My name is Dr Margriet Dogterom and am the founder and owner of Beediverse. I write this blog for all who love bees and who want to learn more about these wonderful creatures.


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With every technique and system there is a good way to do it and there is a not so good way to do it.  It is the same for various techniques used to safely overwinter bee cocoons.  There are 3 main things to keep in mind when storing mason bees:

  • Keeping predators from eating bee cocoons
  • Preventing bee cocoons from drying out
  • Preventing bees from coming out earlier  and or in the wrong place (like a storage shed)

The easiest way to keep rodents away from eating the cocoons  is to store them inside a fridge.   To keep cocoons from dehydration inside a fridge place cocoons into a Humidity cooler.  But do check for water inside the humidity cooler.  An alternative is to store them outside.  If outside storage is preferred, keep cocoons in a cookie tin with a f

Mason Bee cocoon humidity cooler

Mason Bee cocoon humidity cooler

ew airholes in the lid.  The metal tin will prevent predation.  Outside storage only works however until temperatures warm up.  The cocoons will have to be moved to the mason bee home for release as spring arrives.  Cocoons set out under the attic of the Highrifridgese for example will be safe from dehydration and predation.  Releasing them from a Highrise or other home will make sure the bees emerge at the right time at the right location.

From the World of Bees 22 Jan.  Editor Fran Bach

“A chemical that is thought to be safe and is, therefore, widely used on crops — such as almonds, wine grapes and tree fruits — to boost the performance of pesticides, makes honey bee larvae significantly more susceptible to a deadly virus, according to researchers at Penn State and the U.S. Department of Agriculture.

“In the lab, we found that the commonly used organosilicone adjuvant, Sylgard 309, negatively impacts the health of honey bee larvae by increasing their susceptibility to a common bee pathogen, the Black Queen Cell Virus,” said Julia Fine, graduate student in entomology, Penn State. “These results mirror the symptoms observed in hives following almond pollination, when bees are exposed to organosilicone adjuvant residues in pollen, and viral pathogen prevalence is known to increase. In recent years, beekeepers have reported missing, dead and dying brood in their hives following almond pollination, and exposure to agrochemicals, like adjuvants, applied during bloom, has been suggested as a cause.”

According to Chris Mullin, professor of entomology, Penn State, adjuvants in general greatly improve the efficacy of pesticides by enhancing their toxicities.

“Organosilicone adjuvants are the most potent adjuvants available to growers,” he said. “Based on the California Department of Pesticide Regulation data for agrochemical applications to almonds, there has been increasing use of organosilicone adjuvants during crop blooming periods, when two-thirds of the U.S. honey bee colonies are present.” Fine noted that the U.S. Environmental Protection Agency classifies organosilicone adjuvants as biologically inert, meaning they do not cause a reaction in living things.

“As a result,” she said, “there are no federally regulated restrictions on their use.”

To conduct their study, the researchers reared honey bee larvae under controlled conditions in the laboratory. During the initial stages of larval development, they exposed the larvae to a low chronic dose of Sylgard 309 in their diets. They also exposed some of the larvae to viral pathogens in their diets on the first day of the experiment.

“We found that bees exposed to the organosilicone adjuvant had higher levels of Black Queen Cell Virus,” said Fine. “Not only that, when they were exposed to the virus and the organosilicone adjuvant simultaneously, the effect on their mortality was synergistic rather than additive, meaning that the mortality was higher from the simultaneous application of adjuvant and virus than from exposure to either the organosilicone adjuvant or the viral pathogen alone, even if those two mortalities were added together,” said Fine. “This suggests that the adjuvant is enhancing the damaging effects of the virus.”

The researchers also found that a particular gene involved in immunity — called 18-wheeler — had reduced expression in bees treated with the adjuvant and the virus, compared to bees in the control groups.
“Taken together, these findings suggest that exposure to organosilicone adjuvants negatively influences immunity in honey bee larvae, resulting in enhanced pathogenicity and mortality,” said Fine.

The results appeared Jan. 16 in Scientific Reports.

Mullin noted that the team’s results suggest that recent honey bee declines in the United States may, in part, be due to the increased use of organosilicone adjuvants.

“Billions of pounds of formulation and tank adjuvants, including organosilicone adjuvants, are released into U.S. environments each year, making them an important component of the chemical landscape to which bees are exposed,” he said. “We now know that at least Sylgard 309, when combined at a field-relevant concentration with Black Queen Cell Virus, causes synergistic mortality in honey bee larvae.”

Read more…


News from the World of Bees  14 Jan 2017

Neonicotinoids — the most widely used class of insecticides — significantly reduce populations of predatory insects when used as seed coatings, according to researchers at Penn State. The team’s research challenges the previously held belief that neonicotinoid seed coatings have little to no effect on predatory insect populations. In fact, the work suggests that neonicotinoids reduce populations of insect predators as much as broadcast applications of commonly used pyrethroid insecticides.  Direct from Penn state web site.  Read more….

This received via Dave Stocks at the Gilroy, CA, ‘The Buzz’, reprinted
there from Bee Thinking, which took it from the online publication


Living on a mountain is hard for bees and flowers. It’s cold. There’s
extreme weather. And new research has found it getting even harder for
both flowers and bees to make a living in alpine environments lately.
Scientists compared over 40 years of mountain bumblebee and flower records
on three Colorado mountains and found major decreases in both bees and
flowers. But they also found clear evidence of rapid evolution by the bees,
suggesting it.s not time to give up on mountain bumble bees just yet.
Entomologists and botanists get teased about traveling the world, meeting
interesting insects and plants, and then killing them. But it’s a morbid
habit that pays off; it creates a long-term, stable record of the
biological past. Museum collections may look like a creepy charnel house to
outsiders, full of corpses, pins, and mothballs. Our libraries of dead
things become a book of evolutionary change for future scientists to read.

Preserving organisms from taxonomic or ecological studies lets us travel
back in time. People are always interested in having their data looked at
and reanalyzed in a different way, a way that they hadn’t thought about
previously. That is one of the great things about having open access data,
said Dr. Nicole Miller-Struttmann, lead author on the new bumble bee study.

To investigate how flowers and bumble bees changed, a team of scientists
dug through over 40 years of records. They tracked down thousands of bumble
bee specimens collected on mountains in Colorado between 1966 and 1980, and
compared them to bumblebees collected in the same areas between 2012 and
2014. They also used herbarium specimens of flowers collected during
similar time frames and surveyed flowers in the field.

Plants on mountains often have very narrow temperature tolerances; too much
heat can reduce flowering. On one of the mountains in the study, between
1960 to 1985, only 12 percent of the years were hot enough to reduce
flowering. Since 1985, 48 percent of years were too hot for flowers that
bumblebees typically forage on.

Since 1970, the total number of flowers available for bees on the mountain
study sites declined by 60 percent overall. What did that mean for bees?

Over 95 percent of bees in the study regions between 1966 and 1980 were
just two species of long-tongued bees. These bees specialize in flowers
with a narrow, elongated tubular shape. Their long tongue means they are
able to reach the nectar hidden at the bottom of a flower and can muscle
out their shorter-tongued relatives. This is an example of coevolution,
where two species reciprocally affect each other over evolutionary time.

Bees collected from 2012 to 2014 were different, though. The long-tongued
species of bumble bees declined by 24 percent. At the same time, warming
temperatures and changes in flowering plants allowed some lower altitude
bees to live at higher mountain elevations. The entire community of bumble
bees changed. Long-tongued bumble bees responded to the scarcity of flowers
by becoming less selective; the range of plants they foraged on changed
significantly and included flowers with no long nectar tubes.
The scientists wondered if the bees physically changed too, and measured
body length and tongue length on their historic and modern bee specimens.
How do you measure a bee’s tongue? Miller-Struttmann explains: They tuck
their tongue back into their body, so they sort of fold it back up along
their chin, I guess you could say. We had to re-hydrate historic specimens,
and then fold the tongue out, and then measure it under a microscope with

What no one expected was that the tongues of long-tongued bees would get
shorter. A lot shorter.  A 24 percent decrease in tongue length is really
dramatic, says Miller-Struttmann. That was in 40 years, in 40
generations, I should say, because these bumblebees only have one
generation a year. That’s a pretty short period of time to see such a
dramatic shift. Bumble bee bodies also got slightly smaller, but not as
much as the tongues shrank. The research team did not find changes in the
depth of the flowers bumble bees were visiting. The bees shape changed,
but the flowers didn’t.  Building and maneuvering a big tongue takes energy, and bees with shorter
tongues may have done better at diverting that energy into more babies. In
the short term, the bumble bees seem to be hanging on. But what about
longer term?

Right now, bumblebees and the plants they historically fed on are
mismatched physiologically. The bees may not be as good a pollinator for
those plants, which could cause further declines in flowers. In the long
term, perhaps they will also evolve, but they’re much longer-lived species.  Their generation time is decades, not yearly. Change will be slower or may
not happen at all.

Dr. David Inouye has researched flowers and alpine bees at the Rocky
Mountain Biological Laboratory for decades. He said, This study is a great
example of the value of archiving data an example of a change in bumble
bees that is unexpected, and would not have been discovered without access
to historical data. We have evidence from elsewhere in the Rocky Mountains
that bumble bee queens of eight species have moved up 230 m in altitude over
about the same time span, and these kinds of changes in bumble bee
communities will have interesting consequences over both ecological and
evolutionary time scales.

This study also highlights a common problem for mountain or other remote
refuges as the climate warms, the places where plants and animals=
thrive move slowly away from the areas we’ve designated for their conservation. By
increasing areas set aside for nature, or making sure we have connections
between isolated nature refuges, we can try to help bees and plants adapt
to our new warmer world.


News from the world of bees Nov 29th 2016

Do you know where your food comes from? If you enjoy crisp apples, juicy tomatoes, and plump berries, thank a farmer, thank a scientist, and thank a bee. We need strong, healthy and diverse bee populations to provide pollination for us to eat our most healthful food . While we can all thank a bee, the Penn State undergraduate students who received the 2016 Apes Valentes Undergraduate Research awards directly contributed to our understanding of how to keep bees healthy.

Read more…




Hi Margriet – when is your best guess as to when to put out the Bee Cocoons? I have had them in my outside storage shed all winter, but with the warmer weather as of late, and not much in the way of flowering trees, etc., I hate to have the Bees emerge too early, so I have placed them in a picnic cooler with ice packs, to simulate a cooler or colder climate. Let me know what you suggest. Thanks, Andy

Mason Bee cocoon humidity cooler

Mason Bee cocoon humidity cooler. Cocoons on one side and a moist pad on the other side of the divide.  Lid with 2 holes allows for air circulation  and containment of humidity.  Fridge temperature 2-4C.

Hi Andy, Yes the cooler will work in the short term.  For the longer term, use a humidity cooler inside a fridge.    A storage shed works until it warms up in late winter.   The simplest way of storing bees is in the attic of a bee home.  Bees will emerge when temperatures improve during the early spring.   But with experience, if you find that bees emerge earlier than fruit tree blossoms in your garden, then refrigeration inside a humidity cooler is the way to go.   Temperature inside the fridge needs to be between 2-4C.  If mason bees are kept in hibernation until late April- early May, fridge temperature needs to be  decreased to 1-2C. Dr Margriet.      Go to Humidity Cooler at Beediverse



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