How to stay alive after losing your tail

Abstract

Prey that autotomize appendages to escape predation may suffer reduced escape speed and be unable to autotomize lost parts, rendering them more vulnerable. Little is known about behavioural compensation for increased risk by altering decisions about fleeing and entering refuges. Flight initiation distance (FID) is distance between prey and an approaching predator when the prey begins to flee. Escape theory predicts that FID increases with predation risk, but FID decreased after autotomy in the lizard Scincella lateralis, which compensated by becoming more cryptic via reduced mobility. We tested the hypotheses that in a lizard that does not decrease surface activity, stay closer to refuge, or shift to crypsis after autotomy associated with reduced speed, behavioural compensation occurs by increasing FID, distance fled and probability of entering refuge. Running speed in the striped plateau lizard Sceloporus virgatus decreased by 43%, suggesting that selection should favor compensation. Lizards altered escape behaviour after autotomy by increasing FID and refuge use, but did not increase distance fled. To predict effects of autotomy on FID and distance fled, the nature of qualitative compensatory changes must be known. Factors likely to affect which compensatory mechanisms are used include foraging mode and refuge availability.