Brood (entomology)

“ The brood consists of seven or eight eggs of a green colour, sprinkled with brown spots. In three weeks the young are hatched, and are fed by both parents on a great variety of insects, earthworms and snails, the greatest caution being employed to avoid discovery of the nest; and so attached are the parents to their offspring, that we have known a female continue to brood after having received a shot in her body. ”

“ Where fresh sets are found late in the year, the first have generally been destroyed, and a second brood is uncommon, though the contrary holds true during vole- or lemming-plagues, when food is unusually abundant; at such times, moreover, the number of eggs is abnormally large for the species. ”

“ I have never been able to conceive why a bird which produces more than one brood in a season, should abandon its first nest to construct a new one, as is the case with the present species; while other birds, such as the Ospreys, and various species of Swallows, rear many broods in the first nest which they have made, and to which they return, after their long annual migrations, to repair it, and render it fit for the habitation of the young brood. ”

“ It is evident that a pair of phœbes must materially reduce the number of insects near a garden or field, as the birds often, if not always, raise two broods a year, and each brood numbers from four to six young. ”

“ It is stated that there is only one brood, [16] but I feel fairly sure that a second brood is sometimes produced, and that the females with a yellow ground and diminished irroration of the veins, not very uncommon in the Italian Alps in July to August, are generally representatives of it. Such insects would of course be classed with bryoniae in collections. ”

“ They remain until October, but, I am inclined to believe, rear only a single brood in a season. The nest is fixed in the fork of a small twig bending over the water, and is constructed of slender grasses, soft mosses, and fine fibrous roots. The number of eggs is from four to six. I could never ascertain whether the male assists in incubation, as the difference of plumage in the sexes is not perceptible when the bird is at large, and indeed can hardly be traced when one has procured the male and the female for comparison. It cannot be called a plentiful species. ”

“ In the house it must be first fed on ants’ eggs, flies, and meal-worms. It will afterwards eat nuts and hemp-seed, like the other tits, but it seems to require insects occasionally.
Breeding.—The nest is formed like that of the cole tit, and placed in the hole of a tree, amongst some stones, or in large forsaken nests. The brood consists of from six to ten snow-white eggs, spotted with bright red. The young must be reared on meal-worms cut small and ants’ eggs. ”

“ Foul brood is the rotting of brood in a hive; the caps of the sealed brood appear indented and shriveled and the larvae and young bees in unsealed cells become putrid, emitting a disgusting stench or smell. When the disease has a firm hold, even though it may be possible to cure it, I would advise the total destruction by fire of the bees, combs, frames and hives, with everything which might harbor the disease. ”

“ She does not wait, however, for one brood to be hatched before laying the eggs of another, but, as soon as food enough has been collected, she lays the eggs for a second. The eggs are laid, in contact with each other, in one cavity of the mass of pollen, with a part of which they are slightly covered. They are very soon developed; in fact, the lines are nowhere distinctly drawn between the egg and the larva, the larva and pupa, and again between the latter and the imago; a perfect series, showing this gradual transformation of the young to the imago can be found in almost every nest. ”

“ At this moment the brood issue from the ground, leaving innumerable exit holes, and swarm over trees and shrubs, filling the air with their strident calls, and laying their eggs in slits which they cut in the trees. The larvae, when hatched, fall to the ground, and quickly burrow out of sight, each "forming for itself a little subterranean chamber over some rootlet, where it remains through winter and summer, buried from sun, light, and air, and protected in a manner from cold and frost.... ”

“ The life of a winged insect, such as a butterfly, fly, or bee, may be divided into four stages: the embryo, or egg state, the larva, pupa, and imago,—the term metamorphosis being applied to the changes after birth, or post-embryonic stages of life. The transformations of the more specialized orders of insects involve wonderful changes of form, which are only paralleled in other types of animals by the metamorphoses of the echinoderms, of certain worms, and of the Crustacea, as well as by those of the frog. ”

“ The first brood consists wholly of workers, and numbers between twenty-five and forty in some species, but is smaller in others. The mother ant seeks food for herself and her young till the initial brood are matured, when they take up the burden of life, supply the rapidly increasing family with food, as well as the mother ant, enlarge the quarters, share in the necessary duties, and, in short, become the real workers of the nest before they are scarcely out of the shell. ”

“ The migratory species in the majority of instances probably confine themselves to one brood, while nearly all the Finches regularly have a second nest. It is not, I think, difficult to see why they respectively lay their five and ten eggs a season, and neither more nor less. These birds, resident and migratory alike, feed their young on various forms of insect-life—flies, grubs, aphides, the smaller kinds of caterpillars, and the ova of these insects. ”

“ When there are two broods in a season, the second brood unites with the first, and, if unmolested, they keep together until the spring, under the guidance of the parents. In the mating-season they usually separate into pairs, though occasionally a male will associate with more than a single female, in which case their joint product is united in the same nest. In the spring of 1850 I found one of the nests which contained no less than thirty-two eggs. ”

“ See “Zeitschrift f. wiss. Zool.” vol. xxii. 1872.
41 See my essay “Über den Einfluss der Isolirung auf die Artbildung.” Leipzig, 1872.
42 [In the case of monogoneutic species which, by artificial ‘forcing,’ have been made to give two generations in the year, it has generally been found that the reproductive system has been imperfectly developed in the second brood. A minute anatomical investigation of the sexual organs in the two broods of seasonally dimorphic insects would be of great interest, and might lead to important results. R.M.]
43 “Grundzüge der Zoologie.” ”

“ Such dead brood is frequently mistaken, by persons unfamiliar with the brood diseases, for one or the other of them. Careful examination will soon determine whether dead brood is the result of disease or merely some outside change. If brood dies from chilling or some other such cause, it is usually soon carried out by the workers, and the trouble disappears. No treatment is necessary. Brood which dies from external causes often produces a strong odour in the colony, but wholly unlike that of American foul-brood—merely that of decaying matter. ”

“ The reproduction of all insects takes place by ova, and they are diæceous—that is, have two distinct sexes. In some few instances, as that of Aphides, or plant-lice, we have the peculiar phenomenon of parthenogenesis, the process of reproduction being performed by imperfect wingless females. These bring forth living young ones, which begin to feed the moment they are born, and constitute a viviparous brood; in other cases females lay eggs, and the process proceeds in the ordinary way, and nearly all the year round. ”

“ Internal parasites and "saprophytes," that is, beings which live on dead and decayed organic matter, on the other hand, live surrounded by a supply of dissolved food; and rarely do we find larger cells, richer in reserves, than in the parasitic Sporozoa, which owe their name to the importance of brood-formation in their life-history. In Radiolaria (p. 75 f.) a central capsule separates off an inner layer of protoplasm; the outer layer is the one in which digestion is performed, while the inner layer stores up reserves; and here brood-formation appears to be the rule. ”

“ She cannot bear thirst and it makes her do strange things. There may be new broods of young five or six times a year, and if only three or four of each brood live there will be a good many by the year's end. ”

“ Many female moths may be induced to lay their eggs in captivity, especially if put in a box with some of the food-plant of the larva. It is extremely instructive and interesting to rear an insect from the egg. When the young larvæ first emerge they must be kept in a tumbler with a piece of glass put over the top, as they might escape through the ventilators of the cages, but they ought to be transferred immediately they are large enough. ”

“ The illustration (fig. 27) shows a portion of comb affected with foul brood in its worst form. The sealed cells are dark-coloured and sunken, pierced with irregular holes, and the larvae in all stages from the crescent-shaped healthy condition to that in which the dead larvae are seen lying at the bottom of the cells, flaccid and shapeless. ”

“ Early in the fall the various broods begin again to associate together, and at the approach of winter it is not uncommon to see them in flocks of several hundred individuals.
The young broods, when come upon suddenly and taken by surprise, instantly scatter and squat close to the ground, so that, without a dog, it is impossible to find them. ”

“ The resident small birds, however—Finches, Buntings, &c.—are not hampered by the approach of the period of migration, and they indulge in a second brood. It is necessary for them to produce eight or ten of their kind in a season to aid in killing off from the cultivated lands the vast swarms of insects to which the summer has given birth, and which the efforts of the parents when feeding have proved utterly inadequate to cope with. ”

“ Its nest is constructed in crevices in the bark of trees, &c., the insect very frequently selecting the spaces between the boards of outhouses, where the loud buzzing noise made by the perfect bees when emerging from their retreat at once arrests our attention. These nests consist of about ten oval cells, formed of clay, and neatly smoothed within. They are all constructed by a single female, which also provisions them with honey and pollen, depositing an egg in each. The larva, after consuming the food, changes into a pupa, from which the perfect insect emerges about January. ”

“ All these are necessary cautions, and there are still some others not to be neglected; for example brood-mares ought never to be docked, because, being unable to defend themselves from the flies, they are continually tormented, and the constant agitations which the stings of these insects occasion diminish the quantity of their milk, which has great influence on the temperament and size of the foal, which in every respect will be more vigorous as the mother is more capable of nursing it. ”

“ As a rule, I believe indeed, this advantage of a more numerous brood will not by any means outweigh that of a more perfect brood, but it will do so in those cases in which the chief difficulty of the young animals consists in finding a suitable place for their development, and in which, therefore, it is of importance to disperse the greatest possible number of germs, as in many parasites. ”

“ How can the poor blow-fly, when it leaves its eggs on our food, be certain that it is appointing a suitable place for the birth-spot of its progeny? Why does it not select the green surface of the leaf, or the warm corner of the window, or the bare earth, for this purpose? We might say, perhaps, in this instance, that the insect is only choosing the place where it obtains its own food. But what shall we say when we find insects, such as the butterfly, depositing their eggs upon plants which they never frequent at any other time, and from which they never obtained a particle of food themselves? ”

“ Unlike those of the Crustacea, the limbs of insects are not primitively biramose, but single, the three-lobed first maxillæ, and secondarily bilobed second maxillæ being the result of adaptation. Embryology on the whole proves the truth of this assumption; the maxillæ of both pairs are at first single buds, afterwards becoming lobed. All the appendages of the body, including the ovipositor or sting, are modified limbs, as shown by their embryological development. ”

“ It is probable that the female insect does not leave her case, communication with the male being no doubt effected through one of the orifices, and the eggs afterwards deposited inside. On one occasion I found a case full of eggs, containing the shrivelled body of the female and her old pupa shell, which would seem to confirm the above opinion. ”

“ The amount of brood is at first small, and as the new workers emerge they assist in the brood rearing so that the extent of « 27 » the brood can be gradually increased until it reaches its maximum about the beginning of the summer. ”

“ These later stages, comprising the greater part of the larval history, are adapted for an inquiline or a parasitic life, where shelter is assured and food abundant, while the short-lived, active condition enables the newly-hatched insect to make its way to the spot favourable for its future development, clinging, for example, in the case of an oil-beetle’s larva, to the hairs of a bee as she flies towards her nest. ”