Non-linear costs of reproduction in a long-lived plant

A trade-off between current reproduction and future performance is a key component of life-history theory, but the shape of this trade-off for any specific fitness component remains elusive. We induced 3-5 levels of reproductive effort (RE) by manipulating fruit set of a long-lived orchid in two populations that differed in the length of the growing season and local climate, and examined survival, size and fecundity the following year. Natural fruit set was 72% higher in the long-season population, but was not associated with a significant survival cost in any population. Survival decreased linearly with experimentally increased RE in the short-season population. In both populations, natural RE incurred growth and fecundity costs, and growth costs increased non-linearly with diminishing costs at high RE. Fecundity costs increased linearly with RE in the long-season population, but non-linearly with diminishing costs at high RE in the other. The results demonstrate that the shape of the ...