Facultative Parthenogenesis in Collembola (Insecta)

Abstract

PARTHENOGENESIS in insects is well known, and its occurrence in the class is fairly widespread. In the order Collembola (the springtails) its presence has been suggested on rather disputable grounds and then afterwards denied on more than one occasion¹. Choudhuri gave the first real proof of the phenomenon within the order when he described² a new species of Collembola (Onychiurus parthenogeneticus). He was able to study this species not only by examination of museum material from Europe and Africa but also by observations on specimens maintained in culture for more than two years. No males of this species were ever seen by him. In all, some forty species of the genus were examined by Choudhuri, and this was the only species in which no males were found. This led to the assumption that the phenomenon may be rather rare in Collembola. Gisin³ placed O. parthenogeneticus as a junior synonym of O. hortensis Gisin, 1949, and stated that “die Kolonien offenbar meist aus lauter Weibschen bestehen”. This synonymy is not upheld by Choudhuri and Goto (in the press), but the two species are obviously very close. The suggestion that at least some males are present in Gisin's species indicates that facultative parthenogenesis might possibly occur in certain circumstances in Collembola.