Insectivora

“ Kidnapping is not by any means confined to either humanity or the fairy people.”
“Monster,” said the Thin Woman in a deep voice, “will you listen to me?”
“I will not,” said the Philosopher. “Many of the insectivora also practice this custom. Ants, for example, are a respectable race living in well-ordered communities. ”

“ As an additional indication of the distinctness and isolation of the Neotropical region from all others, and especially from the whole Eastern Hemisphere, we must say something of the otherwise widely distributed groups which are absent. Among mammalia we have first the order Insectivora, entirely absent from South America, though a few species are found in Central America and the West Indies; the Viverridæ or civet family is wholly wanting, as are every form of sheep, oxen, or antelopes ”

“ INSECTIVORA, an order of non-volant placental mammals of small size, with a dentition adapted to an insect-diet. In nearly all cases these creatures are nocturnal, and the majority are terrestrial, many burrowing in the ground, although a few are arboreal and others aquatic. They have plantigrade or partially plantigrade feet, that is to say, they apply the whole or the greater portion of the soles to the ground when walking; and there are generally five toes, each terminating in a claw, and the first never being opposable to the others in either the fore or hind limb. ”

“ Hardly less remarkable is the absence of many wide-spread groups. With the exception of one genus in the West Indian islands and a Sorex which reaches Guatemala and Costa Rica, the Insectivora are wholly wanting; as is also the extensive and wide-spread family of the Viverridæ. It has no oxen or sheep, and indeed no form of ruminant except deer and llamas; neither do its vast forests and grassy plains support a single form of non-ruminant ungulate, except the tapir and the peccary.
Birds.—In birds, the Neotropical region is even richer and more isolated. ”

“ The Copris enjoys in her underground home a rare privilege for an insect: the pleasure of knowing her family. She hears her grubs scratching at the shell to obtain their liberty; she is present at the bursting of the nest which she has made so carefully. And when the little captive, stiffening his legs and humping his back, tries to split the ceiling that presses down on him, it is quite possible that the mother comes to his assistance by making an assault on the nest from the outside. Being fitted by instinct for repairing and building, why should she not also be fitted for demolishing? ”

“ Who can explain the origin of the sexes? What is the cause that determines that one individual in a brood of Stylops, for example (Fig. 184, male; Fig. 185, grub-like female in the body of its host) , shall be but a grub, living as a parasite in the body of its host, while its fellow shall be winged and as free in its actions as the most highly organized insect? It is no less mysterious, because it daily occurs before our eyes. So perhaps none the less mysterious, and no more discordant with known natural laws may the law that governs the origin of species seem to those who come after us. ”

“ But if in our diagram we suppose, for instance, the stigma to be seated at the bottom of a deep cavity, low down in the column, or the anther to be seated higher up, or the pedicel of the rostellum to slope more upwards, &c.—all of which contingencies occur in various species,—in such cases, an insect with a pollinium attached to its head, if it flew to another flower, would not place the pollen-masses on the stigma, unless their position had become greatly changed after attachment. ”

“ America is anything but considerate when she sends us her entomological pests. We owe the Phylloxera to America; the Phylloxera, that calamitous insect against which our vine-growers wage incessant war: and to-day she is sending us the haricot-weevil, which threatens to be a plague of the future. A few experiments gave me some idea of the peril of such an invasion.
For nearly three years there have stood, on my laboratory table, some dozens of jars and bottles covered with pieces of gauze which prevent escape while permitting of a constant ventilation. These are the cages of my menagerie. ”

“ And even if we grant, what I consider inadmissible, a Sphex catching flies, other difficulties crowd in. It is now proved on evidence that the burrowing Hymenoptera do not carry dead bodies to their larvæ, but merely prey benumbed and paralysed. What, then, is the meaning of this prey whose head, abdomen, and wings are cut off? The torso carried away is but a [125] portion of a corpse that would infect the cell and be useless to the larva, not yet to be hatched for several days. It is perfectly clear that Darwin’s insect was not a Sphex, strictly speaking. ”

“ But I must own that I have never yet beheld the deadly manœuvre, thanks to the solitary life of this Sphex.
When a number of burrows are made and then provisioned on some common ground, one has only to wait there to see now one insect return from the chase, now another, with her prey, and it is easy to substitute a live victim for the one sacrificed, renewing the experiment at will. Besides, the certainty that the subjects for experiment will not fail when wanted allows everything to be prepared beforehand, while with S. occitanica these conditions of success do not exist. ”

“ We noted, in passing, that the young insect is free to lire its own lire and to develop structures suited to its own purposes under one proviso, which is that it must even- tually revert to the form of the adult of its species. At the period of transformation, the particular characters of the young must be discarded, and those of the adult must be developed. Insects such as the grasshoppers, the katydids, the roaches, the dragonflies, the aphids, and the cicadas ap- pear in the adult form when the young sheds its skin for the last rime. ”

“ The apple that is rotten before it is ripe is an insect's victim, and, if the plums fall green and untimely in scores upon the ground, once more it is an insect that has been at work among them. Talk about German spies! Had German spies gone to the insect world for a lesson, they might not have been the inefficient bunglers they showed themselves to be. At the same time, most of us hate spies and insects for the same reason. We regard them as noxious creatures intruding where they have no right to be, preying upon us and giving us nothing but evil in return. ”

“ So great and rapid are the powers of assimilation of the Insect, so prodigious its capacity for multiplication, that the Mammal would not be able to compete with it were it not that the great horde of six-legged creatures has divided itself into two armies, one of which destroys the other. The parasitic Hymenoptera are chiefly occupied in destroying the tribes of vegetarian Insects; the parasites do this by the simple and efficient device of dwelling in the bodies of their hosts and appropriating the nutriment the latter take in. ”

“ If it honours their kraal with a visit, the inhabitants assemble round it with transports of devotion, as if the Lord of the Universe was come among them. If the insect happens to alight on a Hottentot, he is looked upon as a man without guilt, and distinguished and reverenced as a saint and the delight of the Deity ever after. They declared to me that if this deified insect had been killed, all their cattle would certainly have been destroyed by wild beasts, and they themselves, every man, woman, and child of them, brought to a miserable end.”—Kolben, volume one, page 99. ”

“ When an insect alights on the central disc, it is instantly entangled by the viscid secretion, and the surrounding tentacles after a time begin to bend, and ultimately clasp it on all sides. Insects are generally killed, according to Dr. Nitschke, in about a quarter of an hour, owing to their tracheae being closed by the secretion. If an insect adheres to only a few of the glands of the exterior tentacles, these soon become inflected and carry their prey to the tentacles next succeeding them inwards ”

“ The insect has departed in the night, having finished its business there. It is a nomad, a night-walker, which leaves its dwelling without regret and easily acquires another. Often, on the other hand, the insect will be found at the bottom of the burrow; sometimes a male, sometimes a female, but always alone. The two sexes, equally zealous in excavating their burrows, work apart without collaboration. This is no family mansion for the rearing of offspring; it is a temporary dwelling, made by each insect for its own benefit. ”

“ These contents, which lie hidden under the ceiling, are invisible; and the insect can derive its information only from the outside of the nest, which varies in the different species. We should therefore have to admit the existence of a particular power of discrimination, a sort of discernment of the species, which is recognized as large or small from the outward aspect of its house. I refuse to go to this length in my conjectures, not that instinct seems to me incapable of such feats, but because of the particulars obtained from the three-horned Osmia and the two mason bees. ”

“ If impatience get the better of us, we can open them at the end of July or in August. The insect is then in the nymphal stage; and it is easy, under this form, to distinguish the two sexes by the length of the antennae, which are larger in the males, and by the glassy protuberances on the forehead, the sign of the future armour of the females. Well, the small cocoons, those in the narrow front cells, with their scanty store of provisions, all belong to males; the big cocoons, those in the spacious and well-stocked cells at the back, all belong to females. ”

“ The main object however of the present section being to show that a considerable amount of power is due to isolation itself, in regulating (after a long series of ages) the outward aspect of the insect tribes, it is not strictly necessary that we should so rigidly insist on deterioration of size as one of its primary consequences,—since (whether it be so or not) we are merely concerned here to demonstrate, that its influence, in some shape or other, is absolute and real. ”

“ The insect parasites and predators of other insects in general comprise a class of insects that are most beneficial to us by reason of their large-scale destruction of species injurious to our crops. But, unfortunately, parasites as a class do not respect our classification of other creatures into harmful and useful species. ”

“ I am profoundly incredulous of so much self-sacrifice, and my incredulity is borne out by all which I have seen during many long years, not in collection boxes, but on the spots where the Scarabæi work. Outside of the cares of maternity—cares in which it almost always shows itself admirable, the Insect—unless, indeed, it lives in society like bees and ants and some others—thinks and cares for nothing but itself. ”

“ Most insectivores will only eat live insects. If it is hard to get live insects, you may be able to get the lizard to accept dead food by offering it on the end of a thin wire. By moving the insect, the lizard will think it is alive, and often will grasp the food. Insectivores require a large amount of food, and the food should be varied: don’t feed all meal worms, or all crickets, but try to offer a variety of insects. ”

“ It is not at all necessary to show that the socialism of insects has advanced along these lines—their greater fertility allowing of a still more remarkable specialisation—in order to make out a case for the possibility, or even likelihood, of its hereafter doing so in the case of some birds. There are insect communities, however, composed of males and fertile females, or of the latter only, that may be compared, without much violence, to those of terns or weaver-birds. ”

“ The itch insect (Sarcoptes scabiei, Fig. 150) was first recognized by an Arabian author of the twelfth century, as the cause of the disease which results from its attacks. The body of the insect is rounded, with the two hind pair of feet rudimentary and bearing long hairs. It buries itself in the skin on the more protected parts of the body, and by its punctures maintains a constant irritation. Other species are known to infest the sheep and dog. ”

“ When its depredations cover a somewhat extensive group, how does the insect manage to recognize the genera, the species composing her allotted portion and to distinguish them from the rest with an assured vision which the inventory of her burrows proves never to be at fault? ”

“ If a non-social and relatively unintelligent insect is capable of thus far consciously adjusting its actions, then it seems a reasonable supposition that in a community of social insects there has arisen a mass of experience and usage into which each new individual is initiated ”

“ While she was within I have pushed the prey rather farther off, and have always obtained precisely the same result as in the case of the huntress of crickets. In both Sphegidæ there was the same persistence in plunging into their burrows before dragging down their prey. We must recollect that S. flavipennis does not always allow herself to be duped by my trick of withdrawing the insect. There are elect tribes among them,—strong-minded families,—who after a [176] while find out the tricks of the experimenter, and know how to baffle them. But these revolutionaries capable of progress are the few ”