The study focuses on the evolution of “eusociality,” a system of collective living in which most members of a female-centric colony forego their reproductive rights and instead devote themselves to specialized tasks – such as hunting for food, defending the nest or caring for the young – that enhance the survival of the group. The study appears in the Proceedings of the National Academy of Sciences.
Eusociality is a rarity in the animal world, said Gene Robinson, a University of Illinois entomology professor and the director of the Institute for Genomic Biology, who led the study. Ants, termites, some bees and wasps, a few other arthropods and a couple of mole rat species are the only animals known to be eusocial.
Among bees, there are the “highly eusocial” honey bees and stingless bees, with a caste of sterile workers and a queen that functions primarily as a “giant, egg-laying machine,” Robinson said. And there are other, so-called “primitively eusocial” insects, usually involving a single mom who starts a nest from scratch and then, once she has raised enough workers, “kicks back and becomes a queen,” he said.
Illinois entomology professor Sydney Cameron, a collaborator on the study and a social insect evolution expert, dislikes the term “primitively eusocial” because it suggests that these bees are on their way to becoming more like stingless bees or honey bees. Eusociality is not a progressive evolution from the “primitive” to the “advanced” stage, she said.
“They’re not striving to become highly eusocial,” Cameron said. “They don’t say to themselves, ‘If only I could become a honey bee!’ ”
“People talk about the evolution of eusociality,” Robinson said. “But we want to emphasize that these were independent evolutionary events. And we wanted to trace the independent stories of each.”
To accomplish this, the researchers worked with Roche Diagnostic Corp. to sequence active genes (those transcribed for translation into proteins) in nine species of bees representing every lifestyle from the solitary leaf-cutter bee, Megachile rotundata, to the highly eusocial dwarf honey bee, Apis florea. Then Illinois crop sciences professor and co-author Matt Hudson used the only available bee genome, that of the honey bee, Apis mellifera, as a guide to help assemble and identify the sequenced genes in the other species, and the team looked for patterns of genetic change that coincided with the evolution of the differing social systems.
“Are there genes that are unique to the primitively eusocial bees that aren’t found in the highly eusocial bees?” Cameron said. “Or if you lump all the eusocial bees together, are there unique genes that unite those groups compared to the solitaries?”
The analysis did find significant differences in gene sequence between the eusocial and solitary bees. The researchers also saw patterns of genetic change unique to either the highly eusocial or primitively eusocial bees. The frequency and pattern of these changes in gene sequence suggest “signatures of accelerated evolution” specific to each type of eusociality, and to eusociality in general, the researchers reported.
“What we find is that there are some genes that show signatures of selection across the different independent evolutions (of eusocial bees),” Robinson said. “They might be representatives of the ‘gotta have it’ genes if you’re going to evolve eusociality. But others are more lineage-specific.”
This study was made possible with a one-gigabyte sequencing grant from 454 Life Sciences (Roche Diagnostics Corp.) by way of the Roche 1GB contest. The National Science Foundation and the National Institutes of Health also supported the research.
The study team also included researchers from Cornell University and from the Program in Ecology, Evolution and Conservation Biology and the Institute for Genomic Biology at Illinois.
Diana Yates | Source: University of Illinois
Further information: www.illinois.edu
More articles from Life Sciences:
Study details genes that control whether tumors adapt or die when faced with p53 activating drugs
23.05.2013 | University of Colorado Denver
Scientists announce Top 10 New Species
23.05.2013 | Arizona State University
New indicator molecules visualise the activation of auto-aggressive T cells in the body as never before
Biological processes are generally based on events at the molecular and cellular level. To understand what happens in the course of infections, diseases or normal bodily functions, scientists would need to examine individual cells and their activity directly in the tissue.
The development of new microscopes and fluorescent dyes in ...
A fried breakfast food popular in Spain provided the inspiration for the development of doughnut-shaped droplets that may provide scientists with a new approach for studying fundamental issues in physics, mathematics and materials.
The doughnut-shaped droplets, a shape known as toroidal, are formed from two dissimilar liquids using a simple rotating stage and an injection needle. About a millimeter in overall size, the droplets are produced individually, their shapes maintained by a surrounding springy material made of polymers.
Droplets in this toroidal shape made ...
Frauhofer FEP will present a novel roll-to-roll manufacturing process for high-barriers and functional films for flexible displays at the SID DisplayWeek 2013 in Vancouver – the International showcase for the Display Industry.
Displays that are flexible and paper thin at the same time?! What might still seem like science fiction will be a major topic at the SID Display Week 2013 that currently takes place in Vancouver in Canada.
High manufacturing cost and a short lifetime are still a major obstacle on ...
University of Würzburg physicists have succeeded in creating a new type of laser.
Its operation principle is completely different from conventional devices, which opens up the possibility of a significantly reduced energy input requirement. The researchers report their work in the current issue of Nature.
It also emits light the waves of which are in phase with one another: the polariton laser, developed ...
Innsbruck physicists led by Rainer Blatt and Peter Zoller experimentally gained a deep insight into the nature of quantum mechanical phase transitions.
They are the first scientists that simulated the competition between two rival dynamical processes at a novel type of transition between two quantum mechanical orders. They have published the results of their work in the journal Nature Physics.
“When water boils, its molecules are released as vapor. We call this ...
23.05.2013 | Physics and Astronomy
23.05.2013 | Health and Medicine
23.05.2013 | Ecology, The Environment and Conservation
17.05.2013 | Event News
15.05.2013 | Event News
08.05.2013 | Event News