Many adult Lepidoptera nectar at flowers of plant species on which they also deposit their eggs. As a consequence, the same partner may act as both a pollinator and herbivore. How high are the costs associated with such herbivorous pollinators, relative to the potential benefits they confer? We addressed this question in the association between Datura wrightii (Solanaceae) and Manduca sexta (Sphingidae), which in southern Arizona, USA is both the plant’s most important pollinator (as adults) and most significant herbivore (as larvae). We manually inflicted two biologically relevant levels of artificial folivory (33% and 66% leaf removal) at two points during the growing season, to nearly 200 D. wrightii plants established in a common-garden outdoor plot. We recorded plant survival, growth, and several components of reproduction (bud, flower, and fruit production). We found no detectable effect of damage on plant growth rate, fruit set in the same or the following growing season, or plant volume or survival in the same or the following three seasons. These results suggest that D. wrightii may be highly tolerant of leaf consumption by the herbivorous offspring of its specialized, nectar-feeding pollinators. We argue that this mechanism would likely foster persistence of the pollination mutualism more effectively than would resistance to, or deterrence of, herbivores. Tolerance to the costs of mutualism is an underexplored phenomenon that could contribute to the stability of these interactions.

中文翻译：

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草食传粉者付出的代价有多高？

许多成年鳞翅目花蜜在植物的花朵上开花，它们也沉积了卵。结果，同一伙伴可能同时充当传粉者和草食动物。相对于它们带来的潜在利益，这种草粉授粉者的成本有多高？我们通过曼陀罗（茄科）和曼杜卡六a（天蛾科）之间的联系解决了这个问题，后者在美国亚利桑那州南部既是植物最重要的授粉媒介（成虫）又是最重要的食草动物（如幼虫）。在生长季节的两个时间点，我们手动施加了两个生物学上相关的人造叶肉水平（33％和66％的叶片去除率），达到近200头D. wrightii在户外花园中建立的植物。我们记录了植物的存活，生长和生殖的几个组成部分（芽，花和果实的产量）。我们没有发现损害对植物生长速度，在相同或以下生长季节的坐果，或在相同或以下三个季节的植物体积或存活的影响。这些结果表明，D。wrightii可能对由其专门供食花蜜的授粉媒介的草食后代对叶片的采食具有较高的耐受性。我们认为，与抵抗或威慑食草动物相比，这种机制可能更有效地促进授粉共生的持久性。 容忍互惠互利的代价是一个尚未被探索的现象，可能有助于这些互动的稳定。