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Lorenzo Prendini – One of the best experts on this subject based on the ideXlab platform.
scorpion sheds tail to escape consequences and implications of Autotomy in scorpions buthidae ananterisPLOS ONE, 2015Co-Authors: Camilo I Mattoni, Solimary Garciahernandez, Ricardo Boterotrujillo, Jose A Ochoa, Andres A Ojangurenaffilastro, Ricardo Pintodarocha, Lorenzo PrendiniAbstract:
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.
Panayiotis Pafilis – One of the best experts on this subject based on the ideXlab platform.
Insights into how predator diversity, population density and habitat type may affect defensive behaviour in a Mediterranean lizard, 2018Co-Authors: Pantelis Savvides, Venetia Poliviou, Maria Stavrou, Spyros Sfenthourakis, Panayiotis PafilisAbstract:
Various factors may alter anti-predatory responses among conspecifics. Here we assess some of these factors using three populations of a Mediterranean lizard (Acanthodactylus schreiberi) in Cyprus that differ in their habitat type, predator diversity and population density. We expected that predation would affect flight initiation distance (FID; the approach distance allowed to an observer before the lizard flees), escape distance (ED; the distance covered by the lizard from the point an escape attempt starts to the first place the lizard stops) and tail Autotomy (Autotomy rates, economy of Autotomy, post-Autotomy tail movement). We also predicted that juveniles, being more exposed to predators, would be more effective in their defensive responses. Our findings suggest that predation and population density appear to be associated with most Autotomy traits but were not associated with FID and ED, which are better explained by refuge availability. The only ontogenetic difference was detected in the economy of Autotomy: juveniles are more prone to autotomise, possibly because they do not experience such high costs as tailless adult individuals. Our results suggest that anti-predatory responses are influenced by a variety of factors. Unravelling the compound effects of all the factors involved should be the focus of future research.
Sex does not affect tail Autotomy in lacertid lizardsActa Herpetologica, 2017Co-Authors: Panayiotis Pafilis, Kostas Sagonas, Grigoris Kapsalas, Johannes Foufopoulos, Efstratios D. ValakosAbstract:
Caudal Autotomy is one of the most effective and widespread defensive mechanisms among lizards. When predators grasp the tail, lizards are able to shed it from the point of the attack and further. Numerous factors have been reported to affect tail-shedding performance such as temperature, age, predation pressure, intraspecific competition etc. Interestingly, the impact of sex on tail loss remains greatly understudied. Here, we analyzed tail Autotomy performance, simulated in the lab, in 12 species of lacertid lizards belonging to five genera ( Algyroides , Anatololacerta , Hellenolacerta , Ophisops , Podarcis ). Our aim was to investigate whether sex affects caudal Autotomy and/or the duration of post-autotomic tail movement. We failed to detect any effect of sex on tail loss in the species examined. Also, we did not find any sexual impact on the duration of tail movement after Autotomy, with a single exception. Our findings suggest that Autotomy serves as a defensive tactic equally in both sexes and is used in the same extent.
intraspecific competition not predation drives lizard tail loss on islandsJournal of Animal Ecology, 2017Co-Authors: Yuval Itescu, Rachel Schwarz, Shai Meiri, Panayiotis PafilisAbstract:
Tail Autotomy is mainly considered an antipredator mechanism. Theory suggests that predation pressure relaxes on islands, subsequently reducing Autotomy rates.
Intraspecific aggression, which may also cause tail loss, probably intensifies on islands due to the higher abundance.
We studied whether tail Autotomy is mostly affected by predation pressure or by intraspecific competition. We further studied whether predator abundance or predator richness is more important in this context.
To test our predictions, we examined multiple populations of two gecko species: Kotschy’s gecko (Mediodactylus kotschyi; mainland and 41 islands) and the Mediterranean house gecko (Hemidactylus turcicus; mainland and 17 islands), and estimated their abundance together with five indices of predation.
In both species, Autotomy rates are higher on islands and decline with most predation indices, in contrast with common wisdom, and increase with gecko abundance. In M. kotschyi, tail-loss rates are higher on predator and viper-free islands, but increase with viper abundance.
We suggest that Autotomy is not simply, or maybe even mainly, an antipredatory mechanism. Rather, such defence mechanisms are a response to complex direct and indirect biotic interactions and perhaps, in the case of tail Autotomy in insular populations, chiefly to intraspecific aggression.
Sylvie Biagiantirisbourg – One of the best experts on this subject based on the ideXlab platform.
toxic effects and bioaccumulation of the herbicide isoproturon in tubifex tubifex oligocheate tubificidae a study of significance of Autotomy and its utility as a biomarkerAquatic Toxicology, 2010Co-Authors: Severine Parispalacios, Yahia Y Mosleh, Mohamad Almohamad, Laurence Delahaut, Arnaud Conrad, Fabrice Arnoult, Sylvie BiagiantirisbourgAbstract:
Tubifex is the only animal reported to respond with Autotomy to contamination. This response of contaminated worm is understood as a mode of metal excretion. Few data concern the potential of organic compounds to induce tubifex Autotomy. The objective of this study was to investigate if Autotomy can be induced by a herbicide isoproturon (IP) and be related to the way of excretion. Isoproturon accumulation in worm tissues and its effect on tubifex mortality, Autotomy and regeneration rates were analysed after 4 and 7 days of exposure to the herbicide and also when worms were replaced for 10 days in clean water. IP accumulated in the same way in all parts of the worm body but IP metabolite rates were significantly higher in the posterior part of the worm. Thus the loss of the posterior part allows the worm to eliminate an important amount of pesticide. Autotomy has a population importance and is related to the degree of worm contamination so it may become an interesting biomarker.