Chemical mimicry (or molecular mimicry) is a type of biological mimicry involving the use of chemicals to dupe an operator.
A chemical mimic dupes an operator (e.g. a predator) by showing an adaptive chemical resemblance to an object of its environment and as a consequence receives selective advantage. [1] In all cases of chemical mimicry it has been found that the mimicking species is the only species to benefit from the reaction with either costs or no effect on the duped species. [2]
This is by adapting to produce chemicals (ex: allomones, pheromones, odours, etc.) that will cause a desirable behavioural reaction in the species being deceived and a selective advantage to the mimic, as in ant mimicry. [3] Chemical mimicry exists within many of the different forms of mimicry such as aggressive, protective, Batesian, and Müllerian mimicry and can involve a number of different senses.
Mimicking semiochemicals make up some of the most widely used forms of chemical mimicry, but is less apparent than more visual forms. [2] As a result, this topic has been relatively neglected in research and literature. [2]
Two examples of organisms displaying chemical mimicry are the mimicking of Noctuid pheromones by bolas spiders to lure prey and the duping of insects within their own nests by mimicking their odours in order to enter and hide within the nest undetected. [4]
Chemical mimicry exists in many forms and for a variety of uses. It may be classified by the function it performs for the mimicking species and the effect that the mimic will have on the species that is deceived. It can be used for such functions as deterring predators, drawing prey, to allow a parasite to deceive a host species, or to help assist in the reproduction of an organism.
Aggressive mimicry through the use of chemicals is used among a wide variety of animals. It functions to either lure the deceived organism to the deceiver or it allows for the organism to accept the presence of a parasite. The chemical mimicry used by parasites allows for the deceived organism to accept the presence of the deceiver while they benefit from either taking up food supplies or directly preying on the host species from within their nest. [2]
Chemical mimicry of an organism's pheromones allows predators with this ability to draw select prey to them, rather than spend their energy finding and attempting to capture these organisms with varied success. [2] The pheromones are typically used by the prey species to attract members of their own species as potential mates. In the case of predatory chemical mimicry, the predator has evolved to emit chemicals that are structurally similar and will cause the same behavioural reactions to be displayed by the prey. However, the mimicked pheromones will draw the animal toward the predator rather than a potential mate. [2]
One group of organisms that use this method are Bolas spiders (genus: Mastophora ). Bolas spiders emit chemicals that attract their prey, noctuid moths. [5] These spiders have replaced the need to spin elaborate webs to capture prey by mimicking the pheromones emitted by female moths to attract males of the species effectively. In studies conducted on this spider it has been found that the moths only approach from downwind of the spider and that all of the moths captured were, in fact, male. [5]
Parasitic use of chemical mimicry involves the invasion of the nest of a duped species, which may consist of an individual or a colony. By emitting mimics of the chemicals that create the host's familiar odours the invader is able to conceal themselves efficiently within the nest without alerting the host. [4]
One example of a group of insects that uses this method of chemical mimicry would be cuckoo bees (genus: Nomada ). Cuckoo bees will parasitize bees of the families Melittidae and Andrenidae. [4] Cuckoo bee males will produce chemicals that are similar in structure to the volatile lipids secreted by host females and these chemicals are transferred to cuckoo females so that they may camouflage their eggs within the host's nest. This would allow the females to pass off the care of her eggs and larvae onto the host, benefiting the parasite and burdening the host. [4]
Protective forms of chemical mimicry work to benefit the mimicking species by preventing harm. [2] In most cases this achieved by acting as a deterrent to other organisms by mimicking the chemicals emitted by another species that has a mechanism to deter predators. This can be either Batesian Mimicry or Müllerian mimicry. [6]
In Batesian mimicry, potential prey organisms will mimic chemicals emitted by an organism that poses a greater risk to the predator in order to deter attack. [6] Most commonly this form of chemical mimicry is seen in plant species through the release of mimicked defense chemicals. The organism being mimicked may contain noxious chemicals used to deter predators from consuming them as it will lead to the predator becoming ill. [7] By using Batesian mimicry the operator will mimic a chemical aspect, such as “defense signals" used by plants, in order to deceive the herbivore or predator into avoiding an edible organism. [7]
Chemical mimicry can also have benefits on the reproductive success of the operator. This form is used primarily by flowers in order to deceive pollinators. There are two main types, the first being pseudocopulation which involves attracting male pollinators by mimicking the pheromones of females of the species. [4] The second type involves female plants mimicking the chemical signals of males of the same species. By doing this the female plant is able to draw more pollinators despite not producing the pollen that the animal is looking for. [4]
Pseudocopulation is achieved when a flower successfully mimics the appearance and the pheromones emitted by the female of an insect species. [4] [8] The chemicals emitted by the mimicking species work to draw these pollinators to the plant and increase the number of visits to and time spent on the flower. This increases the chances that pollen will efficiently stick to the organism or that pollen already stuck to it is transferred to the plant. [4]
In one study on mining bees ( Andrena nigroaenea ) and spider orchids ( Ophrys sphegodes Mill.) it was found that unpollinated spider orchids emitted odours that consisted of hydrocarbons that were an exact match for the odours released by virgin female bees. [4] As a result, male mining bees are extremely attracted to the flowers of the spider orchid, triggering more quick visits to the flower and in some cases the male bees attempt copulation, either getting themselves sufficiently covered in pollen or successfully transferring it to another plant. [4]
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. Often, mimicry functions to protect a species from predators, making it an anti-predator adaptation. Mimicry evolves if a receiver perceives the similarity between a mimic and a model and as a result changes its behaviour in a way that provides a selective advantage to the mimic. The resemblances that evolve in mimicry can be visual, acoustic, chemical, tactile, or electric, or combinations of these sensory modalities. Mimicry may be to the advantage of both organisms that share a resemblance, in which case it is a form of mutualism; or mimicry can be to the detriment of one, making it parasitic or competitive. The evolutionary convergence between groups is driven by the selective action of a signal-receiver or dupe. Birds, for example, use sight to identify palatable insects and butterflies, whilst avoiding the noxious ones. Over time, palatable insects may evolve to resemble noxious ones, making them mimics and the noxious ones models. In the case of mutualism, sometimes both groups are referred to as "co-mimics". It is often thought that models must be more abundant than mimics, but this is not so. Mimicry may involve numerous species; many harmless species such as hoverflies are Batesian mimics of strongly defended species such as wasps, while many such well-defended species form Müllerian mimicry rings, all resembling each other. Mimicry between prey species and their predators often involves three or more species.
The large blue is a species of butterfly in the family Lycaenidae. The species was first defined in 1758 and first recorded in Britain in 1795. In 1979 the species became mostly extinct in Britain but has been successfully reintroduced with new conservation methods. The species is classified as "near threatened" on the IUCN Red List of Threatened Species. Today P. arion can be found in Europe, the Caucasus, Armenia, western Siberia, Altai, north-western Kazakhstan and Sichuan.
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, after his work on butterflies in the rainforests of Brazil.
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).
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.
Flower mantises are praying mantises that use a special form of camouflage referred to as aggressive mimicry, which they not only use to attract prey, but avoid predators as well. These insects have specific colorations and behaviors that mimic flowers in their surrounding habitats.
Aggressive mimicry is a form of mimicry in which predators, parasites, or parasitoids share similar signals, using a harmless model, allowing them to avoid being correctly identified by their prey or host. Zoologists have repeatedly compared this strategy to a wolf in sheep's clothing. In its broadest sense, aggressive mimicry could include various types of exploitation, as when an orchid exploits a male insect by mimicking a sexually receptive female, but will here be restricted to forms of exploitation involving feeding. For example, indigenous Australians who dress up as and imitate kangaroos when hunting would not be considered aggressive mimics, nor would a human angler, though they are undoubtedly practising self-decoration camouflage. Treated separately is molecular mimicry, which shares some similarity; for instance a virus may mimic the molecular properties of its host, allowing it access to its cells. An alternative term, Peckhamian mimicry, has been suggested, but it is seldom used.
Philanthus gibbosus, which is commonly referred to as a beewolf due to its predation practices, is a species of bee-hunting wasp and is the most common and widespread member of the genus in North America. P. gibbosus is of the order Hymenoptera and the genus Philanthus. It is native to the Midwestern United States and the western Appalachians. P. gibbosus are often observed to visit flowers and other plants in search of insect prey to feed their young. The prey that P. gibbosus catches is then coated in a layer of pollen and fed to the young wasps.
Bombus lapidarius is a species of bumblebee in the subgenus Melanobombus. Commonly known as the red-tailed bumblebee, B. lapidarius can be found throughout much of Central Europe. Known for its distinctive black and red body, this social bee is important in pollination.
Bombus vestalis, the vestal cuckoo bumblebee, is a species of cuckoo bumblebee that lives in most of Europe, as well as North Africa and western Asia. It is a brood parasite that takes over the nests of other bee species. Its primary host is Bombus terrestris. After its initial classification as Psithyrus vestalis, this bumblebee recently was reclassified into the genus Bombus, subgenus Psithyrus.
Bombus bohemicus, also known as the gypsy's cuckoo bumblebee, is a species of socially parasitic cuckoo bumblebee found in most of Europe with the exception of the southern Iberian Peninsula and Iceland. B. bohemicus practices inquilinism, or brood parasitism, of other bumblebee species. B. bohemicus is a generalist parasite, successfully invading several species from genus Bombus. The invading queen mimics the host nest's chemical signals, allowing her to assume a reproductively dominant role as well as manipulation of host worker fertility and behavior.
A wasp is any insect of the narrow-waisted suborder Apocrita of the order Hymenoptera which is neither a bee nor an ant; this excludes the broad-waisted sawflies (Symphyta), which look somewhat like wasps, but are in a separate suborder. The wasps do not constitute a clade, a complete natural group with a single ancestor, as bees and ants are deeply nested within the wasps, having evolved from wasp ancestors. Wasps that are members of the clade Aculeata can sting their prey.
Diptera is an order of winged insects commonly known as flies. Diptera, which are one of the most successful groups of organisms on Earth, are very diverse biologically. None are truly marine but they occupy virtually every terrestrial niche. Many have co-evolved in association with plants and animals. The Diptera are a very significant group in the decomposition and degeneration of plant and animal matter, are instrumental in the breakdown and release of nutrients back into the soil, and whose larvae supplement the diet of higher agrarian organisms. They are also an important component in food chains.
In evolutionary biology, mimicry in plants is where a plant organism evolves to resemble another organism physically or chemically, increasing the mimic's Darwinian fitness. 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.
Deception in animals is the transmission of misinformation by one animal to another, of the same or different species, in a way that propagates beliefs that are not true.
Locomotor mimicry is a subtype of Batesian mimicry in which animals avoid predation by mimicking the movements of another species phylogenetically separated. This can be in the form of mimicking a less desirable species or by mimicking the predator itself. Animals can show similarity in swimming, walking, or flying of their model animals.
Mallophora bomboides, also known as the Florida bee killer, is a predaceous species of robber fly of the family Asilidae that feeds primarily on bumblebees. M. bomboides is a noteworthy instance of Batesian mimicry given its close resemblance to its prey, the bumblebee. These bees are typically found in the Eastern and Southern regions of the United States like South Carolina and Florida.
Mastophora hutchinsoni, also known as the American bolas spider, is a species of orb weaver in the genus Mastophora. The genus is distributed extensively throughout various subtropical geographical areas including Australia, South Africa, Oriental Asia, and the Americas and is not found in Europe. The hunting behavior of adult female M. hutchinsoni is unusual because they are bolas spiders. They mimic moth pheromones to attract male moths, and female M. hutchinsoni have evolved to alter their chemical release to target different moths. They then capture their prey with a sticky drop on the end of a silk line, resembling a bolas.
In evolutionary biology, mimicry in vertebrates is mimicry by a vertebrate of some model, deceiving some other animal, the dupe. Mimicry differs from camouflage as it is meant to be seen, while animals use camouflage to remain hidden. Visual, olfactory, auditory, biochemical, and behavioral modalities of mimicry have been documented in vertebrates.
Chemical communication in insects is social signalling between insects of the same or different species, using chemicals. These chemicals may be volatile, to be detected at a distance by other insects' sense of smell, or non-volatile, to be detected on an insect's cuticle by other insects' sense of taste. Many of these chemicals are pheromones, acting like hormones outside the body.