Extreme suction attachment performance from specialised insects living in mountain streams (Diptera: Blephariceridae)

Abstract

Suction is widely used by animals for strong controllable underwater adhesion but is less well understood than adhesion of terrestrial climbing animals. Here we investigate the attachment of an aquatic insect larva (Blephariceridae), which clings to rocks in torrential streams using the only known muscle-actuated suction organs in the insect kingdom. We measured their attachment forces on well-defined rough substrates and found their adhesion was much less reduced by micro-roughness than terrestrial climbing insects. In vivo visualisation of the suction organs in contact with microstructured substrates revealed that they can mould around large asperities to form a seal. Moreover, we showed that spine-like microtrichia on the organ are stiff cuticular structures that only make tip contact on smooth and microstructured substrates. Our results highlight the performance and versatility of blepharicerid suction organs and introduce a new study system to explore biological suction.

Attachment of bioinspired microfibrils in fluids: transition from a hydrodynamic to hydrostatic mechanism

“…The results presented here may also advance the understanding of natural adhesive systems that function under wet conditions, as most natural adhesive systems are compliant and usually have complex, irregular geometries. Examples range from insects [25,26,29], and tree frogs [27,48,49], to octopuses, net-winged midge larvae [28,50], and clingfish [51,52].…”

Wetting of the tarsal adhesive fluid determines underwater adhesion in ladybird beetles

“…While most of the studies on insect adhesion focused on terrestrial species, underwater insect attachment is much rarer and has been relatively unexplored. Some aquatic insects such as diving beetles ( Chen et al, 2014 ) or midge larva ( Kang et al, 2020 preprint) use suction cups to adhere to surfaces ( Ditsche-Kuru et al, 2012 ; Ditsche and Summers, 2014 ). However, underwater adhesion mediated by secreted liquids requires the displacement of the water at the interface first and a spreading of the fluid on the substrate.…”