View source for Chemical ecology

{{short description|Study of chemically-mediated interactions between living organisms}}
'''Chemical ecology''' is the study of chemically mediated interactions between living organisms, and the effects of those interactions on the demography, behavior and ultimately evolution of the organisms involved. It is thus a vast and highly interdisciplinary field.<ref>{{Cite journal |last=Bunin |first=Barry A. |date=December 1996 |title=<i>Chemical Ecology: The Chemistry of Biotic Interaction.</i>Thomas Eisner , Jerrold Meinwald |url=http://dx.doi.org/10.1086/419565 |journal=The Quarterly Review of Biology |volume=71 |issue=4 |pages=562 |doi=10.1086/419565 |issn=0033-5770}}</ref><ref name="Dyer et al">{{Cite journal|last1=Dyer|first1=Lee A.|last2=Philbin|first2=Casey S.|last3=Ochsenrider|first3=Kaitlin M.|last4=Richards|first4=Lora A.|last5=Massad|first5=Tara J.|last6=Smilanich|first6=Angela M.|last7=Forister|first7=Matthew L.|last8=Parchman|first8=Thomas L.|last9=Galland|first9=Lanie M.|date=2018-05-25|title=Modern approaches to study plant–insect interactions in chemical ecology|journal=Nature Reviews Chemistry|volume=2|issue=6|pages=50–64|doi=10.1038/s41570-018-0009-7|s2cid=49362070|issn=2397-3358}}</ref> Chemical ecologists seek to identify the specific molecules (i.e. [[semiochemical]]s) that function as signals mediating [[community (ecology)|community]] or [[ecosystem]] processes and to understand the evolution of these signals. The substances that serve in such roles are typically small, readily-diffusible [[organic compound|organic molecules]], but can also include larger molecules and small peptides.<ref>{{cite journal |journal=Journal of Chemical Education |volume=60 |issue=7 |year=1983 |title=Chemical Ecology: Chemical Communication in Nature |author1=Wood William F. |doi=10.1021/ed060p531|pages=531–539 }}</ref>

In practice, chemical ecology relies extensively on [[chromatography|chromatographic techniques]], such as [[thin-layer chromatography]], [[high performance liquid chromatography]], and [[gas chromatography]], to isolate and identify bioactive metabolites. To identify molecules with the sought-after activity, chemical ecologists often make use of [[bioassay]]-guided [[fractionation]]. Today, chemical ecologists also incorporate genetic and genomic techniques to understand the [[biosynthesis|biosynthetic]] and [[signal transduction]] pathways underlying chemically mediated interactions.<ref name="Meinwald Eisner pp. 4539–4540">{{cite journal | last1=Meinwald | first1=J. | last2=Eisner | first2=T. | title=Chemical ecology in retrospect and prospect | journal=Proceedings of the National Academy of Sciences | volume=105 | issue=12 | date=19 March 2008 | issn=0027-8424 | doi=10.1073/pnas.0800649105 | pmid=18353981 | pages=4539–4540| pmc=2290750 | doi-access=free }}</ref>

== Plant chemical ecology ==
[[File:Monarch_Butterfly_Danaus_plexippus_Vertical_Caterpillar_2000px.jpg|thumb|[[Monarch butterfly]] caterpillar on [[Asclepias|milkweed]] plant.]]
Plant chemical ecology focuses on the role of chemical cues and signals in mediating interactions of plants with their biotic environment (e.g. microorganisms, phytophagous insects, and pollinators).<ref>{{Cite journal |last=Fraenkel |first=Gottfried S. |date=1959-05-29 |title=The Raison d'Être of Secondary Plant Substances: These odd chemicals arose as a means of protecting plants from insects and now guide insects to food |url=https://www.science.org/doi/10.1126/science.129.3361.1466 |journal=Science |language=en |volume=129 |issue=3361 |pages=1466–1470 |doi=10.1126/science.129.3361.1466 |issn=0036-8075}}</ref>

=== Plant-insect interactions ===
{{further|Plant defense against herbivory}}
[[File:Chlaenius Plate 10 Eisner et al 1963.png|alt=left|thumb|Series from a study by [[Thomas Eisner|Eisner]] and colleagues investigating [[Chemical defense|defensive]] spray in [[bombardier beetle]]s. The paper is specially treated to have a [[color reaction]] with the spray, which is normally clear.]]

The chemical ecology of plant-insect interaction is a significant subfield of chemical ecology.<ref name="Dyer et al" /><ref name="Mithfer">{{Citation|last1=Mithfer|first1=Axel|chapter=Chemical Ecology of Plant–Insect Interactions|pages=261–291|publisher=Wiley-Blackwell|language=en|doi=10.1002/9781444301441.ch9|isbn=978-1-4443-0144-1|last2=Boland|first2=Wilhelm|last3=Maffei|first3=Massimo E.|title=Molecular Aspects of Plant Disease Resistance|year=2008}}</ref><ref name="Dyer 50–64">{{Cite journal|last1=Dyer|first1=Lee A.|last2=Philbin|first2=Casey S.|last3=Ochsenrider|first3=Kaitlin M.|last4=Richards|first4=Lora A.|last5=Massad|first5=Tara J.|last6=Smilanich|first6=Angela M.|last7=Forister|first7=Matthew L.|last8=Parchman|first8=Thomas L.|last9=Galland|first9=Lanie M.|date=2018-05-25|title=Modern approaches to study plant–insect interactions in chemical ecology|journal=Nature Reviews Chemistry|language=En|volume=2|issue=6|pages=50–64|doi=10.1038/s41570-018-0009-7|s2cid=49362070|issn=2397-3358}}</ref> In particular, plants and insects are often involved in a chemical [[evolutionary arms race]]. As plants develop chemical defenses to herbivory, insects which feed on them evolve immunity to these poisons, and in some cases, repurpose these poisons for their own [[chemical defense]] against predators. For example, caterpillars of the [[monarch butterfly]] sequester [[cardenolide]] toxins from their [[Asclepias|milkweed]] host-plants and are able to use them as an anti-predator defense.<ref>{{Cite journal |last1=Brower |first1=L P |last2=van Brower |first2=J |last3=Corvino |first3=J M |date=April 1967 |title=Plant poisons in a terrestrial food chain. |journal=Proceedings of the National Academy of Sciences |language=en |volume=57 |issue=4 |pages=893–898 |doi=10.1073/pnas.57.4.893 |doi-access=free |issn=0027-8424 |pmc=224631 |pmid=5231352}}</ref> Whereas most insects are killed by cardenolides, which are potent inhibitors of the [[Na+/K+-ATPase]], monarchs have evolved resistance to the toxin over their long evolutionary history with milkweeds. Other examples of sequestration include the tobacco hornworm ''[[Manduca sexta]]'',  which use [[nicotine]] sequestered from [[Nicotiana|tobacco plant]]s in predator defense;<ref name="Mithfer" /> and the [[Utetheisa ornatrix|bella moth]], which secretes a [[quinone]]-containing froth to deter predators obtained from feeding on ''[[Crotalaria]]'' plants as a caterpillar.

Chemical ecologists also study chemical interactions involved in [[Plant defense against herbivory#Indirect defenses|indirect defenses of plants]], such as the attraction of [[predator]]s and [[parasitoid]]s through herbivore-induced [[volatile organic compounds]] (VOCs).

=== Plant-microbe interactions ===
{{further|Plant disease resistance|Plant use of endophytic fungi in defense|Phytoalexin}}
Plant interactions with [[microorganism]]s are also mediated by chemistry. Both constitutive and induced secondary metabolites (specialized metabolites in modern terminology) are involved in plant defense against pathogens and chemical signals are also important in the establishment and maintenance of resource [[Mutualism (biology)|mutualisms]]. For example, both [[rhizobia]] and [[mycorrhiza]]e depend on chemical signals, such as [[strigolactone]]s and [[flavanoid]]s exuded from plant roots, in order to find a suitable host.

For microbes to gain access to the plant, they must be able to penetrate the layer of wax that forms a [[hydrophobic]] barrier on the plant's surface. Many plant-pathogenic microbes secrete enzymes that break down these cuticular waxes.<ref name="Müller">{{Cite journal|last1=Müller|first1=Caroline|last2=Riederer|first2=Markus|title=Plant Surface Properties in Chemical Ecology|journal=Journal of Chemical Ecology|language=en|volume=31|issue=11|pages=2621–2651|doi=10.1007/s10886-005-7617-7|pmid=16273432|issn=0098-0331|year=2005|s2cid=33373155}}</ref> Mutualistic microbes on the other hand may be granted access. For example, rhizobia secrete [[Nod factor]]s that trigger the formation of an infection thread in receptive plants. The rhizobial symbionts can then travel through this infection thread to gain entrance to root cells.

Mycorrhizae and other fungal endophytes may also benefit their host plants by producing [[antibiotic]]s or other [[secondary metabolite]]s/ specialized metabolites that ward off harmful fungi, bacteria and herbivores in the soil.<ref>{{Cite journal |doi = 10.1039/C4NP00166D|pmid = 26038303|title = Chemical ecology of fungi|journal = Natural Product Reports|volume = 32|issue = 7|pages = 971–993|year = 2015|last1 = Spiteller|first1 = Peter}}</ref> Some [[entomopathogenic fungus|entomopathogenic fungi]] can also form endophytic relationships with plants and may even transfer nitrogen directly to plants from insects they consume in the surrounding soil.<ref>Behie, S. W., P. M. Zelisko, and M. J. Bidochka. 2012. Endophytic Insect-Parasitic Fungi Translocate Nitrogen Directly from Insects to Plants. Science 336:1576–1577.</ref>

=== Plant-plant interactions ===
==== Allelopathy ====
{{Main|Allelopathy}}
Many plants produce secondary/ specialized metabolites (known as [[allelochemical]]s) that can inhibit the growth of neighboring plants. Many examples of allelopathic [[Competition (biology)|competition]] have been controversial due to the difficulty of positively demonstrating a causal link between allelopathic substances and plant performance under natural conditions,<ref>Duke, S. O. 2010. Allelopathy: Current status of research and future of the discipline: A commentary.</ref> but it is widely accepted that phytochemicals are involved in competitive interactions between plants. One of the clearest examples of allelopathy is the production of [[juglone]] by [[Juglans|walnut trees]], whose strong competitive effects on neighboring plants were recognized in the ancient world as early as 36 BC.<ref>Willis, R. J. 2000. Juglans spp., juglone and allelopathy. Allelopathy Journal 7:1–55.</ref>

==== Plant-plant communication ====
{{Main|Plant communication}}
Plants communicate with each other through both airborne and below-ground chemical cues. For example, when damaged by an herbivore, many plants emit an altered bouquet of volatile organic compounds (VOCs). Various C6 fatty acids and alcohols (sometimes known as [[green leaf volatile]]s) are often emitted from damaged leaves, since they are break-down products of plant cell membranes. These compounds (familiar to many as the smell of freshly mown grass) can be perceived by neighboring plants where they may trigger the induction of plant defenses.<ref>{{Cite journal| doi = 10.1093/pcp/pcp030| issn = 0032-0781| volume = 50| issue = 5| pages = 911–923| last1 = Arimura| first1 = Gen-ichiro| last2 = Matsui| first2 = Kenji| last3 = Takabayashi| first3 = Junji| title = Chemical and Molecular Ecology of Herbivore-Induced Plant Volatiles: Proximate Factors and Their Ultimate Functions| journal = Plant and Cell Physiology| access-date = 2017-10-11| date = 2009-05-01| pmid = 19246460| url = https://academic.oup.com/pcp/article/50/5/911/1838345/Chemical-and-Molecular-Ecology-of-Herbivore| doi-access = free}}</ref>  It is debated to what extent this communication reflects a history of active selection due to mutual benefit as opposed to "eavesdropping" on cues unintentionally emitted by neighboring plants.<ref>Heil, M., and R. Karban. 2010. Explaining evolution of plant communication by airborne signals. Trends in Ecology & Evolution 25:137–144.</ref>

== Marine chemical ecology ==

=== Defense ===
[[File:Vi - Zoanthus sociatus - 2.jpg|thumb|right|''Zoanthus sociatus'' produces palytoxin]]

Many marine organisms use chemical defenses to deter predators. For example, some [[crustacean]]s and [[mesograzer]]s, such as the ''[[Pseudamphithoides incurvaria]]'', use toxic [[algae]] and seaweeds as a shield against predation by covering their bodies in these plants. These plants produce [[Phycotoxin|phycotoxins]], [[diterpene]]s such as pachydictyol-A and dictyol-E, which have been shown to deter predators.{{citation needed|date=October 2022}} Other marine organisms produce chemicals endogenously to defend themselves. For example, the finless sole (''[[Pardachirus marmoratus]]'') produces a toxin that paralyzes the jaws of would-be predators. Many [[Zoantharia|zoanthids]] produce potent toxins, such as [[palytoxin]], which is one of the most poisonous known substances. Some species of these zooanthids are very brightly colored, which may be indicative of [[aposematism|aposematic]] defense.<ref>{{Cite journal|last1=Bakus|first1=Gerald J.|last2=Targett|first2=Nancy M.|last3=Schulte|first3=Bruce|title=Chemical ecology of marine organisms: An overview|journal=Journal of Chemical Ecology|language=en|volume=12|issue=5|pages=951–987|doi=10.1007/bf01638991|pmid=24307042|issn=0098-0331|year=1986|s2cid=34594704}}</ref>

=== Reproduction ===
Many marine organisms use [[Pheromone|pheromones]] as chemical cues alerting possible mates that they are ready to reproduce.<ref>{{Cite web |title=CH105: Chapter 6 - A Brief History of Natural Products and Organic Chemistry |url=https://wou.edu/chemistry/courses/online-chemistry-textbooks/ch105-consumer-chemistry/ch105-chapter-6-hydrocarbons/ |access-date=2024-09-15 |website=Chemistry |language=en-US}}</ref> For example, male [[sea lamprey]]s attract ovulating females by emitting a bile that can be detected many meters downstream.<ref>{{Cite journal| doi = 10.1126/science.1067797| issn = 0036-8075 | volume = 296| issue = 5565| pages = 138–141| last1 = Li| first1 = Weiming| last2 = Scott| first2 = Alexander P.| last3 = Siefkes| first3 = Michael J.| last4 = Yan| first4 = Honggao| last5 = Liu| first5 = Qin| last6 = Yun| first6 = Sang-Seon| last7 = Gage| first7 = Douglas A.| title = Bile Acid Secreted by Male Sea Lamprey That Acts as a Sex Pheromone| journal = Science| access-date = 2020-10-19| date = 2002-04-05| url = https://www.science.org/doi/10.1126/science.1067797| pmid = 11935026| bibcode = 2002Sci...296..138L| s2cid = 1688247}}</ref> Other processes can be more complex, such as the mating habits of crabs. Due to the fact that female crabs can only mate during a short period after [[Moulting|moults]] from her shell, female crabs produces pheromones before she begins to moult in order to attract a mate. Male crabs will detect these pheromones and defend their potential mate until she has finished molted. However, due to the cannibalistic tendencies of crabs, the female produces an additional pheromone to suppresses cannibalistic instincts in her male guardian. These pheromones are very potent—so much so that they can induce male crabs to try to copulate with rocks or sponges that have been coated in pheromone by researchers.<ref name="Mark E. Hay">{{Cite journal|last=Hay|first=Mark E.|date=2009|title=Marine Chemical Ecology: Chemical Signals and Cues Structure Marine Populations, Communities, and Ecosystems|journal=Annual Review of Marine Science|volume=1|pages=193–212|issn=1941-1405|pmc=3380104|pmid=21141035|doi=10.1146/annurev.marine.010908.163708|bibcode=2009ARMS....1..193H}}</ref>

=== Dominance ===
[[File:American lobster, Homarus americanus in Newfoundland, Canada (20996211958).jpg|thumb|right|American lobster (''[[Homarus americanus]]'')]]
[[Dominance (ethology)|Dominance]] among crustaceans is also mediated through chemical cues. When crustaceans fight to determine dominance they urinate into the water. Later, if they meet again, both individuals can recognize each other by pheromones contained in their urine, allowing them to avoid a fight, if dominance has already been established. When a lobster encounters the urine of another individual, it will act differently according to the perceived status of the urinator (e.g. more submissively when exposed to the urine of a more dominant crab, or more boldly when exposed to the urine of a subdominant individual). When individuals are unable to communicate through urine, fights may be longer and more unpredictable.<ref name="Mark E. Hay" />

== Applications of chemical ecology ==

[[File:Feromon trap lymantria monacha 2 beentree.jpg|thumb|Pheromone trap used to catch the pest ''[[Lymantria monacha]]''.]]

=== Pest control ===
Chemical ecology has been utilized in the development of sustainable [[pest control]] strategies. Semiochemicals (especially insect [[sex pheromones]]) are widely used in [[integrated pest management]] for surveillance, [[pheromone trap|trapping]] and [[mating disruption]] of pest insects.<ref name=Witzgall2010>Witzgall, P., P. Kirsch, and A. Cork. 2010. Sex Pheromones and Their Impact on Pest Management. J Chem Ecol 36:80–100.</ref> Unlike conventional insecticides, pheromone-based methods of pest control are generally species-specific, non-toxic and extremely potent. In forestry, mass trapping has been used successfully to reduce tree mortality from [[bark beetle]] infestations in spruce and pine forests and from [[Rhynchophorus|palm weevils]] in palm plantations.<ref name=Witzgall2010/> In an aquatic system, a sex pheromone from the invasive [[sea lamprey]] has been registered by the United States Environmental Protection Agency for deployment in traps.<ref>KleinJan. 20, K., 2016, and 1:30 Pm. 2016. So long suckers! Sex pheromone may combat destructive lampreys.</ref> A strategy has been developed in Kenya to protect cattle from [[sleeping sickness|trypanosomiasis]] spread by [[Tsetse flies|Tsetse fly]] by applying a mixture of repellent odors derived from a non-host animal, the [[waterbuck]].<ref>Saini, R. K., B. O. Orindi, N. Mbahin, J. A. Andoke, P. N. Muasa, D. M. Mbuvi, C. M. Muya, J. A. Pickett, and C. W. Borgemeister. 2017. Protecting cows in small holder farms in East Africa from tsetse flies by mimicking the odor profile of a non-host bovid. PLOS Neglected Tropical Diseases 11:e0005977. Public Library of Science.</ref>

The successful [[push-pull agricultural pest management]] system makes use of chemical cues from intercropped plants to sustainably increase agricultural yields. The efficacy of push-pull agriculture relies on multiple forms of chemical communication. Though the push-pull technique was invented as a strategy to control [[Stemborer|stem-boring]] moths, such as ''[[Chilo partellus]]'', through the manipulation of volatile [[kairomone|host-finding cues]], it was later discovered that allelopathic substances exuded by the roots of [[Desmodium|''Desmodium spp.'']] also contribute to the suppression of the damaging parasitic weed, ''[[Striga]]''.<ref>Khan, Z., C. Midega, J. Pittchar, J. Pickett, and T. Bruce. 2011. Push—pull technology: a conservation agriculture approach for integrated management of insect pests, weeds and [[soil health]] in Africa. International Journal of Agricultural Sustainability 9:162–170. Taylor & Francis.</ref>

=== Drug development and biochemistry discoveries ===
{{Main|Natural_product#Medical uses}}
A large proportion of commercial drugs (e.g. [[aspirin]], [[ivermectin]], [[cyclosporin]], [[taxol]]) are derived from natural products that evolved due to their involvement in ecological interactions. While it has been proposed that the study of natural history could contribute to the discovery of new [[lead compound|drug leads]], most drugs derived from natural products were not discovered due to prior knowledge of their ecological functions.<ref>Caporale, L. H. 1995. Chemical ecology: a view from the pharmaceutical industry. Proceedings of the National Academy of Sciences 92:75–82.</ref> However, many fundamental biological discoveries have been facilitated by the study of plant toxins. For example, the characterization of the [[nicotinic acetylcholine receptor]], the first [[neurotransmitter]] receptor to be identified, ensued from investigations into the mechanisms of action of [[curare]] and [[nicotine]]. Similarly, the [[muscarinic acetylcholine receptor]] takes its name from the fungal toxin [[muscarine]].<ref>Martindale, R., and R. A. J. Lester. 2014. On the Discovery of the Nicotinic Acetylcholine Receptor Channel. Pp. 1–16 in R. A. J. Lester, ed. Nicotinic Receptors. Springer, New York, NY.</ref>

== History of chemical ecology ==
=== After 1950 ===
[[File:CSIRO ScienceImage 10746 An adult silkworm moth.jpg|thumb|right|Silk moth (''Bombyx mori'')]]
In 1959, [[Adolf Butenandt]] identified the first intraspecific chemical signal ([[bombykol]]) from the silk moth, ''[[Bombyx mori]]'', with material obtained by grinding up 500,000 moths.<ref>Wyatt, T. D. 2009. Fifty years of pheromones. Nature 457:262–263. Nature Publishing Group.</ref> The same year, Karlson and Lüscher proposed the term 'pheromone' to describe this type of signal.<ref name=Bergstrom2007>Bergström, G. 2007. Chemical ecology = chemistry + ecology! Pure and Applied Chemistry 79:2305–2323.</ref> Also in 1959, Gottfried S. Fraenkel also published his landmark paper, "The Raison d'être of Secondary Plant Substances", arguing that plant secondary/ specialized metabolites are not metabolic waste products, but actually evolved to protect plants from consumers.<ref>Fraenkel, G. S. 1959. The Raison d’Être of Secondary Plant Substances: These odd chemicals arose as a means of protecting plants from insects and now guide insects to food. Science 129:1466–1470. American Association for the Advancement of Science.</ref> Together, these papers marked the beginning of modern chemical ecology. In 1964, [[Paul R. Ehrlich]] and [[Peter H. Raven]] coauthored a paper proposing their influential theory of [[escape and radiate coevolution]], which suggested that an evolutionary "arms-race" between plants and insects can explain the extreme diversification of plants and insects.<ref>Ehrlich, P. R., and P. H. Raven. 1964. Butterflies and Plants: A Study in Coevolution. Evolution 18:586–608.</ref> The idea that plant metabolites could not only contribute to the survival of individual plants, but could also influence broad [[macroevolution]]ary patterns, would turn out to be highly influential. However, [[:hu:Jermy_Tibor|Tibor Jermy]] questioned the view of an evolutionary arms race between plants and their insect herbivores and proposed that the evolution of phytophagous insects followed and follows that of plants without major evolutionary feedback, i.e. without affecting plant evolution.<ref>{{Cite journal |last=Jermy |first=Tibor |date=1984 |title=Evolution of insect/host plant relationships |url=https://www.journals.uchicago.edu/doi/abs/10.1086/284302 |journal=The American Naturalist |volume=124 |issue=5 |pages=609–630|doi=10.1086/284302 }}</ref> He coined the term sequential evolution to describe plant-insect macroevolutionary patterns, which emphasizes that selection pressure exerted by insect attack on plants is weak or lacking.<ref>{{Cite journal |last=Jermy |first=Tibor |date=1993 |title=Evolution of insect-plant relationships - a devil's advocate approach |url=https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1570-7458.1993.tb00686.x |journal=Entomologia Experimentalis et Applicata |volume=66 |issue=1 |pages=3–12|doi=10.1111/j.1570-7458.1993.tb00686.x }}</ref>

In the 1960s and 1970s, a number of plant biologists, ecologists, and entomologists expanded this line of research on the ecological roles of plant secondary/ specialized metabolites. During this period, [[Thomas Eisner]] and his close collaborator [[Jerrold Meinwald]] published a series seminal papers on chemical defenses in plants and insects.<ref name="Eisner pp. 1318–1320">{{cite journal | last=Eisner | first=T. | title=Catnip: Its Raison d'Etre | journal=Science | volume=146 | issue=3649 | date=4 December 1964 | issn=0036-8075 | doi=10.1126/science.146.3649.1318 | pages=1318–1320| pmid=14207462 | bibcode=1964Sci...146.1318E | s2cid=11282193 }}</ref><ref>{{Cite journal| issn = 0036-8075| volume = 153| issue = 3742| pages = 1341–1350| last1 = Eisner| first1 = Thomas| last2 = Meinwald| first2 = Jerrold| title = Defensive Secretions of Arthropods| journal = Science| access-date = 2020-10-25| date = 1966| doi = 10.1126/science.153.3742.1341| url = https://www.jstor.org/stable/1719969| jstor = 1719969| pmid = 17814381| bibcode = 1966Sci...153.1341E}}</ref> A number of other scientists at Cornell were also working on topics related to chemical ecology during this period, including Paul Feeny, [[Wendell L. Roelofs]], [[Robert Whittaker (ecologist)|Robert Whittaker]] and [[Richard B. Root]]. In 1968, the first course in chemical ecology was initiated at Cornell.<ref>{{Cite web|url=http://www.chemicalecology.cornell.edu/historyandintro.html|title = History and Introduction}}</ref> In 1970, Eisner, Whittaker and the ant biologist William L. Brown, Jr. coined the terms [[allomone]] (to describe semiochemicals that benefit the emitter, but not the receiver) and [[kairomone]] (to describe semiochemicals that benefit the receiver only).<ref>Brown, W. L., T. Eisner, and R. H. Whittaker. 1970. Allomones and Kairomones: Transspecific Chemical Messengers. BioScience 20:21–21. Oxford Academic.</ref> Whittaker and Feeny published an influential review paper in ''Science'' the following year, summarizing the recent research on the ecological roles of chemical defenses in a wide variety of plants and animals and likely introducing Whittaker's new taxonomy of semiochemicals to a broader scientific audience.<ref>Whittaker, R. H., and P. P. Feeny. 1971. Allelochemics: Chemical Interactions between Species. Science 171:757–770. American Association for the Advancement of Science.</ref> Around this time, [[Lincoln Brower]] also published a series of important ecological studies on monarch sequestration of cardenolides. Brower has been credited with popularizing the term "ecological chemistry" which appeared in the title of a paper he published in ''Science'' in 1968<ref>Brower, L. P., W. N. Ryerson, L. L. Coppinger, and S. C. Glazier. 1968. Ecological Chemistry and the Palatability Spectrum. Science 161:1349–1350. American Association for the Advancement of Science.</ref> and again the following year in an article he wrote for ''[[Scientific American]]'', where the term also appeared on the front cover under an image of a giant bluejay towering over two monarch butterflies.<ref name=Bergstrom2007/><ref>{{Cite web|url=https://monarchwatch.org/blog/2018/08/02/dr-lincoln-brower/|title = Dr. Lincoln Brower|date = 3 August 2018}}</ref>

The specialized ''[[Journal of Chemical Ecology]]'' was established in 1975, and the Journal ''Chemoecology'' was founded in 1990. In 1984, the International Society of Chemical Ecology was established and in 1996, the [[Max Planck Institute of Chemical Ecology]] was founded in Jena, Germany.<ref name=Bergstrom2007/>

==See also==
* [[Chemical defense]]
* [[Semiochemical]]
* [[:Category:Chemical ecologists|Chemical ecologists]]
* [[May R. Berenbaum]]
* [[Lincoln Brower]]
* [[Thomas Eisner]]
* [[Jerrold Meinwald]]
* [[Wendell L. Roelofs]]
* [[Escape and radiate coevolution]]

== References ==
{{reflist|2}}

==Further reading==
{{refbegin|2}}
* {{cite journal | author = Berenbaum MR & Robinson GE  | year = 2003 | title = Chemical Communication in a Post-Genomic World [Colloquium introductory article] | journal = Proceedings of the National Academy of Sciences of the United States of America | volume=100 | issue=Suppl 2; November 25 | page =14513 | doi = 10.1073/pnas.2335883100 | pmid = 14595008 | bibcode =2003PNAS..10014513B | pmc =304109 | doi-access = free }}   
*{{Cite journal| doi = 10.1351/pac200779122305| issn = 1365-3075| volume = 79| issue = 12| pages = 2305–2323| last = Bergström| first = Gunnar| title = Chemical ecology = chemistry + ecology!| journal = Pure and Applied Chemistry| date = 2007-01-01| s2cid = 86385084| doi-access = free}}
* {{cite book |author1=Wajnberg, Eric |author2=Colazza, Stefano  | year = 2013 | title=Chemical Ecology of Insect Parasitoids | publisher= Blackwell | isbn =978-1-118-40952-7}}
* {{Cite journal| doi = 10.1039/B005311M| volume = 18| issue = 4| pages = 361–379| last = B. Harborne| first = Jeffrey| title = Twenty-five years of chemical ecology| journal = Natural Product Reports| accessdate = 2021-06-13| date = 2001| pmid = 11548048| url = https://pubs.rsc.org/en/content/articlelanding/2001/np/b005311m}}
* {{Cite journal| doi = 10.1073/pnas.0709231105| issn = 0027-8424| volume = 105| issue = 12| pages = 4541–4546| last = Hartmann| first = Thomas| title = The lost origin of chemical ecology in the late 19th century| journal = Proceedings of the National Academy of Sciences of the United States of America| date = 2008-03-25| pmid = 18218780| pmc = 2290813| doi-access = free}}
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{{refend}}

==External links==
{{Commons category}}
* [http://www.chemecol.org International Society of Chemical Ecology]

{{Modelling ecosystems}}
{{Branches of ecology}}
{{Authority control}}

[[Category:Chemical ecology| ]]