Variation in floral longevity in the genus Leptosiphon: mating system consequences

Abstract

Pollination or fertilisation trigger floral senescence in a wide range of flowering plants, and yet little attention has been given to the implications of this phenomenon to mating system evolution. We examined the effects of pollination on floral senescence in the genus Leptosiphon. Species in the genus exhibit a wide range of breeding systems. In all cases, compatible pollination induced senescence; emasculated flowers lived longer than hand-outcrossed flowers. In the self-compatible species, Leptosiphon acicularis and L. bicolor, and in one highly selfing population of L. jepsonii, unmanipulated flowers had reduced longevity compared to emasculated flowers, suggesting that autonomous self-pollination limits floral longevity in these species. Limited floral longevity in these highly selfing taxa may reduce opportunities for male outcross success, representing a possible source of selection on the mating system. In turn, the mating system might influence how selection acts on floral longevity; obligately outcrossing taxa are expected to benefit from longer floral longevities to maximise opportunities for pollination, while selfing taxa might benefit from earlier floral senescence to reduce resource expenditure. Overall, the longevity of unpollinated flowers increased with the level of outcrossing in the genus Leptosiphon. Our results taken together with those of a previous study and similar results in other species suggest that floral longevity may represent a largely unexamined role in mating system evolution.

Context‐dependency of resource allocation trade‐offs highlights constraints to the evolution of floral longevity in a monocarpic herb

“…Floral longevity varies markedly across species, lasting from a single day up to weeks (Primack, ; Stratton, ; Ashman & Schoen, ; Steinacher & Wagner, ). Consistent with predictions related to fitness gains, longevity also varies across species in relation to pollination conditions and to mating system, with those experiencing high pollen limitation having greater mean floral lifespans (Ashman & Schoen, ; Rathcke, ) and reduced floral lifespans in selfing compared to outcrossing species (Weber & Goodwillie, ). However, our understanding of the microevolutionary process that lead to such differences among species is hampered by a lack of empirical data on what generates variation in floral longevity within species and on the trade‐offs that may constrain its evolution.…”

Floral Mass per Area and Water Maintenance Traits Are Correlated with Floral Longevity in Paphiopedilum (Orchidaceae)

“…However, a trade-off may exist between the benefit of increased pollination success and the cost of floral maintenance (Rathcke, 2003). Researchers have suggest that FL is affected by many biotic (Rathcke, 2003; Giblin, 2005; Weber and Goodwillie, 2012) and abiotic factors (Vespirini and Pacini, 2005; Arroyo et al, 2013; Jorgensen and Arathi, 2013). For example, longer flower life spans might be associated with less frequent pollination (Giblin, 2005; Weber and Goodwillie, 2012).…”

“…Researchers have suggest that FL is affected by many biotic (Rathcke, 2003; Giblin, 2005; Weber and Goodwillie, 2012) and abiotic factors (Vespirini and Pacini, 2005; Arroyo et al, 2013; Jorgensen and Arathi, 2013). For example, longer flower life spans might be associated with less frequent pollination (Giblin, 2005; Weber and Goodwillie, 2012). Longevity is also improved in plants growing at higher elevations or lower temperatures, or in areas where soil moisture is high (Vespirini and Pacini, 2005; Arroyo et al, 2013; Jorgensen and Arathi, 2013).…”

Divergence in pollen performance between Clarkia sister species with contrasting mating systems supports predictions of sexual selection

“…First, due to their higher heterozygosity, individuals of outcrossing taxa typically produce pollen that is more genetically diverse than that of highly selfing taxa; consequently, the stigmas of outcrossers receive pollen of higher diversity than those of closely related selfers even when receiving pollen from a single donor. Second, flowers adapted for outcrossing typically stay fresher and receptive longer than those of self-pollinating taxa (Primack 1985;Weber and Goodwillie 2013). This greater longevity can promote multiple pollinator visits and the receipt of pollen from multiple donors, as evidenced by studies showing that seeds within individual fruits often represent multiple fathers (Ellstrand and Marshall 1986;Bernasconi 2003;Mitchell et al 2005;Teixeira and Bernasconi 2007).…”