This adult male bedbug wants to suck your blood. Photo: Armed Forces Pest Management Board

For thousands of years, humans have shared their beds with blood-sucking parasites. The ancient Greeks complained of bedbugs, as did the Romans. When the lights go off for those suffering from this parasitic infestation today, from under the mattress or behind the bedboard creeps up to 150,000 of the rice grain-sized insects (though average infestations are around 100 insects). While bedbugs are one of the few parasites that live closely with humans yet do not transmit a serious disease, they do cause nasty red rashes in some of their victims, not to mention the psychological terror of knowing that your body becomes a buffet for crawling bloodsuckers after dark. 

By the 1940s this age-old parasite was mostly eradicated from homes and hotels in the developing world. But around 1995, the bedbug tides again turned. Infestations began flaring up with a vengeance. Pest managers and scientists aren’t sure what happened, exactly, but it may have been a combination of people traveling more and thus increasing their chances of encountering bedbugs in run down motels or infested apartments; of bedbugs bolstering their resistance to common pesticides; and of people simply letting their guard down against the now unfamiliar parasites.

Large cities such as New York have particularly suffered from this resurgence. Since 2000, the New York Times has run dozens of articles documenting the ongoing plague of bedbugs, with headlines such as Even Health Dept. Isn’t Safe from Bedbugs and Bringing Your Own Plastic Seat Cover to the Movies.

As many hapless New Yorkers have found, detecting stealthy bedbugs is only the first step of what usually turns into a long, desperate eradication battle.  Most people have to combine both pesticides and non-chemical methods for purging their apartments. In addition to dousing the apartment and its contents in pesticides, this includes throwing away all furniture the bugs are living on (streetside mattresses in NYC with a “BEDBUGS!” warning scrawled across them are not an out-of-the-ordinary sight), physically removing the bodies of poisoned bugs, subjecting the home to extreme heat or cold, or even hiring a bedbug sniffing dog. Sometimes, after so many sleepless nights and days spent meticulously combing the cracks between the mattress and sheets or searching behind couch cushions, residents simply throw up their hands, move out and start their lives over.

Recognizing this ongoing problem, researchers are constantly trying to come up with new methods for quickly and efficiently killing the pests. The latest technique, described today in the Journal of the Royal Society Interface, takes a hint from mother nature and history. For years, people in Eastern Europe’s Balkan region have known that kidney bean leaves trap bedbugs, sort of like a natural fly paper. In the past, those suffering from infestations would scatter the leaves on the floor surrounding their bed, then collect the bedbug-laden greenery in the morning and destroy it. In 1943, a group of researchers studied this phenomenon and attributed it to microscopic plant hairs called trichomes that grow on the leaves’ surface to entangling bed bug legs. They wrote up their findings in “The action of bean leaves against the bedbug,” but World War II distracted from the paper and they wound up receiving little attention for their work.

Rediscovering this forgotten research gem, scientists from the University of California, Irvine, and the University of Kentucky set out to more precisely document how the beans create this natural bedbug trap and, potentially, how it could be used to improve bedbug purging efforts. “We were motivated to identify the essential features of the capture mechanics of bean leaves to guide the design and fabrication of biomimetic surfaces [or synthetic materials that mimic ones found in nature] for bed bug trapping,” they write in their paper.  

Images of bed bug legs (yellow) on bean leaf surfaces with hooked trichomes (green). Scanning electron microscope photo from The Royal Society

They used a scanning electron microscope and video to visualize how the trichomes on the leaves stop the bedbugs in their ravenous tracks. Rather than a Velcro-like entanglement as the 1943 authors had suggested, it seems that the leaves stick into the insects’ feet like giant thorns, physically impaling the pests.

Knowing this, the researchers wondered if they could improve upon the method as a way to treat bedbug infestations, because leaves themselves dry out and can’t be scaled up to larger sizes. “This physical entrapment is a source of inspiration in the development of new and sustainable [or scalable and chemical-free] methods to control the burgeoning numbers of bed bugs,” they write.

They used fresh bean leaves as a template for micro-fabricating produced surfaces that precisely mimicked the leaves. To do this, they created a negative molding of the leaves, then poured in polymers sharing a similar material composition of the living plant’s cell walls.

Fabrication of biomimetic surfaces (d and e) from bean leaves (b and c). (1–3) A negative molding material is poured onto a leaf surface, and pressure is applied. (4–6) The leaf is removed, and the negative mold is filled with the positive replica material. (7) The negative mold is removed leaving the replica. Image from The Royal Society

The team then allowed bedbugs to walk across their synthetic leaves to test their effectiveness compared to the real deal. The fabricated leaves did snag the bugs, but they didn’t hinder the insects’ movements quite as effectively as the living plants. But the researchers are not deterred by these initial results. They plan to continue working on the problem and improving their product by more precisely incorporating the mechanical properties of the living trichomes. The optimistically conclude: 

With bed bug populations skyrocketing throughout the world, and resistance to pesticides widespread, bioinspired microfabrication techniques have the potential to harness the bed bug-entrapping power of natural leaf surfaces using purely physical means.

Researchers used miniature robots to mimic how real ants maneuver networks of their own. Credit: Simon Garnier, et al

For ants, the pheromone-laden foraging trails they leave behind are like lifelines: they direct the workers toward food hubs discovered earlier and help guide them home back to their nest.

These networks of trails can stretch for hundreds of feet, quite the achievement considering many worker ants are less than half an inch in length. One type of harvester ant can lay down a set of trails (PDF) that stretch 82 feet from the entrance of its nest. The trails of a wood ant, an insect measuring just five millimeters (that’s one-fifth of an inch), reach 656 feet, each one branching out into more pathways at up to 10 spots on each trail. The leafcutter ant can build a network that spreads for almost two and a half acres.

Ant species such as these tend to take the shortest path between their colony’s nest and a food source, following branches that stray as little as possible from the direction in which they began their journey. The forks in their network of trails, known as bifurcations, are not symmetrical and don’t branch out into angles of the same size. But do ants use a sophisticated sense of geometry to trace their path, measuring the angles of the roads before picking one?

To learn more, researchers at the New Jersey Institute of Technology (NJIT) and the Research Centre on Animal Cognition in France used miniature robots to replicate the behavior of a colony of Argentine ants on the move, reported today in the journal PLOS Computational Biology. This ant species has extremely poor eyesight and darts around at high speeds, yet it can maneuver through corridor after corridor, from home to food and vice versa.

When no obstacles are around, ants prefer to walk in a straight line without deviating from their course. People are like that too: if we were walking down a street to a restaurant that’s on the same side of the road as we are, we wouldn’t cross to the opposite sidewalk unless something was blocking our way. To imbue this sense of obstacle avoidance into the robots, researchers programmed them to avoid obstacles and follow light trails, which the researchers used as a substitute for pheromone-coated paths.

An “Alice,” a tiny robot measuring two centimeters (just less than one inch), following a trail of light using two photoreceptors. Credit: Simon Garnier, et al

The 10 tiny robots in this study, called Alices, were then tasked to navigate a maze-like environment roughly 60 to 70 times their size, from a starting point representing a nest entrance to an end point signifying a food source. Two photoreceptors, mimicking ant antennae, detected beams of light. As the robots traveled through the maze, researchers introduced a wrench in the little machines’ plans—at random points in their journey, the robots were triggered to turn, a mechanism meant to further mimic ants’ meandering gaits as they creep along their paths. These random turns rotated at angles no greater than 30 degrees, as real ants are not very efficient at physically making U-turns.

In the sped-up video below, the researchers tested the Alices’ navigation skills in a complex network, charging them with choosing the shortest route between their “nest” (on the right) to a “food source (left). Varying beams of light projected onto the maze changed the robots’ movements inside the network as their photoreceptors kicked into action.

The researchers found that, without any knowledge of the geometry of the maze, the robotic ants behaved exactly as real ants do: they made small random turns, but moved in the same general direction. When they reached a fork in the road, this led the robots to choose the path that deviated least from their initial trajectory, even though they weren’t equipped to measure any angles. When they detected a light trail, they turned to follow that path.

The researchers say this means that Argentine ants may not need to use complex cognitive processes to compute the geometry of various trails. But taking the fork in the road that leads to the shortest route to food greatly increases foraging success for an entire colony. So using pheromones with an intuitive spatial knowledge of where food may be, keeps ants on the right track; as more ants follow the path to food, pheromones become more concentrated along the path, further helping to guide ants who have yet to travel. In fact, the navigation method of choosing the correct fork in the road triples the amount of food ants bring back to their nest than if they relied on pheromones alone, says lead author Simon Garnier, a biology professor at NJIT.

“If you have only the pheromones and you don’t have this trick, you’re less efficient because you’re more likely to get the ants trapped into loops,” says Garnier, who runs the institute’s Swarm Lab, which studies insect group behavior. “So they will reinforce their path around the loop, and they’ll just get stuck in this loop and turn and turn forever.”

Such navigation may also help guide ants through underground paths that connect different parts of their nests. Replicating these natural navigation tools allows researchers to better understand the inner-workings of collective animal behavior.

Dead locusts litter Israel’s Negev desert after being sprayed with pesticide on Wednesday. Photo: Rachel Nuwer

Locusts have plagued farmers for millennia. According to the Book of Exodus, around 1400 B.C. the Egyptians experienced an exceptionally unfortunate encounter with these ravenous pests when they struck as the eighth Biblical plague. As Exodus describes, “They covered the face of the whole land, so that the land was darkened, and they ate all the plants in the land and all the fruit of the trees that the hail had left. Not a green thing remained, neither tree nor plant of the field, through all the land of Egypt.”

Locusts attacks still occur today, as farmers in Sudan and Egypt well know. Now, farmers in Israel can also join this unfortunate group. Earlier today, a swarm of locusts arrived in Israel from Egypt, just in time for the Jewish Passover holiday which commemorates Jews’ escape from Egyptian slavery following the ten Biblical plagues. “The correlation with the Bible is interesting in terms of timing, since the eighth plague happened sometime before the Exodus,” said Hendrik Bruins, a researcher in the Department of Man in the Desert at Ben-Gurion University of the Negev in Israel. “Now we need to wait for the plague of darkness,” he joked.

With the help of the Lord, Moses delivers a plague of locusts upon the Egyptians, seen in the photo of a Bible page above. Photo via New York Public Library, Renaissance and medieval manuscripts collection

While the timing is uncanny, researchers point out that–at least in this case–locust plagues are a normal ecological phenomenon rather than a form of divine punishment. “Hate to break it to you, but I don’t think there’s any religious significance at all to insects in the desert, even a lot of them, and even if it seems reminiscent of a certain Biblically described incident,” said Jeremy Benstein, deputy director of the Heschel Center for Sustainability in Tel Aviv.

In this region of the world, locusts swarm every 10 to 15 years. No one knows why they stick to that particular cycle, and predicting the phenomena remains challenging for researchers. In this case, an unusually rainy winter led to excessive vegetation, supporting a boom in locust populations along the Egyptian-Sudanese border. As in past swarms, once the insect population devours all of the local vegetation, the hungry herbivores take flight in search of new feeding grounds. Locusts–which is just a term for the 10 to 15 species of grasshoppers that swarm–can travel over 90 miles in a single day, carried by the wind. In the plagues of 1987 and 1988 (PDF)–a notoriously bad period for locusts–some of the befuddled insects even managed to wash up on Caribbean shores after an epic flight from West Africa.

When grasshoppers switch from a sedentary, solo lifestyle to a swarming lifestyle, they undergo a series of physical, behavioral and neurological changes. According to Amir Ayali, chair of the Department of Zoology at Tel Aviv University, this shift is one of the most extreme cases of behavioral plasticity found in nature. Before swarming, locusts morph from their normal tan or green coloring to a bright black, yellow or red exoskeleton. Females begin laying eggs in unison  which then hatch in synch and fuel the swarm. In this way, a collection of 1 million insects can increase by orders of magnitude to 1 billion in a matter of months.

From there, they take flight, though the exact trigger remains unknown. Labs in Israel and beyond are working on understanding the mathematics of locust swarming and the neurological shifts behind the behaviors that make swarming possible. ”If we could identify some key factors that are responsible for this change, we could maybe find an antidote or something that could prevent the factors that transform innocent grasshoppers from Mr. Hyde to Dr. Jekyll,” Ayali said. “We’re revealing the secrets one by one, but there’s still so much more to find out.”

A swarm of locusts will consume any green vegetation in its path–even toxic plants–and can decimate a farmer’s field almost as soon as it descends. In one day, the mass of insects can munch its way through the equivalent amount of food as 15 million people consume in the same time period, with billions of insects covering an area up to the size of Cairo, Africa’s largest city. As such, at their worst locust swarms can impact some 20 percent of the planet’s human population through both direct and indirect damages they cause. In North Africa, the last so-called mega-swarm invaded in 2004, while this current swarm consists of a measly 30 to 120 million insects. 

Estimating the costs exacted by locusts swarms remains a challenge. While locust swarms reportedly cause more monetary damage than any other pest, it’s hard to put an exact figure on the problem. Totaling the true crost depends on the size of the swarm and where the winds carry it. To be as accurate as possible, costs of pesticides, food provided to local populations in lieu of wrecked crops, monitoring costs and other indirect effects must be taken into account. No one has yet estimated the cost of this current swarm, though the United Nation’s Food and Agriculture Organization (FAO) allots $10 million per year solely to maintain and expand current monitoring operations.

Locusts covering a bush during the 2004 swarm near the Red Sea cost in Israel. Photo: Amir Ayali

This morning, the Israeli Ministry of Agriculture sprayed pesticides on an area of around 1,000 hectares near the Egyptian border. To quell a plague of locusts, pest managers have to hit the insects while they’re still settled on the ground for the night and before they take flight at dawn. So far, pesticide spraying is the only option for defeating the bugs, but this exacts environmental tolls. Other invertebrates, some of them beneficial, will also shrivel under the pesticide’s deadly effects, and there’s a chance that birds and other insectivores may eat the poisoned insect corpses and become ill themselves. Researchers are working on ways to develop fungus or viruses that specifically attack locusts, but many of those efforts are still in initial investigative stages. However, the company Green Muscle developed a commercially available fungus that affects only locusts.

Even better, however, would be a way to stop a swarm from taking flight from the very beginning. But this requires constant monitoring of locust-prone areas in remote corners of the desert, which is not always possible. And since the insects typically originate from Egypt or Sudan, politics sometimes get in the way of quashing the swarm before it takes flight. “We really want to find them before they swarm, as wingless nymphs on the ground,” Ayali said. “Once you miss that window, your chances of combating them are poor and you’re obliged to spray around like crazy and hope you catch them on the ground.”

In this case, Egypt and Israel reportedly did not manage to coordinate locust-fighting efforts to the best of their abilities. “If you ask me, this is a trans-boundary story,” said Alon Tal, a professor of public policy at Ben-Gurion University. “This is not a significant enemy–with an arial approach you can nip locusts in the bud–but the Egyptian government didn’t take advantage of the fact that they have quite a sophisticated air force and scientific community just to the north.”

Ayali agrees that the situation could have been handled better. He also sees locusts as a chance to foster regional collaboration. Birders and ornithologists from Israel, Jordan and Palestine often cooperate in monitoring migratory avian species, for example, so theoretically locusts could likewise foster efforts. “Maybe scientists should work to bridge the gaps in the region,” Ayali said. “We could take the chance of this little locust plague and together make sure we’re better prepared for the next.”

For now, the Israelis have smote the swarm, but Keith Cressman, a senior locust forecasting office at the FAO’s office in Rome warns that there is still a moderate risk that a few more small populations of young adults may be hiding out in the desert. This means new swarms could potentially form later this week in northeast Egypt and Israel’s Negev region. His organization warned Israel, Egypt and Jordan this morning of the threat, and Jordan mobilized its own locust team, just in case.

For those who do come across the insects (but only the non-pesticide covered ones!), Israeli chefs suggest trying them out for taste. Locusts, it turns out, are the only insects that are kosher to eat. According to the news organization Haaretz, they taste like “tiny chicken wings,” though they make an equally mean stew. “You could actually run out very early before they started spraying and collect your breakfast,” Ayali said. “I’m told they’re very tasty fried in a skillet, but I’ve never tried them myself.”

A swarm of locusts descends upon Israel. Photo by Amir Ayali

Sign up for our free newsletter to receive the best stories from Smithsonian.com each week.

Wild bees, such as this Andrena bee visiting highbush blueberry flowers, provide crucial pollination services to crops across the globe. Photo by Daniel Cariveau

Insect pollination is crucial for the healthy development of our favorite foods, from apples and avocados to cucumbers and onions. Of the 100 crop species that provide 90 percent of the global population’s food, nearly three-quarters rely on pollination by bees. The rest need beetles, flies, butterflies, birds and bats to act as pollinators. It’s a mutually beneficial system—the flowers of most crops require pollen from another plant of the same crop to produce seeds or fruits, and bees and other critters transfer pollen from one plant to the next as they drink a flower’s nectar.

The agriculture industry relies on both wild pollinators and human-managed ones like honeybees, kept and cared for in hives across the country. Concern over the latter’s gradual decline has grown in recent times, but new research shows it might be the wild pollinators we should be worrying about.

In a study of 600 fields of 41 major crops (fruits, grains and nuts) on six continents, published today in the journal Science, researchers found that wild insects pollinate these crops more effectively than honeybees that are in the care of humans. In fact, compared to bees living in apiaries, wild pollinators lead to twice as much of what’s called “fruit set”—the amount of flowers that develop into mature fruits or seeds.

Pollination is essential for the production of fruits like cherries, cranberries and blueberries. Blueberries, along with tomatoes, especially depend on buzz pollination, a process by which bees vibrate their flight muscles rapidly to unleash a visible cloud of pollen into a flower. Honeybees aren’t capable of this kind of pollination, says lead study author Lucas Garibaldi, a professor at the National University of Río Negro in Argentina. Of all pollinator-dependent crops, approximately 8 percent require buzz pollination, he says.

Pollination, then, is central to ensuring our both our food staples and our varied diet.“These ecosystem services are free, but they’re important for our survival,” Garibaldi adds. “They need to be promoted and maintained if we want to continue living on this planet.”

Another new study found that wild bee population, as well as the number of different species of the insects, has plummeted over the last 120 years. Researchers used observations of interactions between plants and their pollinators in Illinois collected at three points in time: in the late 1800s, the 1970s and the first decade of this century. Of the 109 bee species seen visiting 26 woodland plants in the 19th century, only 54 remained by 2010. Rising temperatures caused mismatches in peak bee activity, measured by visits to different plants, and flowering times, a break in the delicate balance of insect-plant relationship.

Less diversity in the wild bee population meant fewer interactions between flowers, a change that in the agricultural world could result in smaller crop yields, says lead author Laura Burkle, an ecology professor at Montana State University. This throws off global agriculture production and speeds up land conversion to compensate for the loss.

“Things have changed for the worst,” Burkle says. “There’s an incredible amount of robustness within these interaction networks of species that allow them to persist in the face of really strong environmental changes, both in temperature and land-use change.” Unfortunately, these pollinators are “getting punched from a variety of sides,” she adds.

Can honeybees substitute for our disappearing wild pollinators? Garibaldi and colleagues found that these insects couldn’t fully replace the contributions of diverse populations of pollinators for a wide range of crops on farmlands on every continent. Flooding farmland with human-managed honeybees only supplemented pollination by wild insects, even for crops such as almonds, whose orchards are stocked routinely with bees.

Human-managed hives stocked with bees, ready to aid in pollination at an almond grove. Photo by Daniel Cariveau

Several culprits are behind the continuing decline of these wild pollinators. The insects usually live in forests and grasslands, and continuing conversion of such natural habitats into farmland results in shrinking numbers and types of wild pollinators, meaning fewer flowers receive the pollen necessary for reproduction. 

Last year, many plants in the eastern U.S. flowered a month earlier than any other time in the last 161 years, a result of such unusually warm weather. Burkle says bee development doesn’t always catch up to changing flowering times in plants, which leads to more mismatches in interaction and decreased pollination services. Another study in the same year found that elevated levels of carbon dioxide, combined with the use of nitrogen-infused fertilizer, altered some plants’ lifetime development. The toxic pairing led them to produce flowers with nectar more attractive to bumblebees than usual, but caused the plants to die sooner.

The waning insect population has already taken a measurable toll on crop production, including on one very near and dear to our hearts: coffee. A 2004 study of coffee pollination in Costa Rica found that when numbers of human-introduced honeybees shrunk in a given forest area, diverse pollinators native to the area, such as stingless bees known as meliponines native to the area, helped compensate for the loss. But these insects couldn’t survive at the edges of the forest like honeybees could, so the production of coffee, a crop highly dependent on pollination, eventually plummeted.

“This study supports the theoretical prediction that having many different species, which each respond to the environment in slightly different ways, is like having a stock portfolio from many different companies, rather than investing all your money in a single company’s stock,” explains Jason Tylianakis, a terrestrial ecology professor at the University of Canterbury in New Zealand. Tylianakis discussed the implications of Science’s two new studies in a paper also published today. “We should expect this kind of ‘insurance effect’ to become less common as more native pollinators go extinct.”

Given the mounting evidence, Tylianakis writes in an email that concerns about a global pollination crisis are not overstated. A changing climate, the rapid spread of farmland and a reliance on pesticides means diverse, wild pollinators will continue to face challenges as this century unfolds. If pollinators are dying out worldwide—and if pace of this die out continues with the variety of species getting cut in half each century, leaving behind less effective substitutes—food production as we know it could start to crumble.

“The bottom line is that we need biodiversity for our survival, and we can’t simply replace the services provided by nature with a few hand-picked species like the honeybee,” he says.

A male human head louse. Photo by Flickr user Gilles San Martin

Parasites have been around for more than 270 million years. Around 25 million years ago, lice joined the blood-sucking party and invaded the hair of ancient primates. When the first members of Homo arrived on the scene around 2.5 million years ago, lice took advantage of the new great ape on the block for better satisfying its digestive needs. As a new genetic analysis published today in PLoS One shows, mining these parasites’ genomes can lend clues for understanding the migration patterns of these early humans.

The human louse, Pediculus humanus, is a single species yet members fall into two distinct camps: head and clothing lice–the invention of clothing likely put this divide into motion. Hundreds of millions of head lice infestations occur each year around the world, most of them plaguing school-aged children. Each year in the United States alone, lice invade the braids and ponytails of an esimtated 6 to 12 million kids between the ages of 3 to 11. Clothing lice, on the other hand, usually infect the homeless or people confined to refugee camps. Clothing lice–also referred to as body lice–are less prevalent but potentially more serious because they can serve as vectors for diseases such as typhus, trench fever and relapsing fever.

Researchers have studied the genetic diversity of head and clothing lice in the past, but scientists from the Florida Museum of Natural History at the University of Florida decided to tap even deeper into the parasites’ genome, identifing new sequences of DNA that could be used as targets for tracking lice evolution through time and space. From these efforts, they found 15 new molecular markers, called microsatellite loci, which could help uncover the genetic structure and breeding history behind different lice populations–and potentially their corresponding humans of choice.

Using those genetic signals, they analyzed the genotypes of 93 human lice taken for 11 different sites around the globe, including North America, Cambodia, Norway, Honduras, the UK and Nepal, among others. They collected lice from homeless shelters, orphanages and lice eradication facilities.

Inbreeding, it turned out, is common in human lice around the world. Lice in New York City shared the most genetic similarities, pointing to the highest levels on inbreeding from the study samples. Clothing lice tended to have more diversity than head lice, perhaps due to an inadvertent bottlenecking of the head lice population due to high levels of insecticides those parasites are regularly exposed to. As a result of repeated run-ins with anti-lice shampoos and sprays, only the heartiest pests would survive, restraining the overall diversity of the population. Insecticide resistance is a common problem in head lice, but less of an issue with clothing lice. The authors identified one possible gene that may be responsible for much of the head louse’s drug resistance, though further studies will be needed to confirm that hunch. 

The researchers also analyzed lice diversity to see how it relates to human migration. They found four distinct genetic clusters of lice: in clothing lice from Canada, in head lice from North America and Europe, in head lice from Honduras and in all Asian lice.

Here’s the authors present a map of lice genetic diversity. The colored circles indicate sampling sites, with the different colors referring to the major genetic clusters the researchers identified. The grey flowing arrows indicate proposed migrations of modern humans throughout history, and the colored arrows represent the hypothetical co-migration of humans and lice.

Photo from Ascunce et al., PLoS One

How this geographic structure reflects human migration, they write, will require more sampling. For now, they can only speculate about the implications:

Although preliminary, our study suggests that the Central America-Asian cluster is mirroring the (human host) colonization of the New World if Central American lice were of Native American origin and Asia was the source population for the first people of the Americas as has been suggested. The USA head louse population might be of European decent, explaining its clustering with lice from Europe. Within the New World, the major difference between USA and Honduras may reflect the history of the two major human settlements of the New World: the first peopling of America and the European colonization after Columbus.

Eventually, genetic markers in lice could help us understand interactions between archaic hominids and our modern human ancestors, perhaps answering questions such as whether or not Homo sapiens met with ancient relatives in Asia or Africa besides Homo neanderthalensis. Several kinds of louse haplotypes, or groups of DNA sequences that are transmitted together, exist. The first type originated in Africa, where its genetic signature is strongest. A second type turns up in the New World, Europe and Australia, but not in Africa, suggesting that it may have evolved first in a different Homo species whose base was in Eurasia rather than Africa. If true, then genetic analysis may give us a time period for when humans and other Homo groups for came into contact. And if they interacted close enough to exchange lice, perhaps they even mated, the researchers speculate.

So not only can the genetic structure of parasite populations help us predict how infections spread and where humans migrated, it may give insight into the sex-lives of our most ancient ancestors.

Footage from Brazil’s “spider rain.” Photo: TV45000

The Northeast may be prone to blizzards this time of year, but in Brazil it’s raining spiders. In a video that’s covered the Internet like an immense web, a local photographer captures images of thousands of spiders shimmying up and down silk threads attached to telephone pole wires. The footage gives the distinct impression of a shower–or perhaps light snow–of spiders sprinkling down on the shocked residents below.

Erick Reis, a 20-year-old web designer in Santo Antonio da Platina, a town about 250 miles west of Sao Paulo, captured the striking video that has since accumulated more than 2 million YouTube views over the course of the week.  “I was shooting an engagement party for some friends of mine and I saw the spiders when I was leaving, now in the late afternoon,” he explained to TV450000, which posted the video. “I’ve never seen anything like it before.”

According to biologist Marta Fischer of the Pontifical Catholic University of Parana, however, the phenomenon is not so strange. ”This type of spider is known to be quite social,” she said. “They are usually in trees during the day and in the late afternoon and early evening construct sort of giant sheets of webs, in order to trap insects.”

Scientists have described around 40,000 species of spiders around the world, but only a handful of them are social. These 23 species are scattered around the world and sometimes swarm, like ants or bees. Females often outnumber males 10 to 1 in colonies that can exceed 50,000 individuals.

Around Sao Paulo and its neighboring cities, she said, it’s not an unusual site to see a sky speckled by spiders. The species, Anelosimus eximius, can be found from Panama to Argentina and lives in colonies sometimes comprised of thousands of individuals. Each spider is around the size of a pencil eraser. As Examiner reports, the species’ webs can stretch from the ground up to tree canopies or human constructions 65 feet high.

If strong winds come along, the web may detach from its anchors, carrying the spiders and their ruined home to new sites where they appear to “rain down.” Catching rides on the wind–en mass–was likely what happened in Santo Antonio da Platina. While the humans gawked below, the flustered spiders were simply trying to pull themselves together after an unexpected journey from some forest or park.

Before North American readers breathe a sigh of relief that this isn’t happening a bit closer to home, however, it’s worth noting that similar colonies live in Texas. In Lake Tawakoni State Park, just east of Dallas, Guatemalan long-jawed spiders construct enormous webs covering up to 600 foot stretches. The spiders build the huge webs in less than two weeks. Researchers think the spiders achieve such sudden engineering feats thanks to their “remarkable reproductive capabilities and ability to disperse by ballooning,” according to A Field Guide of Scorpions and Spiders of Texas.

So far, Dallas residents haven’t reported massive sheets of webs and their arachnid residents “ballooning” into backyards. But, as witnessed by residents of Santo Antonio da Platina,  stranger things have happened. 

A cockroach diligently cleans his antenna. Photo by Ayako Wada-Katsumata

When encountering a two-inch American cockroach, most people quickly skedaddle the other way or raise a foot to stomp the little creeper out of existence. For those curious few who stick around to quietly observe the roach, however, the insect will inevitably fall into a certain diligent, repetitive motion. First, it reaches its spiny little roach feet up towards its head, then grips the base of one of its antennae and finally, as if it were spinning yarn at triple speed, threads the length of its antennae through its furiously working mouthparts.

Insects such as cockroaches, house flies and carpenter ants often engage in such antennae-grooming behavior. Like many animals, scientists know that insects frequently clean themselves, but few researchers have investigated just why bugs bother. Antennae serve not only to feel out the environment but also to sense odors, so researchers have long suspected that grooming keeps the antennae in top shape. But what, specifically, are they scrubbing from their bodies? Do roaches self-clean to remove bacteria or bits of gunk from their last meal?

To figure out just why roaches groom, lead author Katalin Böröczky and colleagues from North Carolina State University along with researchers from the Russian Academy of Sciences observed antennae-cleaning behaviors in a couple dozen adult male American cockroaches, describing their experiment today in Proceedings of the National Academy of Sciences. The researchers used an array of methods to restrain the roaches from self-grooming so that they could compare groomed and ungroomed antennae. In some cases, the scientists used a small plastic clip to tether one antenna at the base of the roaches’ heads. The frustrated insects repeatedly attempted to grab hold of their lassoed antenna but could not get a grip on it in order to clean it. Some roaches also had their mouthparts glued together while others were kept in a box too small to allow for self-grooming.

Here, you can see one of the roaches stymied by the plastic antennae blockers:

Over a period of 24 hours, the tethered antenna began to appear shinier than the other non-tethered one. Examining the shiny antenna with a scanning electron microscope revealed an unidentified substance blocking the roaches’ sensory pores and coating their antennae. The unclean antennae built up three to four times more of the stuff than the clean ones over the day.

To figure out what the unknown build-up was, the researchers took samples of it and analyzed it with gas chromatography, a technique that separates different components of a chemical compound. They found that the natural secretions that the cockroach gives off accounted for most of the substance–mostly fatty molecules that help regulate water loss in insects. Despite the seemingly sterile environment, other external contaminants were stuck on the antennae as well, including stearic acid from surfaces in the roaches’ container and geranyl acetate from the air.

The researchers guessed that this build up might impair the roaches’ ability to sniff out olfactory signals with their antennae. To test this hypothesis, they exposed roaches with groomed and ungroomed antennae to sex pheromones and other odors. Just as they suspected, roaches with clean antennae were more receptive to the odors around them than those with unclean ones. “We conclude that the disruption of grooming interferes with general olfaction,” the authors write in their paper.

Finally, to see if these findings extended to other insects, the researchers repeated their experiment in flies, ants and German cockroaches, all of which exhibited the same build up and loss of antennae function when prevented from self-grooming. They conclude that “our observations with four phylogenetically diverse species indicate that this hitherto unknown role for grooming is common to a wide diversity of insects.”

Just as humans scrub off to remove dead skin cells, sweat and dirt from the day, insects busy themselves to keep clean. While we may share this commonality with earth’s most abundant group of species, however, it may not be quite enough to inspire empathy for the next cockroach that finds its way into a closet or kitchen drawer.

A new study shows the tiny insects orient themselves by the stars. Image via Current Biology, Dacke et. al.

Science has shown us that a number of organisms use the stars for navigation: songbirds, harbor seals and, of course, humans. But a new study by a team of Swedish and South African researchers published today in the journal Current Biology indicates that a rather unexpected creature can be added to this list—the lowly dung beetle.

The beetles are known for creating small balls made of animal feces (i.e. dung) and rolling them in straight lines over long distances. They do this because the dung is their main food source—and other beetles often try to steal the dung once it’s been rolled into a ball. The surest way of retaining the valuable dung once it’s been packed into a ball is to move it away from the original dung pile as quickly as possible:

Researchers, though, have long been mystified by the tiny beetles’ ability to roll the dung balls in straight lines at night. “Even on clear, moonless nights, many dung beetles still manage to orientate along straight paths,” said lead author Marie Dacke of Lund University in Sweden. “This led us to suspect that the beetles exploit the starry sky for orientation—a feat that had, to our knowledge, never before been demonstrated in an insect.”

To test the hypothesis, the scientists set up a circular ring with a radius of about 4 feet outside and placed a dung pile at the center. They tested how long it took the beetles to reach the ring from the center—a measure of how straight their paths were—and found that their navigational abilities were relatively similar with either a full moon in the sky or at least a clear view of the stars. When they placed tiny blinders on the beetles’ eyes or subjected them to overcast conditions, though, their paths became much more windy.

Next, they placed a number of beetles in a planetarium and performed a similar test. Their paths were straightest with all the stars turned on, but were almost as true with just the Milky Way—indicating that they are particularly dependent on the Milky Way’s streak of light for navigation.

Image via Current Biology, Dacke et. al.

When the researchers turned on a large number of dim stars—many of which lie in the band of the Milky Way—the beetles’ navigation speed still remained similar. It was only when they left on just 18 of the brightest stars that their pathways became significantly windier.

The authors say that this proves that the beetles don’t rely on one particular star or celestial object for navigation, but rather take in the totality of the Milky Way—which appears as a startlingly bright band of light in many rural areas—to orient themselves on the ground.

It might seem disgusting, but a new study indicates that insects like mealworms might be the climate-friendly protein alternative of the future. Image via Wikimedia Commons/Pengo

The year is 2051. Given the realities of climate change and regulations on carbon emissions, beef and pork–protiens with high carbon footprints–have become too expensive for all but the most special of occasions. Luckily, scientists have developed an environmentally-friendly meat solution. Sitting down for dinner, you grab your fork and look down at a delicious plate of….mealworms.

That, anyway, is one possibility for sustainable meat examined by Dennis Oonincx and Imke de Boer, a pair of scientists from the University of Wageningen in the Netherlands, in a study published today in the online journal PLOS ONE.

In their analysis, cultivating beetle larvae (also known as mealworms) for food allowed the production of much more sustainable protein, using less land and less energy per unit of protein than conventional meats, such as pork or beef. In a 2010 study, they found that five different insect species were also much more climate-friendly than conventional meats—a pound of mealworm protein, in particular, had a greenhouse gas footprint 1% as large as a pound of beef.

“Since the population of our planet keeps growing, and the amount of land on this earth is limited, a more efficient, and more sustainable system of food production is needed,” Oonincx said in a statement. “Now, for the first time it has been shown that mealworms, and possibly other edible insects, can aid in achieving such a system.”

This prospect might seem absurd—and, for some, revolting—but the problem of greenhouse gas emissions resulting from meat production is quite serious. The UN estimates that livestock production accounts for roughly 18% of all emissions worldwide, caused by everything from the fuel burned to grow and truck animal feed to the methane emitted by ruminants such as cows as they digest grass. Of most concern, since world populations are increasing and growing more wealthy, is that the demand for animal protein is expected to grow by 70-80% by 2050.

Pound for pound, mealworm protein (green) produces much lower amounts of greenhouse gas emissions than both the high (red) and low (blue) estimates for conventional protein sources. Image via Oonincx

Insects like mealworms, the researchers suggest, can help to solve this problem. Since they aren’t warm-blooded (like mammals) they expend far less energy per pound as part of their metabolism, so they needn’t eat as much to survive. As a result, less energy goes into cultivating them as a food source, and less carbon dioxide gets emitted into the atmosphere.

The researchers came to this conclusion by conducting an environmental impact assessment for a commercial mealworm producer in the Netherlands (mealworms are often cultivated as a food for reptile and amphibian pets). They analyzed every input used in the process of rearing the worms, including the energy used to heat the incubators, the grain used as feed and the cardboard used for rearing cartons. Even including all these inputs, the worms were much more climate-friendly than conventional protein sources.

In Thailand and other Asian countries, insects have long been considered a viable food source. Image via Flickr user Chrissy Olson

Sure, you might be pretty reluctant to sit down to a bowl of mealworm macaroni, but in a number of places around the world—especially in Asia—they’re considered a perfectly normal food. Even some people here in the U.S. agree: A quick search reveals mealworm recipes you can cook up at home, like mealworm french fries and stir-fried mealworms with egg, while Mosto, a trendy restaurant in San Francisco, serves crispy mealworms over ice cream.

Better yet, mealworms are more healthy than conventional meats, too. According to PBS, a pound of mealworms has more protein and half as much fat as a pound of pork.

Still, there is one inescapable obstacle to widespread mealworm consumption: the “yuck” factor. For those of us who don’t typically eat insects, a forkful of mealworms triggers a profound feeling of disgust. Even this blogger—fully convinced of the wisdom of eating insects—can acknowledge from personal experience (an encounter with a bag of fried mealworms in Thailand) that knowing the worms are okay to eat and actually eating them are entirely separate matters.

Illacme plenipes, the record-breaking millipede, only lives in a few woodlands in Northern California. Image via Marek et. al.

Yesterday, the first full description of the species was published in the joural ZooKeys. The study was led by Paul Marek of the University of Arizona. The millipede is known only from 17 live specimens Marek’s team found in a home range that is remarkably specific: three small wooded areas strewn with Arkose sandstone boulders in the foothills of San Benito County, California, near San Francisco.

The rareness of the millipede meant that from 1928 until 2005—when Marek, then a Ph.D. student, found a few specimens in the woods near San Juan Bautista—most scientists had simply assumed the species had gone extinct. Over the past seven years, Marek and his colleagues have taken several trips to the area, typically searching for hours before finding a single specimen clinging to the side of a boulder or tunneling four to six inches down into the ground.

In studying these specimens under a microscope, Marek has discovered a number of surprising characteristics that go beyond its legs. ”It basically looks like a thread,” Marek told LiveScience. “It has an uninteresting outward appearance, but when we looked at it with SEM [scanning electron microscopes] and compound microscopes, we found a huge, amazingly complex anatomy.”

The new analysis revealed that the millipede has no eyes, disproportionately long antennae and a rudimentary fused mouth adapted for sucking and piercing plant structures. It also has specialized body hairs on its back that produce silk, which may be used as a defense mechanism to clear bacteria off the millipedes’ bodies.

A microscope image of the species’ specialized body hairs that produce a silk secretion. Image via Marek et. al.

Of course, the legs are the most striking part of the species’ anatomy. Despite the name millipede, no species are known to have 1,000 legs, but Illacme plenipes comes closest (its Latin name actually means “in highest fulfillment of feet”). The male specimens examined had at most 562 legs, but the females had more, with the winner at 750.

Most millipedes have somewhere between 80 and 100 legs. Marek and his colleagues speculate that this species’ extreme legginess could be a beneficial adaptation for subterranean tunneling or even for clinging to the boulders widely found in the species’ habitat.

Most millipedes have 80 to 100 legs, but this species has up to 750. Image via Marek et. al.

DNA analysis has revealed that its closest cousin, Nematozonium filum, lives in Africa, with the two species’ ancestors apparently splitting apart sometime soon after the breakup of Pangea, more than 200 million years ago.

The team has tried to grow the millipedes in a lab but has so far been unable to. They caution that the species could be extremely endangered—in 2007, they stopped searching for wild specimens out of fears that they were depleting the population—and advocate for a formal protection listing, so scientists will have the time to learn more about them before the millipedes go extinct.

The giant swallowtail, a Southern butterfly, has historically not been found in Massachusetts, but in recent years it has appeared more and more frequently. Photo via Harvard University/Frank S. Model

Over the past few decades, researchers have found evidence that the global climate is changing in an increasingly wide range of places: the retreat of Arctic sea ice, the gradual acidification of the oceans and the overall warming of the atmosphere. A new study by researchers draws upon a more unlikely source—19 years of records of an amateur naturalist group called the Massachusetts Butterfly Club.

It all started when Harvard biologist Greg Breed and his colleagues, who conduct research in the 3000-acre tract of land known as the Harvard Forest, wanted to look into the movements of migratory animal populations over time as a proxy for regional climate shifts. If warmer-climate species were slowly moving into the area, it could indicate a steady warming of the climate over time. They found, however, that no researchers had collected thorough data on any migratory animal species in the region.

Then they discovered that the amateur members of the Butterfly Club had kept meticulous records of the species they saw for nearly two decades, carefully charting each butterfly they encountered on nearly 20,000 butterfly-observing expeditions across the state. Breed and the others realized they could analyze this rich data set in order to develop an understanding of climatic changes over time.

Their results, published on Sunday in the journal Nature Climate Change, are heartening in that they put to good use the careful work of citizen scientists—and depressing in that they provide further support for the fact that the climate is changing and disrupting wildlife populations. “Over the past 19 years, a warming climate has been reshaping Massachusetts butterfly communities,” Breed said in a Harvard press release.

Specifically, the research team found that a number of temperate or even subtropical butterfly species that historically had ranges that ended south of Massachusetts have been showing up in ever-greater numbers in recent years. The zebulon skipper, for instance, was virtually unknown in Massachusetts in the 1980s. Over the past two decades, though, the butterfly club members spotted them more and more often—and they were 18 times more likely to spot a zebulon skipper in 2011 than in 1992, the first year of the records.

Conversely, species that originally had ranges that started roughly in Massachusetts and extended mostly to the North were much less likely to be found as of 2011. More than 75 percent of the species that had a range with a center north of Boston had decreasing populations over the course of the study. Presumably, these species moved north to stay within the range of their preferred climate. On the other hand, southerly species were disproportionately more likely to increase in population in Massachusetts over time, as they followed their preferred climate into the state.

The atlantis fritillary, a species with a range than extends north of Massachusetts, has declined in population by more than 80 percent in the state over the past two decades but still receives no formal protection. Photo via Harvard University/Frank S. Model

The researchers say this raises issues with current methods of butterfly species protection—and, for that matter, protection for all forms of wildlife that easily migrate between different locales. Many of the species that had experienced a rapid increase in population were still under formal protection, such as the frosted elfin, which had become 10 times more frequent over the course of the study. On the other hand, many northerly species had declined dramatically but still haven’t been listed as threatened and don’t receive formal protection measures. The researchers advocate more responsive updating of threatened and endangered species lists based on the latest data.

Of course, a more accurate rendering of which species are at risk won’t help much if our approach to conserving them is outdated, too. Traditionally, butterfly conservation methods focus on habitat protection as a key strategy, but this type of work demonstrates that in our new, quickly changing climate, local habitat might be less important than shifting boundaries between previously stable climate zones. “For most butterfly species, climate change seems to be a stronger change-agent than habitat loss,” Breed said. “Protecting habitat remains a key management strategy, and that may help some butterfly species. However, for many others, habitat protection will not mitigate the impacts of warming.”

Bonus: Read about how butterflies serve as inspirations for engineers creating new technologies in a new story from our Style and Design Issue.

Photinus pyralis, a species of firefly found in the eastern United States (via Terry Priest / wikimedia commons)

What’s more magical than a firefly light show on a warm summer night? Just remember that if you catch fireflies, you can keep them in a jar (with a lid punched to let in air and a moistened paper towel on the bottom) for only a day or two before you need to set them free.

(1) There are more than 2,000 species of fireflies, a type of beetle. Despite their name, only some species produce adults that glow. Fireflies in the western United States, for example, lack the ability to produce light.

(2) Males that do glow use their flash to attract females. Each species has its own pattern of light flashing.

(3) In some places at some times, fireflies synchronize their flashing.

(4) Firefly light can be yellow, green or orange.

(5) Firefly larvae may glow, even some that live underground or under water. They use the light to communicate to predators that they aren’t tasty (they produce unpalatable, defensive steroids for protection).

(6) Larvae are carnivorous and particularly enjoy snails. Adult fireflies usually live off of nectar and pollen, but some don’t feed at all.

(7) A few firefly species are also carnivorous as adults. They don’t eat snails, though—they eat fireflies of other genera.

(8) Fireflies are among the many species that are bioluminescent, meaning that they can produce their own light.

(9) A chemical reaction within the firefly’s light organ produces the light—oxygen combines with calcium, adenosine triphosphate (ATP—the energy-carrying molecule of all cells) and a chemical called luciferin, when an enzyme called luciferase is present.

(10) The light is the most efficient light in the world. Nearly 100 One hundred percent of the energy in the chemical reaction is emitted as light.

(11) Luciferase has proven to be a useful chemical in scientific research, food safety testing and forensic tests. It can be used to detect levels of ATP in cells, for example.

(12) When luciferase was first discovered, the only way to obtain the chemical was from fireflies themselves. Today, synthetic luciferase is available, but some companies still harvest fireflies, which may be contributing to their decline.

(13) Other factors that may be contributing to firefly decline include light pollution and habitat destruction—if a field where fireflies live is paved over, the fireflies don’t migrate to another field, they just disappear forever.

(14) Observing fireflies in your backyard can help scientists learn more about these insects and why they’re disappearing.

A new study uses high-speed videography to examine how mosquitoes survive the impact of raindrops. Photo courtesy of the Georgia Institute of Technology

Summer’s here. Along with barbecues, beach excursions and baseball games, that also means the arrival of a particularly unwelcome visitor—the mosquito.

But as we cringe, imagining the hordes of mosquitoes that will bother us shortly, we’ve also got to hand it to them—they’re remarkable hardy creatures, resisting all manner of sprays, repellents, candles and anything else we throw at them. And one of their most amazing abilities is that they can remain in flight in the midst of one of nature’s own attacks: a falling raindrop.

For a mosquito, getting hit with a raindrop is the equivalent of a human getting hit by a 3 ton object—something roughly the size of a pickup truck. An individual raindrop is about 50 times the mass of a mosquito, and the drops fall at speeds as fast as 22 miles per hour. Yet the tiny insects are able to survive countless collisions during the course of a storm, when these truck-sized hazards are plummeting all around them.

How do they do it? According to a study published earlier this week in the Proceedings of the National Academy of Sciences, it is the mosquito’s tiny size—along with a zen-like approach of passive resistance—that allows it to stay in flight despite these massive collisions.

Mosquitoes, it turns out, combine an extremely strong exoskeleton with a minuscule mass to minimize the force of each raindrop when it hits. The fact that they are so much lighter than the raindrops means that the drops lose very little momentum when they collide with the mosquitoes, which translates into very little force expelled onto the insect.

Additionally, instead of standing strong against the drops, or even trying to dodge them, mosquitoes simply go with the flow. ”As the raindrop falls, rather than resisting the raindrop, they basically join together kind of like a stowaway,” David Hu, an engineer at Georgia Tech and an author of the study, told NPR. “So as a result they get very, very little force.” The impact of the raindrop can knock the mosquito partly off course, but it doesn’t harm the insect nearly as much as it would if it were absorbed as a direct hit.

Moments after the mosquitoes latch on to the raindrops, they use their wings and long legs as miniature sails to lift themselves off the falling droplets before they crash into the ground, as shown in the video below. The main danger, the researchers found, is when mosquitoes are hit by raindrops when they are already close to the ground, because if they can’t dislodge in time, they’ll be slammed into the earth at the same speed as the falling drop.

How did the research group, led by Hu’s doctoral student Andrew Dickerson, figure out the mosquitoes’ strategy? ”Hitting a mosquito with a raindrop is a difficult experiment,” Hu said. “The first thing we did was drop small drops from the third floor story of our building onto a container of mosquitoes, and you can imagine that didn’t go very well. It’s kind of like playing the worst game of darts you can imagine.”

Eventually, the researchers brought the experiment inside, constructing an acrylic mesh cage to contain the mosquitoes that would also permit the entry of water drops.

Better understanding how insects deal with nasty weather could help engineers in designing biologically-inspired micro air vehicles, like the Nano Hummingbird, above

They then hit the insects with tiny jets of water to simulate the velocity of falling raindrops, and filmed six Anopheles mosquitoes entering the water stream. They used a high-speed camera that captured 4000 frames per second (a typical video camera captures 24 frames per second). All six of the insects survived, and the footage—along with theoretical equations—allowed the scientists to better understand the insects’ remarkable ability to deal with rain.

The experiments were also conducted with an eye towards practical engineering. The design and construction of micro air vehicles (MAVs)—tiny robotic aircraft that could potentially be used for surveillance and other purposes—is progressing in labs around the world. The California company AeroVironment has developed a hummingbird-inspired micro aircraft that weighs less than a AA battery, and other companies and research labs are currently looking into making even smaller autonomous aircraft. Better understanding how natural life evolved to fly in the rain, the researchers note, might help us design our own tiny crafts to stay aloft in the elements as well.

A new study shows that over-the-counter products sold to eradicate the bed bug, shown feeding above, are relatively ineffective

First comes a mysterious difficulty sleeping through the night, then a splotchy, itchy rash and finally the alarming (and somewhat embarrassing) realization—your bed is infested with Cimex lectularius, the dreaded bed bug.

A new study published yesterday in the Journal of Economic Entomology has more bad news for those suffering from an infestation: Over-the-counter products like “foggers” and “bug bombs” do virtually nothing to kill the irritating pests.

Bed bugs have afflicted humans for a long time—they were even mentioned in the writings of Aristotle and Pliny the Elder—and a number of natural remedies have been used around the world, from black pepper to wild mint to eucalyptus oil. In the years after World War II, bed bugs were nearly wiped out in Western countries by heavy use of pesticides. Since the late 1990s, though, they have come back with a vengeance.

Scientists are unsure why they’ve made a comeback in recent years, but increased international travel and the bugs’ resistance to pesticides are suspected culprits. Bed bugs are especially likely to spread in densely populated cities and apartment buildings—and once they’ve infested your bed, as bed bug sufferers know well, they’re extremely difficult to eradicate. The tiny bugs, just 4 to 5 millimeters in length, can live for up to a year without feeding, and their eggs can lodge invisibly in the seams of sheets or pillowcases.

Most infestations are detected when the creatures do begin to feed, piercing the skin to suck out blood and leaving a series of telltale blotchy red marks. Since bed bugs can become fully engorged with blood in just a few minutes while you’re asleep, catching one in the act is extremely rare. Infestations can also be detected by a characteristic smell, similar to that of over-ripe raspberries, and pest control companies often use dogs to recognize the odor.

The new study, by Susan Jones and Joshua Bryant of Ohio State University, evaluated consumer bed bug control products. They tested the effectiveness of three different products on a five bed bug populations collected from the field, and the results were consistently dismal: The bugs showed essentially no adverse effects after two-hour exposures to the spray insecticides. One population did show an increase in mortality, but only when the bugs were directly hit by the spray, something the authors say is exceedingly rare in real-life applications since the bugs burrow deep into mattresses and fabrics.

“These foggers don’t penetrate in cracks and crevices where most bed bugs are hiding, so most of them will survive,” Jones said in a press release. “If you use these products, you will not get the infestation under control, you will waste your money, and you will delay effective treatment of your infestation.”

One reason the the products are so ineffective, the authors speculate, is an especially concerning one: pesticide resistance. Excessive use of products such as these, which contain the pesticide pyrethoid, might be causing more and more bed bugs to become entirely resistant to the same chemicals that used to wipe them out easily.

So what are you to do if hit with a bed bug infestation? Bringing in a pest professional to kill the creatures is likely more effective than using the store-bought products, but increasing resistance can also render this approach ineffective. Oftentimes exterminators will recommend that you throw out mattresses and other pieces of furniture that bed bugs have infested. Using extreme cold or heat to kill the bugs is an increasingly popular solution, but these techniques also sometimes leave behind founder populations that generate an infestation afterward.

The bottom line—once an infestation of bed bugs has taken hold, it’s extremely difficult to get rid of. Experts advise that early detection and immediate treatment by professionals is the best chance you have of eradicating it entirely. But buying a pesticide over-the-counter and hoping for the best really doesn’t work.

Acanthaspis petax, a type of assassin bug, stacks dead ant bodies on its back to confuse predators. Photo by Mohd Rizal Ismail

Imagine you’re wandering in the forests near Lake Victoria, in Kenya or Tanzania, when you spot something strange crawling on a leaf. It looks like a dozen or so ants, stuck together in a ball. But look more closely and you’ll see the ants are dead. And there’s a nasty-looking insect underneath, hauling these ants corpses along like a miniature backpack.

This is Acanthaspis petax, a member of the Reduviidae family, which is found in East Africa and Malaysia. Like other assassin bugs, it hunts its prey by piercing it with its proboscis, injecting paralysis-inducing saliva and an enzyme that dissolves tissue, then sucking out the innards. But unlike other bugs, it then fashions empty ant exoskeletons into protective outerwear. The insect can carry as many as 20 dead ants at a time, and binds them together with a sticky excretion into a cluster that may be larger than its own body.

For years, scientists debated why Acanthaspis petax engaged in this unusual behavior. It hunts several different types of prey, but appears to exclusively stack ant bodies on its back. Some suggested that the ant corpses may provide olfactory camouflage when hunting, while others thought the mound of bodies may be used as a visual distraction for larger creatures that are hunting the assassin bug.

Photo by Mohd Rizal Ismail

In 2007, a team of researchers from New Zealand carried out an experiment to test whether the insect’s corpse-carrying strategy truly helped protect it from predation. In the study, they left assassin bugs alone in glass cages with several species of jumping spiders, which are their natural predators. Some of the insects were carrying balls of ant carcasses on their backs (the researchers called these “masked” bugs) while others were left naked. Since the jumping spiders have excellent vision but a poor sense of smell—they hunt by using their acute sense of sight to make a precisely gauged leap and land on their prey—the experiment would indicate if the ant bodies served as visual camouflage or not.

The result: the spiders attacked the naked bugs roughly ten times more often than the masked ones. The researchers even repeated the experiment with dead, preserved assassin bugs, to control for the effects of movement and behavior, and the results remained the same. Carrying that ball of dead ants, it turns out, is a great strategy for the assassin bug to use in trying to survive for its next meal.

The scientists speculate that the large mound of corpses changes the visual form of the insect to the point where the spiders can’t recognize it as prey.

But why do the assassin bugs refrain from using other insects in the same way? The researchers suggest that Acanthaspis petax may actually be relying on the spiders’ inherent reluctance to attack ants. Because ants have a tendency to swarm and may secrete chemical weapons, the spiders don’t typically hunt them.

Good strategy for Acanthaspis petax. Raw deal for the ants.