To quiver or to shiver: Explaining warning signal diversity in wood tiger moths

Feb 11, 2013

A central question in evolutionary biology is what causes the diversity of appearance seen in animals of the same species? Diversity is the raw material evolution has to act on, and this is why it is important to study the processes causing diversity. However, organisms that possess warning signals telling that they are unpalatable are not really expected to have very diverse forms of coloration. Such organisms are known as "aposematic," and a similar looking coloration which acts as a warning signal is a way to make sure that potential predators will recognize and avoid them. It is especially interesting to take a look at the cause of diversity in the appearance of aposematic species because it is not predicted.

To probe mechanisms that cause diversity in the appearance of wood tiger moths, researchers from the Centre of Excellence in at the University of Jyväskylä, Finland, studied how melanization in aposematic male wood tiger moths varied across Europe. They observed that male wood tiger moths were darker in the Alps and also in Northern Finland. Some previous work on other species indicated that more melanized butterflies and moths might have better ability to warm up more efficiently.

"Warming up in places like the Alps and Northern Finland is probably pretty important if you are a trying to fly around to find the females," says researcher Robert Hegna.

Based on the evidence of the moth's appearance and temperature in places where moths were more melanized together, the researchers hypothesized that the different benefits promoting more was traded of in cooler places and more in warmer places.

After completing laboratory-based thermoregulation studies and field-based predation experiments, researchers concluded their hypothesis was correct. They found that the differences in how melanized the moths look were linked to two processes, both acting on the same trait in a "tug-of-war" competition. Such a phenomenon is known as a "trade-off". Moths with less melanin were more protected against predators probably because their bright colors were more conspicuous to predators, while moths with more melanin were less protected from predators. However, moths with more melanin could warm up more quickly, which might enable them to be out looking for females more often in cooler weather than their less melanized counterparts. This would explain why moths in the Alps tended to be more melanized than many of the in Finland and shows that diversity in appearance can potentially be caused by complications.

Explore further: Male monkey filmed caring for dying mate (w/ Video)

add to favorites email to friend print save as pdf

Related Stories

Camouflage of moths: Secrets to invisibility revealed

Jul 31, 2012

Moths are iconic examples of camouflage. Their wing coloration and patterns are shaped by natural selection to match the patterns of natural substrates, such as a tree bark or leaves, on which the moths rest. ...

Fossil moths show their true colors

Nov 15, 2011

The brightest hues in nature are produced by tiny patterns in, say, feathers or scales rather than pigments. These so-called "structural colors" are widespread, giving opals their fire, people their blue eyes, ...

Finding genetic changes behind moths' coloration

Apr 17, 2011

During the Industrial Revolution in 19th-century England, black moths started appearing - because they blended in better on pollution-darkened tree trunks than did normal, speckled moths. Now scientists are ...

Fossil moths reveal their true colors

Oct 12, 2011

Moths dead for 47 million years are again showing their true colors. For the first time, scientists have reconstructed the colors of an ancient fossil moth. The findings detailed not just a few spots of color, ...

ZooKeys opens the gates to America's moth diversity

Feb 06, 2013

Since its inception in 2009, the "Contributions to the systematics of New World macro- moths" series in ZooKeys has been playing an important role in publishing taxonomic changes and new discoveries concerning m ...

Recommended for you

Male monkey filmed caring for dying mate (w/ Video)

18 hours ago

(Phys.org) —The incident was captured by Dr Bruna Bezerra and colleagues in the Atlantic Forest in the Northeast of Brazil.  Dr Bezerra is a Research Associate at the University of Bristol and a Professor ...

Orchid named after UC Riverside researcher

Apr 17, 2014

One day about eight years ago, Katia Silvera, a postdoctoral scholar at the University of California, Riverside, and her father were on a field trip in a mountainous area in central Panama when they stumbled ...

In sex-reversed cave insects, females have the penises

Apr 17, 2014

Researchers reporting in the Cell Press journal Current Biology on April 17 have discovered little-known cave insects with rather novel sex lives. The Brazilian insects, which represent four distinct but re ...

Fear of the cuckoo mafia

Apr 17, 2014

If a restaurant owner fails to pay the protection money demanded of him, he can expect his premises to be trashed. Warnings like these are seldom required, however, as fear of the consequences is enough to ...

User comments : 0

More news stories

Researchers successfully clone adult human stem cells

(Phys.org) —An international team of researchers, led by Robert Lanza, of Advanced Cell Technology, has announced that they have performed the first successful cloning of adult human skin cells into stem ...

Male monkey filmed caring for dying mate (w/ Video)

(Phys.org) —The incident was captured by Dr Bruna Bezerra and colleagues in the Atlantic Forest in the Northeast of Brazil.  Dr Bezerra is a Research Associate at the University of Bristol and a Professor ...

Researchers develop new model of cellular movement

(Phys.org) —Cell movement plays an important role in a host of biological functions from embryonic development to repairing wounded tissue. It also enables cancer cells to break free from their sites of ...

Impact glass stores biodata for millions of years

(Phys.org) —Bits of plant life encapsulated in molten glass by asteroid and comet impacts millions of years ago give geologists information about climate and life forms on the ancient Earth. Scientists ...