The Naturalist in Nicaragua

At Santo Domingo, it continues to bear a succession of fruits during- eight months of the year.

Next to maize, plantains and bananas form the principal sustenance of the natives. The banana tree shoots up its succulent stem, and unfolds its immense entire leaves with great rapidity; and a group of them waving their silky leaves in the sun, or shining ghostly white in the moonlight, forms one of those beautiful sights that can only be seen to perfection in the tropics. There are a great many varieties of them, and they are cooked in into pastry, or eatenmany ways—boiled, baked, made as a fruit. The varieties differ not only in their fruits, but in the colour of their leaves and stems; the natives can distinguish them without seeing the fruit, and have names for each, by which they are known throughout all Central America, Mexico, and Peru. -These names are of Spanish origin; and this fact, together with the absence of any native, Mexican, or Peruvian name for the fruit, inclines me to adopt the opinion of Clavigero, who contends, in opposition to other writers, that the plantain and banana were not known in these countries before the Spanish conquest, but were first brought from the Canaries to Hayti in 15 16, and from thence taken to the mainland. Neither the sugar-cane "^ nor the plantain is given in the list of the indigenous productions of Mexico by the careful and accurate Hernandez. The natives made sugar from the green stems of the maize. Humboldt thinks that some species of plantain were indigenous to

^ The sugar-cane is said never to bear seed in the West Indies, Malaga, India, Cochin China, or the Malay Archipelago.—Darwin's "Animals and Plants under Domestication," vol. ii. p. 169.

America; but it seems incredible that such an important fruit could have been overlooked by the early historians. In the old world the cultivation of the banana dates from the earliest times of which tradition makes mention. One of the Sanscrit names was hhanu—fruit, from w^hich probably the name " banana " was derived.*

Both the plantain and the banana are always propagated from shoots or suckers that spring from the base of the plants; and it is to be remarked that the pineapple and the bread-fruit, that are also universally grown from cuttings or shoots, and have been cultivated from remote antiquity, have in a great measure lost the faculty of producing mature seed. Such varieties could not arise in a state of nature, but are due to selection by early races of mankind, who would naturally propagate the best varieties; and, to do this, seed was not required. As the finest kinds of bananas, pineapples, and breadfruit are almost seedless, it is probable that the nutriment that would have been required for the formation of the seeds has been expended in producing larger and more succulent fruits. We find some varieties of oranges, which also have been cultivated from very early ages, producing fruits without seeds; but as these trees are propagated from seeds, these varieties could not become so sterile as those j ust mentioned. There can be no doubt that the seedless varieties of bananas, bread-fruits, and pineapples have been propagated for hundreds of years; and this fact ought to modify the opinions generally entertained by horticulturists that the life of plants and trees propagated from shoots or cuttings cannot be indefinitely prolonged in that way. Perhaps this may be

• Humboldt's "Aspects of Nature," vol. ii, p. 141.

the case in trees, such as apples, that have come undei' their notice; and the reason that the varieties die out after a certain time, if not reproduced from seed, may be that the vigour of the trees is at last used up by the production of mature seed, but that in the seedless bananas, pineapples, and bread-fruits this does not happen. Figs grow well in Nicaragua, and by many their luscious fruit is preferred to all others. My trees suffered greatly from the attacks of a large and fine longicorn beetle {Twniotcs scalaris, Fab.) which laid its eggs in the green bark, and produced white grubs that mined into the stem. I had to dig down to them with a knife to extricate them and prevent them destroying the young trees. We were surrounded at a short distance by the forest, in which grow many species of wild fig-trees; and this probably was the reason that my trees suffered so much, for at Granada the fig-gowers were not troubled with this insect.

The grenadilla is the fruit of one of the passion-fiowers {Fassijiora quadrangulcms), and is shaped like a large oblong apple, which it also resembles in perfume. It makes fine tarts and puddings, being somewhat like the gooseberry in taste. I had much diflficulty in pre-serving it from being eaten by small forest rats that came out of the woods, where they had already been accustomed to eat the wild fruit of this climber.

The moist, warm climate seemed to suit the papaw tree, as it grew with great vigour, and produced very large and fine melon-like fruits. The green fruits are excellent for making pastry, if flavoured with a little lime-juice.

In vegetables, I gi*ew three species of sweet potatoes yellow, purple, and white skinned, and which differ also in their leaves and flowers; cabbages, kidney-beans, pumpkins, yuccas {Jatropha manihot), queqnisque (a species of arum, Colocasia esctdenta), lettuces, tomatoes, capsicums, endives, parsley, and carrots.

The climate was too damp to grow onions; neither could I succeed with peas, potatoes, or turnips. Scarlet runners [Phascolns midtijionis) grew well, and flowered abundant!}^, but never produced a single pod. Darwin has shown that this flower is dependent, like many others, for its fertilisation upon the operations of the busy humble-bee, and that it is provided with a wonderful mechanism, by means of which its pollen is rubbed into the head of the bee, and received on the stigma of the next plant visited.* There are many humble-bees, of different species from ours, in tropical America; but none of them frequented the flowers of the scarlet runner, and to that circumstance we may safely ascribe its sterility. An analogous case has been long known. The vanilla plant ( Vanilla planifolia) has been introduced from tropical America into India, but though it grows well, and flowers, it never fruits without artiticial aid. It is the same in the hothouses of Europe. Dr. Morren, of Liege, has shown that, if ai'tificially fertilised, every flower will produce fruit; and ascribes its sterility to the absence, in Europe and India, of some insect that in America carries the pollen from one flower to another. -f- When those interested in the acclimature of the natural

• "Gardener's Chronicle/' Oct. 24, 1857, and Ndv. 14, 1858; also T. H. Farrer, in "Annals of Natural History," Oct. 1868. f Taylor's "Annals of Natural History," vol. iii. p. I.

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productions of one country on the soil of some distant one, study the mutual relations of plants and animals, they will find that in the case of many plants it is important that the insects specially adapted for the fertilisation of their flowers should be introduced with them. Thus, if the insect or bird that assists in the fertilisation of the vanilla could be introduced into and would live in India, the growers of that plant would be relieved of much trouble, and it might be thoroughly naturalised. Judging from my experience, it would be useless to attempt the acclimature of the scarlet-runner bean in Chontales unless the humble-bee were also introduced.

Caterpillars, plant-lice, bugs, and insect pests of all kinds were numerous, and did much harm to my garden but the greatest plague of all were the leaf-cutting ants, and I had to wage a continual warfare against them. During this contest I gained much information regarding their habits, and was successful in checking their ravages, and I shall occupy the remainder of this chapter with an account of them.

all travellers in tropical Leaf-cutting Ants.—Nearly America have described the ravages of the leaf-cutting ants {CEcodoma); their crowded, well-worn paths through the forests, their ceaseless pertinacity in the spoliation of the trees—more particularly of introduced species which are stripped bare and ragged, with the midribs and a few jagged points of the leaves only left. Many a young plantation of orange, mango, and lemon trees has been destroyed by them. Again and again have I been told in Nicaragua, when inquiring why no fruit-trees were grown at particular places, " It is no use planting

them; the ants eat them up." The first acquaintance a stranger generally makes with them is on encountering their paths on the outskirts of the forest crowded with the ants; one lot carrying off the pieces of leaves, each piece about the size of a sixpence, and held up vertically between the jaws of the ant; another lot hurrying along in an opposite direction empty-handed, but eager to get loaded with their leafy burdens. If he follows this last division, it will lead him to some young trees or shrubs, up which the ants mount; and then each one, stationing itself on the edge of a leaf, commences to make a circular cut, with its scissor-like jaws, from the edge, its hinder feet being the centre on which it turns. When the piece is nearly cut off, it is still stationed upon it, and it looks as though it would fall to the ground with it; but, on being finally detached, the ant is generally found to have hold of the leaf with one foot, and soon righting itself, and arranging its burden to its satisfaction, it sets off at once on its return. Following it again, it is seen to join a throng of others, each laden like itself, and, without a moment's delay, it hurries along the well-worn path. As it proceeds, other paths, each thronged with busy workers, come in from the sides, until the main road often gets to be seven or eight inches broad, and more thronged than the streets of the city of London.

After travelling for some hundreds of yards, often for more than half a mile, the formicarium is reached. It consists of low, wide mounds of brown, clayey-looking earth, above and immediately around which the bushes have been killed by their buds and leaves having been persistently bitten off as they attempted to grow after their first defoliation. Under his'h trees in the thick

forest the ants do not make their nests, because, I believe, the ventilation of their underground galleries, about which they are very particular, would be interfered with, and perhaps to avoid the drip from the trees. It is on the outskirts of the forest, or around clearings, or near wide roads that let in the sun, that these formicariums are generally found. Numerous round tunnels, varying from half an inch to seven or eight inches in diameter, lead down through the mounds of earth; and many more, from some distance around, also lead underneath them. At some of the holes on the mounds ants will be seen busily at work, bringing up little pellets of earth from below, and casting them down on the ever-increasing mound, so that its surface is nearly always fresh and new-looking. Standing near the mounds, one sees from every point of the compass ant-paths leading to them, all thronged with the busy workers carrying their leafy burdens. As far as the eye can distinguish their tiny forms, troops upon troops of leaves are moving up towards the central point, and disappearing down the numerous tunnelled passages. The outgoing, empty - handed hosts are partly concealed amongst the bulky burdens of the incomers, and can only be distinguished by looking closely amongst them. The ceaseless, toiling hosts impress one with their power, and one asks—What forests can stand before such invaders? How is it that vegetation is not eaten off the face of the earth? Surely nowhere but in the tropics, where the recuperative powers of nature are immense and ever active, could such devastation be withstood.