Reproducing under a warming climate: long winter flowering and extended flower longevity in the only Mediterranean and maritime Primula

Under the pressure of global warming, general expectations of species migration andevolution of adaptive traits should always be confirmed with species-specific studies.Within this framework, some species can be used as study systems to predict possibleconsequences of global warming also on other relatives. Unlike its mountain congeneric,Primula palinuri Petagn. has endured all the climatic fluctuations since thePleistocene, while surviving on Mediterranean coastal cliffs. The aim of this work wasto investigate the possible evolution of reproductive biological and ecological traits inP. palinuri adaptation to a warmer environment. Data showed that flowering starts inmid-winter; single flowers remain open for over a month, changing from pendulousto erect. The number of insects visiting flowers of P. palinuri increases during theflowering season, and pollination reduces flower longevity. Overall, the best pollenperformances, in terms of viability and germinability, occur at winter temperatures,while pollinator activity prolongs flowering until spring. Moreover, extended longevityof single flowers optimises reproductive success. Both phenotypic plasticity andselective processes might have occurred in P. palinuri. However, we found that reproductivetraits of the only Mediterranean Primula remain more associated with coldmountain habitats than warm coastal cliffs. Given the rapid trend of climate warming,migration and new adaptive processes in P. palinuri are unlikely. Response to past climatewarming of P. palinuri provides useful indications for future scenarios in otherPrimula species.