Laura S Hildesheim1, Øystein H Opedal1,2, W Scott Armbruster3,4, Christophe Pélabon1. 1. Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, NTNU, Trondheim, Norway. 2. Research Centre for Ecological Change, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland. 3. School of Biological Sciences, King Henry Building, King Henry I Street, University of Portsmouth, Portsmouth, UK. 4. Institute of Arctic Biology, University of Alaska, Fairbanks, AK, USA.
Abstract
BACKGROUND AND AIMS: To predict the evolutionary consequences of pollinator declines, we need to understand the evolution of delayed autonomous self-pollination, which is expected to evolve as a mechanism of reproductive assurance when cross-pollination becomes unreliable. This involves estimating the costs of increased levels of selfing as well as those associated with floral senescence. METHODS: We studied the mechanisms and costs of delayed self-pollination in the mixed-mating vine Dalechampia scandens (Euphorbiaceae) by first assessing among-population variation in herkogamy and dichogamy, which together determine the rate and timing of autonomous self-pollination. We then tested whether floral longevity responds plastically to delayed pollination. Finally, we assessed the costs of delayed self-pollination in terms of seed number and size, explicitly separating inbreeding depression from effects of floral senescence. KEY RESULTS: Herkogamy varied extensively, while variation in dichogamy was more limited. Unpollinated blossoms increased their longevity, but seed quantity and quality decreased with increasing delays in pollination, independently of inbreeding depression. CONCLUSIONS: In D. scandens, earlier autonomous selfing is facilitated by reduced herkogamy rather than reduced protogyny, providing reproductive assurance while maintaining the possibility for outcrossing events. Effective early autonomous self-pollination may evolve under reduced cross-pollination reliability in response to costs associated with floral senescence.
BACKGROUND AND AIMS: To predict the evolutionary consequences of pollinator declines, we need to understand the evolution of delayed autonomous self-pollination, which is expected to evolve as a mechanism of reproductive assurance when cross-pollination becomes unreliable. This involves estimating the costs of increased levels of selfing as well as those associated with floral senescence. METHODS: We studied the mechanisms and costs of delayed self-pollination in the mixed-mating vine Dalechampia scandens (Euphorbiaceae) by first assessing among-population variation in herkogamy and dichogamy, which together determine the rate and timing of autonomous self-pollination. We then tested whether floral longevity responds plastically to delayed pollination. Finally, we assessed the costs of delayed self-pollination in terms of seed number and size, explicitly separating inbreeding depression from effects of floral senescence. KEY RESULTS: Herkogamy varied extensively, while variation in dichogamy was more limited. Unpollinated blossoms increased their longevity, but seed quantity and quality decreased with increasing delays in pollination, independently of inbreeding depression. CONCLUSIONS: In D. scandens, earlier autonomous selfing is facilitated by reduced herkogamy rather than reduced protogyny, providing reproductive assurance while maintaining the possibility for outcrossing events. Effective early autonomous self-pollination may evolve under reduced cross-pollination reliability in response to costs associated with floral senescence.
Authors: Christopher G Eckert; Susan Kalisz; Monica A Geber; Risa Sargent; Elizabeth Elle; Pierre-Olivier Cheptou; Carol Goodwillie; Mark O Johnston; John K Kelly; David A Moeller; Emmanuelle Porcher; Richard H Ree; Mario Vallejo-Marín; Alice A Winn Journal: Trends Ecol Evol Date: 2009-08-13 Impact factor: 17.712
Authors: Øystein H Opedal; Geir H Bolstad; Thomas F Hansen; W Scott Armbruster; Christophe Pélabon Journal: Evolution Date: 2017-05-18 Impact factor: 3.694