It鈥檚 not so much eternal life, more a case of instant death. Parasitic beetles that dare to invade the hive of certain stingless bees end up entombed forever in resin. 鈥淭hey鈥檙e stopped in their tracks and they dehydrate and shrivel up like a mummy,鈥� says Mark Greco, an entomologist at the Swiss in Bern who discovered the practice in a species of Australian stingless bees, Trigona carbonaria, living in the wild.
To further investigate this peculiar defence, Greco鈥檚 team planted parasitic small hive beetles, Aethina tumida, near the entrance of laboratory beehives. Guard worker bees instantly attacked the parasites, but the thick-skinned beetles had little trouble warding them off.
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Faced with such a resilient foe, a group of workers resorted to coating the beetles in a sticky mix of resin, mud and wax. From computerised tomography (CT) scans of hives flash-frozen at 5-minute intervals, Greco鈥檚 team found the mummifications take less than 10 minutes.
The beetles rarely got very far from the entrance before being mummified. The only time Greco saw the beetle invasions succeed was during a hot Australian summer, when temperatures above 40 掳C may have stressed the bee colony and prevented the resin from setting.
The behaviour may have evolved out of conventional hive-patching, in which stingless bees use a similar resin to secure loose bits of their hive. 鈥淭heir instinct is to glue something down if it鈥檚 not secure,鈥� Greco says.
Other stingless bees also make mummies out of intruders. Some tropical species even mix in acidic secretions that eat away at the beetle鈥檚 hard cuticle.
Journal reference: , DOI: 10.1007/s00114-009-0631-9
