Welcome! This blog is being created by students in the courses Population Ecology and Biological Diversity at the University of Oregon. It is one component of their work, and for each course will unfold throughout the term. +Jessica Green & Ann Womack
Monday, June 10, 2013
The Importance of Saving Our Pollinators
by Keir Staple, June10, 2013
Humans have become fundamentally dependent on European Honeybees and their pollination services. It is important to realize that bees are the predominant pollinators across the world, and that pollinators account for services provided to 35% of all global crops (Klein et al.) and 60-80% of all wild plants. These pollinators assist many plant species during reproduction by spreading their male gametes over wide ranges. This biological process not only supports the majority of the direct calories consumed by humans, but it also helps pollinate many of the crops that feed the livestock, which provide many of the other calories we consume. Unfortunately for both humans and global plant species, as well as all of the other species and intricate systems that directly or indirectly benefit from pollination services, bee populations around the world have dramatically declined over the past decade— specifically Apis mellifera, or the common European honeybee (Figure 1). In some cases, beekeepers reported anywhere from 50% to 90% of colony losses (Cox-Foster et al.). The reported symptoms of these losses were the lack of adult bees or dead bodies around the hive, but the remaining presence of the queen, the brood (infant bees), and honey.
So what’s causing all of this? There seems to be a general consensus in the scientific community that there isn’t just one factor that affects colonies the most, but rather a combination of many different stresses that lead to major colony losses. A number of factors are believed to be at play, but particularly a parasitic microsporidium known as Nosema ceranae (Higes et al.), a few parasitic mites (Figure 2) that spread pathogens into the bees’ airways (vanEngelsdorp et al. 2009), a paralyzing virus called Israeli Acute Paralysis Virus (Cox-Foster et al.), and disturbances in habitat and floral/nectar diversity (Potts et al.). Nosema ceranae, which previously occupied Apis cerana (Asiatic honeybee), colonized Apis mellifera and has since been associated with the collapse of honeybees. Some recent research has lead some to believe that when N. ceranae and Invertebrate Iridescent Virus (IIV6) are found working together in colonies, there is an incredibly high chance of collapse (Armstrong). However, when acting alone, these two do not provide the same results. Another study showed that honeybees infected by Israeli Acute Paralysis Virus (IAPV) in Australia did not lead to colony collapse, but colonies in the U.S. that have been infected by IAPV are showing major collapse because they have been simultaneously infected with the parasitic Varroa destructor mite (Genersch and Aubert).
On top of all of this, bees have experienced a lot of stress from the increased pressure to support our growing agricultural industry with a high exposure to chemicals, increased colony transportation, and a lack of the proper nutritional diversity in our monoculture system. All of these factors may contribute to a weaker immune system that increases the likelihood that a colony will experience CCD (vanEngelsdorp et al. 2008). To thrive, bees require a more diverse selection of pollen to feed their colonies. When exposed to only a monoculture diet, it is believed that bees may not be getting the proper amino acids they need, which may contribute to weaker immunity (Alaux et al.). It is easy to compare this problem to the human body. If you fed on only one type of food, your body would become weaker and more susceptible to illnesses. On the other hand, when you have a diverse diet you are providing your body the nutrition it needs to function properly and fight off certain pathogens.
Much of our diet’s diversity is reliant on honeybee pollination. Without these bees, we would not have access to many of the nuts, fruits, and vegetables that we have become so accustomed to eating. For example, almond production in California is entirely reliant on honeybee pollination services. For the industry to operate, they need 1.4 million honeybee colonies, which is about 60% of all commercially managed colonies in the country (http://www.ars.usda.gov/News/docs.htm?docid=15572). In total, honeybees support about $15 billion in annual agricultural production. With decreased colonies, production may become more expensive and these costs will be pushed on to consumers. This number only accounts for crop values and does not account for the value we receive from the pollination of other plant communities, and the indirect benefits that stem from there. Without these pollinators, we may lose a good portion of this lucrative industry, diet diversity, and global ecosystem diversity.
You may ask, what can be done? Well, there is some research happening in the field of agroforestry. This field combines plant community management with agricultural practices. One technique is to preserve habitats along the margins of agricultural plots to provide bees resources and a place to nest. Another technique is the use of ruderal plant species (or colonizing plant species) within the actual agricultural plots themselves. The belief is that if a diverse array of ruderal species are planted among the crops, and that the chosen species won’t outcompete the crops, then it will increase pollinator diversity and productivity (Carvalheiro et al.). In situations where this is not possible, it may be important for beekeepers to provide alternative food sources to their colonies to keep them healthy. The combination of marginal habitat and plant diversity may help increase crop productivity and decrease the pressure to expand land-use.
Figure 4. Flowers planted between rows of rice crops
Urban residents can become involved in the issue as well. Many people are taking up new hobbies and passions such as urban agriculture, green roofing, and urban beekeeping. These urban movements are progressing slowly, most likely due to a popular fear of bees as well as a the need to be creative with limited space. However, increased education will help people realize that bringing the countryside into our urban environments will help provide more habitat for bees and assist with local food and floral production. There are innovative ways of providing bee habitats around the home without having to constantly be in direct contact with them. One option is to place an artificial hive on the roof, a practice being sought in many cities such as New York and Chicago (Rueb). The TED Talk below, given by Noah Wilson-Rich, addresses the issue of declining bee populations and how integrating urban beekeeping and other remedies into our communities can help the bees and improve our lives.
With all of this information, it may seem that the future health of bees, ecosystems, and our own species may be at risk. However, there is still hope to be had. As we are increasing our knowledge of bee species and the different factors that affect colony health, we are learning more about how human practices can have great impacts on the world around us. What else is new! Thus, it will be important to look ahead and consider new agricultural practices, bee management techniques, and land-use if we want to save these pollinators that allow us to thrive. Fortunately, people are noticing the issue and taking action. I will leave you with a trailer for Queen of the Sun, a documentary meant to inspire people to engage with this issue and participate in bee stewardship.
Agricultural Research Service. "Honey Bees and Colony Collapse Disorder." ARS : Honey Bees and Colony Collapse Disorder. United States Department of Agriculture, n.d. Web. 29 May 2013.
Alaux C., Ducloz F., Crauser D. and Y. Le Conte. “Diet effects on honeybee immunocompetence.” Biology Letters 6.4 (2010): 562-565.
Armstrong, Drew. "Bee-Killing Disease May Be Combination Attack, Researchers Say." Web log post. Bloomberg. N.p., 6 Oct. 2010. Web. 29 May 2013.
Carvalheiro, Luisa Gigante, Ruan Veldtman, Awraris Getachew Shenkute, Gebreamlak Bezabih Tesfay, Christian Walter, Werner Pirk, John Sydney Donaldson, and Susan Wendy Nicolson. “Natural and within-farmland biodiversity enhances crop productivity.” Ecology Letters 14 (2011): 251-259.
Cox-Foster, Diana L., et al. “A Metagenomic Survey of Microbes in Honey Bee Colony Collapse Disorder.” Science 318.283 (October 2007): 283-287.
Genersch, Elke, and Michel Aubert. "Emerging and Re-emerging Viruses of the Honey Bee (Apis Mellifera L.)." National Center for Biotechnology Information. U.S. National Library of Medicine, 29 Apr. 2010. Web. 28 May 2013.
Higes, Mariano, Raquel Martin-Hernandez, Cristina Botias, Encarna Garrido Bailon, Amelia V. Gonzalez-Porto, Laura Barrios, M. Jesus del Nozal, Jose L. Bernal, Juan J. Jimenez, Pilar Garcia Palencia and Aranzazu Meana (2008): “How natural infection by Nosema ceranaecauses honeybee colony collapse.” Environmental Microbiology, 10.10 (2008): 2659-2669.
Potts, Simon G., Betsy Vulliamy, Amots Dafni, Gidi Ne'eman and Pat Willmer. “Linking Bees and Flowers: How Do Floral Communities Structure Pollinator Communities?” Ecology,84.10 (Oct., 2003): 2628-2642.
Rueb, Emily S. "The Colonies Expand." The New York Times. NY Times, 25 May 2012. Web. 10 June 2013.
vanEngelsdorp, Dennis, Jerry Hayes Jr. Robyn M. Underwood, and Jeffery Pettis. “A Survey of Honey Bee Colony Losses in the U.S., Fall 2007 to Spring 2008.” PLoS ONE 3, e4071 (2008).
vanEngelsdorp, Dennis, J.D. Evans, C. Saegerman, C. Mullin, E. Haubruge, B.K. Nguyen, M. Frazier, J. Frazier, D. Cox-Foster, Y. Chen, R. Underwood, D.R. Tarpy, and J.S. Pettis. “Colony Collapse Disorder: A Descriptive Study.” PLoS ONE 4.8 (August 2009): 1-17.