Data from: Na+/K+-ATPase resistance and cardenolide sequestration: basal adaptations to host plant toxins in the milkweed bugs (Hemiptera: Lygaeidae: Lygaeinae)

Despite sequestration of toxins being a common coevolutionary response to plant defence in phytophagous insects, the macroevolution of the traits involved is largely unaddressed. Using a phylogenetic approach comprising species from four continents, we analysed the ability to sequester toxic cardenolides in the hemipteran subfamily Lygaeinae, which is widely associated with cardenolide-producing Apocynaceae. In addition, we analysed cardenolide resistance of their Na+/K+-ATPases, the molecular target of cardenolides. Our data indicate that cardenolide sequestration and cardenolide-resistant Na+/K+-ATPase are basal adaptations in the Lygaeinae. In two species that shifted to non-apocynaceous hosts, the ability to sequester was secondarily reduced, yet Na+/K+-ATPase resistance was maintained. We suggest that both traits evolved together and represent major coevolutionary adaptations responsible for the evolutionary success of lygaeine bugs. Moreover, specialization on cardenolides was not an evolutionary dead end, but enabled this insect lineage to host shift to cardenolide-producing plants from distantly related families.尽管毒素隔离（toxin sequestration）是植食性昆虫应对植物防御的常见协同进化响应，但针对此类相关性状的宏观进化研究迄今仍未得到充分关注。本研究采用涵盖四大洲物种的系统发育分析方法，对广泛与产强心苷（cardenolides）夹竹桃科（Apocynaceae）植物形成关联的半翅目长蝽亚科（Lygaeinae）类群的有毒强心苷隔离能力展开了分析。此外，本研究还探究了其钠钾ATP酶（Na+/K+-ATPase）的强心苷抗性——该酶正是强心苷的分子作用靶点。研究数据表明，强心苷隔离能力与抗强心苷钠钾ATP酶均为长蝽亚科的祖先适应性性状。在两类转换至非夹竹桃科寄主的物种中，其强心苷隔离能力发生了次生退化，但钠钾ATP酶的抗性仍得以保留。我们认为这两类性状协同进化，是支撑长蝽亚科昆虫演化成功的核心协同适应性性状。此外，对强心苷类植物的特化并非演化死胡同，反而使得该昆虫演化支系能够转而取食来自不同远缘科的产强心苷植物。