Do calcium oxalate crystals protect against herbivory?
- 27 May 2021
- journal article
- research article
- Published by Springer Science and Business Media LLC in The Science of Nature
- Vol. 108 (3), 1-7
- https://doi.org/10.1007/s00114-021-01735-z
Abstract
Calcium oxalate (CaOx) crystals have challenged human curiosity since the advent of microscopy. These crystals are linked to the control of calcium levels in plant cells, but they have also been attributed several other functions, including protection against herbivory. However, the protection offered by CaOx crystals against herbivory may be overstated, as claims have been mainly based on their shapes and hard and indigestible nature rather than on experimental evidence. I contend that it is improbable that a constitutive defense, present since very early in the evolution of plants, has not been superseded by herbivores, especially insects. Here, I present arguments and evidence that suggest that these crystals have low efficiency in protecting plants against herbivores. First, I argue that insects with chewing mouthparts possess a semipermeable structure that protects their midgut, minimizing damage from crystals. Second, the action of CaOx crystals is purely mechanical and similar to other inert materials such as sand. Therefore, CaOx crystals only provide effective protection from herbivory in very particular cases and should not be considered an effective defense without supporting experimental evidence.Keywords
Funding Information
- Conselho Nacional de Desenvolvimento Científico e Tecnológico (305638/2018‒1)
This publication has 42 references indexed in Scilit:
- Medicago truncatula‐derived calcium oxalate crystals have a negative impact on chewing insect performance via their physical propertiesEntomologia Experimentalis et Applicata, 2009
- Expression of Poplar Chitinase in Tomato Leads to Inhibition of Development in Colorado Potato BeetleBiotechnology Letters, 2006
- Medicago truncatula Mutants Demonstrate the Role of Plant Calcium Oxalate Crystals as an Effective Defense against Chewing InsectsPlant Physiology, 2006
- Effects of Kaolin-Based Particle Film Application on Boll Weevil (Coleoptera: Curculionidae) Injury to CottonJournal of Economic Entomology, 2002
- Calcium oxalate crystals in leaves of Pancratiumsickenbergeri: constitutive or induced defence?Functional Ecology, 2002
- Co-evolution and plant resistance to natural enemiesNature, 2001
- Molecular structure of the peritrophic membrane (PM): Identification of potential PM target sites for insect controlArchives of Insect Biochemistry and Physiology, 2001
- Calcium Oxalate Crystals: The Irritant Factor in KiwifruitJournal of Food Science, 1990
- Calcium oxalate crystals in plantsThe Botanical Review, 1980
- Electric Conductivity of Red Blood Corpuscles Using High Frequency Alternating CurrentsScience, 1924