**1. Introduction**

Photosynthetic organisms are the primary producers; they are essential for correct function of all ecosystems; nevertheless, these organisms are susceptible to be attacked by different herbivores, and they can perform various defensive measures: allocate resources to protect

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themselves from microbes, competitors, ultraviolet (UV) rays, and predators [1], reduce plant tissue quality, and produce chemical and mechanical defenses [2, 3].

Throughout 350 million years, plants and insects have been keeping a close relationship [4] resulting in an efficient defense system in plants that can recognize signals from herbivore and activate the plant immune response against them. To arrest herbivore attack, plants produce specialized metabolites with negative physiological effects against herbivores, such as toxins, deterrent, dissuasive, and/or no nutrition [5].

Metabolites that implicate in defense against herbivores can be modified by biotic and abiotic factors, such as humidity, altitudinal gradient, nutrient availability, herbivores diversity, etc., [6]. Then, we asked: at distinct environments, are plant defense mechanisms the same? If they are different, are there some recognizable patterns at separate environments?

To answer, we select three very distinct ecosystems to compare plant defense traits: the first great difference is between aquatic and terrestrial environments, and the latter we divide in tempered and tropical forest. The objective is recognizing the ecological and evolutionary diversification of plant defense traits at distinct environments.
