TY - JOUR
T1 - Self-pollination and its costs in a monoecious fig (Ficus aurea, Moraceae) in a highly seasonal subtropical environment
AU - Hossaert-Mckey, Martine
AU - Bronstein, Judith L.
N1 - Copyright:
Copyright 2018 Elsevier B.V., All rights reserved.
PY - 2001/4
Y1 - 2001/4
N2 - The unusual floral phenology of most monoecious figs, related to their highly specialized pollination mutualism with agaonid wasps, combines pronounced dichogamy at the level of inflorescences and individuals with population-level asynchrony in flowering. This floral phenology ensures that outcrossing strongly predominates. Fig populations may thus be expected to possess deleterious recessive alleles that lead to inbreeding depression when selfing does occur. However, whether monoecious figs are self-compatible and whether selfing results in inbreeding depression have never been investigated. Using wasps as "pollination tools" and exploiting infrequent overlap in male and female phases on the same tree, we conducted controlled selfed and outcrossed pollination experiments in Ficus aurea. Our results show that this species is totally self-compatible. No negative effects of selfing could be demonstrated on syconium retention, number of vacant ovaries, seed set, or seed germination. However, wasp production had a tendency to be higher after self-pollination. While it is possible that inbreeding depression is expressed at later developmental stages, its absence at the early stages we examined is nonetheless surprising for a plant expected to be highly outcrossed. It is likely that selection pressures other than avoidance of inbreeding are responsible for the evolution and maintenance of the unusual floral phenology of figs.
AB - The unusual floral phenology of most monoecious figs, related to their highly specialized pollination mutualism with agaonid wasps, combines pronounced dichogamy at the level of inflorescences and individuals with population-level asynchrony in flowering. This floral phenology ensures that outcrossing strongly predominates. Fig populations may thus be expected to possess deleterious recessive alleles that lead to inbreeding depression when selfing does occur. However, whether monoecious figs are self-compatible and whether selfing results in inbreeding depression have never been investigated. Using wasps as "pollination tools" and exploiting infrequent overlap in male and female phases on the same tree, we conducted controlled selfed and outcrossed pollination experiments in Ficus aurea. Our results show that this species is totally self-compatible. No negative effects of selfing could be demonstrated on syconium retention, number of vacant ovaries, seed set, or seed germination. However, wasp production had a tendency to be higher after self-pollination. While it is possible that inbreeding depression is expressed at later developmental stages, its absence at the early stages we examined is nonetheless surprising for a plant expected to be highly outcrossed. It is likely that selection pressures other than avoidance of inbreeding are responsible for the evolution and maintenance of the unusual floral phenology of figs.
KW - Ficus
KW - Florida
KW - Inbreeding depression
KW - Mutualism
KW - Phenology
KW - Pollination
KW - Seasonal environment
KW - Self-compatibility
KW - Selfing
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U2 - 10.2307/2657069
DO - 10.2307/2657069
M3 - Article
C2 - 11302855
AN - SCOPUS:0039785474
VL - 88
SP - 685
EP - 692
JO - American Journal of Botany
JF - American Journal of Botany
SN - 0002-9122
IS - 4
ER -