Heat and carbon dioxide generated by honeybees jointly act to kill hornets
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We have found that giant hornets (Vespa mandarinia japonica) are killed in less than 10 min when they are trapped in a bee ball created by the Japanese honeybees Apis cerana japonica, but their death cannot be solely accounted for by the elevated temperature in the bee ball. In controlled experiments, hornets can survive for 10 min at the temperature up to 47°C, whereas the temperature inside the bee balls does not rise higher than 45.9°C. We have found here that the CO2 concentration inside the bee ball also reaches a maximum (3.6 ± 0.2%) in the initial 0–5 min phase after bee ball formation. The lethal temperature of the hornet (45–46°C) under conditions of CO2 concentration (3.7 ± 0.44%) produced using human expiratory air is almost the same as that in the bee ball. The lethal temperature of the honeybee is 50–51°C under the same air conditions. We concluded that CO2 produced inside the bee ball by honeybees is a major factor together with the temperature involved in defense against giant hornets.
KeywordsJapanese honeybee Apis cerana japonica Bee ball Giant hornet Vespa mandarinia japonica
We are grateful to professor Kuwahara of Kyoto Gakuen University and Drs. Nakahari, Asai and Okazaki of Osaka Medical College, who made useful suggestions for the writing of this paper.
- Abrol DP (2006) Defensive behaviour of Apis cerana F. against predatory wasps. J Apicul Science 50(2):39–46Google Scholar
- Matsuura M (2003) Biology and control of social wasps and bees in urban environments 3. Honeybee Sci 24(4):193–205Google Scholar
- Schmidt-Nielsen K (1997) Animal physiology, chapter 6, 5th edn. Cambridge University Press, CambridgeGoogle Scholar
- Sugahara M (2000) Feral colonies of Japanese honeybee, Apis cerana japonica and their life history 2. Natural nests and swarming. Honeybee Sci 21(1):35–39Google Scholar
- Sugahara M, Kondou K (2005) Apis cerana japonica also makes a bee ball against Promachus yesonicus on the open nest. HANAABU 20:87–88Google Scholar
- Wigglesworth VB (1972) The principles of insect physiology, chapter 14, 7th edn. Chapman and Hall, LondonGoogle Scholar