Note 18 — I. THE DURATION OF LIFE. (continued 2)
Reading edition
These two female ants were still alive on the 25th of September following Sir John Lubbock’s letter, so that they live at least seven years. Cf. ‘Observations on Ants, Bees, and Wasps,’ Part VIII. p. 385; Linn. Soc. Journ. Zool., vol. xv. 1881.
[Sir John Lubbock has kindly given me further information upon the duration of life of these two queen ants. Since the receipt of his letter, the facts have been published in the Journal of the Linnean Society (Zoology), vol. xx. p. 133. I quote in full the passage which refers to these ants:—
‘Longevity.—It may be remembered that my nests have enabled me to keep ants under observation for long periods, and that I have identified workers of Lasius niger and Formica fusca which were at least seven years old, and two queens of Formica fusca which have lived with me ever since December 1874. One of these queens, after ailing for some days, died on the 30th July, 1887. She must then have been more than thirteen years old. I was at first afraid that the other one might be affected by the death of her companion. She lived, however, until the 8th August, 1888, when she must have been nearly fifteen years old, and is therefore by far the oldest insect on record.
‘Moreover, what is very extraordinary, she continued to lay fertile eggs. This remarkable fact is most interesting from a physiological point of view. Fertilization took place in 1874 at the latest. There has been no male in the nest since then, and, moreover, it is, I believe, well established that queen ants and queen bees are fertilized once for all. Hence the spermatozoa of 1874 must have retained their life and energy for thirteen years, a fact, I believe, unparalleled in physiology.’
‘I had another queen of Formica fusca which lived to be thirteen years old, and I have now a queen of Lasius niger which is more than nine years old, and still lays fertile eggs, which produce female ants.’
Both the above-mentioned queens may have been considerably older, for it is impossible to estimate their age at the time of capture. It is only certain (as Sir John Lubbock informs me in his letter) that they must have been at least nine months old (when captured), as the eggs of F. fusca are laid in March or early in April.’ The queens became gradually ‘somewhat lethargic and stiff in their movements (before their death), but there was no loss of any limb nor any abrasion.’ This last observation seems to indicate that queen ants may live for a much longer period in the wild state, for it is stated above that the chitin is often greatly worn, and some of the limbs lost (see pp. 48, 51, and 52).—E. B. P.]