For many biological questions, age, or stage, structured models are useful as they ‘include more biologically significant mechanisms, more experimentally measurable parameters, more environmental variability and more important nonlinear processes’ than unstructured models, and ‘the resulting dynamics can be profoundly different’ from those of unstructured models (Caswell et al. 1997
: 10). Although the unstructured models of Ginzburg & Taneyhill (1994)
and Inchausti & Ginzburg (1998)
provide a good fit to a number of extant forest Lepidoptera and microtine rodent time series, there has been no investigation of the impacts of maternal effects on complex, biologically structured, population models (although Inchausti & Ginzburg (1998
; Appendix 1) shows that maternal-effects cycles are also plausible within a simple age-structured model). With structured models, it might be possible for the different age/stage classes to fluctuate out of synchrony, such that the total population size remains unaffected by the destabilizing maternal effects which are shown in unstructured models.