Mild maternal stress disrupts associative learning and increases aggression in offspring

• Published in: Hormones and behavior 2015-05, Vol.71, p.10-15
• Main Authors: Eaton, L., Edmonds, E.J., Henry, T.B., Snellgrove, D.L., Sloman, K.A.
• Format: Article
• Language: English
• Subjects: Aggression - physiology; Animal behavior; Animals; Association Learning - physiology; Color; Conditioning, Operant - physiology; Cues; Environment; Female; Fish; Guppies; Hormones; Hydrocortisone - metabolism; Individuality; Maternal Behavior - physiology; Maternal effects; Maternal Exposure; Maze Learning - physiology; Mirror-image test; Photic Stimulation; Plus-maze learning; Poecilia - physiology; Reward; Stress; Stress, Psychological - psychology; Viviparity
• ISSN: 0018-506X; 1095-6867
• DOI: 10.1016/j.yhbeh.2015.03.005

Maternal stress has been shown to affect behaviour of offspring in a wide range of animals, but this evidence has come from studies that exposed gestating mothers to acute or severe stressors, such as restraint or exposure to synthetic stress hormones. Here we show that exposure of mothers to even a mild stressor reduces associative learning and increases aggression in offspring. Female guppies were exposed to routine husbandry procedures that produced only a minimal, non-significant, elevation of the stress hormone cortisol. In contrast to controls, offspring from mothers that experienced this mild stress failed to learn to associate a colour cue and food reward, and showed a greater amount of inter-individual variation in behaviour compared with control offspring. This mild stress also resulted in offspring that were more aggressive towards their own mirror image than controls. While it is possible that these results could represent the transmission of beneficial maternal characteristics to offspring born into unpredictable environments, the potential for mild maternal stress to affect offspring performance also has important implications for research into the trans-generational effects of stress. •Mild maternal stress reduced associative learning in juvenile guppies.•Offspring aggression was increased by exposure of mothers to a mild stressor.•Maternal stress produced greater individual variation in offspring behaviour.•Mild maternal stress, such as handling, may alter behaviour of captive bred animals.