Larval life history and anti-predator strategies are affected by breeding phenology in an amphibian

• Published in: Oecologia 2013-04, Vol.171 (4), p.873-881
• Main Authors: Orizaola, Germán, Dahl, Emma, Nicieza, Alfredo G., Laurila, Anssi
• Format: Article
• Language: English
• Subjects: Aeshna; Amphibia. Reptilia; Amphibians; Analysis of Variance; Animal and plant ecology; Animal breeding; Animal, plant and microbial ecology; Animals; anti-predator defences; Biological and medical sciences; Biomedical and Life Sciences; Breeding; Breeding time; Climate; Ecological life histories; Ecology; Frogs; Fundamental and applied biological sciences. Psychology; General aspects; Hydrology/Water Resources; Insecta - physiology; Larva - physiology; Larvae; Larval development; Life history; Life Sciences; Metamorphosis; Metamorphosis, Biological - physiology; Motor Activity - physiology; Observation; Odonata; Offspring; Phenology; Phenotypic plasticity; Plant Sciences; POPULATION ECOLOGY; Population ecology - Original research; Predation; Predators; Predatory Behavior - physiology; Rana temporaria; Rana temporaria - physiology; Seasons; Sexual Behavior, Animal - physiology; Sweden; Tadpoles; Time Factors; Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution
• ISSN: 0029-8549; 1432-1939; 1432-1939
• DOI: 10.1007/s00442-012-2456-z

Seasonal time constraints can pose strong selection on life histories. Time-constrained animals should prioritise fast development over predation risk to avoid unfavourable growing conditions. However, changes in phenology could alter the balance between anti-predator and developmental needs. We studied variation of anti-predator strategies in common frog (Rana temporaria) tadpoles in four populations from the two extremes of a latitudinal gradient across Sweden. We examined, under common conditions in the laboratory, the anti-predator responses and life histories of tadpoles raised with predatory Aeshna dragonfly larvae in two consecutive years with a difference of 20 days in breeding time in the north, but no difference in breeding time in the nouth. In a year with late breeding, northern tadpoles did not modify their behaviour and morphology in the presence of predators, and metamorphosed faster and smaller than tadpoles born in a year with early breeding. In the year with early breeding, northern tadpoles showed a completely different anti-predator strategy by reducing activity and developing morphological defences in the presence of predators. We discuss the possible mechanisms that could activate these responses (likely a form of environmentally-mediated parental effect). To our knowledge, this is the first study to show that a vertebrate modifies the anti-predator strategy of its offspring in response to natural variation in reproductive phenology, which highlights the need to consider phenology in studies of life-history evolution.