Om nom nom…oh, you caught me in the middle of dinner!
While conducting a survey of fish in an area of the Great Barrier Reef, scientists stumbled upon this little tableau: a tasselled wobbegong, or “carpet shark,” in the midst of devouring a brown-banded bamboo shark. (Either that, or they’re just sharing a very intense kiss.) The carpet shark, which hides in the sand and springs out at its prey, has never been photographed eating another shark before, though scientists could tell from poking around in their stomach contents that their distant cousins were sometimes on the menu. Carpet sharks seem to be slow eaters, though: the team hung around for a full 30 minutes to see if it would suck in more of the bamboo shark, but to no avail.
Maybe it just has stage fright.
Images courtesy of Tom Mannering and the journal Coral Reefs
What’s the News: Among the many creepy denizens of Australia—such as the red back spider, seen here hauling a lizard into its nest, and the saltwater crocodile, which kills with its distinctive “death roll”—the assassin bug is right at home. With its erratic, long-legged walk, it stalks along spiders’ webs, caressing its prey with its antennae and then stabbing them with its beak. Now, scientists who spy on these spider-eaters report that the bugs have yet another charming behavior in their toolkit: using the breeze as cover when they go in for the kill.
What’s the News: The loss of large animals is wreaking havoc on Earth’s ecosystems, according to a scientific review published in Science on Friday, causing food chains to fall into disarray, clearing the way for invasive species, and even triggering the transmission of infectious diseases. The decline and disappearance of these large animals, due in large part to human factors such as hunting and habitat loss, has such strong and wide-ranging effects that the review’s authors say it may well be “humankind’s most pervasive influence on nature.”
What’s the News: Most poisonous snakes don’t inject their prey with venom; instead, they bite the prey and venom insidiously trickles down a groove on their fangs into the wound. A new study in Physical Review Letters investigated the physics behind how venom travels down the grooves: It turns out that snake venom has unusual viscosity properties that keep it cohering together until it’s time to flow down the fangs and into the snake’s soon-to-be-snack—the same properties that account for how ketchup seems stuck in the bottle, then flows freely onto your fries.
For most insects, walking onto a spider’s web and disturbing the sticky threads would be a very bad idea. The distinctive vibrations of wriggling prey only serve to draw the spider closer and inevitably ends in the insect getting bitten, wrapped in silk and digested. But this story doesn’t always unfold in the spider’s favour. Some vibrations aren’t made by helpless prey, but by an assassin lurking on the web.
The assassin bug (Stenolemus bituberus) is a spider-hunter. Sometimes, it simply sneaks up to spiders on their own webs before striking, plunging its dagger-like mouthparts into its prey. But it also has a subtler technique. Sitting on the web, it plucks the silken threads with its legs, mimicking the frequency of weakly struggling prey. These deceptive vibes are an irresistible draw to the spider, who rush towards their own demise.
For more devious details, read the rest of this post at Not Exactly Rocket Science.
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Video: Anne Wignall / Macquarie University