Sensor IDs Bugs to Kill
JJ Harrison, Wikimedia Commons
A new sensor could zero in on female mosquitoes -- the only kind that bite -- and spread disease.
Ticks resemble little bumps on skin, but a closer look reveals the barbed mouthpart (hypostome) that's inserted in human flesh and can't easily slip out. Dania Richter of the Technical University of Braunschweig watched, under very high magnification, ticks using other mouthparts to pierce skin, generating “a toehold,” before a breaststroke-like action pulled in the barbed hypostome. The study is published in the latest Proceedings of the Royal Society B.
S. Turner, UC Riverside
This scanning electron micrograph image of a southern house mosquito (foreground) makes evident the straw-like mouthpart used to suck human -- and other -- blood. The red and black additions highlight smelling activity. It’s believed that a mosquito can smell a person from 100 feet away.
Spiders in the genus Loxosceles, including the brown recluse, are among the few common spiders whose bites can seriously hurt people. Greta Binford, an associate professor of biology at Lewis and Clark College, recently studied the spiders, including the one shown here from South America. The spider bites can cause our skin to die. "Our bodies are basically committing tissue suicide," she explained. "That can be very minor to pretty major, like losing a big chunk of skin. The only treatment in that case is usually to have a skin graft done by a plastic surgeon."
Older workers within a rainforest termite species,
, have built-in “explosive backpacks” that become bigger and more deadly over time. The blue in this image -- showing several workers and a soldier termite -- is actually a sack of toxic blue liquid. Jan Šobotnik at Academy of Sciences of the Czech Republic in Prague found that worker termites could explode this toxin onto enemies during suicide missions that help their colonies.
Entomologist Michael Caterina and his team studied clown beetles, which munch on fly larvae found in decomposing bodies He snapped this shot, which shows one such beetle’s mandibles. It’s apparently a bug-eat-bug world, even in the remains of the deceased.
Slimy slugs are the bane of gardeners, but a recently discovered slug species makes others seem tame. The ‘ghost slug,’ found in Cardiff, Wales, lives on land, is carnivorous and possesses blade-like teeth. It’s out all year round -- not just on Halloween.
Sam Droege, Flickr
This fly was photographed after it became stuck in a glob of hand sanitizer, so it was likely frozen in this image seconds before its demise. The photo reveals the fly’s compound eyes, which have the fastest visual responses in the animal kingdom. The tongue-like proboscis is also sticking out.
Leeches are predominantly bloodsuckers that feed on blood from humans and other animals. When leeches bite into a victim, their saliva prevents blood from clotting, causing victims to bleed from the wound for hours. The good news is that this effect has beneficial microsurgery applications, such as helping doctors reattach tiny veins.
David Hughes, Penn State University
The zombie-ant fungus invades an ant’s brain, causing the insect to march to its death at a mass grave near the ant colony. The fungus winds up the winner, since it then erupts via spores that come out of the ant’s head. A parasitic fungus, however -- the white and yellow material in this image -- can castrate the zombie-ant fungus, allowing the ant to live.
Linda Tanner, Flickr
Photographer Linda Tanner spotted this black widow spider in an old, dark barn, heading for a front porch. Black widows are very common, and are often found in garage door slats, hiding in dark corners, under woodpiles and in other places in and around homes. Usually they mind their own business, focusing on their insect prey, but their venom can cause human victims to experience nausea, muscle aches and paralysis of the diaphragm, which can lead to breathing difficulties.
Using lasers, Legos and an algorithm based on a classic spy trick, scientists have created a sensor that can instantaneously classify the insects that fly past it.
The invention offers a powerful and cheap new strategy for quickly identifying infestations that threaten agriculture and human health. Among other applications, the technique could lead to more targeted attacks that would reduce the load of pesticides needed to squelch invasions.
Encouraged by good results in the lab, entomologists are now beginning to test the system in places like Mali, where a massive search has yet to determine exactly where malaria-carrying mosquitoes hide out during the dry season.
"This has the potential to save lives and crops," said Eamonn Keogh, a computer scientist at the University of California, Riverside. "My feeling is that in the next year or two, there will be a lot of applications for this."
Every year, insects kill millions of people by transmitting diseases, and they destroy more than $40 billion of food crops. For nearly 70 years, scientists have been looking for efficient ways to detect infestations as soon as possible to mitigate the damage, but they've repeatedly run up against roadblocks.
Many previous attempts to create automated insect detectors have attempted to use sound to identify insects, but acoustic microphones are limited by distance. The farther away a flying critter is, the less volume a mic will pic up, making the technique useless unless insects fly right in front of the system.
Instead, current methods for surveying insects have remained inefficient and laborious. Scientists often set out sticky-paper traps and then send someone out every week to check and identify what has landed on the paper. Some insects only live for a week or two, so by the time the technician arrives, it may already be too late to beat the infestation. It's also easy for human eyes to make mistakes because so many species look extremely similar to each other.
In search of a better system, Keogh and colleagues turned to a classic James Bond-style spy trick. When a person standing near a glass window speaks, he explained, the glass vibrates. If you want to eavesdrop, you can shine a light on that glass and use the vibrating reflections to interpret what is being said.
Like a spy detector, the new bug-sensing device shines a laser-thin line of light against a board that converts light fluctuations into sounds. These sounds get recorded as MP3 files, which can then be analyzed by a computer program.
A close-up view of a Brown marmorated stink bug -- a common crop pest.Lildobe/Wikimedia Commons
In the recordings, the program can listen for the frequency of wing-beats, which varies from species to species and even between males and females of some species, Keogh said. The team describes the new sensor in a paper currently under review by the Journal of Insect Behavior. Using frequency alone, the program can classify an insect with about 80 percent accuracy.
To make the system even more precise, the algorithm can also be programmed to factor in temperature, humidity and other environmental clues as well as behavioral quirks of various insects, like the time of day they are usually active and the height at which they like to bite.
Biodiversity in the insect world is massive and Keogh's team hopes to build a massive collection of identifiable species by enlisting the help of the public, including elementary schools, where each class could collect data on a single species. The researchers are also working to build the sensors out of Legos, which would make them easy to fix in the field and as cheap as a dollar each.
Potential applications are wide-ranging. In the wild, sensors could track bees to help scientists figure out how colony collapse disorder might be spreading. In orchards, the devices could detect when and where crop-eating insects appear so that farmers could immediately respond with targeted spraying.
In the fight against disease, sensors could be used to identify which of the 3,528 species of mosquitoes just flew through the door of a home so that researchers might know whether the kind that spread malaria are around. Only female mosquitoes bite, so the sensors could also be used to pick out and release only the males form a sterilized population -- a technique that has shown promise in causing population numbers to plunge.
In Mali, entomologist Tovi Lehmann hopes the system will help solve a longstanding mystery. Every year, malaria-carrying mosquitoes disappear during the dry season for up to seven months. But as soon as it rains, they show up instantly. Despite using large human search teams as well as dogs trained to sniff out mosquitoes, scientists still haven't figured out where the mosquitoes go when the rains stop.
If the sensors can be built to stand up to harsh conditions, they could reveal where the mosquitoes hide, possibly allowing for total eradication.
"At this point, we are testing a prototype," said Lehmann, of the Laboratory of Malaria and Vector Research at the National Institute of Allergy and Infectious Diseases in Rockville, Maryland. "The promise is great and I am very enthusiastic about it. They just need a little more work to make them field-ready."