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Darwin Correspondence Project

From Fritz Müller   25 December 1875

My dear Sir,—

In Desterro I met with two young men (M. Charles Wiener, of Paris, and M. Carl Schreiner, from the National Museum of Rio) who, by order of the Brazilian Government, were examining the “Sambaquis” of our province.1 I accompanied them in some of their excursions. These “Sambaquis,” or “Casqueiros,” are hillocks of shells accumulated by the former inhabitants of our coast; they exist in great number, and some of them are now to be found at a distance of several miles from the sea-shore, though originally they were, of course, built near the spot where the shells lived.2 Some are of considerable size; we were told that a Sambaqui on a little island near San Francisco had a height of about 100 metres; but the largest I have seen myself did not exceed 10 or 12 metres. As to the shells of which they are composed, the Sambaquis may be divided into three classes, viz.: (1) Sambaquis, consisting of many different species of bivalve and univalve shells (Venus, Cardium, Lucina, Arca, Ostrea, Purpura, Tritonium, Trochus, &c.), all of which are at present living in the neighbouring sea.3 (2) Sambaquis, consisting almost exclusively of a small bivalve shell, the “Birbigãs” of the Brazilians (Venus flexuosa?), exceedingly common in shallow bays or salt-water lagoas, the bottom of which is of mixed mud and sand.4 (3) Sambaquis, consisting exclusively of a species of Corbula, which I have not yet seen in a living state;5 all the Brazilians also, whom I asked, and who are perfectly acquainted with any edible animal of their marine fauna, are unanimous in affirming that this shell does not live now on our coast. From one of these Corbula-Sambaquis I obtained a specimen of a small Melampus, which I have found living near the mouth of some rivulets, where fresh and salt water are mingling in ever-varying proportions.6 When the lowlands of the Lower Itajahy and some of its tributaries were as yet beneath the level of the sea, they would have formed a large estuary, and here probably the Corbulæ lived. The fragments of human skulls which we found in one of these Corbula-Sambaquis were of truly astonishing thickness, whereas those I have seen from other Sambaquis are hardly thicker than our own. Among the tools which are to be found in the Sambaquis, stone-axes are by far the most frequent. But as M. Wiener will probably soon publish a full account of his researches, I will now no longer dwell on this subject.7

Some time ago I sent to Germany for publication a note on the relation between our Imbauba trees (Cecropia) and the ants which inhabit their hollow stem.8 As there may be some delay in publishing, I will give you a short abstract. Mr. Belt has already stated that the ants farm scale-insects in the cells of the Imbauba stem, and he believes that their presence must be beneficial.9 This is no doubt the case; for they protect the young leaves against the leaf-cutting ants (Oecodoma).10 Now there is a wonderful contrivance by which, as in the case of the “bull’s-horn acacia,” the attendance of the ants at the right time and place is secured.11 At the base of each petiole there is a large flat cushion, consisting of most densely-crowded hairs, and within this cushion a large number of small white pear-like or club-shaped bodies (specimens inclosed) are successively developed, which, when ripe, emerge at the surface of the cushion, like asparagus on a bed, and are then greedily gathered by the ants and carried away to the nest.12 The object of the dense hair-cushion appears to be (1) to secure to the young club-shaped bodies the moisture necesary for their development; and (2) to prevent the ants from gathering the unripe bodies. In most cases it is by honey-secreting glands that the protecting ants are attracted; now Mr Belt observed (“Nicaragua,” p. 225) that the honey-glands on the calyx and young leaves of a Passion-flower were less attractive to the ants than were the scale-insects living on the stems; this would most likely be the case with the Imbauba, and it is probable that the use of the little pear-shaped bodies is to form an attraction stronger than that of the scale-insects, and thus to secure the attendance of the protective ants on the young leaves. As far as I could make out, the club-shaped bodies consist mainly of an albuminous substance.13 The ant colonies are founded by fertilised females, which may be found frequently in the cells of young Imbauba plants. Each internode has on the outside, near its upper end, a small pit where the wall of the cell is much thinner than anywhere else, and where the female makes a hole by which she enters. Soon after this the hole is completely shut again by a luxuriant excrescence from its margins, and so it remains until about a dozen workers have developed from the eggs of the female, when the hole is opened anew from within by these workers. It would appear that the female ants, living in cells closed all around, must be protected against any enemy; but notwithstanding a rather large number of them are devoured by the grub of a parasitic wasp belonging to the Chalcididæ;14 Mr. Westwood has observed that the pupæ of the Chalcididæ exhibit a much nearer approach to the obtected pupæ of the Lepidoptera than is made by any other Hymenoptera” (“Introd. to the Modern Classif. of Insects,” Part XI., p.162).15 Now the pupa of the parasite of the Imbauba ant is suspended on the wall of the cell by its posterior extremity just like the chrysalis of a butterfly.

I hope you will have received a paper on Æglea, a curious Decapod inhabiting the mountain rivulets of our Serra do Mar.16 Lately I obtained a large number of specimens of this Æglea, and among them a female with eggs in an advanced state of development. Thus I was enabled to satisfy myself that, like so many fresh-water and terrestrial animals, the marine allies of which undergo a transformation, our Æglea does not experience any metamorphosis.17

Fritz Müller

Itajahy, St. Catharina, Brazil, Dec. 25, 1875

Footnotes

Destêrro (now Florianópolis) on Santa Catarina Island was the capital of the state of Santa Catarina, Brazil. Sambaqui: Brazilian term for shell mounds, derived from the Tupi language.
Casqueiro: midden (Portuguese). For more on the history of research into these deposits, see Gaspar et al. 2008.
São Francisco do Sul is a town in Santa Catarina at the entrance to the bay of Babitonga. Venus, Cardium, Lucina, Arca, and Ostrea are molluscs of the class Bivalvia (clams or bivalves). Purpura (a synonym of Bolinus), Tritonium (a synonym of Buccinum), and Trochus are molluscs of the class Gastropoda (snails and slugs, formerly known as univalves).
Venus flexuosa is a synonym of Anomalocardia flexuosa (the carib pointed venus or berbigão). ‘Berbigãs’ is probably a mistranscription of Müller’s handwriting.
Corbula is a genus of small saltwater clams of the family Corbulidae.
Melampus is a genus of small air-breathing snails (pulmonate gastropods) of the family Ellobiidae (hollow-shelled snails); Melampus inhabits salt marshes.
Wiener’s article ‘Estudos sobre os sambaquis do sul do Brazil’ (Studies on the sambaquis of south Brazil; Wiener 1876) was published in the first volume of Archivos do Museu Nacional do Rio de Janeiro.
Müller’s article ‘Ueber das Haarkissen am Blattstiel der Imbauba (Cecropia), das Gemüsebeet der Imbaubaameise’ (On the hairy cushions on the petiole of embauba (Cecropia), the vegetable bed of the embauba ant; F. Müller 1876b) was dated 31 October 1875, and published in Jenaische Zeitschrift für Naturwissenschaft on 31 August 1876. Cecropia peltata is the embauba or trumpet tree.
Thomas Belt described ants keeping brown scale-insects (Coccidae) in cells in the hollow trunk of Cecropia in The naturalist in Nicaragua (Belt 1874a, pp. 222–3).
Oecodoma is a synonym of Atta, a genus of leaf-cutter ants in the subfamily Myrmicinae.
Belt had described the small lipid-rich food bodies (now referred to as Beltian bodies) at the tips of leaflets found on species of bull-horn acacias in Belt 1874a, pp. 218–20.
The cushion-like structure at the base of the petiole is now called the trichilium, and the white bodies are now referred to as Müllerian bodies.
Albumin is a class of water-soluble proteins found in animal and plant tissues.
Chalcididae is a family of wasps that are parasitoids of larvae of other insects.
John Obadiah Westwood; see Westwood 1839–40 2: 162. An obtect pupa, which is generally found in Lepidoptera (the family of butterflies and moths), is one in which the wings and legs are fixed to the body and the abdomen is relatively immovable; the pupa is often in an opaque, hard case. Most Hymenoptera (the family of ants, bees, and wasps) have exarate pupae, in which the wings and legs are free and the shape of the insect is visible.
Müller had mentioned his discovery of a new species of Aeglea (a synonym of Aegla, a crustacean genus in the order Decapoda) in his letter to CD of 12 September 1875. His paper ‘Aeglea Odebrechtii n. sp.’ (F. Müller 1876a) was dated late May 1875, and published in Jenaische Zeitschrift für Naturwissenschaft on 15 February 1876. Serra do Mar: mountain range of the sea (Portuguese); a system of mountain ranges in south-eastern Brazil.
Müller believed that other species of Aeglea were marine, but it is an exclusively freshwater genus of the crustacean infraorder Anomura (see letter from Fritz Müller, 12 September 1875 and n. 8).

Bibliography

Westwood, John Obadiah. 1839–40. An introduction to the modern classification of insects; founded on the natural habits and corresponding organisation of the different families. 2 vols. London: Longman, Orme, Brown, Green, and Longman.

Wiener, Charles. 1876. Estudos sobre os sambaquis do sul do Brazil. Archivos do Museu Nacional do Rio de Janeiro 1: 1–20 .

Summary

"Sambaquis", or shell mounds accumulated by former inhabitants of the coast, contain shells of some animals that FM has never seen living.

Ants that live on imbauba trees (Cecropia) are attracted by small bodies at base of each petiole.

Letter details

Letter no.
DCP-LETT-10324
From
Johann Friedrich Theodor (Fritz) Müller
To
Charles Robert Darwin
Sent from
Santa Catharina, Brazil
Source of text
Nature, 17 February 1876, pp. 304–5

Please cite as

Darwin Correspondence Project, “Letter no. 10324,” accessed on 28 January 2022, https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-10324.xml

Also published in The Correspondence of Charles Darwin, vol. 23

letter