Attachment ability of sawfly larvae to smooth surfaces

Larvae of the sawfly Rhadinoceraea micans adhere properly to the anti-adhesive surface of their host plant Iris pseudacorus by using three pairs of thoracic legs, seven pairs of abdominal prolegs, and pygopodia, all provided with various smooth adhesive pads. Their attachment performance to smooth flat hydrophilic and hydrophobic glass and Plexiglas surfaces was studied in centrifugal force experiments. Obtained safety factors on Plexiglas were up to 25 in friction, and 8 in adhesion. Although larvae attached significantly stronger to the hydrophilic glass, they attached well also to the hydrophobic one. Pygopodia are suggested to dominate attachment force generation in the centrifugal force experiment. Transverse body position on the centrifuge drum was significantly advantageous for friction force generation than was longitudinal body position. Results are discussed in the context of the sawfly biology and provide a profound base for further detailed studies on biomechanics of sawfly larvae–plant interactions.