Spider Venoms and Their Effect

Abstract

In principle, with the exception of some groups of spiders which have no venom glands at all (e.g. Uloboridae and Holarchaea) all spiders with any kind of venom apparatus must be considered as venomous, if not always for man, then perhaps for other animals, or at least for insects, their usual prey. Vachon (1968) considered only about 100 spider species as actually dangerous to man. According to Sutherland (1981), about 100 species of Australian spiders may bite man, however, this does not, of course, mean that all of them are dangerous. A spider is not necessarily venomous to man due to different reasons: (1) their venom does not contain toxic fractions which affect mankind; (2) the quantity of the venom which the spider injects is insufficient; (3) their chelicerae are not strong enough to penetrate the human skin; (4) they are too timid to come into contact with man; (5) they have not had the opportunity of contact due to their lifestyle, i.e. contact may have been accidental, therefore their venomosity has not been recorded. Examples of the last consideration are the “new” venomous species which are still being “discovered”, e.g. the theridiid Steatoda paykulliana (Maretić et al. 1964) or the theraphosid Pterinochilus sp. (Maretić 1967). According to Russell and Gertsch (1982) the number of such new venomous spiders in the United States has increased to about 60 species.