Modeling social insect populations II: Optimal reproductive strategies in annual eusocial insect colonies

Summary We examined the optimal reproductive strategies for eusocial insects with an annual life cycle. A model is constructed for the growth of workers and reproductives as a function of the resources allocated to each. We then compute the allocation schedule which yields the maximum number of reproductives by season's end. Field observations appear to confirm the prediction of our model: the optimal strategy is to invest in colony growth until approximately one generation before the season's end, whereupon worker production ceases and reproductive effort is switched entirely to producing queens and males. Similar all-or-none strategies are observed in other biological contexts, and their optimality is proven here. Finally, we calculate the fraction of the total season's resources allocated to reproductives from which we can estimate the ergonomic efficiency of the colony with respect to reproductive success.