The Courtship of Animals

by W. P. Pycraft

These most patient observers seem to have been convinced that whenever Spiders possess vividly coloured areas on their bodies they are not only conscious of this fact, but desire to make the most of such splendour during the period of love-making. Thus they interpret the behaviour of a curiously ant-like Spider—Synageles picata—which has the first pair of legs especially thickened, flattened on the anterior surface, and of a highly iridescent steel-blue colour. As he approaches the female he pauses “every few moments to rock from side to side, and to bend his brilliant legs so that she may look full at them; ... he could not have chosen a better position than the one he took to make a display.” And similarly they interpret the movements of another species—Dendryphantes capitatus—which has a bronze-brown face, rendered conspicuous by snow-white bands. The attitude he assumes when sexually excited is one which seems, to them at any rate, to serve admirably to expose this feature to the watchful female. But he has other charms, and his “antics are repeated for a very long time, often for hours; when at last, the female, either won by his beauty or worn out by his persistence, accepts his addresses.” Habrocestum splendens—unhappily these creatures have no names in common speech—possesses an abdomen of a magnificent purplish red, and the attitude which he assumes at courtship they regard as one designed to display this to the full. Another case of quite remarkable interest is that of Astia vittata, because the males appear to be dimorphic. That is to say, they appear under two quite distinct forms, the one red, like the female; and the other black, with three tufts of hair just behind the head. The attitudes and the movements of courtship, it is significant to remark, are entirely different in the two varieties: the black form, assumed to be the later development, “is much the more lively of the two, and whenever the varieties were seen to compete for a female, the black one was successful.”

Professor Poulton, commenting on this particular case, contends that “it must be admitted that these facts afford the strongest support to the theory of Sexual Selection.” But do they? A further examination of the facts will probably show that the red “form” is but an immature example, and this being so, the difference in performance and the invariable success of Othello is at once accounted for. The fact that the “two forms pass into each other” and that the “tufts only occur in the fully developed niger form” is an additional reason for regarding the red form as immature.

Professor Poulton remarks: “When the males possess any special adornment they make a point of displaying them as fully as possible.” If this be so it seems to be a very foolhardy proceeding, akin to holding the proverbial “red rag” to a bull: for it is well known that the male Spider seeking a mate carries his life in his hands, at any rate in the case of many species. Mr. and Mrs. Peckham observed several instances of this remarkable sequel to Love’s embraces. In describing the female of Phidippus morsitans they remark that she was “a savage monster. The two males we provided for her had offered her only the merest civilities, when she leaped upon them and killed them.” The first pair of legs in the males of this species possess “special adornments” in the shape of long white hairs, and it was “while one of the males was waving these handsome legs over his head that he was seized by his mate and devoured.” Again, in the case of a male of Phidippus rufus, the display of his “ornaments” was his undoing, for he was “caught and eaten when he insisted upon showing off his fine points too persistently.” Thus the females seem to “select” the more resplendent males as much for eating as for mating! The ogre-like habits of the females in this regard, indeed, are almost without parallel in the animal kingdom.

Anyone who cares to take the trouble to watch the web of the large Garden Spider (Epeira diademata) may witness one of these connubial tragedies. In this species, the males are conspicuously smaller than the females, and it is possible that this disparity has been brought about by Sexual Selection, the largest and least active males having been exterminated. In some species the discrepancy in size is most striking, as for example in Nephila chrysogaster, the female of which measures two inches in length, the male not more than one-tenth of an inch, and less than one one-thousand-three-hundredth part of her weight.

The males, apparently, fully realize the perils which their amours may lead them into. They haunt the borders of the webs of unmated females, but exhibit a hesitating, irresolute manner. For hours they will linger near her, feeling the silken carpet cautiously with their legs, and apparently trying to ascertain the nature of the welcome likely to be extended to them. The odds are against them: for even if allowed to mate, unless they are extraordinarily agile in slipping away the moment they have attained their object, the chances are they will be slain and eaten!

Among some species, however, matters are otherwise: for the males of the genus Linyphia, for example, are generally to be found living peacefully with their consorts.

More rarely the male weaves a small nuptial tent, into which he partly leads and partly drives the female: though the “driving” would appear to be merely for form’s sake! The habits of the Cellar Spider (Tegenaria parietina), a long-legged species fairly common in the South of England, affords a yet further interesting and instructive contrast with the foregoing accounts. The pairing habits of this species have been studied by many observers, but perhaps the best account is that of Mr. F. M. Campbell. He found, to begin with, that in this species the tender ties of mating are at any rate rarely violated by the horrible aftermath of cannibalism so common a feature with so many other Spiders.

One or two illustrations from Mr. Campbell’s work must suffice. On one occasion he placed together a male and a female. For four days they took no notice of one another; then the female cast what proved to be her last skin, and within three hours after, the male began to show signs of interest in her presence—which is a fact of some significance, for not till then had she attained maturity. “After a few convulsive twitchings of the legs, the male pressed forwards, moving his palpi”—the leg like “feelers” on each side of the head which form the genital organs (page 241)—“up and down, when, as they touched the palpi of the female, the pair played with these organs like two friendly bees with their antennæ. After a few minutes the female raised herself, leaning a little on her left side, and the male crept forward until his head was under the breast of his mate, while his first pair of legs were resting upon hers. He now advanced his right palpus, leaning a little to the left and using the left palpus as part of his support. The right palpus was slightly twisted so as to bring the surface (containing the fertilizing germs) opposite the sexual organs of the female.... He now rapidly raised his palpus up and down for four or more seconds, and with such energy as to compel her to assume a vertical position. He then retired and again approached her, repeating the movements ... occasionally pausing before he withdrew his palpus.... At times he would leave the female for five minutes, and strut with straightened legs round the vase, wagging his abdomen. Now and then he would remain perfectly still with the palpus withdrawn, or play with the palpi of the female, while she seemed in a comatose state. He would then renew the union with undiminished vigour, appearing on each occasion less desirous of changing his position. I left them at 12–30 a.m. and returned at 7 a.m. The male was still using his right palpus. I saw no application of the left palpus, but have no doubt that it was employed during the night, as in other cases. I have not observed the pairing ever interrupted by a fresh collection of semen, although there is no reason to think this may not occur. The duration of pairing is long; but I am inclined to think it is more dependent on the difficulty in inserting the palpus than on sexual endurance. The impregnation appeared to take place when the male retained his palpi in front of the bursa copulatrices for about thirty seconds, which was frequently the case.” There are occasions, however, when a very different sequel attends this dalliance. In one instance, for example, Mr. Campbell placed a pair together, and at once the male began to pay his addresses. “Shortly afterwards he rapidly applied one of his palpi to the female ... apparently with her consent.” Five hours later “he charged her, tore away two legs ... and began to suck one, using the mandibles to hold the limb as a human being would a stick of asparagus.” It is not surprising to find she died an hour afterwards. An examination of her remains brought to light the fact that she was not mature. But this does not apparently explain the ferocity of her partner, for this investigator on two other occasions saw males similarly dismember their spouses an hour or so after impregnation. This horrid feast cannot have been prompted by hunger, for one of these males had, but a few hours previously, eaten a daddy-long-legs and two blow-flies. Only twice did this investigator see a female of this species drive away a male, and in each case immediately after union. “On the other hand,” he says, “I have kept an adult pair together from the 22nd of August to the 28th of October, and they lived in perfect amity. The male never ceased paying unrequited attentions except to feed.” It will have been remarked that the behaviour of this species in regard to mating differs conspicuously from the accounts of observations on other species, wherein the aggressive instincts are displayed by the female. Mr. Campbell, commenting on these facts, remarks that such conduct is just what one would expect from creatures which lead solitary lives, and must have “come to regard weaker forms of animal life as food, or as an inconvenience, if we except its young or its mate when in the act of pairing.” Instincts which are habitually practised throughout the greater portion of the life of the species, and on which existence depends, would scarcely be suspended for a longer period than necessary for sexual union. Spiders frequently eat one another, and such an occurrence after pairing is only curious if considered apart from their habits. When the sexual desire is satisfied, their actions would again be directed by the dominant instinct of destruction.

It is to be noticed that the attack, when made by a female, often immediately follows the sexual union, while in the case where males assume the aggressive it takes place some time afterwards. Mr. Campbell explains this by the supposition that the action of the female, when satiated, would be precipitated by the threatened and unacceptable continued application of the hard, spiny palpus, while the more lasting desire of the male would have to subside before he became directed by another instinct. By that time, other attractions, if not his wandering disposition, would take him away from the web.

The fact that male Spiders are comparatively rare is perhaps explained by the fact that they are very short-lived; they probably die soon after pairing—even if they are not eaten! The snares they spin, it is to be noted, are very imperfect, though curiously enough, when young they make perfect snares on a small scale.