Southern Europe possesses a congener of this spider in Latrodectus 13–guttatus, the well-known “Malmignatte,” which is also considered extremely poisonous. The Royal Academy of Medicine and Surgery at Barcelona appointed Dr. Graells, in 1833, to inquire into the effects of the bite of this spider, cases of which had become exceedingly frequent. He found a curious correspondence between the frequency of these cases and the advent of migratory locusts, which the spider successfully attacked. In his report[[286]] he details the symptoms in certain unquestionably authentic cases. There was a double puncture, surrounded by red circles, the region of the wound afterwards swelling greatly. The pain and swelling extended over the whole limb, and often to the body, and convulsions occurred, followed by great prostration and collapse. All the patients eventually recovered, their cure being heralded by profuse perspiration.
It must be mentioned, however, that the eminent Arachnologist M. Lucas states that he has several times allowed himself to be bitten by this identical spider without any ill effects.
The testimony is thus conflicting in this case also. It is impossible, however, to believe that there is no basis in fact for the poisonous reputation of a comparatively insignificant-looking spider in so many widely separated parts of the world, supported as it is by certain well-substantiated cases. The variable effects of its bite may find a partial explanation in a variation in the strength of its venom at different seasons, and it has already been mentioned that the injection of poison into its victim is a voluntary act, and does not necessarily accompany its bite. Among the species regarded as especially venomous must be mentioned Phidippus morsitans, one of the larger of the Attidae.
It is exceedingly likely that the bite of the large tropical Aviculariidae is really formidable. They appear, however, more anxious to escape than to show fight, and we possess little reliable information with regard to them. Doleschall shut up small birds with two West Indian species, and death followed their bite almost immediately. Ten days’ starvation appeared to weaken the venom, for a bird bitten by a spider fasting for that period recovered after an indisposition of six hours.
Most Arachnologists have recorded experiments with regard to the venom of the commoner European species, with equally conflicting results. Blackwall came to the conclusion that loss of blood, and not poison, caused the death of spider-bitten insects. He could not himself distinguish a spider bite from the prick of a needle inflicted upon his hand at the same time. Bees, wasps, and grasshoppers survived the bite about as long as other insects of the same species outlived a needle-prick in the same part of the body. Walckenaer’s experience was of the same nature. Bertkau, however, when bitten in the hand, felt clear indications of an irritant poison in the wound. The hairs of some of the large hairy species of the Aviculariidae possess poisonous properties. They are readily parted with, and when the animal is touched by the hand considerable irritation is set up.
Fertility of Spiders.—Spiders vary greatly in the average number of eggs laid by different species, and within the limits of each species there is a very considerable variation in fertility. As a rule it appears that the large and vigorous spiders are more prolific than the smaller and weaker members of the order. Were all the facts before us, however, we should no doubt find that the number of eggs laid bore a direct proportion, not to the size of the species, but to the dangers to which the young of that species are exposed. Where the total numerical strength of a species is fairly stationary, such a proportion must of course exist. Some species, no doubt, are tending to become extinct, while others are increasing in numerical importance. As a general rule, however, it is safe to infer that, if a species is especially prolific, special dangers attend the rearing of the young. The largest of North American Epeirids, Argiope cophinaria,[[287]] constructs a cocoon containing, on an average, 1150 eggs. As many as 2200 have been counted in exceptional cases. Even this number is exceeded in the case of some of the great Aviculariidae. Theraphosa leblondi deposits as many as 3000 eggs. The large European Epeirids, E. quadrata and E. diademata, lay about 600 eggs, those of Lycosa narbonensis reaching about the same number. Those American spiders which have been described as stringing up a series of cocoons in their webs usually attain about the same aggregate, the eggs being less numerous in each cocoon.
These are examples of fairly large and fertile spiders. In the case of other species the number of eggs laid is exceedingly small. Ero furcata makes a single cocoon containing six eggs. Synageles picata, an ant-like Attid, lays only three. Oonops pulcher constructs several cocoons, but each contains only two eggs. The eggs of Cave-spiders, and such as live in dark and damp places, are generally few in number. Anthrobia mammouthia, for example, an inhabitant of the great American caves, deposits only from two to five eggs.
Our knowledge of the special perils which beset particular species is so incomplete that we are often at a loss for the reason of this great inequality in fertility. For instance, how does Synageles picata maintain its numerical strength by laying only three eggs, when, as M‘Cook points out, its resemblance to the ant, though advantageous to the adult spider, affords no protection to the egg? Our knowledge must be greatly extended before we are able to account for particular cases. Many influences hostile to spiders as a group are, however, well known, and we may here enumerate them.
Natural Enemies.—The precautions taken by the mother in constructing the cocoon render the inclemency of the weather very much less destructive to the eggs than to the newly-hatched young. Nevertheless, among spiders inhabiting swampy regions great havoc is wrought by the occasional wholesale swamping of the cocoons by floods. Professor Wilder considers the great fertility of Nephila plumipes necessary to counterbalance the immense destruction worked by the heavy rains upon their cocoons, which are washed in great numbers from the trees, to the leaves of which they are attached. But such exposed situations are avoided by many species, and their eggs, enclosed in their silken envelope, are well protected against the severities of the weather.
A more universal enemy to the egg is found in Ichneumon flies. On examining the cocoons of almost any species of spider, a large proportion are almost certain to be found to contain Ichneumon larvae. Mr. F. Smith, in the Transactions of the Entomological Society for 1860, describes two species, Hemeteles fasciatus and H. formosus, which are parasitic on the eggs of Agelena brunnea. They are figured in Mr. Blackwall’s book on British Spiders. Pezomachus gracilis attacks the cocoons of many kinds of American spiders, appearing to have no special preference for any particular species, while Acoloides saitidis seems to pay special attention to the eggs of certain of the Jumping-spiders, and particularly of Saitis pulex.