Heartbeat rate modulation mediated by the ventral nerve cord in the honey bee, Apis mellifera

Using impedance conversion as a recording technique, heartbeat patterns were established for intact adult honey bee workers during rest and during nectar feeding and locomotion, activities that both result in accelerating heartbeat. Heartbeat patterns were then described separately for bees in which assumed neural regulation was disrupted (the ventral nerve cord was transected), and for bees in which assumed neurohormonal regulation was disrupted (blood circulation to the abdomen was blocked). Heartbeat patterns from these latter two groups were compared with the baseline data from the former three groups. Results showed that normal modulatory patterns occurring during feeding and locomotion persisted when the neurohormonal pathway was disrupted, but the same modulation was absent when the neural pathway was disrupted. These results offer clear support for the conclusion that neural mechanisms provide a primary form of regulation of heartbeat in the honey bee.