The post got a surprising response and a lot of questions, more than I have time to answer on Facebook, so in this post I'll endeavour to answer a few and provide pointers to peer reviewed information sources.
What's the problem!?
The problem similar to the well documented role bird feeders play in the spread of disease amongst wild birds, open feeding brings bees together to feed and pathogens can easily be spread between them. Whilst it's not unusual for a bumblebee or honey bee colony to have some base level of viral, disease, and parasitic load which they're able to cope with. However current agricultural practices disease levels are being increased through Bumblebees imported for pollination. It's also been documented that there's been a rise in hobbyist beekeepers who lack the skill or ability to manage colonies and their contribution to increased hive mortality. With increased risks from escaped imported bumblebees with high viral loads or Honey Bees from sick, weak or otherwise compromised colonies it's easy for an open feeder to quickly become a reservoir for pathogens which healthy bees can then pickup from either the feeder or other bees using it.
Different bee species have their own parasites and diseases. As well as the various parasites for example Honey Bees have the devastating Varroa Destructor Mite and Varrooa Jacobsoni Mite, Osmia have pollen mites, Bumblebees have a huge range of mites and internal parasites they also have their own diseases. A few years ago it's was discovered that Honey Bee diseases have actually spread to Bumblebees.Many of these diseases can't be treated, some are so dangerous that to control their spread whole Honey Bee hives need to be killed and burned - although Honey Bees have the help of someone hopefully monitoring their health, nobody reading this is monitoring disease load in wild Bumblebees or Solitary Bees.
Bumblebee being busy |
Doesn't the same thing happen with flowers?
A single flowerhead produces a miniscule amount of nectar hence bees having to visit so many of them. Compared to a flower a single feeder with a small amount of sugar water in it receives a massive amount of pollinator traffic. To give you some idea here's the figures:
A Canadian study identified that a Dandelion flower holds 7·4 µl (microlitres) of nectar.
A study in the Journal of Apicultural Science found Royal Crown Lavender (Lavendula Dentata) flowers hold an average of 0.68 µL of nectar.
A Sainsbury's plastic milk bottle top hold 11ml of fluid that's 11,000µL.
One milk bottle top, equivalent to 1486 Dandelion or over 16,000 Lavender flowers |
A good analogy for comparing a bee collecting nectar from a flower vs. syrup from a feeder would be to compare it to the difference between letting a friend try your drink on a night out versus you both gulping like crazy from a wheely bin full of something everyone else in the city has been putting their mouths to.
What about bees sharing a water source?
Honey bees gather water and providing a water source is an excellent way to help them. However Bees gather far less water than nectar so again a water source will also see far less traffic than a bee feeder with sugar water.. For example recently watching a pond next to a roughly 100,000 strong honey bee hive there there were only twenty bees actively gathering water. An open feeder with syrup in the same location would have drawn a few thousand bees from the same hive.
A Wildlife Pond located a few feet from a couple of busy hives |
It's only a little bit of syrup what harm can that do?
In case you skipped the boring numbers above one milk bottle lid is the equivalent of 1486 Dandelion or over 16,000 Lavender flowers. A milk bottle lid seems like nothing to us humans but to pollinators it's a huge food store.
But don't Beekeepers feed bees sugar water?
Yes indeed. However if used this is for a specific purpose and made in a specific concentration depending on the time of year and the weather. The purpose built feeder is placed inside the bee hive with an entrance accessible only to bees in that hive so bees from different colonies aren't feeding together. Weaker colonies will even have the hive entrances reduced in size to reduce the chance for other bees to rob them and make it easier for them to defend. Any information for Beekeepers about feeding bees be always includes an admonition against spilling syrup in the apiary.
Only the bees in the hive below this feeder can access the contents. A Hive Roof will go above it too. |
Open feeding seems pretty common in the USA, it's bad practice. Perhaps if they did less of it they wouldn't make so much prophylactic use of medications such a Terramycin which leaves England's Beekeepers scratching their heads. Here the Vetinary Medicines Directorate imposes four figure fines on anyone giving bees unlicensed unprescribed medicine.
What about reviving a tired bee with sugar water?
Giving a tired bee a little sugar water to revive it will is fine. If you're only feeding one bee she's not going to swapping pathogens with other bees. Just remember not to leave it out for other bees.
Inviting aggression
Another danger with open feeding Bees is your own safety. If Honey Bees encounter a readily available food source their behaviour changes and they go from foraging to robbing. After that first scout returns to the hive and tells her sisters about the free food robbing bees can arrive en masse and become aggressive and frantic as they try to take away as much food as they can before another colony does. Aside from fighting other bees there's also a pretty good chance you'll get stung if you're sat in your garden admiring the bee activity at your milk bottle top feeder.
Who forgot the flowers?
The other thing to remember is Bees are Pollinators. They pollinate plants whilst feeding. If instead of feeding from plants they're drinking sugar water from a plastic container that's a lot of plants not being pollinated and will led to a dearth of nectar the following year. Look again at the photo at the top of this page. There 5 milk bottle tops being used. With each holding 11ml of syrup each that's 55ml of syrup, the euivalent of almost 90,000 lavender flowers that aren't being pollinated by bees.
What about butterfly feeders?
In short: Dunno. Never used a Butterfly feeder, being a beekeeper and all. Presumably Butterflies face less imported exotic pathogens than bees as I doubt anyone's keen to import more caterpillars however I'd be concerned that a butterfly feeder baited with sugar water may be found by bees. Anyway if Butterflies are using a feeder they're not actually doing any pollinating.
So what can I do to help?
A lot of people genuinely want to help bees and there's a lot of ways to do this. The most obvious is to still to provide food, but not in the form of sugar water. Feed them the natural way, plant native flowering plants, and water them so they're able to provide nectar.
The natural way to feed Bees! |
A Mason Bee nest in the edge of a Honey Bee Hive. The young Mason Bees will emerge from those cocoons next Spring. |
Something particularly useful to Honey Bees is a Water Source. This can be as simple as a dustbin lid with water and some stones to land on. Birdbaths are also good for bees, typically having a wide edge to land on and whilst the water may look a little grotty after a couple of starlings have had a scrub the bees don't seem to mind. Near my hives I have wildlife ponds with plants and surfaces for bees to safely land on which is also great for biodiversity. One of the apiary ponds has newts and Damsel flies at the moment.
Honey Bee gathering water from a Wildlife Pond |
This was just a quick whistle stop tour of some of the dangers of open feeding bees and things you can do instead. I've intentionally not gone into detail about bee diseases as there's a lot of information already out there and unless you're a beekeeper you're unlikely to deal with them and if you are you should already know. Hopefully it will spread a little awareness and the next time someone posts a photo of an open bee feeder people will ignore it rather than endorsing it and reposting it 30,000 times. The bees have enough problems at present so try not to add to them.