A pheromone is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavior of the receiving individuals. There are alarm pheromones, food trail pheromones, sex pheromones, and many others that affect behavior or physiology. Pheromones are used by many organisms, from basic unicellular prokaryotes to complex multicellular eukaryotes. Their use among insects has been particularly well documented. In addition, some vertebrates, plants and ciliates communicate by using pheromones. The ecological functions and evolution of pheromones are a major topic of research in the field of chemical ecology.
In evolutionary biology, mimicry is an evolved resemblance between an organism and another object, often an organism of another species. Mimicry may evolve between different species, or between individuals of the same species. In the simplest case, as in Batesian mimicry, a mimic resembles a model, so as to deceive a dupe, all three being of different species. A Batesian mimic, such as a hoverfly, is harmless, while its model, such as a wasp, is harmful, and is avoided by the dupe, such as an insect-eating bird. Birds hunt by sight, so the mimicry in that case is visual, but in other cases mimicry may make use of any of the senses. Most types of mimicry, including Batesian, are deceptive, as the mimics are not harmful, but Müllerian mimicry, where different harmful species resemble each other, is honest, as when species of wasps and of bees all have genuinely aposematic warning coloration. More complex types may be bipolar, involving only two species, such as when the model and the dupe are the same; this occurs for example in aggressive mimicry, where a predator in wolf-in-sheep's-clothing style resembles its prey, allowing it to hunt undetected. Mimicry is not limited to animals; in Pouyannian mimicry, an orchid flower is the mimic, resembling a female bee, its model; the dupe is the male bee of the same species, which tries to copulate with the flower, enabling it to transfer pollen, so the mimicry is again bipolar. In automimicry, another bipolar system, model and mimic are the same, as when blue lycaenid butterflies have 'tails' or eyespots on their wings that mimic their own heads, misdirecting predator dupes to strike harmlessly. Many other types of mimicry exist.
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. Chemical ecologists seek to identify the specific molecules that function as signals mediating 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 molecules, but can also include larger molecules and small peptides.
Batesian mimicry is a form of mimicry where a harmless species has evolved to imitate the warning signals of a harmful species directed at a predator of them both. It is named after the English naturalist Henry Walter Bates, who worked on butterflies in the rainforests of Brazil.
Müllerian mimicry is a natural phenomenon in which two or more well-defended species, often foul-tasting and sharing common predators, have come to mimic each other's honest warning signals, to their mutual benefit. The benefit to Müllerian mimics is that predators only need one unpleasant encounter with one member of a set of Müllerian mimics, and thereafter avoid all similar coloration, whether or not it belongs to the same species as the initial encounter. It is named after the German naturalist Fritz Müller, who first proposed the concept in 1878, supporting his theory with the first mathematical model of frequency-dependent selection, one of the first such models anywhere in biology.
An allomone is a type of semiochemical produced and released by an individual of one species that affects the behaviour of a member of another species to the benefit of the originator but not the receiver. Production of allomones is a common form of defense against predators, particularly by plant species against insect herbivores. In addition to defense, allomones are also used by organisms to obtain their prey or to hinder any surrounding competitors.
A semiochemical, from the Greek σημεῖον (semeion), meaning "signal", is a chemical substance or mixture released by an organism that affects the behaviors of other individuals. Semiochemical communication can be divided into two broad classes: communication between individuals of the same species (intraspecific) or communication between different species (interspecific).
A kairomone is a semiochemical, emitted by an organism, which mediates interspecific interactions in a way that benefits an individual of another species which receives it and harms the emitter. This "eavesdropping" is often disadvantageous to the producer. The kairomone improves the fitness of the recipient and in this respect differs from an allomone and a synomone. The term is mostly used in the field of entomology. Two main ecological cues are provided by kairomones; they generally either indicate a food source for the receiver, or the presence of a predator, the latter of which is less common or at least less studied.
Interspecies communication is communication between different species of animals, plants, or microorganisms.
Ant mimicry or myrmecomorphy is mimicry of ants by other organisms; it has evolved over 70 times. Ants are abundant all over the world, and potential predators that rely on vision to identify their prey, such as birds and wasps, normally avoid them, because they are either unpalatable or aggressive. Some arthropods mimic ants to escape predation, while some predators of ants, especially spiders, mimic them anatomically and behaviourally in aggressive mimicry. Ant mimicry has existed almost as long as ants themselves; the earliest ant mimics in the fossil record appear in the mid-Cretaceous alongside the earliest ants.
Eusociality is the highest level of organization of sociality. It is defined by the following characteristics: cooperative brood care, overlapping generations within a colony of adults, and a division of labor into reproductive and non-reproductive groups. The division of labor creates specialized behavioral groups within an animal society which are sometimes referred to as 'castes'. Eusociality is distinguished from all other social systems because individuals of at least one caste usually lose the ability to perform behaviors characteristic of individuals in another caste. Eusocial colonies can be viewed as superorganisms.
Insects are hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body, three pairs of jointed legs, compound eyes, and a pair of antennae. Insects are the most diverse group of animals, with more than a million described species; they represent more than half of all animal species.
Chemical mimicry is a type of biological mimicry involving the use of chemicals to dupe an operator.
Green leaf volatiles (GLV) are organic compounds released by plants. Some of these chemicals function as signaling compounds between either plants of the same species, of other species, or even different lifeforms like insects.
Insects have a wide variety of predators, including birds, reptiles, amphibians, mammals, carnivorous plants, and other arthropods. The great majority (80–99.99%) of individuals born do not survive to reproductive age, with perhaps 50% of this mortality rate attributed to predation. In order to deal with this ongoing escapist battle, insects have evolved a wide range of defense mechanisms. The only restraint on these adaptations is that their cost, in terms of time and energy, does not exceed the benefit that they provide to the organism. The further that a feature tips the balance towards beneficial, the more likely that selection will act upon the trait, passing it down to further generations. The opposite also holds true; defenses that are too costly will have a little chance of being passed down. Examples of defenses that have withstood the test of time include hiding, escape by flight or running, and firmly holding ground to fight as well as producing chemicals and social structures that help prevent predation.
Trail pheromones are semiochemicals secreted from the body of an individual to affect the behavior of another individual receiving it. Trail pheromones often serve as a multi purpose chemical secretion that leads members of its own species towards a food source, while representing a territorial mark in the form of an allomone to organisms outside of their species. Specifically, trail pheromones are often incorporated with secretions of more than one exocrine gland to produce a higher degree of specificity. Considered one of the primary chemical signaling methods in which many social insects depend on, trail pheromone deposition can be considered one of the main facets to explain the success of social insect communication today. Many species of ants, including those in the genus Crematogaster use trail pheromones.
In evolutionary biology, mimicry in plants is where a plant evolves to resemble another organism physically or chemically. Mimicry in plants has been studied far less than mimicry in animals, with fewer documented cases and peer-reviewed studies. However, it may provide protection against herbivory, or may deceptively encourage mutualists, like pollinators, to provide a service without offering a reward in return.
A phytobiome consists of a plant (phyto) situated in its specific ecological area (biome), including its environment and the associated communities of organisms which inhabit it. These organisms include all macro- and micro-organisms living in, on, or around the plant including bacteria, archaea, fungi, protists, insects, animals, and other plants. The environment includes the soil, air, and climate. Examples of ecological areas are fields, rangelands, forests. Knowledge of the interactions within a phytobiome can be used to create tools for agriculture, crop management, increased health, preservation, productivity, and sustainability of cropping and forest systems.
Symphiles are insects or other organisms which live as welcome guests in the nest of a social insect by which they are fed and guarded. The relationship between the symphile and host may be symbiotic, inquiline or parasitic.
Insect pheromones are neurotransmitters that serve the chemical communication between individuals of an insect species. They thus differ from kairomones, in other words, neurotransmitters that transmit information to non-species organisms. Insects produce pheromones in special glands and release them into the environment. In the pheromone receptors of the sensory cells of the recipient, they produce a nerve stimulus even in very low concentrations, which ultimately leads to a behavioral response. Intraspecific communication of insects via these substances takes place in a variety of ways and serves, among other things, to find sexual partner, to maintain harmony in a colony of socially living insects, to mark territories or to find nest sites and food sources.
