Friday, October 28, 2011

Butterfly background Images

Artistic depictions of butterflies have been used in many cultures including Egyptian hieroglyphs 3500 years ago.
Host plants often have toxic substances in them and caterpillars are able to sequester these substances and retain them into the adult stage. This helps making them unpalatable to birds and other predators. Such unpalatibility is advertised using bright red, orange, black or white warning colours. The toxic chemicals in plants are often evolved specifically to prevent them from being eaten by insects. Insects in turn develop countermeasures or make use of these toxins for their own survival. This "arms race" has led to the coevolution of insects and their host plants.
Many of the tropical butterflies have distinctive seasonal forms. This phenomenon is termed seasonal polyphenism and the seasonal forms of the butterflies are called the dry-season and wet-season forms. How the season affects the genetic expression of patterns is still a subject of research. Experimental modification by ecdysone hormone treatment has demonstrated that it is possible to control the continuum of expression of variation between the wet and dry-season forms. The dry-season forms are usually more cryptic and it has been suggested that the protection offered may be an adaptation. Some also show greater dark colours in the wet-season form which may have thermoregulatory advantages by increasing ability to absorb solar radiation.
The idiom "butterflies in the stomach" is used to describe a state of nervousness.
Butterflies are characterized by their scale-covered wings. The coloration of butterfly wings is created by minute scales. These scales are pigmented with melanins that give them blacks and browns, but blues, greens, reds and iridescence are usually created not by pigments but the microstructure of the scales. This structural coloration is the result of coherent scattering of light by the photonic crystal nature of the scales. The scales cling somewhat loosely to the wing and come off easily without harming the butterfly.

Butterfly background Images
Butterfly background Images
Butterfly background for
Butterfly background for
Purple Butterfly background by
Purple Butterfly background by
Save Purple Floral Butterfly
Save Purple Floral Butterfly
Butterfly Background by
Butterfly Background by
Re Butterfly Background
Re Butterfly Background
Desktop Wallpaper � Gallery
Desktop Wallpaper � Gallery
Blue Butterfly Background
Blue Butterfly Background
Butterflies Backgrounds
Butterflies Backgrounds
Striped Butterfly Background
Striped Butterfly Background
City Love Butterfly
City Love Butterfly
Butterfly Background Bleeding
Butterfly Background Bleeding
Butterfly Background of Pastel
Butterfly Background of Pastel
Black Butterfly Background
Black Butterfly Background
butterfly background
butterfly background
Tiled butterfly background
Tiled butterfly background
M Lg Butterfly Background
M Lg Butterfly Background
Stars Butterfly Swirls Designs
Stars Butterfly Swirls Designs

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