Ant Workers and Queens Shape Their Thoraces to Match Their Tasks

It turns out that the differences between worker ants and queens go far beyond the presence or absence of wings. Scientists have discovered that ants grow the size of their thoracic segments differently depending on the specialized tasks that they'll perform as adults. The findings reveal a bit more about the complex world of ants.

Insects that live in societies, like ants, specialize in certain tasks. More specifically, they show an interesting interplay between their size and shape and their behavior. While species may share a similar set of genes, individuals play different roles and often vary in their appearance. Ants, though, take this to an extreme; queens are large and winged while workers are much smaller and wingless. In order to get a closer look at these morphological differences, the scientists studied ants a bit more closely.

The scientists examined the thorax of most living and extinct ant subfamilies of ants. The thorax is part of the insect body that contains the segments wearing the wings and the legs. In the end, the researchers found that in worker ants the thoracic segment closer to the head is greatly enlarged and filled by strong neck muscles. These muscles power the movements of the head, which in turn contains the jaws that ants use to grab and manipulate objects. Queen ants, in contrast, do not have these strong neck muscles and instead have a reduced segment.

"Our analysis of morphology shows that worker ants are much more than just smaller and wingless versions of queens, and have a body plan that provides great strength and maneuverability to their heads," said Patricia Beldade, one of the researchers, in a news release. "It also shows that queens that start new colonies without the help of workers can have two types of body plans associated to whether they go through a worker-like hunting phase or not."

The findings help explain ants' extraordinary ecological success. In addition, they reveal ants' diversity even among the same species. This shows a little bit more about these amazing insects and how they managed to survive.

The findings are published in the journal eLife.