The Journal of Heredity 



»CL. 



iMJG 



iMdcr 



ANTERIOR VIEW OF HEADS OF WORK- 

 ER (A), QUEEN (B) AND DRONE (C) 

 The front chitin has been removed to show 

 the internal glands, which vary in the three 

 forms. There is marked variation in the size 

 of the compound eyes at the sides of the head. 

 After Snodgrass Bull. Bureau Ent. 28. (Fig. 1.) 



Let us attempt from three different 

 points of view to attack these problems 

 that seem so perplexing. 



THE geneticist's METHOD OF ATTACK 



In the first place we may consider the 

 matter as viewed by the geneticist. 

 There are numerous instances of trans- 

 mission of qualities that appear only 

 under the influence of particular en- 

 vironmental conditions. The germ 



plasm of any species doubtless has 

 potentialities that are realized only 

 under exceptional circumstances or 

 not at all. Thus the factor for extra 

 legs in Drosophila is inherited as a sex- 

 linked gene, but the character appears 

 only if development takes place at a 

 cold temperature. A study of genetic 

 literature reveals many other examples 

 of masking of Mendelian differences 

 by environment. In stock of uniform 

 genetic character there may be con- 

 siderable variation as a result of change 

 of food, temperature, humidity, etc. 



It may then be answered that work- 

 ers are of the same genetic constitution 

 as the queen, but a difference of food 

 has dwarfed the ovaries and caused a 

 greater development of brain and in- 

 stincts. The fact that superior instincts 

 have not occurred in any of the worker 

 bee's direct ancestors is quite in line 

 with the problem of heredity as viewed 

 from the aspect of cell lineage. We 

 receive our hereditary characters not 

 from the body cells of our parents, but 

 from the germ tract extending back 

 indefinitely. The somatic cells of our 

 ancestors are "sisters" to their germ 

 cells, and "aunts" and "great aunts" 

 to our own, just as worker bees are 

 sisters to queens and drones and aunts 

 and great aunts to later generations of 

 workers. 



The germ plasm of the honey bee has 

 the capacity to develop worker as well 

 as queen qualities, and the difference 

 between worker and queen is deter- 

 mined by the food of the larva. 



The difficulty which appears in the 

 derivation of drones from virgin queens, 

 is again due to the idea that characters 

 are inherited as such from the parent. 

 The drone does not derive its charac- 

 ters from egg-laying workers or un- 

 mated queens. On the contrary it 

 derives a simplex assortment of genetic 

 factors or of chromosomes in the unfer- 

 tilized egg. This simplex condition 

 determines the male, just as the duplex 

 determines the female. If honey-bees 

 were able to lay unreduced eggs, as are 

 various species of parasitic wasps and 

 aphids, then females would be produced 

 parthenogenetically. Or if two sperm 



