Early-life environment and the potential for cascading maternal effects: an experimental approach.
Final Report Abstract
Mothers can not only influence the development of their offspring via their genes, but also by investing in the quality of their offspring’s environment. While short-term consequences of such ‘maternal effects’ are frequently demonstrated, whether maternal effects still play an important role after the offspring become independent is less well known. Using selection lines of a relatively short-lived bird, the Japanese quail (Coturnix japonica), with exceptionally detailed pedigrees, this project set out to investigate the life-long importance of maternal effects. By combining specific breeding designs, experimental manipulation of incubation temperature and chick rearing diet, and life-long monitoring of offspring performance, this project tested for causal consequences of all major pathways for maternal effects. While embryonic development was slower and hatching success tended to be lower under substandard incubation temperature, incubation temperature had no effect on post-hatching growth, survival to sexual maturity, or age at first reproduction. Moreover, reproduction in adulthood, and its senescence, were independent of the prenatal treatment. Similarly, agespecific adult survival was not affected. Egg size had a strong positive effect on chick size at hatching, but this effect rapidly disappeared and was replaced by genetic and residual effects when chicks started to develop outside the egg. There were also no long-term effects on offspring performance in adulthood. Daughters from large eggs did not start to lay earlier, did not lay more or larger eggs, and did not live longer, when taking their genotype into account. In contrast, a poor quality rearing diet did result in a reduced body size throughout adulthood, but without affecting age-specific reproduction and survival. However, daughters reared with the poor diet did lay smaller eggs. Hence, the developmental environment of a mother did affect her size and subsequently the environment she provided for her offspring during embryonic development. Apart from developmental effects on adult size and subsequent egg size, adult performance was strongly affected by inbreeding, which, in line with evolutionary theory on senescence, became stronger with age for reproduction. Overall, these results suggest that intrinsic, or unavoidable, long-term consequences of poor maternal investment are small. In the wild, however, a size advantage in competition for resources may create positive feedback between the quality of the environment in different life stages, which can even have transgenerational consequences. This could cause long-term maternal effects, despite an individual’s genotype and the quality of the current environment being the most important factors in determining individual performance. Prevention of such long-term effects should thus focus on improvement of the current environment.
Publications
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Experimental extra-pair copulations provide proof of concept for fertility insurance in a socially monogamous bird. Proceedings of the Royal Society B: Biological Sciences, 289.
Vedder, Oscar
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The Effect of Manipulated Prenatal Conditions on Growth, Survival, and Reproduction Throughout the Complete Life Course of a Precocial Bird. Frontiers in Ecology and Evolution, 10.
Vedder, Oscar; Bichet, Coraline & Tschirren, Barbara
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Does inbreeding affect personality? An experimental study in Japanese quail chicks. Oral presentation, Behaviour 2023, Bielefeld, Germany.
Beccardi M., Moiron M., Salmón P., Tschirren B. & Vedder O.
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Rapid decline of prenatal maternal effects with age is independent of postnatal environment in a precocial bird. Evolution, 77(11), 2484-2491.
Vedder, Oscar; Tschirren, Barbara; Postma, Erik & Moiron, Maria
