GRIBBLE

A gribble /ˈgɹɪbəl/ (or gribble worm) is any of about 56 species of marine isopod from the family Limnoriidae. They are mostly pale white and small (1–4 millimetres or 0.04–0.16 inches long) crustaceans, although Limnoria stephenseni from subantarctic waters can reach 10 mm (0.4 in).

Limnoria quadripunctata
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Subphylum:	Crustacea
Class:	Malacostraca
Order:	Isopoda
Suborder:	Limnoriidea
Family:	Limnoriidae White, 1850

Classification

The term "gribble" was originally assigned to the wood-boring species, especially the first species described from Norway by Jens Rathke in 1799, Limnoria lignorum. The Limnoriidae are now known to include seaweed and seagrass borers, as well as wood borers. Those gribbles able to bore into living marine plants are thought to have evolved from a wood (dead plant) boring species.

Ecology

Gribbles bore into wood and plant material for ingestion as food. The cellulose of wood is digested, most likely with the aid of cellulase produced by the gribbles themselves. The most destructive species are Limnoria lignorum, L. tripunctata and L. quadripunctata. Due to dispersal while inhabiting wooden ships, it is uncertain where these three mentioned species originated. Limnoriidae are second only to the Teredinidae in the amount of destruction caused to marine timber structures such as jetties and piers. L. tripunctata is unusually tolerant of creosote, a preservative often used to protect timber piles, due to symbiosis with creosote-degrading bacteria. Gribbles bore the surface layers of wood, unlike the Teredinidae which attack more deeply. Their burrows are 1–2 mm diameter, may be several centimetres long, and have the burrow’s roof punctured with a series of smaller ventilation holes. Attacked wood can become spongy and friable.

Gribbles play an ecologically important role, by helping to degrade and recycle driftwood. Most seaweed boring gribbles attack holdfasts and their activities can cause the seaweed to come adrift especially during storms.

For defence, gribbles can jam themselves within their burrows using their uropods and block the tunnel with their rear disc-shaped segment, the pleotelson.

A number of crustaceans have evolved as commensals with Limnoriidae. Chelura are amphipods that inhabit the more severely attacked regions of gribble-attacked wood. Donsiellaare tiny copepods that inhabit the brood pouch and body of Limnoriidae.

As Source of Biofuel

It has been suggested that the enzymes used by Limnoriidae to break down wood may be useful for producing sugar from non-food biomass, such as wood or straw, in a sustainable way. This could then be used to produce alternative fuels. Enzymes produced by the tiny creatures are able to break down woody cellulose and turn it into energy-rich sugars meaning that gribble could convert wood and straw into liquid biofuel." One particular enzyme produced in a special organ in the body of the gribble called the hepatopancreas and secreted into its gut has recently been identified and characterized: the GH7 cellobiohydrolase. LqCel7B. This enzyme has been shown to be highly effective in a salty environment such as that in which the gribble lives.

References

Notes

1. ^ WoRMS (2011). M. Schotte, C. B. Boyko, N. L. Bruce, G. C. B. Poore, S. Taiti & G. D. F. Wilson, ed. "Limnoriidae". World Marine, Freshwater and Terrestrial Isopod Crustaceans database. World Register of Marine Species. Retrieved December 1, 2011.
2. ^ GRIBBLE VERSUS GRIBBLE – LET WORM BATTLE COMMENCE.
3. ^ Damage to wooden slipway following gribble activity.
4. ^ "Sailors’ historic scourge may hold the key to bioenergy future". University of York. January 27, 2009.
5. ^ "'Gribble' marine pest may be key to biofuel breakthrough, say scientists. The Times. March 9, 2010.
6. ^ "Structural characterization of a unique marine animal family 7 cellobiohydrolase suggests a mechanism of cellulase salt tolerance", Kern et al, PNAS June 3, 2013

Bibliography

• R. J. Menzies. The marine borer family Limnoriidae (Crustacea, Isopoda). Bulletin of Marine Science of the Gulf and Caribbean. 1957 7: 101–200.
• L. J. Cookson. Australasian species of the Limnoriidae (Crustacea: Isopoda). Memoirs of the Museum of Victoria 1991 52: 137–262.
• L. J. Cookson and G. C. B. Poore. New species of Lynseia and transfer of the genus to Limnoriidae (Crustacea: Isopoda). Memoirs of the Museum of Victoria 1994 54: 179–189.

- Wikipedia 

PANAQUE

The genus Panaque contains a small number of small to medium sized South American suckermouth armoured catfishes that are notable for being among the very few vertebrates that feed extensively onwood . In addition, algae and aufwuchs are an important part of the diet, and they use their rasping teeth to scrape this from rocks. These fish are also popular aquarium fish, where the sound of scraping as these fish forage for food is easily audible.

Panaque nigrolineatus in an aquarium
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Siluriformes
Family:	Loricariidae
Subfamily:	Hypostominae
Tribe:	Ancistrini
Genus:	Panaque C. H. Eigenmann & R. S. Eigenmann, 1889

Taxonomy

Scobinancistrus and Panaqolus, are sometimes considered to be subgenera of this genus.

Specices

There are currently seven recognized species in this genus:

• Panaque armbrusteri Lujan Hidalgo & D. J. Stewart, 2010.
• Panaque bathyphilus Lujan, & Chamon, 2008
• Panaque cochliodon, Steindachner, 1879
• Panaque nigrolineatus W. K. H. Peters1877 (Royal panaque)
• Panaque schaeferiLujan Hidalgo & D. J. Stewart, 2010
• Panaque suttonorum, L.P. Schultz 1944 (Blue-eye panaque)
• Panaque titan Lujan, Hidalgo & D. J. Stewart, 2010

Etymology

The name Panaque is a Latinisation of a native Venezuelan name for these fish. It is pronounced "pan ack" in Britain and Europe, but often as "pan aki" or "pan a kay" in America. The Japanese call these fish "pana koo ee".

Distribution and Habitat

Panaque are found in the Magdalena River, Orinoco River, Amazon River, Essequibo River, and Lake Maracaibo drainages. All Panaque come from tropical South American and inhabit fast-flowing streams and rivers. They are weak swimmers but like other armoured catfish possess a strong sucker-like mouth with which they can hold on to submerged rocks and wood.

Physical Characteristics

Like other members of the armoured catfish family (Loricariidae), all Panaque have sturdy, armoured bodies covered in toughened plates of skin called scutes. These are not scales; like all catfish, Panaque lack scales. As well their armour, these catfish have very sturdy dorsal and pectoral fin spines. They use these defensively, either to wedge themselves into cracks from which predators cannot pull them, or else to prevent large predators from swallowing them. Another characteristic typical of the armoured catfish family is an iris. Most fish are unable to regulate the amount of light that enters the eye since they have irises that cannot change size. Both male and female Panaque develop bristles, known as odontodes, on the side of head immediately before and onto the pectoral fins.

Mouth and teeth of Panaque nigrolineatus

Unlike predatory catfish, these omnivorous catfish have very short barbels. These barbels can be seen in the photograph of mouth of a Panaque shown here; they are the short pointed structures on either side of a suckermouth. This sucker-like mouth allows them to attach to rocks and remain stationary with very little expenditure of energy.

Xylophagy  ( Wood Consumtion and Digestion)

Along with the species of the Hypostomus cochliodon group (formerly the genus Cochliodon), it has been argued that Panaque are the only fish that can eat and digest wood. Possible adaptations to consuming wood include spoon-shaped, scraper-like teeth and highly angled jaws to chisel wood. Researchers have also identified symbiotic gut bacteria that may allow the fish to digest the wood they consume. However, others have argued that Panaque do not in fact digest wood, and in fact take up very little energy from the wood they consume and actually lose weight when fed just wood. Furthermore, their digestive tracts are no different from those of related catfish and they do not hold wood particles in the gut longer than other catfish, suggesting Panaque are not physically adapted to eating wood, and are in fact detritivores much like other Loricariidae. In September 2010 scientists from the US National Science Foundation claimed to have discovered a new species of wood-eating catfish in the Alto Purús National Park, Peru.

In The Aquarium

Several species of Panaque have become popular aquarium fish, in particular the brightly coloured Panaque nigrolineatus. This fish is known as the "royal panaque" or "royal plec", a reflection of its costliness and beauty when compared with the common plecs, Hypostomusspp. widely sold to aquarists as algae eaters. Royal plecs have a greyish-green background colour against which are set thick, dark bluish-black stripes. The fins are edged with gold or cream, and the eyes are red. In captivity, royal plecs typically grow to around 30 cm in length.

A second species, Panaque cochliodon, is familiar to many aquarists as the blue-eyed plec. This fish was quite widely traded in the late 1980s and early 1990s but is now only rarely exported from its native Colombia. Aquarium books often refer to the blue-eyed plec as Panaque suttonorum or Panaque suttoni, though Panaque suttonorum is in fact a quite different fish that only comes from Venezuela. Blue-eyed plecs reach a similar size to royal plecs, but because many specimens are infected with a bacterium closely related to Rickettsia, mortality immediately after import can be high. Once settled in and feeding, they are no more difficult to keep than royal plecs.

All Panaque catfish require much the same thing in captivity. Their main demand is for a mixed diet including green algae, fresh vegetables such as carrots, courgettes, and spinach, and clean bogwood. In the wild, these fish feed almost entirely on wood and algae, and the meaty foods enjoyed by other plecs are not required. Because they are relatively large for aquarium fish and produce an unusual amount of waste, a big tank with a good filter is essential. Royal panaques at least are adaptable as far as water chemistry goes and though they prefer somewhat soft, slightly acid water conditions they will tolerate hard, alkaline water as well.

In terms of behaviour, Panaque are peaceful and nocturnal, and make good residents in community tanks. Like most of the other armoured catfish, they are territorial, and groups should only be kept in very large tanks.

References

1.  Panaque respirometry paper.
2. ^ Armbruster, Jon. "Panaque". Retrieved 2007-03-31.
3. ^ Froese, Rainer, and Daniel Pauly, eds. (2011). Species of Panaque, in FishBase. December 2011 version.
4. ^ ^a b c Revision of Panaque (Panaque), with Descriptions of Three New Species from the Amazon Basin (Siluriformes, Loricariidae) - bioone.org Retrieved 2011-01-03
5. ^ ^a b c Chockley, Brandon R.; Armbruster, Jonathan W. (May 2002). "Panaque changae, a new species of catfish (Siluriformes: Loricariidae) from eastern Peru, (PDF). Ichthyol. Explor. Freshwaters 13 (1): 81–90. Retrieved 2009-06-24.
6. ^ Nelson, J. A.; Wubah, D. A.; Whitmer, M. E.; Johnson, E. A.; Stewart, D. J. (1999). "Wood-eating catfishes of the genus Panaque: gut microflora and cellulolytic enzyme activities" (PDF). Journal of Fish Biology 54 (5): 1069–1082. doi:10.1111/j.1095-8649.1999.tb00858.x.
7. ^ ^a b German, D. P. (2009). "Inside the guts of wood-eating catfishes: can they digest wood?"(PDF). Journal of Comparative Physiology B 179 (8): 1011. doi:10.1007/s00360-009-0381-1.
8. ^ Govan, Fiona (2010-09-14). "Wood-eating catfish discovered in Peru", London: The Daily Telegraph, UK. Retrieved September 15, 2010.
9. ^ "PlanetCatfish::Catfish of the Month::May 1999. 2007-05-22. Retrieved 2007-07-01.
10. ^ PlanetCatfish • Frequently Asked Question.
11. ^ Khoo, L.; Dennis, P. M.; Lewbart, G. A. (1995). "Rickettsia-like organisms in the blue-eyed plecostomus, Panaque suttoni (Eigenmann & Eigenmann)". Journal of Fish Diseases 18(2): 157–164. doi:10.1111/j.1365-2761.1995.tb00273.x.

External Links

• Froese, Rainer, and Daniel Pauly, eds. (2006). Species of Panaque, in FishBase. May 2006 version.
• Panaque Research, Studies on the wood eating loricariid catfishes

- Wikipedia 

HORNTAIL

Horntail or wood wasp is the common name for any of the 150 non-social species of the family Siricidae, of the order Hymenoptera, a type of xylophagous sawfly. This family was, until recently, believed to be the sole living representative of the superfamily Siricoidea, a group well represented in Paleogene and Mesozoic times, but the family Anaxyelidae has recently been linked to this group. The last tergite of the abdomen has a strong, projecting spike, thus giving the group its common name (the ovipositor is typically longer and also projects posteriorly, but it is not the source of the name). A typical adult horntail is brown, blue, or black with yellow parts, and may often reach up to 4 cm long. The pigeon horntail (Tremex columba) can grow up to 5 cm long (not counting the ovipositor), among the longest of all Hymenoptera.

Horntail, as seen at Elephant Head Lake, Labrador, Canada
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Suborder:	Symphyta
Superfamily:	Siricoidea
Family:	Siricidae

Female horntails lay their eggs in trees. The larvae bore into the wood and live in the tree for up to two years, possibly more. They typically migrate to just under the bark before pupation.

The spiral groove on the ovipositor is visible on the photograph but not easily to the naked eye.

Description

The smaller horntail (Sirex noctilio) is only about half the size of the greater horntail, with pale brown legs and the rest metallic blue-black. It pierces the bark of pines to lay eggs. The smaller horntail ovipositor is very similar to the greater horntail, which is described as:

Sirex woodwasp (Sirex noctilio) from New Zealand, on Pinus radiata

“as stiff and straight as a needle, polished black, with slight notches in the pointed half. It is hinged, to permit of its being turned at right angles to the body. . . the female selects a tree that is not too healthy, and settles on the bole; then, turning down her boring instrument on its hinge, she drives it through the thick bark to the solid wood."

When we consider the small size of the insect, it seems remarkable that she should have muscular power sufficient to force that slight auger through such resistant material; but that the boring imposes no strain upon her is shown by the fact that she may make several experimental punctures without an egg passing; apparently the wood reached is not quite suited for her purpose, so she tries another spot. Often her operations are upon a tree that has been felled for the builder's use; and by this means the new generation finds its way at times into our homes. Having satisfied herself that at last she has found the proper conditions under which a larva could exist, she passes an egg into the wood; then she repeats the process at some other spot on the same tree or log.

Giant horntail (Urocerus gigas)

Members of 3 genera of horntail Siricidae attack dying or recently killed balsam fir and spruce  (Rose and Lindquist 1985). The common name derives from the stout, spine-like structure at the end of the adult’s body, which is used to pierce the host’s bark to allow the eggs to be inserted into the wood. Populations increase rapidly only where brood material is abundant. The life cycle usually requires 2 years, and the adults are usually in flight from late July to early September. Full-grown larvae may be up to 215 mm long. Wood-rotting fungi found in horntail tunnels cause very rapid deterioration of the wood and quickly reduce opportunities for salvage. A wasp-like parasite can detect the presence of a horntail larva tunnelling in the wood and then insert its ovipositor, a sheathed hair-like structure up to 10 cm long, through bark and wood into the tunnel to deposit an egg, the resulting larva from which feeds on the horntail larva.

Reproduction

Mr. K. G. Blair has given an interesting account of the proceedings of a female he watched on a felled larch, in which, when discovered, she had her ovipositor embedded deeply; but it was soon withdrawn. "The insect then wandered off, walking rather jerkily over the log, the ovipositor held in its sheath beneath the body, its tip dragging along the bark behind her. As she went her antennae were in constant action, tapping the bark in front of her. About six inches from the spot where we first found her, having apparently discovered another position to her liking, the body was raised as high as possible on her legs, the ovipositor slipped from its sheath and the point inserted in the bark beneath the middle of her body, i.e. some distance, about an inch, away from the spot last explored by her antennae. The ovipositor was then perpendicular to the bark and to the general axis of her body, though this was now somewhat arched, while its sheath remained in its original position. Gradually the ovipositor was driven farther into the log, a slight side-to-side motion of the body being perceptible, until finally it was buried almost to its full length. Though we watched carefully, we saw no sign of the passage of any egg down the ovipositor, but after a few seconds it was seen to be being slowly withdrawn, the withdrawal being considerably more rapid than the entry.From first point of insertion to complete withdrawal occupied ten minutes. The insect then moved off again, but once more the ovipositor was slipped from its sheath and driven for its full length into the wood ; in this case the operation taking a little longer, twelve minutes until complete withdrawal.... Again the insect moved off, the ovipositor dragging along behind her. The terminal spike of the body is not brought into play at all, either when walking over the surface or during the thrusting in of the ovipositor ; neither does the ovipositor sheath appear to afford any support during this operation. This time she wandered further without finding a suitable spot, then suddenly flew away." It has been stated that she lays about a hundred eggs; but Mr. Blair's account may modify this estimate—a boring not being always an egg-laying."

Growth of the egg

The right conditions having been found and an egg discharged through the boring instrument, from this in due course issues a six-legged, whitish larva, which sets to work with capable jaws on the solid wood, beginning the excavation of a long tunnel that will occupy several years before the larva is full-grown. That stage reached, it spins a silken cocoon, and changes into a pupa which has all its limbs of maturity formed and folded beside its body.

Before making its cocoon, however, it takes the precautionary measure of advancing its tunnel close up to the inner bark, so that in its winged state it will have only to bite a way through this softer impediment to its liberty; not that it is now incapable of dealing with anything firmer. Like the notorious caterpillar of the Goat-moth, it does not hesitate, if necessary, to make a way even through soft metal. There is a record of a Sirex-infested tree having been cut into rafters which were used in building a roof and covered with sheet-lead an eighth of an inch thick. One of the rafters contained a Sirex in either the larval or pupal stage; and when the perfect insect sought its freedom, it found the way obstructed by the lead. It went right through, apparently finding lead not much more difficult to deal with than bark. Other similar cases might be cited. It is not improbable that many specimens that issue in houses have been imported in building timber from abroad.’ ”

It adds that an ichneumon wasp (Rhyssa persuasoria) lays parasitic grubs in Sirex, which kill them.

Technological Inspiration

The female wood wasp lays eggs inside trees, and its methods of doing so have inspired scientists to come up with new and safer surgical probes that are said to be more efficient.

The wood wasp ovipositor contains two interlocking valves. Each valve is covered with teeth that are backward-facing. While the teeth of one valve catch onto the wood to provide resistance, the other valve moves forward taking a slight step. Then that valve catches the wood to provide resistance while the first valve moves forward. Thus by quick oscillation, the valves alternate in providing resistance and moving forward. This process leads in the ovipositor drilling almost an inch into the sapwood. The force used for this process is minimal. Buckling or breaking does not take place during the process.

Researchers and scientists have been inspired by the ovipositor of the female wood wasp. They have created a prototype neurosurgical probe that works on the same principle. Its needle is silicon. It has two valves that oscillate. Each of these valves has teeth that are micro-sized. This enables it to penetrate deep into the brain causing little damage. According to the New Scientist magazine, “Unlike existing rigid surgical probes, the device will be flexible enough to move along the safest possible route, bypassing high-risk area of the brain during surgery, for example”. A probe like this would considerably reduce the number of incisions necessary to access areas that are difficult to reach.

References

1. Bees, Wasps, Ants and Allied Insects of the British Isles, Edward Step (1932)
2. ^ Rose, A.H.; Lindquist, O.H. 1985. Insects of eastern spruces, fir and, hemlock, revised edition. Gov’t Can., Can. For. Serv., Ottawa, For. Tech. Rep. 23. 159 p. (cited in Coates et al. 1994, cited orig ed 1977).
3. ^ Ostrovsky, Gene. "Wood boring wasps inspire new neorosurg probe".  Retrieved 10 May 2012.
4. ^ Richards, Guy. "Wasps play part in surgical probe. Materials Worlds Magazine. Retrieved 10 May 2012.

- Wikipedia