Philip Woolf

“ Reproductive organs that do not produce are of no use to their possessors; and, as this slightly less developed but useless reproductive system would require more attention and more food from the fertile nurse than would those larvæ in which it was a mere rudiment, natural selection, by working on the instinct of the nurses, would modify, alter, or even suppress what was of no use. ”

“ Supposing, then, that originally the females undertook most of the work now done by the neuters; supposing, also, that at the beginning of spring there are only a few females, or even one female, to commence the work of building the nest and feeding the future progeny. With many duties to perform, it is not unwarranted to conclude that some duties may not be completely performed. The immediate success of the colony depends, not so much on the number of males or of females, as on a body of efficient assistants. ”

“ But—and here is the great difficulty—how can the changed male have given his lost organs to his sex, and the female have transmitted her original but now modified peculiarities to the workers; especially as neuters do not propagate, and hence can not transmit their characters to progeny? Another law solves a portion of the difficulty: peculiarities acquired at any period of life are apt to appear in the same sex at the same time of life. ”

“ Carpenter is now a commonplace of science: "There is a certain degree of antagonism between the nutritive and reproductive functions, the one being executed at the expense of the other. The reproductive apparatus derives the materials of its operations through the nutritive system, and is entirely dependent on it for the continuance of its functions. ”

“ The growing body must have enough material out of which to elaborate tissue, or the tissue, muscle, nerve, bone, can not develop. Now let it be supposed there are two larvæ or grubs of the bee, which under similar conditions will reach similar degrees of development; further suppose that one larva, which may be called A, receives an over-abundance of food, while the other larva, which may be called B, receives a quantity of food just sufficient for its more important wants, what will happen? ”

“ In other words, to render this conclusion plain to the general reader, we believe that if the neuter-worker of the white ant, for example, were to progress in development, it would turn into the fertile female; if the neuter soldier of the white ant were to continue on the line of development, it would become a fertile male. ”

“ Thus with the bee, the cell in which the queen is hatched is larger, differently formed, and in weight said to be equivalent to one hundred ordinary cells; the cells from which emerge the males are also larger than the cells of neuters. Now, the extra labor necessary to produce these cells in founding a new colony, the extra labor in attending to the inmates, and the non-necessity of having males or females at this early stage of colonial existence, are other reasons why the first-laid eggs produce only neuters. ”

“ Several butterflies have three kinds of females, or are trimorphic. Hence the mere differences between neuter and perfect insects are nothing unusual, considered as differences. Were the workers fertile and thus able to propagate their peculiarities, the difficulties would vanish; but the problem why a fertile female should give birth to two or three distinct forms is still shrouded by mysteries, accept what explanation we may. ”

“ In a given neighborhood those insects which produce a corps of assistants soonest, and with least expenditure of labor, will stand a better chance of obtaining food—of surviving—than those insects which give the same amount of attention to each larva, rearing them all into perfect insects—a benefit also accruing to the earlier hatched larvæ themselves, as they sooner reach maturity, and can thus obtain an abundance of food without rivalry. These earlier produced neuters have their reproductive systems only slightly less developed than egg-bearing insects ”

“ If the males no longer use their heads and jaws to protect the community, these parts would decrease in size; if the females no longer assist in building, if their entire duty is to lay eggs, their wings, legs, jaws, etc., will decrease; the surplus of force thus entailed being added to the reproductive system. Thus, then, there would have been produced the four castes found among the termites; the soldier representing the typical male of the species, the workers the typical females minus the perfected reproductive organs. ”

“ At such time when each hive only contained one reigning queen, this female had to assume the reproductive functions of her twenty thousand sterile sisters, and it is not strange that she has no time to build or to feed the young. Under no other conditions could she lay her two thousand to three thousand eggs a day. The case of the termites or so-called white ants is more striking, the female laying eighty thousand eggs in the course of a day, or very nearly one egg a second continuously. ”

“ By natural selection modifying the instincts of the nurse. What at first arose through the incapability of one or several insects taking care of many insects, became through the action of natural selection, by the survival of those insects which produced a given result with least labor to themselves, an established instinct. Further questions may be now asked: Why is it that any other insects besides neuters have been produced? ”

“ The neuters continuing to increase as we know they have increased, and the true males and females decreasing in number as we know they have decreased, a state of affairs is reached in which it is essential to the welfare of the colony that the male should confine himself to fertilizing the female, the female principally confine herself to laying eggs. ”

“ This does not give support to the theory that the worker and soldier are immature male and female; that they are the perpetual babies, while the perfect insects are adults—since we believe that in their way the neuters are as adult as their parents. ”

“ With bees, then, we see that the neuter is only a female with the reproductive organs partially developed, a conclusion further enforced by the fact that the neuter sometimes even lays eggs which develop into the drone or male bee. ”

“ Applying this theory to facts, we can see why with the increase of neuters the duties of the queen-bee have grown less and less until they consist of nothing but ovulation. The queen-bee is a queen only in name, receiving just such extra care that her time may be entirely devoted to propagating the species. ”

“ If during the breeding season a strange male attempts to enter the burrow, he is attacked; the female does not remain passive, but closes the mouth of the burrow and encourages her mate by continually pushing him from behind. ”

“ The suggestion of Professor Wyman, that the difference in development is due to the difference in the time the eggs are laid after fertilization, seems to be opposed to facts; especially to the experiment of Kleine, who reared worker-larvæ into queens by feeding them on royal food. The other conclusion is, that the neuters represent the type from which the true males and females have diverged; that in those cases where food is powerless, the neuter retains its immutability for the reason that its development is arrested at a certain stage ”

“ This conclusion is no mere theory, for among the higher animals, and even with man himself, insufficient nourishment first produces its effects on the reproductive system. Loss of blood induces abortion; badly prepared or insufficient food decreases or entirely checks the production of offspring. ”

“ It is said that, since they do not propagate their kind, no spontaneous variations can be produced for natural selection to work on, and hence that there is no other explanation of their existence than that they are specially created—that is, created in opposition to law. ”

“ Both workers and soldiers are blind, but whereas the workers have a somewhat circular head and small jaws, the soldiers have a comparatively enormous head, and strong resisting mandibles. In what manner then, or through what cause, could the head of this soldier termite differ so greatly from either that of the perfect male or perfect female? ”

“ That males are not always passive, the work just quoted abundantly proves. Now when neuters are produced from males their duties differ from the neuters produced from females, and, as we have supposed that the duties now performed by sterile females were once performed by fertile females, so we may now conclude that the duties performed by sterile males were once performed by the perfect males. ”

“ To simplify the initial inquiry, we will suppose that workers differ from females only in that they are not fertile, the secondary differences being reserved for discussion toward the end of this paper.
That a creature may develop, it is essential that it be supplied with a sufficiency of food. Even with human beings food is all-important ”