Growth rates of newly-metamorphosed urchins from a single spawning event (three males and three females) were highly variable, despite being held en masse under identical environmental and nutritional conditions. As individuals reached ~5 mm diameter (0.07–0.10 g wet weight), they were placed in growth trials (23 dietary treatments containing various nutrient profiles). Elapsed time from the first individual entering the growth trials to the last individual entering was 121 days (N = 170 individuals). During the five-week growth trials, urchins were held individually and proffered a limiting ration to evaluate growth rate and production efficiency. Growth rates among individuals within each dietary treatment remained highly variable. Across all dietary treatments, individuals with an initially high growth rate (entering the study first) continued to grow at a faster rate than those with an initially low growth rate (entering the study at a later date), regardless of feed intake. Wet weight gain (ranging from 0.13–3.19 g, P <0.0001, R2 = 0.5801) and dry matter production efficiency (ranging from 25.2–180.5%, P = 0.0003, R2 = 0.6162) were negatively correlated with stocking date, regardless of dietary treatment. Although canalization of growth rate during en masse early post-metamorphic growth is possible, we hypothesize that intrinsic differences in growth rates are, in part, the result of differences (possibly genetic) in production efficiencies of individual Lytechinus variegatus. That is, some sea urchins are more efficient in converting feed to biomass. We further hypothesize that this variation may have evolved as an adaptive response to selective pressure related to food availability.

中文翻译：

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生长速度与海胆 Lytechinus variegatus 幼体的生产效率相关

尽管在相同的环境和营养条件下集体饲养，但单次产卵事件（三只雄性和三只雌性）的新变态海胆的生长率差异很大。当个体直径达到约 5 毫米（0.07-0.10 克湿重）时，它们被置于生长试验中（包含各种营养成分的 23 种饮食治疗）。从第一个个体进入生长试验到最后一个个体进入所经过的时间是 121 天（N = 170 个体）。在为期五周的生长试验中，海胆被单独饲养并提供限制日粮以评估生长速度和生产效率。每种饮食治疗中个体的生长率仍然存在很大差异。在所有饮食治疗中，无论采食量如何，最初生长速度较高的个体（首先进入研究）的生长速度比最初生长速度较低的个体（稍后进入研究）的生长速度更快。湿增重（0.13-3.19 克，磷<0.0001，R2= 0.5801）和干物质生产效率（范围为 25.2–180.5%，磷= 0.0003, R2= 0.6162）与放养日期呈负相关，无论饮食处理如何。尽管在变质后早期集体生长过程中生长速率的管道化是可能的，但我们假设生长速率的内在差异部分是个体生产效率差异（可能是遗传的）的结果。斑叶荔枝。也就是说，一些海胆将饲料转化为生物质的效率更高。我们进一步假设这种变异可能是作为对与食物供应相关的选择压力的适应性反应而进化的。