Chemical mimicry

Chemical mimicry (also referred to as 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. 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. 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. 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, which cannot be seen, make up some of the most widely used forms of chemical mimicry and is therefore less apparent than more visual forms. As a result of this, this topic has been relatively neglected in research and literature. Two examples of organisms displaying chemical mimicry include the mimicking of Noctuid pheromones by Bolas spiders in order to draw prey to the spider’s location and the duping of insects within their own nests by mimicking their odours in order to enter and hide within the nest undetected. It is important to note that in all forms of mimicry the mimicking organism is not conscious of the deceit used and does not act intentionally to trick other organisms. Chemical mimicry (also referred to as 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. 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. 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. 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, which cannot be seen, make up some of the most widely used forms of chemical mimicry and is therefore less apparent than more visual forms. As a result of this, this topic has been relatively neglected in research and literature. Two examples of organisms displaying chemical mimicry include the mimicking of Noctuid pheromones by Bolas spiders in order to draw prey to the spider’s location and the duping of insects within their own nests by mimicking their odours in order to enter and hide within the nest undetected. It is important to note that in all forms of mimicry the mimicking organism is not conscious of the deceit used and does not act intentionally to trick other organisms. 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. 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. 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. One group of organisms that use this method are Bolas spiders (genus: Mastophora). Bolas spiders will emit chemicals that attract their prey, Noctuid moths. 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. 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. 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 genera Melittidae and Andrenidae. 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. Protective forms of chemical mimicry work to benefit the mimicking species by preventing harm. 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 form of mimicry is known as Batesian Mimicry. 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. 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. 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.