Brillat-Savarin, when pronouncing his famous maxim, "Tell me what you eat and I will tell you what you are," certainly never suspected the signal confirmation which the entomological world would bestow upon his saying. Our gastrosopher was speaking only of the culinary caprices of man rendered fastidious by the sweets of life; but he might, in a more serious department of thought, have given his formula a wider and more general bearing and applied it to the dishes which vary so greatly according to latitude, climate and customs; he might above all have taken into his reckoning the harsh realities suffered by the common people, when perhaps his ideal of moral worth would have been found in a platter of chick-peas oftener than in a pot of pate de foie gras. No matter: his aphorism, the mere whimsical sally of an epicure, becomes an imperious truth if we forget the luxury of the table and look into what is eaten by the little world which swarms around us.
To each its mess. The cabbage Pieris consumes the pungent leaves of the Cruciferae as the food of her infancy; the Silkworm disdains any foliage other than that of the mulberry-tree. The Spurge Hawk-moth requires the caustic milk-sap of the tithymals: the Corn-weevil the grain of wheat; the Pea-weevil, the seeds of the Leguminosae; the Balaninus (A genus of Beetles including the Acorn-weevil, the Nut-weevil and others.—Translator's Note.) the hazel-nut, the chestnut, the acorn; the Brachycera (A division of Flies including the Gad-flies and Robber-flies.—Translator's Note.) the clove of garlic. Each has its diet, each its plant; and each plant has its customary guests. Their relations are so precise that in many cases one might determine the insect by the vegetable which supports it, or the vegetable by the insect.
If you know the lily, you may name as a Crioceris the tiny scarlet Scarabaeid that inhabits it and peoples its leaves with larvae which keep themselves cool beneath an overcoat of ordure. (For the Lily-beetle, or Crioceris merdigera, cf. "The Glow-worm and Other Beetles," by J. Henri Fabre, translated by Alexander Teixeira de Mattos: chapters 16 and 17.—Translator's Note.) If you know the Crioceris, you may name as a lily the plant which she devastates. It will not perhaps be the common or white lily, but some other representative of the same family—Turk's cap lily, orange lily, scarlet Martagon, lancifoliate lily, tiger-spotted lily, golden lily—hailing from the Alps or the Pyrenees, or brought from China or Japan. Relying on the Crioceris, who is an expert judge of exotic as well as of native Liliaceae, you may name as a lily the plant with which you are unacquainted and trust the word of this singular botanical master. Whether the flower be red, yellow, ruddy-brown or sown with crimson spots, characteristics so unlike the immaculate whiteness of the familiar flower, do not hesitate, adopt the name dictated by the Beetle. Where man is liable to mistake the insect is never mistaken.
This insect botany, a cause of such grievous tribulations, has always impressed the worker in the fields, who for all that, is a very indifferent observer. The man who was the first to see his cabbage-plot devastated by caterpillars made the acquaintance of the Pieris. Science completed the process, in its desire to serve a useful purpose or merely to seek truth for truth's sake; and to-day the relations between the insect and the plant form a collection of records as important from the philosophical as from the practical, agricultural point of view. What is much less familiar to us, because it touches us less nearly, is the zoology of the insect, that is to say, the selection which it makes, to feed its larva, of this or that animal species, to the exclusion of others. The subject is so vast that a volume were not sufficient to exhaust it; besides, data are lacking in the vast majority of cases. It is reserved for a still very distant future to raise this point of biology to the level already reached by the question of vegetable diet. It will be enough if I contribute a few observations scattered through my writings or my notes.
What does the Wasp addicted to a predatory life eat, of course in the larval state? Now, to begin with, we see natural sections which adopt as their prey different species of one and the same order, in one and the same group. Thus the Ammophilae hunt exclusively the larvae of the night-flying Moths. This taste is shared by the Eumenes, a very different genus. (Cf. "The Mason-wasps" by J. Henri Fabre, translated by Alexander Teixeira de Mattos: chapter 1.—Translator's Note.) The Spheges and Tachytes are addicted to Orthoptera; the Cerceres, apart from a few exceptions, are faithful to the Weevil; both the Philanthi and the Palari capture only Hymenoptera; the Pompili specialize in hunting the Spider; the Astata revels in the flavour of Bugs; the Bembeces want Flies and nothing else; the Scoliae enjoy the monopoly of the Lamellicorn-grubs; the Pelopaei favour the young Epeirae (Or Garden Spiders. Cf. "The Life of the Spider": chapters 9 to 14 and appendix.—Translator's Note.), the Stizi vary in opinion: of the two in my neighbourhood, one, S. ruficornis, fills her larder with Mantes and the other, S. tridentatus, fills it with Cicadellae (Cf. "The Life of the Grasshopper": chapter 20.—Translator's Note.); lastly, the Crabronidae (Any Flies akin to the House-fly.—Translator's Note.). levy tribute upon the rabble of the Muscidae. (Hornets.—Translator's Note.)
Already you see what a magnificent classification of these game-hunters might be made with a faithfully listed bill of fare. Natural groups stand out, characterized merely by the identity of their victuals. I trust that the methodical science of the future will take account of these gastronomic laws, to the great relief of the entomological novice, who is too often hampered by the snares of the mouth-parts, the antennae and the nervures of the wings. I call for a classification in which the insect's aptitudes, its diet, its industry and its habits shall take precedence of the shape of a joint in its antennae. It will come; but when?
If from generalities we descend to details, we shall see that the very species may, in many instances, be determined from the nature of its victuals. The number of burrows of Philanthus apivorus which I have inspected since I have been rummaging the hot roadside embankments, to enquire into their population, would seem hyperbolical were I able to state the figures. (For the Bee-eating Philanthus cf. Chapter 10 of the present volume.—Translator's Note.) They must amount, it seems to me, to thousands. Well, in this multitude of food-stores, whether recent or ancient, uncovered for a purpose or encountered by chance, I have not once, not as often as once, discovered other remains than those of the Hive-bee: the imperishable wings, still connected in pairs, the cranium and thorax enveloped in a violet shroud, the winding-sheet which time throws over these relics. To-day as when I was a beginner, ever so long ago; in the north as in the south of the country which I explored; in mountainous regions as on the plains, the Philanthus follows an unvarying diet: she must have the Hive-bee, always the Bee and never any other, however closely various other kinds of game resemble the Bee in quality. If, therefore, when exploring sunny banks, you find beneath the soil a small parcel of mutilated Bees, that will be enough to point to the existence of a local colony of Philanthus apivorus. She alone knows the recipe for making potted Bee-meat. The Crioceris was but now teaching us all about the lily family; and here the mildewed body of the Bee tells us of the Philanthus and her lair.
Similarly the female Ephippiger helps us to identify the Languedocian Sphex: her relics, the cymbals and the long sabre, are the unmistakable sign of the cocoon to which they adhere. The black Cricket, with his red-braided thighs, is the infallible label of the Yellow-winged Sphex; the larva of Oryctes nasicornis tells us of the Garden Scolia as certainly as the best description; the Cetonia-grub proclaims the Two-banded Scolia and the larva of the Anoxia announces the Interrupted Scolia.
After these exclusive ones, who disdain to vary their meals, let us mention the eclectics, who, in a group which is generally well-defined, are able to select among different kinds of game appropriate to their bulk. The Great Cerceris (Cerceris tuberculata. Cf. "The Hunting Wasps": chapters 2 and 3.—Translator's Note.) favours above all Cleonus ophthalmicus, one of the largest of our Weevils; but at need she accepts the other Cleoni, as well as the kindred genera, provided that the capture be of an imposing size. Cerceris arenaria (Cf. idem: chapter 1.—Translator's Note.) extends her hunting-grounds farther afield: any Weevil of average dimensions is to her a welcome capture. The Buprestis-hunting Cerceris adopts all the Buprestes indiscriminately, so long as they are not beyond her strength. The Crowned Philanthus (P. coronatus, FAB.) fills her underground warehouses with Halicti chosen among the biggest. (Cf. "Bramble-bees and Others" by J. Henri Fabre, translated by Alexander Teixeira de Mattos: chapters 12 to 14.—Translator's Note.) Much smaller than her kinswoman, Philanthus raptor, LEP., stores away Halicti chosen among the less large species. Any adult Acridian approaching an inch in length suits the White-banded Sphex. The various tidae of the neighbourhood are admitted to the larder of Stizus ruficornis and of the Mantis-hunting Tachytes on the sole condition of being young and tender. The largest of our Bembeces (B. rostrata, FAB., and B. bidentata, VAN DER LIND (For the Rostrate Bembex and the Two-pronged Bembex, cf. "The Hunting Wasps": chapter 14.—Translator's Note.)) are eager consumers of Gad-flies. With these chief dishes they associate relishes levied indifferently from the rest of the Fly clan. The Sandy Ammophila (A. sabulosa, VAN DER LIND (Cf. idem: chapter 13.—Translator's Note.)) and the Hairy Ammophila (A. hirsuta, KIRB.) cram into each burrow a single but corpulent caterpillar, always of the Moth tribe and varying greatly in coloration, which denotes distinct species. The Silky Ammophila (A. holosericea, VAN DER LIND. (Cf. idem: chapter 14.—Translator's Note.)) has a better assorted diet. She requires for each banqueter three or four items, which include the Measuring-worms, or Loopers, and the caterpillars of ordinary Moths, all of which are equally appreciated. The Brown-winged Solenius (S. fascipennis, LEP.), who elects to dwell in the soft dead wood of old willow-trees, has a marked preference for Virgil's Bee, Eristalis tenax (Actually the Common Drone-fly and somewhat resembling a Bee in appearance. Cf. "The Hunting Wasps": chapter 14.—Translator's Note.), willingly adding, sometimes as a side-dish, sometimes as the principal game, Helophilus pendulus, whose costume is very different. On the faith of indistinguishable remains, we must no doubt enter a number of other Flies in her game-book. The Golden-mouthed Hornet (Crabro chrysostomus, LEP.) another burrower in old willow-trees, prefers the Syrphi, without distinction of species. (The Syrphi, like the Eristales, resemble Bees through having the abdomen transversely banded with yellow.—Translator's Note.) The Wandering Solenius (S. vagus, LEP. (For this Fly-hunting insect cf. "Bramble-bees and Others": chapters 1 and 3.—Translator's Note.)), an inmate of the dry bramble-stems and of the dwarf-elder, lays under contribution for her larder the genera Syritta, Sphaerophoria, Sarcophaga, Syrphus, Melanophora, Paragus and apparently many others. The species which recurs most frequently in my notes is Syritta pipiens.
Without pursuing this tedious list any farther, we plainly perceive the general result. Each huntress has her characteristic tastes, so much so that, when we know the bill of fare, we can tell the genus and very often the species of the guest, thus proving the proud truth of the maxim, "Tell me what you eat and I will tell you what you are."