Al-FARABI KAZAKH NATIONAL UNIVERSITY Biology and Biotechnology Master students 1 st course : Mendygalyev Bekzhan INTRODUCTION he composting earthworm species Eisenia fetida is the most widely used commercial earthworm. This species seems to adapt to a wide range of environmental changes and feeds. The survival strategies of species are also well known from research done in laboratories. The fact that most of the research done in laboratories does not correspond with the performance of this species in commercial vermicomposting is the motivation for this research. Commercial vermicomposting companies and individual gardeners found that the margins for survival and performance differ from that published for the species. In this study the factors that may influence the reproduction and survival strategies of this species is investigated. The vermicomposting process in containers and beds systems depends heavily on the population structure of the earthworms. Mature unproductive earthworms produce a smaller volume of vermi-casts per day per earthworm than young growing and reproductive earthworms. The ideal population would be a active breeding population to give maximum vermicompost production. The ideal population would have more female functioning earthworms, hiperparious earthworms (Meyer & Bouwman, 1997) and a high number of juveniles – the most active feeders. The only way to ensure an ideal population is to encourage female functioning (Meyer & Loots, 1999). The influence of the following factors on the sexual status of the earthworms is investigated in a preliminary study. a) The influence of biomass on their sexuality b) The influence of population stress on sex c) The influence of age on sexuality. d) The irreversibility of sex e) Sexual change –compulsory / coincidental The influence of temperature on sex. The influence of food availability on sex Is there any chemo-communication to determine sex. Material & Methods All experiments were done with 40 pairs to ensure statistical reliability. All experimental earthworms were raised individually to ensure no chance of mating (virgin worms) before the start of the experiments. All worms were raised and kept at 25° C for the entire period of the experiment except where temperature was used as a variable. All worms were fed the same amount (5 gm) of cattle manure medium each week except where food availability (stress) was tested. All pairs for mating were determined with the aid of statistic tables. All earthworms were weighted at the start of the mating period, at the end of the mating period and weekly thereafter. All cocoons were collected weekly and recorded. Each pair and individual or group mated was kept record off. Anisoparious behavior was determined per pair or mating group, from the data collected, after the completion of each experiment. CONCLUSION The factors that may have an influence on the sex preference of Eisenia fetida earthworms is biomass, population density and age. Biomass is linked to food quantity, quality, and commercial vermicomposting should pay attention to the nutritional level of the worms. The population density must be controlled in commercial vermicomposting for optimum results. This two factors should be checked and regulated to give optimum age ratio in the population for best results. MECHANISM FOR POPULATION CONTROL IN THE COMPOSTING EARTHWORM SPECIES EISENIA FETIDA
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