Scientists have long been puzzled as to why the queen honeybee is able to live 10 times longer than her genetically identical sisters. In most species, having many offspring would negatively effect longevity. Paradoxically, the incredibly fertile Queen Bee seems to have a marked advantage over her sterile sisters.
“Many times the way organisms achieve longevity is via a tradeoff with reproduction,” said entomology professor Gene Robinson who helped conduct the study, “In general, life forms that postpone reproduction until later in life live longer. But the queen bee has her cake and eats it too. She’s an egg-laying machine. She lays 2,000 eggs a day and yet lives 10 times longer than individuals that stem from the same genome and yet do not reproduce.”
So what’s her secret? A study from the University of Illinois has discovered the molecular mechanisms that may help explain the divergence. Vitellogenin (Vg), is a yolk protein important to reproduction and has also been found to contribute to longevity in worker bees.
Former studies have shown that manipulating fat body cells in the head of the fruit fly has an influence on longevity. Because Vg is synthesized in fat body cells in honeybees, the team decided to look at Vg expression in the head, thorax and abdomen. That’s when the researchers made their interesting discovery. Expression of Vg was high in the abdomen in the young queen and declined over time, but increased with age in the head and thorax. Old queens showed much higher Vg expression than young queens.
Vg in worker bee’s heads was low compared with queens. Vg appears to prevent oxidative stress in honeybees by scavenging free radicals that can lead to aging or illness. This accounts for why queens are more resistant to oxidative stress than workers, bringing new meaning to the cliché, “It’s all in your head.” Scientists are interested in knowing if any of these findings could influence our understanding of human longevity.
“There are implications here (for other species) in the sense that here is an organism that is reproductively active and long-lived,” said Robinson, who is affiliated with the Institute for Genomic Biology. “And we see novel and conserved factors that are part of a large regulatory network. The queen has her cake and eats it too. And humans want to know how that works.”
Posted by Rebecca Sato
*adapted from a news release from the University of Illinois at Urbana-Champaign