DOI: 10.25338/b80k70
title: Impacts of caudal autotomy on personality

description: Caudal autotomy, the voluntary shedding of a tail, is a last-ditch
 strategy used by many lizard species to escape from predators. There are
 several costs associated with caudal autotomy that may cause lizards to
 make behavioral adjustments during tail regeneration. These behavioral
 changes may be dependent upon individual differences in response to
 autotomy (e.g. trait or state-dependent differences) and/or the degree of
 tail loss, as many lizards have the capacity to only partially shed their
 tail which likely entails fewer costs relative to complete autotomy.
 However, no study, to our knowledge, has considered how caudal autotomy,
 or the extent of autotomy, affects individual behavioural variation.
 Accordingly, we investigated the effects of both partial and complete tail
 loss on individual behavioural variation in delicate skinks, Lampropholis
 delicata. We found that lizards which experienced complete tail loss, on
 average, became less active, explorative and had much slower sprint speeds
 following autotomy. These lizards also became more predictable and
 consistent in their behaviour post-autotomy, exhibiting a notable decrease
 in their within-individual behavioural variance. In contrast, we did not
 see any significant behavioural effects in lizards which experienced
 partial tail loss. We also found a positive among-individual correlation
 between activity/exploration and neophilia, but tail loss had no effect on
 the structure of this syndrome. Our results suggest that complete tail
 loss may impose effects on traits more closely associated with locomotion
 and predator escape ability, whilst also constraining an individual’s
 capacity for differential behavioural expression.
description: Skinks were randomly assigned to one of three treatment groups:
 no tail loss (i.e. control, n = 18), partial tail loss (n = 19) and
 complete tail loss (n = 19). Before tail loss treatments were applied, we
 first tested each individual through a series of behavioural assays to
 examine variation and correlation amongst four traits:
 activity/exploration, sociability, neophilia and sprint speed. To assess
 behavioural repeatability, we tested individuals in each behavioural assay
 twice, with each re-test occurring one-week apart to examine short-term
 repeatability. Once the pre-treatment assays were completed, skinks in the
 ‘partial’ and ‘complete’ tail loss groups underwent intravertebral tail
 autotomy. Specifically, caudal autotomy was stimulated by pinching the
 tail with fine forceps (<i>sensu</i> Cromie & Chapple
 2012). Complete tail loss equated to the removal of a full tail, where
 lizards had their tails removed at approximately 10 mm posterior to the
 base of the tail. Partial tail loss involved skinks experiencing a break
 half-way (~ 5 mm from the tip of the tail) along the length of the tail
 from the tail’s base. Control lizards retained their full-length tail but
 experienced a similar handling procedure to control for potential
 behavioural changes brought about by handling stress alone. One week after
 the tail loss treatment was applied, skinks were again tested twice for
 each behavioural assay. 
description: CSV file headings SKINK_ID - individual
 ID TREATMENT - Tail loss treatment
 TAIL_LOSS - Did a lizard experience any type of tail loss (Yes or
 No) STAGE - Before or after treatment
 SVL - Body length TRIAL - Trial number (2
 repeats per stage) ACTIVITY - Number of grid
 transitions made in a non-directed activity test SOCIAL
 - Time spent basking with conspecifics FORAGING - Time
 spent near a novel food item BURST_SPEED - maximal
 sprint speed AVERAGE_SPEED - average speed over trial
 runs (I.e. within each trial, a lizard was raced down a track 2
 times) TIME_IN_OPEN - proportion of time a lizard spent
 in the open (I.e. not in shelter, after a simulated predatory
 attack TIME_IN_REFUGE - proportion of time a lizard
 spent in refuge after a predatory attack.