree species for enhancing the biological activity in soil system.