The two pieces of evidence that best support the inference that honeybees—not bumblebees—are responsible for infecting the studied flowers are:
- All the infected flowers researchers picked and tested were close to apiaries.
- All of the honeybees researchers collected were infected with both viruses.
These pieces of evidence suggest a strong link between honeybees and the infection of the flowers, while also indicating that the presence of infected honeybees in close proximity to the flowers is likely a contributing factor to the observed infections.