Scale dependence of sex ratio in wild plant populations: implications for social selection

Abstract

Social context refers to the composition of an individual's social interactants, including potential mates. In spatially structured populations, social context can vary among individuals within populations, generating the opportunity for social selection to drive differences in fitness functions among individuals at a fine spatial scale. In sexually polymorphic plants, the local sex ratio varies at a fine scale and thus has the potential to generate this opportunity. We measured the spatial distribution of two wild populations of the gynodioecious plant Silene vulgaris and show that there is fine‐scale heterogeneity in the local distribution of the sexes within these populations. We demonstrate that the largest variance in sex ratio is among nearest neighbors. This variance is greatly reduced as the spatial scale of social interactions increases. These patterns suggest the sex of neighbors has the potential to generate fine‐scale differences in selection differentials among individuals. One of the most important determinants of social interactions in plants is the behavior of pollinators. These results suggest that the potential for selection arising from sex ratio will be greatest when pollen is shared among nearest neighbors. Future studies incorporating the movement of pollinators may reveal whether and how this fine‐scale variance in sex ratio affects the fitness of individuals in these populations.

Homologous recombination changes the context of Cytochrome b transcription in the mitochondrial genome of Silene vulgaris KRA

“…S. vulgaris has been investigated in multiple population genetic studies [ 41 – 44 ], but a detailed understanding of the evolutionary processes responsible for its extremely rearranged and diverse mt genomes [ 9 ] is still lacking. The comprehensive transcriptomic study of the mt haplotype KOV of S. vulgaris lacking chimeric ORFs revealed a mt long non-coding RNA associated with CMS [ 45 ].…”

Non-coding RNA may be associated with cytoplasmic male sterility in Silene vulgaris

“…Olson and McCauley, 2002; Štorchová and Olson, 2004; Sanderson et al , 2016). An unprecedented level of intraspecific diversity has been revealed in the complete mt genome sequences of four haplotypes of this species (Sloan et al , 2012 b ).…”

“…One of the most thoroughly explored examples of CMS in natural populations is in bladder campion ( Silene vulgaris ), a model system for the investigation of gynodioecy ( Bernasconi et al , 2009 ), used in numerous population genetic studies (e.g. Olson and McCauley, 2002 ; Štorchová and Olson, 2004 ; Sanderson et al , 2016 ). An unprecedented level of intraspecific diversity has been revealed in the complete mt genome sequences of four haplotypes of this species ( Sloan et al , 2012 b ).…”

Sexual selection and sex ratios in Anolis lizards

“…If such changes in sex ratio are persistent across multiple generations in their bias toward a single sex, they can lead to alterations in patterns of sexual selection within a population, modifying the intensity of both inter‐sexual and intra‐sexual selection. This phenomenon of increased sexual selection due to sex ratio bias has been observed across multiple taxa in both natural populations and experimental manipulations: within‐sex competition and mate selection strategies respond to changes in sex ratio skew in plants (Sanderson et al ., ), insects (Linklater et al ., ), amphibians (Pröhl, ; Jones, Arguello & Arnold, ), fish (Grant, Bryant & Soos, ; Mills & Reynolds, ), birds (Pruett‐Jones & Lewis, ) and mammals (Mitani, Gros‐Louis & Richards, ). Studying the causes and consequences of biased sex ratios may therefore uncover a framework for the evolution of mating systems, and by extension, reflect the strength of sexual selection in different species (Emlen & Oring, ; Pipoly et al ., ).…”