# Wyatt, ‘Pheromones’, 2017 > [!cite] > Wyatt, Tristram D. ‘Pheromones’. *Current Biology*, vol. 27, no. 15 (2017), R739–R743. https://doi.org/10.1016/j.cub.2017.06.039. > [!abstract] > The reality of invisible chemical signals, pheromones, between members of the same species was recognized long before they could be identified. Charles Darwin proposed that the breeding season sexual smells of male crocodiles, goats and other animals, too, could have evolved by sexual selection of the smelliest males through female choice. But it’s not just sex. We now know that pheromones are used by species all across the animal kingdom, in every habitat, and in a wide range of biological contexts, from trail, alarm, and queen pheromones in social insects to the mammary pheromone produced by mother rabbits. Pheromones have provided fascinating examples of signal evolution. In some model organisms, such as moths, *Drosophila*, *Caenorhabditis elegans*, and *Mus musculus*, a complete signaling system can be genetically dissected, from the enzymes producing pheromones, perception by chemosensory receptors, through to the neural circuits processing the signals. --- ‘The challenge for scientists historically was that individual animals typically release vanishingly small micro- or pico-gram quantities of pheromones. The first identification of a pheromone was not published until 1959: it had taken Adolf Butenandt and his team 20 years and required material from half a million female silk moths. Today, a single female moth’s secretion might be sufficient, analyzed by gas-chromatography–massspectrometry (GC-MS) combined with electrophysiological recordings from a male moth’s antenna to detect the active components of the pheromone blend. Many pheromones, perhaps most, consist of a particular combination of molecules, not a single molecule.’ [[Wyatt, ‘Pheromones’, 2017|(Wyatt 2017, R739)]] ^607c9d ‘Pheromones elicit stereotyped behavioural and/or physiological responses but these are modulated by context, time of day, and many other factors including the receiver’s genetics, age, sex, hormonal state, dominance status, and recent experience.’ [[Wyatt, ‘Pheromones’, 2017|(Wyatt 2017, R740)]] ^330432 ‘Pheromones are the same in all sexually mature males, for example, of a species. It is the consistency in these molecules between individual males in a population which allows them to be identified as a pheromone. Some males may produce more of the pheromone and thus may be more attractive to females: well-fed male voles with high testosterone levels produce more pheromone.’ [[Wyatt, ‘Pheromones’, 2017|(Wyatt 2017, R740)]] ^0ff2cd ‘Many bioassays measure a behavioural response as in the … suckling of a rabbit pup in response to the rabbit mammary pheromone, 2-methylbut-2-enal’. [[Wyatt, ‘Pheromones’, 2017|(Wyatt 2017, R740)]] ^42e1ce ‘… male Agrotis moths do not respond to female sex pheromone for up to 24 hours after mating’. [[Wyatt, ‘Pheromones’, 2017|(Wyatt 2017, R740)]] ^838284 ‘Even though pheromone still stimulates the olfactory sensory neurons in the male moth’s antennae, the brain response is blocked until enough time has elapsed for the male to have replenished his accessory protein stores to go with his sperm.’ [[Wyatt, ‘Pheromones’, 2017|(Wyatt 2017, R740)]] ^872055 Honey bee alarm pheromones ‘have both immediate “releaser” effects and longer lasting primer effects’. [[Wyatt, ‘Pheromones’, 2017|(Wyatt 2017, R740)]] ^ae8166 ‘In the honey bee this is reflected in changes in gene activity in the bee’s antennal lobe. For many hours after exposure to alarm pheromone, honeybees are more likely to attack intruders.’ [[Wyatt, ‘Pheromones’, 2017|(Wyatt 2017, R740)]] ^7769b6 Prairie voles (*Microtus ochrogaster*) are monogamous; they use signature mixes to recognise their ‘partner by smell.’ [[Wyatt, ‘Pheromones’, 2017|(Wyatt 2017, R740)]] ^217a85 ‘Male hamsters only respond to female pheromone if they are well fed, giving them sufficiently high blood testosterone levels in their hypothalamus.’ [[Wyatt, ‘Pheromones’, 2017|(Wyatt 2017, R740)]] ^9fdf08 ‘It is worth separating the concepts of pheromones and signature mixtures … Examples abound, from a mother sheep distinguishing her lambs from others …’ [[Wyatt, ‘Pheromones’, 2017|(Wyatt 2017. R740)]] ^137c07 ’In social insects such as ants, bees, wasps, and termites, the differences in chemical profile between colonies allow animals to distinguish nest-mates and non-nestmate conspecifics.’ [[Wyatt, ‘Pheromones’, 2017|(Wyatt 2017. R740)]] ^1efc52 ‘Social insect workers do not reproduce in the presence of queen pheromones.’ [[Wyatt, ‘Pheromones’, 2017|(Wyatt 2017. R740)]] ^816401 ‘The queen pheromone molecule(s) appeared in the gas chromatogram traces as constant peaks in all queens, overlaid on a complex colony odour background of cuticular hydrocarbons, highly variable between colonies.’ [[Wyatt, ‘Pheromones’, 2017|(Wyatt 2017. R740)]] ^f5035b ’Rodents have a wide variety of skin glands as well as large and small pheromone molecules delivered in their urine.’ [[Wyatt, ‘Pheromones’, 2017|(Wyatt 2017, R741)]] ^a521b1 ‘Darcin is secreted in the urine that dominant male mice use to mark territory signposts. Females, attracted by volatile urine pheromones, sniff the urine into their second nose, the vomeronasal organ (VNO), where darcin, an involatile pheromone, is detected. Darcin prompts the female to remember the location of the signpost and also the individual odour of the male. She will seek out the male territory owner and mate with him, recognizing him by his individual odour.’ [[Wyatt, ‘Pheromones’, 2017|(Wyatt 2017, R741)]] ^2fcbd7 ‘Pheromones are typically secreted by specialized glands or tissues. For example, female moths have a pheromone gland at the end of their abdomen. Rodents have a wide variety of skin glands as well as large and small pheromone molecules delivered in their urine. In some species, pheromones are derived or modified from other sources: tiger moth caterpillars sequester poisons from their milkweed food plants and as adults, males metabolise some of these pyrrolizidine alkaloid poisons into volatile pheromones, attractive to females and indicative of the size of poison gift they will transfer along with sperm at mating.’ [[Wyatt, ‘Pheromones’, 2017|(Wyatt 2017, R741)]] ^122ddd ‘However, there might be a human mammary pheromone, suggested by the response of human babies to secretions from any lactating mother, not just their own. Babies suck in response to secretions from the areola gland around the nipple.’ [[Wyatt, ‘Pheromones’, 2017|(Wyatt 2017, R743)]] ^1505cf ![[Wyatt 2017, 'Pheromones’, Current Biology, p. R739. Box 1, an operational definition of pheromones..png]] [[Wyatt, ‘Pheromones’, 2017|(Wyatt 2017, R739)]] ^ce493a ‘During speciation, changes in sex pheromones commonly form one basis of pre-mating isolation. This may explain the chemosignal differences in major urinary proteins and androgen binding proteins in *Mus musculus* subspecies in hybrid zones.’ [[Wyatt, ‘Pheromones’, 2017|(Wyatt 2017, R742)]] ^1a7bcf ‘By contrast, hyena anal gland secretions contain relatively involatile high molecular weight molecules for long lasting marks for territory marking.’ [[Wyatt, ‘Pheromones’, 2017|(Wyatt 2017, R742)]] ^032160 ‘We now know that pheromones are used by species all across the animal kingdom, in every habitat, and in a wide range of biological contexts, from trail, alarm, and queen pheromones in social insects to the mammary pheromone produced by mother rabbits.’ [[Wyatt, ‘Pheromones’, 2017|(Wyatt 2017, R39)]] ^7e72cb