Honey Bee vs Viruses. Who wins?

Honey Bee vs Viruses. Who wins?


Beekeeper question of the week I heard
that viruses are very dangerous than a big problem in apiculture today
because of a Varroa destructor but I also heard from other researchers that honey
bees can handle viruses very well. It seems a contradiction to me, can you
explain it? I think it can. it seems a contradiction but in fact I
would say it depends of the situation let me explain. I’m going to Humberto Boncristiani and this is InsideTheHive.TV the show that takes you into the world of
bees. If you’re new to the channel welcome. We like to talk about bees here
so if you enjoy bees and like to learn about them please subscribe to the
channel and also follow us on the social media. So addressing the question of my
fellow beekeeper. I’m not sure where you heard that or in which circumstances or
which context but I think I know where’s the problem. Let me address first the
second part of the question, the part that said that honey bees can handle
viruses very well and to address that I want to invite you to come with me and
to see the results of an experiment that I have done many many times in my career.
the experiment will answer a very simple question. How many viruses do we need to make a bee sick? To perform such experiment we’re gonna to put a bunch of
bees in cups, newly merged bees so they have the same age and we’re
gonna feed them with viruses in different concentrations and we’re gonna
wait from 3 to 5 days and wait to see which concentration make them sick. The
virus in this experiment is IAPV a very old friend of mine. But keep in mind that
the these numbers that I am going to show you might vary depending of the type of
virus, the strain of the virus, and the genetic of the bees. Ok let’s start. One
virus / Bee. Nope 10 viruses / Bee not yet a 100 viruses / Bee, Nope 1000 viruses
/ Bee Not yet 10,000 viruses / Bee Not even close, a 100,000
viruses per bee. NAAhhhh Okay, 1 million virus particles per bee. Nope.
10 million nope hundred million virus particles/bee Yes. That’s the number. To
make a bee sick you need with these virus with this specific strain of
viruses, you need a hundred million particles of viruses per bee to make them
sick around three to five days. What’s the message here? the message here that bees can be very tolerant to viruses. 100 million virus particles per
bee is a very significant amount of viruses that it’s very difficult to find
in nature. Only in drastic conditions we might find such concentration of
viruses. Yes it’s might occur, but it’s kind of rare. But we’re going to go back to this
subject later. Hold that thought. So now let me change
something so I can show you something interesting. Instead of feed the bees
with the viruses let’s now inject them with the same concentrations of viruses
and see the effect. Let’s start it. one virus / bee Nope, 10 viruses / bee Nope, a hundred viruses / bee no, 1,000 viruses/bee Yes,
you only need 1,000 viruses/bee to make a bee sick. If we inject it directly into
the body. Look how drastic the changes are. to cause the same amount of damage you need a hundred thousand times fewer viruses. So, what is going on here? Along evolution bees have faced viruses all the time.
Viruses are not something new that just arrived in nature recently. The bees that
we have today is the result of natural selection, meaning the bees that
we have today have specific mechanisms to deal with viruses. In the past the
main way for honeybees to get viruses infection was through the digestive
system. Bees consume nectar, bees collect things and share nectar with
other bees so the digestive system was the main inoculation road for
viruses in the past. Therefore, the bees that survived are the bees that have
something special in the digestive system to survive a virus infections. And
today we know some of those things. The digestive system is a very tough
environment for viruses. We know that the viruses have to pass through a
different pHs, they have to pass through different enzymes, they have to pass
through beneficial microorganisms, and other factors. The second level of
defense even if they pass through the digestive system and reach the cells
they need to reach to start their replication. Inside the cells bees have
developed mechanisms to defend themselves against
viruses as well. We know that these can produce antimicrobial peptides and also
they have RNA interference mechanisms to defend themselves against viruses. And even that the bees pass through the digestive system, also replicating
in the cell and escape from that and reach hemolymph and spread. Because bees are
so social and they have developed a third level of security. Bees are able to do
something just amazing. They feel they’re sick and they fly way to die alone, so
they can protect the hive. Isn’t that amazing! So in this scenario
when bees get viruses throughout the digestive system which it was the main
open door for viruses in the past we can say that they are tough against viruses
so they have plenty of defenses to deal with viruses however when the little guy
called Varroa destructor a mite that feed on the fat bodies of honey bees
they need to open wounds to get access to the fat bodies and then allow viruses to
get right in that and reach the hemopymph passing through all those
defenses just destroying all defenses that were selected through millions of
years. In one single shot Varroa destructor just make the bees defenseless against viruses. And now you can see the power of varroa destructor when
varroa destructor decided to jump from a Apis ceranae to Apis mellifera that was a
complete game changer for virus infections in honey bees. A good
comparison is to build a castle with all the defenses in the front door and then
you forget the back door open and the enemy just go through there.
Now let’s go back to that thought that I asked you guys to hold before. Do you
remember that I said that it was rare to have a situation where the bees have
that big amount of concentration of viruses so adult bees through feeding
could get sick. Well now with Varroa destructor we have the
situation inside the hive, because Varroa destructor like to feed not only in adult bees, actually they prefer larvae and pupae, which means they gonna
be there cooking a lot of viruses and die
so the adult bees is going to need to deal with those dead bodies that cannot fly
away to protect the hives anymore
the workers are gonna need to deal with that and dealing with that they’re
exposed to a gigantic amount of viruses. So even that ,the protection they had
before throughout feeding through the protection that was selected through
evolution is compromised as well because the amount of viruses that we
might have inside the hive right now is too much. So that’s it for today I hope
with this video I could clarify the contradiction a little bit. If you
enjoyed this video please hit the like button share with friends and family
consider to subscribe to the channel and I’ll see you guys in the next video.
Thanks for watching, inside the hive.TV the show about bees.

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