The influence of immune challenges on the mean and variance in reproductive investment: a meta-analysis of the terminal investment hypothesis

BMC Biology

Registered Report

Malgorzata Lagisz¹  Yong Zhi Foo¹  Rose E. O’Dea¹  Shinichi Nakagawa¹ 

[1] Evolution & Ecology Research Centre, School of Biological and Environmental Sciences, University of New South Wales, 2052 NSW, Sydney, Australia;

关键词: Life-history theory;    Phenotypic plasticity;    Fecundity compensation;    Reproduction;    Trade-offs;   

DOI  :  10.1186/s12915-023-01603-4

 received in 2019-05-17, accepted in 2023-04-14,  发布年份 2023

来源: Springer

【 摘 要 】

Finding the optimal balance between survival and reproduction is a central puzzle in life-history theory. The terminal investment hypothesis predicts that when individuals encounter a survival threat that compromises future reproductive potential, they will increase immediate reproductive investment to maximise fitness. Despite decades of research on the terminal investment hypothesis, findings remain mixed. We examined the terminal investment hypothesis with a meta-analysis of studies that measured reproductive investment of multicellular iteroparous animals after a non-lethal immune challenge. We had two main aims. The first was to investigate whether individuals, on average, increase reproductive investment in response to an immune threat, as predicted by the terminal investment hypothesis. We also examined whether such responses vary adaptively on factors associated with the amount of reproductive opportunities left (residual reproductive value) in the individuals, as predicted by the terminal investment hypothesis. The second was to provide a quantitative test of a novel prediction based on the dynamic threshold model: that an immune threat increases between-individual variance in reproductive investment. Our results provided some support for our hypotheses. Older individuals, who are expected to have lower residual reproductive values, showed stronger mean terminal investment response than younger individuals. In terms of variance, individuals showed a divergence in responses, leading to an increase in variance. This increase in variance was especially amplified in longer-living species, which was consistent with our prediction that individuals in longer-living species should respond with greater individual variation due to increased phenotypic plasticity. We find little statistical evidence of publication bias. Together, our results highlight the need for a more nuanced view on the terminal investment hypothesis and a greater focus on the factors that drive individual responses.

【 授权许可】

CC BY   
© The Author(s) 2023

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