Stinger

For other uses, see Stinger (disambiguation).

Wasp sting, with droplet of venom.

A stinger, or sting, is a sharp organ found in various animals (typically arthropods) capable of injecting venom, usually by piercing the epidermis of another animal. Technically, a stinger is the part of an insect or animal that holds a sting, where a sting is the pointed organ. In common usage, stinger is a colloquialism for sting. A sting differs from other piercing structures in that it pierces by its own action and injects venom, as opposed to teeth, which pierce by the force of opposing jaws. Stinging hairs which actively inject venom on plants such as stinging nettles are also sometimes known as stings, but not stingers.

An insect bite or sting is a break in the skin or puncture caused by an insect and complicated by introduction of the insect's saliva, venom, or excretory products. Specific components of these substances are believed to give rise to an allergic reaction, which in turn produces skin lesions that may vary from a small itching wheal, or slightly elevated area of the skin; to large areas of inflamed skin covered by vesicles and crusted lesions.

Stinging insects produce a painful swelling of the skin, the severity of the lesion varying according to the location of the sting and the identity of the insect. Many species of bees and wasps have two poison glands, one gland secreting a toxin in which formic acid is one recognized constituent, and the other secreting an alkaline neurotoxin; acting independently, each toxin is rather mild, but when they are injected together through the sting, the combination has strong irritating properties. In a small number of cases the second occasion of a bee or wasp sting causes a severe allergic reaction known as anaphylaxis.

Hornets, some ants, centipedes, and scorpions also sting. Some insects leave their stinger in the wound. Multiple stings may give rise to severe systemic symptoms and in rare instances may even lead to death.

Arthropods

Yellowjacket sting in its sheath in the scanning electron microscope.

Among arthropods, a sting is a sharp organ, often connected with a venom gland, adapted to inflict a wound by piercing, as with the caudal sting of a scorpion. Stings are usually located at the rear of the animal. Animals with stings include bees, wasps (including hornets), scorpions and some groups of ants.

Scorpion's stinger.

Unlike most other stings, honey bee workers' stings (a modified ovipositor as in other stinging Hymenoptera) are strongly barbed and lodge in the flesh of mammals upon use, tearing free from the honey bee's body, leading to the bee's death within minutes. The sting has its own ganglion, and it continues to saw into the target's flesh and release venom for several minutes. This trait is of obvious disadvantage to the individual but protects the hive from attacks by large animals. The barbs ensure that a honey bee's attack is only suicidal if the attacker is a relatively large animal; bees can sting other insects repeatedly without dying. The sting of nearly all other bees and other sting-bearing organisms is not barbed and can be used to sting mammals repeatedly. The stingers of yellowjacket wasps and the Mexican honey wasp are so small that they do not cause the sting apparatus to pull free. The stingers of some wasps, such as those of the Polistes versicolor, contain relatively large amounts of 5-hydroxytryptamine (5-HT) in its venoms. The 5-HT in these venoms has been found to play at least two roles: one as a pain-producing agent and the other in the distribution and penetration of the paralyzing components to vulnerable sites in the offender. This helps in the rapid immobilization of the animal or of the certain body parts of the animal receiving the venom.

Other animals

Organs that perform similar functions in non-arthropods are often referred to as "stings." These organs include the modified dermal denticle of the stingray, the venomous spurs on the hind legs of the male platypus, and the cnidocyte tentacles of the jellyfish.

The term sting was historically often used for the fang of a snake, although this usage is uncommon today. Snakes are said, correctly, to bite, not sting.

Plants

Modified trichomes function as urticating hairs in the stinging nettle, Urtica dioica.

In plants, the term "sting" is normally used as a verb, but occasionally used as a noun refer to urticating hairs, sharp-pointed hollow hairs seated on a gland which secretes an acrid fluid, as in species of Urtica (nettles). The points of these hairs are brittle and break off easily, leaving a sharp point through which the fluid is injected. On the other hand, the bristles of some cacti are recovered by retrorse barbs called glochids (like foxtail spikelets), which prevent bristles from falling once they sting.

See also

• Bee sting
• Cnidocyte
• Chelicerae
• Forcipules
• Insect bite
• Schmidt Sting Pain Index
• Starr sting pain scale

External links

• Media related to at Wikimedia Commons