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Spatial variation in female fertility related to interactions with flower consumers and pathogens in a forest metapopulation of Primula sieboldii
Author(s) -
Washitani Izumi,
Okayama Yasushi,
Sato Keiko,
Takahashi Hitomi,
Ohgushi Takayuki
Publication year - 1996
Publication title -
population ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.819
H-Index - 59
eISSN - 1438-390X
pISSN - 1438-3896
DOI - 10.1007/bf02515734
Subject(s) - biology , metapopulation , population , biological dispersal , botany , seed dispersal , ecology , demography , sociology
Antagonistic biological interactions with flower consumers and pathogens may influence reproductive success of flowering plants, affecting population dynamics and natural selection for floral traits. However, ecological and evolutionary consequences of the interactions may depend on both spatial and temporal patterns of the interactions. In a forest metapopulation of Primula sieboldii E. Morren, an endangered clonal plant species, we measured between‐subpopulation patterns of seed sets and interactions with an influential flower consumer, a rove beetle, Eusphalerum bosatsu Watanabe, and a specific smut fungal pathogen, Urocystis tranzschelina (Lavrov) Zundel (Ustilaginales), for three years. Mean female fertility (seed set per flower) for individual subpopulations fluctuated moderately among years but was highly variable within each year among the five subpopulations studied. In two subpopulations, the impact of Eusphalerum beetle, was sufficiently large to result in almost complete failure in seed production over eight years including the three study and five previous preliminary observation years. In the two other subpopulations, seed set failure was caused by infection by the smut fungus. Infected capsules which constitute 10–30% of the capsules produced in the subpopulations were filled with ustilospores instead of seeds. In the subpopulation that escaped flower damage by Eusphalerum beetles and smut fungal infection, seed sets of both pin and thrum flowers were much higher than in the other subpopulations. The spatial restriction of individual antagonistic agents to a part of subpopulations suggest that dispersal of the agents, as well as the mode of spatial subdivision of the plant population would be important for determining the overall effects of antagonistic interactions on plant performances at the metapopulation level.