Shefferson and Simms 2007

		Shefferson, R.P. and E.L. Simms. 2007. Costs and benefits of fruiting to future
		reproduction in two dormancy-prone orchids. Journal of Ecology 95:865-875.

Summary
1 Reproduction is expected to occur at a cost to survival, growth, or future
reproduction. However, trade-offs in long-lived, clonal herbs have proven difficult to
assess, particularly when they are prone to adult dormancy.

2 We assessed the costs of fruiting in a study of two species of lady’s slipper orchid,
Cypripedium candidum and C. parviflorum, growing sympatrically in a wet meadow in
northeastern Illinois, USA, from 2000 to 2005.

3 First, we characterized flowering and fruiting in both populations. We found some
differences between species, with 68.6 ± 5.7% (mean ± SE) and 43.5 ± 1.4% of
sprouting plants flowering, while 33.6 ± 10.0% and 33.5 ± 8.1% of flowering plants
fruited in C. candidum and C. parviflorum, respectively.

4 Next, we tested the survival, sprouting, and flowering response to current fruiting
using multistate mark-recapture statistics. The best-fit model posited no cost of
fruiting. However, according to a model parsimonious with the best-fit model, fruiting
may have resulted in a small cost to survival visible primarily in small-sized
individuals of C. parviflorum (decrease from 0.846 in non-fruiting but flowering plants
to 0.824 in fruiting plants). In all cases, fruiting resulted in an increased probability of
future flowering, suggesting that reproduction may have a higher priority in resource
allocation than survival.

5 Finally, we tested the effects of fruiting on future fruiting using logistic regression for
two years in which fruiting was particularly high, but detected no change in the
probability of fruiting after fruiting.

6 Fruiting may increase in response to internal cues, perhaps related to nutrient
uptake or storage, in addition to the obvious effects of pollination. The result may be
that plants with greater access to nutrients or with greater stored reserves are more
likely to flower each season. We suggest a need for further research exploring the
internal mechanisms governing fruiting response in long-lived, clonal herbs.

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Shefferson and Simms 2007