All scorpions have a venomous sting-
but the vast majority of the species do not represent a serious threat to humans and in most cases healthy adults do not need any medical treatment after being stung.Only about 25 species are known to have venom capable of killing a human.:1 In some parts of the world with highly venomous species human fatalities regularly occur, primarily in areas with limited access to medical treatmen.
scorpion venom
Introduction
Autotomy is the process by which some animals voluntarily shed or detach a body part, usually as an anti-predator defense mechanism. In order to be considered autotomy, the process of shedding or detachment must be provoked by external stimuli, achieved by an intrinsic mechanism, and mediated by the nervous system .
Autotomy occurs along permanent sites of weakness, cleavage planes that permit a clean break when a body part is detached, with anatomical features that minimize trauma and promote rapid sealing of the fluid compartment, leading to swift closure and healing of the wound .Among invertebrates, autotomy is characterized by limited loss of hemolymph from either the stump or discarded appendage . The separation of an appendage from the body at a site of weakness, when pulled by an outside agent, has been termed autospasy by some authors (e.g. , and is here considered synonymous with autotom.
The detached body part, e.g., the tail of lizards or the legs of arthropods , may also act as a distraction, engaging the predator’s attention by spontaneously twitching, writhing or wriggling, while the animal escapes. The incidence of autotomy in natural populations may be determined by predation efficiency and intensity, anatomical mechanisms, microhabitat preference, sex and ontogenetic differences, intraspecific aggression and the use of other defense mechanisms.
Autotomy of a body part is an effective anti-predator defense mechanism that evolved independently in various taxa . The phenomenon has been recorded in cnidarians, annelids, molluscs, echinoderms, arthropods and vertebrates . Among arthropods, autotomy has been reported in crustaceans, hexapods, chilopods and arachnids, always involving the loss of appendages, usually legs
Among arachnids, autotomy of the legs has been observed in Opiliones (harvestmen), Acari (mites and ticks), and Araneae (spiders) , but was not reported to occur in scorpions. Autotomy of the metasoma, the posterior part of the opisthosoma, or ‘tail’, was recently reported in several species of the Neotropical buthid scorpion genus Ananteris Thorell, 1891 , which currently comprises 79 species of small (9 to 42 mm in total adult length), cryptic, terrestrial scorpions inhabiting the tropical forests of northern South America, from Costa Rica to Argentina . These reports represent the first cases of autotomy of opisthosoma (abdomen) in arthropods.
scorpion venom:Based on observations in the field and laboratory, examination of material in museum collections, and scanning electron microscopy, we document autotomy of the metasoma in fourteen species of the genus, and provide behavioral observations with the following objectives: (1) to verify that metasomal autotomy in Ananteris is provoked by external stimuli, achieved by an intrinsic mechanism, and mediated by the nervous system; (2) to confirm that cleavage planes are present in the metasoma of Ananteris; (3) to assess whether the incidence of autotomy differs between the sexes; and (4) to provide data about post-autotomy behavior which may illuminate the functional significance of metasomal autotomy.
scorpion venom
