Chemical mediation of reciprocal mother-offspring recognition in the Southern Water Skink (Eulamprus heatwolei)

Kin recognition has been demonstrated to play an important role in the social structure of a wide range of animals. Most studies to date have examined parent-offspring recognition only in species that provide offspring with direct parental care, however, there are several advantages to parent-offspring recognition even in the absence of direct parental care. In this study we investigated reciprocal mother-offspring recognition in the Australian scincid lizard Eulamprus heatwolei, a species that does not show direct parental care. We examined whether neonates could discriminate between their mothers and unrelated females, and whether females could discriminate between their offspring and unrelated neonates, via chemical cues, using retreat site selection experiments. We conducted trials when neonates were 1 and 4 weeks old to investigate whether responses are maintained as neonates age. We found that both neonates and mothers could discriminate between related and unrelated individuals when neonates were 1 week old. Mothers were more likely to take refuge under tiles treated with the odours of their own offspring, while neonates spent less time in areas treated with the odours of unrelated females. At 4 weeks of age, mothers no longer exhibited discriminatory behaviour between their offspring and unrelated neonates, while neonates were more likely to associate with the odour of any female over the odourless control. We hypothesize that reciprocal mother-offspring recognition in E. heatwolei reduces interference competition between mothers and their offspring and also may be important in habitat selection and territory establishment.