10/23/2013 05:06 pm ET

Poorly-Camouflaged Insects Can Set Off A Much Larger Ecological Chain Reaction: Study


An insect's camouflage can have major impacts on its broader ecological habitat, so much so that a poorly-camouflaged one can negatively impact an entire community of insects and the plants that they all live on.

That's according to a recent study published in science journal Current Biology, based on research carried out at the University of Colorado Boulder, which offers some of the most comprehensive evidence yet that natural selection and evolution can drive ecological change.

The scientists focused on a flightless stick insect that lives primarily in Southern California -- the Timema cristinae -- which has evolved to birth two different types of camouflage: one that is all green and camouflages well with broad green leaves and one with a white stripe on its back that blends better with needle-like leaves.

Lead author of the study Tim Farkas and his colleagues found that when they moved the un-striped stick insects to a shrub better suited for the striped stick insects, it affected the ecological system of the entire shrub.

After they were moved, the un-striped stick insects were easier for their predators to spot since they no longer matched their surroundings. As a result, their poor camouflage ended up attracting more scrub-jays and other birds that feast on stick insects and this in turn put the rest of insects living in the shrub in greater jeopardy and the number of living insects as a whole decreased. Some species from the shrub with mismatched insects even disappeared from it completely.

“Our study shows that the evolution of poor camouflage in one species can affect all the other species living there and affect the plant as well,” Farkas said. “It’s intuitive, but also really surprising.”

A commonly-cited example is the English Peppered Moth, which used to be light in color with "peppered" spots until industrialization in the 1950s blackened the trees with coal smoke and made a similarly darker moth more common. A lighter moth against the backdrop of darkened bark had made them easier for predators to spot.

“Studies of how rapid evolution can affect the ecology of populations, communities and ecosystems are difficult to accomplish and therefore rare,” Farkas said. “We’re hoping our research helps biologists to appreciate the extent of dynamic interplay between ecology and evolution, and that it can be used by applied scientists to combat emerging threats to biodiversity, ecosystem services, and food security.”


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