Thanks for reading!

Over the last 13 weeks I have covered a diverse selection of animals displaying mimicry and deception, which I hope you have found entertaining and insightful. My posts only show an infinitesimally small array of the amazing displays found within the animal kingdom.

For more examples of extraordinary mimicry and deception visit this National Geographic page and see if you can spot the mimics.

Thanks for reading!

Sleeping Cichlids

Last week I posted about a fish that posed as a leaf in the bottom of lakes and rivers (Leaf Fish), this week’s animal poses as something slightly more morbid. 

The Sleeping Cichlid (Nimbochromis livingstonii)

Unlike the leaf fish (who’s main aim was to remain undetected by prey), the Central American Sleeping Cichlid (Nimbochromis livingstonii) positions itself on and sometimes half emerged in the sand of river-beds feigning death, in order to attract prey. Opportunistic passers-by see the “corpse” and go in for an easy meal. Once the prey gets close enough the sleeping cichlid attacks
(Tobler, 2005; Chakrabarty, 2005).

A Sleeping Cichlid (Nimbochromis livingstonii) "sleeping" on the sandy river bed, feigning death to lure in unsuspecting prey (YouTube, 2015).

This deceptive behaviour allows the sleeping cichlid to catch prey unaware and have the benefit of surprise.

However! Once in a while, a larger fish may try to have a nibble, which the sleeping cichlid would have no chance of attacking and dart away speedily (Tobler, 2005).

References:

Chakrabarty, P. 2005, "Testing Conjectures about Morphological Diversity in Cichlids of Lakes Malawi and Tanganyika", Copeia, vol. 2005, no. 2, pp. 359-373.

Tobler, M. 2005, "Feigning death in the Central American cichlid Parachromis friedrichsthalii", Journal of fish biology, vol. 66, no. 3, pp. 877-881.


 The sleeping cichlid by Gabriel, 2010
Accessed: www.malawi-cichlides.com

Nimbochromis livingstonii nakatenga by Genepy Power, 2010

Accessed: https://www.youtube.com/watch?v=LJMu1dA2PTk

 

Leafy Sea Dragons

Endemic to the waters of Southern Australia, Leafy sea dragons (Phycodurus eques) belong to the Syngnathidae family (which includes seahorses, pipefish, and weedy seadragons, Phyllopteryx taeniolatus, the leafy sea dragons closest relative). These majestic creatures have leaf like appendages (hence the name), which aid in camouflage, and grow up to 43cm in length (Larson et al. 2014).

A leafy sea dragon pictured in the wild (Photograph by George Grall)

Unlike their reddish coloured cousins (weedy sea dragons), leafy sea dragons are typically yellow with olive-brown specked appendages. This colouration helps the sea dragon to blend into the kelp and seaweed formations they live amongst (Larson et al. 2014).

Though they do maintain sanctuary hidden amongst the underwater forests, leafy sea dragons do have a defence mechanism in the form of long spines located on the side of their bodies. Leafy sea dragons are incredibly vulnerable to population disruption with ever-increasing pollution and habitat degradation, as well as harvesting for aquariums, low genetic diversity and dispersal, and small home ranges unfortunately leading to population fragmentation (Larson et al. 2014).

Watch the video below to see the leafy sea dragon floating majestically amongst aquatic vegetation.

WATCH: Leafy Sea Dragon, South Australia - Phycodurus eques 

 

References:

Larson, S., Ramsey, C., Tinnemore, D. & Amemiya, C. 2014, "Novel Microsatellite Loci Variation and Population Genetics within Leafy Seadragons, Phycodurus eques", Diversity, vol. 6, no. 1, pp. 33-42.

National Geographic, 2015. “Leafy and Weedy Sea Dragon (Phycodurus eques, Phyllopteryx taeniolatus)”. Accessed 19^th May 2015 http://animals.nationalgeographic.com.au/animals/fish/sea-dragon/

Leaf Fish

In the animal world, its kill or be killed. Many animals develop weaponry or aggressive behaviour to defend them selves against predators. But not the leaf fish!

Leaf fish are a diverse group found in Asia (Nandidae), South America (Polycentridae) and Africa (Polycentropsis abbreviata; Barlow, 1967; Catarino & Zuanon, 2010).

In this weeks blog post I will focus on the South American species observed in and around the Amazon basin.

WATCH: Build for The Kill – Leaf Fish

These amazingly deceptive fish camouflage themselves into streams, lakes and rivers by mimicking leaves. With a laterally compressed body shape, mottled patterns and colours, leaf fish remain hidden from predators. Their camouflage efforts even go as far as forming an extended filament in the lower jaw to resemble a petiole (a must-have for any leaf related costume). Seemingly harmless, the fish can go completely undetected by prey until they strike with their large protractile mouths (Barlow, 1967; Catarino & Zuanon, 2010).

References:

Barlow, G.W. 1967, "Social Behavior of a South American Leaf Fish, Polycentrus schomburgkii, with an Account of Recurring Pseudofemale Behavior", American Midland Naturalist, vol. 78, no. 1, pp. 215-234.

Catarino, M.F. & Zuanon, J. 2010, "Feeding ecology of the leaf fish Monocirrhus polyacanthus (Perciformes: Polycentridae) in a terra firme stream in the Brazilian Amazon", Neotropical Ichthyology, vol. 8, no. 1, pp. 183-186.

Leaf Insects

I’m not going to talk about how a leaf insect mimics a leaf, that would be too obvious! Instead I’m going to discuss the nature in which Spiny Leaf insects (Extatosoma tiaratum) lay their eggs and deceive ants in the process. 

A female adult spiny leaf insect (Extatosoma tiaratum) displayed on a leaf (AUSECO, 2008)

Eggs produced by leaf insects resemble seeds often from a mixture of toxic and non-toxic plants (eg. Lupins sp. and legumes respectively). A capitula like structure formed on the crown of the egg is lipid rich and a favourite food of ants. The ants carry the egg to their nests where it is protected from birds and other predators such as wasps. Once the egg has hatched, the first instar nymph stage resembles the larvae of ants (documented in Leptomyrmex ants by Key, 1970) facilitating movement from the nest to the surface without detection. This deception allows for increased survival of leaf insects eggs, where on the surface they would have been predated by birds. Shelomi (2011) found that quails (Coturnix japonica) and chickens (Gallus gallus domestica) eagerly consume the eggs produced by spiny leaf insects, but unlike most plant seeds the eggs did not survive digestion. Just one in nearly a thousand eggs remained intact after consumption by these bird species, providing strong observations that without the protection by ants in their nests spiny leaf insect eggs would not survive long enough to hatch, detrimental to the population of the species (Key, 1970; Sellick, 1997; Shelomi, 2011).

WATCH: the interaction between ants and spiny leaf insect eggs as shown by David Attenborough 

References:

Key, J. 1970. “Phasmatodea”, CsiRo (ed.) the insects of Australia. Melbourne University Press, Melbourne, Australia pp. 348-359

Sellick, J. 1997, "The range of egg capsule morphology within the phasmatodea and its relevance to the taxonomy of the order", Italian Journal of Zoology, vol. 64, no. 1, pp. 97-104.

Shelomi, M. 2011, "Phasmid Eggs Do Not Survive Digestion by Quails and Chickens", Journal of Orthoptera Research, vol. 20, no. 2, pp. 159-162.

Image:  

AUSECO, 2008.  http://www.auseco.com.au/index.asp?pagename=eco+updates+phasmids

Accessed: 10th May 2015

Vocal Mimicry: Selection

The male superb lyrebird (Menura novaehollandiae) uses vocal displays when encountering rival males or before mating. 70% of the superb lyrebirds repertoire consists of imitations from approximately 20 different species of neighbouring birds (Dalziell & Magrath, 2012). As the receivers are either rival males or potential mates, Dalziell & Magrath (2012) strongly suggest that the mimetic vocalizations are a sexually selected trait.

Because of this, large repertoires may be more favourable by selection than mimicry, as a wider variety of songs give the superb lyrebird increased mate choice and territorial defence. However, obtaining a large repertoire would require mimicry as a shortcut (Dalziell & Magrath, 2012).

As I’ve already mentioned in my previous post (Vocal Mimicry: Accuracy vs Versatility) superb lyrebirds are highly accurate mimics. Coleman and colleagues (2007), in their study of satin bowerbirds (Ptilonorhynchus violaceus), suggest that high accuracy is driven by female preferences in complex mating displays. A correlation can be made about mating success and accuracy, as modification of vocal motor patterns, and learning and refinement of displays as a juvenile is required for mimetic accuracy (Coleman et al. 2007).

To date, only two studies have been successfully conducted on the mimetic accuracy of this species, so conclusive information is limited, but not unknown.

Dalziell & Magrath (2012) found that there is strong selection favouring accuracy rather than large repertoires in order for mating success, and that a species can decipher signal structure and contextual learning to distinguish between the model and imitations.

Quality over quantity.

References:

Coleman, S.W., Patricelli, G.L., Coyle, B., Siani, J. & Borgia, G. 2007, "Female preferences drive the evolution of mimetic accuracy in male sexual displays", Biology Letters, vol. 3, no. 5, pp. 463-466.

Dalziell, A.H. & Magrath, R.D. 2012, "Fooling the experts: accurate vocal mimicry in the song of the superb lyrebird, Menura novaehollandiae", Animal Behaviour, vol. 83, no. 6, pp. 1401-1410.

Vocal Mimicry: Accuracy vs Versatility

It’s the age-old question of quality or quantity. Is it more advantageous to have a large repertoire of songs of average quality or a few high quality songs accurate enough to fool even the best receiver? Continuing on from my last post (Vocal Mimicry), I will discuss the accuracy of mimicry versus versatility and having a large portfolio of songs in lyrebirds (Menuridae).

Dalziell & Magrath (2012) measured the superb lyrebirds (Menura novaehollandiae) ability to successfully deceive grey shrike-thrush (Colluricincla harmonica). They did this by using playback experiments of the imitated shrike-thrush song and the actual song, and also by measuring the acoustic properties of the two. 

When the shrike-thrush heard the superb lyrebirds mimetic song, they reacted strongly as though it was their own. However, when the mimetic song was played alongside the actual song, the shrike-thrush still approached the speakers where the audio was playing but were not as convinced (Dalziell & Magrath, 2012).  

Image: The Superb lyrebird (top) known to mimic the songs of the Grey shrike-thrush (bottom) in order to increase availability to resources such as food and mates.

The acoustic properties of the mimetic song were amazingly similar to those of the actual song, where the lyrebird achieved the correct structure and complexity. However the lyrebird failed to display the same repetition of element types within the song, and instead emulated their own natural singing style (Dalziell & Magrath, 2012). 

In my next post I will discuss the selection for accuracy and versatility, and which is favoured more by selection. 

References:

Dalziell, A.H. & Magrath, R.D. 2012, "Fooling the experts: accurate vocal mimicry in the song of the superb lyrebird, Menura novaehollandiae", Animal Behaviour, vol. 83, no. 6, pp. 1401-1410.

 

 Photos:

Grey shrike-thrush. Image by Richard Hall www.richardhallphotography.com

 Accessed:  12th April 2015

Superb lyrebird. Image BrocPhoto www.birdforum.net

Accessed: 12th April 2015