Certain isolated observations on captive jumping spiders led these observers to suspect that the mating habits were unusual and worthy of accurate investigation, and they laid their plans accordingly, taking their summer holiday a month earlier than usual, so as to miss nothing of the pairing season, and including in their party an artist whose drawings should furnish an indubitable record of the attitudes assumed by the male spiders in their evolutions.
On arriving at their destination they found a small species, Saitis pulex, with no great claims to remarkable beauty, mature, and ready to pair. A female was placed in one of the experimental boxes which had been provided in advance, and a male was admitted on the following day. He sighted her at a distance of twelve inches, and showing signs of excitement, advanced to within about four inches and then performed a most ludicrous dance—something in the nature of a “highland fling,” in a semicircle before her, she, in the meantime, moving in such a manner as to keep him always in view. His exact behaviour was this: he extended all the legs—and the palp—on the left side, folding the first two legs and the palp of the right side under him, and leaning over sideways so far as nearly to lose his balance, and in this attitude he sidled along towards the lowered (right) side till he had described an arc of about two inches; then the position was instantly reversed, the right legs being extended and the left folded under, and the arc retraced. A male was seen to repeat this performance 111 times! He then approached nearer and when almost within reach “whirled madly around and around her, she joining and whirling with him,” after which she accepted him as a mate.
The next species to engage attention was an Icius. It was noteworthy that although the neighbourhood was well known to the experimenters they had never met with this spider before, but for a few days it swarmed on the fences just as birds are known to assemble from all quarters for the so-called “love dances.” After the mating season the spiders wandered off into the woods again and were seen no more.
Fig. 10. A male Attid spider (Astia vittata) dancing before the female. (After Peckham.)
The performance was much as before, but the spiders assumed different attitudes. The female lay flat on the ground with her front legs raised; the male danced on the six hind legs, with the front legs lowered and meeting at the tips. The males of this species were exceedingly quarrelsome, sparring frantically whenever they met, but their battles were entirely bloodless. “Indeed,” say the observers, “having watched hundreds of seemingly terrible battles between the males of this and other species, the conclusion has been forced upon us that they are all sham affairs, gotten up for the purpose of displaying before the females, who commonly stand by, interested spectators.” In the case of one species, after two weeks of hard fighting between the males, the Peckhams were unable to discover one wounded warrior. The females, on the other hand, were often really formidable. Phidippus morsitans is an example. The male has handsome front legs, thickly fringed with white hairs, and he displays these to the best advantage in his love antics. Two males supplied in succession to one female “had offered her only the merest civilities when she leaped upon them and killed them.”
In the case of most of the spiders whose love-dances were investigated, the chief ornamentation of the male consisted of fringes of white or coloured hairs on the face, the palps, and the front legs, and they kept these parts always before the females, displaying their glories to the utmost advantage. The male of Habrocestum splendens, however, possesses an extremely brilliant abdomen, and, lest anything of its beauty should be lost upon the object of his admiration, he varies the ordinary performance in a remarkable manner. He often pauses in the dance, and, raising his abdomen, “strikes an attitude” in which he remains motionless for half a minute. Moreover he frequently turns his back on the female—a most unusual occurrence in the course of these antics.
The males of one species, Philaeus militaris, were observed to capture and keep guard over young females, which they imprisoned in webs spun for the purpose until they had undergone their last moult and were mature, chasing away all intruders in the interval.