## 1 Introduction  
Currently, the investigation of volatile organic compounds (VOCs) in ecology relies upon highly diversified technologies for improving the cogninance of the interactions between the various living beings that utilize these molecules, such as plants, arthropods, fungi, etc. From the distinct known interactions, those associated with insects stand out because they are implicated in several decisive processes in agronomic ecology, such as pollination or even the spread of pests. Because of this, the investigations into VOCs related to insect-insect and insect-plant communications and other interactions have gained importance in pest management, from both chemical and biological points of views [1]. The biologically-generated VOC field is widely developed, and thousands of such compounds have been described. Thus, the investigation into this field requires a holistic approach that is achievedby means of metabolomics, which explores the production and concentrations of secondary metabolites from organisms (i.e., metabolomics) and their metabolomics and correlates these variables to biotic activities or environmental conditions [2]. This is an extensively developed and systematized branch of knowledge, utilizing a broad range of methods that consider metabolite collection as a function of their properties and origin [3], followed by analytical procedures, including molecular biology and instrumental techniques [4], down to compiled data matrix management using mathematical tools [5]. From this integration, it is possible to obtain detailed information about the chemical composition of complex natural extracts to unveil their metabolomics and associate them with particular conditions [6]. Among the VOCs biologically active in insects, metabolomics has addressed several semiochemicals such as pheromones (i.e., the chemical communication language of various insects) [7] and allelochemicals (or allelomones) emitted from other organisms. Pheromones are those substances produced by one animal and excreted to perform a specific effect on another individual from the same species, i.e., mediating intraspecific interactions, while allelochemicals are compounds that mediate interspecific interactions, affecting more of the other species than the producing ones. In this sense, allelochemicals are subclassified depending on the adaptive effect on such species involved within the interaction. Thus, allomones have a neutral effect on the receiver but modify its behavior to benefit the emitter; kairomones are favorable to the receiver but not for the emitter, and synomones benefit both the emitter and the receiver. Both pheromones and allelomones are part of a larger group of compounds called semiochemicals [8]. The plant-derived VOCs are very interesting because their nature and production are related to atmospheric conditions [9] and biotic relationships [10]. Molecules coming both from aerial and underground environments have been profiled with the aim of better recognizing the existing communication between plants and organisms in their surroundings [11; 12]. Otherwise, insect pheromones have been assessed intensely in metabolomics with a chemical ecology scope, achieving the description of diverse related biological functions of insects, such as mating, aggregation, alarm, social hierarchy and defense. In other words, pheromones have been analyzed in an evolutionary, biochemical and structural background [7; 13]. However, metabolomics is not enough for recognizing the explicit effect of a molecule, both singly or in a mixture, on a particular insect, whence such complementary methods as behavioral assays gain relevance for the identification of corresponding responses and allow the inference of biological functions in a defined ecosystem [14]. Therefore, laboratory experiments might be conducted to sample, detect and identify biologically-active VOCs to unravel and explain their roles, prior to understanding the implications in the natural environment and under field conditions [15].