The nepotism chemical

Researchers of the University of Illinois in Urbana, USA, led by Gene Robinson, say nepotism among bees is governed by a brain chemical that helps them distinguish intruders from fellow hive members. The researchers injected the brains of bees with a chemical that mimics the effects of a neurotransmitter called octopamine. Bees with boosted levels of the chemical were more aggressive towards bees from other hives, but more friendly towards their own nest mates. Robinson suggests that octopamine may enhance the sense of smell among bees ( Nature , Vol 399, No 6736).