Honey Bee, Copulation Flight of Queen and Drone.

A male honeybee mates with a queen in mid-air. The semen that a male transfers to a female degrades her vision — and with it her ability to mate with other males. Credit: Otto Hahn/SPL

Animal behaviour

Sex clouds queen bees’ vision

Semen that impairs a female’s eyesight is one weapon in the sexual arms race between male honeybees and queens.

After insemination, honeybee queens lose some of their vision — and often lose their way.

Queen honeybees (Apis mellifera) embark on mating flights over the course of several days, often collecting sperm from multiple males to boost their hive’s genetic diversity. Evolutionary theory predicts that a male should attempt to prevent queens from mating with other males. In keeping with that prediction, research has suggested that natural insemination alters the activity of vision-related genes in female bees.

To determine the consequences of such changes, Joanito Liberti at the University of Copenhagen and his colleagues artificially inseminated queen bees and found that they became less responsive to light and were more likely to get lost on mating flights than were queens given saline.

Inseminated queens also tended to leave their hives on mating flights two days earlier than control queens. The researchers propose that this early departure was an attempt to compensate for their poor vision.