Blogs / Discoblog

Vampirism isn’t just for bats and Edward Cullen anymore. Some ordinary insects are also beginning to covet human blood, sweat, and tears, because these fluids contain valuable salt that is hard to find in their natural environment. Surprisingly, many species are even preferring salt to energy-rich sugar.

The idea that salt attracted bugs first dawned on a team of sweaty scientists studying insects in Peruvian forests. Puzzled by the swarms of tiny bees attacking them, the scientists soon realized that the bees were trying to get a taste of their sweat. Animals need salt to activate nerves and muscles, and to maintain water balance in their cells.

Intrigued, the scientists littered the forest floor with hundreds of vials filled with either sugar or salt and counted the ant species they baited. They found that ant species living within 100 kilometers of the oceans (with easy access to salt) chose sugar over salt. But ant species living farther inland had a noticeable preference for salt. Reporting in the Proceedings of the National Academy of Sciences, the scientists say the salt cravings were only seen in vegetarian ants, since carnivorous ants can get enough salt from the bodies of their prey.

Which brings us to the vampire moths.

(more…)

Many ants are known to be slave masters—their raiding parties steal the young from colonies of rival ants and raise the foreigners as workers in their own nest. However, Susanne Foitzik of Ludwig-Maximilians University in Munich may be the first researcher to study an ant slave rebellion.

The rebels are Temnothorax, tiny ants only about the size of the comma in this sentence. Their captors are called Protomognathus americanus, and despite being only a little larger, these bullies enslave the smaller insects. Inside the larger ants’ nest, which is built inside an acorn, the smaller ants are put to work caring for their masters’ young. But sometimes, Temnothorax slaves revolt against their servile existence and slaughter the Protomognathus larvae they’re supposed to be babysitting, as well as some of the enemy workers.

(more…)

Earlier this month we wrote about a study of adaptable ants that changed their leaf-gathering strategies to bypass a roadblock thrown in their way. These clever insects solve traffic jams much more easily than big-brained humans do, and now scientists want to borrow their secrets to ease our highway woes.

Ants leave a trail of pheromones to show others the best way back to the nest; when others follow, they leave their own pheromones and the trail is reinforced. They all work together through what biologists call “distributed intelligence.” You can see this skill demonstrated in a Slate video here.

(more…)

Leaf-cutter ants are one of the world’s most organized species, sending out swarms of individuals to cut off leaf scraps and carry them back to the nest. Now, it seems, they’re even smarter than we thought: They can adjust on the fly.

To test the insects’ intelligence, a team of scientists led by Audrey Dussutour at the University of Sydney threw a road block in their way. The researchers built a lab setup in which the ants could only travel between a source of leaves and their nest via a short passageway with a roof only one centimeter off the ground. But instead of getting confused or frustrated that their cargo wouldn’t fit under the bridge, the ants adapted their tactics.

(more…)

Who’s the boss? Milkweed is the boss.

Milkweed plants engage in a helpful bit of mutualism with the aphids and ants who take up residence on them. Aphids feed on the milkweed’s sap, then secrete honeydew, which ants eat. The ants, in turn, are the muscle of the operation—they help both the plants and the aphids by fighting off potential predators like caterpillars. The partnership goes three ways, but the power is not equal—milkweed is in control.

(more…)

Residents of five counties in the Houston area have found themselves besieged by a most unwanted visitor: A new species of swarming, electronics-killing ants. Normally found in the Southeast and the Caribbean, these reddish-brown arthropods known locally as “crazy rasberry ants” are thought to have arrived in Houston via a cargo ship a few years ago, and have since spread in droves. Over-the-counter bug sprays can’t touch them, and they’re liable to bite—though not with the painful stinger of that other Texas staple, fire ants, whom the crazy raspberries eat for lunch (literally).

(more…)