Wasps
These insects are too well known to every one to require any description of their form, colour, markings, or power of stinging. There are, however, several species of Wasps in Britain. Though they agree in so many respects that no one can fail to recognise them as Wasps; and though they are so like one another in form, in colours, and in markings that it is not very easy for any one but an entomologist to distinguish them, yet they differ in the places in which they make their nests, and in the means to be employed against them when they become troublesome in gardens. The True Wasps, belonging to the genus Vespa, are all social insects, like their kindred, the Honey Bees; but, unlike the latter, there is little difference between the sexes in outward appearance. The common Wasp is a good representative of the whole group, the sexes differing in little but size; and the other species being distinguished chiefly by the forms and sizes of the black markings that are scattered on the yellow ground-colour, and by the presence in some of rusty-brown spots on the sides of the body. The Wasps belong to a division of the Hymenoptera (which see), which have the fore wings folded lengthwise, like a fan, when at rest, and the bird wings hidden below them. This division, besides the true Wasps, includes a large number of insects, known as Solitary Wasps, that resemble them in general form, and to some extent also in colour: but anyone familiar with the appearance of the common Wasp will find no real difficulty in distinguishing the one from the other; while to state the characteristic distinctions would require more space than is here available, without affording any corresponding advantage. The Solitary Wasps are so named because they do not live in societies like the true Wasps; and each female among them forms the cells or chambers to be occupied by the larvae hatched from the eggs laid in them, and she stores the cells with the proper food. This frequently consists of larvae of small Moths, or of other insects; and the Wasps that capture these should be protected by gardeners as far as possible, as they assist in the destruction of noxious insects. The Solitary Wasps make the cells for the protection of their larvae in the most varied situations. Some females dig burrows in sandy soil, and at the end of each burrow form a cell, which is stocked with provisions, among which an egg is placed. Others tunnel in the pith of dead Rose-twigs, &c., while some take advantage of the burrows of other insects, or of any crevice, or even of empty snail-shells, in which to form the cells; and still others build mud cells, often of peculiar forms, against stones or on plants. It would be impossible to give a full account here of the exceedingly diverse habits observed among the Solitary Wasps. In regard to them it need only be added that none are injurious to gardens, while several are useful, as stated above.
To return to the Social or True Wasps, belonging to the genus Vespa. They are of doubtful reputation with gardeners, but are decidedly more hurtful than beneficial in gardens. It is true that they are voracious creatures, and feed largely on other insects, and that they destroy considerable numbers of noxious or troublesome species; but the benefits conferred by them in this way are more than counterbalanced by the injury they do to ripe fruits. They are very partial to apricots and plums; but, where these are not to be obtained, they attack gooseberries, leaving little but empty skins. They are extremely numerous in some seasons, while in others scarcely a Wasp can be seen. A brief account of their life-history will suggest suitable methods for lessening their numbers.
The Common Wasp (Vespa vulgaris)may be selected as representative of the genus in its life-history. Towards the close of autumn by far the greater number of the Wasps die; and only a few females survive the winter. The Wasps one sees in spring, exploring holes and crevices in the ground, in old walls, in heaps of rubbish, or in tree trunks, are females in search of secure retreats in which to form nests; and each one killed at this season prevents the formation of a nest during the summer. Those that find suitable localities enlarge them, if necessary, to the size required for the commencement of the nests. A very favourite locality is a mouse-hole. Each female works by herself for a time in forming her nest, the coverings and cells in which are made of a kind of paper. This substance, it is believed, is prepared form the fibres of wood rasped by the Wasps from the surface of naked trunks or of posts, rails, or other articles, moistened with a fluid form the mouths of the insects, and made into a paste. The Wasp fixes a short pillar of this to some firm body-e.g., the root of a plant, or a stone, in the roof of the hole-and then forms two or three cells, mouth downwards, on the free end of the pillar, and builds an umbrella-like roof above them. In each cell an egg is laid; and, after a short time, the larvae are hatched, and require to be tended and fed by the parent Wasp. The food given to the larvae while young is chiefly honey, taken from Bees, or from ripe fruits; but, when the larvae are older, they are fed on flies and other insects. When Wasps can gain access to grocers' and butchers' shops, they are apt to become trouble-some in their efforts to obtain sugar and animal food from the supplies in the shops, instead of from the usual sources. As the larvae grow, the cells have to be enlarged around them; and at last they become full-fed, spin over the opening of the cell, and pass into the state of pupae. The female Wasp continues to form new cells, and to feed the young brood; and, as soon as the perfect insects have emerged from the pupae, they assist her in her work. The Wasps that develop in early summer are incapable of laying eggs, and are called neuters; they are, in reality, females in which the reproductive organs remain undeveloped. As the number of cells is increased, the size of the hole must be enlarged, and the outer coverings of the nest removed and relaid, of a size to permit of the nest in its new dimensions being contained within them. As the number of Wasps is augmented from the young broods, the nest increases more and more rapidly in size, and combs are added, each new one being suspended from its predecessor by numerous supports of the papery material, strengthened by an extra allowance of the gluey secretion from the insects' mouths. Space is left between the combs to permit the Wasps to move about freely, and to gain easy access to every cell. Towards the end of summer, both males and females are developed, in addition to the workers or neuters, to secure the perpetuation of the species. When the winter is near, the Wasps have been observed to tear open the cells containing larvae, which they then destroy. The instinct to do so is a merciful one, as the larvae would otherwise perish of starvation, from the pain of which they are saved by this speedy mode of death. Besides V. vulgaris, certain other species of the genus make their nests in holes; but others suspend their nests from the branches of trees or bushes. Except in situation, the latter nests agree with those formed in holes, the outer covering being made sufficiently strong to prevent injury from the weather; these nests are entered by a small hole below, or on one side near the bottom. The Hornet (V. Crabro) differs from its congeners in its larger size. It is not scarce in the South of England, where it nests in hollow trees or in outhouses. The material employed by Hornets in making the paper for their nest is usually rotten wood. These insects sting much more severely than Wasps; but they feed almost wholly on other insects, including Wasps, and must be regarded as friends in the garden.
Remedies. In districts where Wasps are very numerous, it is often necessary to destroy them and their nests, in order to protect the fruit, and to prevent annoyance from their entering houses, and using their stings. Prevention is best secured by encouraging the capture of the females in spring, as this prevents them from commencing the nests. The numbers may also be lessened either by capturing the insects, or by destroying the nests. Wasps may be caught in summer and autumn in various simple traps-e.g., a bottle containing a little sweet fluid of any sort suspended in a tree. A good trap is easily prepared by placing a bell glass on three supports, so as to leave space for insects to fly or crawl in below to the bait (sugar, treacle, or other sweet stuff), placed in a plate under the bell glass. The latter should open at the top by a hole, and above it should be placed another glass, closed at the top. The insects, on rising from the bait, fly upwards, pass through the hole in the lower glass, and are trapped in the space between it and the upper one. The glass "fly-catchers," now coming into use, effect the capture of Wasps in a similar way, and deserve a trial by any one troubled with an abundance of the insects. The situations of the nests determine the most likely methods to insure their destruction. The Wasps do not work at night, hence that time should be chosen for operations against them. Nests in holes may be destroyed by means of squibs of mealed gunpowder and sulphur. One of these should be pushed through a piece of turf about a foot square, and two or three inches thick; the squib should be lighted, and put into the Wasps' burrow, and the turf closely pressed down to keep in the smoke. Wet mud plastered round the turf helps in this object; and some of the mud should be placed over the hole when the squib is driven out by the final explosion. A more difficult method is to flood the nest with hot water. Tree Wasps' nests can best be destroyed by placing a pail of water underneath at night, and cutting the support of the nest, so as to allow the nest and its occupants to fall into the water. The pail should have a lid, in case any of the Wasps should climb out of the water. Such nests may also be smoked with sulphur, but with less certain results.
In the article on the Honey Bee (Apis mellifica), the promise was made that the habits of that insect should be treated of in connection with those of Wasps, with which the former insect agrees in many particulars. Some of the leading features of agreement and of difference between them are, therefore, here briefly indicated.
Like the social Wasps, the honey bees live in large societies, including workers (or neuters), females (or queens), and males (or drones), and form their nests in holes when in the wild state. Bees in domestication live in hives; but not infrequently a swarm, on leaving the parent hive, will select a hole for themselves, from which it is often very difficult to dislodge them. But though Bees agree with Wasps in these respects, they differ from them in many important particulars, and to these points of difference attention must now be given.
Bees from new nests in a different way from Wasps. The females, or queen bees, do not themselves work at the nests; nor do they rear the young grubs or feed them, as is done by the female Wasps in spring. The only duty of the queen bees is to lay eggs, which are at once taken care of by the workers; and the latter alone nurse the grubs, and look after the pupae. The queens leave the nests to pair; and after they have paired they return very soon, and never again leave the hives, except in swarming, when one queen goes with each new colony. At all other times they remain inside, surrounded by a multitude of workers, which feed their queen, and follow her as she deposits her eggs in the cells prepared for them. Each new nest of honey bees is thus not the work of a single female, but is formed by a colony or swarm from some older nest, the bees in which have become too numerous to remain at home with advantage to the commonwealth. Each swarm consists of a queen and a number of workers. Among Wasps there is, comparatively, little difference between workers, females, or males; but among honey bees the differences are evident. Fig. 215 shows that they differ in size and form of body; and also that the eyes of the male are so large as to meet on the top of the head; while in the females and neuters the eyes are entirely lateral. The males, or drones, take no part in the work of the hive. They are produced from eggs laid usually in April or May, and assume their perfect condition in summer. They fly during the warmest part of the day, and pair with the newly-emerged queens during flight. If the impregnation of a queen is retarded till twenty-eight days after hatching, she lays only male eggs. In hives where the queen is laying eggs from which workers can be reared (i.e., if impregnation has not been long delayed after she reached maturity), it has been observed that the workers, towards the beginning of autumn, attack the drones, and kill them by stinging them. Where the queen is capable of laying only male eggs, and also when the queen has died, or has been removed from the hive, the males are not killed till a fertile queen has been secured. There is only one queen bee in each hive; but if she is lost, the workers proceed to rear others from worker-larvae, by enlarging their cells and supplying them with abundance of food. This treatment causes the earlier stages to be passed through in a shorter time, and also produces a marked result in modifying the bodily structure-the bees produced being true females, with all the physical peculiarities that distinguish the latter from the workers. When it is necessary to replace a queen, there are usually from twelve to twenty larvae reared for the purpose. As soon as the first queen that reaches maturity is able, she goes round the cells containing the others, still in the state of pupae, and gnaws a hole in each cell. If the cell contains a queen ready to emerge, the latter is stung by her older rival. The workers pull the pupae or dead bodies of the queens from the cells, and remove them. Should two queens emerge at the same time, it has been observed that one kills the other. So, also, when a stranger queen is introduced into a nest, she and the rightful queen fight till one is killed. At the periods of swarming, the workers prevent the slaughter of as many young queens as are required for the nest and the swarms. The old queen leads off the first swarm; and the young females that are to go with new swarms are not permitted to emerge from their cells till the swarms are ready to depart. Thus fatal contests are prevented among them.
The workers differ from the queens as follows: They are smaller; the jaws, or mandibles, are more prominent; the maxillae and tongue are longer, and the upper lip and antennae are black (in the queens the upper lip is fulvous, and the antennae are pitchy-brown); the legs are black, with the tarsi brownish; the basal joints of the tarsi, and the tibiae of the hinder legs, are broader, and hollowed externally, and bear stiff hairs on the sides and across them, so placed as to form a receptacle in which to carry the pollen, or "bee-bread," collected from flowers for the nourishment of the bees and of the larvae; the abdomen is broader and less pointed, and the three middle segments bear a small wax-pocket on each side near the base. These differences are very considerable; yet the facts that the larvae of workers can be made by special treatment to produce queens, and that the workers possess (functionless) representatives of ovaries, show that they are indeed females in which the reproductive organs have remained undeveloped, and which are fitted to perform special duties for the good of the community. The workers do all the work of the hive: they build the cells, collect the honey, pollen, and a resinous substance known as "propolis," and feed and attend to the young. These operations are so varied that they are divided between two classes of workers, of which one prepares the wax, and the other attends more especially to building it into cells, collecting the food, and rearing the young. The makers of wax eat some sugar or honey; and a number of them cling together, in a cluster of festoons, for about twenty-four hours, without active movement. During this time, the wax is formed in thin plates, one in each of the little pockets mentioned above as occurring on the three middle segments of the abdomen. When the wax is formed, the bee detaches the plates from the pockets, and chews them up, mixed with a liquid from the mouth, into a riband, which is deposited on the place where it is to be made into cells. After the wax-makers have deposited the materials, the other class of workers build it up into the cell walls, making the cells larger or smaller, as required for the females, males, and workers. The edges of the cells are finished with a kind of adhesive varnish, which melts less easily than wax, and is redder in colour. This is the "propolis," which the bees collect from the bud-scales of Horse Chestnuts, Poplars, and other trees possessed of sticky buds. Attention has frequently been called by zoologists and mathematicians to the regularity of form and of size in the cells, and also to the fact that their form secures the greatest possible inclosed space with the smallest possible expenditure of wax.
Many of the cells are occupied by larvae or pupae; but others are employed as storehouses for the honey, and often the cells from which young bees have emerged are cleared out and filled with honey. The visits made by bees to flowers, in the course of which they are of so great use in effecting pollination in many plants, have as their object the collection of nectar and of pollen. (see Nectar, Nectary, Orchid Fertilisation, and Pollination). The bees swallow the nectar, and continue their visits to flowers till the stomach, or honey-bag, is filled with the sweet fluid. They then collect the pollen, forming little masses of the grains brushed off their bodies; they place them upon the hairy, flattened portions of the hind legs, and they thus form a load of food to be carried back to the hive. In the stomach the nectar undergoes a change by which it is converted into honey, and this is either given at once by the collectors to those bees that have been at work in the hive, as food, or is poured into the cells. Those which contain honey that is soon to be used are not closed; but such as are reserved for food during winter are covered with wax. The pollen is either eaten by the bees themselves, or is given to those that have been at work in the nest, or to the larvae, or it is stored away in cells for future use. On these stores the bees subsist during winter; hence the nests are not broken up on the approach of cold weather: nor do the bees resemble Wasps in destroying their larvae in autumn, as they can provide them with food. When the honey is taken from hive bees, it is necessary to supply them with sugar and water, or with other sugary substances, from which they can prepare honey. It may be mentioned, in conclusion, that there are several kinds of bees in domestication, of which A. mellifica is the commonest, and has been specially kept in view above; the other species differ only from it in minor details.