Since nitrogen (N) is a limiting nutrient for many herbivores, variations in dietary N content will affect their fitness. In the Seto Inland Sea, Japan, the N content of green algae, Ulva spp., has in recent years shown a tendency to decrease due to the progress of oligotrophication. We investigated the effect of the reduction in N content of Ulva australis on the survival, growth, and reproduction of the herbivorous amphipod Ampithoe tarasovi under laboratory conditions. When amphipods were fed U. australis with a low N content, survivorship was not affected. However, the growth of both males and females was impaired due to the reduced molt increment and extended intermolt period. Furthermore, the low N content delayed female maturation and reduced the percentage of ovulation alongside the brood size and number of broods. These results suggest that the total number of eggs produced in the lifetime of a female in A. tarasovi is markedly reduced under low N food conditions. Therefore, in coastal waters where dissolved inorganic nitrogen (DIN) is deficient, because the tissue N content of algae reflects the DIN concentration in the ambient water, the population density of A. tarasovi may decrease due to the reduction in the number of viable offspring.

由于氮（N）是许多草食动物的限制性营养素，因此饮食中氮含量的变化会影响其适应性。在濑户内海，日本，绿藻的N含量，石莼属，近几年由于所示降低到贫营养的进步的趋势。我们研究了在实验室条件下降低澳大利亚石Ul的氮含量对草食性两足纲Ampithoe tarasovi的存活，生长和繁殖的影响。当片脚饲喂U.芦苇氮含量低时，存活率没有受到影响。然而，由于减少的蜕皮增加和延长的蜕皮期，男性和女性的生长都受到了损害。此外，低氮含量延迟了女性的成熟，并降低了排卵的百分比，同时减少了育雏的数量和育雏数量。这些结果表明，在低氮食物条件下，塔拉索维曲霉雌性一生中产卵的总数明显减少。因此，在溶解性无机氮（DIN）不足的沿海水域，由于藻类的组织N含量反映了环境水中的DIN浓度，塔拉索维A曲霉的种群密度可能由于存活后代数量的减少而降低。 。