Eavesdropping Moths Predict Bats Next move: Deploy Countermeasures…

In a North Carolina laboratory, a live moth was clamped tight in a box with a microphone and made to panic. Through the panic, its powers of prediction were probed. The moth, a species of tiger moth called Bertholdia trigona, isn’t psychic. Instead, the moths’ hearing is the key. It’s one of two weapons it uses to stymy a deadly predator: the big brown bat. The panicking, if moths can truly be said to panic, may even tell us something more broadly about how, and when, animals respond to the threat of predators. Tiger moths have a peculiar response to the presence of bats, and B.trigona especially. When they hear them approaching, using ears just behind their wings, the moths start making ultrasonic clicks. The clicks—the reason for the microphone in the box— are made by an organ on their sides called a tymbal. For some species of tiger moth, ...(Read More)

Osedax: Ancient bone eaters

  Somewhere, in the depths of the ocean, a marine ambrosia descends from above; the body of a dead whale.  Despite the depth, the corpse won’t be in solitude long; a mini-ecosystem will soon erupt around it, one that could last a decade. The body draws hag fish, sea cucumbers, rat tail fish, brittle star fish, a host of other invertebrates and myriad species of bacteria, all come to feast on the marine bounty. And soon the ‘bone devourers’, Osedax, come too.

Flying Mammals and a New Jumping Gene

Within our DNA are the remains of thousands, maybe millions, of genetic nomads. They once roamed free through the landscape of our genomes; now most are silenced and still, unable to move. These are the ‘jumping genes’, or ‘transposable elements’ to give them their proper name; curious stretches of mobile DNA. Almost 50% of our DNA is made of these remnants. We see them in virtually all organisms, from bacteria, insects and fish all the way through to us humans. In mammals the only active jumping genes we’ve seen are a type called retro-transposons, which scatter copies of themselves throughout genomes. Now a new DNA sequence for a different type of jumping gene, the first active example of its kind ever to be seen in a mammal, has been spotted jumping around in the genome of the brown bat.

Slimy, Weird, Cheaters

Lurking in gutters, gardens and forests, just under-foot, lies something strange. Something almost alien. They lead independent lives as single cells foraging for, and feeding on, bacteria. But when food becomes scarce they work together, in their millions, forming a multicellular ‘organism’ of individuals. In this form they’re more mobile; moving about, looking for food or new environments, displaying something akin to a brainless form of intelligence. They are everywhere, on almost every continent; but they didn’t arrive on a meteorite, like aliens bent on world domination. Instead they’ve been with us for nearly a billion years. They are the ‘slime moulds’. But wherever individuals cooperate for the greater good of their ilk, there are always cheaters; even among the slime moulds.

Food fight: Bacteria’s biological warfare

You’re not just eating for one. You’re eating for trillions. We like to think of ourselves as an individual, but the truth is we are never alone. We are a buzzing hive of bacteria and other microbes that make up our ‘microbiome’. They eke out a living in whatever niches they can find, our skin or parts of our digestive system; we are an ecosystem. Like all ecosystems there is competition for resources, and some microbes don’t take it lying down, they fight. I’ve written before about Cholera’s spring loaded dagger, but microbes have many means at their disposal, some release enzymes to chew off important bits of their competitors, or poison them. But a few go a step further; they use biological warfare: unleashing viruses to kill off the competition.

Fighting fat with… fat?

What do explosives and weight loss have in common?* To find out we need to go back to World War One, to a munitions factory in France. People working with explosives were running high temperatures and losing weight. Some dangerously so. This was no fever, due to some viral or bacterial infection. It was due to a chemical they were using, similar in structure to TNT: dinitrophenol (DNP). Later, in the 1930s, DNP popped up again, this time marketed as a treatment for obesity. It failed due to its high toxicity. We now know how DNP causes these bizarre effects; it short-circuits a key process used by cells to store energy in chemical form, releasing it as heat instead. We’ve since discovered that this is a trick mammals are born to do to. A type of fat, called ‘brown adipose tissue’, or BAT, does the same trick as DNP, only ...(Read More)

A dried up celibate kleptomaniac

If there’s one thing that biologists agree on, it’s that sex is good. Really good*. Huge amounts of time and energy are invested in it. Well, alas, not so much in the act per se, as much as in finding a way to have sex; to tempt a mate or dispatch a rival. But is it really worth the ego busting knock-backs, the frustration, the time and energy? One quirky animal certainly doesn’t think so; it’s had a dry patch on a geological timescale. For the last 80 million years or so a small pond and fresh water dwelling animal called a bdelloid rotifer has done away with sex, and males, entirely. How has it managed for so long without sex? Simple. It steals.

An Unlikely Traveler In The ‘Death Zone’…

It’s called the ‘death zone’. The area above 8,000 meters where humans can no longer acclimatise to the effects of altitude; the oxygen is too low, the air too thin. We can only venture there briefly if we want to survive*. Yet despite the thin air and low oxygen there are reports of an unlikely visitor: geese. The geese in question are bar-headed geese. Normally residents of areas in China and Mongolia that migrate to over-winter in India. Unfortunately, slap-bang in the middle of their migration route lies the home of Everest, the highest mountain range in the world: the Himalaya. How bar-headed geese travel at such altitudes is something of a puzzle for physiologists. Flying for any distance in the death zone is remarkable; it takes 50% more power to fly and with only 40% of the oxygen available (60% reduction in the partial pressure) than at sea level the metabolic costs ...(Read More)