Understanding demographic responses to mortality is crucial to
predictive ecology. While classic ecological theory posits reductions in
population biomass in response to extrinsic mortality, models containing
realistic developmental change predict the potential for counterintuitive
increase in stage-specific biomass, i.e., biomass overcompensation.
Patterns of biomass overcompensation should be predictable based on
differences in the relative energetic efficiencies of juvenile maturation
and adult reproduction. Specifically, in populations where reproduction is
the limiting process, adult-specific mortality should enhance total
reproduction and thus juvenile biomass. We tested this prediction by
inducing an array of stage-specific harvesting treatments across replicate
populations of Daphnia pulex. In accordance with reproductive
regulation, the greatest biomass response occurred in the juvenile
Daphnia stage and this response occurred most strongly in response to
adult mortality. Nevertheless, we failed to detect significant biomass
overcompensation and instead report largely compensatory effects. In
total, our work demonstrates that knowledge of population structure is
necessary to accurately predict population dynamics, but cautions that
further research is needed to illuminate the factors generating overcompensatory
versus compensatory responses across natural
populations.