Effects of crossing distance on fitness components in the carnivorous plant Pinguicula moranensis (Lentibulariaceae)

Abstract

Plant species vary in the pollination distance at which negative fitness effects are expressed, and it has been proposed that optimal mating should occur at a distance large enough to diminish the risks of inbreeding, but short enough to prevent outbreeding depression. In a natural population of Pinguicula moranensis we assessed the fitness of plants (seeds per fruit) and their progeny (germination and seedling survival) as a function of pollination distance by handpollinating with donors from five distances: 0 m (self-fertilization), 1, 4 and 460 m (within-population) and 9,900 m (between-population) under in situ and ex situ conditions. We found that average values for fitness components were consistently lower in the in situ experiment than in the ex situ experiment. Under both conditions, the self-fertilization treatment had the lowest values. Inbreeding depression values were high (0.94 to 0.98), corresponding with the values expected for an outcrossing species subjected to self-fertilization. Overall, no evidence of outbreeding depression was detected. Considering that our experiment was restricted to one single donor population and one recipient population, our results indicate that despite the within-population patchy distribution of individuals, biparental inbreeding could occur at low rates, due in part to short seed dispersal distance. However, pollen movement of at least 1 m is apparently sufficient to reverse negative effects. K E Y W O R D Sex situ experiment, in situ experiment, inbreeding depression, optimal crossing distance, outbreeding depression | INTRODUCTIONIn insect-pollinated plants, pollen movement tends to be spatially limited (Levin & Kerster, 1974;Pluess et al., 2009;Sork & Smouse, 2006). Pollen deposition occurs frequently between neighbor plants, between flowers within the same individual, or even within the same flower (Jersáková & Johnson, 2006;Kropf & Renner, 2008). The resulting low pollen movement can affect the distribution of genetic variation within populations, increasing the proportion of identical-by-descent genotypes (Charlesworth & Charlesworth, 1999;Keller & Waller, 2002). Inbreeding, in turn, may have significant consequences on parental fecundity and progeny fitness (Keller & Waller, 2002;Lande & Schemske, 1985). A short-term negative effect is expected when outcrossing plant species are subjected to self-fertilization (Colling,

Efecto del ambiente y de caracteres morfológicos en variables bióticas y reproductivas de Pinguicula moranensis var. neovolcanica Zamudio (Lentibulariaceae) en Tlaxcala, México

“…Es contrastante que la viabilidad presente una relación negativa con las presas (Tabla 4 y 5), considerando que las poblaciones de P. moranensis producen más de 500 semillas por cápsula (Tabla 1), las semillas deberían disponer de reservorios energéticos para germinar y se asumiría baja consanguinidad en las poblaciones, con lo cual se incrementaría su viabilidad (Villegas & Alcalá 2018), en el tercer modelo (Tabla 6) se demostró la relación significativa semillas fértiles-viables. El porcentaje de germinación promedio fue superior al reportado por Pérez-Sánchez et al (2017) para P. moranensis (4 %) así como el reportado por Gonçalves et al (2008) para P. lusitánica (20 %), aunque más aproximado al que reportó Villegas et al (2020) con diferente medio de cultivo. La luz no fue un factor significante en el modelo de abundancia de presas, en contraparte, Alcalá & Domínguez (2003) encontraron que en P. moranensis la disponibilidad de presas se incrementa en sitios más sombreados y húmedos.…”

Long‐term progression of inbreeding depression in a Mediterranean ornithophilous shrub

“…ID is not only determined by genetic factors, but is also influenced by environment (Hedrick & Kalinowski, 2000; Jiménez et al, 1994; Suárez & Gianoli, 2005). Populations subjected to less stressful conditions should therefore have lower ID values (Armbruster & Reed, 2005), as has been seen in populations growing in greenhouse or controlled environments relative to wild populations (Dudash, 1990; Nebot et al, 2020; Villegas et al, 2020), but some studies have uncovered no relationship between stress intensity and ID (Angeloni et al, 2011; Sandner & Matthies, 2016).…”