Even more interesting than this roofing-work is the feeding of the grubs. One could never weary of the sight of the rough fighters turned into tender nurses. The barracks become a crêche. With what care those grubs are reared! If we watch one of the busy Wasps we shall see her, with her crop swollen with honey, halt in front of a cell. With a thoughtful air she bends [[150]]her head into the opening, and touches the grub with the tip of her antenna. The grub wakes and gapes at her, like a fledgling when the mother-bird returns to the nest with food.
For a moment the awakened larva swings its head to and fro: it is blind, and is trying to feel the food brought to it. The two mouths meet; a drop of syrup passes from the nurse’s mouth to the nurseling’s. That is enough for the moment: now for the next Wasp-baby. The nurse moves on, to continue her duties elsewhere.
Meanwhile the grub is licking the base of its own neck. For, while it is being fed, there appears a temporary swelling on its chest, which acts as a bib, and catches whatever trickles down from the mouth. After swallowing the chief part of the meal the grub gathers up the crumbs that have fallen on its bib. Then the swelling disappears; and the grub, withdrawing a little way into its cell, resumes its sweet slumbers.
When fed in my cage the Wasp-grubs have their heads up, and what falls from their mouths collects naturally on their bibs. When fed in the nest they have their heads down. But I have no doubt that even in this position the bib serves its purpose.
By slightly bending its head the grub can always deposit on the projecting bib a portion of the overflowing mouthful, which is sticky enough to remain there. [[151]]Moreover, it is quite possible that the nurse herself places a portion of her helping on this spot. Whether it be above or below the mouth, right way up or upside down, the bib fulfils its office because of the sticky nature of the food. It is a temporary saucer which shortens the work of serving out the rations, and enables the grub to feed in a more or less leisurely fashion and without too much gluttony.
In the open country, late in the year when fruit is scarce, the grubs are mostly fed upon minced Fly; but in my cages everything is refused but honey. Both nurses and nurselings seem to thrive on this diet, and if any intruder ventures too near to the combs he is doomed. Wasps, it appears, are far from hospitable. Even the Polistes, an insect who is absolutely like a Wasp in shape and colour, is at once recognised and mobbed if she approaches the honey the Wasps are sipping. Her appearance takes nobody in for a moment, and unless she hastily retires she will meet with a violent death. No, it is not a good thing to enter a Wasps’ nest, even when the stranger wears the same uniform, pursues the same industry, and is almost a member of the same corporation.
Again and again I have seen the savage reception given to strangers. If the stranger be of sufficient importance he is stabbed, and his body is dragged from the nest and [[152]]flung into the refuse-heap below. But the poisoned dagger seems to be reserved for great occasions. If I throw the grub of a Saw-fly among the Wasps they show great surprise at the black-and-green dragon; they snap at it boldly, and wound it, but without stinging it. They try to haul it away. The dragon resists, anchoring itself to the comb by its hooks, holding on now by its fore-legs and now by its hind-legs. At last the grub, however, weakened by its wounds, is torn from the comb and dragged bleeding to the refuse-pit. It has taken a couple of hours to dislodge it.
Supposing, on the other hand, I throw on to the combs a certain imposing grub that lives under the bark of cherry-trees, five or six Wasps will at once prick it with their stings. In a couple of minutes it is dead. But the huge dead body is much too heavy to be carried out of the nest. So the Wasps, finding they cannot move the grub, eat it where it lies, or at least reduce its weight till they can drag the remains outside the walls.