Heat and scarce pollinators together shorten how long flowers stay open
Spigler RB, Ostrowski S.
Pollinators
Watch the wildflowers in a dry August meadow and you're watching evolution in real time: the same flower that would stay open for days in a cool, pollinator-rich summer snaps shut in hours when heat stress and scarce bees collide.
Flowers don't stay open forever, and scientists wanted to know what decides how long they last. It turns out two things work together: once a flower gets enough pollen, it wilts faster on purpose, saving the plant's energy. But if the air is very dry and evaporating a lot of water, flowers also close up early even when pollinators are rare. That timing matters because a flower has to be open at the right moment to get pollinated and make seeds.
Key Findings
Higher pollen deposition rates reduced both the mean and variance of floral longevity, compressing the distribution of flower lifespans across the population.
Vapor pressure deficit (air dryness) independently shortened flower lifespan, with the strongest suppressive effect occurring under low pollination rates where selection would otherwise favor longer-lived flowers.
A flower lifespan-number trade-off and a positive lifespan-size relationship persisted regardless of pollination treatment, indicating these correlations are robust phenotypic constraints.
chevron_right Technical Summary
How long a flower stays open is shaped by both pollination success and weather stress, and these two forces interact. In wild rose-pink (Sabatia angularis), flowers wilted faster when pollinated more, but dry, high-evaporation days also cut longevity short, especially when pollination was scarce.
Abstract Preview
Original paper
Pollination context and abiotic stress reshape variation in floral longevity and its exposure to selection.
Floral longevity is thought to evolve by natural selection imposed by pollinators and resource constraints acting on heritable phenotypic variation. In species with pollination-induced wilting, pol...
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Sabatia angularis, commonly called rosepink, rose pink, square-stem rose pink or rose gentian, is a biennial flowering plant in the Gentianaceae (gentain) family. It is native to central and eastern North America.