A recent study conducted by the Institute for Neurosciences (IN) has shed light on how flies develop their flight stabilizers known as halteres. These small organs, acting as biological gyroscopes, play a crucial role in helping flies maintain stability during flight.

The research, led by José Carlos Pastor Pareja, revealed that halteres are not hollow structures as previously thought. Instead, they are internally connected by a complex cellular system that maintains their rounded shape.

During metamorphosis, the halteres develop from a thin layer of cells. The study found that an extracellular matrix rich in collagen separates the two surfaces of the haltere, which is then degraded to allow the formation of cellular projections connecting both surfaces through a matrix containing laminin.

These internal connections act as biological tensors, resisting forces that could deform the haltere. When this system fails, as observed in genetically modified fruit fly models, the organ loses its essential rounded shape.

The study also highlighted that the haltere is constantly under tension, with forces pulling at its base and anchoring it to the insect's outer cuticle. The internal tensor system within the haltere balances these forces to maintain its geometry.

Advanced electron microscopy and live imaging techniques were used to observe these effects during fly metamorphosis. The team identified cellular projections stabilizing the haltere's shape and counteracting deforming forces.

By utilizing mutant models and analyzing the extracellular matrix, the researchers uncovered a mechanism involving collagen degradation, cell adhesion, and internal tensors that reinforce the structure from within.

These findings offer insights into how organs take shape in animals, beyond the scope of fruit flies. They have implications for developmental biology, tissue engineering, and the design of biomimetic structures.

The collaborative study involved researchers from Tsinghua University, the Severo Ochoa Molecular Biology Center, and the University of Alicante, in addition to the CSIC-UMH Institute of Neurosciences.