Posts Tagged ‘Bees’

Honeybees can identify a piece of paper with zero dots as “less than” a paper with a few dots. Such a feat puts the insects in a select group—including the African grey parrot, nonhuman primates, and preschool children—that can understand the concept of zero, researchers report June 7 in Science.

“The fact that the bees generalized the rule ‘choose less’ to [blank paper] was consequently really surprising,” study coauthor Aurore Avarguès-Weber, a cognitive neuroscientist the University of Toulouse, tells The Scientist in an email. “It demonstrated that bees consider ‘nothing’ as a quantity below any number.”

In past studies, researchers have shown that bees can count up to five, but whether the insects could grasp more-complex ideas, such as addition or nothingness, has been unclear. In the latest study, Avarguès-Weber and her colleagues tested the bees’ ability to comprehend the absence of a stimulus by first training the insects to consistently choose sheets of paper either with fewer or more dots by landing on a tiny platform near the paper with the dots. If the bees chose correctly, they were rewarded with a sugary drink. The bees performed the task surprisingly well, Avarguès-Weber says. “The fact that they can do it while we were also controlling for potential confounding parameters confirms their capacity to discriminate numbers.”

The team then tested the bees’ ability to distinguish a blank piece of paper, or what the researchers call an empty set, from a sheet with one dot and found the insects chose correctly about 63 percent of the time. The behavior reveals “an understanding that an empty set is lower than one, which is challenging for some other animals,” the researchers write in the paper.

That bees can use the idea of “less than” to extrapolate that nothing has a quantitative nature is “very surprising,” says Andreas Nieder of the University of Tübingen in Germany who was not involved in the study. “Bees have minibrains compared with human brains—fewer than a million neurons compared with our 86 billion—yet they can understand the concept of an empty set.”

Nieder suggests honeybees, similar to humans, may have developed this ability to comprehend the absence of something as a survival advantage, to help with foraging, avoiding predation, and interacting with other bees of the same species. The absence of food or a mate is important to understand, he says.

Clint Perry, who studies bees at Queen Mary University of London and was not involved in the study, is a bit more cautious about the results. “I applaud these researchers. It is very difficult to test these types of cognitive abilities in bees,” he says. “But I don’t feel convinced that they were actually showing that the bees could understand the concept of zero or even the absence of information.” Perry suggests the bees might have selected where to land based solely on the total amount of black or white on each paper and that’s the choice that got rewarded, rather than distinguishing the number of dots or lack of them.

Avarguès-Weber and her colleagues argue, however, that the bees were always rewarded when shown dots. “In the test with zero (white paper) versus an image with a few dots, the bees chose the white picture without any previous experience with such stimulus. A choice based exclusively on learning would consist in choosing an image similar to the rewarded ones, ones presenting dots,” she says.

Perry says he’d like to see better control experiments to confirm the finding, while Nieder is interested in the underlying brain physiology that might drive the how the insects comprehend nothingness. How the absence of a stimulus is represented in the human brain hasn’t been well studied, though it has been explored in individual neurons in the brains of nonhuman primates. It could be even harder to study in bees, because they have much smaller brains, Nieder says. Setting up the experiments to test behavior and record brain activity would be challenging.

Avarguès-Weber and her colleagues propose a solution to that challenge—virtual reality. “We are developing a setup in which a tethered bee could learn a cognitive task as done in free-flying conditions so we could record brain activity in parallel,” she says. The team also plans to test the bees’ potential ability to perform simple addition or subtraction.

S. Howard et al., “Numerical ordering of zero in honey bees,” Science, doi:10.1126/science.aar4975, 2018.

https://www.the-scientist.com/?articles.view/articleNo/54776/title/Bees-Appear-Able-to-Comprehend-the-Concept-of-Zero/

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By Sarah Fecht

You’ve probably heard the news that our nation’s bees are in trouble. Pollinators have been disappearing for decades, and the population crash could threaten the global food supply. Now, a small city in Iowa has decided to do something about it.

This spring, Cedar Rapids (population: 130,000) will seed 188 acres with native prairie grasses and wildflowers. The city’s plan is to eventually create 1,000 acres of bee paradise by planting these pollinator-friendly foodstuffs.

Scientists think the pollinator crisis is caused by a variety of factors, including pesticides, pathogens, and climate change. Meanwhile, with farms, parking lots, mowed lawns, and other human developments replacing wildflower fields, bees have been losing habitat and their food supply. While many of the drivers behind bee population decline remain mysterious, the people of Cedar Rapids hope to at least give pollinators places to perch and plants to feed on.

The 1,000 Acre Pollinator Initiative (http://www.cedar-rapids.org/residents/parks_and_recreation/pollinator_and_natural_resources_initiatives.php#Acre) grew out of a partnership with the Monarch Research Project(MRP), whose goal is to restore monarch butterfly populations. It was Cedar Rapids Park Superintendent Daniel Gibbins who proposed converting 1,000 acres into pollinator habitat over five years. So far, the project has secured $180,000 in funding from the state and the MRP.

“With the agricultural boom around 100 years ago, about 99.9 percent of all the native habitat of Iowa has been lost,” says Gibbins, who is spearheading the project. “When you convert it back to what was originally native Iowa, you’re going to help a lot more than just native pollinators. You’re helping birds, amphibians, reptiles, mammals—everything that’s native here relies on native vegetation.”

Prairie revival

Cedar Rapids has developed a special mix of grasses and wildflowers to help restore that native habitat. The seed mix includes 39 species of wildflowers, and 7 species of native prairie grasses. While bees and butterflies are mostly attracted to the flowers, the hardy prairie grasses will prevent weeds and invasive species from moving in and choking out the flowers.

Gibbins and his team have catalogued all the unused public land where they could potentially plant the flowers and grasses. The list includes not only the rarely frequented corners of parks, golf courses, and the local airport, but also sewage ditches, water retention basins, and roadway right-of-ways, totaling nearly 500 acres. Cedar Rapids is working with other cities within the county to reach its 1,000-acre target.

Before they can seed the land with the special pollinator plant mix, Gibbins’ crew has to “knock back the undesirable vegetation.” That means mowing down, burning off, or in some cases applying herbicide to get rid of grass, weeds, and invasive species. They’ll lay down the special seed mixture in the spring and fall.

“You can’t just seed them and walk away,” says Gibbins. Although the pollinator habitat will be lower maintenance than a green turf that needs to be mown every week, the prairie grasses will require some care, including mowing once a year or burning every few years.

Everyone can help

You don’t need to have 1,000 spare acres to help bees and butterflies. Even devoting a few square feet of your garden—or even a few small planters—to wildflowers native to your area could make a difference, says Gibbins.

“When creating pollinator gardens, the most important thing is to have a big diversity of wildflowers and heirloom crops that bloom in the spring, summer, and fall,” says Stephen Buchmann, a pollination ecologist at the University of Arizona and author of The Reason for Flowers. (Buchmann isn’t involved in the 1,000 Acre Initiative.)

Buchmann recommends against using herbicides or insecticides, or, if necessary, applying them at night when bees aren’t active. Providing nesting sites for certain bee species can help, too.

“People think they’ll just plant the wildflowers and the bees will come,” he says. “And that’s true in some cases, but the smaller the bee is, the less far it can fly. Some can only fly a few hundred meters.”

Some species nest in hard substrates, like the bare ground (bees hate mulch, says Buchmann), or in holes that you can drill in adobe or earthen bricks. Others nestle in sand pits or dead wood that’s been tunneled through by beetles. And it helps to have mud and water on the premises. The Xerces Society has a handy how-to guide on creating homes for bees.

The 1,000 Acre Pollinator Initiative is still looking into funding for the next four years, and they don’t expect to see huge jumps in the number of pollinators immediately. But Cedar Rapids is confident it will help, and they hope the project will serve as a model for the rest of the country.

And if enough local businesses and private landowners get involved, there’s no reason to stop at 1,000 acres, says Gibbins. “There’s a big push to extend this initiative up to maybe 10,000 acres in Linn County.”

http://www.popsci.com/Cedar-Rapids-Iowa-save-bee-pollinator#page-4

Bumblebees use information from surrounding electric fields to make foraging decisions.

However, how they detect these fields has been a mystery – until now.

Mechanosensory hairs may explain how bumblebees sense electric signals transmitted by flowers, says a team of scientists at the University of Bristol, UK.

Focusing on the buff-tailed bumblebee (Bombus terrestris), Bristol scientists tested two potential mechanisms that would allow the insects to detect electric fields through the insulating medium of dry air: deflections of either the antenna or hairs.

Using a laser to measure vibrations, they found that both the antenna and mechanosensory hairs deflect in response to an electric field, but the hairs move more rapidly and with overall greater displacements.

They then looked at the bumblebees’ nervous system, finding that only the hairs alerted their nervous system to this signal.

“This ability may arise from the low mass and high stiffness of bumblebee hairs, the rigid, lever-like motion of which resembles acoustically sensitive spider hairs and mosquito antennae,” the researchers said.

Noting that mechanosensory hairs are common in arthropods, they suggest that electroreception could be a widespread phenomenon that provides insects with a variety of currently unrecognized abilities.

“We were excited to discover that bumblebees’ tiny hairs dance in response to electric fields, like when humans hold a balloon to their hair,” said lead author Dr. Gregory Sutton from the University of Bristol’s School of Biological Sciences.

“A lot of insects have similar body hairs, which leads to the possibility that many members the insect world may be equally sensitive to small electric fields.”

“Scientists are particularly interested in understanding how floral signals are perceived, received and acted upon by bees as they are critical pollinators of our crops,” he added.

“Research into these relationships has revealed the co-evolution of flowers and their pollinators, and has led to the unraveling of this important network which keeps our planet green.”

The team’s findings have been accepted for publication in the Proceedings of the National Academy of Sciences.

http://www.sci-news.com/biology/bumblebees-hairs-detect-floral-electric-fields-03909.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+BreakingScienceNews+%28Breaking+Science+News%29