Background Matching Animals

As discussed last week, background matching or concealing colour, as it is also known, is the relationship between the organism and its background (Dimitrova & Merilaita, 2010). An animal must have an appearance matching one specialised environment in, “Colour, lightness or pattern” (Merilaita, 2010). Last week I touched on the importance of an organism using background matching to avoid predators and the significance this plays in the evolution and natural selection of specific species (Dimitrova & Merilaita, 2010). This week I would like to show you some of these amazing camouflaging evolutions. 

I would like to start with Crab spiders (Thomisus onustus), which colour matches with flowers (Thery & Casas, 2002). They do this not only to hide from predators, such as birds, but also from their prey (which can be called aggressive mimicry), which are various pollinating insects including; bees, wasps and flies. Thery & Casas (2002) used spectroradiometry (a way of measuring light energy at different wavelengths) to assess if the spiders really were hidden from the vision of their prey and predator. Amazingly enough, the spiders were well camouflaged on several of the flower species for birds and insects vision.

Crab Spider 

Another example of general colour resemblance is the Eastern Garter Snake, Thamnophis sirtalis sirtalis Ryerson, 2017). Not only did Ryerson (2017) observe it in a field using its colouration, he also stated that its head wobbled slightly while the rest of its body stayed still. Ryerson (2017) hypothesised that it was in fact using this as an additional camouflage technique to copy the motion of the grass it was in called behavioural camouflage.

 Eastern Garter Snake

The last example of background colouration is the Ussurian Tube-Nosed Bats (Murina ussuriensis) found in parts of Russia, Korea and Japan (Hirakawa & Kawai, 2006). This small, dark brown furred bat roosts in buildings, tree cervices, bark and has even been discovered in snow (Fukui et al., 2012). It has been found to roost on lower branches than other bats and is believed this is due to its ability to camouflage with the foliage and dead branches (Hirakawa & Kawai, 2006).  

Ussurian Tube-Nosed Bat holding onto a tree trunk 

Ussurian Tube-Nosed Bat Roosting in dead leaves (Hirakawa & Kawai, 2006)

References

Dimitrova M., & Merilaita S. (2010). Prey concealment: visual background complexity and prey contrast distribution. Behavioural Ecology. 21(1), 176-181.

Fukui D., Hill D., & Matumura S. (2012). Maternity Roots and Behaviour of the Ussurian Tube-Nosed Bat (Murina ussuriensis). BioOne. 14(1), 93-104.

Hirakawa H., & Kawai K. (2006). Hiding Low in the Thicket: Roost Use by Ussurian Tube-Nosed Bats (Murina ussuriensis). BioOne Complete. 8(1), 263-269.

Merilaita S. (2003). Visual Background Complexity Facilitates the Evolution of Camouflage. Evolution. 57(6), 1248-1254.

Ryerson W. (2017). A Novel Form of Behavioural Camouflage in Colubrid Snakes. ProQuest. 105(2), 363-367.

Thery M., & Casas J. (2002). Predator and Prey Views of Spider Camouflage. Brief Communications. 415(68), 133.