EFFECT OF GROUP, VARIATION AND HERITABILI TY OF THE COMPONENTS OF FITNESS IN EISENIA-FOETIDA (OLIGOCHAETA, LUMBRICIDAE)

The high degree of phenotypic variation in Eisenia foetida was reveale d under the study of such characters as the size of cocoons (mm), the number of cocoons laid throughout 30 days, the number of larvae per co coon, the rate of maturation (days) and the weight of worms at the age s of 30, 60 and 90 days. Among all the components, moderate negative c orrelation was revealed between the duration of the development and th e number of larvae per cocoon (r=-O.3) and between the rate of maturat ion and daily overweight (r=-0.46). Ah other growth components and rep roductive efforts were not significantly correlated. The well - expres sed <<effect of group>> was revealed. In pairs maintained under high d ensity, one of the larvae had the rate of the development approximatel y equal to that observed under singular maintenance, while the growth of other one was significantly delayed. Under very high density, most of the larvae failed the rate of growth and maturation up to their com plete arrest, but some individuals could grow and develop fast enough, which caused the formation df discrete groups with individuals twice as large as the rest. The heritability of main components of fitness w as estimated using the method of regression <<offspring - mean of pare nts>>, ANOVA analysis of interfamilial differences of full siblings, a nd repeated measurement in pairs of individuals. Two of the characters (the number of larvae per cocoon and the number of cocoons) are impor tant for the overall fertility, however, we did not find additive gene tic variation of these characters in a technical culture of E. foetida , while the size of cocoons and the duration of embryonal development, which are less important for the fitness, had high heritability. The heritability of growth rate was substantially affected by the conditio ns of maintenance of the larvae. The genetic variation of the rate of maturation was not found, which can be explained by difficulties in th e precise measurement of this character. Under high density, the selec tion for growth rate was effective only when the parents were evaluate d at later stages of ontogenesis.