Orchids reduce attachment of herbivorous snails with leaf trichomes

• Published in: PloS one Vol. 18; no. 8; p. e0285731
• Main Authors: Wati, Richa Kusuma, Gravendeel, Barbara, Langelaan, Rob, van Heuven, Bertie Joan, Claessens, Jean, Kleynen, Jacques, Smets, Erik F, de Winter, Anton J, van der Meijden, Arie
• Format: Journal Article
• Language: English
• Published: San Francisco Public Library of Science 18.08.2023
• Subjects: Attachment; Biology and Life Sciences; Botanical research; Capital losses; Diseases and pests; Ecology and Environmental Sciences; Electron microscopy; Engineering and Technology; Environmental aspects; Epidermis; Gastropoda; Greenhouses; Herbivores; Histochemistry; Hypotheses; Leaves; Light microscopy; Lignin; Metabolites; Microscopy; Mollusks; National parks; Optical microscopy; Orchids; Physiological aspects; Plant defenses; Plant-animal interactions; Protective structures; Scanning electron microscopy; Shells; Snails; Transmission electron microscopy; Trichomes; Veins (plant anatomy); Netherlands
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0285731

Protective structures in the epidermis are essential for land plants to defend themselves against herbivores. In this study, we investigated the effect of different types of trichomes of three orchids, Calanthe triplicata, Dendrochilum pallidiflavens and Trichotosia ferox, on attachment of herbivorous land snails, using histochemistry and centrifuge experiments. Size, ornamentation and histochemistry of epicuticular trichomes on the orchid leaves were assessed with light microscopy, scanning electron microscopy and transmission electron microscopy. Total forces needed to detach two differently shaped snail species, Subulina octona and Pleurodonte isabella, were measured using a turntable equipped with a synchronized strobe. Snails were placed in two positions, either perpendicular or parallel to the main veins on the orchid leaves, both on the adaxial (= upper) or abaxial (= lower) side. The results obtained provided three new insights. First, a perpendicular or parallel position of the snails to the main veins did not significantly affect the attachment performance of either species tested. Secondly, snails detached significantly easier on leaf sides covered with a high density of lignin filled epicuticular trichomes. Thirdly, the removal of glandular trichomes did not affect the attachment forces; however, the absence of lignified trichomes increased the attachment of the snails. Our study highlights the importance of studying micro-ornamentation in combination with performance for obtaining a better understanding of the defense mechanisms employed by different species of orchids to deter herbivorous snails.