Ecological Chemistry

Ecological Chemistry a research discipline that deals with understanding complex interactions between or among different organisms in a given ecosystem via chemical signals. Ecological chemistry is evolved by cross-fertilizing two diverse disciplines: ecology and biochemistry. It is the study of chemicals involved in the interactions of living organisms. Ecological chemistry is everywhere. Chemically-mediated interactions between organisms are pervasive at all levels of biological organization, from microbes to humans, across all biomes and habitats.

Chemical signals are a common language used for communication throughout the living world. They are minute in quantity in the cells of living organisms and hence difficult to detect. However, these signals are very target specific. Multiple microorganisms in the ecosystem use various secondary metabolites, such as flavonoids, alkaloids, terpenoids, phenols, etc, for particular communication and interactions. For example, insects use tiny biomolecules called pheromones for mating and communication. Scientists have discovered thousands of pheromones so far. Some of them are used as pheromone traps to control harmful insects in agriculture as a safe, sustainable technology for human health.

Various secondary compounds are important in the complex interactions between animals and plants or plants and microorganisms in the natural environment. Ecological chemistry includes the biochemistry of plant pollination and productivity, defense mechanisms of plants and other organisms, etc. Chemicals that act as messengers between species are commonly termed semiochemicals. ‘Semeon’ means a signal in Greek. Chemical signals or small biomolecules used in interactions between/among organisms, also called eco-chemicals, include pheromones, allomones, kairomones, attractants, and repellants. All insects use semiochemicals that can be used in the biological control of insect pests.

Semiochemicals are biodegradable, target-specific, and environmentally safe. Only target harmful insects are adversely affected by their application. The semiochemicals are relatively non-toxic to the non-targeted organisms. German biochemist Adolf Butenandt was the first to identify such a chemical, bombykol (a chemically well-characterized pheromone secreted by female silkworms to attract mates). Stink bugs and blister beetles secrete defense semiochemicals commonly known as allomones. A familiar example of a kairomone is the lactic acid component of human sweat, which attracts mosquitoes. The smell of flowers is a typical example of environmental chemistry that benefits both the sender and receiver. Allomone production is a common form of defense of plant species against herbivores. Allomones sometimes become kairomones due to an evolutionary arms race. Knowledge of ecological chemistry can be applied to managing pests and pathogens of crop plants in bio-rational ways for sustainable agriculture, environment, and health. [Md. Tofazzal Islam]