Insect cuticular growth layers seen under the scanning electron microscope: A new display method.

Area of Science:

• Entomology
• Materials Science
• Microscopy

Background:

• Insect cuticle structure is crucial for understanding growth and biomechanics.
• Previous studies have not fully elucidated the microstructural organization of daily growth layers.

Purpose of the Study:

• To demonstrate the utility of Scanning Electron Microscopy (SEM) for analyzing insect cuticular growth.
• To investigate the microstructural composition of endocuticle helicoids and their relation to growth layers.

Main Methods:

• Utilized Scanning Electron Microscopy (SEM) for high-resolution imaging of insect cuticle.
• Focused on the short-horned grasshopper, *Romalea microptera*, for detailed analysis.
• Examined the orientation and arrangement of chitin fibrils within the endocuticle.

Main Results:

• SEM effectively visualized discrete chitin fibrils comprising the endocuticle helicoids.
• Chitin fibrils are arranged in a staggered orientation, contributing to cuticle properties.
• Surface relief features observed under SEM correlate with daily growth layer patterns.

Conclusions:

• SEM is a valuable tool for studying insect cuticular growth layer microstructures.
• The staggered arrangement of chitin fibrils is a key feature of the endocuticle.
• Surface topography provides insights into the daily deposition of cuticular material.