202
B. L. ASTAUROV
alterations taking place during a very short period of development in a
single insect species are chosen as the subject of a special review.
B. Short Historical Survey
The first recorded instances of an exceptional mode of reproduction
in Bombyx mon L. were rare cases of larvae hatching from eggs laid by
virgin females. These astonishing cases of propagation "without the
concurrence of the male" naturally attracted great attention and curiosity. In all probability they should be retrospectively classified as cases of
spontaneous natural parthenogenesis. This spontaneous development in
the form of rudimentary parthenogenesis may be observed in a proportion of eggs in almost every batch laid by a virgin female. Occasionally
and extremely rarely individual eggs give rise to hatching larvae and
still more rarely these larvae appear to be capable of undergoing both
a successful and a complete development. The cytogenetic mechanism of
spontaneous parthenogenesis was revealed much later by Sato (1931),
Bataillon and Tchou-Su (1933), Frolova (1935), Kawaguchi (1934a),
and Astaurov (1940).
It was precisely in the silkworm that the phenomenon of artificial
parthenogenesis was demonstrated for the first time (Tichomiroff,
1886a,b). Little attention was paid to TichomirofFs discovery at first
(Verson, 1872, 1890; Nussbaum, 1899), possibly because Tichomiroff,
as well as his early followers, succeeded in producing only the initial
stages of development and only extremely rarely single hatched larvae.
Up to the early thirties there was no noticeable progress in the elaboration of a reliable method of artificial parthenogenesis in silkworms. In
1931, Sato reported the successful raising of several scores of adult
individuals from unfertilized ova by means of HC1 treatment, the details
of which remained unpublished. Sato's success revived keen interest in
this rather obsolete problem. Yet despite Sato's claim to have induced
artificial parthenogenesis, it soon became clear that he actually dealt
with spontaneous parthenogenetic development facilitated by HC1 treatment which eliminated the diapause in potentially hibernating eggs (the
so-called "artificial hatching" of sericulturists) (Astaurov, 1940). Almost
at the same time Koltzoff (1932a,b) and Vermel (1932, 1934) described
a number of promising procedures for the chemical induction of artificial
parthenogenesis. Frolova (1935) carefully examined Koltzoff's experimental material cytologically and described maturation and cleavage
processes in unfertilized activated eggs. Finally, definite progress was
achieved in the elaboration of an effective thermal method of complete
thelytokous parthenogenesis (Astaurov, 1940). The extensive literature,
until 1939, on parthenogenesis in the silkworm, both artificial and
spontaneous, is quoted in Astaurov's monograph (1940).
B. L. ASTAUROV
alterations taking place during a very short period of development in a
single insect species are chosen as the subject of a special review.
B. Short Historical Survey
The first recorded instances of an exceptional mode of reproduction
in Bombyx mon L. were rare cases of larvae hatching from eggs laid by
virgin females. These astonishing cases of propagation "without the
concurrence of the male" naturally attracted great attention and curiosity. In all probability they should be retrospectively classified as cases of
spontaneous natural parthenogenesis. This spontaneous development in
the form of rudimentary parthenogenesis may be observed in a proportion of eggs in almost every batch laid by a virgin female. Occasionally
and extremely rarely individual eggs give rise to hatching larvae and
still more rarely these larvae appear to be capable of undergoing both
a successful and a complete development. The cytogenetic mechanism of
spontaneous parthenogenesis was revealed much later by Sato (1931),
Bataillon and Tchou-Su (1933), Frolova (1935), Kawaguchi (1934a),
and Astaurov (1940).
It was precisely in the silkworm that the phenomenon of artificial
parthenogenesis was demonstrated for the first time (Tichomiroff,
1886a,b). Little attention was paid to TichomirofFs discovery at first
(Verson, 1872, 1890; Nussbaum, 1899), possibly because Tichomiroff,
as well as his early followers, succeeded in producing only the initial
stages of development and only extremely rarely single hatched larvae.
Up to the early thirties there was no noticeable progress in the elaboration of a reliable method of artificial parthenogenesis in silkworms. In
1931, Sato reported the successful raising of several scores of adult
individuals from unfertilized ova by means of HC1 treatment, the details
of which remained unpublished. Sato's success revived keen interest in
this rather obsolete problem. Yet despite Sato's claim to have induced
artificial parthenogenesis, it soon became clear that he actually dealt
with spontaneous parthenogenetic development facilitated by HC1 treatment which eliminated the diapause in potentially hibernating eggs (the
so-called "artificial hatching" of sericulturists) (Astaurov, 1940). Almost
at the same time Koltzoff (1932a,b) and Vermel (1932, 1934) described
a number of promising procedures for the chemical induction of artificial
parthenogenesis. Frolova (1935) carefully examined Koltzoff's experimental material cytologically and described maturation and cleavage
processes in unfertilized activated eggs. Finally, definite progress was
achieved in the elaboration of an effective thermal method of complete
thelytokous parthenogenesis (Astaurov, 1940). The extensive literature,
until 1939, on parthenogenesis in the silkworm, both artificial and
spontaneous, is quoted in Astaurov's monograph (1940).