Study confirms Darwinian idea of speciation

April 6th, 2008 - 4:50 pm ICT by admin  

New York, April 6 (IANS) In the first experiment of its kind conducted in nature, a biologist has come up with strong evidence for one of Charles Darwin’s cornerstone ideas - adaptation to the environment accelerates the creation of new species. After studying walking-stick insects in southern California, University of British Columbia evolutionary biologist Patrik Nosil concluded that “the more ways a population can adapt to its unique surroundings, more likely it will ultimately diverge into a separate species”.

Stick insects cannot fly and live and feed on their host plants. Different “eco-types” of walking-stick insects are found on different plants and exhibit different colour patterns that match the features of their host plants.

For example, insects of the cristinae eco-type, which feed on plants with needle-like leaves, have a white line along their green bodies.

“A single adaptive trait such as colour could move a population towards the process of forming a new species, but adaptation in many traits may be required to actually complete the formation of an entirely new species,” said Nosil.

His study, titled “Ecological Niche Dimensionality and the Evolutionary Diversification of Stick Insects”, has been published in the journal PLoS One.

By displacing some eco-types away from their customary host plants and protecting others from their natural predators, Nosil found that colour pattern alone could initiate speciation, but natural selection on additional traits were required to complete the speciation process.

“As far as advancing Darwin’s theory that natural selection is a key driver of speciation, this is the first experiment of its kind done outside of a lab setting. The findings are exciting,” said Nosil.

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