Honeybee colonies have been collapsing at alarming rates since 2006, and experts still aren’t completely sure why.

New research in the journal Scientific Reports suggests one possibility: Honeybee life spans today are half what they were 50 years ago.

While reviewing previous research, the authors noted that bees from the 1970s lived an average of 34 days versus around 18 days now.

Shorter lives mean less time to gather pollen and nectar, which translates to less honey for winter survival.

Using a computer model, researchers calculated the truncated lives would result in annual colony losses of 33% — a close match to the 30%-40% reported by beekeepers.

The cause remains unknown, but the authors hypothesize that breeding disease-resistant stocks may have inadvertently created shorter-lived bees, which would have less time to spread diseases. If true, it would suggest the possibility of breeding back longer-lived bees.