title: Mild maternal stress disrupts associative learning and increases aggression in offspring.
abstract: 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.
authors.affiliation: Institute of Biomedical and Environmental Health Research, School of Science and Sport, University of the West of Scotland, Paisley, Scotland PA1 2BE, UK. Electronic address: lewis.eaton@uws.ac.uk.
authors.forename: L
authors.initials: L
authors.lastname: Eaton
authors.affiliation: Institute of Biomedical and Environmental Health Research, School of Science and Sport, University of the West of Scotland, Paisley, Scotland PA1 2BE, UK.
authors.forename: E J
authors.initials: EJ
authors.lastname: Edmonds
authors.affiliation: School of Life Sciences, Heriot-Watt University, Edinburgh, Scotland EH14 4AS, UK; Center for Environmental Biotechnology, University of Tennessee, Knoxville, TN 37996, USA; Department of Forestry, Wildlife and Fisheries, University of Tennessee, Knoxville, TN 37996 USA.
authors.forename: T B
authors.initials: TB
authors.lastname: Henry
authors.affiliation: WALTHAM Centre for Pet Nutrition, Freeby Lane, Waltham-on-the-Wolds, LE14 4RT, Leicestershire, UK.
authors.forename: D L
authors.initials: DL
authors.lastname: Snellgrove
authors.affiliation: Institute of Biomedical and Environmental Health Research, School of Science and Sport, University of the West of Scotland, Paisley, Scotland PA1 2BE, UK.
authors.forename: K A
authors.initials: KA
authors.lastname: Sloman
mesh_terms: D000374:Aggression / Q000502:physiology*; D000818:Animals; D001245:Association Learning / Q000502:physiology*; D003116:Color; D003216:Conditioning, Operant / Q000502:physiology; D003463:Cues; D004777:Environment; D005260:Female; D006854:Hydrocortisone / Q000378:metabolism; D007206:Individuality; D008425:Maternal Behavior / Q000502:physiology*; D018811:Maternal Exposure; D018782:Maze Learning / Q000502:physiology; D010775:Photic Stimulation; D011036:Poecilia / Q000502:physiology*; D012201:Reward; D013315:Stress, Psychological / Q000523:psychology*
chemical_list: D006854:Hydrocortisone
keywords: Guppies; Maternal effects; Mirror-image test; Plus-maze learning; Viviparity