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CHAPTER VI.

SPIDERS AND SCORPIONS.

Emotions.

THE emotional life of spiders, so far as we can observe it as expressed in their actions, seems to be divided between sexual passion (including maternal affection) and the sterner feelings incidental to their fiercely predatory habits. But the emotions, although apparently few and simple in character, are exceedingly strong in force. In many species the male spider in conducting his courtship has to incur an amount of personal danger at the hands. (and jaws) of his terrific spouse, which might well daunt the courage of a Leander. Ridiculously small and weak in build, the males of these species can only conduct the rites of marriage with their enormous and voracious brides by a process of active manoeuvring, which if unsuccessful is certain to cost them their lives. Yet their sexual emotions are so strong that, as proved by the continuance of the species, no amount of personal risk is sufficient to deter them from giving these emotions full play. There is no other case in the animal kingdom where courtship is attended with any approach to the gravity of danger that is here observable. Among many animals the males have to meet a certain amount of inconvenience from the coquetry or disinclination of the females; but here the coquetry and disinclination has passed into the hungry determination of a ferocious giantess. The case, therefore, because unique, is of interest from an evolutionary point of view. We can see a direct advantage to species from the danger incurred by males on account of mutual jealousy; for this, giving rise to what Mr. Darwin has

called the law of battle,' must obviously be a constant source of the creation and the maintenance of specific proficiency; the law of battle determines that only the strongest and most courageous males shall breed. But the benefit to species is not so obvious where the danger of courtship arises from the side of the female. Still, that there must be some benefit is obvious, seeing that the whole structure of the male, if we take that of the female as the original type, has been greatly modified with reference to this danger: had the latter been wholly useless, either it would not have been allowed to arise, or the species must have become extinct. The only suggestion I can make to meet this aberrant case is that the courage and determination required of the male, besides being no doubt of use to him in other relations in life, may be of benefit to the species by instilling these qualities into the psychology both of his male and female descendants.

The courage and rapacity of spiders as a class are too well and generally known to require special illustration. One instance, however, may be quoted to show the strength of their maternal emotions. Bonnet threw a spider with her bag of eggs into the pit of an ant-lion. The latter seized the eggs and tore them away from the spider; but although Bonnet forced her out of the pit, she returned, and chose to be dragged in and buried alive rather than leave her charge.

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The only other point that occurs to me with reference to the emotions of spiders is the somewhat remarkable one concerning their apparent fondness of music. The testimony is so varied and abundant on this matter that we can scarcely doubt the truth of the facts. These simply are that spiders-or at any rate some species or individuals -approach a sounding musical instrument, especially when the music is tender and not too loud.' They usually approach as near as possible, often letting themselves down from the ceiling of the room by a line of web, and remain suspended above the instrument. Should the music become loud, they often again retreat. Professor C. Reclain, during a concert at Leipsic, saw a spider descend in this way from one of the chandeliers while a violin solo

was being played; but as soon as the orchestra began to sound it quickly ran back again. Similar observations have been published by Rabigot, Simonius, von Hartmann, and others.

A highly probable explanation of these facts has recently been given by Mr. C. V. Boys, which relieves us of the necessity of imputing to animals so low in the scale any rudiment of æsthetic emotion as aroused by musical tones. As the observation is an interesting one, I shall quote it in extenso :—

Having made some observations on the garden spider which are I believe new, I send a short account of them, in the hope that they may be of interest to the readers of Nature.

Last autumn, while watching some spiders spinning their beautiful geometrical webs, it occurred to me to try what effect a tuning-fork would have upon them. On sounding an A fork, and lightly touching with it any leaf or other support of the web, or any portion of the web itself, I found that the spider, if at the centre of the web, rapidly slues round so as to face the direction of the fork, feeling with its fore-feet along which radial thread the vibration travels. Having become satisfied on this point, it next darts along that thread till it reaches either the fork itself or a junction of two or more threads, the right one of which it instantly determines as before. If the fork is not removed when the spider has arrived it seems to have the same charm as any fly; for the spider seizes it, embraces it, and runs about on the legs of the fork as often as it is made to sound, never seeming to learn by experience that other things may buzz besides its natural food.

If the spider is not at the centre of the web at the time that the fork is applied, it cannot tell which way to go until it has been to the centre to ascertain which radial thread is vibrating, unless of course it should happen to be on that particular thread, or on a stretched supporting thread in contact with the fork.

If, when a spider has been enticed to the edge of the web the fork is withdrawn, and then gradually brought near, the spider is aware of its presence and of its direction, and reaches out as far as possible in the direction of the fork; but if a sounding fork is gradually brought near a spider that has not been disturbed, but which is waiting as usual in the middle of

1 Body and Mind, p. 275.

the web, then, instead of reaching out towards the fork, the spider instantly drops-at the end of a thread, of course. If under these conditions the fork is made to touch any part of the web, the spider is aware of the fact, and climbs the thread and reaches the fork with marvellous rapidity. The spider never leaves the centre of the web without a thread along which to travel back. If after enticing a spider out we cut this thread with a pair of scissors, the spider seems to be unable to get back without doing considerable damage to the web, generally gumming together the sticky parallel threads in groups of three and four.

By means of a tuning-fork a spider may be made to eat what it would otherwise avoid. I took a fly that had been drowned in paraffin and put it into a spider's web, and then attracted the spider by touching the fly with a fork. When the spider had come to the conclusion that it was not suitable food, and was leaving it, I touched the fly again. This had the same effect as before, and as often as the spider began to leave the fly I again touched it, and by this means compelled the spider to eat a large portion of the fly.

The few house-spiders that I have found do not seem to appreciate the tuning-fork, but retreat into their hiding-places as when frightened; yet the supposed fondness of spiders for music must surely have some connection with these observations; and when they come out to listen, is it not that they cannot tell which way to proceed?

The few observations that I have made are necessarily imperfect, but I send them, as they afford a method which might lead a naturalist to notice habits otherwise difficult to observe, and so to arrive at conclusions which I in my ignorance of natural history must leave to others.1

General Habits.

Coming now to general habits, our attention is claimed by the only general habit that is of interest-namely, that of web-building. The instinct of constructing nets for the capture of prey occurs in no other class of animals, while in spiders it not only attains to an extraordinary degree of perfection (so that, in the opinion of some geometers, the instinct is not less wonderful in this respect than is that displayed by the hive-bee in the con

1 Nature, xxiii., pp. 149-50.

struction of its cells), but also ramifies into a number of diverse directions. Thus we have, in different species, wide open networks spread between the branches of bushes, &c., closely woven textures in the corners of buildings, earth tubes lined with silk, the strong muslin-like snare of the Mygale, which, as first noticed by Madame Merian,1 and since confirmed by Bates, is able to retain a struggling humming-bird while this most beautiful animal in creation is being devoured by the most repulsive; and many other varieties might be mentioned. It may at first sight appear somewhat remarkable that this instinct of spreading snares should on the one hand occur only in one class of the animal kingdom, while on the other hand, in the class where it does occur, it should attain such extreme perfection, and run into so much variety. But we must here remember that the development of the instinct obviously depends upon the presence of a web-secreting apparatus, which is a comparatively rare anatomical feature. In caterpillars, which are not predaceous, the web is used only for the purposes of protection and locomotion; and it is easy to see that the spreading of snares would here be of no use to the animals. But in spiders, of course, the case is otherwise. Once granting the power of forming a web, and it is evident that there is much potential service to which this power may be put with reference to the voracious habits of the animal; and therefore it is not to be wondered that both the anatomical structures and their correlated instincts should attain to extreme perfection in sundry lines of development. The origin of the webbuilding structure was probably due to the use of the web for purposes of locomotion or of cocoon-spinning, as we see it still so used in the same way that it is used by caterpillars for descending from heights, and in the case of the gossamer spider for travelling immense distances through the air. As the anatomical structures in question differ very greatly in the case of spiders and in that of caterpillars, we may wonder why analogous if not homolo

1 Naturalist on the Amazon, p. 83.

2 For many other confirmations see Sir E. Tennent, Nat. Hist. Ceylon, pp. 468-69.