title: Fear is the mother of invention: anuran embryos exposed to predator cues alter life-history traits, post-hatching behaviour and neuronal activity patterns.
abstract: Neurophysiological modifications associated to phenotypic plasticity in response to predators are largely unexplored, and there is a gap of knowledge on how the information encoded in predator cues is processed by prey sensory systems. To explore these issues, we exposed Rana dalmatina embryos to dragonfly chemical cues (kairomones) up to hatching. At different times after hatching (up to 40 days), we recorded morphology and anti-predator behaviour of tadpoles from control and kairomone-treated embryo groups as well as their neural olfactory responses, by recording the activity of their mitral neurons before and after exposure to a kairomone solution. Treated embryos hatched later and hatchlings were smaller than control siblings. In addition, the tadpoles from the treated group showed a stronger anti-predator response than controls at 10 days (but not at 30 days) post-hatching, though the intensity of the contextual response to the kairomone stimulus did not differ between the two groups. Baseline neuronal activity at 30 days post-hatching, as assessed by the frequency of spontaneous excitatory postsynaptic events and by the firing rate of mitral cells, was higher among tadpoles from the treated versus the control embryo groups. At the same time, neuronal activity showed a stronger increase among tadpoles from the treated versus the control group after a local kairomone perfusion. Hence, a different contextual plasticity between treatments at the neuronal level was not mirrored by the anti-predator behavioural response. In conclusion, our experiments demonstrate ontogenetic plasticity in tadpole neuronal activity after embryonic exposure to predator cues, corroborating the evidence that early-life experience contributes to shaping the phenotype at later life stages.
authors.affiliation: Dipartimento di Scienze della Terra e dell'Ambiente, Laboratorio di Eco-Etologia, Università di Pavia, Via Ferrata 9, Pavia 27100, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Gazzola
authors.affiliation: Dipartimento di Biologia e Biotecnologie, Laboratorio di Fisiologia, Università di Pavia, Via Ferrata 9, Pavia 27100, Italy Brain Research Institute, University of Zurich, Winterthurerstrasse 190, Zurich, CH 8057, Switzerland.
authors.forename: Federico
authors.initials: F
authors.lastname: Brandalise
authors.affiliation: Dipartimento di Bioscienze, Università di Milano, Via Celoria 26, Milano 20133, Italy.
authors.forename: Diego
authors.initials: D
authors.lastname: Rubolini
authors.affiliation: Dipartimento di Biologia e Biotecnologie, Laboratorio di Fisiologia, Università di Pavia, Via Ferrata 9, Pavia 27100, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Rossi
authors.affiliation: Dipartimento di Scienze della Terra e dell'Ambiente, Laboratorio di Eco-Etologia, Università di Pavia, Via Ferrata 9, Pavia 27100, Italy galeozot@unipv.it.
authors.forename: Paolo
authors.initials: P
authors.lastname: Galeotti
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D003463:Cues; D019706:Excitatory Postsynaptic Potentials; D005239:Fear / Q000502:physiology*; D007814:Larva / Q000737:chemistry / Q000502:physiology; D008018:Life Cycle Stages; D063191:Odonata / Q000737:chemistry*; D009812:Odorants; D011235:Predatory Behavior; D011898:Ranidae / Q000196:embryology / Q000254:growth & development / Q000502:physiology*; D012903:Smell
keywords: Behavioural plasticity; Defensive behaviour; Kairomone; Mitral neurons; Neuronal plasticity; Olfactory sensory system; Phenotypic plasticity