The fitness cost involved in germination delay depends on biotic
interactions
We lastly tested whether the significant fitness cost of delayed
germination persisted without intraspecific competition or herbivory. To
avoid competition, E. annuus plants were transplanted to the
field with 2 weeks of the gap in germination (EG and DG) but without
overlap in their canopies. The field plot was covered with a mesh to
exclude natural herbivores (Fig 5a). Thereafter, we measured the growth
and reproduction of EG and DG plants over consecutive year.
Interestingly, EG and DG plants did not produce significantly different
rosette sizes after overwintering without competition (Fig 5b).
Moreover, DG plants produced more axillary branches than EG plants (Fig
5c, d). As in the aforementioned experiments, more axillary branches in
the DG plants resulted in greater flower production than in EG plants
(Fig 5e). Collectively, DG plants outperformed EG plants in environments
without competition or herbivory.