Evolution of Reproductive Plasticity in a Seasonal Tropical Environment

Seasonality can drive the evolution of reproductive plasticity in insects. An extreme form is reproductive diapause, where individuals halt reproduction during unfavourable seasons. How diapause evolves from milder forms of plasticity (e.g., through changes in cue perception and responses) is poorly understood. In the tropics, seasonality is common, but it is unclear how widespread reproductive plasticity is, or how it correlates with dry and wet seasons. Here, we analyse reproductive plasticity in Amazonian butterflies using a four-year monthly time series of reproductive phenotypes. Sampling nine species across four Nymphalidae subfamilies, we observe a widespread occurrence of diverse reproductive plasticity, suggesting repeated evolutionary changes in reproductive plasticity. Detailed analyses of two Catonephele species reveal a conserved cue (temperature), with species-specific divergence of cue response (dry season diapause only in C. acontius). Together, our data support the ubiquity of reproductive plasticity in the tropics and suggest repeated evolutionary change in diapause.