Reaumur, from whom (see the sixth Memoir of his last volume) most of these observations are taken, put the nests of wasps under glass hives, and succeeded so effectually in reconciling these little restless creatures to them, that they carried on their various works under his eye: and if you feel disposed to follow his example, I have no doubt you will throw light upon many parts of their history, concerning which we are now in darkness.
Having given you some idea, imperfect indeed from the want of materials, of the societies of wasps, I must next draw up for you the best account I can of those of the humble-bees[119]. These form a kind of intermediate link between the wasps and the hive-bees, collecting honey indeed and making wax, but constructing their combs and cells without the geometric precision of the latter, and of a more rude and rustic kind of architecture; and distinguished from both, though they approach nearer to the bees, by the extreme hairiness of their bodies.
The population of a humble-bees nest may be divided into four orders of individuals: the large females; the small females; the males; and the workers.
The large females, like the female wasps, are the original founders of their republics. They are often so large, that by the side of the small ones or the workers, which in every other respect they exactly resemble, they look like giants opposed to pygmies. They are excluded from the pupa in the autumn; and pair in that season, with males produced from the eggs of the small females. They pass the winter under ground, and, as appears from an observation of M. P. Huber, in a particular apartment, separate from the nest, and rendered warm by a carpeting of moss and grass, but without any supply of food. Early in the spring, (for they make their first appearance as soon as the catkins of the sallows and willows are in flower,) like the female wasps, they lay the foundations of a new colony without the assistance of any neuters, which all perish before the winter. In some instances however, if a conjecture of M. de la Billardière be correct, these creatures have an assistant assigned to them. He says, at this season (the approach of winter) he found in the nest of Bombus Sylvarum some old females and workers, whose wings were fastened together to retain them in the nest by hindering them from flying; these wings in each individual were fastened together at the extremity, by means of some very brown wax applied above and below[120]. This he conceives to be a precaution taken by the other bees to oblige these individuals to remain in the nest and take care of the brood that was next year to renew the population of the colony. I feel, however, great hesitation in admitting this conjecture, founded upon an insulated and perhaps an accidental fact. For, in the first place, the young females that come forth in the autumn, and not the old ones, are the founders of new colonies; and their instinct directs them to fulfill the great laws of their nature without such compulsion; and in the next, the workers are never known to survive the cold of winter.
The employment of a large female, besides the care of the young brood before described, and the collecting of honey and pollen, is principally the construction of the cells in which her eggs are to be laid; which M. P. Huber seems to think, though they often assist in it, the workers are not able to complete by themselves. So rapid is the female in this work, that to make a cell, fill it with pollen, commit one or two eggs to it, and cover them in, requires only the short space of half an hour. Her family at first consists only of workers, which are necessary to assist her in her labours; these appear in May and June: but the males and females are later, and sometimes are not produced before August and September[121]. As in the case of the hive-bee, the food of these several individuals differs; for the grubs that will turn to workers are fed with honey and pollen mixed, while those that are destined to be males and females are supplied with pure honey.
The instinct of these larger females does not develop itself all at once: for it is a remarkable fact, that when they are first hatched in the autumn, not being in a condition to become mothers, they are no object of jealousy to the small queens, (as we shall soon see they are when engaged in oviposition,) and are employed in the ordinary labours of the parent nest—that is, they collect honey and pollen, and make wax; but they do not construct cells. The building instinct seems as it were in suspense, and does not manifest itself till the spring; when the maternal sentiment impels them at the same time to lay eggs and to construct the cells in which they are to be deposited.
I have told you above, that amongst the wasps a small kind of female has been discovered: this is the case also amongst the humble-bees, in whose societies they are more readily detected: not indeed by any observable difference between them and the workers, but chiefly by the diversity of their instincts:—from the other females they are distinguished solely by their diminutive size. Like those of the wasps and hive-bees, these minor queens produce only male eggs, which come out in time to fertilize the young females that found the vernal colonies. M. P. Huber suspects that, as in the case of the female bee, it is a different kind of food that develops their ovaries, and so distinguishes them from the workers. They are generally attended by a small number of males, who form their court.
M. Huber, watching at midnight the proceedings of a nest which he kept under a glass, observed the inhabitants to be in a state of great agitation: many of these bees were engaged in making a cell; the queen-mother of the colony, as she may be called, who is always extremely jealous of her pygmy rivals, came and drove them away from the cell;—she in her turn was driven away by the others, which pursued her, beating their wings with the utmost fury, to the bottom of the nest. The cell was then constructed, and two of them at the same time oviposited in it. The queen returned to the charge, exhibiting similar signs of anger; and, chasing them away again, put her head into the cell, when seizing the eggs that had been laid, she was observed to eat them with great avidity. The same scene was again renewed, with the same issue. After this, one of the small females returned and covered the empty cells with wax. When the mother-queen was removed, several of the small females contended for the cell with indescribable rage, all endeavouring to lay their eggs in it at the same time. These small females perish in the autumn.
The males are usually smaller than the large females, and larger than the small ones and workers. They may be known by their longer, more filiform, and slenderer antennæ; by the different shape and by the beard of their mandibles. Their posterior tibiæ also want the corbicula and pecten that distinguish the individuals of the other sex, and their posterior plantæ have no auricle. We learn from Reaumur that the male humble-bees are not an idle race, but work in concert with the rest to repair any damage or derangement that may befall the common habitation.