Large flowers tend to be short-lived in Mediterranean ecosystems: Insights from three Cistus species

Larger and longer lived flowers receive more pollinators, but may also involve increased water maintenance costs under hot, dry environments. Hence, smaller and/or short-lived flowers may buffer such costs. We surveyed floral longevity in three large-flowered Mediterranean Cistus species. We hypothesize that: (1) in Cistus, floral longevity decreases with increasing air temperature and flower size; (2) in C. ladanifer, flower size and longevity increase along an altitudinal gradient; (3) floral longevity is differentially affected by temperature rather than flower size along the gradient; (4) under similar temperature, floral longevity decreases with flower size. For each species, we evaluated the effects of flower size and air temperature on floral longevity. Specifically, floral longevity was surveyed along an altitudinal gradient in the largest flowered species Cistusladanifer. Floral longevity in Cistus species lasted < 1 d and was affected by air temperature, independently of flower size. In C. ladanifer, flower size increased along the gradient but floral longevity decreased. Still, floral longevity decreased with increasing air temperature and, to a lesser extent, with flower size. Together, our findings show a triangular relationship among air temperature, flower size and floral longevity with margins for plasticity to accommodate pollinator attraction with the costs of large-flowered Mediterranean plants.