For around a decade, beekeepers have seen around one-quarter to one-third of their colonies die every year. There are many potential causes for the die-off, but most scientists agree a parasitic mite is a major factor.
Purdue entomologist Greg Hunt says if a bee were human-sized, the mite would be about the size of a balled-up fist. Other scientists say the size is more comparable to a pancake.
But now, Purdue University scientists have bred special bees that are biting back.