A study explores viral manipulation of honey bee behavior to enhance transmission.
The use of honey bees for pollination has intensified in recent decades, leading to unnaturally high colony densities and coinciding with increased risk of exposure to pathogens.
Adam Dolezal and colleagues examined whether infection with Israeli acute paralysis virus (IAPV) alters honey bee social behavior in ways that influence virus spread.
Automated monitoring of colonies revealed that IAPV-infected bees engaged in fewer social contacts with colony mates than did controls, potentially preventing viral transmission within the colony.
Laboratory studies suggested that the change is part of a generalized response to viral infection.
However, IAPV-infected bees elicited less aggression in bees from other colonies and were more likely to be accepted into foreign colonies, compared with controls, thereby facilitating viral transmission between colonies.
The reduction in aggression was accompanied by changes in the levels of cuticular hydrocarbons (CHCs)—chemicals used by bees to distinguish colony members from intruders.
Both the reduced aggression from foreign bees and the CHC changes were specific to IAPV infection. The results suggest that IAPV manipulates host social behavior to enhance transmission.
The high colony densities found in modern apiculture might facilitate the evolution of similar strategies in honey bee pathogens, according to the authors.