Scientists have long wondered what exactly is killing bees in hives afflicted by colony collapse disorder (CCD), and now they may have found a clue. Bees in collapsing hives showed evidence of damaged ribosomes, which are crucial to protein production, according to a study published in the journal Proceedings of the National Academy of Science. The researchers suggest that an onslaught of viruses may be responsible for the cellular damage.
The findings suggest that CCD, which has been blamed on everything from viruses to fungi to pesticides, may be linked to problems with protein production that could make bees more susceptible to these threats. “If your ribosome is compromised, then you can’t respond to pesticides, you can’t respond to fungal infections or bacteria or inadequate nutrition because the ribosome is central to the survival of any organism. You need proteins to survive” [AP], said lead researcher May Berenbaum.
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Orchids have a clever way of attracting pollinators: By releasing the same pheromones honeybees give off to communicate with other hive-members in times of emergency.
[T]he bees are the favorite food of the larvae of Vespa hornets…[so] when the orchid Dendrobium sinense sends out these false alarms, the hornets pounce on the petals, thinking they’ll bring a bee dinner home to the kids [Scientific American]. The hornets leave hungry, but they help out the orchids in the process.
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Japanese giant hornets can wreak havoc on a hive of Japanese honeybees, slicing off the heads of worker bees, feeding on the hive’s honey, and carrying back the larvae to feed to their own young. But the native bees do have one effective defense against the giant marauders, and it’s a battle plan that uses the bees’ one clear advantage: numbers. When a hornet scout appears, hundreds of bees instantly swarm around the invader in what’s known as a “bee ball.” In a new experiment, researchers say they’ve determined exactly how the bee ball kills.
Previously, scientists thought that the heat generated by the mass of vibrating bees killed the hornet. But in the study, published in the journal Naturwissenschaften, researchers found that temperature alone can’t do the trick. The hornets “can survive for 10 minutes at a temperature up to 47C (or 116 degrees Fahrenheit), and the temperature inside the bee balls does not rise higher than 46C” [BBC News], says lead author Fumio Sakamoto. The researchers determined that increased carbon dioxide levels inside the bee ball also plays a role.
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Specialized cells found only on flower petals have the same basic function as nonslip mats that prevent people from slipping in the shower, a new study has determined. The bumpy cells, called conical cells, help bees come in for a landing on the flower petals and find their footing, so they can get down to the important business of pollination.
Conical cells had been something of a botanical mystery, with most researchers assuming they played a visual role. One hypothesis held that by modifying the spectral properties of the petal, the cells enabled the plant to appear brighter to pollinators [The Scientist]. In the study, will be published in a forthcoming issue of Current Biology, researchers showed that the conical cells’ main function is to provide friction, and that bees can detect them by touch. The first experiment used two kinds white snapdragons that looked identical to both human and bee eyes, but one was a mutant with flat cells instead of conical. The bees initially went to both flower types, but after 20 visits they chose the blossoms with conical cells more than 80 percent of the time.
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The concern over the declining honeybee population may be exaggerated, according to a controversial new study that shows their numbers are actually increasing globally. Alarm over a world pollination crisis is thus unfounded, say the researchers who analyzed Food and Agriculture Organization data and found that commercial domesticated bee hives have increased 45 percent in the past 50 years, to match growing demand for honey among a growing human population [AFP].
The study, published in Current Biology, says, “the declines in the U.S.A., some European countries and the former U.S.S.R. are more than offset by large increases elsewhere, including Canada, Argentina, Spain and especially China.” The study could help disprove a connection between regional declines, which have been attributed partly to parasitic mites and the general mystery known as colony collapse disorder, and a worldwide trend. But even if global bee populations continue to climb, researchers claim that there won’t be enough of them to go around. The real issue is not the honeybee numbers but the increasing work expected of them [CBC], the researchers argue.
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Honeybees have the ability to distinguish and remember visual quantities up to four, according to a new study. Researchers demonstrated that honeybees can match patterns containing the same number of icons, even when the icons are of mixed color and shape. This suggests that honeybees possess a basic number sense that was once thought to be exclusive to vertebrates. Researcher Shaowu Zhang says, “There has been a lot of evidence that vertebrates, such as pigeons, dolphins or monkeys, have some numerical competence but we never expected to find such abilities in insects. So far as these very basic skills go, there is probably no boundary between insects, animals and us” [Daily Mail]
To test the extent of the bees’ number sense, researchers set up a Y-shaped maze with a sweet treat at the end of one arm. In the training phase, bees entered the base of the maze through an entrance marked with either two or three dots. They had to remember this number when the maze forked into two paths— one marked with two dots, the other with three—in order to reach a sugar-water reward [Telegraph]. The 20 or so bees that were trained attained a success rate of 70 percent. Researchers then presented tougher challenges by increasing the number of dots. The bees could also distinguish between three and four dots, but were confused when even more dots were added.
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When a honeybee is given a dose of cocaine, it gets overexcited about poor-quality food and performs overenthusiastic dances to communicate with its hivemates, according to an odd new study that got bees hooked on drugs. The research found similarities between honey bees and humans, in that they are both are driven by rewards and both have their judgment altered by cocaine. “This is the first time that it’s been shown that cocaine has been rewarding to an insect” [Reuters], says study coauthor Andrew Barron.
After a honeybee has been out foraging for food, it returns to the hive and tells the other bees what it found by means of a “waggle dance” that describes the location and quality of the food source. But after dabbing low doses of cocaine on the bees’ backs before they went out, the researchers observed that when they returned they were more likely to dance for their nest mates, and performed particularly vigorous routines explaining where the food was located [The Guardian]. They performed these exuberant dances even when the food source that the researchers provided was a weak sugar water solution that didn’t merit the hive’s attention.
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Honeybees might deserve the title of the farmer’s best friend: A new study shows that not only do the busy insects pollinate flowers and make honey, they also scare away agricultural pests that like to chomp on the leaves of crop plants. Said the study’s coauthors: “Our findings indicate for the first time that visiting honeybees provide plants with a totally unexpected advantage…. They not only transport pollen from flower to flower, but in addition also reduce plant destruction by herbivores” [BBC News].
The bees act as inadvertent protectors of plants, researchers say. Caterpillars are constantly on the lookout for wasps, one of their main predators, and have delicate sensory hairs on their bodies that detect the air currents caused by a wasp’s beating wings. “These sensory hairs are not fine-tuned,” said [study coauthor] Jurgen Tautz…. “Therefore, caterpillars cannot distinguish between hunting wasps and harmless bees.” If an insect which they cannot identify generates air vibrations the caterpillars stop moving or drop away from the plant [Telegraph].
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Bumblebees that have a close encounter with a dangerous predator are still cautious and wary the next day, even though their trepidation slows them down as they forage for food. In a new study, researchers used robot spiders to briefly trap the bees and study their behavior afterwards, and found that in the end, some of the bumblebees get a little paranoid…. “They’re behaving as if they’re starting to see ghosts,” [co-author Lars] Chittka says [Science News].
The researchers used small robots to imitate the look and behavior of crab spiders, which are one of the major predators of bumblebees. They lie in wait in flowers which the bees need to visit to collect nectar, and are difficult to spot because they can change colour to match their surroundings [New Scientist].
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When a hummingbird or a hawk moth sups on the sweet nectar of a wild tobacco plant, they’re not just getting a tasty meal in exchange for their services in spreading the plant’s pollen. Instead, a new study shows that the nectar may be a complex chemical cocktail that simultaneously attracts and repels pollinators in order to optimize the amount of time they spend at each flower, and the attention they pay to flowers on different plants. “This paper shows just how sophisticated a plant can be in using chemistry to get what it wants,” [The Scientist] says lead researcher Ian Baldwin.
The researchers had already analyzed the chemical composition of tobacco plants’ nectar; they found that the compound benzyl acetone is the primary attractant, and that the plants “spike” their nectar with nicotine, presumably as a poisonous deterrent to insects. But in a clever experiment, the research team created genetically modified plants with different levels of these two chemicals. In greenhouse and field experiments, the scientists were surprised to find that not only did nicotine deter nectar robbers and plant nibblers, but the right dose prevented pollinators from lingering too long at any one flower, increasing the number of flowers visited [Science News].
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The commercial bumblebees that are brought to greenhouses to pollinate some vegetables occasionally wander off the job, and researchers say the wayward bees that slip out into the fields are infecting their wild cousins with a nasty parasite. A new study says that parasite may be to blame for the recent decline in wild populations in North America and elsewhere [New Scientist].
Greenhouse growers bring in the bumblebees for tomatoes and other crops that need what’s called “buzz pollination,” a strong vibration that shakes loose the pollen. Honeybees don’t give the buzz, but bumblebees do [Science News]. In the study, published in the journal PLoS ONE, researchers observed several greenhouses in Canada, and saw bumblebees flying out of the greenhouses through vents. When commercial bees landed on flowers in the nearby fields, researchers say they left behind parasites that wild bees later picked up. They found that half of the wild bees living near the greenhouses were infected with the parasite, while those that lived farther away were disease-free.
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The plight of honeybees got an official hearing in Congress last Thursday as farmers, scientists, and even Haagen-Dazs executives testified about the mystery of “colony collapse disorder,” which has been killing off honeybees since the fall of 2006. Beekeepers are getting desperate, but scientists still don’t know why more than one-third of U.S. hives were destroyed last winter. To make things worse, one promising avenue of research has just been debunked.
Researchers had recently zeroed in on a bee ailment called deformed wing virus as the culprit, and had hypothesized that the virus was being transmitted by a parasitic mite that’s been observed in failing hives. However, a new study published in the Journal of General Virology [subscription required] discredits that theory, finding that the virus does not grow within the mite. Instead, the infection has been found only inside the gut of the [parasite], suggesting that the mite has merely eaten it from the bodies of bees already infected [The Times].
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