Influence of seasonal environmental factors on growth and reproduction of the epigeic earthworm, Eisenia fetida (Savigny 1826).

Abstract

Eisenia fetida cultured in cattle manure in different seasons grew rapidly during initial weeks of development. Biomass in subsequent weeks increased gradually upto 16 weeks in summer and in winter but, in monsoon it declined from the 7th to the 16th weeks. However, the biomass of worms cultured in three seasons did not significantly differ. Growth rate of worms also increased steeply in all the seasons till the commencement of cocoon production. It was significantly (P < 0.05) lower in summer than in monsoon. Cumulative cocoon number per worm at the 16th week were 1.1, 12.2 and 13.9 during summer, monsoon and winter respectively. Cumulative cocoons and cocoon rate in winter and monsoon were almost similar and significantly (P < 0.01) higher than those of summer. More biomass and faster growth rate of worms during summer than in other seasons appeared to be because of less cocoons produced due to high and widely fluctuating room temperature (RT) and low and widely fluctuating relative humidity (RH). Higher biomass and growth rate concomitant with more cocoon production during winter than during monsoon may be attributed to the low range and mean RT and moderate RH. Growth and reproductrion during monsoon and winter though not varying significantly, were slightly less in the former than in the latter, which could be due to slightly enhanced RT despite its fluctuation being less and RH being high. From the above results, it could be concluded that the seasonal environmental factors prevailing during winter are most congenial, Followed by monsoon for culturing E. fetida.