NATURE NOTES

New Zealand Herald, Volume LXXI, Issue 21698, 13 January 1934, Page 1 (Supplement)

NATURE NOTES

BT J. DRTTMMOND, F.L.8., F.Z.S

WOLF SPIDERS

On a path in front of his house at Greenhithe, on the upper Auckland Harbour, Mr. J. L. P. Churchouse saw a spider that seemed different from any spiders ho had seen previously. Its body, apparently, was covered with small pimples, sot very close together. He enticed it into a flower pot, in order to examine it with a lens. Ho did not succeed, as it crawled to the cdgo of the flower pot and fell on. to the path. The impact caused about two-thirds of the pimples to drop off itis back. To his surprise he found that the pimples were not pimples, but young spiders. They ran in all directions. To discover if the adult would gather up its family, he, using a straw, worked the adulij to the place where tho young were running hither and thither. The adult seemed to take no notice of them while ho watched. He asks if it is tho practice for some spiders to carry their young on their backs.

The answer is that the spider was a female wolf-spider and that almost all female wolf-spiders carry their young on their backs. With tho official title of Lycosids, which, like their popular name, implias wolfish habits, these vagabond spiders, wandering over tho face of the earth, hunting for prey and chasing small creatures on the ground, are very plentiful. At times they may bo seen in countless thousands. There aro several hundred species, all members of the same big family, the Lycosidae. New Zealand has at least thirty species. They do not dress loudly, favouring browns and greys. They spin not, make no snares, do not invite flies to walk into their parlours, have no guile, do not pretend to be what they are not, frankly display their wolfishness, and rely on i;heir quickness and skill to keep their meal-tables well served.

The wolf-spiders' strangest domestic arrangement is the practice that surprised Mr. Churchouse. An observer was fortunate enough to see a female make a cocoon, lay its eggs, and care for its young. It was kept in a glass jar with some earth. It began by burrowing an inch deep into the earth. Making a silken cocoon inside, it laid its eggs in the cocoon, gathered the edges of the cocoon, and pulled them over the eggs. It attached the cocoon to spinnerets at the end of its body and emerged from the burrow, carrying the cocoon behind it, bumping the cocoon on the ground in its search for prey. Removal of the cocoon was resisted by the spider. When the cocoon was taken away the spider became distressed, and searched for it. On its return after an hour and a half, it was received eagerly, and was again attached to the end of the body.

As soon as the young are hatched they climb on to their parent's back. An accident may dislodge them. They scatter in panic. On the danger passing, they return to their parent and swarm up its legs to their former position, hanging on precariously by the skin of their teeth, a permissible phrase in respect to creatures that have no need for teeth. Thy are restless: little things. Sometimes they run all over their parent, covering every part exce'pt the legs and the eyes. If one gets over an eye, the parent gently sweeps it off with one leg. In case of accidental dislodgment, the voung may swarm on to any other spider that tolerates them. Two or three whole families may crowd on to a s*ngle adult. The young seldom descend voluntarily, but members of a family, while the parent was drinking, jumped down to the ground.

The value a female places on its cocoon, containing precious eggs, gives an impression that there is a glimmering of intelligence in the tiny brain. Experiments show that the anxiety is automatic rather than the result of affection. A female will accept a cocoon belonging to another female. A ball of pith offered instead of a cocoon was attached by a female to the end of its body. The same action was taken with a pellet of straw and a ball of paper. A female allowed to choose between a cocoon and a ball of pith chose the cocoon after slight hesitation. A cocoon heavily weighted by a leaden shot was accepted without question. The burden was so heavy that the spider could hardly crawl, but it persevered resolutely. Failing to attach the cocoon to the spinnerets, the spideir carried it between the jaws and the third pair of legs. Half an hour was spent trying to fasten the cocoon on to the spinnerets.

Small grubs of a group of lacewing insects are parasites on young wolfspiders. They find a spider's cocoon, tear a hole in it, and wait until the spiders hatch. When the spiders are very young the parasites devour them, and undergo a change in the midst of a mass of dead young spiders. Parasitism in this form is common among insects, spiders and their allies. It would not cause particular interest in the present case except for a phase noted by Dr. David Sharp in the " Cambridge Natural History." Ho wrote: " Although these grubs are so destructive to the young wolf-spiders, the mother spider shows no hostility to it, but allows the destroying grubs to enter her bag of eggs without any opposition. In one case, the spider seemed to be so unconscious of the havoc among her young that she continued to watch over and protect the cocoon during the whole time of the parasite's development inside." As Maior R. W. G. Hingston asked readers of one ot his books, " What can wo think of the instinct of a spider that allows her young to be slowly devoured beneath her eyes?"

Wolf-spiders have attracted so much attention that their memories were tested. One was robbed of its cocoon. The spider, distressed, ivas given back its cocoon after an hour and a-half. It was accepted. The experimenter concluded that memory was sound for that short time. The cocoon was robbed again. On this occasion it was returned after three hours. The spider accepted it, but not as readily as on the first occasion. After three hours, evidently, its memory was strained. Another cocoon was removed for thirteen hours. It was then accepted. Another was accej)ted after sixteen hours. Others were kept for twenty-four hours. The owner of one of theso refused to take it back. A cocoon kept for forty-three hours seemed to be forgotten. The spider touched it with its legs, but languidly. In the end, tho spider took it back. Memory had begun to fail. Tho last cocoon was kept for forty-eight hours. The spider would not recognise it or have anything to do with it. Memory had failed completely. Affection had not continued for forty-eight hours.

Leaping spiders have better eyesight than any other spiders, but wolfspiders have nothing to complain of in this respect. Their eyes are arranged in three rows. In the front row there are four small eyes, directed forward Two largo eyes are in the ne.vc row, also directed forward. In the third row are two eyes of medium size, which look upward. By moving the body, the battery of eyes is brought to bear on different points of the compass.