Friday 21st of June 2019

the endangered flight of the bumblebee...



The beleaguered bumblebee faces a new threat, scientists say.

Researchers have found that two diseases harboured by honeybees are spilling over into wild bumblebees.

Insects infected with deformed wing virus and a fungal parasite called Nosema ceranae were found across England, Scotland and Wales.

Writing in the journal Nature, the team says that beekeepers should keep their honeybees as free from disease as possible to stop the spread.

"These pathogens are capable of infecting adult bumblebees and they seem to have quite significant impacts," said Professor Mark Brown from Royal Holloway, University of London.

Around the world, bumblebees are doing badly.

In the last few decades, many species have suffered steep declines, and some, such Cullem's bumblebee (Bombus cullumanus) in the UK, have gone extinct.

Scientists believe that the destruction of their habitats - particularly wildflower meadows - has driven much of this loss, but the latest research suggests that disease too could play a role.



Gus: I had not seen a bumblebee in years and when I saw one, I took a picture (see above — 2013)....


The Flight of the Bumblebee...

the combined stress factors...


Honey bees are quickly disappearing from the US – a phenomenon that has left scientists baffled. But new research shows that bees exposed to common agricultural chemicals while pollinating US crops are less likely to resist a parasitic infection.

As a result of chemical exposure, honey bees are more likely to succumb to the lethal Nosema ceranae parasite and die from the resulting complications.

Scientists from the University of Maryland and the US Department of Agriculture on Wednesday published a study that linked chemicals, including fungicides, to the mass die-offs. Scientists have long struggled to find the cause behind the Colony Collapse Disorder (CCD), in which an estimated 10 million beehives at an average value of $200 each have been lost since 2006.

Last winter, the honey bee population declined by 31.1 percent, with some beekeepers reporting losses of 90 to 100 percent of their bee populations. Scientists are concerned that “Beemageddon” could cause the collapse of the $200 billion agriculture industry, since more than 100 US crops rely on honey bees to pollinate them.

The new findings are key in determining one of the causes of the CCD, but they fail to explain why entire beehives sometimes die at once.


Insecticides — both those sprayed in the fields to control insects (those we call pests) and the insecticides used to manage the health of bee-hives against the varroa mite and fungus that spread faster than ever before — plus loss of habitat, that is to say loss of meadows where plants are varied and accessible to bees, not large fields of monocultures (bees usually operate within 150 metres from their hives though they can travel vast distances), plus changes in climatic conditions (UK experienced wettest winter on record in 2014 still with one week of wet weather to go to the end of winter — while California experienced its driest winter on record) — Plus varroa mites, fungus and other diseases that never affected bees before in such manner — ALL FACTORS THAT STRESS BEE POPULATIONS AT THE SAME TIME, reducing the ability of the bees to recover from this several-prongs "attack"... One stress factor may not destroy the bees, but several stress factors combined can have a deadly effect.


the flight of the bumblebee...



From Dr KarlDr Karl's Great Moments In Science


Many urban myths and half-truths roam our human consciousness. One oft-repeated fairytale runs that according to the laws of science, the bumblebee shouldn't be able to fly at all — indeed, not even be able to get off the ground. The reality is, as you probably guessed, that insects can fly — some as high as Mount Everest.

First, how did this story about the bumblebee pop into existence?

The typical sentence runs: "Didn't an aerodynamicist prove that bumblebees can't fly?"

According to John McMasters, who back in the 'good old days' was principal engineer on the aerodynamics staff at Boeing Commercial Aeroplanes, it seems the aerodynamicist of the myth was probably an unnamed Swiss professor famous in the 1930s and 1940s for his work in supersonic gas dynamics. The aerodynamicist was having dinner with a biologist. In the idle chit-chat, the biologist noted that bees and wasps had very flimsy wings — but heavy bodies. So how could they possibly fly?

With absolutely no hard data, but a willingness to help that overcame good dinner party etiquette, the aerodynamicist made two assumptions in his back-of-envelope calculations.

The first assumption was that the bees' wings were flat plates that were mostly smooth (like aeroplane wings). The second assumption was that as air flows over an insect's wings, it would separate easily from the wing. Both of these assumptions turned out to be totally incorrect — and the origin of our myth.

The aerodynamicist's initial rough calculations 'proved' that insects could not fly. But that was not the end of the story.

Of course, being a good scientist, his sense of curiosity got him interested in this problem. Clearly, insects can fly. He then examined insect wings under a microscope and found that they had a ragged and rough surface. In other words, one of his assumptions was way off.

But by then, overzealous journalists had spread the myth he had inadvertently created. The story had flown free, even though the bumblebee supposedly couldn't.

In fact, once our scientists began to look closely at how insects fly, they discovered astonishing details. For example, the aerodynamics used by flies gives them the amazing ability to do a right-angled turn in less than 50 milliseconds.

This problem of how insects fly was so hard to solve, that the mystery was solved only in the last 20 years.

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See articles above about insecticides and pesticides, and picture at top...