Extended flowering in a Mediterranean shrub: Seasonal variability in seed quality and quantity

Fluctuating conditions throughout the year and changes in floral display may promote shifts in pollinator activity and predator pressure, influencing female reproductive output, especially for extended flowering species under seasonal climates. In this regard, flowering and fruit production were tracked in 2 different years in 2 populations of Ononis tridentata in Central Spain. Total fruit production was estimated, and fruits were harvested to obtain primary fruit investment, pollination success, predation incidence, seed production, seed weight and germination rates. Ononis tridentata combined spring mass flowering with a steady long flowering period across the summer and fall. The fewer flowers that are produced in fall were successfully pollinated, and produced fruits that were subject to minimal predation pressure relative to spring fruits. Moreover, fall fruits contained a higher number of heavier seeds and showed higher germination rates than those of spring seeds. Fall reproductive output represent 10% of annual viable seeds and thus may act as an important complement to the main spring reproductive investment. Extended flowering could be interpreted as a “bet-hedging strategy” for enduring Mediterranean unpredictable and changing environmental conditions.