Growth regulation bringing modularity to morphogenesis of complex three-dimensional exoskeletons

Area of Science:

• Developmental Biology
• Evolutionary Morphology
• Biophysics

Background:

• Arthropod appendages, such as beetle horns, exhibit diverse 3D morphologies.
• These structures arise from non-uniform epidermal growth during development.
• The precise mechanisms linking morphogen distribution to complex shape generation remain unclear.

Purpose of the Study:

• To investigate the relationship between epidermal growth regulation and the resulting 3D structures.
• To theoretically model how planar epidermis can form complex shapes like beetle horns.

Main Methods:

• A deductive growth model was employed to simulate epidermal morphogenesis.
• The model correlated morphogen distributions with non-uniform tissue growth.
• Exploration of how heterochronic expression of multiple morphogens influences shape generation.

Main Results:

• Demonstrated that heterochronic expression of multiple morphogens can generate diverse 3D structures.
• Showcased the flexible fusion of simple shapes to emulate complex arthropod outgrowths.
• The model successfully generated shapes mimicking beetle horns and other complex structures.

Conclusions:

• Morphogenesis via regulated non-uniform epidermal growth offers developmental stability and modularity.
• This mechanism provides a framework for understanding the evolution of diverse arthropod morphologies.
• Findings offer insights into the developmental basis of evolutionary diversification in arthropods.