By Coco McPherson, Rolling Stone
30 August 15
Expert Scott Black explains why bees are the canaries in the ecological coal mine
t's no secret that bees are in trouble.
What's causing bee populations to plummet – neonicotinoid pesticides,
mites, stress – remains hotly contested, despite a growing body of
scientific evidence that neonics are part of the problem. But last week,
the results of a landmark British study tracking neonic use for over a decade showed a direct correlation between a class of these pesticides and bee colony losses.
"This is important," says ecologist Scott Black,
"because it's the large-scale field study showing the same thing that
everybody's suspected."
Rolling Stone recently asked Black, executive
director of the Xerces Society for Invertebrate Conservation, to
explain the significance of the study, why bees are so unique and why
scientists consider invertebrates to be the canaries in the ecological
coal mine.
Bees and their role in food production are
constantly in the news. But many people can't really visualize what
exactly bees do. To start, can you explain pollination?
Pollination is the transfer of pollen from the male
part of the plant to the female part of the plant. There's both animal
pollination and wind pollination. The largest animal pollinator we know
of is the lemur in Madagascar. Hummingbirds and bats pollinate, but the
vast majority of pollinators out there are insects. The main pollinators
of our crops are bees, and not just honeybees. People often say,
"One-third of all our food comes from honeybees." That's not accurate.
It comes from bees.
Wild bees and honeybees.
Honeybees are vitally important, but wild bees,
especially for certain crops — apples, lots of our berries – are really,
really important. We need that pollen to get from one flower to the
next flower, and from the male part to the female part. And bees are
really good at this because unlike all other animals that are visiting
just to eat the pollen and/or nectar, bees actually collect it because
they're feeding it to their young.
They're one of the only animals out
there that actually collect the pollen rather than just feeding on
pollen, so they visit many more flowers. They've evolved to collect
pollen. Once they find a flower that's producing a lot of pollen and/or
nectar, they cue in on that type of flower. Bees are very efficient and
very good at pollination. Humans just can't do this on any scale. For
one thing, it's very expensive. You don't have to pay bees. You have
hundreds of millions of workers out there who are doing this for free.
If we want the most nutritious foods, bee pollination of our crops is
really the only way forward.
When a hive is brought to a field or a farm and the bees are released, what's happening?
The goal of the hive is to produce more bees, more
young. These bees aren't saying, "Oh, we're here to help the humans."
Young bees need pollen and nectar to grow up.
Bees are brought in a
hive, they fly out and they start to look for sources of both pollen and
nectar – they want both. When they find those sources, they can
communicate with the other bees in the hive where those best sources
are. It's fascinating. They go out and collect pollen and nectar until
they can't collect any more, and they bring it back to the hive. They
store it and also feed it to the young, then go back. They do this all
day. They're really efficient at figuring out where the food is, and
then collecting it and bringing it back.
So the transfer from the male part of the plant to the female part happens by, what, beautiful coincidence as bees are feeding?
Coincidence is maybe the wrong word. Flowers and bees
have evolved together.
These flowers are advertising themselves. They're
getting these animals to stop to either sip nectar or to actually
collect pollen. Either way, they're getting pollen on them. Then the
bees fly off, and the next flower is also advertising. The bee stops
there, and some pollen always comes off. It's an incredible co-evolution
of these flowers and these animals that really draws these animals in
to help the flower. Flowers are advertising and providing the reward
that keeps the bees coming back. It's not by accident; what's really
cool about it is that it's by design.
Bees have been harnessed – like mules to a cart – to do this work for us.
The thing I find interesting is that honeybees were
not originally managed to do pollination, but for a sugar source. Europe
didn't have sugarcane, of course, so honey was used to make mead, to
sweeten other food sources. Crop sizes were small, there was habitat
everywhere and if you didn't have native bees, you had wild honeybees
around. That's the reason they brought honeybees to the New World. In
the early 1600s, they brought them on ships, and then moved them across
the country in wagon trains. Again, nobody thought about pollination;
pollination just happened. It was the 1930s and Forties, with the advent
of giant monocultures and the use of synthetic insecticides, that
people started to see that they weren't getting the pollination they
used to. That's when we started moving honeybees for pollination, that's
when the industry came into its own. We can box these animals up and
take them on a truck to where they're needed.
You don't think this is sustainable.
We're using one animal to try to pollinate a
disproportionate amount of our food. And although I think they're going
to be important for a long, long time, I also think we underutilize the
native bees that are often out there. To really have sustainable
agriculture and a sustainable system of feeding people, we should not
rely on just one animal to pollinate most of our crops.
The British field study shows a link between
neonicotinoid pesticide use and honeybee colony loss. There's a lot of
research out there – why is this being heralded as a "first"?
They're not saying it's the first time [they've proven
a connection]; they're saying it's the first time in a field situation.
We've had many studies that show that if exposed, these chemicals are
highly toxic and will kill bees. We have lots of studies that show even
at small amounts, these chemicals will change the behavior of bees,
they'll have fewer babies, and they won't be able to forage as well. And
we have tons of evidence that these things are found everywhere – in
urban and agricultural situations. You put that together and you can
say, "OK, these are highly toxic." We know bees are contacting them, you
can connect the dots, but this is the large-scale field study showing
the same thing that everybody's suspected.
Why is that important?
It's important because chemical companies have said
that that we don't have studies that show this in the field. We can have
all this data, and yes you can say this is impacting bees, but we
haven't shown this in a long-term field study. So this is an important
one.
The U.S. Geological Survey just published a report about neonicotinoids being in streams all over the country.
The USGS study simply says that these chemicals are
found in half the streams we've sampled. The USGS is a scientific body
and they're very careful, but I think it does add to a huge body of
evidence – for instance, the International Union for Conservation of
Nature, with their meta-analysis of 800 studies showing that these
chemicals are really a problem for pollinators and other beneficial
insects, and they're a huge problem for aquatic insects. Neonics are
easily transported from soil into water, and they're very toxic to
aquatic organisms that make up the base of the food chain for fish and
for the birds who eat the insects. What's really interesting is that
there are almost no studies coming out that are saying these chemicals
are safe.
What's about the chemical companies?
As each new study says this is continuing to be a
problem, it does get harder for the chemical companies to say that this
isn't a problem. They'll always point to the uncertainties inherent in
science; they did this with lead in paint, tobacco, and climate change.
They sow seeds of doubt even though they do not have the evidence to
support their conclusions.
Are invertebrates the canaries in the coal mine in terms of ecosystem health?
Yes, they certainly are. They're really important for
understanding the health of our ecosystems because they can be readily
monitored and they're the base of the food chain. If you like to eat
salmon, you can thank small flies in the stream where these salmon were
born. If you like to eat nutritious fruits and vegetables, you can thank
bees. If you like to watch songbirds you can thank the insects that
they eat – if birds are in your yard, it's because there are insects
they feed their young. These things are super important and really are
the harbinger of whether you're doing well or poorly. If you're seeing
fewer insects – bees or aquatic insects – you know it's affecting the
birds and the fish and onward up to the people.
