ON A CASE OF FACULTATIVE PARTHENOGENESIS IN 

 THE GYPSY-MOTH LYMANTRIA DISPAR L. WITH 

 A DISCUSSION OF THE RELATION OF PARTHENO- 

 GENESIS TO SEX 



RICHARD GOLDSCHMIDT, 

 KAISER-WILHELM INSTITUT FUR BIOLOGIE, BERLIN. 



In the discussion about the relation of parthenogenesis and 

 sex, revived after the discovery of the sex-chromosomes, cases of 

 facultative parthenogenesis in normally bisexual animals play a 

 rather doubtful part. As the great majority of such reports 

 belongs to the older and oldest literature, modern writers appear 

 sceptical in regard to their reliability. Therefore any new case 

 recorded under reliable conditions must command the attention 

 of biologists. 



The majority of the reports about facultative parthenogenesis 

 relate to the order Lepidoptera. In most cases only the hatching 

 of caterpillars from unfertilized eggs has been observed, which 

 is of no interest for us here. There are comparatively few cases 

 where adults have been raised and their sex stated. One set of 

 observations relates to the silk-moth. This case can be regarded 

 as settled. There can be no doubt to-day that there are races 

 of the silk-moth which exhibit regularly the phenomenon of 

 facultative parthenogenesis and that the normal number of both 

 sexes is produced from parthenogenetic eggs (for example, see 

 Hartmann, '12). Another set of facts relates to the Psychidse, 

 where parthenogenesis is a normal phenomenon, resulting in 

 female offspring. A third series of reports deals with occasional 

 cases of parthenogenesis in the gypsy-moth, Lymantria disbar L. 

 In 1870, H. Weijhenberg, Jr., reported that he had succeeded 

 in breeding 27 adults, 14 9 and 13 cf, from 60 virgin females 

 of this moth. He also obtained a second parthenogenetic brood, 

 but he does not give details (see Dohrn, '71). A second report 

 comes from G. Platner ('88). He claims to have obtained par- 

 thenogenetic eggs regularly by keeping the females isolated for a 



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