Harvesting Ants and Trap-Door Spiders / Notes and Observations on Their Habits and Dwellings

by John Traherne Moggridge

I will now relate what I saw on one of these occasions,[65] for there has been much speculation as to the manner in which the spider clings to the door and offers the determined resistance which is experienced.

[65] Mrs. Boyle was the first to witness this curious sight, and my description of the resistance of the spider is almost an exact repetition of hers to me. It is curious also that, following her indications, I found the very nest and spider on which she had made her observations, and every detail recurred again though several days had elapsed between her visit and mine.

No sooner had I gently touched the door with the point of a penknife than it was drawn slowly downwards, with a movement which reminded me of the tightening of a limpet on a sea-rock, so that the crown which at first projected a little way above, finally lay a little below the surface of the soil. I then contrived to raise the door very gradually, despite the strenuous efforts of the occupant, till at length I was just able to see into the nest, and to distinguish the spider holding on to the door with all her might, lying back downwards, with her fangs and all her claws driven into the silk lining of the under surface of the door. The body of the spider was placed across, and filled up, the tube, the head being away from the hinge, and she obtained an additional purchase in this way by blocking up the entrance.

I did not force the spider to release her hold, but, by a rapid stroke with a long-bladed knife, cut out the upper part of the tube with the surrounding mass of soil, and thus secured the trap-door and its owner. This specimen is represented at fig. C, [Plate VIII.], where the pin-point holes made by the claws may be seen in pairs round the whole circumference of the flatter portion of the lower surface of the door except on the side next to the hinge.

Whenever a spider resists in this way she must make these holes, but I have very rarely seen them in other nests; this may perhaps be accounted for by their having been effaced by the action of moisture which would stretch the silk. However this may be, this specimen showed the claw marks quite distinctly on my return to England after the lapse of several weeks.

Much has been written about these marks, which are frequently spoken of as holes purposely made in the silk in order to give the spider a better purchase. It has also been stated that two holes may be seen in the silk of the tube near the mouth on the side away from the hinge, but these I have never been able to find. The door of nest A in [Plate VIII.] is rather abnormal, as it is made up of two doors, the smaller one being spun into the top of the one now in use. This is, I believe, an abnormal and rather clumsy example of the ordinary way of enlarging the nest, but of this we shall see more when we come to speak of the construction and repairing of these nests generally.

Fig. B in this plate represents a moss-covered sod pierced by the tube of a nest, the door of which is entirely concealed from view, and only discovered when opened as at B 1.

This nest was found accidentally by Mr. Robert Lightbody, who kindly brought it to me, its presence having been betrayed by the tube, which he happened to cut through in digging up a plant. The moss on the door grew as vigorously, and had in every way the same appearance, as that which was rooted in the surrounding earth; and so perfect was the deception that I found it impossible to detect the position of the closed trap even when holding it in my hand. There can be no doubt that many nests escape observation in this way, and the artifice is the more surprising because there is strong reason to believe that this beautiful door-garden is deliberately planted with moss by the spider, and not the effect of a mere chance growth. I shall adduce evidence in support of this statement by-and-by.

I alluded to the nest C ([Plate VIII.]) when speaking of the claw marks which it exhibits, and that figured at D and D 1 in this plate is merely an instance of a good example of this type. I have taken nests of N. cæmentaria both at Cannes and Mentone, and have little doubt that this species will be discovered at many points along the Riviera. I detected two abandoned nests of the cork type, which I fully expect had belonged to N. cæmentaria, in an enclosed space called the Campagne de Garonne in Marseilles itself. These nests lay in the little mound of undisturbed earth between the divided trunks of the small olive-trees, and I do not doubt that if I had had time to search I should have discovered more nests, and perhaps others which were still tenanted.