Agrresive Mimicry

So far we have looked at forms of mimicry that aid in defense of the organisms. This time we shall have have a look at "Aggressive" mimicry. Agressive mimicry is employed by predators, parasites and parasitoids. It functions in such a way that these organisms give of harmless signals to their prey/host allowing them to remain undetected. They may model the design of the prey species themselves or of a species that is not deemed threatening. A nice analogy would be that of 'a wolf in sheep's clothing'. An interesting example of aggressive mimicry is that employed by female fireflies of the genus Photuris. They are also known as the Feme fatale firefly as the females of this genus mimic the mating signals of other firefly species in order to lure in their male prey. Once the male of the prey species comes in contact he is overpowered then eaten as shown below (Lewis & Crastley, 2008)! There is a secondary benefit to this behavior as the female acquires lucibufagins (defensive steroids) from the males which gives protection against jumping spiders (Eisner et al., 2007).



 References:

Eisner, T, Gomez M A, Hill D E, Smedley, S R, Meinwald J 1997, 'Firefly "femmes fatales" acquire defensive steroids (lucifagins) from their firefly prey', PNAS, vol. 94, pp 9723-9728.

 
 Lewis, S M, Crastley C K 2008, 'Flash Signal Evolution, Mate Choice, and Predation in Fireflies' Annual Review of Entomology, vol. 53, pp 293-321.

 www.britannica.com/EBchecked/topic/9110/agressive-mimicry

 bioteaching.wordpress.com/2012/01/06/fireflies-coleoptera-lampyridae/

This week we shall discover a new type of mimicry: Mullerian mimicry. Mullerian mimicry owes its name to the German naturalist franz Muller .Almost twenty years after Btes brought us Batesian mimicry, Muller offered up a new variation of mimicry in 1878 through his study of insects. Mullerian mimicry describes the event of two or more unpalatable, unrelated species displaying similar warning coulours and patterns. The degree of unpalatability can vary between them i.e. one may be very toxic whilst the other mildly but in order for it to be Mullerian and not Batesian both parties must be unpalatable.

Mulerian mimicry rings often contain a number of different species exhibiting hte same warningcolours. This increases the chance that a predator may try to predate on one of these individuals. After which it should refrain form attacking anything else displaying such a colour scheme.

Mullerian mimicry is not limited to insects. Below are forgs of the genus Dendrobates, collected by Schute et al. (2001). Frogs A-C are of the species Dendrobates imitator, below which are frogs of different species, displaying the sympatic relationship in variation to geographical location:
© The Royal Society


References:

http://www.britannica.com/EBchecked/topic/396909/Mullerian-mimicry

http://inscets.about.com/od/Insect  Defences/f/What-Is-Mullerian-Mimicry.htm

Schulte, R, Summers, K, Symula R 2001, 'Molecular phylogenetic evidence for a mimetic radiation in Peruvianpoison frogs supports a Mullerian mimicry hypothesis', Proceedings of the Royal Society of London B, Vol. 268, pp. 2415-2421, fig. 1.

Batesian mimicry is named after Henry Walter Bates. Henry was an English explorer/naturalist whom surveyed the Amazon Rainforest for over a decade. In this time Bates collected over 100 species of butterfly and noticed whilst sorting them that some superficially resembled others. Bates put forward a hypothesis that this close resemblance was anti-predatory behavior, that one species was mimicking the warning colours but not the toxins of another.

Since Bates' time the concept of Batesian mimicry has evolved to include other aspects such as  palatable moths mimicking the ultrasonic waves of unpalatable species to avoid predation by bats. Studies have shown ( Pope Et al. 2010) that the vocal "hiss" of the Burrowing Owl when in its burrow is a mimic of a rattlesnakes "rattle". This too is a form of Batesian mimicry. Some have argued (Harcombe Et. al. 2001) that when the model is absent that the protection gained by such mimicry breaks down.

References:
 Coss, RG, Owings, DH, Rowe, MP 1986, 'Rattlesnake Rattles and Burrowing Owl Hisses: A case of Acoustic Batesian Mimicry', Ethology, vol. 72, no. 1, pp. 53-71

Harcombe, WR, Pfennig, DW, Pfennig KS 2001, 'Frequency-dependant Batesian mimicry', Nature, vol. 410, pp. 323

http://www.britannica.com/EBchecked/topic/55845/HW-Bates

The purpose of this blog is to examine and explore the use of mimicry and deception in the animal world. Throughout the coming weeks we shall explore how these tactics are used theoughout the animal kindgdom from insects through to mammals encompassing both physiological and behavioral adaptations that have been adopted in order to gain an upper hand in survival whether through predator avoidance, resource gathering or increasing mating opportunities.

This week we shall briefly look at Batesian mimicry. Described by Wallace (1870) Batesian mimicry holds that palatable species look like dangerous species because both are then protected from predation.
A clear example of this is seen in the Viceroy Butterfly, which being palatable to an array of predators including birds, mimic's the warning colour scheme of the toxic Monarch Butterfly and as such lowers the risk of predation.





Wallace, AR 1870  Contributions to the Theory of Natural Selection Macmillan, London.
'Batesian Mimicry', photograph, <http://education-portal.com/academy/lesson/batesian-mimicry-examples-definition-quiz.html#lesson>