Dealing with the unexpected: the effect of environmental variability on behavioural flexibility in a Mediterranean lizard

Abstract

Harsh and variable environments have been hypothesized to both drive and constrain the evolution towards higher cognitive abilities and behavioural flexibility. In this study, we compared the cognitive abilities of island and mainland Aegean wall lizards (Podarcis erhardii), which were expected to live in respectively a more variable and a more stable habitat. We used four proxies of behavioural flexibility: a neophobia assay, a problem-solving test and a spatial + reversal learning task. Surprisingly, the two populations did not differ in neophobia or problem-solving. Insular lizards, however, outperformed mainland conspecifics in an initial spatial learning task, but were less successful during the subsequent reversal learning. Our results thus seem to indicate that the effect of environmental variability on cognition is complex, as it may favour some, but not all aspects of behavioural flexibility.

Bold and bright: shy and supple? The effect of habitat type on personality–cognition covariance in the Aegean wall lizard (Podarcis erhardii)

“…Perhaps lizards from dense habitats, like gobies (White and Brown, 2014), use multiple types of cues to navigate their environment. But then again, the strong side-bias observed in our experiments suggests that lizards from both habitats rely heavily on egocentric cues (discussed in De Meester et al, 2021).…”

“…Neophobia trials followed the same procedure as the training trials, with the exception that a novel object was placed next to the petri dish at the start of each trial. Per trial, we calculated a neophobia score as the relative change in attack latency (%): the attack latency during the neophobia trial minus the control attack latency, divided by the control attack latency (Guido et al, 2017;De Meester et al, 2021). Each lizard was exposed to novel objects twice (either a red toy car or two yellow and orange glow rings, order randomized) generally on two consecutive days.…”

“…removing the lid and grabbing the prey should constitute a single motor sequence). Trials in which the lid fell of due to a lizard dragging it along while moving over or near the dish were considered as accidental openings and discarded, given that lizards often continued to attack the transparent wall of the open dish in such cases, sometimes up to several minutes (De Meester et al, 2021). The time difference between first contact with the dish and grabbing the mealworm was taken as the 'solving time'.…”

“…Trials were scored as successful if the lizard's first choice was the safe refuge, and individuals were considered to have learnt the task if they were successful in five out of six consecutive trials (Vardi et al, 2020) which was previously demonstrated to be a robust criterion for lizards (Noble et al, 2014;De Meester et al, 2021). Two lizards (one simple, one complex) that initially failed the spatial learning were able to reach the 5/6-criterion in the first trial of the reversal, and hence were still classified as learners.…”

Reinstating reptiles: from clueless creatures to esteemed models of cognitive biology

“…It is then tested whether variation in cognitive performance or brain anatomy among these groups can be related to differences in this ecological variable (see review in Henke-von der Malsburg et al, 2020). Likewise, in this special issue De Meester et al (2021) aimed to test two conflicting hypotheses regarding the effect of environmental variability on behavioural flexibility in Aegean wall lizards (Podarcis erhardii). To do so, the authors compared the performance of lizards originating from an island (high environmental variability in resources) and a mainland population (more stable resources) on an array of cognitive tasks (Figure 1C).…”