Biophysics: ‘Come into my parlour,’ said the spider to the electrostatically charged fly

Electrostatically charged insects and water droplets can cause the silk threads of spider silk to rapidly deform, potentially enhancing prey capture, a study published in Scientific Reports this week reveals.

Spider-orb webs are aerial traps specialized to catch flying insects of different sizes. Insects can easily acquire electrostatic charge by walking over charged surfaces or by flying in an airstream of charged particles, but the effects of electrical charge on spider-orb webs have remained uncertain.

Victor Manuel Ortega-Jimenez and Robert Dudley evaluated the deformation responses of spider webs by dropping positively charged insects (including honeybees and fruit flies) and water droplets onto the orb web of a cross spider and measuring the resulting web displacement. They show that positively charged insects and water droplets could induce deformations in the spiral web silk threads by up to 2 mm, whereas comparatively neutrally charged insects and water droplets dropped from the same height showed no such deformation.

The findings suggest that a free-flying insect’s electrostatic charge may affect its risk of capture in orb webs, although further research into the link between charge, web deformation and insect capture is needed.