Spatial learning in captive and wild-born lizards: heritability and environmental effects

Abstract: Animals raised in captivity go through drastically different life experiences compared with those raised in the wild. The captive environment is usually characterised by highly stable conditions and limited social interactions. Such early developmental environment, alone and interacting with genes, can have long-lasting effects on cognitive performance. By testing pairs of mothers and offspring delicate skinks, Lampropholis delicata, we investigated how being raised in a captive environment shapes spatial learning. Additionally, with this design, we were able to evaluate the additive genetic component and strength of genetic effects in this lizard species. Using a Y-maze task, we compared the spatial learning abilities of wild-caught adult female (mothers) delicate skinks, to their captive-born and raised sexually mature offspring. We found that more mothers completed the task and showed shorter latencies compared with offspring who took longer to complete the maze. The offspring performance did not appear to correlate with their mothers’ performance, indicating little narrow-sense heritability. Furthermore, offspring performance was neither affected nor predicted by their mothers’ performance, indicating a limited overall genetic effect. Our results suggest that early life experiences in a captive environment may have a hindering effect on cognitive performance. Significance statement: How important are environmental effects compared with genetics on the development of learning abilities in non-human animals? Studying mother-offspring skink pairs, we show that wild-born mothers outperformed their captive-born offspring in a spatial learning task. We further show that offspring performance in the task was neither explained nor predicted by their mothers’ performance. We suggest that conditions during early-life stages shape spatial learning more than genetics, and stable captive conditions may have a negative effect on the development of spatial learning.