The Reproductive Processes and Parthenogenesis 187 



In 1745, Bonnet described the parthenogenetic develop- 

 ment of plant lice and just one hundred years later Dzierzon 

 announced his theory that the drone is likewise a product 

 of an unfertilized egg. This later paper, published in the 

 Eichstadt Bienenzeitung, was the beginning of a long and 

 heated discussion in which the leading zoologists of the day 

 took part. Briefly his theory was as follows : (1) the queen 

 is able "at pleasure" to lay either worker or«drone eggs, the 

 drone eggs being deposited just as they leave the ovary ' ; 

 (2) all eggs in the ovary are eggs which would normally 

 develop into males and if fertilization occurs the sex is 

 changed to female. It is well to divide Dzierzon's theory 

 into these two parts for they are not equally capable of proof. 



The facts observed in the apiary on which this belief is 

 based are as follows : (1) If a queen is unable to fly out to 

 mate or is prevented from mating in some other way she 

 usually dies (p. 70) but if she does lay eggs, as she may, 

 after three or four weeks, the eggs which develop are all males ; 

 (2) if when a queen becomes old her supply of spermatozoa 

 is exhausted, her offspring are all males ; (3) if a colony be- 

 comes queenless and remains so for a time, some of the 

 workers may begin egg-laying and in this case too only 

 males develop. The author has found that many eggs laid 

 by drone-laying queens fail to hatch and, in fact, are often 

 removed in a short time by the workers. This makes it 

 impossible for us to accept Dzierzon's statement that all 

 eggs laid by such a queen become males and the statement 

 must be modified as follows : all of those eggs laid by a drone- 

 lajdng queen which develop become males. The poten- 

 tialities of the eggs which never hatch are not known. In 

 addition to the facts here stated, the theory of the partheno- 

 genetic development of the drone is supported by investiga- 

 tions of the phenomena of development in the egg. 



1 Onions (1912, South African fertile-worker bees. Agricultural Journal 

 of the Union of S. Af ., May) claims that in South African bees females are also 

 produced parthenogenetically. The claim is supported by considerable 

 evidence. See also Van Warmelo, D. S., ibid., 1913, who denies this state- 

 ment. 



