Variation in Pollination: Causes and Consequences for Plant Reproduction

Abstract

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Intraspecific trait variation across scales: implications for understanding global change responses

“…Specifically, if the relationship y = f(x) is concave up, then E[y] > f(E[x]), and if it is concave down (convex), then E[y] < f(E[x]). To give an example, seeds produced per unit pollen declines with increasing pollen deposition; when pollen deposition varies, the average seeds per flower is lower than predicted based on the average pollen deposited per flower (Richards et al, 2009). Similarly, genetic variation in host insects that leads to variation in number of eggs per seed can stabilize host-parasitoid population dynamics via Jensen's inequality (Imura et al, 2003).…”

The population ecology of male gametophytes: the link between pollination and seed production

“…Beta-binomial variation of the type observed for both Parkinsonia and Tristerix would aggravate both problems. Richards et al (2009) referred to such depression of realised reproductive success compared to the expectation based on average pollen receipt as variance limitation. The consequences of within-plant variation in pollen-tube success should select for diverse traits that either reduce the variation or mitigate its effects (see Richards et al 2009;Schreiber et al 2015).…”

Benefit and cost curves for typical pollination mutualisms

“…Visit number and exposure time are likely to be correlated, but not necessarily perfectly, and visitor-imposed benefits and costs to both female and male reproductive success are more likely to be related to the number of visits than to exposure time per se (although the value of a visit may depend on when in a flower's lifetime it occurs should stigma receptivity or pollen viability change as flowers age). Moreover, when the number of visits varies among flowers and the success curve has a negative second derivative over the range of visits, the realized average per flower success will be lower than the height of the curve at the average number of visits (via Jensen's inequality; Richards et al 2009). Thus variation in visit number among a plant's flowers, even if all flowers remain open for the same length of time, can influence whole-plant reproductive success.…”