Deactivation of Plant Defense: Correspondence Between Insect Behavior and Secretory Canal Architecture

Abstract

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Leaf palmate venation and vascular redundancy confer tolerance of hydraulic disruption

“…We found that palmately veined leaves tolerate midrib damage, as can be inflicted generally by insects in several orders, which have converged on this behavior as part of feeding (e.g., 29,30,33,46). All of the study species withstood severing of higher-order veins with little impact.…”

“…We note that there is an alternative, third approach to protecting the leaf-thin, pinnately veined leaves may especially protect their midrib. Indeed, leaves tend to invest midribs with relatively thick cell walls, and sometimes with laticifers and secondary chemistry, which can render the midrib less palatable (46,57); on average, pinnately veined species tend to allocate a greater proportion of their mass to the midrib than palmately veined species (11). Additional investigation is needed of the costs and effectiveness of these alternatives for protecting the leaf.…”

Diet composition and body size in insect herbivores: Why do small species prefer young leaves?

“…Feeding experiments on ex situ leaves can give different results from those performed on live plants, particularly for latex-producing species (Dussourd & Denno, 1991;Farrel et al, 1991). The interruption of latex flow in excised leaves is, however, unlikely to bias the results.…”

Mulberry latex rich in antidiabetic sugar-mimic alkaloids forces dieting on caterpillars

“…atex is widely found among plant species; 12,000-35,000 species have been reported to exude it (1)(2)(3). Plant latex has been suggested to play an important role in plant defense against insect herbivory (1-6) for two reasons: first, latex often contains toxic compounds such as morphine in poppy and cardenolide in milkweeds (2)(3)(4), and, second, many herbivorous insects specialized to feed on latex-containing plants have developed behaviors to avoid consuming latex and to inactivate laticifers by cutting leaf veins or making trenches (1,(4)(5)(6).…”