title: Timing of self-compatibility, flower longevity, and potential for male outcross success in Leptosiphon jepsonii (Polemoniaceae).
abstract: When fertilization triggers flower senescence, early autonomous selfing may cause flowers to senesce before pollen has dispersed, discounting unused pollen. Selfing-induced flower senescence was examined in Leptosiphon jepsonii, a species that varies in the timing of self-compatibility. In field and greenhouse experiments, fertilization had a large effect on flower senescence; most outcrossed flowers senesced after 1 d whereas emasculated flowers lasted 2-5 d. In a comparison of inbred lines from three populations, longevity of autonomously selfed flowers of early self-compatible individuals was significantly less than that of late self-compatible individuals. In field experiments, autonomously selfed flowers were shorter-lived in a predominantly early-selfing population than in a predominantly late-selfing population. Pollen was available and viable beyond the first day of anthesis, suggesting that reductions in flower longevity caused by autonomous selfing could incur a cost to male outcross fitness. We argue that this effect is likely to be most pronounced under intermediate rates of pollinator visitation. Observed pollinator visitation rates ranged from 0.035-0.775 visits per flower per day, indicating a potential for selfing-induced flower senescence to incur pollen discounting in Leptosiphon jepsonii.
authors.affiliation: East Carolina University, Department of Biology, Greenville, North Carolina 27858 USA.
authors.forename: Jennifer J
authors.initials: JJ
authors.lastname: Weber
authors.forename: Carol
authors.initials: C
authors.lastname: Goodwillie