This exercise suggests that growing to a much larger size typically doesn’t pay off in more eggs laid, and the optimal female size predicted by the model is relatively close to what is actually observed.
The paper concludes that one important reason why insects with a high capacity of larval growth do not evolve towards larger sizes may be that the fecundity [# of offspring produced] benefit is in fact relatively limited under natural conditions.
Mothra To the Rescue!
What Keeps Insects Small? Time Limitation during Oviposition Reduces the Fecundity Benefit of Female Size in a Butterfly. 2007. K. Gotthard, D. Berger, and R. Walters. The American Naturalist, volume 169 (2007), upcoming paper.