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THE FLY IN THE OINTMENT. “Male tilapia sex pheromones have multiple effects.” https://lnkd.in/drx5_4e View in LinkedIn

PHYSIOLOGICAL PRIMERS. “Many bioassays measure a behavioural response as in the silk moth or the suckling of a rabbit pup in response to the rabbit mammary pheromone, 2-methylbut-2-enal. Other pheromones need different kinds of bioassays as they have physiological (‘primer’) effects. Many pheromones, such as male tilapia urinary pheromones and honeybee alarm pheromone, have both immediate ‘releaser’ effects and longer lasting primer effects. 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.” https://lnkd.in/drx5_4e View in LinkedIn

BIOASSAY REQUIRED. “Butenandt used the wing fluttering response of the male silk moth as the bioassay to track the female sex pheromone activity in his solvent fractionations and to later confirm that the synthesized molecule, bombykol, was indeed the pheromone. Such bioassays, repeatable experiments designed to measure a biological response, are still an essential part of pheromone identification. Without this systematic approach, no claim that a molecule or combination of molecules is a pheromone is credible.” https://lnkd.in/drx5_4e View in LinkedIn

DOPING MIXTURE. “Many pheromones, perhaps most, consist of a particular combination of molecules, not a single molecule.” https://lnkd.in/drx5_4e View in LinkedIn

METHODS IMPROVED. “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–mass-spectrometry (GC-MS) combined with electrophysiological recordings from a male moth’s antenna to detect the active components of the pheromone blend.” https://lnkd.in/drx5_4e View in LinkedIn

CHEMICAL SIGNAL CHAIN. “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.” https://lnkd.in/drx5_4e View in LinkedIn

QUESTION. Isn’t it just a tiny bit curious that we are, ostensibly, so ignorant about human pheromones when they are used universally in nature? View in LinkedIn

ACROSS ALL TAXA. “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.” https://lnkd.in/drx5_4e View in LinkedIn

SO ENDS this first of two weekends on the subject of pheromones. Universal, complex, and very diverse, these molecules operate in addition to other modes of communication, layered on top as a primary, perhaps more primitive, sense. It is stunning that sexual attraction is so determined by these molecules, which, in turn, reflect the biological fitness of the partner. And probably not far disconnected from the molecules of quorum sensing used by bacteria. View in LinkedIn

MATING CUE. “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.” Ever smelled a billy goat? View in LinkedIn