Pollen limitation, fruit abortion, and autonomous selfing in three populations of the perennial herbRuellia nudiflora

Abstract

Multiple factors determine plant reproductive success and their influence may vary spatially. This study addresses several factors influencing female reproductive success in three populations of Ruellia nudiflora, specifically we: (i) determine if fruit set is pollen‐limited and if pollinator visitation rates are related to this condition; (ii) estimate fruit set via autonomous self‐pollination (AS) and relate it to the magnitude of herkogamy; and (iii) evaluate if fruit abortion is a post‐pollination mechanism that determines the magnitude of pollen limitation. At each site we marked 35 plants, grouped as: unmanipulated control (C) plants subjected to open pollination, plants manually cross‐pollinated (MP), and plants excluded from pollinators and only able to self‐pollinate autonomously (AS). Fruit set was greater for MP relative to C plants providing evidence for pollen limitation, while a tendency was observed for lower fruit abortion of MP relative to C plants suggesting that fruit set is influenced not only by pollen delivery per se, but also by subsequent abortion. In addition, although pollinator visits varied significantly among populations, the magnitude of pollen limitation did not, suggesting that pollinator activity was not relevant in determining pollen limitation. Finally, fruit set tended to decrease with the degree of herkogamy for AS plants, but this result was inconclusive. These findings have contributed to identify which factors influence reproductive success in populations of R. nudiflora, with potentially relevant implications for population genetic structure and mating system evolution of this species.

Effects of arbuscular mycorrhizal fungi on above‐ground tri‐trophic interactions are contingent upon plant genetic effects of cross type in the perennial herb Ruellia nudiflora

“…This is to be expected as herbivores directly depend upon plant abundance or traits associated with nutritional quality, whereas predators are in many cases indirectly influenced by plants via effects on herbivores (Johnson, ). We do note, however, that previous work in this system has shown that indirect effects of parasitoids on R. nudiflora seed output are influenced by soil nutrient availability (Abdala‐Roberts et al., ), calling for further work testing whether the observed effects of cross type and AMF on parasitoids are dependent upon the abiotic context.…”

“…This species produces cleistogamous (CL) flowers, which do not open and undergo obligate self‐pollination as well as chasmogamous (CH) flowers, which have open corollas, are visited by pollinators, and undergo cross‐pollination. CH flowers also frequently exhibit automatic self‐pollination upon corolla dehiscence (Abdala‐Roberts, Marrufo‐Zapata, Arceo‐Gómez, & Parra‐Tabla, ). Fruits are dry and dehiscent capsules, and seeds are dispersed ballistically (Munguía‐Rosas et al., ).…”

“…Fruit size is correlated with seed number and previous work has shown that there is no difference in size between attacked fruits and fruits not attacked by the caterpillar. This indicates that using the mean number of seeds per fruit from fruits that were not attacked is a reasonable estimate of the hypothetical or potential seed number in attacked fruits had they not been attacked and their seeds consumed (Abdala‐Roberts et al., ). We estimated the proportion of saved seeds per fruit and then averaged these proportions across fruits per plant for statistical analysis.…”

Genetic diversity, outcrossing rate, and demographic history along a climatic gradient in the ruderal plant Ruellia nudiflora (Acanthaceae)

“…This species is self-compatible and exhibits varying low levels of pollen limitation, but its outcrossing rate and other mating system traits are unknown (Abdala-Roberts, Marrufo-Zapata, Arceo-Gómez, & Parra-Tabla, 2012). Additionally, populations of R. nudiflora in the Yucatán Peninsula display drastic spatial variation in floral traits such as degree of herkogamy (Marrufo, 2011).…”

Reproductive biology of the narrow endemic Anchusa littoreaMoris (Boraginaceae), an endangered coastal Mediterranean plant

“…Plant reproductive success is determined by intrinsic characteristics of the reproductive system of a species, as well as by extrinsic abiotic and biotic factors (Abdala-Roberts et al, 2014).…”