  For a Nicholson's blowflies system with patch structure and multiple discrete
delays, we analyze several features of the global asymptotic behavior of its
solutions. It is shown that if the spectral bound of the community matrix is
non-positive, then the population becomes extinct on each patch, whereas the
total population uniformly persists if the spectral bound is positive. Explicit
uniform lower and upper bounds for the asymptotic behavior of solutions are
also given. When the population uniformly persists, the existence of a unique
positive equilibrium is established, as well as a sharp criterion for its
absolute global asymptotic stability, improving results in the recent
literature. While our system is not cooperative, several sharp threshold-type
results about its dynamics are proven, even when the community matrix is
reducible, a case usually not treated in the literature.
