Through a pocket lens

by Henry Scherren

The spider may be watched at leisure, if put into a bottle of moderate size, the top of which should be covered with muslin or calico to prevent escape. Here it is fairly easy to bring the pocket lens into play, and to distinguish the different parts of the animal. The eyes, and their arrangement, should be particularly noticed.

Fig. 51.—Anchorage of Web.

Blackwall, in support of the position that in making their webs spiders are guided by touch rather than sight, says, ‘Various species, when confined in spacious glass jars placed in situations absolutely impervious to light, construct nets which do not exhibit the slightest irregularity of plan or defect of structure[31].’ My specimens have always been kept in the light, and in small bottles rather than spacious jars, but I have never seen spiders attempt to make a geometrical web under such conditions.

A bottle which for some months served as a prison-house for a Garden Spider now stands on my writing-table. Its sides are marked by hundreds of ‘anchorages’—but the threads cross and recross, forming in some parts a kind of sheet, and in others a tangled mass. Some of these threads must have been covered with viscid secretion, for flies were limed, and so fell a prey to the spider. Their dried skins are dotted about among the threads, and the spider itself perished long ago from cold. But I keep the bottle as a curiosity, to show that these spiders do not always make geometrical webs.

When one has a Garden Spider in a bottle, it may be observed to practise a curious and very effective method of disabling its prey. If a bluebottle or any other large fly be dropped and entangled among the threads, the spider will envelop it in a sheet of web. This is how Blackwall describes the operation: ‘Causing the victim to rotate by the action of the third pair of legs and the palps, the first pair of legs also being frequently employed in a similar manner, they extend the spinners laterally, and applying to them alternately the sustentaculum of each posterior leg, they seize and draw out numerous fine lines in the form of a fillet, which they attach to their revolving prey, and thus involve it in a dense covering of silk from one extremity to the other. By means of this stratagem they are capable of overcoming formidable and powerful insects, such as wasps, bees, and even large beetles[32].’

The operation does not occupy much time; in a very few minutes the fly is swathed in a silky covering as completely as an Egyptian mummy in its linen folds. Of course resistance, much less attack, is out of the question, and when it is thus rendered powerless for harm the spider proceeds with its meal.

The sustentac´ulum—or support—is a strong movable spine near the end of the tarsus, on the under side of each of the last pair of legs. These spines act in opposition to the claws, and thus these animals are enabled to hold with a firm grasp such lines as they have occasion to draw from their spinners with the feet of the hind legs, and such also as they design to attach themselves to.

With regard to this method of swathing prey, Hudson[33] says of an Argentine spider, ‘that its intelligence has supplemented this instinctive procedure with a very curious and unique habit. The Pholcus, in spite of its size, is a weak creature, possessing little venom to dispatch its prey with, so that it makes a long and laborious task of killing a fly. A fly, when caught in a web, is a noisy creature, and it thus happens that when the Daddy longlegs—as Anglo-Argentines have dubbed this species—succeeds in snaring a captive, the shrill outrageous cries of the victim are heard for a long time—often for ten or twelve minutes. This noise greatly excites other spiders in the vicinity, and presently they are seen quitting their webs and hurrying to the scene of conflict. Sometimes the captor is driven off, and then the strongest or most daring spider carries away the fly. But where a large colony are allowed to continue for a long time in undisturbed possession of a ceiling, when one has caught a fly he proceeds rapidly to throw a covering of web over it, then, cutting it away, drops it down and lets it hang suspended by a line at a distance of two or three feet from the ceiling. The other spiders arrive on the scene, and after a short investigation retreat to their own webs, and when the coast is clear our spider proceeds to draw up the captive fly, which is by this time exhausted with its struggles.’

In this connexion Hudson notes that spiders are attracted by the sound of the vibration of a string or wire, thinking it made by an insect that has been caught; and he says that the stories of tame spiders are founded on a misunderstanding of the motive that brings the animal down. We may well doubt if spiders are attracted by music, but that some spiders possess a sense of hearing, or something analogous thereto, seems to be proved by the existence of stridulating organs in certain members of the group.