254 THE STRUGGLE FOR THE LIFE OF OTHERS. 



mine sex by turning off or on the steam in a green- 

 house. With regard to bees tlie relation between 

 nutrition and sex seems equally established. " The 

 three kinds of inmates in a bee-hive are known to 

 every one as queens, workers, and drones ; or, as fertile 

 females, imperfect females, and males. What are the 

 factors determining the differences between these three 

 forms ? In the first place, it is believed that the eggs 

 which give rise to drones are not fertilized, while those 

 that develop into queens and workers have the normal 

 history. But what fate rules the destiny of the two 

 latter, determining whether a given ovum will turn out 

 the possible mother of a new generation, or remain at 

 the lower level of a non-fertile working female ? It 

 seems certain that the fate mainly lies in the quantity 

 and quality of the food. Royal diet, and plenty of it, 

 develops the future queens. . . . Up to a certain point 

 the nurse bees can determine the future destiny of 

 their charge by changing the diet, and this in some 

 cases is certainly done. If a larva on the way to be- 

 come a worker receive by chance some crumbs from 

 the royal superfluity, the reproductive function may 

 develop, and what are called ' fertile workers,' to a 

 certain degree above the average abortiveness, result ; 

 or, by direct intention, a worker grub may be reared 

 into a queen bee." ^ 



It is unnecessary to prolong the illustration, for the 

 point it is wished to emphasize is all but in sight. As 

 we have just witnessed, the tendency of abundant 

 nutrition is to produce females, while defective nutri- 

 tive conditions produce males. This means that in so 

 far as nutrition re-acts on the bodies of animals — and 

 1 TheEvolution of Sex, p. 42. See also pp. 41-46. 



