Elytra boost lift, but reduce aerodynamic efficiency in flying beetles.

Area of Science:

• Entomology
• Biomechanics
• Aerodynamics

Background:

• Beetles possess two pairs of wings; the forewings, or elytra, are hardened and protect the hindwings and abdomen.
• Elytra are often extended during flight, suggesting a role in aerodynamics, though this is not well understood.

Purpose of the Study:

• To investigate the aerodynamic role of elytra in beetle flight.
• To quantify the effect of elytra on force production and wake dynamics.

Main Methods:

• Quantitative measurements of the beetle's wake.
• Analysis of vortex structures during flight.

Main Results:

• The presence of elytra increased vertical force production by approximately 40%, aiding weight support.
• The wing-elytra combination generated a complex wake with multiple vortices, including wingtip, elytron, and body vortices.
• A negative interaction between the wing and elytron created an opposing vortex, reducing wing span efficiency to approximately 0.77.

Conclusions:

• Elytra contribute significantly to vertical force production in beetles.
• The complex aerodynamics generated by the wing-elytra system come at the cost of reduced flight efficiency compared to birds and bats.