Sex differentiation and development : proceedings of a symposium held at the Royal Scoiety of Medicine, Wimpole Street, London, on 10 and 11 April 1958 / edited on behalf of the Society for Endocrinology by C.R. Austin.

  • Symposium on Sex Differentiation and Development (1958 : London, England)
Date:
1960
Catalogue details

Licence: Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)

Credit: Sex differentiation and development : proceedings of a symposium held at the Royal Scoiety of Medicine, Wimpole Street, London, on 10 and 11 April 1958 / edited on behalf of the Society for Endocrinology by C.R. Austin. Source: Wellcome Collection.

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    SEX AND CASTE IN THE HONEYBEE 5 the quantities of the essential nutrients supphed to and consumed by worker and queen larvae, respectively. He pointed out that, until about the 3rd day of life, all larval honeybees in prosperous colonies receive an excess of food, but that, subsequently, while the queen larvae in their large cells continue to be supphed with more food than they can eat, the worker larvae in much smaller cells only receive relatively small quantities of food from time to time. The result is that the queen and worker larvae grow at approximately the same rate for the first day or two, but subsequently, whereas the queen larva, surrounded by an abundance of food, continues to grow rapidly, the much more frugally fed worker larva grows more slowly. Haydak [1943] pointed out that, even after her cell has been sealed, a queen larva continues to feed upon the surplus of brood food in the bottom of her cell, whereas a worker larva, having no such source of food, cannot feed any more once her cell has been sealed, and actually loses weight. In order to test his hypothesis, Haydak removed the larvae from queen cells that were either just about to be sealed or had just been sealed, so that they could not eat any more food. Most of the larvae that he treated in this way died in the pupal stage, but he reported that seven of these pupae possessed worker rather than queen charac¬ teristics, while several others were intermediate in form between queens and workers. Nine adults were obtained, all except one of which were normal queens, the exceptional individual being intermediate between a queen and a worker. Haydak reported that the average initial weight of those of the larvae that developed into queens was 14% greater than that of larvae developing into individuals with worker or intermediate characteristics. From Haydak's results, it certainly appears likely that continuous liberal feeding of those larvae that are destined to become queens plays an important role in their differen¬ tiation. However, von Rhein [1933] who, in the laboratory, fed female larvae very liberally with brood food taken from queen cells, failed to obtain the queens one would have expected if Haydak's hypothesis were correct. Indeed, his failure to produce queens in this way led von Rhein to suppose that some unstable, differentiating substance is fed by worker bees to those larvae that are destined to become queens, and that this fugitive substance had either been destroyed (or, perhaps, lost during storage) in the brood food he took from queen cells and fed to his larvae. Simpson [1957] has also shown that abundant feeding alone, even when it is carried out by worker bees themselves, is insufficient to cause a female larva to develop into a queen. Recently, Weaver [1955, 1957] has reported the results of some experiments similar to those of von Rhein [1933], in which he fed young female larvae, taken from worker cells, on abundant brood food freshly collected from queen cells containing larvae of approximately the same ages as the experimental ones, bi these circumstances, queens were produced. On the other hand, when similar larvae were fed abundantly with brood food collected from queen cells and stored for some time, only workers were produced. These results clearly fail to support Haydak's conclusion, as the experimental larvae were continuously supplied with a superfluity of food so that quantitative starvation could not have been the determining mechanism. On the other hand, they
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