title: Scorpion sheds 'tail' to escape: consequences and implications of autotomy in scorpions (Buthidae: Ananteris).
abstract: Autotomy, the voluntary shedding or detachment of a body part at a determined cleavage plane, is a common anti-predation defense mechanism in several animal taxa, including arthropods. Among arachnids, autotomy has been observed in harvestmen, mites, and spiders, always involving the loss of legs. Autotomy of the opisthosoma (abdomen) was recently reported in a single species of the Neotropical buthid scorpion genus Ananteris Thorell, 1891, but few details were revealed. Based on observations in the field and laboratory, examination of material in museum collections, and scanning electron microscopy, we document autotomy of the metasoma (the hind part of the opisthosoma, or 'tail') in fourteen species of Ananteris. Autotomy is more common in males than females, and has not been observed in juveniles. When the scorpion is held by the metasoma, it is voluntarily severed at the joints between metasomal segments I and II, II and III, or III and IV, allowing the scorpion to escape. After detachment, the severed metasoma moves (twitches) automatically, much like the severed tail of a lizard or the severed leg of a spider, and reacts to contact, even attempting to sting. The severed surface heals rapidly, scar tissue forming in five days. The lost metasomal segments and telson cannot be regenerated. Autotomy of the metasoma and telson results in permanent loss of the posterior part of the scorpion's digestive system (the anus is situated posteriorly on metasomal segment V) and the ability to inject venom by stinging. After autotomy, scorpions do not defecate and can only capture small prey items. However, males can survive and mate successfully for up to eight months in the laboratory. In spite of diminished predation ability after autotomy, survival allows males to reproduce. Autotomy in Ananteris therefore appears to be an effective, adaptive, anti-predation escape mechanism.
authors: Universidad Nacional de Córdoba, Córdoba, Argentina.
authors: Camilo I
authors: CI
authors: Mattoni
authors: Universidad Industrial de Santander, Bucaramanga, Colombia; Universidade de São Paulo, São Paulo, Brazil.
authors: Solimary
authors: S
authors: García-Hernández
authors: Museo Argentino de Ciencias Naturales "Bernardino Rivadavia", Buenos Aires, Argentina; Pontificia Universidad Javeriana, Bogotá, Colombia.
authors: Ricardo
authors: R
authors: Botero-Trujillo
authors: Frankfurt Zoological Society, Cusco, Perú; Universidade de São Paulo, São Paulo, Brazil.
authors: José A
authors: JA
authors: Ochoa
authors: Museo Argentino de Ciencias Naturales "Bernardino Rivadavia", Buenos Aires, Argentina.
authors: Andrés A
authors: AA
authors: Ojanguren-Affilastro
authors: Universidade de São Paulo, São Paulo, Brazil.
authors: Ricardo
authors: R
authors: Pinto-da-Rocha
authors: American Museum of Natural History, New York, New York, United States of America.
authors: Lorenzo
authors: L
authors: Prendini
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D012605:Scorpions / Q000502:physiology*
references: Biol Rev Camb Philos Soc. 2007 Aug;82(3):481-510
references: 17624964
references: An Acad Bras Cienc. 2013 Apr-Jun;85(2):709-25
references: 23828351
references: Biol Lett. 2010 Feb 23;6(1):70-3
references: 19740891
references: Life Sci. 1968 Mar 15;7(6):257-62
references: 5646378
references: Microsc Res Tech. 2001 Dec 15;55(6):369-96
references: 11782069
references: C R Biol. 2012 Aug;335(8):555-61
references: 22938922
references: Experientia. 1970 Mar 15;26(3):317
references: 5417515