Sibling Rivalry
Honey bees release a deadly odour to cut short their sisters' lifespan—and all for food. Bees live on body reserves of proteins and lipids called vitellogenin which also helps them tide over unfavourable conditions like shortage of food during winter. Worker bees have large reserves in their body because this is the food that is fed to young larvae; the lifespan of worker bees is about 3-6 weeks in summers and 20 weeks in winters. Scientists found that the brood releases a foul-smelling pheromone which the worker bees respond to by quickly transporting the stored fat via blood to the mouth where they are converted into a jelly, the brood feed. This cuts down the workers' lifespan even further and sometimes entire colonies collapse within 200 days. Scientists are wondering if this could be a reason for the notorious colony collpase disorder.
Source
Down to Earth, January 2010