Tarantulas and Their Kin; How Mosquitoes Find You; Black Holes Aren’t Mysterious at All

There has been a lot of science news this week. It’s like a flood of information bursting explosively through a dam of ignorance. Who built this dam, anyway? How did they get this dam through Parliament? Anyway, among the hundreds of stories we’ve reported this week, here are three interesting vignettes. Two of them involve insects.

Roommates are unlikely

People tend to have one of two reactions to tarantulas: an acute, primal terror that author David Foster Wallace describes as “screaming ghosts,” or the type of attachment more commonly associated with kittens and puppies. People are simply not indifferent to tarantulas.

A study from the University of Turku describes the newly discovered ecological relationships between soft, hairy spiders and amphibians, reptiles and insects. The report mentions the truly astonishing fact that small frogs often coexist with tarantulas, taking advantage of the shelter of the tarantulas’ burrows and doing their hosts a favor by eating insects that may be harmful to the spider or its eggs.

Additionally, the study suggests that tarantulas became hairy as a defense mechanism against predatory ants. The researchers observed army ants entering a tarantula burrow and cleaning up leftover food, leaving the burrow cleaner than they had found it. Some of the ants that attempted to attack the tarantula were repelled by the fringe of stiff, protective hairs on the tarantula’s legs.

“The density of hairs covering the tarantula’s body prevents ants from biting or stinging the spider. We therefore believe that the hairiness may have evolved as a defense mechanism. This hypothesis is supported by the findings that many New World burrowing tarantulas cover their egg sacs with stinging hairs,” says first author Alireza Zamani from the University of Turku.

Quantified chaos

Black holes can only be observed indirectly, through X-ray emissions from accretion disk flares. Many black holes have companion stars and, over time, pull material from their companions into equatorially orbiting rings. These accretion disks are highly dynamic and poorly understood, and astronomers have been trying to model them for decades. Researchers at the University of Helsinki wanted to know precisely how opaque hot areas and transparent cold areas develop within the accretion disk and lead to detectable explosions.

They developed supercomputer simulations to model the interactions between radiation, plasma, and magnetic fields around black holes, including quantum interactions, and determined that the turbulence within the accretion disk is caused by magnetic fields that heat the local plasma and cause it to emit X-rays. This is the first plasma physics model to incorporate quantum interactions between radiation and plasma and answers questions about black hole dynamics that physicists began asking in the 1970s.

The study describes how electrons and positrons, which are antiparticles that annihilate each other, can be found in the same place near the extreme conditions around black holes, and explains how the plasma making up the accretion disk can have hot and cold regions.

“Take the choppah!”

How do mosquitoes manage to target their hosts so precisely? They actually integrate information from multiple sensory sources, including the smell of exhaled CO₂inputs that can vary depending on the distance from their prey. But according to a study by researchers at the University of California, Santa Barbara, one of those senses is infrared vision, similar to the HUD overlay used by the alien hunter in the 1987 film “Predator” to target his human prey. The study found that in combination with CO₂ Detecting infrared radiation from a source with human skin temperature would cause mosquitoes to double their host-seeking behavior.

In the lab, researchers exposed female mosquitoes to human odors and CO₂. In a separate area, they were also exposed to infrared radiation from a source that measured skin temperature. Mosquitoes exposed to IR showed twice as much probing behavior as mosquitoes in the first area.

Nicolas DeBeaubien, a postdoctoral researcher at UCSB, said, “What struck me most about this work was the power of IR. Once we got all the parameters right, the results were undeniably clear.” However, it remains unclear whether rolling in mud to suppress IR is as effective against mosquitoes as it is against exotic predators.

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