Insulin signaling key to caste development in bees

Jul 14, 2010
Insulin signaling is key to separating those who would be queen (marked in blue) from workers. Credit: Credit: F. Wolschin and AJ Siegel

What makes a bee grow up to be a queen? Scientists have long pondered this mystery. Now, researchers in the School of Life Sciences at Arizona State University have fit a new piece into the puzzle of bee development. Their work not only adds to understanding about bees, but also adds insights into our own development and aging.

The study, which appeared in the June 30 online edition of Biology Letters, shows that a key protein in the insulin signaling pathway plays a strong role in caste development among bees.

A female bee can become either a worker or a queen. Queen bees are larger and live longer than workers. Queen bees are also fertile while workers are essentially sterile. A queen has only one role—to lay eggs—while workers tend the hive, care for the queen and larvae, and for food.

"The incredible thing is that both of these types of female honeybees emerge from the same ," says Florian Wolschin, an assistant research professor in the School of Life Sciences in ASU's College of Liberal Arts and Sciences, is the lead author of the study. "So how does that happen?"

Workers determine the fate of the larvae by what they feed them. The amount and composition of food that the larvae receive determine whether they become workers or queens. People have known this for many years, but exactly what happens inside the cells to create this split isn't completely clear.

Wolschin, Gro Amdam, an associate professor, and Navdeep S. Mutti, a postdoctoral research associate, found that the insulin signaling pathway plays a role in caste development. Insulin is a hormone found in humans and many other animals, and insulin-like peptides have been discovered in bees. Insulin moves glucose—sugar—from the into the body's cells where it can be used.

The researchers suppressed one of the key proteins in this pathway in larvae. The protein, called the insulin receptor substrate (IRS), has been linked to growth, development and reproduction in mice. The researchers fed the altered a queen's diet, but they developed into workers, not queens.

IRS is only one component of the process that decides a bee's ultimate fate. Wolschin says several other molecules are known to play a role, including DNA methyltransferase, juvenile hormone and a protein called TOR.

"Those are all very important and fundamental mechanisms," says Wolschin. "One single part cannot alone be responsible. It has to be the interplay between different mechanisms that finally results in the divergence of queens and workers."

The researchers are now looking at the interconnections between several of these factors. "We want to see if maybe there's a hierarchy involved. Several of the components are probably 'upstream' of other processes. So they serve as mass regulators and switches," says Wolschin.

Honeybees are vitally important to our economy through pollination of crops as well as production of honey, wax and royal jelly. Understanding bee biology is crucial to maintaining this industry in the face of problems like colony collapse disorder.

Wolschin adds that bees also provide an important model system that can help us understand our own biology. For example, scientists have successfully reversed many signs of aging in worker .

"That is pretty unique," says Wolschin. "You don't have other model organisms in aging research that can do that."

Explore further: Male monkey filmed caring for dying mate (w/ Video)

More information: Read the full study here

Related Stories

Royal jelly makes bee queens, boosts nurture case

Mar 14, 2008

New Australian National University research may explain why eating royal jelly destines honeybee larvae to become queens instead of workers – and in the process adds new weight to the role of environmental factors in the ...

Bees may transmit viruses to offspring

Jan 19, 2006

Researchers from the U.S. Department of Agriculture report what may be the first evidence of queen honeybees transmitting viruses to their offspring.

Why do some queen bees eat their worker bee's eggs?

Dec 04, 2006

Worker bees, wasps, and ants are often considered neuter. But in many species they are females with ovaries, who although unable to mate, can lay unfertilized eggs which turn into males if reared. For some ...

Recommended for you

Male monkey filmed caring for dying mate (w/ Video)

Apr 18, 2014

(Phys.org) —The incident was captured by Dr Bruna Bezerra and colleagues in the Atlantic Forest in the Northeast of Brazil.  Dr Bezerra is a Research Associate at the University of Bristol and a Professor ...

Orchid named after UC Riverside researcher

Apr 17, 2014

One day about eight years ago, Katia Silvera, a postdoctoral scholar at the University of California, Riverside, and her father were on a field trip in a mountainous area in central Panama when they stumbled ...

In sex-reversed cave insects, females have the penises

Apr 17, 2014

Researchers reporting in the Cell Press journal Current Biology on April 17 have discovered little-known cave insects with rather novel sex lives. The Brazilian insects, which represent four distinct but re ...

Fear of the cuckoo mafia

Apr 17, 2014

If a restaurant owner fails to pay the protection money demanded of him, he can expect his premises to be trashed. Warnings like these are seldom required, however, as fear of the consequences is enough to ...

User comments : 0

More news stories

Researchers successfully clone adult human stem cells

(Phys.org) —An international team of researchers, led by Robert Lanza, of Advanced Cell Technology, has announced that they have performed the first successful cloning of adult human skin cells into stem ...

Plants with dormant seeds give rise to more species

Seeds that sprout as soon as they're planted may be good news for a garden. But wild plants need to be more careful. In the wild, a plant whose seeds sprouted at the first warm spell or rainy day would risk disaster. More ...

Airbnb rental site raises $450 mn

Online lodging listings website Airbnb inked a $450 million funding deal with investors led by TPG, a source close to the matter said Friday.

Health care site flagged in Heartbleed review

People with accounts on the enrollment website for President Barack Obama's signature health care law are being told to change their passwords following an administration-wide review of the government's vulnerability to the ...