Insect cuticular hydrocarbon composition influences their interaction with spider capture threads

Area of Science:

• Evolutionary biology
• Biophysics
• Entomology

Background:

• Spiders and insects co-evolved, with insects forming the primary prey for spiders.
• Spider webs are specialized traps, with cribellate silk being an ancient prey-capture thread.
• Cribellate threads lack adhesive, relying on nanofibres and van der Waals forces for insect capture.

Purpose of the Study:

• To investigate how insect cuticular hydrocarbon (CHC) composition influences adhesion to cribellate spider silk.
• To understand the biophysical interactions between CHCs and cribellate threads.

Main Methods:

• Studied the interaction between cribellate threads and CHC layers from four insect species with distinct CHC profiles.
• Analyzed the differential migration of various hydrocarbon types into the silk.
• Assessed the impact of molecular structure and ambient temperature on hydrocarbon viscosity and migration.

Main Results:

• Observed differential migration of CHCs into cribellate threads based on insect species.
• Demonstrated that hydrocarbon molecular structure and viscosity, influenced by temperature, affect CHC migration.
• Showed that adhesion forces vary significantly with the CHC composition of the insect cuticle.

Conclusions:

• Insect CHC composition directly impacts adhesion to cribellate spider silk.
• Spiders may exert selective pressure on the CHC profiles of their insect prey.
• Findings align with biophysical predictions regarding hydrocarbon interactions.