Gives observations on the habits of the "agricultural ant" of Texas.
Long Point. Texas.
Charles Darwin. M.A., | Down, Bromley, Kent. England.
While in my little, quiet office this evening, carefully examining your valuable work
``on the origin of species'' &
In my journal of observations I find many cases, applicable to your theory of natural selection, but in my present state of mind, I feel more inclined to state some of my observations on the agricultural successes of one of our many species of Texas ants. It may interest you some. It cannot injure. Consider it. If you like it, and want more, write.
The species of Formica, which I have named Agricultural; is a large brownish red ant, dwells in paved cities, is a farmer, thrifty and healthy; is delligent and thoughtful, making suitable and timely arrangements for the changing seasons; in short, he is endowed with capacities sufficient to contend with much skill and ingenuity; and untiring patience, with the varying exigencies with which he may encounter in the life conflict.
When selects a situation upon which to locate a city, if it is on ordinarily dry land, he bores a hole, around which he elevates the surface three, sometimes six inches; forming a low, circular mound; with a very gentle inclination from the center to its outer limits; which on an average is three to four feet from the entrance. But if the location is made on a low, or flat wet land, liable to inundation, though the ground may be perfectly dry at the time he does the work, he nevertheless elevates his mound in the form of a pretty sharp cone, to the hight of fifteen to twenty inches, sometimes even more, having the entrance near the apex. Around this, and its the same case with the upland cities, he clears the ground of all obstructions, levels and smoothes the surface to the distance of three or four feet from the gate of the city, giving it the appearance of a handsom pavement, as it really is. Upon this pavement not a spine of any green thing is permitted to grow, except a single species of grain bearning grass. Having planted it in a circle around, and two or three feet from the center of the mound, he nurses and cultivates it with constant care cutting away all other grasses and weeds that may spring up amongst it, and all round outside of the farm circle to the extent of one or two feet. The cultivated grass grows luxuriently, producing a heavy crop of small, white, flinty seeds, which under the microscope very much resembles the rice of commerce. When it gets ripe it is carefully harvested, and carried by the workers, chaff and all into the grainery cells, where it is divested of the chaff and packed away; the chaff is taken out and thrown beyond the limits of the pavement.
During protracted spells of wet weather, it sometimes happens that their provision stores become damp, and liable, as they are invariably seeds of some kind, to sprout and spoil. If this has occurred, the first fair day after the rain, they bring out the damp and damaged stores expose them to the sun till they are dry, when they carry back and pack away all the sound seeds, leaving all that are sprouted to waste.
In a peach orchard, not far from my residence, is a considerable elevation, on the top
of which, there is an extensive bed of rock. In the sand beds overlying portions of this
rock, are five cities of the agricultural ants. They are evidently quite ancient cities,
and may have occupied this elevated rock for thousands of years. My term of observations
on their manners and customs, has been limited to the time the cattle, by the orchard
enclosure, have been kept away from their Rice farms 12 years. Those cities
which are outside of the inclosures, as well as the protected cities, are, at the proper
season, invariably planted with the ant Rice. And we accordingly see it sprining up, in
the farm circle about the first of November, every year. Of late years however, since
the numbers of farms and cattle have greatly increased, and the cows are eating out the
grass much closer than formerly, preventing the ant farms and every where else from
maturing seeds, I notice that the agricultural ants—but no other species of
ant—are locating their cities along the turn rows in the fields, walks in the
gardens, inside about the gates &
There can be no doubt of the fact, that the peculiar grain bearing grass, mention above, is intentionally planted; in farmer like manner, the ground upon which it stands, is carefully divested of all other grasses and weeds during the time of its growth, and that when it is ripe and the grain taken care of, they cut away the dry stubble, and carrying it out of the way, leave the pavement unincumbered until the insuing autumn, when the same ant rice, and in the same circle appears again, receiving the same agricultural attention as did the previous crop, and so on, year after year, as I know to be the case, in all situations where they are protected from graminivorous animals.
I have no theological clique to curb the play of my mind such as it is, nor is it fettered to the cosmogony of any priestly doccuments, ancient or modern; and, so, I may here undisturbed, suggest that it may not exceed a few short millions of years, since this now, bold, healthy, thrifty, city paving, agricultural species of emmet, belonged perhaps, to a feeble variety of hunters and herders, who, in the struggle for existance, were entirely dependent on the natural droppings of the seeds of vegetation, such insects and worms as their hunters could master, and the Aphis for subsistence. Then the ``struggle for existence'' was difficult, alike to all the communities of that variety. At a certain period however, and near the gates of a particular city, a seed of the favourite grain bearing grass by carelessness had been left,—or if you like, and it does not overreach the bounds of their intelligence in my estimation, some thoughtful ant planted it there for experiment.— Be this as it may, the seed sprouted and grew up to a flourishing tuft, producing a bountiful crop of the favourite Rice; which in due time was, by the inhabitants of the city, carefully harvested. This, in addition to what had been collected from the country around, smartly enlarged their stores of food, whereby greater numbers would survive the winter, in greater strength they would be able to compete in the struggle for life, during the coming season; again a few plants of the rice would be tried; the results of course, would be encouraging; and thus by little and little the agricultural habit gradually obtained. By the good effects of less labour and more food, the population of the city were steadily increasing in form, size, vigor, and numbers. And so, the slow, but sure modefying principles and powers of natural selection, rolled on, gathering as it progressed through an unimaginable series of ages until they found themselves occupying a great paved city, surrounded by a stately farm and crowded with a lusty, warlike population. colony after colony had gone out, and, carrying with them the agricultural habit, they had dotted the far off regions with their robust, dominant, farm cities; all so changed in strength, habits and general appearance, that they bore no similarity to the type of the original variety from which they had branched.— But there were none of the parent variety to be found for comparrison. they were extinct. Had been exterminated by the forces, under favorable conditions, of Natural Selection. The no-cornmaking, pastoral Abel, had been overcome,—rooted out by the vigorous, prolific, Agricultural Cain. Thus, the transitional link between this, now distinct and wonderfully developed species, and probably, the well digging Species, who are about the same size and colour, subsisting on the foilage of vegetation, are, to Science forever lost.
I might ennumerat twenty odd Species of Texas ants. The two species I have alluded to
are however, the most interesting. But I must abstain from any attempt at giving you
even a glimpse of the history of their stupendeous public works, governmental systems;
laws, civil and military; slaves, prisoners, distructive wars &
Old men, like myself, can do but little of anything, and ought not to promise themselves much; but I think I will, sometime when I feel in a proper condition for it, write out a short account of what I have seen during the past twelve years, amongst our abundant Animal and vegetable fossils; our insect kingdom and our blooming prairies.
I am a native American, born in the smoke of our first revolution; was raised and have always been a dweller in the wild border countries, and now, I think the chances are pretty good for me to make my exit in the turmoil and smoke of another revolution.
Most Respectfully. | Gideon Lincecum.
- f1 3035.f1Lincecum was an American physician and self-taught naturalist who practised medicine in Texas. He refers to E. Darwin 1803, a work published posthumously. American editions were issued in 1804 and 1808.
- f2 3035.f2Lincecum had been studying several local species of ants. Apparently unaware of their scientific classification, he catalogued and named over fifty species himself (Burkhalter 1965, p. 208).
- f3 3035.f3No letters from CD to Lincecum have been located, but see the letter from Gideon Lincecum, 4 March 1861 (Correspondence vol. 9).
- f4 3035.f4CD subsequently sent the letter to George Busk, zoological secretary of the Linnean Society of London (see Correspondence vol. 9, letter to George Busk, 5 April ). A section of the letter, from the beginning of the third paragraph to the end of the sixth, was read at a meeting of the society on 18 April 1861 (Proceedings and Journal of the Linnean Society 6 (1861): 29). The letter was corrected and edited, possibly by Busk.
- f5 3035.f5Lincecum was born in 1793. He refers to the political turmoil in the United States over the question of slavery and states' rights that threatened to dissolve the union.