Data from: Plant-derived differences in the composition of aphid honeydew and their effects on colonies of aphid-tending ants

In plant–ant–hemipteran interactions, ants visit plants to consume the honeydew produced by phloem-feeding hemipterans. If genetically based differences in plant phloem chemistry change the chemical composition of hemipteran honeydew, then the plant's genetic constitution could have indirect effects on ants via the hemipterans. If such effects change ant behavior, they could feed back to affect the plant itself. We compared the chemical composition of honeydews produced by Aphis nerii aphid clones on two milkweed congeners, Asclepias curassavica and Asclepias incarnata, and we measured the responses of experimental Linepithema humile ant colonies to these honeydews. The compositions of secondary metabolites, sugars, and amino acids differed significantly in the honeydews from the two plant species. Ant colonies feeding on honeydew derived from A. incarnata recruited in higher numbers to artificial diet, maintained higher queen and worker dry weight, and sustained marginally more workers than ants feeding on honeydew derived from A. curassavica. Ants feeding on honeydew from A. incarnata were also more exploratory in behavioral assays than ants feeding from A. curassavica. Despite performing better when feeding on the A. incarnata honeydew, ant workers marginally preferred honeydew from A. curassavica to honeydew from A. incarnata when given a choice. Our results demonstrate that plant congeners can exert strong indirect effects on ant colonies by means of plant-species-specific differences in aphid honeydew chemistry. Moreover, these effects changed ant behavior and thus could feed back to affect plant performance in the field.在植物-蚂蚁-半翅目昆虫（hemipteran）三方互作体系中，蚂蚁会造访植物以取食由取食韧皮部（phloem）的半翅目昆虫所分泌的蜜露（honeydew）。若植物韧皮部化学成分的遗传介导差异改变了半翅目昆虫蜜露的化学组成，那么植物的遗传特征可通过半翅目昆虫对蚂蚁产生间接影响。若此类影响改变了蚂蚁的行为，则可反过来作用于植物本身。 本研究比较了夹竹桃蚜（Aphis nerii）克隆系在两种马利筋同属物种——马利筋（Asclepias curassavica）与缘毛马利筋（Asclepias incarnata）上所分泌的蜜露的化学成分，并检测了实验用阿根廷蚁（Linepithema humile）群落对这些蜜露的响应。 两种植物来源的蜜露在次生代谢物、糖类与氨基酸的组成上均存在显著差异。取食缘毛马利筋来源蜜露的蚁群，其对人工饲料的招募个体数量更多，蚁后与工蚁的干重更高，且工蚁种群数量略高于取食马利筋来源蜜露的蚁群。相较于取食马利筋来源蜜露的蚂蚁，取食缘毛马利筋来源蜜露的蚂蚁在行为学实验中也表现出更强的探索性。 尽管取食缘毛马利筋来源蜜露时蚂蚁的表现更优，但当提供两种蜜露选择时，工蚁仍轻微偏好马利筋来源的蜜露。 本研究结果表明，马利筋同属物种可通过蚜虫蜜露化学组成的植物物种特异性差异，对蚂蚁群落产生强烈的间接影响。此外，这些影响会改变蚂蚁的行为，进而可反过来作用于野外环境中的植物生长表现。