Scott Hoffman Black

Scott Hoffman Black

U.S.A. Humans are ecological conquerors and destroyers. In our efforts to improve our lives on Earth, we have created a new threat to ourselves—the extinction of honey bees. Below Scott Hoffman Black shares some insight on this endangered species, implications potential extinction has for the planet, and conservation efforts led not just by scientists, but by civilians too.

Scott Hoffman Black is the Executive Director of the Xerces Society for Invertebrate Conservation. Here, he speaks to ROOSTERGNN in an exclusive interview about the past, present and future of honey bees.

There are many bee populations. However, when we talk about endangered species and conservation, are we are usually referring to honey bees?

Scott Hoffman Black: There are over 25,000 species of bees in the world.  We have very little information on the conservation status of most of these species.  They range from very small, blue, black or metallic green (many people might think these are flies) to our larger bees like bumble bees.  When people think about bees, they usually either think about honey bees or bumble bees.  Honey bees are used to provide pollination service around the world and numbers of honey bee hives have dropped in many places.  There are several different types of honey bees in the world, but most people use the European honey bee for pollination.  Honey bees are not native to North or South America.

There are over 250 species of bumble bees in the world. The Xerces Society is working with the IUCN bumble bee specialist group to evaluate the conservation status of the worlds bumble bees.

Significant conservation attention has been given to bumblebees in the UK and in North America. In the US, we know that over 25% of all bumble bees may be faced with extinction in the coming years…It is hard to know if declines are increasing as populations are not tracked every year, but we do know that many are imperiled.

What is the greatest threat to the bumble bee population? Can you single one out?

You cannot single out any one greatest threat.  There are a number of threats facing bumble bees, all of which may be leading to the decline of these species. The major threats to bumble bees include: spread of pests and diseases through commercial bumble bee rearing or other methods, habitat destruction or alteration, pesticides, invasive species, low genetic diversity and climate change.

There is a lot of buzz about pesticides and their effects on the bumble bee population. Can you tell us how exactly they impact bees? Are they the main culprit in the decline?

Pesticides (specifically insecticides) are likely an important factor in bumble bee declines. Insecticides are designed to kill insects, and when used where bumble bees are present, they can be devastating.  In Oregon, U.S.A., over 50,000 bumble bees were killed because insecticides were used when high numbers of bumble bees were visiting Linden trees.

Across Europe, Canada and the United States, a possible link to bee die-offs has made a newer class of insecticides a particular concern: Neonicotinoids.

Imidacloprid, clothianidin, dinotefuran and thiamethoxam (four of the most widely used neonicotinoids) are highly toxic to honey bees and bumble bees. Some of the breakdown products are just as toxic. Even if bees are not killed outright, sublethal levels of neonicotinoids can damage the ability of honey bees to fly and navigate and learn new tasks, which can impair their foraging abilities. There is also emerging evidence that neonicotinoids affect the honey bee queen’s ability to lay eggs.  All of these issues impact hive health. Bumble bees exposed to imidacloprid at levels found in crops produced 85% fewer new queens and had significantly reduced colony growth rates. Loss of queens will decrease future bumble bee populations.

We know that when pollinators or other beneficial insects are directly exposed to these chemicals there can be a negative impact. But are they being exposed through the environment? I believe the answer is yes. Here is why.

These products have a systemic mode of action: This means they translocate into every part of the plant including nectar and pollen.  They can be persistent for long periods in plants and soil. Neonicotinoids can persist in soil for months or years after a single application. Also, untreated plants may absorb chemical residues in the soil from the previous year. Measurable amounts of residues were found in woody plants up to six years after a single application. Neonicotinoids are now the most widely used class of chemicals in the world.

In terms of the food chain, how critical are bumble bees?

Bumble bees and other pollinators are vitally important for the food chain.  Pollinators are critical components of our environment and essential to our food security. Insects – and primarily bees – provide the indispensable service of pollination to more than 85% of flowering plants contributing to 35% of global food production. Many vitamins and other nutrients essential to human nutrition are found primarily in plants that require insect pollination, so the loss of pollinators may pose challenges to human nutrition. In Europe, declines in pollinators have been associated with a parallel decline in insect pollinated plants.

Bumble bees are among the most iconic and well understood group of native pollinators in North America. They are generalist pollinators that play a valuable role in the reproduction of a wide variety of plants, including human food crops such as tomato, squash, melon, blueberry, pepper, cranberry and clover, and numerous wildflowers.

How common is colony collapse disorder? Can you tell us about it in more detail?

Colony collapse disorder is a phenomenon in which worker bees from European honey bee colonies abruptly disappear. They leave the queen and brood (babies), which all subsequently die. The syndrome was named colony collapse disorder in late 2006 in conjunction with a drastic rise in the number of disappearances of colonies in North America. This is a serious issue in that some beekeepers lose a large percentage of bees each year. Colony Collapse Disorder has afflicted millions of honey bee hives around the world.  It has been devastating for the honey bee industry in the US.

Theoretically, if bumble bees were to die out, couldn’t another species of bees, i.e. honey bees, compensate in terms of pollination?

If any one species of pollinators dies out, we can expect another to take its place.  These systems are highly redundant.  That said there is evidence from Europe that declines in pollinators have been associated with a parallel decline in insect pollinated plants. I equate it to the parts of an airplane.  You might be able to fly if one bolt is loose or missing.  You might make it if two or three bolts are loose or missing.  But at some point the plane will crash.  The same can be said about these ecosystems.  Losing all (or even a large portion of bumble bees) would likely make the system crash.

In efforts to save bees and prevent extermination, there are been efforts to move them outside of areas, especially cities. Is this a fair compromise between humans and the environment?

We cannot move these species to protect them.  We have to deal with the critical issues affecting their survival.  Habitat loss, diseases, pesticides and other issues need to be addresses.  We need pesticide free high quality habitat patches spread across the landscape if we hope to stem the decline.

One way citizens can help conservation efforts is by identifying and tracking bees for scientists. How is this helpful?

Citizen scientists can be enormously helpful in our efforts.  These efforts can help us understand where these species are and which ones are in decline.  For highly imperiled species we can get specific locational information so that we can protect and manage habitat.  For more on bumble bee citizen science effort in the US go here.

What are other ways that citizens can help conservation efforts?

Being part of the pollinator conservation solution is simple.  Provide flowers that bees and other pollinators need and do not use insecticides.  The neat thing about pollinator conservation is that anyone can do it.  Whether you own a window box, manage a farm or have a garden there are simple steps you can take to be part of the solution. See more here.


Scott Hoffman Black is the Executive Director of the Xerces Society for Invertebrate Conservation. He also serves as the Chair of the International Union for Conservation of Nature (IUCN) Butterfly Specialist Group, Chair of the Migratory Dragonfly Partnership, Vice Chair of the Monarch Joint Venture and as Vice Chair of the IUCN Invertebrate Conservation Subcommittee. He has a Master’s of Science Degree in Ecology and has authored over 200 scientific and popular publications, co-authored two books and contributed chapters to several others. His work has also been featured in newspapers, magazines, books and on radio and television. Mr. Black has received several awards including the 2011 Colorado State University College of Agricultural Sciences Honor Alumnus Award, and the National Forest Service Wings Across Americas 2012 Butterfly Conservation Award.