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Darwin Correspondence Project

To Gardeners’ Chronicle   [before 21 July 1855]

In the account compiled by Gärtner (“Beiträge zur Kenntniss der Befruchtung,” p. 75, 1844)1 of the various organs in plants from which nectar is secreted, no mention is made of the stipulæ of the leaves of the common Vetch and Bean. On two occasions I have observed hive bees by the thousands industriously visiting the little dark (but sometimes colourless) glands on the under side of the stipulæ of the Vetch.2 On a hot day, on each gland a minute drop of nectar may be seen almost with the naked eye, and which is sometimes so large as to be just perceptibly sweet. I have seen the hive and another species of bee, a moth, ants, and two kinds of flies, sucking these drops. The hive bee never once even looked at the flowers, but attended solely to the stipulæ; whereas, at the very same time, two kinds of humble bee were sucking the flowers, and never visited the stipulæ. I noticed the hive bees on three successive hot days thus employed; but on the overcast morning of the 12th, after the previous very rainy day, not one was to be seen at mid-day, but numbers of humble bees were sucking the flowers: at 4 o’clock P.M., however, after some hot sunshine, a little glittering drop of nectar studded every gland, and the hive bees, by their mysterious means, had found it out, and were swarming all over the field. The fact of nectar being secreted by an organ quite distinct from the flower (though known in other cases) seems to me of some little interest, as showing that those botanists cannot be correct who believe that nectar is a special secretion for the purpose of tempting insects to visit flowers, and thus aid in their fertilisation. No one probably who has attended to this subject will dispute that insects in very many cases do thus aid the act of fertilisation; but we must, I think, look at the nectar as an excretion which is only incidentally (as is so often done by nature) made use of for a further but most important object. C. Darwin, Down, Farnborough, Kent.

Footnotes

Gärtner 1844. An annotated copy is in the Darwin Library–CUL.
CD’s notes on the habits of bees, dating from 1841, are in DAR 46.2 (ser. 3): 1–53. The particular observations referred to in the letter are recorded in DAR 46.2 (ser. 3): 26–7, the first occasion being in June 1843 and the second given as 26 June 1855. In a further note dated 12 July (DAR 46.2 (ser. 3): 30), CD described observations on hive bees and garden bean flowers.

Summary

Reports on observing hive-bees visiting the leaves of vetch and bean and sucking the minute drops of nectar secreted by the glands on the underside of the stipulae. This phenomenon proves wrong those botanists who believe nectar to be a special secretion for the sole purpose of luring insects to visit flowers and thus to aid in their fertilisation.

Letter details

Letter no.
DCP-LETT-1723
From
Charles Robert Darwin
To
Gardeners’ Chronicle
Sent from
Down
Source of text
Gardeners’ Chronicle and Agricultural Gazette, no. 29, 21 July 1855, p. 487

Please cite as

Darwin Correspondence Project, “Letter no. 1723,” accessed on 13 November 2018, http://www.darwinproject.ac.uk/DCP-LETT-1723

Also published in The Correspondence of Charles Darwin, vol. 5

letter