[Transmission analysis of the B chromosomes in Locusta migratoria migratorioides R. et F. (Orthoptera, Acrididae) (author's transl)].

In a African grasshopper population of Locusta migratoria migratorioides reared in the laboratory, B chromosome transmission is analysed in progeny of pairs taken at radom from the population. An accumulation mechanism of Bs exists in the females which presumably results from preferential egregation of the Bs in the female pronucleus. The analysis also shows B chromosome elimination during embryonic and larval development by means of mitotic non-kisjunction: these non-disjunctions induce interfollicular variations in the number of Bs but all the cells of a follicle have the same number of Bs. The frequency of animals with B chromosome rises from 34% to 75% as the diurnal temperature rises from 27 degrees C to 35 degrees C. Thus frequency is controlled by genetic and environmental factors.