Attachment ability of the southern green stink bug Nezara viridula (Heteroptera: Pentatomidae)
The present paper characterizes the attachment ability of males and females of Nezara viridula (Heteroptera: Pentatomidae) on artificial surfaces (smooth hydrophilic, smooth hydrophobic, different surface roughness) and on both leaf surfaces of the typical host plant species Vicia faba, using a centrifugal force tester and a traction force experiments set up. N. viridula is a serious crop pest in the world and shows attachment devices different from the so far investigated Heteroptera, with a tarsus characterized by distal smooth flexible pulvilli combined with claws and proximal ventral hairy pad. Notwithstanding the different body mass between the sexes, no difference was found between friction forces generated by females and males. Friction force was higher on hydrophilic surfaces than on hydrophobic ones and was lower on both sides of V. faba leaf compared with both hydrophilic and hydrophobic artificial smooth surfaces. On the surfaces with different roughness, the friction force values varied significantly, with the higher attachment ability on the surface with very high asperity size followed by the smooth surface. The lowest attachment was on the surfaces with intermediate asperity sizes. These results could be related to the specific combination of attachment devices of N. viridula.