Kouki Jari
Department of Zoology, University of Helsinki, P. Rautatiekatu 13, SF-00100, Helsinki, Finland.
Oecologia. 1993 Feb;93(1):42-47. doi: 10.1007/BF00321189.
Water-lily beetles prefer younger rather than older water-lily leaves as oviposition sites. By the time of hatching, however, young leaves have aged consieerably. Larval performance of the water-lily beetle was measured on different types of leaves of the yellow water-lily and compared with oviposition preference of females. The leaf types used in the experiments were categorized as (i) young, (ii) natal (medium-aged) and (iii) old. The natal leaves were the ones on which larvae from a particular egg-batch had hatched. There were two sets of experiments. First, larvae were raised from eggs to pupae on young and on old leaves. Second, the growth of the 1st-instar larvae was measured on young, natal, and old leaves. The development time from egg to pupa did not differ between young and old leaves, but larvae growing on young leaves attained a higher pupal weight. In the second experiment the 1st-instar larvae grew fastest on their natal leaves, but there was also variation in the growth rate of progeny from different egg-batches. Larval growth on young and old leaves did not differ significantly. Larvae tried to emigrate much less from natal than other types of leaves. Females tended to lay eggs on leaves where larval growth was fastest. It seems that medium-aged leaves are best for larval growth, but the leaf characteristics responsible for this remain unresolved.
睡莲甲虫更喜欢将较嫩而非较老的睡莲叶子作为产卵地点。然而，到孵化时，嫩叶已经老化了许多。研究人员在黄水莲的不同类型叶子上测量了睡莲甲虫的幼虫表现，并将其与雌虫的产卵偏好进行了比较。实验中使用的叶子类型分为：（i）嫩叶，（ii）出生地叶（中等年龄）和（iii）老叶。出生地叶是特定一批卵的幼虫孵化所在的叶子。实验分为两组。第一组，将幼虫从卵饲养至蛹，分别置于嫩叶和老叶上。第二组，测量一龄幼虫在嫩叶、出生地叶和老叶上的生长情况。从卵到蛹的发育时间在嫩叶和老叶之间没有差异，但在嫩叶上生长的幼虫达到了更高的蛹重。在第二个实验中，一龄幼虫在其出生地叶上生长最快，但不同批次卵的后代生长速度也存在差异。幼虫在嫩叶和老叶上的生长没有显著差异。幼虫从出生地叶迁出的尝试比从其他类型叶子迁出的少得多。雌虫倾向于在幼虫生长最快的叶子上产卵。似乎中等年龄的叶子最适合幼虫生长，但造成这种情况的叶子特征仍未明确。
