There are many organisms such as spiders, lizards, and even starfishes (and many more) who voluntarily shed or detach a body part, also known as autotomy. They do so for several reasons. For example, autotomy is an escape strategy (for instance, if a leg is trapped between two rocks). It can also be a distraction for predators — an amputated tail wriggles, and makes a predator look one way while the tail shedder runs the other. Sometimes organisms self-amputate wounded limbs.
In a nutshell, autotomy enhances survival. However, it may also impose some costs.
Recently, scientists tested if this survival strategy incurs any reproductive costs in a scorpion species, Ananteris balzani. The scorpion sheds its tail permanently, causing the loss of the anus and a lifelong inability to poop. Male scorpions also use their tails during mating.
However, the researchers showed that tail loss has no effect on male mating success when compared to males with a tail. Remarkably, a tail-less female had less of babies than females with tails. This interesting finding suggests that the negative effect of “taillessness” is sex-dependent, and in these scorpions it is the females that pay the cost.