Study: Bumblebees lacking high quality habitat are heavily loaded with pathogens

Research-led, bumblebees found in low-quality landscapes are characterized by relatively few spring flowers and high-quality nesting sites, similar to bumblebees in areas with a large number of managed bee hives. The level of pathogens was high. According to Penn scientists.

The results of a study investigating how different environmental and landscape characteristics affect infectious disease epidemics and honeybee health help protect honeybee species that provide essential pollination services for natural and agricultural ecosystems. Can be used to inform management practices for doing so. The researcher said.

“The recent global decline in wild and managed honeybee populations is due to several factors,” said the lead researcher at the Penn State University of Agricultural Sciences Center for Insect Biodiversity. The author, DJ McNeill, said. “For example, widespread habitat loss and degradation led to a lack of flower and nest locations, which in turn contributed to the loss of wild bee abundance and diversity.”

He recently attributed the loss of some bees, especially between bees and bumblebees, to elevated levels of new bee pathogens, probably exacerbated by other factors that weaken the bee’s immunity or resistance. It pointed out.

“Many of the factors known to impair bee health, such as malnutrition and exposure to pesticides, can increase susceptibility to the disease,” McNeil said. “In a landscape with fewer and fewer flowering plants, bees are more likely to be deprived of nutrients, and malnutrition can reduce the immune response and increase the burden of pathogens and parasites.”

The incidence and burden of certain pathogens or parasites in bee populations is also likely to be affected by the composition of the bee community, associate professor of biology and entomology in Penn State, co-author of the study. Heather Hines, a professor, said. She explained that the incidence of viruses and parasites in wild bumblebees was higher in the presence of honeybee colonies. Bee colonies are often loaded with pathogens that are transmitted to native honeybees.

“Given all these interacting factors, the prevalence and pathogenicity of the disease can be difficult to predict in wild bee populations,” Hines said. “Our study is the first study to use data from a large geographic scale to assess the relative role of landscape features on the distribution and load of major wild bee pathogens and parasites. It is one of. “

To measure pathogen loading, researchers analyzed common eastern bumblebee specimens-Bombus impatiens, the region’s most abundant bumblebee species. The team recruited bumblebee workers from sites throughout Pennsylvania during the peak breeding of bumblebees in late June and mid-July 2018 and 2019. Includes a variety of habitat types and land use patterns.

Next, researchers explored three pathogens known to infect bees: the deformed wing virus, the black queen cell virus, and the microsporidia parasite Vairimorpha, and the expression of genes that regulate immunity. I screened. Using statistical analysis techniques, the presence and load of pathogens, flower abundance, nesting quality, pesticide load, climatic conditions, interaction with controlled bees, and several recognized landscapes Correlated with a scale stressor.

Their findings, reported in Scientific Reports, show that bumblebees collected in low-quality landscapes show the highest pathogen load, with spring flower resources and nesting availability acting as the main driving force. Suggested. The study also found a high load of bumblebee pathogens, which are more abundant in honeybee apiaries, a positive relationship between Vailimorpha load and rainfall, and geographic differences in pathogens.

According to McNeil, the results of this study highlight the need to maintain and create high-quality landscapes, such as flower and nesting resource-rich landscapes, to support healthy wild bee populations. It is said that it is. The findings also focus specifically on the value of spring flower resources. Spring flower resources are often less emphasized in pollen breeder garden plantings than in midsummer feed.

“Our results suggest that these landscape indicators may be able to predict potential risks from pathogens and parasites. This is where habitat restoration and conservation practices are practiced. It can help in deciding what to apply, “he said. “This is especially timely in light of the widespread population decline of many insect groups, especially pollen maters such as bumblebees.”

Researchers said they hope to incorporate this information into Beescape, an online tool that allows people across the United States to assess the quality of their landscapes. They encourage homeowners, growers, and conservationists in Pennsylvania to read the Pennsylvania Pollen Matter Conservation Plan. The plan includes chapters on best practices for creating bee feed and habitat in urban, agricultural and natural landscapes.