Reavey Duncan
Department of Biology, University of York, YO1 5DD, York, UK.
Oecologia. 1991 Jul;87(2):257-264. doi: 10.1007/BF00325264.
The effects of leaf quality on caterpillar performance are frequently investigated, as are the feeding preferences of caterpillars, but rarely are the two considered together to see how preferences match performance. I looked at the preferences and performance of the specialist feeder Achlya flavicornis and the generalist Spilosoma luteum on Betula pendula leaves which were artificially damaged, mined or left undamaged, and on leaves of different ages. Often feeding preferences were not for the leaf types that gave faster development, larger pupae or greater survival. A. flavicornis preferred medium aged to older leaves though medium aged leaves produced smaller pupae. They did not discriminate between young and medium aged leaves, though larvae fed young leaves developed more slowly, and had lower survival and lower adult emergence. S. luteum larvae did not discriminate between damaged and undamaged leaves, though feeding on damaged leaves gave smaller pupae and lower adult emergence. I suggest that generalists like S. luteum might be unable to make feeding choices between leaves that are on the same tree and vary only slightly because populations are exposed to much greater variation across the wide range of potential food plants individuals may encounter. Possible differences in within-plant feeding selectivity between generalists and specialists should be investigated. A. flavicornis is a leaftier for which selection of a suitable leaf for tying could be more important in the first instance than feeding considerations. Larvae preferred younger to older leaves for tying, and larvae tended to feed on the tied leaves, so tying preferences explain the initial feeding preferences.
叶片质量对毛虫生长表现的影响常被研究，毛虫的取食偏好也同样如此，但很少将二者结合起来考察偏好与生长表现的匹配情况。我研究了专食性取食者黄角水螟（Achlya flavicornis）和广食性者黄斑污灯蛾（Spilosoma luteum）对人工损伤、遭潜叶虫侵害或未受损的欧洲白桦（Betula pendula）叶片以及不同树龄叶片的偏好和生长表现。通常，毛虫的取食偏好并非针对那些能使其发育更快、蛹更大或存活率更高的叶片类型。黄角水螟更喜欢取食中年叶片而非老叶，尽管取食中年叶片产生的蛹较小。它们对幼叶和中年叶片没有偏好，不过取食幼叶的幼虫发育更慢，存活率更低，成虫羽化率也更低。黄斑污灯蛾幼虫对受损和未受损叶片没有偏好，尽管取食受损叶片产生的蛹更小，成虫羽化率也更低。我认为，像黄斑污灯蛾这样的广食性者可能无法在同一棵树上仅略有差异的叶片之间做出取食选择，因为在个体可能遇到的广泛潜在食物植物范围内，种群面临的差异要大得多。应该研究广食性者和专食性者在植物内部取食选择性上可能存在的差异。黄角水螟是一种卷叶蛾，对于它来说，首先选择合适的叶片用于卷叶可能比取食考虑更为重要。幼虫在卷叶时更喜欢幼叶而非老叶，并且幼虫倾向于取食卷好的叶片，所以卷叶偏好解释了最初的取食偏好。
