Detection of neural activity in the brains of Japanese honeybee workers during the formation of a "hot defensive bee ball"

• Published in: PloS one Vol. 7; no. 3; p. e32902
• Main Authors: Ugajin, Atsushi, Kiya, Taketoshi, Kunieda, Takekazu, Ono, Masato, Yoshida, Tadaharu, Kubo, Takeo
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 14.03.2012; Public Library of Science (PLoS)
• Subjects: Agriculture; Animal behavior; Animals; Anti-predator behavior; Apidae; Apis cerana; Apis cerana japonica; Apis mellifera; Apis mellifera ligustica; Apoidea; Bees; Bees - drug effects; Bees - genetics; Bees - physiology; Biology; Brain; Brain - drug effects; Brain - pathology; Brain - physiology; Brain mapping; Colonies; Defensive behavior; Drosophila; European honeybee; Foraging behavior; Gene Expression Regulation - drug effects; Genes; Genes, Immediate-Early - genetics; Heat; Heat shock proteins; Hierarchy, Social; Homology; Hymenoptera; Immediate-early proteins; Insect Proteins - genetics; Insect Proteins - metabolism; Insects; Japan; Mushroom bodies; Nervous system; Neurons; Optic lobe; Pentanols - pharmacology; Pheromones - pharmacology; Predators; Science; Seizures - genetics; Sequence Homology, Amino Acid; Social Behavior; Survival; Temperature; Thermal stimuli; Vespa; Vespa mandarinia japonica; Vespidae; Veterinary Science; Wasps; Wasps - drug effects; Wasps - physiology; Workers; Workers (insect caste); Japan
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0032902

Anti-predator behaviors are essential to survival for most animals. The neural bases of such behaviors, however, remain largely unknown. Although honeybees commonly use their stingers to counterattack predators, the Japanese honeybee (Apis cerana japonica) uses a different strategy to fight against the giant hornet (Vespa mandarinia japonica). Instead of stinging the hornet, Japanese honeybees form a "hot defensive bee ball" by surrounding the hornet en masse, killing it with heat. The European honeybee (A. mellifera ligustica), on the other hand, does not exhibit this behavior, and their colonies are often destroyed by a hornet attack. In the present study, we attempted to analyze the neural basis of this behavior by mapping the active brain regions of Japanese honeybee workers during the formation of a hot defensive bee ball. First, we identified an A. cerana homolog (Acks = Apis cerana kakusei) of kakusei, an immediate early gene that we previously identified from A. mellifera, and showed that Acks has characteristics similar to kakusei and can be used to visualize active brain regions in A. cerana. Using Acks as a neural activity marker, we demonstrated that neural activity in the mushroom bodies, especially in Class II Kenyon cells, one subtype of mushroom body intrinsic neurons, and a restricted area between the dorsal lobes and the optic lobes was increased in the brains of Japanese honeybee workers involved in the formation of a hot defensive bee ball. In addition, workers exposed to 46°C heat also exhibited Acks expression patterns similar to those observed in the brains of workers involved in the formation of a hot defensive bee ball, suggesting that the neural activity observed in the brains of workers involved in the hot defensive bee ball mainly reflects thermal stimuli processing.