Dung Beetle Navigation

Dung Beetle

I think we’re all familiar with the image of the lowly dung beetle, rolling its ball of dung along. Apparently, competition in the wild for the dung is fierce, so the male dung beetles roll it away from the fresh pile as quickly as they can, in a straight line, to keep others from taking it. The male beetle and his mate then bury the dung ball, which will become food for their babies. Fascinating stuff, really!

Scientists already knew that dung beetles used polarized light around the sun during the day to roll a straight line, but the mystery was how they did it at night.

Now they know! Through careful observation and experimentation, they discovered the dung beetles use the bright line marked by our Milky Way galaxy to stay true.

From nationalgeographic.com:

Talk about star power—a new study shows that dung beetles navigate via the Milky Way, the first known species to do so in the animal kingdom.

The tiny insects can orient themselves to the bright stripe of light generated by our galaxy, and move in a line relative to it, according to recent experiments in South Africa.

“This is a complicated navigational feat—it’s quite impressive for an animal that size,” said study co-author Eric Warrant, a biologist at the University of Lund in Sweden.

Read the entire article here.

What Birds Know About Fractal Geometry

Of course, I don’t think birds know a thing about fractal geometry, but here’s an interesting finding about the fractal characteristics of one indicator of a male bird’s health.

It’s the same reason that peacocks have such colorful, ostentatious tails – female birds like them! Evolution at work.

From Science Magazine:

Birds, do your math: The pattern of feathers on the chest of your potential mate might provide a good sense of his or her overall health and well-being. In a new study, researchers find that a single number that describes the complexity of those configurations, a parameter called the fractal dimension, is linked to whether a bird has a strong immune system or is malnourished.

You may read the full article here.

The First Known Solar-Powered Vertebrate

Scientists have discovered the first known solar-powered vertebrate, a salamander. The salamander incorporates algae into its cells and benefits from the oxygen produced by the algae and the algae feed on the salamander’s cells waste products. A symbiotic relation.

From New Scientist:

When you think about it, animals are weird. They ignore the abundant source of energy above their heads – the sun – and choose instead to invest vast amounts of energy in cumbersome equipment for eating and digesting food. Why don’t they do what plants do, and get their energy straight from sunlight?

The short answer is that many do. Corals are animals but have algae living in them that use sunlight to make sugar. Many other animals, from sponges tosea slugs, pull the same trick. One species of hornet can convert sunlight into electricity. There are also suggestions that aphids can harness sunlight, although most biologists are unconvinced.

But all these creatures are only distantly related to us. No backboned animal has been found that can harness the sun – until now. It has long been suspected, and now there is hard evidence: the spotted salamander is solar-powered.

You can read the entire article here.

What If the World’s Soil Runs Out?

Soil erosion is a major problem. It’s estimated that it can take from 100 to 500 years to form an inch of topsoil.

From Time World:

It’s a strange notion, but some experts fear the world, at its current pace of consumption, is running out of useable topsoil. The World Economic Forum, in collaboration with TIME, talked to University of Sydney professor John Crawford on the seismic implications soil erosion and degradation may have in the decades to come.

Is soil really in danger of running out?

A rough calculation of current rates of soil degradation suggests we have about 60 years of topsoil left. Some 40% of soil used for agriculture around the world is classed as either degraded or seriously degraded – the latter means that 70% of the topsoil, the layer allowing plants to grow, is gone. Because of various farming methods that strip the soil of carbon and make it less robust as well as weaker in nutrients, soil is being lost at between 10 and 40 times the rate at which it can be naturally replenished. Even the well-maintained farming land in Europe, which may look idyllic, is being lost at unsustainable rates.

Read the complete article here.

Gorillas grin ‘to reassure friends’

I like that we’re always learning ways in which animals exhibit behavior that was once considered to be exclusively human. It reminds me that we are part of nature; closely related to and intricately linked to our fellow creatures.

From the BBC Nature:

Gorillas bare their teeth in a playful “grin” to reassure one another during play, scientists have discovered.

This “flash of teeth” seems to let their playmate know that they do not intend to harm them.

The researchers, from the University of Portsmouth, study the facial expressions of primates to uncover the evolutionary origins of human smiling and laughter.

They published their findings in the American Journal of Primatology.

Lead researcher Dr Bridget Waller explained that non-human primates have two expressions “that shed light on our smiling”.

Their “playface”, she explained, appears to be a foundation of human laughter.

Read more here.