Volume 1

Essays upon heredity and kindred biological problems / by August Weismann ; edited by Edward B. Poulton, Selmar Schönland, and Arthur E. Shipley, authorized translation.

  • Shipley A. E. (Arthur Everett), Sir, 1861-1927.
Date:
1891-1892
Catalogue details

Licence: Public Domain Mark

Credit: Essays upon heredity and kindred biological problems / by August Weismann ; edited by Edward B. Poulton, Selmar Schönland, and Arthur E. Shipley, authorized translation. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    rudimentary, while the male possesses perfectly developed wings. The causes which have regulated the length of life in these cases are obvious enough, yet still more striking illustrations are to be found among insects which live in colonies. The duration of life varies with the sex in bees, wasps, ants, and. Termites : the females have a long Hfe, the males a short one ; and there can be no doubt that the explanation of this fact is to be found in adaptation to external conditions of life. The queen-bee—the only perfect female in the hive—lives two to three years, and often as long as five years, while the male bees or drones only live four to five months. Sir John Lubbock has succeeded in keeping female and working ants alive for seven years—a great age for insects^,—while the males only lived a few weeks. These last examples become readily intelligible when we remember that the males neither collect food nor help in building the hive. Their value to the colony ceases with the nuptial flight, and from the point of view of utiHty it is easy to understand why their lives should be so shortBut the case is very different with the female. The longest period of repro- duction possible, when accompanied by very great fertility, is, as a rule, advantageous for the maintenance of the species. It cannot however be attained in most insects, for the capability of hving long would be injurious if all individuals fell a prey to their enemies before they had completed the full period of fife. Here it is otherwise : when the queen-bee returns from her nuptial flight, she remains within the hive until her death, and never leaves it. There she is almost completely secure from enemies and from dangers of ah kinds ; thousands of workers armed with stings protect, feed, and warm her; and in short there is every chance of her living through the full period of a life of normal length. And the case is entirely similar with the female ant. In neither of these insects is there any reason why the advantages which follow from a lengthened period of reproductive activity should be abandoned I Sir John Lubbock has now kept a queen-ant alive for nearly 15 years. See note i on p. 52.—E. B. P.] 2 See Appendix, notes 7 and 9, pp. 60 and 64. ^ Ibid., note 6, p. 59. C 2