Data and code for "Structure and mechanics of cockroach antennae confer flexibility and shape strain transmission for proprioception"

A broad class of animals rely on touch sensation for perception.
Among insects, the American cockroach (Periplaneta americana)
uses a pair of soft antennae with distributed sensors to touch its
environment to guide decision making. During touch, forces on the
antenna can activate thousands of mechanosensors. To understand
the content of this sensory information, it is critical to understand
how antenna mechanics shape the transmission of contact forces.
Here, we investigated the mechanical behavior and morphology
of antennae of the American cockroach at the individual annulus
level through experiments, modeling, imaging with micro-computed
tomography (micro-CT), 3D reconstruction of antenna morphology
and finite element modeling (FEM). Our data and model predictions
revealed that the antenna flagellum bends according to a kinematic
chain model, with annuli connected by softer joints. Whereas
the middle region of the antenna consistently fractured under cyclic
bending, the tip region remained intact, revealing mechanical
specialization along the antenna. Micro-CT imaging revealed an
invagination of the exocuticle at annulus intersections of the tip. To
test the hypothesis that this structure could enhance flexibility and
robustness, we used FEM and confirmed that the invagination
allows for larger bending without structural failure (buckling). Applying
FEM to a morphologically accurate kinematic chain model of the
flagellum revealed the relationship between the local strain at the
location of campaniform sensilla, predicting the information available
for antenna proprioception. Taken together, these findings reveal
biomechanical adaptations of insect antennae and provide a critical
step toward a mechanistic understanding of touch sensation in a
touch specialist.