Europe PMC · 2026-01-29
A new critique argues that 'gain curves' — a long-used theoretical tool in evolutionary biology — are mathematically flawed when applied to whole populations, meaning decades of explanations for why plants and animals allocate resources between male and female reproduction may need to be reconsidered.
Gain curve models assume an external 'bank' of mating opportunities that cannot exist in real populations, making their predictions biologically impossible at the population level.
Models built on fixed gain curves can predict unequal total fitness for male versus female function, an outcome that is impossible given the biology of fertilization (each offspring requires one of each).
Local mating competition and sex-specific dispersal patterns are proposed as more biologically valid alternative explanations for observed patterns like low male investment in self-pollinating hermaphrodites or higher pollen output in wind-pollinated plants.