Queen or Worker? Not All Insects Have Defined Social Roles, Researchers Say [VIDEO]
Many types of insects hold distinct social roles within their respective colonies, but researchers have long debated whether leaders – the paralells to queen bees – are born to or voted into their lofty office. After analyzing dinosaur ants and red paper wasps, researchers believe they have uncovered the genetics that gorvern insect hierarchy systems.
In a recent study, researchers from the University of Bristol, the Babraham Institute (Cambridge, UK) and the Centre for Genomic Regulation (Barcelona, Spain) examined individual wasp and ant brains belonging to both queens and worker class subjects. The point was to determine if social class could be explained by variations in gene expression, similar to how honeybees arrange their hives, according to a news release.
Genetic sequencing revealed a subtle, non-random, arrangement of gene networks, suggesting there is no master gene but that many genes are involved with determining social behavior. Dinosaur ants and red paper wasps, like many other insects, switching between roles becuase their genomes remain open and responsive.
"Unlike honeybees, who as larvae are fated irreversibly to be a queen or worker, paper wasps and dinosaur ants are able to switch roles from worker to queen at any point in their life. This flexibility is thought to represent the first stages of caste evolution, when the simplest societies form," Dr. Seirian Sumner, senior author on the paper from the University of Bristol, explained in the release. (Scroll to read more...)
While the queens and workers of each dinosaur ant and red paper wasp population appeared to be very similar, their respective roles can be determined by observing their behaviors and social interactions. To tell individuals apart from other colony members, researchers painted a tiny spot or placed a small identification tag on insects subjects and found that neither species was genetically programmed for a specific, unchangeable role.
"We found very few differences in gene expression and gene functional specialization between queens and workers in both the ant and the wasp," Dr. Solenn Patalano, lead author of the paper from the Epigenetics Program at the Babraham Institute, explained in a statement. "In both, less than one percent of the genome showed noticeable differences in expression levels. This was unexpected as many hundreds of genes are involved in differentiating queens and workers in the honeybee."
Insects such as honeybees posses genes that dictate their position in a heirarchy, which means that workers are often sterile. Queens are responsible for reproduction, and since there is no possibility of promotion for a worker bee, there is simply no need for them to possess the ability to reproduce. Dinosaur ants and red paper wasps are equipped for producing offspring specifically because they are required to take on flexible roles over a lifetime.
Dinosaur ants, Dinoponera quadriceps, are generally found in cool regions of Australia where they spend their time foraging on trees for insects or sweet nectar. Red paper wasps, Polistes Carolina, can be found in Paper-Mache-like nests throughout the eastern U.S. from Texas through Nebraska. The wasps are known for their reddish-brown color and for building some of the largest nests of any wasp species. Both species belong to simple eusocial societies. This means that colony organization can be traced to certain social behaviors, which are sometimes referred to as castes. For example, queens are responsible for reproduction, while workers are required to do hard labor such as forage and build.
This study, recently published in the Proceedings of the National Academy of Sciences, is helping researchers better understand how insects with flexible social structures are able to adapt to change.
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