Chemical Ecology of Swallowtail Butterflies

这项研究的长期目标是发现植物之间的化学相似性和差异如何影响植物和以它们为食的昆虫之间的联系。 大多数植食昆虫都是专家，只在少数几种植物上取食和产卵。 它们主要通过闻植物产生的特有气味或品尝植物组织或植物表面的化学化合物的混合物来寻找和识别特定的食用植物。 事实上，被特定种类的昆虫攻击的植物通常都有一种或多种不寻常的化合物。 这表明，昆虫在食物中添加新植物种类的能力是由特定化合物的共同出现促进的。凤蝶科凤蝶属凤蝶属凤 在接下来的三年里，研究人员计划集中研究黑凤蝶（Papilio polyxenes），并确定为什么这个物种的雌性几乎从不在胡萝卜科（Apiaceae）以外的植物上产卵，但却接受这个科中的各种不同物种。 至少在某种程度上，雌性通过脚上的味觉感受器和触角上的气味感受器来识别产卵的植物。 这些刺激性化合物中有几种已经被鉴定出来。 研究人员将在三种常见的寄主物种，即胡萝卜、野生防风草和毒芹中完成对黑燕尾的这些刺激物的鉴定。 然后，PI将确定刺激剂的混合物是否具有共同的化合物，或者每种植物是否被不同的刺激剂化合物识别。 在这三种食物植物中，个体黑燕尾蝶雌性的偏好将与刺激提取物的偏好进行比较，以确定这些是否是不同物种之间寄主偏好的主要原因。 PI将测量个体雌性偏好的变化，并抚养它们的后代，以便PI可以比较它们雌性后代的相应偏好。 这些实验将告诉我们，女性之间的差异是否（至少部分是）来自于对化学信号反应的遗传差异。尽管最近取得了进展，主要是在欧洲和日本，但人们对昆虫识别寄主植物的化学混合物知之甚少，更不用说相关感觉机制的遗传学了。 这项研究应该有助于基础知识所需的新作物品种的明智部署，其化学已被基因工程修改。

The long-term goal of this research is to discover how chemicalsimilarities and differences among plants have influenced associationsbetween plants and the insects that feed on them. Most plant-feedinginsects are specialists, feeding and laying their eggs on only a few plantspecies. They find and identify their particular food plants largely bysmelling characteristic odors produced by the plants or by tastingcharacteristic mixtures of chemical compounds in the plant tissues or onthe plant surfaces. Indeed, plant species that are attacked by aparticular species of insect typically share one or more kinds of unusualchemical compounds. This suggests that the ability of insects to add newplant species to their diet is facilitated by the shared occurrence ofparticular compounds. The swallowtail butterflies (family Papilionidae) are used as amodel system in this research because their classification and larval foodplants are especially well known. During the next three years, the PIs plan toconcentrate on the black swallowtail (Papilio polyxenes) and to determinewhy females of this species almost never lay their eggs on plants outsidethe carrot family (Apiaceae) and yet accept a wide range of differentspecies within this family. At least in part, females identify plants onwhich to lay their eggs by detecting stimulant compounds with tastereceptors on their feet and by odor receptors in their antennae. Severalof these stimulant compounds have already been identified. The PIs willcomplete the identification of these stimulants for the black swallowtailin three common host species, namely carrot, wild parsnip, and poisonhemlock. The PIs will then determine whether the mixtures of stimulants sharecompounds in common or whether each plant is recognized by a different setof stimulant compounds. Preferences of individual black swallowtailfemales among the three food-plant species will be compared withpreferences for stimulant extracts to determine whether these are primarilyresponsible for host preference among different species. The PIs will measurevariation in the preferences of individual females and raise their progenyso that the PIs can compare the corresponding preferences of their femaleoffspring. These experiments will tell us whether variation among femalesresults, at least in part, from inherited differences in responses tochemical cues. Despite recent progress, mostly in Europe and Japan, remarkablylittle is known of the chemical mixtures by which insects recognize theirhost plants, let alone of the genetics underlying the relevant sensorymechanisms. This research should contribute to the basic knowledgerequired for the wise deployment of new crop varieties whose chemistry hasbeen modified by genetic engineering.