Urticating hair

Stinging hairs are hair-like structures, causing tiny barbs mechanically and / or by means of special agents in contact with a burning sensation. They are known mainly nettles, where they sit on the stem and the leaves of the plant. There are also in insects, including the larvae of the processionary moth, and the tarantulas stinging hairs.

Stinging hairs in plants

In a contact with stinging hairs of many nettle plants or flowers nettle plants ( or Neesia ) arise painful welts. The stinging hairs have at their head a head that is silicified and has a breaking point. If the head torn off when touched, it leaves the sharp, rigid hair. This burrows into the skin and emptied the mixture contained in it from serotonin, histamine, acetylcholine, formic acid and sodium formate. The main active ingredient, which is responsible for the wheal is not yet known. Already one ten thousandth milligrams of liquid fuel is sufficient to achieve the known effect. The base of the hair ( base) is adjacent to epidermal cells also from hypodermal cells is thus an emergence, while the actual focal hair is a single-celled trichome.

See also: Plant defense against herbivores, the " stinging hairs " in the article nettles

Stinging hairs in animals

The stinging hairs of arthropods are bristles, a component of the cuticle, chitin containing as structure-directing material.

Stinging hairs in insects

The caterpillars of some butterfly species have stinging hairs that will protect them from their predators. Among the species whose caterpillars have stinging hairs, include for example the oak processionary moth ( Thaumetopoea processionea ), easily break their stinging hairs and can be spread for miles with the wind. They contain the nettle poison Thaumetopoein and have barbs. In humans, these stinging hairs cause allergic reactions of the skin, eye irritation, and if they get into the respiratory system, symptoms such as coughing and asthmatic attacks may be the result. In strong caterpillars years - Gradation - it may be necessary to terminate the affected areas for the access of vulnerable people.

The caterpillars of other processionary moth species as well as some Trägspinnerarten as the gypsy moth ( Lymantria dispar ) and the gold After ( Euproctis chrysorrhoea ), are equipped with stinging hairs. Another butterfly, whose caterpillars have stinging hairs, the oak moth ( Lasiocampa quercus ).

Stinging hairs in spiders

Many tarantulas species also have stinging hairs. These usually sit on the abdomen of the spider. The stinging hairs on the skin cause severe itching, or, depending on the type, even burning rashes. This irritation may persist for up to one day. If the hairs get into the respiratory tract, they cause severe coughing and allergies cause swelling, which can be dangerous. Come the stinging hairs in the eye, conjunctivitis can be the result.

Stinging hairs have only the two occurring in the New World subfamilies of tarantulas that Theraphosinae and Aviculariinae. The hair is 0.3 to 0.75 mm long and have a large number of tiny barbs. The operation of the stinging hairs of the spider is not explored exactly. Scientists assume, however, that it is a purely mechanical irritation of the skin by many barbs and not a toxic effect by a spider bite or nettle venom of stinging hairs of caterpillars of the processionary moth.

The so-called Bombardier spiders can strip away the many small hairs on the upper side of the abdomen with the hind legs quickly and hurl the attacker. A cloud of fine stinging hairs then strikes the attacker. Such behavior also shows the giant Tarantula ( Theraphosa blondi ).

Although other of these tarantulas have stinging hairs, not bombard you with this, however, but an attacker stretch towards her abdomen. In case of contact, this can injure the attacker. These include many species of the genus Avicularia. Species of the genus Ephebopus have stinging hairs on the femora of their button.