Karban Richard, Adler Frederick R
Department of Entomology, University of California, 95616, Davis, CA, USA.
Department of Mathematics, University of Utah, 84112, Salt Lake City, UT, USA.
Oecologia. 1996 Aug;107(3):379-385. doi: 10.1007/BF00328455.
Current models of induced plant defenses all assume that herbivory is predictable. Present damage must provide information about the likelihood of future attack. We tested this assumption by measuring the relationship between damage early in the season and the number of subsequent attacks by cotton leaf perforators, Bucculatrix thurberiella, to plants of wild cotton, Gossypium thurberi, at three sites in the Sonoran desert. Damage early in the season was a good predictor of the number of new mines initiated throughout the season for plants in Florida Canyon. This result was neither evidence for nor against induced resistance nor was it a consequence of induced resistance. This is because induced resistance has been found to affect survival of miners but previous damage did not affect the initiation of new mines. At two other sites, early damage was not related to future attacks. This difference in predictability of attack may be related to inducibility of plants since Florida Canyon was the only site that provided evidence of induced resistance in a previous study. We found no evidence that the usefulness of information based on early season damage decreased as the season progressed. Assessment of attacks on all shoots of the plant was more useful at predicting later damage to an assay shoot than was assessment of solely the assay shoot. Number of mines, produced only by G. thurberiella, was a better predictor of subsequent attacks by G. thurberiella than were chews and rasps which were made by many different herbivores. However, general chewing damage was a better indicator of the level of induction against G. thurberiella than was the more specific mining damage. Plants may respond more to chewing damage even though mining damage is a better predictor of future attacks.
当前诱导植物防御的模型都假定食草动物的行为是可预测的。当前的损害必须提供有关未来攻击可能性的信息。我们通过测量季节早期的损害与棉叶穿孔蛾（Bucculatrix thurberiella）随后对索诺兰沙漠三个地点的野生棉（Gossypium thurberi）植株的攻击次数之间的关系，来检验这一假设。对于佛罗里达峡谷的植株而言，季节早期的损害是整个季节新虫瘿数量的良好预测指标。这一结果既不是支持也不是反对诱导抗性的证据，也不是诱导抗性的结果。这是因为已发现诱导抗性会影响潜叶虫的存活，但先前的损害并未影响新虫瘿的形成。在其他两个地点，早期损害与未来攻击并无关联。攻击可预测性的这种差异可能与植物的可诱导性有关，因为在之前的一项研究中，佛罗里达峡谷是唯一提供诱导抗性证据的地点。我们没有发现证据表明基于季节早期损害的信息的有用性会随着季节的推进而降低。对植株所有枝条上的攻击进行评估，在预测对测定枝条的后期损害方面，比仅对测定枝条进行评估更有用。仅由棉叶穿孔蛾产生的虫瘿数量，比由许多不同食草动物造成的咀嚼和刮擦痕迹，更能预测棉叶穿孔蛾随后的攻击。然而，一般的咀嚼损害比更具特异性的虫瘿损害，更能表明对棉叶穿孔蛾的诱导水平。即使虫瘿损害是未来攻击的更好预测指标，植物可能对咀嚼损害反应更大。
