"The greatest amount of life can be supported by great diversification of structure." Charles Darwin

Thursday, March 26, 2015

Luminous arthropods

The phenomenon of bioluminescence has evolved at least three times within arthropods. These known luminescent arthropods include fireflies, Sierra luminous millipedes, and the South American luminous giant cockroaches (Lucihormetica luckae). Except in fireflies, the molecular mechanisms for bioluminescence in arthropods remain largely unknown. This will be a very interesting area of research in the near future.

Lucihormetica luckae (Blaberidae) from Ecuador. It is still debatable whether these South American giant cockroaches are truly luminescent or instead just fluorescent, but it's interesting to note that the producers of the Disney movie WALL-E might have borrowed the idea from this organism to create the image of Eve.

Our lab also had a lot of fun catching some local fireflies in a night field trip last fall.

There is also an interesting article recently appearing on National Geographic about bioluminescence in diverse lineages of life (click the link below).

Saturday, March 14, 2015

General Relativity turns 100

Science magazine celebrates the 100th anniversary of Einstein's general theory of relativity, a theory that forever changed our view of the universe.
See papers from this special issue:

Friday, March 13, 2015

Scientists figured out how chameleons change colors

When we consider colors seen in animals and plants, we would assume they are due to the presence of pigment molecules that absorb light at different wave lengths. For example, plants are green because Chlorophyll absorbs strongly the blue and red portion of the visible light spectrum, and leaves out the green. It is also known that some animals can rapidly control their body color to blend in or stand out from their environmental background colors.

Cuttlefish represent a well-known case deep from the ocean, where they can alter body color to camouflage themselves, attract mates, or warn off potential predators. This is achieved by actively controlling several groups of blue, red, yellow, brown, and black pigmented chromatophores. The pigmented chromatophores can be folded when retracted, and the collective action of these chromatophores then give rise to the remarkable color patterns on the skin.

The mechanism for color change in cuttlefish has been thought as a general mechanism for color and pattern change seen in animals. Until recently have scientists revealed a new mechanism in chameleons for controlling body colors without using pigments. It turns out that chameleons does it through a clever way of manipulating reflection.  Rather than moving pigments around in the cell, chameleons actually use a tunable lattice of guanine crystals to reflect certain wavelengths of light.  Its like the iridescence of a blue morpho butterfly, but customizable! Here is a nice viedo clip introducing this fascinating study:

The original research paper can be found here: