Antiherbivory defense mechanisms along an environmental gradient in restinga

Abstract

Plant-herbivore interactions have directed the evolution of defense mechanisms in plants, which can vary intraspecifi cally according to environmental quality. Th is study evaluated variation in the production of antiherbivory defenses in plant species distributed along an environmental gradient of restinga. Th e study was performed in Parque Estadual Acaraí, state of Santa Catarina, Brazil. Th ree species of four plant formations with diff erent abiotic conditions were selected for study. Specifi c leaf area; water, nitrogen and carbon content; and presence of phenols, tannins, lignin and alkaloids, were evaluated in leaves of ten plants per species per plant formation. Th e results indicated that Symphyopappus casarettoi possesses Low Nutritional Quality Syndrome, characterized by low specifi c leaf area, presence of secondary metabolites and low nitrogen content. Dodonaea viscosa and Varronia curassavica possess Nutrition and Defense Syndrome, characterized by a balance between nutritional quality (high nitrogen content and lower C:N ratio) and protection (greater thickness of leaves and higher density of trichomes). Th e results did not confi rm the Resource Availability Hypothesis. Th e absence of a pattern in antiherbivory response due to the environmental gradient may indicate that the investment in defense by plants is not unidirectional and that certain morpho-anatomical attributes are typically related to conservation of resources.

Does spatial variation in insect herbivory match variations in plant quality? A meta‐analysis

“…Plant quality for herbivores depends not only on the expression of defensive traits but also on the concentrations of macronutrients (with nitrogen of prime importance), which change with resource availability (Chen et al., 2013; Reich & Oleksyn, 2004). Increased concentrations of essential nutrients in plants generally favour host plant preference and improve herbivore performance (Awmack & Leather, 2002; Mattson, 1980; Scriber & Slansky, 1981), as demonstrated by multiple experiments with herbivores feeding on fertilized plants (Lu et al., 2007; Strengbom et al., 2005) and by observations in edaphic gradients (Ramos et al., 2019; Silva et al., 2017). We therefore expect that, at the geographical spatial scale, herbivory will positively correlate with nutrient concentrations in their host plants (Prediction 3).…”