Kairomones are a subtle yet potent force in nature's complex web. For example, human kairomones can significantly influence mosquito behavior. When humans exhale, they release carbon dioxide, L-(+)-lactic acid, and ammonia, unwittingly signaling their presence to mosquitoes. This chemical signal is a dinner bell for these insects, guiding them to their next blood meal. This interaction, while advantageous for the mosquito, is a clear disadvantage for humans, particularly considering the role mosquitoes play in transmitting diseases.
The study of human kairomones opens a window into understanding and potentially controlling mosquito populations. A recent study highlighted the potential of geraniol in reducing mosquito attraction by 69-78% to a mixture of key human kairomones like carbon dioxide, L-(+)-lactic acid, and ammonia.
This chemical dialogue extends beyond animals to the plant kingdom. Plants, though lacking a nervous system or traditional senses, have their own form of communication, often mediated by chemicals. For instance, when a plant is under attack, it can release volatile compounds to attract predators of the herbivores harming it. Interestingly, these chemicals can also alert nearby plants of potential danger.
A case study involving sagebrush and wild tobacco plants provides insight into this phenomenon. When sagebrush is damaged, it releases methyl jasmonate, a volatile compound that nearby tobacco plants detect, triggering an increase in their production of defensive agents. This chemical warning system, however, seems to have a very limited range.
The study of chemical communication in nature, whether between humans and mosquitoes or among plants, is an ongoing journey of discovery. It reveals the intricate and often hidden ways in which life on Earth interacts and adapts. As research continues, we may find more innovative ways to apply this knowledge, from controlling pests to understanding ecosystem dynamics.
Chemical communication remains a fascinating and largely uncharted frontier, offering a glimpse into the sophisticated and silent language of nature.
REFERENCES
Coutinho-Abreu IV, Jamshidi O, Raban R, Atabakhsh K, Merriman JA, Akbari OS. Identification of human skin microbiome odorants that manipulate mosquito landing behavior. Sci Rep. 2024 Jan 18;14(1):1631. doi: 10.1038/s41598-023-50182-5. PMID: 38238397; PMCID: PMC10796395.
Karban R, Shiojiri K, Huntzinger M, McCall AC. Damage-induced resistance in sagebrush: volatiles are key to intra- and interplant communication. Ecology. 2006 Apr;87(4):922-30. doi: 10.1890/0012-9658(2006)87[922:drisva]2.0.co;2. PMID: 16676536.
Chemical & Engineering News: Critter Chemistry - Plants to Bugs: Buzz Off! (acs.org) by Sophie Wilkinson, Chemical & Engineering News, American Chemical Society
The short film "Descendants" provides a creative exploration of nature's interconnectedness: http://vimeo.com/8642276
https://entomology.ucdavis.edu/people/richard-karban
https://swissplantscienceweb.unibas.ch/en/farmer/
https://www.ice.mpg.de/person/111845
