Data from: Secondary reproduction in the herbaceous monocarp Lobelia inflata: time-constrained primary reproduction does not result in increased deferral of reproductive effort

Background: Although semelparity is a life history characterized by a
single reproductive episode within a single reproductive season, some
semelparous organisms facultatively express a second bout of reproduction,
either in a subsequent season (“facultative iteroparity”) or later within
the same season as the primary bout (“secondary reproduction”). Secondary
reproduction has been explained as the adaptive deferral of reproductive
potential under circumstances in which some fraction of reproductive
success would otherwise have been lost (due, for example, to inopportune
timing). This deferral hypothesis predicts a positive relationship between
constraints on primary reproduction and expression of secondary
reproduction. The herbaceous monocarp Lobelia inflata has been observed
occasionally to express a secondary reproductive episode in the field.
However, it is unknown whether secondary reproduction is an example of
adaptive reproductive deferral, or is more parsimoniously explained as the
vestigial expression of iteroparity after a recent transition to
semelparity. Here, we experimentally manipulate effective season length in
each of three years to test whether secondary reproduction is a form of
adaptive plasticity consistent with the deferral hypothesis. Results: Our
results were found to be inconsistent with the adaptive deferral
explanation: first, plants whose primary reproduction was time-constrained
exhibited decreased (not increased) allocation to subsequent secondary
reproduction, a result that was consistent across all three years; second,
secondary offspring—although viable in the laboratory—would not have the
opportunity for expression under field conditions, and would thus not
contribute to reproductive success. Conclusions: Although alternative
adaptive explanations for secondary reproduction cannot be precluded, we
conclude that the characteristics of secondary reproduction found in L.
inflata are consistent with predictions of incomplete or transitional
evolution to annual semelparity.