Strathmann R R, Fenaux L, Sewell A T, Strathmann M F
Biol Bull. 1993 Oct;185(2):232-239. doi: 10.2307/1542003.
Veliger larvae of mollusks were predicted to develop a larger velum relative to the larval shell when reared with scarce food. The functional consequences of such developmental plasticity would be (1) greater maximum capacity for capturing particles when food is scarce and (2) greater growth of structures retained in the postlarva when food is abundant. The hypothesis was tested by rearing veligers of the oyster Crassostrea gigas at high (near satiating) and low (growth limiting) concentrations of food. Veligers at the measured shell lengths (>200 {mu}m) had significantly larger velar lobes and longer prototrochal cilia than veligers reared in low concentrations of food. An analogous response to food levels (relatively longer ciliated band when food is scarce) has now been found for larvae as disparate as oyster veligers and sea urchin plutei. These observations suggest that functionally similar examples of developmental plasticity in the growth of larval parts have evolved more than once and may be widespread. An alternative interpretation is that differential mortality or growth in a genetically heterogeneous batch of oyster larvae results in advanced veligers of different forms at different concentrations of food. Both interpretations suggest an adaptive advantage to growing a larger apparatus for clearing particles from suspension when food is scarce and shifting materials to growth of postlarval structures (shell and associated structures) when food is abundant.
软体动物的面盘幼虫在食物稀缺的环境中饲养时，预计会发育出相对于幼虫壳更大的面盘。这种发育可塑性的功能后果将是：（1）在食物稀缺时捕获颗粒的最大能力更强；（2）在食物丰富时，后期幼虫中保留结构的生长速度更快。通过在高（接近饱食）和低（生长受限）食物浓度下饲养太平洋牡蛎的面盘幼虫来验证这一假设。在测量的壳长（>200μm）时，与在低食物浓度下饲养的面盘幼虫相比，面盘幼虫具有明显更大的面盘叶和更长的原纤毛带。现在已经发现，牡蛎面盘幼虫和海胆长腕幼虫等不同种类的幼虫对食物水平有类似的反应（食物稀缺时纤毛带相对更长）。这些观察结果表明，幼虫部分生长中功能相似的发育可塑性例子已经不止一次进化，而且可能很普遍。另一种解释是，在基因异质的一批牡蛎幼虫中，不同的死亡率或生长速度导致在不同食物浓度下出现不同形态的晚期面盘幼虫。两种解释都表明，当食物稀缺时，生长一个更大的从悬浮液中清除颗粒的器官，而当食物丰富时，将物质转移到后期幼虫结构（壳和相关结构）的生长上具有适应性优势。
