Some Observations on the Variability of Locusta migratoria, L., in Breeding Experiments

Abstract

My breeding experiments on Locusta migratoria, L., in 1913−14 enabled me to establish that the progeny of this species sometimes belongs to the form which was previously regarded as a distinct species, L. danica, L., and in the same way, the latter insect may give rise to progeny that is typical of L. migratoria. These results have been used by B. P. Uvarov in developing his theory that the periodicity of locusts is due to a kind of irregular alternation of two phases, swarming (ph. migratoria) and solitary (ph. danica), respectively. I shall not dwell here on that theory or on the differences between the two phases, referring those interested in the subject to Uvarov's paper, but will describe further breeding experiments conducted during the year 1923 with a view to obtaining an idea as to what may be the factors that cause the variation in the species.