GROWTH AND REPRODUCTION OF PERIONYX EXCAVATUS (PERR.) (MEGASCOLECIDAE) AS FACTORS IN ORGANIC WASTE MANAGEMENT

The life cycle of Perionyx excavatus has been studied and the potentia l of this epigeic earthworm species for breaking down and processing o rganic wastes is well known. Understanding of its optimal environmenta l requirements is required in order to optimize and accelerate the ver micomposting process. The rates of growth and reproduction of P. excav atus, on a variety of organic wastes, were evaluated in these experime nts. The time of maturation and the rates of growth of this species, u nder various population density pressures and temperatures between 15 degrees C and 30 degrees C, were also assessed. increasing temperature s up to 30 degrees C accelerated the growth of earthworms and lessened the time to sexual maturity. However, the highest rates of reproducti on occurred at 25 degrees C both in cattle solids and sewage sludge. T he mean time to egg hatching decreased and the degree of hatching succ ess increased with increasing temperature. Earthworms grew at similar rates in cattle solids, pig solids and aerobically digested sewage slu dge, but the earthworms did not grow well in horse solids and grew onl y poorly in turkey wastes. The maximum individual growth rates as a fu nction of earthworm population and the maximum earthworm weights as a function of time with a constant food supply at four different tempera tures were assessed.