Species that reproduce repeatedly over their lifetimes typically allocate energy to both their reproductive activities and their non-reproductive, somatic activities. Fisher (1930) first posed the evolutionary problem of understanding not merely the physiological mechanism of this energy allocation, but also the ultimate question of how the allocation pattern affects an organism's long-term reproduction. Williams (1966) extended this idea, examining the balance of an organism's immediate reproductive interests and its future reproductive potential. Fisher first developed the concept of reproductive value, an organism's expectation of future offspring. Williams partitioned reproductive value into a component for current reproduction, and residual reproductive value which represents future reproduction beyond the current reproductive activities. Energy allocated to current reproduction entails costs to somatic development, and thus potentially to reductions in residual reproductive value. Tinkle (1969) suggested various reproductive behaviors in lizards, including bright coloration, courtship and parental care, among others, that may decrease life expectancy and therefore be costs of reproduction. Gadgil and Bossert (1970) determined that the amount of growth should be regulated to maximize the individual's fitness. For some indeterminate growth organisms, reproduction could detract from growth and therefore decrease fitness at a later stage. Snell and King (1977) have data suggesting an inverse relationship between reproductive rate and lifespan. Law (1979) showed that high rates of reproduction early in life lead to smaller plant size and possibly increased mortality, also. Calow (1979) emphasizes the importance of finding these negative correlations between reproductive output and residual reproductive value and possibly even understanding the causal basis for them. Some costs of reproduction can be demonstrated in the terrestrial isopod, Armadillidium vulgare. Armadillidium vulgare exhibits indeterminate growth; larger females can be nearly ten times the live weight of the smallest sexually mature females. Clearly females invest a large portion of the energy they assimilate to somatic growth instead of reproduction. In