Grey leaves in an alpine plant: a cryptic colouration to avoid attack?

Area of Science:

• Plant ecology
• Evolutionary biology
• Animal behavior

Background:

• Cryptic coloration is a common anti-predation strategy in animals.
• Its occurrence in plants is hypothesized but lacks rigorous experimental testing.
• Plant coloration can influence herbivory, photosynthesis, and reproductive success.

Purpose of the Study:

• To investigate the cryptic coloration of Corydalis benecincta, an alpine plant with dimorphic leaf colors (grey and green).
• To conduct a cost-benefit analysis of this coloration strategy.
• To determine if grey coloration provides a survival advantage against herbivores.

Main Methods:

• Spectrographic measurements and a butterfly color vision model were used to assess herbivore (Parnassius butterflies) discrimination between grey leaves and scree background.
• Photosynthetic performance and attractiveness to pollinators were compared between grey and green morphs.
• Herbivore damage, survivorship, and female reproductive success were compared between morphs.

Main Results:

• Spectrographic analysis and the vision model indicated difficulty for herbivores to distinguish grey leaves from the background.
• The grey coloration results from a combination of anthocyanins and chlorophylls.
• Both morphs exhibited similar photosynthetic performance and attractiveness to pollinators.
• Grey morphs experienced significantly lower herbivore damage and higher survivorship.

Conclusions:

• Cryptic coloration in grey Corydalis benecincta provides significant benefits by reducing herbivory.
• This strategy involves low investment in anthocyanin synthesis with minimal costs to photosynthesis and mating.
• The evolution of this cryptic coloration is likely driven by selection pressure from visually foraging herbivores.