Protandry, sexual size dimorphism, and adaptive growth

• The concept of adaptive growth has been highly influential.
• Models of adaptive growth apply to seasonal organisms with protandry.
• Sexual size dimorphism (SSD) is also common in seasonal organisms.
• I consider the relationships between protandry, SSD, and adaptive growth.
• Adaptive growth permits the evolutionary independence of protandry and SSD.

Adaptive growth refers to the strategic adjustment of growth rate by individuals to maximize some component of fitness. The concept of adaptive growth proliferated in the 1990s, in part due to an influential theoretical paper by Peter Abrams and colleagues. In their 1996 paper, Abrams et al. explored the effects of time stress on optimal growth rate, development time, and adult size in seasonal organisms. In this review, I explore how the concept of adaptive growth informs our understanding of protandry (the earlier arrival of males to sites of reproduction than females) and sexual size dimorphism in seasonal organisms. I conclude that growth rate variation is an important mechanism that helps to conserve optimal levels of protandry and sexual size dimorphism in changing environments.