The declining bee population: Does chlorine in a swimming pool have anything to do with it?

Chlorine? 

Ever since PBS NewsHour correspondent Spencer Michels interviewed Extension apiculturist Eric Mussen of the UC Davis Department of Entomology and several other UC scientists and bee folks on the declining honey bee population, it's been busy on the bee front.

Everyone seems to have a theory on the cause of colony collapse disorder (CCD) and why the bee population is declining.

One person, known as "DK," posted a comment on the PBS NewsHour site that maybe chlorine has something to do with it.

"Every morning, when I sweep (skim) the family pool here in Sherman Oaks (Los Angeles), Calif., at least 3-4 bees from a hive in a nearby hedge are dead in the water, and I don't think it's from drowning," DK wrote. "It's like the La Brea Tar Pits were eons ago:  The sparkling pool looks like potable water, but it just lures them to their deaths...When I "googled" this subject, it turned out a farmer in the San Joaquin valley who was experiencing colony collapse discovered that a neighboring farmer was using a chlorine based pesticide in his irrigation water on the adjacent watermelon patch; when I read further into it, the article said chlorine was a suspected 'neuro-toxin" for the bees, and that corresponds with my empirical observations.  The chemical component also might explain why only 25% of bee colonies are experiencing this problem."

"So, scientists in northern California and elsewhere, that's your clue:  CHLORINE (and its derivatives).  It's worth a look."

Mussen, a noted expert on honey bees, responded:

"I read with interest your concern about a possible connection between chlorine and our honey bee problems.  I believe that you are correct that honey bees actually prefer a bit salty water to pure water, so they might be attracted to your swimming pool water.  However, honey bees do not like to get their feet wet when collecting water, if they can help it.  They stand on the dry and drink from the film of water caused by capillarity.  If you find one drinking water near your pool, on the poll apron, pool wall or a floating toy, check their behavior.

"The bees you find in the pool probably were not there for drinking purposes.  You noted that you have a colony living nearby.  Each day that colony raises about 1,000 newly emerging adult workers and around six weeks later those 1,000 bees will die of old age.  They do not die in the hive.  They tend to keep foraging until they flutter to the ground (lawn, driveway, sidewalk, pool, etc.) wherever they may be.  Those bees are not yet dead, so for a little while they still can sting if bumped against or stepped on.  That is most likely why they keep ending up in your pool.

"In reference to your statement about chlorine in pesticides harming a beekeeper's bees, there have been a succession of pesticides with chlorine incorporated into their structures that are toxic to bees.  The group named organochlorides are pretty much obsolete, but a new group of chemicals, called neonicotinoids, have a chlorine in them.  Beekeepers fear those compounds because they become systemic in the plants and are found in the nectar and pollen when the plants bloom.  Recently, the systemics have been delivered in irrigation water, since they can be picked up from the soil by the plant roots.  In 'chemigation' with underground emitters, you would think that the chemicals would stay away from the bees.  But, the systems leak and the bees will forage at the junctions in the pipes and from puddles on the ground.  So, the bees get the chemical at field delivery concentrations, not at the much reduced concentrations that end up in the blossoms."

Speaking of water, as any beekeeper will tell you, bees don't like to get their feet wet.  Honey bees don't dive into a pool on a hot summer day. They don't head for the sprinklers for a quick shower. They don't stand in water.  When they collect water to cool their hives, they stand on the very edge of a water-filled container, such as a birdbath or the lip of a flower pot.

Which reminds us: a recently published children's book (for ages 4 to 10) about honey bees seemed to have it all: colorful illustrations, catchy lines, and educational information about bees.

One look at an illustration, though, and it's apparent that neither the author nor the illustrator know that much about water and honey bees. The illustration clearly shows honey bees walking in water. Three of them. Three of them happily walking in a water-filled birdbath.

"What's wrong with this illustration?" I quizzed a veteran beekeeper. He looked at me as if I'd just asked him the second letter of the alphabet.

"Bees," he said, "don't like to get their feet wet. Those bees in that illustration are walking in water. They don't do that."

No, they don't.

If you're gearing up for the Fourth of July weekend, you'll probably head to the farmers' market, a roadside stand, or the produce department of your favorite grocery store for some freshly picked strawberries.

And you can thank a honey bee if your berry is fully formed. If it looks deformed "or not quite filled out," possibly "the seeds on that side didn't get pollinated," said Extension apiculturist Eric Mussen of the UC Davis Department of Entomology faculty.

Among the fruits  and vegetables that require bee pollination are almonds, (seeded) citrus, plums, cherries, apples, kiwi. melons, squash, pumpkin, blackberries, blueberries, raspberries and vegetable seeds such as onion seeds.

The Häagen-Dazs Honey Bee Haven, a half-acre bee friendly demonstration garden at the Harry H. Laidlaw Jr. Honey Bee Research Facility at the University of California, Davis, showcases a number of plants that require bee pollination, including almonds, apples, plums, blueberries, onions and squash. The garden, located on Bee Biology Road, west of the central campus, is open to the public, year around, from dawn to dusk.

The goal of the bee haven is to provide a year-around food source for the bees at the Laidlaw facility, to raise public awareness on the plight of the honey bee, and to show visitors what they can plant in their own gardens to attract bees. And, it's a research garden. Native pollinator specialist Robbin Thorp, emeritus professor of entomology at UC Davis, is monitoring the dozens of different species of bees visiting the garden.

The strawberry patch is tiny--after all, this is a demonstration garden--but the berries are big.  Staff and volunteers keep the garden weeded and occasionally, harvest a few strawberries.

The verdict: Berry, berry fine!

Have you hugged your favorite pollinator today?

It's National Pollinator Week, and you're allowed to do that this week. Actually, any time you feel the inclination.

Honey bees, bumble bees, wool carder bees, leafcutter bees, sweat bees--they're all out there, ready for a hug.

'Course, they may misinterpret your actions.

This is the fifth annual Pollinator Week, when we pay tribute to bees, birds, butterflies, bats and beetles--and flies, too. Don't forget the flies. And all the other pollinators out there.

The U.S. Department of Agriculture is encouraging us to celebrate pollinators June 20-26. Perhaps what we should do, along with celebrating them, is vow to save them.

To attract honey bees to your garden, it's a good idea to let the artichokes flower.

Sure, you could pick them for your dinner, but you'd be depriving honey bees of theirs.

At the Häagen-Dazs Honey Bee Haven at UC Davis, the artichokes are beginning to flower. The haven, a half-acre bee friendly garden, is a demonstration garden planted next to the Harry H. Laidlaw Jr. Honey Bee Research Facility on Bee Biology Road.

It's open from dawn to dusk (no admission fee). The key goals of the garden are to provide bees with a year-around food source, to raise public awareness about the plight of honey bees, and to encourage visitors to plant bee-friendly gardens of their own. It also serves as a research garden.

The Häagen-Dazs Honey Bee Haven is a treasure, and fulfilling the needs of bees adds to that treasure.