Microstructures Create Reversible Attachment

Biological Strategy

Dragonflies and damselflies

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Attach Temporarily

Living systems must sometimes, temporarily, stay in one place, climb or otherwise move around, or hold things together. This entails attaching temporarily with the ability to release, which minimizes energy and material use. Some living systems repeatedly attach, detach, and reattach for an extended time, such as over their lifetimes. Despite being temporary, these attachments must withstand physical and other forces until they have achieved their purpose. Therefore, living systems have adapted attachment mechanisms optimized for the amount of time or number of times they must be used. An example is the gecko, which climbs walls by attaching its toes for less than a second. Other examples include insects that attach their eggs to a leaf until they hatch, and insects whose wings temporarily attach during flight but separate after landing.

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Insects

Class Insecta (“an insect”): Flies, ants, beetles, cockroaches, fleas, dragonflies

Insects are the most abundant arthropods—they make up 90% of the animals in the phylum. They’re found everywhere on earth except the deep ocean, and scientists estimate there are millions of insects not yet described. Most live on land, but many live in freshwater or saltwater marshes for part of their life cycles. Insects have three distinct body sections: a head, which has specialized mouthparts, a thorax, which has jointed legs, and an abdomen. They have well-developed nervous and sensory systems, and are the only invertebrate that can fly, thanks to their lightweight exoskeletons and small size.

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The neck attachment of a dragonfly's head protects it from mechanical stresses by arresting it using microstructures that create friction.

Last Updated September 17, 2018

References

“The arrester or fixation system of the head in adult Odonata is unique among arthropods. This system involves the organs of two body segments: the head and the neck. It consists of a skeleton-muscle apparatus that sets the arrester parts in motion. The parts comprise formations covered with complicated microstructures–fields of microtrichia on the rear surface of the head and post-cervical sclerites of the neck. The arrester immobilizes the head during feeding or when the dragonfly is in tandem flight. Thus, it may serve as an adaptation to save the head from violent mechanical disturbance and to stabilize gaze in a variety of behavioural situations.” (Gorb 1999:525)

“The arrester system includes the adjusting organs of two body segments–the head and neck–and consists of (i) the skeleton-muscle apparatus that moves the head and neck sclerites, (ii) co-opted microsculptures, which are fields of microtrichia on the rear surface of the head (MFH) and on the post-cervical sclerites of the neck (SPCs), (iii) the secretory apparatus consisting of epidermal cells, which produces lipid substances which pass through porous channels in the cuticle into the region of contact between the MFH and SPCs, and (iv) sensory organs monitoring contact between the MFH and SPCs and the position of the SPCs relative to the other neck sclerites (Gorb 1991a)”. (Gorb 1999:525)

Journal article

Evolution of the dragonfly head-arresting system

Proceedings of the Royal Society B: Biological Sciences, 266: 525-535 | 07/03/1999 | Gorb SN

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Reference

Journal article

Ultrastructural architecture of the microtrichia of the insect cuticle

Journal of Morphology, 234: 1–10 | 01/10/1997 | Gorb SN

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