Department of Entomology and Nematology, University of California, Davis, California, USA.
Division of Integrated Science and Engineering, California Department of Water Resources, West Sacramento, California, USA.
Ecology. 2023 Jan;104(1):e3854. doi: 10.1002/ecy.3854. Epub 2022 Nov 6.
Phenological shifts have the potential to change species interactions, but relatively few studies have used experimental manipulations to examine the effects of variation in timing of an interspecific interaction across a series of life stages of a species. Although previous experimental studies have examined the consequences of phenological timing in plant-herbivore interactions for both plants and their herbivores, less is known about their effects on subsequent plant reproduction. Here, we conducted an experiment to determine how shifts in the phenological timing of monarch (Danaus plexippus) larval herbivory affected milkweed (Asclepias fascicularis) host plant performance, including effects on growth and subsequent effects on flower and seed pod phenology and production. We found that variation in the timing of herbivory affected both plant growth and reproduction, with measurable effects several weeks to several months after herbivory ended. The timing of herbivory had qualitatively different effects on vegetative and reproductive biomass: early-season herbivory had the strongest effects on plant size, whereas late-season herbivory had the strongest effects on the production of viable seeds. These results show that phenological shifts in herbivory can have persistent and qualitatively different effects on different life stages across the season.
物候变化有可能改变物种间的相互作用，但相对较少的研究使用实验操作来研究在物种的一系列生命阶段中，同种相互作用的时间变化的影响。尽管先前的实验研究已经检验了植物-食草动物相互作用中物候定时对植物及其食草动物的后果，但对于它们对随后的植物繁殖的影响知之甚少。在这里，我们进行了一项实验，以确定帝王蝶（Danaus plexippus）幼虫取食的物候时间变化如何影响乳草（Asclepias fascicularis）宿主植物的性能，包括对生长的影响以及对随后的花和种子荚的物候和产量的影响。我们发现，取食时间的变化既影响植物的生长又影响植物的繁殖，在取食结束后数周到数月内都可以测量到影响。取食的时间对营养和生殖生物量有不同的定性影响：早期取食对植物大小的影响最强，而晚期取食对有活力的种子的产量影响最强。这些结果表明，取食物候的变化可能在整个季节对不同的生命阶段产生持久和定性不同的影响。
