Poisonous spiders in Czech republic

So, night shadow, in form of poisonous warm-loving insect, became a reality even for relative cold Czech Republic. Its warmest area, South Moravia, reminds, with its very favourable climate, Mediterranean. Frankly speaking, lasting and quite  dangerous inhabitant presents viper (we have to pay attention, while walking through nature), but we meet spiders more often, so the immagination of poisonous spider is much more frightened for us.

The migration brought just several new sorts of insect, most surprising from these is striped cross-spider (Argiope bruennichi), especially with his exotic appearance, being suspected of the first look. Yellow-black stripes, interwoven with thin white small stripes, maximal 15 mm great (in case of female, she is much more bigger as male, and her colouring is much more expressive). This spider was, even 50 years ago, a great rarity in Central Europe. Anyway, with consequent getting warm, this insect moved later into areas bear to North Sea. In Czech Republic, this spider appeared in 1990, and his population is well to be watched since 1991, when he moved from South Moravia to other areas. This representant of insect empire is using relatively strong poison, in order to kill his plunder. Nevertheless, he could not injure the people, as his mandibles cannot penetrate people´s skin. So, his poison is not effective and dangerous. It is true that striped cross-spider is often taken for life dangerous insect (especially thanks to this gaudy colouring). Nevertheless, really dangerous spider is Cheiracanthium punctorium. This spider settled (similarly as striped cross-spider, influenced by global warming stage) in rather warm areas of Czech Republic, where it moved from south France. In contradistinction to other local insect sorts, this spider is surpassing with his colouring, being light transparent in yellow and green shade. This fact pays attention that something is not O.K. In fact, this spider is one of most poisonous and biggest (1,5-4cm) spiders in Europe. He could cause pains with his stinging but he can kill seldom. This argument can be tranquillizing but you have to pay an attention that during your summer sunshine on blowing meadow you could meet a creature, being able to cause you painly stinging or local paralysis of extremities, expressive indisposition, despondency or very unpleasant anxiety feelings. Nevertheless, the consequences of  stinging are very individual, the victim has to wait for unpleasant 24 hours, when poison effects are slowly diminuished. So, there are living ten sorts of this repelling insect in Czech Republic, dividing each other according type of territory. However, this spider Cheiracanthium punctorium belong to so called expansive sort, and its population does not diminuish at all. We can find this insect mostly in meadow overgrown. Here, the spider constructs his nest (cocoon) on dry grass blades, this grass reminds its original home. Despite the fact that possible attacks of this spider are unpleasant, there is no condition that meeting this insect causes attack. It is true that most aggresive reaction could be expected of females, who defend active their ova-cocoons. Somebody could compare the effects of spider poison to vasp stinging, but, anyway, psychical part is functioning: the spider stung! Most threatened part of population, there are alergic persons, as usual. However, their reaction of the organism to unknown poisonous substance could not be estimated in advance. The spiders of Cheiracanthium are greatest bugbears in Europe. Anyway, its only advantage consists in a fact that this poisonous representant is big – it has greatest dimensions, making comparison to remaining sorts of insect, so it is very good seen at first look, and informs in advance that we have to pay attention and have to be carefull.

Text: Jan Chaloupka