USU research points to bee extinction
Several bumblebee species are on the decline, according to a study conducted over the last few years by two U.S. Department of Agriculture researchers, USU adjunct professors and one USU graduate student. The research, which began in 2007, studied eight different species of bumblebee.
“It turns out that at least four of the species in our study have declined significantly, the other four are okay,” said Jamie Strange, a USDA-ARS research entomologist and adjunct assistant professor in USU’s biology department. “The decline has happened rapidly in the last two decades.”
Jonathon Koch, USU graduate student studying entomology, said one species watched declined by 96 percent.
Strange’s USDA-ARS colleague, and research entomologist, Terry Griswold, said, “You expect some year-to-year variation in birds and it is the same with bumblebees. The question is, is this a local phenomenon, or are we looking at a broad trend of declines?”
The study began after Strange and Griswold noticed that bee researchers, growers and produce farmers were mentioning a decrease in the amount of particular bumblebee species.
Koch said: “The reason why we studied these species is because they were historically abundant. People are saying they aren’t finding bumbles in studies, so in 2007 we started this study to test general patterns of these species that were at concern.”
The methodologies in the study included collecting historic data on bees from more than 40 museums throughout the country, as well as sampling 386 locations.
Strange said, “To get a view, we went back through museum collections of bees, such as the Smithsonian, to see historic numbers of bees in relation to each other. We looked to see if a decline in each species was common or rare.”
After all the historical data was gathered, the researchers personally gathered live data and then compared the two.
“We compiled all the museum information and did a lot of personal data gathering,” Koch said. “We sampled 386 different locations. We sampled in the western half of the United States, while the University of Illinois sampled the Eastern United States. Then we compared current surveys with the historical data and that is how we compare relative abundance.”
Strange said the research took three years to complete because along with collecting museum data, they traveled the country and personally sampled places such as Glacier National Park, Flagstaff, Ariz., central New Mexico, a national monument in California, and some backyards.
Griswold said the reasons for the decline are unknown and could be a result of pathogens, differences in land use or changes in climate.
Strange explained the reason bees are important is because they are the main pollinators of agriculture. Bumblebees are especially good at pollinating crops such as tomatoes, blueberries and peppers, while honey bees actually do not pollinate tomatoes. Because of this, tomato growers must buy bumblebees to pollinate their crops, even though they are more expensive than honeybees.
Griswold said another goal in their study was to find and maintain specialty pollinators and additional pollinators so agricultural growers can select bees to pollinate their crops based on either how effective they are, or how economic they are.
“Right now a hive of bumble bees cost around $200 for 250 bumble bees, where as you can get 10,000 honey bees for $125,” Strange said. “Most vegetable growers buy honey bees to pollinate their crops for economic reasons unless they grow a plant that honey bees do not pollinate, like tomatoes. Apple growers would be interested in purchasing a bee that flies at the lower temperatures that often occur during apple bloom.
Strange said the effectiveness in vegetable production has not gone down since the decline in specific species of bumble bees, but there is still a long-term concern.
“The thing that should be concerning us is when you lose 10 percent of bumble bee species, “you set yourself up so that every future stress on species will be felt more,” Strange said. “The current problem is that we are losing bumblebee diversity, but we may see a loss in all bees.”
Koch explained the impact of the decline in species with an analogy of a plane losing its rivets. He said that losing one or two rivets on a plane will not make it crash, but if you lose 30, the integrity of the plane changes. The same is true for bees. Only so many species can be lost before it affects all bees.
One remedy the entomologists are looking towards includes raising the endangered bumblebees, which commercial producers have stopped raising, and sending them to producers. Strange is working on doing this with students in a lab at USU.
According to the research team, the community can also do a lot to help. They can plant “pollinator friendly” gardens, refrain from spraying flowers in the middle of the day when bees are visiting flowers, and try not to destroy bee nests unless they are a danger to humans.
– kayla.barclay@aggiemail.usu.edu