Mammalian Mimicry.

For my final post i would like too look at possible cases of mimicry in mammals. Mimicry is found across most orders of the animal kingdom but seems under represented in the mammals. Here i will briefly look at two possible cases of mimicry that occur in Africa.

Firstly we will look at the case of Cheetah cubs mimicking Honey Badgers. The Honey Badger is found throughout Africa and is known for its tenacity, intelligence, fierceness and toughness. The honey badger has loose skin that allows it turn and try and attack predators who have grabbed it from behind. The largest known animal to succumb to a Honey Badger was a blue Wildebeest bull who died after the honey badger lacerated its scrotum. This has also been observed against a male lion. The Cheetah is a large, lightweight cat. They specialize in high speed chases and as such have evolved athletic bodies lacking the bulk of lions and leopards. Cheetah are often pushed off their kill by other predators and will be killed if caught by lions, leopards or spotted hyaenas. They live on the open plains and as such cubs are vulnerable to predation. To counter this the cubs have dark coats with a prominent white crest/mane which is aesthetically similar to the markings of honey badgers (Eaton 1976).


















Cheetah Cub showing crest and dark colouration. 



Honey Badger.

Maned rats are found throughout eastern Africa. They are nocturnal and are possible mimics of two species. It is believed that maned rats mimic Porcupines. They are able to erect a crest of hair along their back to superficially resemble the quills of porcupines. It is also believed that the maned rat may mimic the Zorilla. The Zorilla is a small mustelid that is able to spray a foul smelling liquid from glands near its anus. The maned rat is able to produce a foul smell via gland in its skin but is unable to spray. When threatened it will erect its fur displaying contrasting black and white colours like those of the Zorilla (Brittanica 2014).

Maned Rat.


African Porcupine. 


Zorilla.

References:

Eaton, RL 1976,'A Possible Case of Mimicry in Larger Mammals', Evolution, vol. 30, no. 4, pp. 853-856.

Encyclopedia Britannica 2014, Encyclopedia Britannica, Chicago,viewed 30 April 2014, <http://www.britannica.com/EBchecked/topic/361776/maned-rat>.

Bannister, A, Zorilla amongst grass, Photograph, Arkive, viewed 30 April 2014, <http://www.arkive.org/zorilla/ictonyx-striatus/image-G67846.html>.

Blackwell, P, North African Porcupine Scavenging on Ground, Photograph, Arkive, viewed 30 April 2014, <http://www.arkive.org/north-african-crested-porcupine/hystrix-cristata/>.

Deacon, K 2006, Lophiomys imhausi, Photograph, Wikipedia, viewed 30 April 2014, <http://en.wikipedia.org/wiki/File:Lophiomys_imhausi.jpg>.

Artist unknown, 2006, Honey Badger, Photograph, Wikipedia, viewed 30 April 2014, <http://en.wikipedia.org/wiki/File:Honey_badger.jpg>.

Artist unknown, 2009, 'Cheetah Cub', Photograph,  The Milgis Trust, Nairobi, Kenya, viewed 30 April 2014, <http://milgistrust.wildlifedirect.org/2009/01/07/the-cheetah-cub-is-fighting-fit/>.

Taking mimicry to the next level?

First discovered in the mid 1980's the Mimic Octopus (Thaumoctopus mimicus) was only officially described in 2005. The mimic octopus is so novel that a new genus was created in order to classify it (Norman & Hochberg 2005). Found initially in Indonesia specimens have been found as far away as New Caledonia and recently at Lizard Island in Australia (Cocker 2013). The mimic octopus' arm span reaches a maximum size of approximately 60 cm. They are mainly found in muddy inter-tidal/estuarine sand flats where they actively explore burrows made by small fish and crustaceans on which they feed (marinebio 2013).
What makes the mimicry of T. mimicus so unique is that it is able to mimic not only the shapes but behaviors of a multitude of species and modify its mimicry to a perceived threat. Norman, Finn & Tregenza (2001) noted that when harassed by territorial damselfish the mimic octopus would place six arms down  hole and display its other two with distinct black and white banding. Moving the arms in such a manner as to mimic a banded sea-snake, which happens to prey on damselfish.
 Figure 1. `Mimic octopus’: (a) sentinel state in mouth of burrow; (b) normal foraging colour pattern; (c) Flatfish mimicry; (d) Flatfish model, banded sole (Zebria ssp.); (e) lion-fish mimicry; (f) lion-fish model (Pteroissp.); ( g) sea-snake mimicry; (h) sea-snake model, banded sea-snake (Laticauda sp.). Photographs by M. Norman and R. Steene.


The mimic octopus is also reported to mimic jellyfish, sand anemones as well as the background colour and texture however the mimicry of other creatures is subjective as it is human interpretation that is classifying it (Norma, Finn & Treganza 2001).
It is hoped that the relatively unexplored estuarine environments of the tropics may yield other mimic species.

References:

Cocker, D 2013,'Documentation of the mimic octopus Thaumoctopus mimicus in the Great Barrier Reef, Australia', Marine Biodiversity Records, vol. 6, no. 14, pp. 1-2.

Norman, M Finn, J Tregenza, T 2001,'Dynamic mimicry in an Indo-Malayan octopus', Proceedings of the Royal Society of London, vol. 268, no. 1478, pp. 1755-1758.

Norman, M Hochberg, F 2005,'The "Mimic Octopus" (Thaumoctopus mimicus n. gen. et sp.), a new octopus from the tropical Indo-West Pacific (Cephalopoda: Octopodidae), Molluscan Research, vol. 25, no. 2, pp. 57-70.

MarineBio 2010, MarineBio Conservation Society, California, viewed 24 May 2014, <http://marinebio.org/species.asp?id=260>.

Clever Katydid

The Spotted Predatory Katydid or Chlorobalius leucoviridis is a large aggressive  species found throughout  the arid interior of Australia that makes use of mimicry to catch its prey.
Images copyright D. Marshall & K. Hill.

This species feeds on a wide range of prey items including flies, grasshoppers, cicada's and other katydid species . Rentz (1995) found that prey are held in the long spiny forearms and disabled via a bite to the throat. What is interesting about this species is its ability to successfully mimic the female response call to male Cicada's, luring him within range to be preyed upon. Marshal & Hill (2009) found that the Katydid was able to mimic the species-specific wing clicks produced by sexually receptive females in response to males. Furthermore they also mimic the Cicada's visually with a series of body jerks. This combination of both visual and auditory mimicry has led to the Katydid becoming a very successful predator. The katydid however only responds to the calls of cicadas during daylight. Male cicadas are vocal throughout the evening but the Katydids ignore the calls of their prey after dark and instead focus on their own intraspecies communication
 Interestingly Marshall & Hill (2009) found that the Katydid will respond to the calls of male Cicada species to which they have never been exposed- that is species that do not occur in their geographical area. They hypothesis that the mechanism that has driven the Katydids ability to mimic is hardwired to species that use a duet calling system.

References:
Marshall, D Hill, K 2009, 'Versatile aggressive mimicry of cicadas by an Australian predatory katydid', Plos One, vol. 4, no. 1, pp. e4185.

Rentz, D 1995, 'Do the spines on the Legs of Katydids Have a Role in Predation? (Orthoptera: Tettigoniidae: Listroscelidinae)', Journal of Orthoptera Research, vol. 08/1995, no. 4, pp. 199-200.

Marshall, D Hill, K 2009, 'Katydid Predation', Photo, Encyclopedia Of Life, viewed 17 May 2014. <http://eolspecies.lifedesks.org/node/3522>

Horsfield's Bronze-Cuckoo (Chalcites basalis) are found throughout Australia. These birds are brood parasites- that is they parasite the nest of another species of bird in order for the host species too raise their young. Horsefields Bronze-Cuckoo's favor the nests of  Fairy Wrens and Thornbills (Brooker, Brooker 1989). The Cuckoo's have evolved many strategies to aid them in their deceptions. The eggs of Cuckoo's superficially resemble the eggs of their host species making it difficult for hosts to detect the intruder.


Female Cuckoo's lay their eggs late in the developmental stage so that their chick is the first too hatch. Once hatched the young set about evicting the other eggs from the nest so that they can receive the sole attention of the host parents. Research by Langmore, Maurer, Adcock and Kilner (2008) found that  Horsfield's Bronze-Cuckoo chicks are born with the ability to mimic two species. Initially they will sing the begging cry of the Fairy-Wren. Langmore et. al. (2008) believe that the chick will change song due to environmental cue's and hypothesized that hunger was the driving factor. They found that  the chicks would switch form singing the Superb Fairy-Wren cry to a melody of cries, eventually whittling away notes and sounds that did not elicit a response form the host until they match the appropriate cry, in this case the Buff-Rumped Thornbill.This ability to mimic not only the hosts eggs superficially but also the cry of their young has led too the success of Cuckoo's globally.

On a side note the Cuckoo's do not have it all their own way. The relationship between the Horsfield's Bronze-Cuckoo and the Superb Fairy Wren is great example of the evolutionary arms race of species. Research by Langmore, Hunt and Kilner (2003) found that Super Fairy-Wrens abandoned a cuckoo chick 38% of the time. They discovered that some female Superb fairy-Wrens sing a special song too their developing eggs which contains a hidden 'key' note. This key note is incorporated into the begging cry of the chicks. The Cuckoo chicks not having heard the song during development miss out on this key note and as such are recognized by the parents as an intruder and are subsequently abandoned.

References:

Brooker, M Brooker, L Rowley, I 1988, 'Egg deposition by the bronze-cuckoos Chrysococcyx basalis and Ch. ludicus' Emu 88, pp. 107-109.

Langmore, N Hunt, S Kilner, R 2003, 'Escalation of coevolutionary arms race through host rejection of brood parasitic young', Nature 422, 157-160.

Langmore, N Golo, M Adcock, G Kilner, R 2008,'Socially Acquired Host-Specific mimicry and the Evolution of Host Races in Horsefield's Bronze-Cuckoo Chalcites basalis', Evolution  62, pp. 1689-1699.

Artist unknown, 'Egg comparisons', Photograph, BBC, viewed 10th May 2014, <http://news.bbc.co.uk/earth/hi/earth_news/newsid_8645000/8645158.stm>

Specialised Spiders!

This week we shall look at a very special group of spiders- Bolas Spiders! Bolas spiders hunt in a very unique manner- they don't create a traditional web, rather they stay on a single strand of silk spread across two points. They then use another strand of silk with a sticky 'globule' at the end. Bolas spiders mimic the pheromones of female moths in order to attract the males of that species close enough so that they may be caught with the bolas, which is swung around by the spider. The Spiders detect prey by eyesight as well as the sound of wings in flight. They will attempt to catch anything that flies close enough even if it is not their targeted pheromone species. Research by  Haynes et al (2002) Found that the American bolas spider is able to mimic the pheromones of two moth species- the smoky tetanolita: Tetanolita mynesalis and the bristly cutworm: Lacinipolia renigera. These two species are active at different times of the evening and the spider is able to alter the pheromones it omits to target each species at these different time periods. Cutworms are actively hunted till approximately 10:30 pm. Tetanolita generally become active from 11 pm and Haynes et al (2002) found that the bolas spider switches the pheromones it produces throughout the night in order too target each species individually.

Image: Haynes, K and Yeargen, K.

If you wish too see a Bolas Spider in action follow this link: https://www.youtube.com/watch?v=EWec266Lo3Q.

References:
Haynes, K Gemeno, C Yeargan, K Millar, J Johnson, K 2002, 'Aggressive chemical mimicry of moth pheromones by a bolas spider: how does this specialist predator attract more than one species of prey?', Chemoecology, vol. 12, pp. 99-105.

Haynes, K Yeargen K,  'Bolas Spider', Photo, Real Monstrosities, viewed 04 May 2014, <http://www.realmonstrosities.com/2012/08/bolas-spider.html>

From here on out I'll be highlighting what I find to be interesting cases of mimicry/deception employed by animals. This week we shall look at the mourning cuttlefish (Sepia plangon). The males of this species use visual deception against there rivals in order to gain an advantage during the mating season. The male will display his courtship patterns to a receptive female on one half of his  body whilst displaying female patterns on the other half in response to the presence of a rival in order to prevent disruption to his courtship, however if two females are present this deception is not used. Research by Brown, Garwood & Williams (2012, p.730) found that this tactic was employed 39% of the time that a rival male was present during courtship.


Figure 1. form Brown, Garwood & Williams (2012, p.731) shows Female (F) Male (M) and direction of rival male (A).

References:
Brown, C. Garwood, M. Williams, J 2012 "It pays to cheat: deception in a cephalopod social signalling system", Biology Letters, vol. 8, no. 5, pp. 729-732.

This week we shall continue the theme of aggressive mimicry and look at a rather interesting case. Whilst most animals employ aggressive mimicry by mimicking another animal the orchid mantis does so by mimicking the orchid flower. This is reported to be the only such case recorded so far. Found in Malaysia the Orchid Mantis uses flowers as a base from which to ambush mainly hymenopteran prey. Research into the orchid mantis (O'Hanlon, Holwell, Herberstein 2014) has shown that pollinators actually visit flowers where a mantis is positioned 30% more than flowers without mantis. The reason for this is still unknown. The researchers also discovered that mantis' sitting away form the flowers are able to attract pollinators at higher rates than the flowers themselves.


© Thomas Marent

References:
O'Hanlan, J C, Holwell, G I, Herberstein M E 2014, 'Pollinator Deception in the Orchid Mantis', The American Naturalist, vol. 183, no. 1, pp. 126-132.

Marent T "n.d", 'Mantis on Flower', Photograph, National Geographic, viewed 6 April 2014, <http://newswatch.nationalgeographic.com/files/2013/08/orchid-mantis.png>.