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.