Data from: The selective advantage of a mast-flowering behavior in Veratrum album subsp. oxysepalum: Implications of the predator satiation hypothesis

Premise: The synchronous highly variable flower or seed production among
years within a population– i.e., masting – has been reported in numerous
perennial plants. Although ecological advantages of masting are recognized
as the enhancement of pollination efficiency and/or escape from predator
attack, little is known about the degree of these advantages and the
variation in masting behavior among populations of conspecific plants.
Methods: We observed flowering ramet density and reproductive
success (fruit-set success and herbivorous damage) of a perennial herb,
Veratrum album subsp. oxysepalum, across six lowland and six alpine
populations in northern Japan during 2–3 years. We then analyzed the
relationship between floral density and reproductive success to clarify
the ecological significance of mast flowering. Furthermore, flowering
intervals of individual plants were estimated by counting annual scars on
rhizomes. Results: Mast flowering was observed in most
populations, but flowering intervals of individual plants were shorter in
the alpine populations compared with the lowland populations. Floral
damage by stem borers (dipteran larvae) and seed predation by lepidopteran
larvae were intense in the lowland populations. The seed production of
individual ramets increased with higher floral density owing to the
effective avoidance of floral-stem damage and seed predation. Although
stem borers were absent in alpine habitat, seed predation decreased with
higher floral density also in the alpine populations. Pollination success
was independent of floral density in both the alpine and lowland
populations.  Conclusions: These results strongly
support the predator satiation hypothesis for the mast flowering behavior
in this species.