Friday, October 19, 2012

What Are Resistant Bees?

Over last couple days I've been reflecting on how the hives did this summer and wanted to note my observations around what happened with a particular hive.  This hive came close to dying out but somehow was able to recover, and I have a few thoughts on how it pulled off this feat.  First it is important to know that I inspect my hives often, despite any setbacks it may cause in the hives.  This allows me to document what is going on in the hive and collect data can be invaluable in identifying issues later on such as in this case.  Hive dynamics change so quickly that if you aren't watching weekly you can miss something unexpected that is worth looking into further, and I would encourage all beekeepers to take good notes during inspections.

To add some background here I need to define treatment free or survivor bees and how I use those terms vs how another beekeeper might define them.  I think of treatment free bees as bees that have been exposed to pathogens or parasites and survived without "help" from the beekeeper.  They would also have to be easy to work (not too aggressive), not prone to frequent swarming and good honey producers.  I put "help" in quotes because there are many things beekeepers may add to that definition as a result of trying to maximize a honey crop or pollination.  This also means that a hive in an isolated location that has survived without help for years and has tons of honey might not be very resistant but rather lucky that they haven't been exposed to anything yet.

The girls are working hard to store an abundance of pollen for spring.

This year has been an interesting year with the hives and seeing the damage that mites can cause.  The mites themselves do not directly kill the bees (their hosts), but rather steal energy/resources and spread diseases around the hive from bee to bee, similar to how mosquitoes spread Malaria.  When the bees are building up they can out-pace the mites by creating new bees faster than the mites can keep up and the hive stays healthy.  However after the flow ends mid-summer that pace slows down and an abundance of mites is left behind for a decreasing population of bees to deal with and viruses can quickly spread.  While there currently is nothing available to stop the viruses, there are ways to suppress the mites which in turn slows the rate they spread diseases.  One natural way bees indirectly suppress the mite levels is to swarm which causes a brood cycle break.  However beekeepers work pretty hard to prevent this to maximize the colony size and resulting honey surplus so we look to "treatments" or genetics to solve the mite problem.

Now that we know a little about what damage the mites are doing in the hive here is a summary of my observations of the Librarian hive this year.  This was a second year hive with a late season queen from 2011.  The hive suffered all spring and into July with high varroa levels and deformed wing virus (DWV).  The population was never able to build up and they dropped down to just a few frames of bees limping along on the stores collected the previous year.  However a rather surprising thing happened mid summer in that the varroa didn't go away but the DWV suddenly cleared up.  I had long given up on powdered sugar treatments and yet somehow this hive turned around when it should have perished and the queen was able to lay frames of healthy brood and the hive started thriving again.
This type of recovery has also been observed by other researchers but is not fully understood.  It appears that the bees are able to transfer genetic code to each other that makes them resistant to DWV or another virus.  This immunity is most likely transferred in the royal jelly nurse bees make and feed to the next generation of bees, which then become resistant and can pass it on again to the next.  Perhaps a little like how mothers transfer their immunity to viruses on to their children through breast milk.  Unfortunately the queen of this hive died suddenly last month and had to be replaced.  She was replaced by a queen from a hive that did great up until the end of July when it too was overtaken by DWV.  Unfortunately that hive and another one could not recover from the viral outbreak and dwindled to nothing in a matter of weeks.  Those hives both collapsed with symptoms that could be described as Colony Collapse Disorder (CCD).

Should this hive survive the winter and show signs that they have passed on DWV resistance to the bees raised in spring I have plans to explore how this resistance can be shared with other hives.  I also have the late season daughter queen from this hive with bees and frames that came form this hive that might also carry this resistance.  I do find the idea exciting that a mechanism may exist that doesn't solely rely on a queen passing on a genetic trait to the next generation.  Of course this also means that you could mistakenly think you have a queen line with resistant qualities when in fact the hive is thriving due to a an immunity that isn't passed on through daughter queens, but through the workers.

Dahlia blooms last until the first freeze in fall.

Crape Myrtle is another late September bloomer that the bees love. 

Hive checks (10/7/2012)

I've decided to give all the hives names this week so everyone is easier to keep track of.

Plum Creek
They have taken some syrup and they have good activity.  They have built up fairly well and should be good going into winter if they make the most of the nicer October weather.  I've been noticing a small amount of bearding on this hive during the day.  My thoughts are they are trying defend hive or regulate the hive temperature.

Bearding around the entrance.

The queen is back in the swing of things and had laid out a solid pattern over several frames.  Not the full frames she was doing two months ago, but hopefully enough to pull this hive through winter.

The queen seems to have been accepted well by her grandchildren.

Nice patch of brood surrounded by bee bread and several types of pollen.

Nuc 2 - Architects
This hive is a daughter of the Engineer hive so the name Architects seems fitting for them.  These girls have built up and are still taking syrup.  They inherented several honey frames from the Engineer hive.

They are taking syrup and have good activity.

Librarian Daughter Nuc
They are taking syrup.  Two frames with nice solid patches of brood.  This queen might work out after all and no more signs of them trying to make queen cells.  My winter concern for them is they are still a small hive and they really need to make the most of whatever nice weather is left for the year to build up.  They got an extra frame of honey from the Engineer hive.

Icon Daughter Nuc
They seems to have accepted their new queen and there are no signs of queen cells.  The queen has kicked up her laying and has fairly large patches of brood over a couple frames.  There are a lot of bees in here, but I don't know how many are old foragers and how many are winter bees.

Nuc 3 - Gluttons
These girls are a daughter of the Geeks, and they continuously suck down the syrup but never seem to have much of a growth spurt so I'm guessing they are quick to substitute syrup for good forage and the Gluttons seems like a fitting name for them.   They should be in good shape for winter as they have been sucking down the syrup.  They got an extra frame of honey from the Engineer hive.

Engineer Hive
Sad news, the queen was gone and there was a handful of bees and a couple cells with larvae showing signs of DWV.  Broke up the remaining honey frames for other hives.  They stopped taking food weeks ago and I noticed a big cutback on brood, but I took it to be a sign she was shutting down early for winter when really DWV was taking it's toll on the hive.

Northgate Swarm - Rebels
These girls probably have some Russian genetics and raise a lot of brood and have good stores.  They are a little feisty too which is why I'm calling this hive the Rebels.  There is a lot of uncapped honey in this hive and I'm not surprised they really aren't doing much with the syrup all the way at the back.  They have several frames of solid brood coming and are building back up quickly.  They don't store much surplus pollen which could be an issue in Spring.  I've read that Russian brood up/down based on available pollen so watching the flowers should be a good indicator of what they will be doing.

They took about a half gallon this last week.

There are a lot of bees in this hive now.  No new comb this week and only took about half the syrup from the week before.  They have built up amazingly well this summer and have packed the frames with stores for Spring.

We seem to be loosing daylight hours pretty quickly now and the bees aren't as active at the start/ends of the day, but still have good mid-day activity.

Here's a worker taking advantage of the last hours of light to bring back a little more pollen.

Back to the bees.

- Jeff

No comments:

Post a Comment