2.9 Asynchrony

You can also take the flowering times t_i into account by including the extra term h(t_i,t_j) when calculating the contribution of plant j to plant i. Two more parameters are then estimated, the average variance $\sigma_{mf}^2$ of the times at which single florets are susceptible to or emit pollen, and the degree of protandry $\delta$.

It may not be possible to estimate both of these parameters. Often, if there is a lot of overlap in time between different individuals the extra h(.,.) term will not make much difference and the likelihood will become very flat with respect to $\sigma_{mf}$ and $\delta$ directions. It's a good idea to remove delta to begin with. If this doesn't give you a sensible estimate of $\sigma_{mf}^2$, there is no hope that we will be able to estimate $\delta$.

The inclusion of the asynchrony term is turned off with the noasynchrony command.