Divergence in cryptic leaf colour provides local camouflage in an alpine plant
Proceedings of the Royal Society B: Biological Sciences
Royal Society, The
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Under temporary indefinite embargo pending publication by The Royal Society
The efficacy of camouflage through background matching is highly environment-dependent, often resulting in intraspecific colour divergence in animals to optimize crypsis in different visual environments. This phenomenon is largely unexplored in plants, although several lines of evidence suggest they do use crypsis to avoid damage by herbivores. Using Corydalis hemidicentra, an alpine plant with cryptic leaf colour, we quantified background matching between leaves and surrounding rocks in five populations based on an approximate model of their butterfly enemy’s colour perception. We also investigated the pigment basis of leaf colour variation and the association between feeding risk and camouflage efficacy. We show that plants exhibit remarkable colour divergence between populations, consistent with differences in rock appearances. Leaf colour varies because of a different quantitative combination of two basic pigments: chlorophyll, anthocyanin, plus different air spaces. As expected, leaf colours are better matched against their native backgrounds than against foreign ones in the eyes of the butterfly. Furthermore, improved crypsis tends to be associated with a higher level of feeding risk. These results suggest that divergent cryptic leaf colour may have evolved to optimize local camouflage in various visual environments, extending our understanding of colour evolution and intraspecific phenotype diversity in plants.
This work was funded by Ministry of Science and Technology of PRC (National Key Research and Development Program of China, 2017YFC0505200), NSFC (Major Program 31590820 and 31590823 to H.S., and 31670214 to Y.N.), CAS (West Light Foundation to Y.N.) and Yunnan Applied Basic Research Projects (2016FB035 to Y.N.).
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