Aggressive mimicry
Aggressive mimicry is a form of
Aggressive mimicry is opposite in principle to defensive mimicry, where the mimic generally benefits from being treated as harmful. The mimic may resemble its own prey, or some other organism which is beneficial or at least not harmful to the prey. The model, i.e. the organism being 'imitated', may experience increased or reduced fitness, or may not be affected at all by the relationship. On the other hand, the signal receiver inevitably suffers from being tricked, as is the case in most mimicry complexes.
Aggressive mimicry often involves the predator employing signals which draw its potential prey towards it, a strategy which allows predators to simply sit and wait for prey to come to them. The promise of food or sex are most commonly used as lures. However, this need not be the case; as long as the predator's true identity is concealed, it may be able to approach prey more easily than would otherwise be the case. In terms of species involved, systems may be composed of two or three species; in two-species systems the signal receiver, or "dupe", is the model.
In terms of the visual dimension, the distinction between aggressive mimicry and camouflage is not always clear. Authors such as Wickler[8] have emphasized the significance of the signal to its receiver as delineating mimicry from camouflage. However, it is not easy to assess how 'significant' a signal may be for the dupe, and the distinction between the two can thus be rather fuzzy. Mixed signals may be employed: aggressive mimics often have a specific part of the body sending a deceptive signal, with the rest being hidden or camouflaged.
Contrast with defensive mimicry
Aggressive mimicry stands in semantic contrast with defensive mimicry, where it is the prey that acts as a mimic, with
Classification
Luring prey
In some cases the signal receiver is lured toward the mimic. This involves mimicry of a resource that is often vital to the prey's survival (or more precisely, the survival of its genes) such as nutrition or a mate. If the bait offered is of little value to prey they would not be expected to take such a risk. For example, in all known cases of sexual signal mimicry it is always the male sex that is deceived (in fact, it has been suggested that females of some species have evolved mimicry as a strategy to avoid unwanted matings).[10] In these cases the predator need not move about foraging for prey, but may simply stay still and allow prey to come to it. Some studies suggest that the northern shrike (Lanius excubitor) sings in winter often imitating small passerines that may be preyed upon when lured within reach.[11] There has been one report of a
Appearance of food
Many aggressive mimics use the promise of nourishment as a way of attracting prey. The alligator snapping turtle (Macrochelys temminckii) is a well-camouflaged ambush predator. Its tongue bears a conspicuous pink extension that resembles a worm and can be wriggled around;[13] fish that try to eat the "worm" are themselves eaten by the turtle. Similarly, some snakes employ caudal luring (using the tail)[14][15] or lingual luring (using the tongue) to entice small vertebrates into striking range.[16][17]
Aggressive mimicry is common amongst
Spiders can be the prey of aggressive mimics. The
Larvae of the
Although plants are better known for defensive mimicry, there are exceptions. For example, many flowers use mimicry to attract pollinators, while others may trick insects into dispersing their seeds. Nonetheless, most mimicry in plants[b] would not be classified as aggressive, as although luring pollinators is similar to cases above, they are certainly not eaten by the plant. However some carnivorous plants may be able to increase their rate of capture through mimicry.[24] For example, some have patterns in the ultraviolet region of the electromagnetic spectrum, much like the spider webs described above.[25]
Bipolar mimicry systems
Mimicry systems involving only two species are known as bipolar.
Batesian-Wallacian or prey mimicry
In some cases of Batesian-Wallacian mimicry, the model is a sexually receptive female, which provides a strong attractive effect on males. Some spiders use chemical rather than visual means to ensnare prey. Female
The listroscelidine katydid
Female
Kirbyan or brood parasite mimicry
Host-parasite mimicry is a situation where a parasite mimics its own host. As with mimicry of the female sex outlined previously, only two species are involved, the model and mimic being of the same species. Brood parasitism, a form of kleptoparasitism where the mother has its offspring raised by another unwitting organism, is one such situation where host-parasite mimicry has evolved. Georges Pasteur[9] terms this form of aggressive-reproductive mimicry Kirbyan mimicry, after the English entomologist William Kirby.[33]
Wicklerian-Eisnerian or mimicry of harmless species
The prey does not have to be attracted towards the predator for the predator to benefit: it is sufficient for the predator simply not to be identified as a threat. Wicklerian-Eisnerian mimics may resemble a mutualistic ally, or a species of little significance to the prey such as a commensal.[9] For example, the hemipteran Arachnocoris berytoides resembles Faiditus caudatus, a spider commensal of ants.[34]
Mimicry of cleaner fish
Mimicry of mutualistic species is seen in coral reef fish, where the models, certain
Mimesis
Parasites mimicking host prey
Just as predators such as
One such case is a genus of mussel, Lampsilis, which feeds on the gills of fish in the larval stage of their development. Once they mature, they leave the fish as adult mollusc. Gaining entry into the host is not an easy task though, despite the fact that several hundred thousand larvae are released at once. This is especially the case in flowing water bodies such as streams, where they cannot lie on the substrate and wait to be taken up in the course of foraging. Female Lampsilis have evolved a special technique for delivering their offspring into a suitable host, however. Structures on the edge of the mantle are able to capture the interest of fish. Some resemble small fish themselves, with eye spots, a "tail" and horizontal stripes, and may even move in a similar fashion, as if facing the current (rheotaxis). When overshadowed by a fish, the larvae are forcefully expelled, becoming ecto-parasites on their unsuspecting host.[8] Some species of Lampsilis, notably Lampsilis ovata, attract fish in the genus Micropterus, Villosa has fish-like mantle lures that attract predatory fish Percina.[40]
Cercaria mirabilis, a
Another parasitic trematode example is seen in a terrestrial setting.
Wolf in sheep's clothing
Zoologists have repeatedly compared aggressive mimicry to the
See also
- Anti-predator adaptation – Defensive feature of prey for selective advantage
- Apparent death – Behavior in which animals take on the appearance of being dead
- Wolf in sheep's clothing – Idiom of Biblical origin to describe those playing a role contrary to their real character
Notes
- ^ Pasteur (1982) describes the term as redundant and states that there are many different forms of aggressive mimicry. The term was used earlier by Bates (1862) and Kirby & Spence (1823).
- ^ For an overview of mimicry in plants, see Wiens, 1978. Some plants mimic inanimate objects such as stones, as in Mesembryanthemum, clearly not aggressive. Some entomophilous plants such as the bee orchid attract pollinators by mimicking female insects, the males attempting to mate with the flower, but the duped insects are not eaten, and the mimicry is thus not aggressive. In Vavilovian mimicry, weeds of crops have evolved seeds similar to those of the crop, enabling the weed to be propagated by being planted as crop seed. But again, this cannot be called aggressive.[22][23]
- cannibalisticspecies where a cannibalistic organism individual mimics another species.
References
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- ^ PMID 19570776.
Cosmophasis bitaeniata, like comparable examples from insects (Eisner et al. 1978; Lucas & Brodeur 2001), can be likened to a wolf in sheep's clothing (e.g. Eisner et al. 1978). These predators practise aggressive mimicry by making it easy for prey to misidentify the predator as just another member of a prey group, as though lulling the prey into a false sense of security.
- ^ PMID 29364905.
- ^ ISBN 978-1-4833-8898-4.
In aggressive mimicry, the predator is 'a wolf in sheep's clothing'. Mimicry is used to appear harmless or even attractive to lure its prey.
- S2CID 37649827.
- ^ Peckham, Elizabeth G. (1889). "Protective resemblances of spiders" (PDF). Occasional Papers of Natural History Society of Wisconsin. 1: 61–113.
- ^ Peckham, Elizabeth G.; Peckham, George W. (1892). "Ant-like spiders of the family Attidae" (PDF). Occasional Papers of Natural History Society of Wisconsin. 2: 1–84.
- ^ a b c d Wickler, Wolfgang (1968). Mimicry in plants and animals. McGraw-Hill.
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- ^ Craig, C. L. (1995). "Webs of Deceit". Natural History. 104 (3): 32–35.
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- ^ Wallace, Alfred R. (1870). "Mimicry, and other protective resemblances among animals". Contributions to the Theory of Natural Selection. A Series of Essays. Macmillan. pp. 45–129.
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- ^ Kirby, W., Spence, W. 1823. An Introduction to Entomology, vol. 2. London: Longman, Hurst, Rees, Orme & Brown. 3rd ed.
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- ^ Clark, William S. (2004). "Is the Zone-tailed Hawk a Mimic?". Birding. 36 (5): 495–498.
- ^ a b Wickler, Wolfgang (1998). "Mimicry". Encyclopædia Britannica, 15th edition. Macropædia 24, 144–151. http://www.britannica.com/eb/article-11910
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- ^ See here for a photo.
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The dual strategy developed by the aphid P. cimiciformis outlines a complex evolutionary scenario. On the one hand, the round morph and the ants, engaged in a trophobiotic relationship, should be subjected to the conflicts of interest typical of mutualism, with selection driving each partner to maximize its benefit by giving the least of its own energy and resources. On the other hand, the flat morph and the ants can be expected to be engaged in an arms race, with selection favoring improved deceiving abilities in the aphid and increasingly finer discrimination abilities to detect noncolony members in the ants. ... We believe that, beyond providing an unusual case of a 'wolf in sheep's clothing,' this system opens up a host of interesting and potentially novel questions about the evolution of cooperation and exploitation.
- ISBN 978-94-009-3105-3.
- ^ "Wolf in Sheep's Clothing: How Scale-Eating Cichlid Fish Trick Their Prey". University of Basel. 23 September 2015. Retrieved 2 February 2018.
The results reveal the complexity of this so-called 'aggressive mimicry': the scale-eaters are actually imitating several blue and white striped species at once, in order to trick an entire natural community. The leader of the study, Prof. Walter Salzburger, summarizes the findings thus: 'The scale-eater pursues the strategy of a wolf that dresses up as a sheep only to then go for goats and cows.'
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- ^ ISBN 978-0-674-04379-4.
Others rely on the technique adopted by a wolf in sheep's clothing—they mimic a harmless species. ... Other predators even mimic their prey's prey: angler fish (Lophiiformes) and alligator snapping turtles Macroclemys temmincki can wriggle fleshy outgrowths of their fins or tongues and attract small predatory fish close to their mouths.
- ^ Stolesen, Scott H.; Sadoti, Giancarlo (2010). "Chapter 17: Zone-tailed Hawk (Buteo albonotatus)". In Cartron, Jean-Luc E. (ed.). Raptors of New Mexico (PDF). University of New Mexico Press. pp. 297–313.
Willis (1963) postulated that the Zone-tail's strong physical resemblance to the Turkey Vulture may be a form of aggressive mimicry, which allows the hawk to closely approach potential prey that are habituated to the presence of the ubiquitous vultures (but see Mueller 1972). Snyder and Snyder (1991) report the capture success rate of Zone-tails in Arizona was significantly greater when soaring with vultures (30% successful) than when flying alone (7% successful), based on a sample of 55 observations. It is noteworthy that once a Zone-tail flying among vultures has spotted potential prey (as indicated by its locking its gaze on one spot on the ground), it often continues soaring past until well beyond the intended victim, often beyond some cover, at which point it stoops back at an acute angle in a surprise attack (Snyder and Glinski 1988; SHS).
Further reading
- ISBN 0-07-070100-8.
- Pietsch, T. W.; Grobecker, D. B. (1978). "The Compleat Angler: Aggressive Mimicry in an Antennariid Anglerfish". S2CID 45349001.
- Lloyd, J. E. (1981). "Mimicry in the sexual signals of fireflies". .
- Nicolai, J. (October 1974). "Mimicry in parasitic birds". Scientific American. 231: 93–98.
External links
- Feeding behavior of the frogfishes (Antennariidae) Description, images and video of aggressive mimicry in frogfish
- Acoustic aggressive mimicry of cicadas by an Australian predatory katydid