bees – Page 2 – GOLLYGEE!

We all know that flowers attract bees and other pollinators to help them reproduce. And in this week’s Science magazine, we get more insight into how it’s done. As it turns out, bees use the electric fields around flowers to sense whether it might contain pollen. The bees can also tell by the electric field whether a flower has just recently been visited by another bee.

Plants tend to conduct electricity into the ground. This gives the flowers at the top a slight negative charge compared to the air around them. Bees on the other hand pick up positive charges as they fly around. These charges are caused by friction with the air and between body parts. When bees touch the flowers they attract the negatively charged pollen particles from the flowers. And the electric field of the flower is reduced so that when the next bee flies by it can tell that it has just been visited.

A computer model of the electric potentials around a flower

Researchers studied this phenomenon setting up electrically charged disks to stand in as flowers. Half of the disks contained sugared water and the other contained quinine, which is the bitter substance that gives tonic water it’s flavor. When the disks weren’t charged, bees landed on the disks at random landing on the bitter flowers just as often as the sweet ones. But when the sweet disk was charged, they visited it with 81% accuracy. They used the electric charge to hone in on the sweet “flowers”.

In addition to this, the plant conducts electricity, as the bee comes in closer proximity and eventually touches the flower. And once the bee leaves, the change in the plants electric field remains changed for about 2 minutes, as it build up negative charge again. During this period, the reduced electric field may serve as an indicator for other bees to know that the flower has just been visited so that they don’t stop by the pollenless plant.

Much more at the link, including how they use the electric field as an aid in determining shapes.

Source: D.Clarke et al. Detection and learning of floral electric fields by bumblebees. Science. Published online February 21, 2012

A study of honeybees has shown that a lack of sleep impairs their ability to recall recent events. From Scientific American:

After characterizing how honeybees find their way home when released in a new location, the scientists captured and then released bees in unfamiliar territory some 600 meters from their hive. In addition to tracking how long the bees needed to return home, the researchers monitored bee sleep. Bees take brief naps throughout the day in addition to longer periods of nocturnal sleep. (Snoozing bees are easy to spot because their antennae droop.) The scientists made their observations both by watching bees in person and by tracking their activity via radio-frequency devices that they glued onto some of the insects.

The researchers verified first that finding a new route home did not alter other foraging behaviors, although it did lead to an increase in sleeping time in the first part of the night. Curious as to whether this change might reflect some learning or memory process, the team decided to see what happens when bee slumber is disturbed by selectively placing the insects in a box that was gently agitated for about eight hours, making it difficult for them to relax and get a good night’s sleep.

The next day the researchers found that sleepless bees and well-rested ones performed no differently when left to find their way home from a novel location. In other words, lack of sleep apparently did not inhibit the bees’ learning processes. “This suggests that there are forms of learning that seem to be totally independent of sleep,” Menzel says.

The scientists observed, however, a significant and obvious difference when bees were brought to the new spot for a second day. This time, bees that had slept well found their way home faster and fewer got lost along the way than on the previous day. That observation indicates that the well-rested bees had learned from their experience the day before. Drowsy bees, however, took about as long to return home on the second day as on the first, and were just as likely to get lost.

The study appears in the Journal of Experimental Biology.

GOLLYGEE!

Tag: bees (page 2 of 2)

bees, flowers and electric fields

lack of sleep can effect memory