Why female water fleas change their fashion trends every season

May 4th, 2010 - 3:53 pm ICT by ANI  

Washington, May 4 (ANI): While studying fashion trends for water fleas, Swedish researchers have uncovered the mystery behind why do females change the way they look each season while males look the same all year round.

Touted as one of the world’s trendiest crustaceans, water fleas have the ability to change their appearance to suit their surroundings and the season.

This may involve, for example, donning new accessories: water fleas can grow long antennae, a larger back hump or a new “cap” of varying sizes.

Researchers at the University of Gothenburg, Sweden, who studied water fleas in the Orekilsalven river basin believe these accessories to be the water fleas’ way of reducing the risk of being caught and eaten.

And remarkably water fleas in different lakes follow different trends.

For example, high up in the Orekilsalven water system, the females have been wearing small round caps teamed with fairly large bodies, while their counterparts further down in the system have gone the other way - larger caps but smaller bodies.

Hans Lord has offered an explanation in his thesis-a large cap protects the water fleas from small invertebrate predators, as it makes it harder for these predators to catch and hang on to them.

Smaller bodies, in turn, are the water fleas’ way of adapting to predatory fish, which rely on their sight to locate their prey.

The combination of a small body and a large cap is a compromise- the smaller body reduces the risk of being spotted by a fish, while the large cap (which is transparent and therefore invisible to the fish) offers protection from invertebrate predators.On the contrary, males don’t seem at all bothered by current trends.

And the researchers attributed this with reproduction- given that the females carry the offspring, a dead female is a greater loss than a dead male.

Thus, it is more worthwhile for the females to invest in a look that will protect them against predators.

Another explanation is that the males are driven by their need to find females to mate with as quickly as possible - and that swimming up to a female whilst wearing a large cap and long antennae requires too much energy, takes too long and entails a risk that other males will get there first.

This also explains why the fashions are more extravagant in the summer than the winter.

“When the water’s cold, it’s more difficult to move through, which makes it extra-hard to swim with accessories,” said Lord.

“This is one of the explanations for why we find water fleas with extreme looks during the summer only, when the water is warm, but not during the rest of the year. Another explanation is that the summer brings more invertebrate predators,” he added. (ANI)

Related Stories

Tags: , , , , , , , , , , , , , , , , , , ,

Posted in Health Science |