Influence of different food sources on growth and reproduction performance of composting epigeics: Eudrilus eugeniae, Perionyx excavatus and Perionyx sansibaricus

Abstract

The impact of organic material quality on biomass production and reproduction potential of commercial composting earthworm species: Eudrilus eugeniae, Perionyx excavatus and Perionyx sansibaricus were studied, by using three different type of culture material namely Jbs: (Jowar straw (Sorghum vulgare) + bajra straw (Pennisetum typhoides) + sheep manure) (1:1:2), fym (farmyard manure), and Kw + Ll (Kitchen waste + leaf litter of Magifera indica) (1:1), under laboratory conditions for 150 days. The above substrate or culture materials have different palatability, particle size and physiochemical composition. Kitchen waste (C-to-N = 26.7) as well as farmyard manure (C-to-N = 27.4) is a high quality material with fast decomposition rates, while crop residues are low quality materials with slow decomposition rates (C-to-N = 45.6). All the three studied earthworm species showed maximum biomass production rate in Kw + Ll culture (E. eugeniae = 9.80 ± 0.01 mg worm-1 day-1, P. excavatus = 3.75 ± 0.01 mg worm-1 day-1, and P. sansibaricus = 3.77 mg worm-1 day -1). Individual cocoon production rate varied drastically, and maximum value (worm-1 week-1) of it was observed in Kw + Ll for E. eugeniae (1.88 ± 0.15) and P. sansibaricus (1.77 ± 0.14), while P. excavatus showed maximum cocoon production rate in Fym (1.79 ± 0.17). The hatchling success of cocoons obtained from different beddings was also observed and cocoon obtained from Kw + Ll culture exhibited maximum hatchling success (%) in all the three species studied. The cocoons of both E. eugeniae and P. sansibaricus, obtained from Fym culture showed the highest number of hatchlings (cocoon-1) i.e. 1.59 ± 0.04 and 1.81 ± 0.10, respectively, whereas cocoons of P. excavatus showed the highest hatchling number (1.77 ± 0.06) in Kw + Ll. In this present study, there was a consistent trend of decreasing individual biomass as well as cocoon production rate, followed by their peak values with ageing of the culture materials. The relationship between different earthworm parameters and N-content or C-to-N of culture material was also evaluated. The biomass production rate and hatching success in all the three species studied showed direct correlation (p<0.05) with N-content of the culture material. However, beddings' N-content did not affect the individual cocoon production rate, except to P. sansibaricus (r = 0.987, P<0.001). The number of hatchlings per cocoon for P. sansibaricus, showed good correlation (r = 0.935 p<0.01) with N-content of organic material used for worm culture. Results clearly show a possible relation between hatchling success/number of hatchlings per cocoon, and chemistry of culture substrate. © 2007, Penkala Bt.