Biomimetics, Micro-design, Arctium minus et al Hook and Velcro – A PhD and a Virtual Textbook on Biological Attachment Mechanisms and their Mimicking

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Part I: The Biomimetic study of Cellulose Hooks: Burdock (Arctium minus) OR How to make a cellulose hook that’s small and efficient.

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ZOOLOGICAL BACKGROUND AND ARRANGING THE SPECIMENS AS A FUNCTION OF MATERIAL

APPENDIX – ZOOLOGICAL BACKGROUND AND ARRANGING THE SPECIMENS AS A FUNCTION OF MATERIAL

Keywords in the Section:
systematics, paleontology, cladistics, functionality, rigid and permanent attachments,

Section 2.1 contains a description of related fields of research and a glossary of terms used within this report.
1. GLOSSARY AND GENERAL BIOLOGICAL BACKGROUND MATERIAL

All definitions related to insect morphologies are derived from Evans [‎1] and Nachtigall [‎2]. Similarly for plant morphology Bell [‎2] was the main source.

Subject Definitions

These are very general background definitions of terms I encountered in my background reading. Whilst perhaps not strictly relevant to engineering, they are of scientific interest to me and so I have included them here.

Paleontology: The study of fossilized remains of plants and animals to learn about life through the geologic past.

Systematic biology: Biological information organised in a taxonomic or phylogenic manner.

Taxonomy: The science of organising living things into groups.

Phylogeny: The natural, evolutionary ancestor/descendant relationships between groups of living things. Such groups are called taxa.

Linnaeus classification: Carl von Linne used an organism’s morphology to categorise it and thereby to establish a classification hierarchy with five levels (Kingdom, Class, Order, Genus, Species). Phylum and Family were later added:

Kingdom (i.e. Plant or Animal)
Phylum (called the Division in the Plant Kingdom)
Class
Order
Family
Genus
Species

The Linnaeus system has since been superceded by a system of biological classification introduced by Carl Woese in the ‘70’s. In his new system, all living organisms are grouped into three domains:

Archaea – this group was considered to be bacteria until they were found to be different in cell compositions and metabolisms and so were given their own grouping. Many of them live in extreme environments. It is unlikely that any of these organisms will have hooks.
Bacteria – microscopic, mostly single-celled with simple cell structure, without nucleus and organelles of more complex life forms. Again, these organisms are unlikely to have hooks.
Eukaryotes – the domain of Eukaryotes contains the kingdoms of Animalia, Plantae, Fungi and Protista.

Binomial System: Organisms are identified by their genus and species name.

Arthropoda (Arthropoda = jointed foot): These are the most successful life-form on Earth in terms of variety. This phylum includes over 1 million species.

• They have a versatile exo-skeleton that is highly protective and mobile. This prevents dehydration.
• They exhibit segmentation and tagmosis (see glossary below): for more efficient locomotion, feeding and sexual reproduction.
• In land organisms the cells are directly ventilated through a tracheal system.
• They have highly developed sensory organs
• They exhibit complex behaviour and may have evolved social systems
• There may be an ecological separation of life stages thereby reducing competition by metamorphosis.
• They are able to exploit a wide variety of ecological niches.

Insects belong to the phylum Arthropoda, which also includes spiders, mites, and centipedes. The class Insecta is divided into two sub-classes, Apterygota (wingless) and Pterygota (winged).

Sub-class Pterygota is divided into two infra-classes: Paleoptera and Neoptera. Paleoptera cannot fold their wings back (dragonflies, mayflies) and Neoptera can hold their wings back against their body.

Glossary

Elytra: fore-wings that have been modified such as in Coleoptera (beetles) for instance, into hard protective covers.

Cladistics: a system of phylogenic classification that uses certain features of organisms, called shared derived characters, to establish evolutionary relationships

Phylogenic tree: used to show the evolutionary relationship thought to exist among groups of organisms. A phylogenic tree represents a hypothesis, generally based upon a fossil record, morphology, embryological patterns of development, and chromosome and macromolecules.

Homologous features: similar features that originate from a shared ancestor.

Tagmosis: the evolutionary process of fusing and modifying segments.

Two Methods of Classifying Hooks

In the sections immediately following I have directly summarised from Nachtigall [‎3] and Gorb [‎4].

The world wide web was also an important source of immediate definitions and images, from the less scientific to formal research papers.

The first reference for specimens with hook attachments [‎4] was published in 1973 and has the subtitle “The Comparative Morphology and Bioengineering of Organs for Linkage, Suction and Adhesion”. The book contains a subsection devoted solely to organisms that have features that use a hooking action for attachment. In this text Nachtigall includes descriptive mechanical analogues for the biological attachment mechanisms he has studied.

My second main hook reference [‎5] was published in 2001 and concentrates on a subset of biological attachment mechanisms, those of entomology and therefore made of insect cuticle (chitin). These are generally relatively small attachment mechanisms and the text has the added feature of redressing the classification of hooks, that is, the hooks are defined not according to shape but according to functionality.

The definition of a hook according to functionality requires a direct reference to the substrate in which the hook is engaged. The environment can thus be considered to be a biological design parameter because it has a direct impact on the shape and strength of the hook.

Sections ‎2.3.1, ‎2.3.2, and ‎2.3.3 are lists and images of biological examples extracted from [‎3]. Section ‎2.4 is a summary from [‎4].

Images of attachment mechanisms have been included where possible.

Classification by Morphology – Nachtigall
Rigid and Permanent Attachments

In Chapter One Nachtigall begins by defining the set of mechanical joining techniques as laid out in the table below:

Releasable Permanent
Rigid Electrical plug and socket Riveted plates of a ship’s hull
Flexible Tailor’s hook and eye The hinge of a door
Table 1 – Mechanical mechanisms (Nachtigall p1)
But he groups his biological attachment mechanisms (based on morphology) into two main subsets:

a) Rigid and permanent, or
b) Releasable

He does this because, he says, it is difficult to categorise biological attachment mechanisms according to the strict categories of the mechanical connections as per Table 1.

His set of biological rigid and permanent attachments includes:

a) Special devices: In engineering these are screws, pins or some other third device that is present only to facilitate attachment. Such types of attachment devices (with these separate, dedicated structures) do not exist in nature.

b) Amorphous bonding material: Organisms secrete some form of “glue” or “cement” that can utilise hard foreign bodies such as grains of sand to form a composite material. Examples include the gelatinous matrix that sometimes surrounds cells that form a colony in unicellular marine algae (e.g. Prymnesiophyta, Stephanosphaera, Gonium, Eudorina, Pandorina, Volvox), caddis-fly larvae which make their own matrix body sheath (e.g. Limnophilus, Phryganea) and polychaete worms that build free-standing tubes above the sand of their burrows by combining their body wall secretions with foreign bodies such as sand grains and shells debris (e.g. Arenicloa, Terebellomorphs, Sabellariids, Sabellids).

c) Softening and re-hardening of material: This definition is used to describe the growing together or fusion of one or more organisms. The quoted example is the formation of a callus when bone is healing. Nachtigall compares this process to welding together two separate parts in conventional engineering.

d) Connection by anchoring and interlacing: The roots of higher plants grow into a substrate, interweave and branch for anchorage. The secondary processes that emerge such as enlargements or branching take on a secondary anchoring function.

Fish parasites of the Phylum Arthropoda such as Copepods, Branchurians, Isopods, mites and bi-valves can have outgrowths that penetrate into the flesh of the fish. Commonly they will inhabit the gills, the mouth and the outer skin of a fish. Figure 2 below is two SEM images of Argulus, a sea louse that is an ectoparasite with modified maxillae that grow “downwards” between the scales of a fish and into the underlying flesh for anchorage. In some species these can penetrate through the flesh to the heart of the fish. (Figure 2)

i) ii)

Figure 2 – i) and ii) Argulus, branchurian parasite of fish. The maxillae are modified for attachment (indicated by arrow A) [‎I].
e) Interlocking joints and mitre interlocks: These are found between the skeletal plates of barnacles where two plates have their edges shaped so that they fit snugly together. Beetle elytra (wing covers) have bevelled edges that fit together and secondary interlocking is provided by the fitting of tooth-like projections of one plate into corresponding holes on the other.

There can be simultaneous coarse and fine interlocking where ridges and grooves have a double interlock because the ridge is slightly over-sized. If the ridge and groove are not straight it gives additional interlock strength. The Balanus improvisus barnacle has a rabbet joint with tooth-like secondary interlock. (Figure 3, Figure 4 and 5)

Figure 3 A – Miter joints between basal and lateral plates of balanids,
B – Halved joint in a balanid, C – Compressed aggregation of balanids (Nachtigall p15)

i) ii)
Figure 4 – i) Giant Acorn barnacle Balanus nubilis ii) Acorn barnacle structure [‎II] and [‎III‎II‎III]

RIGID AND PERMANENT – SPECIES FOR FURTHER STUDY

a) Hydroporos ferrugineus (water beetle) – the elytra have a rabbet joint with a double tongue and groove (Figure 5).

Figure 5 – Hydroporous ferrugineus (Nachtigall p16)
76 – interlocking of abdomen and elytra
77 – interlocking of scutellum and elytra
78 – double tongue and groove joint between the elytra

b) Lamellicorn beetles have 15 clasps on their elytra.
c) Stephanolepas (a type of barnacle) has a mitre joint with deep tongue and groove connection.
d) Carabidae ground and tiger beetles are large beetles with a permanent mortis joint between elytra.
e) Cnemidotus water beetles have elytra with a locking mechanism.
f) Gygrinidae (whirligig beetles), hydrobiidae (spiral snails), haliplidae (crawling water beetles), dryopidae (water beetles) all have elytra that are watertight.
g) Siliphidae (carrion beetle) have sealed elytra to prevent moisture loss in their arid environments.

Releasable attachments of two matchng structures

Nachtigall defines releasable attachment mechanisms as those mechanisms allowing two different structural components to be quickly coupled and decoupled. The two parts are held together firmly as long as the connection is maintained such as key-in-lock or plug-in-socket type mechanisms with an exact morphological correspondence between mating parts.

For example, the sex organs of copulating mosquitos, dragonflies and mayflies he describes as resembling an electrical socket in functionality. They are able to maintain the connection once it has been made against the vibrations and disturbances of in-flight copulation because their sex organs have structures that match and interlock.

He groups both rigid and flexible releasable attachments together. By his classification system, the group of releasable attachments (both rigid and flexible) is made up of two main groups:

a) Connection by two complementary parts, and
b) Attachment by one specialised device.

Nachtigall lists

• plug-in-socket,
• hook-and-eye,
• snap fasteners and
• multiple connections

as mechanical analogues to some of the complentary-part devices. These are described in the next four sub-sections.

PLUG-IN-SOCKET

A rod-like component is introduced axially into a corresponding tube-like component. The connection is secured against 3 kinds of displacement by the use of:

a) A tongue and groove against rotation about the longitudinal axis.
b) Guide channels with matching surfaces to prevent tilting with respect to the longitudinal axis.
c) External clamping and internal anchoring to prevent displacement along the longitudinal axis. (Figure 6)

Figure 6 – Plug and socket analogue in copulation of the midge Limnophyes pusillus (Nachtigall p29)

Some examples of organisms that have plug and socket-type joints are:

a) copulating insects such as the dragonfly,
b) crocodiles, with teeth that fit into holes in the opposing jaw,
c) the undulating ridges of large clams Tridacna,
d) the midge Tanytarsus sylvaticus, and
e) copulating yellow fever mosquito’s Aedes aegypti. (Figure 7)
.

Stage One Stage Two Fully-docked!

Figure 7 – Egyptian mosquitos Aedes aegypte approaching the copulatory position with the final engagement of two hook mechanisms (Evans p23).
HOOK-AND-EYE

These connections are accomplished by engaging the hook of one body part with the eye of another and they are good for tension but not for tilt or rotation.

The presence of guide grooves can prevent tilt in some species and rotation may be prevented by the presence of two hooks of the same type next to each other but with the greatest possible distance of separation between them to increase the opposing rotating moment. For example, bird mites have genitalia that lock together, with a flange-capsule structure on the female dorsal surface matching capstan-like protuberances on the posterior ventral surface. In this case the female flange guides the male capstan into the correct “docking” position for insemination (see Figure 8 – (Nachtigall p35)).

A B

C

Figure 8 – (Nachtigall p35)
A – Bird mite Dermanyssus [‎IV]
B – In copulation the male slides over the top of the female to engage sex organs
C – Capstan and flange of engaged bird mite sex organs (Pterophagus strictus)

SNAP FASTENERS

a) As per common engineering terminology, the male is the peg that is expanded at the end and the female is a socket of the same diameter as the peg.
b) In squid, the mantle is joined to the body by two snap fasteners. The female socket (mantle) will have an inner rim reduced slightly by some spring arrangement (such as cartilage) to maintain a seal when the muscular mantle contracts and seals to expel water under pressure down the funnel, for propulsion through the water. e.g. squid mantles Symplectoteuthis and Grimalditeuthis, Cranchidae, Oegopsidae. (See Figure 9 – Snap-type connection in Sepia officinalis (Nachtigall p38)

Figure 9 – Snap-type connection in Sepia officinalis (Nachtigall p38)

c) The tentacle suckers on the two long tentacles of some squid species have a modified system of suckers, with multiple hooks for holding prey. A system of studs and sockets on the tentacle surfaces above and below the hooked sections of each tentacle interact and connect when the prey is clasped by an opposing tentacle, thus aiding the clasping effort. See squid Onychoteuthis, Abralia, Galiteuthis.(see Figure 10 through to Figure 14)

Figure 10 – Tentacular fasteners (Nachtigall p38)

Figure 11 – Squid Abralia [‎V‎V‎III]

Figure 12 – Squid Onychoteuthis [‎VI]
Figure 13 – Squid Galiteuthis glacialis [‎VI]

Figure 14 – Squid Galiteuthis glacialis (drawing) [‎1‎V‎VI]

MULTIPLE CONNECTIONS

A mechanical example of multiple connections is a zipper, where a separate slider draws two edges of complementary morphologies together. Such sliders do not exist in nature and from the notes in Nachtigall it would seem that multiple connectors are mostly modified systems of alternate teeth, that vary greatly in modifications from simple interlocking rows of a few teeth to the interlocking of the two hemielytra of the north American water bug Plea striola where a great degree of interlocking is required to maintain the water tight seal when the bug is submerged.

Radiolaria are protista, uni-cellular organisms known for their geometric form and their symmetry because they produce a skeleton of crystal silica. They date back to the Cambrian age and some use delicate interlocking shell margins of hooks and eyes for attachment.

Figure 15 – Radolaria (Nachtigall p42)

Releasable attachements by one structure

Nachtigall lists

a) clamps,
b) grippers,
c) hooks for special substrates,
d) multiplehook devices,
e) probabilistic fasteners, and
f) expansion fastenings.

CLAMPS – (BIOLOGICAL ANALOG: THE STRUCURES ON PREHENSILE LEGS OF INSECTS)
• Vices – e.g pincer wasps, family Dryinidae, mantids.
• Split-sleeve clamps: consider the notched antenna cleaner in foreleg of honey bee (see Figure 16 and Figure 17).

Figure 16 – Antenna cleaning apparatus of honey bee (Apis mellifera) (Nachtigall p38)

1. 2.
3. 4.

Figure 17, 1-4: SEM’s of the vice mechanism of the praying mantis, zooming in on a single tooth to show surface morphology (Saunders, 2002).

• Forceps and medical equipment: consider the beaks of many birds – they have been copied in many surgical instruments that perform similar tasks. (see Figure 18)
Figure 18 – Clockwise from top left: An eagle, a vulture, Anarhynchus frontalis, a spoonbill (x2) (Nachtigall p52)

• Nutcracker type
• 4 Jaw grippers
• Antennae of some insects have prehensile joints that can be used for gripping the mate during copulation.

HOOKS FOR SPECIAL SUBSTRATES:

Hooks are used to:

• Connect insect wings reversibly with one another
• To attach the body of an animal to some substrate
• To manipulate particles of food and other objects.

In the case of wing connectors (see Figure 19), Lepidopterans (butterflies and moths) have 2 types of hook mechanisms, jungate (the hooking mechanism extends from the forewing) and frenate (the hooking mechanism extends from the hindwing).

A B
Figure 19 – Wing connections jungate (A) and frenate (B) (Nachtigall p61)

Hooks are also used to join the forewings and hindwings of:

• Bugs
• Hymenopterans (bees, wasps, ants, sawflies), particularly insects with 2 pairs of wings that beat with a high frequency such as bees (Figure 20), shield moths (which both have finely matched hook mechanisms) and hawkmoths (Manduca sexta) (Figure 21 – Manduca sexta (Hawkmoth) in flight). The honeybee Apis mellifera has a single row of fine hooks (hamuli) on the costal vein of the hindwing which catch upon the undercut ridge of the posterior margin of the forewing.

Figure 20 – The connections between the wings of Apis mellifera seen from above and a honey bee in flight. (Nachtigall p61) [‎VIII‎VI]

Figure 21 – Manduca sexta (Hawkmoth) in flight [‎VII]

• Pentatomid beetles of the genus Palomena have a snap mechanism against tensile stress worth looking at. Also Graphosoma italicum. (Figure 22 and Figure 23)

Figure 22 – Shield bug Palomena [‎X‎VIII]
Figure 23 – mating shield bugs Graphosoma [‎IX]

• Pyrrhocoridae (red bugs, Figure 24), winged heteropteran bugs Gerridae (water striders, Figure 25), and Homoptera (cicadas, leafhoppers, aphids, scale insects and mealy bugs etc) similarly, all having hooking mechanisms clasping their elytra together.

Figure 24 –pale cotton stainer bug Pyrrhocridae: Dysdercus sidae [‎X]
Figure 25 – water strider Gerridae [‎XI]

• Similaly, european Ciccada Triecphora vulnerata (Cercopidae, Figure 26) and Snakeflies (Raphidioptera, Trichoptera, Mecoptera, Figure 27) and sand flies Rhyacophila dorsalis have wing connectors.

Figure 26 – female cicada T.pruinosa [‎XII]
Figure 27 – Scorpion fly (Mecoptera panorpidae) ‎XV‎XIII]

ANCHORS

Sessile animals have special clinging or fixation organs:

• The oncomiracidium (Phylum Platyhelminthes, Class Monogenea) (Figure 28) are generally ectoparasites in the gills or body surface of fish and typically dorso-ventrally flattened, acoelomate with no anus and bilaterally symmetrical, or endoparasitic in the buccal cavity, cloaca or bladder. They have a large posterior sucker or opisthaptor as an attachment mechanism which is a disc with a double circle of hooks, each hook like a “halberd”with a shaft, sharp cutting edge and a terminal process on one side.

• Branchiuran crustacean or carp lice have suckers and angled hooks at the base of the first pair of antenna (Figure 29).

Figure 28 – Oncomiracidium (drawing) [‎XVI‎XIV]
Figure 29 – fishlouse Branchiuran crustacean (also see Figure 2) [‎XV]

• Blood-sucking isopods: Gnathia live on fish and have boat-hooks and harpoon hooks to grasp host fish and attach themselves to them (Figure 30).

Figure 30 – Gnathia maxilaris [‎XVI]

• Kalyptorhynchia (turbellarian worms) have conical pincers which have a pair of hooks at the tip which they dig into the flesh of prey.
• There are also instances of two rows of hooks acting in opposition to each other, for example, Sea stars (Pectinate pedicellariae).
• Peacock, heron, dipper and woodpecker tongues are horny with edges with keratinised teeth. These teeth are saw-like and serve to prevent the prey working loose when they are speared by the tongue. (Figure 31)

Figure 31 – Woodpecker tongue showing keratinised teeth [‎XVII]

There are many climbing plants of which the most successful make use of spines or hooks to attach themselves to the host plants.

• Gleichenia linearis is a tropical rain forest fern and palms of Plectocomia (Figure 32).

Figure 32 – Plectocomia himilayana showing climbing spines [‎XX‎XVIII]

• Uncaria have climbing hooks on their stems that anchor into rough or moldering substrates (Figure 33).

Figure 33 – Uncaria with the red arrow indicating typical hook position [‎XXI‎XIX]

• The stalk of the hop plant has longitudinal climbing hooks and the runner bean has climbing hairs in the shape of crampons.

MULTIPLEHOOK DEVICES:

• Trypanorhyncha (tapeworms of the cestode order) (Figure 34) have arrays of hooks, macrohooks, microhooks, microhooklets and hook chains.

Figure 34 – tapeworm trypanorhyncha lascisthynchus [‎XXII‎XX]
PROBABLISTIC FASTENERS (RANDOM HOOKING OR “BURR”-TYPE DEVICES)

Nachtigall has divided this group into devices obeying

a) The Burr Principle (having hooks),
b) The Comb Principle (no hooks),
c) The Feather Principle (barbs and barbules) or
d) The Microhook Principle (fields of tiny hooks)

These devices are described below.
a) Burr principle

• Species Arctium lappa (burdock) (Figure 35)
• Agrimonia eupatoria The fruits of both of these consist of round fruits with rings of barbs having long shafts and single barbs. (Figure 36)

Figure 35 – Burdock Arctium lappa [‎XXIII‎XXI]
Figure 36 – A. eupatoria [‎XXII]

• Cynoglossum spine tips have a double anchor.
• Galium (bedstraw) has thousands of fine barbs on its climbing stem.(Figure 37)

Figure 37 – Bedstraw Galium [‎XXIII]

• Bellostoma stouti (a type of fish) lays eggs that have bundles of hornlike threads at each end with “buttons” at the tip. In water these anchor filaments extend to catch the hooks of nearby eggs.
• Acanthocephalan worms have a proboscis that can invert so that the ring of hooks points inwards. When internal pressure is increased the teeth appear “at the margin” and are turned to the outside where they catch into the villi of the host’s gut. It uses a peristaltic action to manoeuvre through the gut. (Figure 38)

Figure 38 – Echinorhynchus salmoides acanthocephalan worm [‎XXIV]

• Kinorhyncha (of the class Aschelminthes) have a crest of hooks on their heads. They use this as a “mud” anchor which anchors them to or helps them to move about, on the sea floor. See also echiuroid worms.
• Cat and cow tongues as a brush and curry-comb since the tongue is covered in fields of “re-curved, horny teeth”.

b) The Comb Principle

Consider rough hair being combed with a very fine tooth comb. The comb snags because hairs running at angles to one another become entwined. This principle is used in ecto-parasitic insects living in the fur of vertebrates. The combs are called ctenidia and are one or more rows of closely and evenly spaced bristles.

• Siphonaptera (fleas)
• Nycteribiidae (batflies)
• Polyctenidae (bat bugs)
• Platypsyllus castoris (beaver beetle)

c) Feather Principle

The vane of a feather consists of a number of side branches called barbs. Each barb has “second order side branches” called barbules.
A feather vane can be broken up into segments by pulling in a direction perpendicular to the barb longitudinal axis.

Figure 39 – a) hook barbule b) bow barbule c) probabilistic fasteners on hook and bow barbules interlocked (Nachtigall p75)

One side of the barbule has hook barbules and the other has rows of bow barbules. It is a probabilistic fastening with no particular matching of elements required. The vane is allowed to separate under strong local pressures into segments because otherwise the vane would be destroyed. (Figure 39)
The hook barbule has small “inward curving spurs at its distal end” to prevent the attachment from separating by axial sliding.

d) Micro hook Principal

Geckonidae and some Iguanidae (Anolis) have “leaf-like broadenings of fingers and toes called digital pads or discs” (p78) (even on the tip of the tail sometimes). The surfaces of these pads have transverse lamellae that are covered in dense rows or brushes of tiny bristles. Increased blood pressure in the capillary system of the pads causes the brushes to be pressed firmly against the substrate. Each bristle in turn has a tuft of hundreds of minute processes with tips bent like hooks. These hooked tips are thought to interact with the most microscopic of surface irregularities and to utilise forces of a electrical (surface atomic and molecular charges) or capillary (gluing with water) nature.

Classification by Function – Gorb

Gorb follows a classification definition based on functionality.

For the class of insect cuticle attachment devices he defines the functions:

a) Hooking to the substratum
b) Animal associations: phoresy (the behaviour of animal dispersal using other animals), parasitism, predation
c) Hooking within biological tissues
d) Attachment during copulation
e) Interlocking of body parts

Figure 40 below illustrates 8 fundamental classes of fixation principles including hooks, lock or snap, clamp, spacer, sucker, expansion anchor, adhesive secretions, friction.

Figure 40 – Eight fundamental classes of fixation principles: hooks (A), lock or snap (B), clamp (C), spacer (D), sucker (E), expansion anchor (F), adhesive secretions (G), friction (H) (from Gorb p38)

Gorb concludes his description of the functions of hooks in insect species with the following description (p50):

“The hook mechanism is usually comprised of two complementary surfaces. These surfaces are not necessarily mirrored copies of each other but some dependence on the corresponding surface does exist. If both surfaces bear hooks (wing-interlock) their dimensions are usually predefined in order to optimise attachment and the probability of attachment as well. When only one surface bears real hooks, they could only attach efficiently to a particular range of textures (tarsal claws, hooks of phoretic and parasitic animals). The hook design can range from unicellular acanthi and multicellular setae to spines and cuticular folds.”

HOOKING TO THE SUBSTRATUM

This function is viewed in terms of claws to aid locomotion or to provide anchorage. For example in terrestrial locomotion the tarsal claw/s interlock with the surface textures to generate friction. Orb-web spiders have claws with a comb-like serrate bristle edge. This plays an important part in interlocking on the silk thread. Some butterfly pupae (e.g. Thyridopteryx ephemeraeformis, Lepidoptera, Psychidae) have hooks at their posterior end to anchor them inside their cocoon. Hooks are also used to attach material to an animal body (the crab Loxorhynchus crispatus decorates its shell by hooking with specialised setae).

ANIMAL ASSOCIATIONS: PHORESY, PARASITISM, PREDATION

Bird mites (Order Acari genus Michaelicus) parasite onto bird feathers. They have an asymmetric design of their legs with only one leg having a tarsus with a claw, which they feed through the barbules of the feathers to find anchorage. Hook-like devices are found only on mites parasitizing onto the stiff parts of the feather whereas mites that live on the soft parts of the feather use a clamping device.

Copepoda parasitica are parasitic copepod crustaceans with hooked appendages for attachment to host and some species of fish lice use hook-like appendages to attach themselves to their hosts.

HOOKING INTO BIOLOGICAL TISSUES

Gorb lists copepod crustaceans, ixodid ticks and dipteran insects as having mouthparts with hook-like structures for attachment to hosts. Also parasitic copepods such as Hatschekia pseudohippoglossi and Trebius clidodermi.

ATTACHMENT DURING COPULATION

Gorb adds the attachment structures of Harpocera thoracica to the organisms mentioned previously in section 2.2.2.
1.1.1.1 INTERLOCKING OF BODY PARTS

This category mainly includes wing-connectors. (Figure 41)

Figure 41 – Wing inter-lock devices in Heteroptera and Auchenorrhyncha (Gorb p45)

MECHANICAL PROPERTIES OF BIOLOGICAL MATERIALS: A BRIEF DISCUSSION OF THEIR ORIGINS IN BIOLOGICAL ATTACHMENT SYSTEMS

The mechanical properties of a biological material have their origins at molecular level.

Self-assembly is an area of study all of its own. From what I have gathered from the literature it is the process (or a portion of the process) by which biological materials grow. Molecules come together to form the required structures which develop into the forms and structures that make up the organism.

Currently, research into self-assembly has developed to the point where nacre can be manufactured (it is being developed for use in rocket exhaust nozzles for its insulating properties as a ceramic) but it has not led to the harvesting of free-standing structures possessing biomimetic properties See Benyus [‎5].

I discuss growth in relation to biological hooks in the final discussion and conclusions of this report.

The behaviour of a structure does not depend solely upon its shape and material strength; some structures in nature are actually made up of a single, small structure that is repeated many times. This has been described as a field of structures such as those used in probabilistic fasteners (see Section ‎2.3.3.5). These fields of structures can possess further behavioural properties deriving from their proximity to one another and their order of size magnitude which brings into play intra-molecular forces such as friction, charge and capillary action (surface tension) due to the presence of moisture.

The dragonfly head-arrestor mechanism as will be discussed in Case Study 2 is itself not a single structure that performs the attachment but instead a field of the structures that intermesh in a somewhat “unplanned” fashion. Its structures are not hooked, in fact they are flattened projections that use friction as a retaining force.

An overview of the biological material properties presents us with the conclusion that the overall behaviour of a structure is a summation of the properties of the component structures. And further, with regard to the small (micro and smaller) structures that many biological attachment mechanisms are, the resultant attachment force is the sum of component forces, sometimes with contributions from unexpected sources.

BIBLIOGRAPHY

1. “Insect Biology A Textbook of Entomology”, H E Evans, 1984, Addison-Wesley, ISBN 0-201-11981-1
2. “Plant form An Ilustrated guide to Flowering Plant Morphology”, A E Bell, 1991, Oxford University Press, ISBN 0-19-854219-4
3. “Biological Mechanisms of Attachment, The Comparative Morphology and Bioengineering of Organs for Linkage, Suction and Adhesion”, W Nachtigall, 1974 translated by M A Biederman-Thorson, Springer-Verlag, ISBN 3-540-06550-4
4. “Biomimicry Innovation Inspired by Nature” J M Benyus 1997, William Morrow and Company, ISBN 0-688-13691-5

IMAGE REFERENCES

I. http://www.aquaculturemag.com/siteenglish/printed/archives/issues03/03articles/HeckmanFeatureForWeb.pdf Argulus figure 2
II. http://www.mov.vic.gov.au/crust/barnbiol.html Acorn barnacle figure 3
III. http://www.enature.com/fieldguide/showSpecies_LI.asp?imageID=19348 Giant Acorn barnacle figure 4
IV. http://medent.usyd.edu.au/fact/birdmite.html figure 9
V. http://tolweb.org/tree?group=Abralia&contgroup=Enoploteuthidae figure 11
VI. http://tolweb.org/tree?group=Galiteuthis&contgroup=Cranchiidae figure 13

VII. http://www.nature.com/nsu/010823/010823-10.html
VIII. http://www.floridanature.org/species.asp?species=Apis_mellifera figure 20
IX. http://www.bioimages.org.uk/HTML/T1457.HTM shield bug figure 22
X. http://www.geocities.com/pelionature/Graphosoma_italicum2.htm figure 23
XI. http://www.insectimages.org/browse/family.cfm?id=Gerridae figure 25
XII. http://eny3005.ifas.ufl.edu/lab1/Homoptera/Homoptera.htm figure 26

XIII. http://www.lib.ncsu.edu/agnic/sys_entomology/taxon/raphidiodea/#order figure 27
XIV. http://bioweb.uwlax.edu/zoolab/Table_of_Contents/Lab-4a/Class_Monogenea/class_monogenea.htm figure 28
XV. http://www-biol.paisley.ac.uk/courses/Tatner/biomedia/pictures/fishl.htm figure 29
XVI. http://www.konig- photo.com/english/galerie/zoom.asp?pre=8206&NumPhoto=8207&suiv=8208&Rub=483 figure 30
XVII. http://www.hiltonpond.org/ThisWeek030308.html woodpecker tongue figure 31
XVIII. http://www.palmsoftheworld.com/plec.htm plectocomia himalayana figure 32
XIX. http://www.pharmakobotanik.de/systematik/7_bilder/yamasaki/Uncaria.jpg figure 33
XX. tapeworm
XXI. http://botanical.com/botanical/mgmh/b/burdoc87.html burdock figure 35
XXII. http://www.bioimages.org.uk/HTML/P146161.HTM agrimonia eupatoria figure 36
XXIII. http://plants.usda.gov/cgi_bin/large_image_rpt.cgi?imageID=gaap2_002_avp.tif galium figure 37
XXIV. http://www.inhs.uiuc.edu/chf/pub/surveyreports/nov-dec96/acanth.html acanthocephalan worm from rainbow trout figure 38

Biomimetics, Microscopy, Probablistic, Software (C++) and a Summing Up

Biomimetics, Microscopy, Probablistic, Software (C++) and a Summing Up.

Biomimetics, Microscopy, Probablistic, Software (C++) and a Summing Up

Biomimetics, Microscopy, Problablistic, Software (C++) and a Summing Up.

Of the Contents of my Blog in a small part, but the by far most popular.