Chemical ecology
[15] 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.
For example, both rhizobia and mycorrhizae depend on chemical signals, such as strigolactones and flavanoids exuded from plant roots, in order to find a suitable host.
Mycorrhizae and other fungal endophytes may also benefit their host plants by producing antibiotics or other secondary metabolites/ specialized metabolites that ward off harmful fungi, bacteria and herbivores in the soil.
One of the clearest examples of allelopathy is the production of juglone by walnut trees, whose strong competitive effects on neighboring plants were recognized in the ancient world as early as 36 BC.
Various C6 fatty acids and alcohols (sometimes known as green leaf volatiles) are often emitted from damaged leaves, since they are break-down products of plant cell membranes.
[25] 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.
[26] Further information: predator-prey arms race Reptiles interaction also contribute to chemical ecology via bioaccumulation or neutralization of toxic compounds.
[30] Horned lizards evolution has shown the blood contains a factor that metabolizes toxins produced by harvester ants.
[32][33][34] These applications vary from prevention of internal and external parasites or pathogens, decrease likelihood of infection, increase reproductive function, reducing inflammation, social cues, and more.
[32][34] Red-fronted lemurs (Eulemur ruffrons) have evolved two pathways, preventive measure for avoiding bioaccumulation, allowing for the modification of 2-methyl-1,4-benzoquinone and 2-methoxy-3-methyl-1,4-benzoquinone a secretion of Spirostreptidae millipedes shown to inhibit certain bacterial species.
[33] Red-fronted lemurs have also been observed in rubbing the secretion on their fur similar to capuchins, this action uses benzoquinone compounds as repellent for various insects such as ticks and mosquitoes.
For example, some crustaceans and mesograzers, such as the Pseudamphithoides incurvaria, use toxic algae and seaweeds as a shield against predation by covering their bodies in these plants.
[40] There is also development of blue crab defense, which utilizes sensory organs for detecting chemical changes in the water to alert them of predators.
[42] For example, male sea lampreys attract ovulating females by emitting a bile that can be detected many meters downstream.
[44] Furthermore, compound structure plays a key role, e.g. crab pheromones are specialized to travel in aquatic vs terrestrial environments.
[46] Unlike conventional insecticides, pheromone-based methods of pest control are generally species-specific, non-toxic and extremely potent.
[46] 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.
[47] A strategy has been developed in Kenya to protect cattle from trypanosomiasis spread by Tsetse fly by applying a mixture of repellent odors derived from a non-host animal, the waterbuck.
Though the push-pull technique was invented as a strategy to control stem-boring moths, such as Chilo partellus, through the manipulation of volatile host-finding cues, it was later discovered that allelopathic substances exuded by the roots of Desmodium spp.
[50] 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.
[53] The compound pestalone was derived from a marine fungus located in the Bahamas Islands on the surface of a brown alga, Rosenvingea sp.
[54] Some aquatic fungi have shown changes to sphingolipid production under stressors such as acid resulting in the inhibition of biofilm formation.
[57] Some vaccine adjuvants focus on biofilm formation by aiming to disrupt the communication utilizing current knowledge on quorum sensing.
[62] 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.
During this period, Thomas Eisner and his close collaborator Jerrold Meinwald published a series seminal papers on chemical defenses in plants and insects.
[64][65] 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 and Richard B. Root.
