Pollination elicits an accelerated reduction in nocturnal scent emission by flowers of the dioecious herb Silene latifolia

Abstract

More than 85% of plants rely on biotic pollen vectors attracted by olfactory or visual signals. While these signals are beneficial for plant reproduction, they are also costly in terms of resource investment, and may involve additional costs related to herbivore attraction, transmission of diseases, and increased transfer of self-pollen among flowers of an individual plant. Given the potential costs of signalling to pollinators, we hypothesized that plants should cease signalling to pollinators as soon as the costs of being attractive exceed the benefits. Here, we used the herb Silene latifolia Poir., which is pollinated by the nocturnal seed-predator Hadena bicruris, to investigate the possible reduction of scent emission after pollination. We compared the progressive decrease of scent and attractive compound emission between pollinated and unpollinated flowers on an hourly basis, overnight. We found that total scent emission decreased significantly faster over time for pollinated than for non-pollinated flowers. Our findings suggest that the costs of maintaining the attractiveness of pollinated flowers of Silene latifolia exceed the benefits, which could be linked with the risks of parasitism.