Tail Autotomy and Its' Effects on Habitat Selection: An Article Review

Tail tip removal for tissue sampling has no short-term effects on microhabitat selection by Podarcis bocagei, but induced autotomy does.

Acta Herpetologica

Enrique García-Muñoz, Francisco Ceacero, Luis Pedrajas, Antigoni Kaliontzopoulou, Miguel Á. Carretero

     Some species of lizards have the ability to autotomize their tail in the event of a run-in with a predator. Losing their tail greatly increases their chance of survival because their tail acts as a distraction to the predator, giving the lizard time to escape and to find safety away from the predator who was fooled into thinking they had caught a meal. Although tail autotomy has its' benefits, it also has some disadvantages. Having previously lost their tail means they cannot risk being caught by a predator again because they do not have a tail to lose. This absence changes a lizard's habitat preference from uncovered spaces to covered areas. 

http://reptile-database.reptarium.cz/species?genus=Podarcis&species=bocagei

     The species that was studied in this experiment was the Podarcis bocagei that is only found in the northwestern Iberian Peninsula of Europe. Nine adult males, 9 adult females, and 9 juveniles were collected with their tails fully intact. Part one of the experiment was to mark each one as: no manipulation to their tail, full tail autotomized, or removal of a less than 1cm piece of their tail. Part two of the experiment was to observe the type of habitat the individual goes to: totally covered (1), partially covered (2), partially uncovered (3), and totally uncovered (4). 

Table 1. Differences in microhabitat selection before and after tail manipulation

       The results show that individuals who had their tail autotomized were more prone to be observed in totally covered or partially covered habitats. Those that had their tail reduced by less than 1cm or not manipulated at all were more likely to be observed in totally uncovered or partially uncovered habitats. Before and after tail manipulation shows that the individuals that didn't have their tails altered were observed in the same habitat as before. Individuals that had less than 1cm removed either stayed in their "before" habitats or moved to a more covered area. 

     This study demonstrates that habitat preference can change in response to the loss of a lizard's tail. Knowing that they no longer have their tail to lose, lizards will find more covered habitats to live in than open ones where contact with a predator is more likely. Habitats that are more covered enable lizards to be more cryptic, thus allowing them to hide from predators and possible death. 

     I think this experiment is valuable because it gives us insight into possible reproductive declines and locomotion problems. To attract a mate, male and females have to be seen by conspecifics in order to be courted and copulated with. However, the absence of a lizard's tail alters their behavior to seek out more covered habitats, thus hindering potential mates from seeing, courting, and copulating with them. Tails also function as a counterbalance when walking or running. With their tail missing, it makes locomotion difficult, like humans trying to walk/run without their big toe. It is clear that a lizard's tail has both benefits when it's present and disadvantages when it's lost.

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