Abstract Detail

Reproductive Processes

Ostrowski, Susanna [1], Spigler, Rachel [1].

Plasticity of floral longevity in Sabatia angularis (Gentianaceae): tracking the optimum under different pollination rates.

Floral longevity, the amount of time that a flower remains open and functional, is a critical component of reproductive success, determining the window of opportunity for pollen export and receipt. Surprisingly, though, research on the forces shaping the evolution of floral longevity is scant compared to other attractive floral traits. Theoretical models rooted in resource allocation theory predict that a species’ optimal floral longevity will be influenced by the rates at which pollen is deposited (female fitness accrual) and removed (male fitness accrual) from a plant balanced by the costs of floral maintenance. We applied this theory to variation within species and asked how fitness gain curves and floral costs may shape plasticity of floral longevity in the biennial Sabatia angularis (Gentianaceae). In a wild population, we experimentally manipulated pollinator visitation rates to S. angularis individuals. We then quantified floral longevity and pollen deposition and removal rates for plants under ambient versus depressed pollinator visitation rates. We found that both male and female fitness show a saturating function with respect to floral age, with male fitness accruing at a faster rate than female fitness in this protandrous species. Female fitness accrual rates were slowed in plants with reduced visitation. However, these plants had significantly greater floral longevity resulting in similar total amounts of pollen deposition by the end of floral lifespan. Together with experimentally derived estimates of the cost of longevity, our results highlight how plasticity of floral longevity may allow plants to optimize fitness at the level of individual flowers, with implications for the ability of plants to compensate for lower rates of pollen receipt under global pollinator declines. 

1 - Temple University, Biology, 1900 N 12th Street, Philadelphia, PA, 19122, USA

floral longevity
fitness gain curves
floral costs
plant reproduction
pollination biology
resource allocation.

Presentation Type: Oral Paper
Session: REP4, Reproductive Processes 4
Location: Virtual/Virtual
Date: Thursday, July 30th, 2020
Time: 3:30 PM
Number: REP4003
Abstract ID:638
Candidate for Awards:None

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