![[my picture]](images/omakuva1b.jpg)
SAMI MERILAITA
Department of Zoology, Stockholm Universitye-mail: sami.merilaita@zoologi.su.se
Many
prey animals use their body colours and patterning to
decrease their risk of predation. Such anti-predator coloration has had
an important role in the history of
the evolution theory: examples of prey coloration constituted some of
the
most convincing piece of evidence for adaptation and the power of
natural
selection during the early days of the theory. In spite of this,
surprisingly
little is still known about how colour patterns of prey manipulate the
perception
of predators and how natural selection shapes the specific appearances
of
prey.
My main interest is how natural selection shapes cryptic coloration (also called concealing coloration, camouflage or crypsis). Prey (and predators) use cryptic coloration to decrease their risk of becoming detected. Because it is such a common adaptation, research on cryptic coloration lets us to understand how the appearances of most animals have been shaped. The two principles for using coloration to decrease the risk of becoming detected that have received most attention in literature are background matching (visual similarity between an animal and its environment) and disruptive coloration (a patterning, which breaks up the characteristic shape of its bearer). At a first glance cryptic coloration may appear a simple adaptation, but actually there still are numerous unanswered questions about how natural selection optimises cryptic coloration under various conditions. For example, what is the best way to visually resemble the environment when the animal is found on several different backgrounds? Or how should an animal choose its colours and patterns to break the shape of its body in the most effective way? How does the visual environment influence the risk of becoming detected? In my research I use both empirical and theoretical approaches. The empirical studies investigate colour pattern in real prey or use predation experiments with artificial prey items and backgrounds, which allow an easy way to manipulate their colours and patterns.
In addition to the evolution of prey appearances I have done some work on sexual selection. Furthermore, I am currently also studying frequency-dependent predation and how the behaviour of individual predators influences maintenance of prey diversity at the community level.
Merilaita, S. & Ruxton, G.D. 2007: Aposematic signals and the relationship between conspicuousness and distinctiveness. Journal Theoretical Biology 245: 268-277. [PDF]
Merilaita, S. & Lind, J. 2006: Great tits (Parus major) searching for artificial prey: implications for cryptic coloration and symmetry. Behavioral Ecology 17: 84-87. [PDF]
Merilaita, S. 2006: Frequency-dependent predation and maintenance of prey polymorphism. Journal of Evolutionary Biology 19: 2022-2030. [PDF]
Merilaita, S. & Tullberg B.S. 2005: Constrained camouflage facilitates the evolution of conspicuous warning coloration. Evolution 59: 38-45. [PDF]
Tullberg, B.S., Merilaita, S. & Wiklund, C. 2005: Aposematism and crypsis combined as a result of distance-dependence: functional versatility of the colour pattern in the swallowtail butterfly larva. Proceedings of the Royal Society of London B 272: 1315-1321. [PDF]
Merilaita, S. & Lind, J. 2005: Background-matching and disruptive coloration, and the evolution of cryptic coloration. Proceedings of the Royal Society of London B 272: 665-670. [PDF]
Merilaita, S. 2003: Visual background complexity facilitates the evolution of camouflage. Evolution 57: 1248-1254. [PDF]
Merilaita, S. & Kaitala, V. 2002: Community structure and the evolution of aposematic coloration. Ecology Letters 5: 495-501. [PDF]
Merilaita, S., Lyytinen, A. & Mappes, J. 2001: Selection for cryptic coloration in a visually heterogeneous habitat. Proceedings of the Royal Society of London B 268: 1925-1929. [PDF]
Merilaita, S. 2001: Habitat heterogeneity, predation and gene flow: Colour polymorphism in the isopod Idotea baltica. Evolutionary Ecology 15: 103-116. [PDF]
Merilaita, S., Tuomi, J. & Jormalainen, V. 1999: Optimisation of cryptic colorations in heterogeneous habitats. Biological Journal of the Linnean Society 67: 151-161. [PDF]
Merilaita, S. 1998: Crypsis through disruptive coloration in an isopod. Proceedings of the Royal Society of London B 265: 1059-1064. [PDF]