Emsleyan mimicry
Emsleyan mimicry, also called Mertensian mimicry, describes an unusual type of mimicry where a deadly prey mimics a less dangerous species.[1]
History
Emsleyan mimicry was first proposed by M. G. Emsley
Mimicry of a less deadly species
The scenario for Emsleyan mimicry is a little more difficult to understand than for other types of mimicry, since in other types of mimicry it is usually the most harmful species that is the model. But if a predator dies, it cannot learn to recognize a warning signal, e.g., bright colours in a certain pattern. In other words, there is no advantage in being aposematic for an organism that is likely to kill any predator it succeeds in poisoning; such an animal is better off being camouflaged, to avoid attacks altogether. If, however, there were some other species that were harmful but not deadly as well as aposematic, the predator could learn to recognize its particular warning colours and avoid such animals. A deadly species could then profit by mimicking the less dangerous aposematic organism if this reduces the number of attacks.[5][6]
Non-Emsleyan mechanisms
Non-Emsleyan mechanisms that achieve the observed result, namely that predators avoid extremely deadly prey, are possible. Proposed alternatives include observational learning and innate avoidance.[8][7] These provide alternative explanations to Emsleyan mimicry: if predators innately avoid a pattern then there is no need to suppose that the more deadly snake is mimicking the less deadly species in these cases.[9]
Observational learning
One mechanism is observational learning, for example through watching a conspecific die. The observing predator then remembers that the prey is deadly and avoids it. Jouventin and colleagues conducted exploratory tests on baboons in 1977 that suggested this was possible.[8]
Innate avoidance
Another possible mechanism is that a predator might not have to learn that a certain prey is harmful in the first place: it could have instinctive genetic programming to avoid certain signals. In this case, other organisms could benefit from this programming, and Batesian or Müllerian mimics of it could potentially evolve.[7] Some species indeed do innately recognize certain aposematic patterns. Hand-reared
The models would not have to be other snakes. Large red and black millipedes are common and foul-tasting; various species of these millipedes form Müllerian mimicry rings, and some are the models for mimicry in lizards.[10]
Coral snake system
Some harmless
It has been suggested that this system could be an instance of pseudomimicry, the similar colour patterns having evolved independently in similar habitats.[11]
References
- .
- ^ PMID 28562911.
- ^ Wickler, Wolfgang (1968). Mimicry in plants and animals. McGraw-Hill.
- ^ Mertens, Robert (1956). "Das Problem der Mimikry bei Korallenschlangen". Zool. Jahrb. Syst (in German). 84: 541–76.
- ^ S2CID 83825414.
- ^ JSTOR 2762.
- ^ S2CID 41092574.
- ^ PMID 28567722.
- ^ S2CID 40138205.
- ^ ISBN 978-1118931516.
- JSTOR 1563495.