|Shark & Remora
A remora sometimes called a suckerfish or sharksucker, is an elongated, brown fish in the order§ Perciformes and family Echeneidae. They grow to 30–90 centimetres long (1–3 ft), and their distinctive first dorsal fin takes the form of a modified oval sucker-like organ with slat-like structures that open and close to create suction and take a firm hold against the skin of larger marine animals. By sliding backward, the remora can increase the suction, or it can release itself by swimming forward. Remoras sometimes attach to small boats. They swim well on their own, with a sinuous, or curved, motion.
Remoras are primarily tropical open-ocean dwellers, occasionally found in temperate or coastal waters if they have attached to large fish that have wandered into these areas. In the mid-Atlantic, spawning usually takes place in June and July; in the Mediterranean, in August and September. The sucking disc begins to show when the young fish are about 1 centimetre long. When the remora reaches about 3 centimetres, the disc is fully formed and the remora is then able to hitch a ride. The remora's lower jaw projects beyond the upper, and there is no swim bladder.
Some remoras associate primarily with specific host species. Remoras are commonly found attached to sharks, manta rays, whales, turtles, and dugong (hence the common names sharksucker and whalesucker). Smaller remoras also fasten onto fish like tuna and swordfish, and some small remoras travel in the mouths or gills of large manta rays, ocean sunfish, swordfish, and sailfish.
The relationship between remoras and their perfect hosts is most often taken to be one of commensalism, specifically phoresy. The host they attach to for transport gains nothing from the relationship, but also loses little. The remora benefits by using the host as transport and protection and also feeds on materials dropped by the host. There is controversy whether a remora's diet is primarily leftover fragments, or the feces of the host. In some species (Echeneis naucrates and E. neucratoides) consumption of host feces is strongly indicated in gut dissections. For other species, such as those found in a host's mouth, scavenging of leftovers is more likely. For some remora and host pairings the relationship is closer to mutualism, with the remora cleaning bacteria and other parasites from the host.
Mistletoe & Hardwood Tree
Mistletoe is the common name for a group of hemi-parasitic plants in the order Santalales that grow attached to and within the branches of a tree or shrub. The name was originally applied to Viscum album (European Mistletoe, Santalaceae), the only species native in Great Britain and much of Europe. Later the name was further extended to other related species, including Phoradendron serotinum (the Eastern Mistletoe of eastern North America, also Santalaceae). European mistletoe, Viscum album is readily recognized by its smooth-edged oval evergreen leaves borne in pairs along the woody stem, and waxy white berries in dense clusters of 2 to 6. In America, the Eastern Mistletoe is similar, but has shorter, broader leaves and longer clusters of 10 or more berries.
Viscum album is a poisonous plant that causes acute gastrointestinal problems including stomach pain, and diarrhea along with low pulse. However, both European Mistletoe and the North American species, Phoradendron flavescens, are commercially harvested for Christmas decorations.
The largest family of Mistletoes, Loranthaceae, has 73 genera and over 900 species. Subtropical and tropical climates have markedly more Mistletoe species; Australia has 85, of which 71 are in Loranthaceae, and 14 in Santalaceae. Parasitism has evolved only nine times in the plant kingdom; of those, the parasitic mistletoe habit has evolved independently five times: Misodendraceae, Loranthaceae, and Santalaceae, including the former separate families Eremolepidaceae and Viscaceae. Although Viscaceae and Eremolepidaceae were placed in a broadly-defined Santalaceae by Angiosperm Phylogeny Group II, DNA data indicates that they evolved independently.
The word 'mistletoe' (Old English mistiltan) is of uncertain etymology; it may be related to German Mist, for dung and Tang for branch, since mistletoe can be spread in the feces of birds moving from tree to tree. However, Old English mistel was also used for basil. Mistletoe plants grow on a wide range of host trees, and commonly reduce their growth but can kill them with heavy infestation. Viscum album can parasitise more than 200 tree and shrub species. Almost all mistletoes are hemi-parasites, bearing evergreen leaves that do some photosynthesis, and using the host mainly for water and mineral nutrients. However, the mistletoe first sprouts from bird feces on the trunk of the tree and indeed in its early stages of life takes it nutrients from this source. An exception is the leafless quintral, Tristerix aphyllus, which lives deep inside the sugar-transporting tissue of a spiny cactus, appearing only to show its tubular red flowers. The genus Arceuthobium (dwarf mistletoe; Santalaceae) has reduced photosynthesis; as an adult, it manufactures only a small proportion of the sugars it needs from its own photosythesis but as a seedling it actively photosynthesizes until a connection to the host is established. Some species of the largest family, Loranthaceae, have small, insect-pollinated flowers (as with Santalaceae), but others have spectacularly showy, large, bird-pollinated flowers.
Most mistletoe seeds are spread by birds, such as the Mistle Thrush in Europe, the Phainopepla in southwestern North America, and Dicaeum of Asia and Australia. However, distinguishing between this species and ones of other ecological biomes is not difficult. They derive sustenance and agility through eating the fruits and nuts (drupes). The seeds are excreted in their droppings and stick to twigs, or more commonly the bird grips the fruit in its bill, squeezes the sticky coated seed out to the side, and then wipes its bill clean on a suitable branch. The seeds are coated with a sticky material called viscin (containing both cellulosic strands and mucopolysaccharides), which hardens and attaches the seed firmly to its future host.
Mistletoe was often considered a pest that kills trees and devalues natural habitats, but was recently recognized as an ecological keystone species, an organism that has a disproportionately pervasive influence over its community. A broad array of animals depend on mistletoe for food, consuming the leaves and young shoots, transferring pollen between plants, and dispersing the sticky seeds. The dense evergreen witches' brooms formed by the dwarf mistletoes (Arceuthobium species) of western North America also make excellent locations for roosting and nesting of the Northern Spotted Owls and the Marbled Murrelets. In Australia the Diamond Firetails and Painted Honeyeaters are recorded as nesting in different mistletoes. This behavior is probably far more widespread than currently recognized; more than 240 species of birds that nest in foliage in Australia have been recorded nesting in mistletoe, representing more than 75% of the resident avifauna.
A study of mistletoe in junipers concluded that more juniper berries sprout in stands where mistletoe is present, as the mistletoe attracts berry-eating birds which also eat juniper berries. Such interactions lead to dramatic influences on diversity, as areas with greater mistletoe densities support higher diversities of animals. Thus, rather than being a pest, mistletoe can have a positive effect on biodiversity, providing high quality food and habitat for a broad range of animals in forests and woodlands worldwide.
Bacteria & Termite Gut
Worker termites undertake the labors of foraging, food storage, brood and nest maintenance, and some defense duties in certain species. Workers are the main caste in the colony for the digestion of cellulose in food and are the most likely to be found in infested wood. This is achieved in one of two ways. In all termite families except the Termitidae, there are flagellate protists in the gut that assist in cellulose digestion. However, in the Termitidae, which account for approximately 60% of all termite species, the flagellates have been lost and this digestive role is taken up, in part, by a consortium of prokaryotic organisms. This simple story, which has been in entomology textbooks for decades, is complicated by the finding that all studied termites can produce their own cellulase enzymes, and therefore can digest wood in the absence of their symbiotic microbes. Our knowledge of the relationships between the microbial and termite parts of their digestion is still rudimentary. What is true in all termite species, however, is that the workers feed the other members of the colony with substances derived from the digestion of plant material, either from the mouth or anus. This process of feeding of one colony member by another is known as trophallaxis and is one of the keys to the success of the group. It frees the parents from feeding all but the first generation of offspring, allowing for the group to grow much larger and ensuring that the necessary gut bacteria are transferred from one generation to another. Some termite species do not have a true worker caste, instead relying on nymphs that perform the same work without moulting into a separate caste.
Termites are generally grouped according to their feeding behaviour. Thus, the commonly used general groupings are subterranean, soil-feeding, drywood, dampwood, and grass-eating. Of these, subterraneans and drywoods are primarily responsible for damage to human-made structures.
All termites eat cellulose in its various forms as plant fibre. Cellulose is a rich energy source (as demonstrated by the amount of energy released when wood is burned), but remains difficult to digest. Termites rely primarily upon symbiotic protozoa (metamonads) such as Trichonympha, and other microbes in their gut to digest the cellulose for them and absorb the end products for their own use. Gut protozoa, such as Trichonympha, in turn rely on symbiotic bacteria embedded on their surfaces to produce some of the necessary digestive enzymes. This relationship is one of the finest examples of mutualism among animals. Most so called "higher termites", especially in the Family Termitidae, can produce their own cellulase enzymes. However, they still retain a variety of gut bacteria and primarily rely upon the bacteria. Due to closely related bacterial species, it is strongly presumed that the termites' gut flora are descended from the gut flora of the ancestral wood-eating cockroaches, like those of the genus Cryptocercus.
Ants & Acacia Tree
Acacia cornigera, commonly known as Bullhorn Acacia (family Fabaceae), is a swollen-thorn acacia native to Mexico and Central America. The common name of "bullhorn" refers to the enlarged, hollowed-out, swollen thorns (technically called stipular spines) that occur in pairs at the base of leaves, and resemble the horns of a steer. In Yucatán (one region where the bullhorn acacia thrives) it is called "subín", in Panamá the locals call them "cachito" (little horn). The tree grows to a height of 10 metres (33 ft).
Bullhorn Acacia is best known for its symbiotic relationship with a species of Pseudomyrmex ant (Pseudomyrmex ferruginea) that lives in its hollowed-out thorns. Unlike other acacias, Bullhorn acacias are deficient in the bitter alkaloids usually located in the leaves that defend against ravaging insects and animals. Bullhorn acacia ants fulfill that role.
The ants act as a defense mechanism for the tree, protecting it against harmful insects, animals or humans that may come into contact with it. The ants live in the hollowed-out thorns for which the tree is named. In return, the tree supplies the ants with protein-lipid nodules called Beltian bodies from its leaflet tips and carbohydrate-rich nectar from glands on its leaf stalk. These Beltian bodies have no known function other than to provide food for the symbiotic ants. The aggressive ants release an alarm pheromone and rush out of their thorn "barracks" in great numbers.
According to Daniel Janzen (Costa Rican Natural History, 1983), livestock can apparently smell the pheromone and avoid these acacias day and night. Getting stung in the mouth and tongue is an effective deterrent to browsing on the tender foliage. In addition to protecting A. conigera from leaf-cutting ants and other unwanted herbivores, the ants also clear away invasive seedlings around the base of the tree that might overgrow it and block out vital sunlight.
Honeyguide bird & Badger
Honeyguides, (family Indicatoridae), are near passerine bird species of the order Piciformes. They are also known as indicator birds, or honey birds, although the latter term is also used more narrowly to refer to species of the genus Prodotiscus. They have an Old World tropical distribution, with the greatest number of species in Africa and two in Asia.
Honeyguides are noted and named for one or two species that will deliberately lead humans directly to bee colonies, so that they can feast on the grubs that are left behind.
Most honeyguides are dull-colored, though a few have bright yellow in the plumage. All have light outer tail feathers, which are white in all the African species.
They are among the few birds that feed regularly on wax—beeswax in most species, and presumably the waxy secretions of scale insects in the genus Prodotiscus and to a lesser extent in Melignomon and the smaller species of Indicator. They also feed on the larvae and on waxworms (caterpillars of Galleria mellonella) in bee colonies, and on flying and crawling insects, spiders, and occasional fruits. Many species join mixed-species feeding flocks.
Honeyguides are named for a remarkable habit seen in one or two species: they guide humans, and possibly other large mammals (such as the Honey Badger) to bee colonies. Once the mammal opens the hive and takes the honey, the bird feeds on the remaining wax and larvae. This behavior is well studied in the Greater Honeyguide; some authorities (following Friedmann, 1955) state that it also occurs in the Scaly-throated Honeyguide, while others disagree (Short and Horne, 2002). One researcher found use of honeyguides by the Boran people of East Africa reduces the search time of people for honey by approximately two-thirds. Because of this benefit, the Boran use a specific loud whistle, known as the "Fuulido", when a search for honey is about to begin. The "Fuulido" doubles the encounter rate with honeyguides.
Although most members of the family are not known to recruit "followers" in their quest for wax, they are also referred to as "honeyguides" by linguistic extrapolation.
The breeding behavior of eight species in Indicator and Prodotiscus is known. They are all brood parasites that lay one egg in a nest of another species, laying eggs in series of about five during five to seven days. Most favor hole-nesting species, often the related barbets and woodpeckers, but Prodotiscus parasitizes cup-nesters such as white-eyes and warblers. Honeyguide nestlings have been known to physically eject their host's chicks from the nest and they have hooks on their beaks with which they puncture the hosts' eggs or kill the nestlings.
Shrimp & Goby Fish
The gobies form the family Gobiidae, which is one of the largest families of fish, with more than 2,000 species in more than 200 genera. Most are relatively small, typically less than 10 cm (4 in) in length. Gobies include some of the smallest vertebrates in the world, like species of the genera Trimmaton and Pandaka, which are under 1 cm (3/8 in) long when fully grown. There are some large gobies, such as some species of the genera Gobioides or Periophthalmodon, that can reach over 30 cm (1 ft) in length, but that is exceptional. Although few are important as food for humans, they are of great significance as prey species for commercially important fish like cod, haddock, sea bass, and flatfish. Several gobies are also of interest as aquarium fish, such as the bumblebee gobies of the genus Brachygobius.
The most distinctive aspects of goby morphology are the fused pelvic fins that form a disc-shaped sucker. This sucker is functionally analogous to the dorsal fin sucker possessed by the remoras or the pelvic fin sucker of the lumpsuckers, but is anatomically distinct: these similarities are the product of convergent evolution. Gobies can often be seen using the sucker to adhere to rocks and corals, and in aquariums they will happily stick to glass walls of the tank, as well.
Gobies are primarily fish of shallow marine habitats including tide pools, coral reefs, and seagrass meadows; they are also very numerous in brackish water and estuarine habitats, including the lower reaches of rivers, mangrove swamps, and salt marshes. A small number of gobies (unknown exactly, but in the low hundreds) are also fully adapted to freshwater environments. These include the Asian river gobies (Rhinogobius spp.), the Australian desert goby (Chlamydogobius eremius), and the European freshwater goby Padogobius bonelli. Most gobies feed on small invertebrates, although some of the larger species eat other fish, and a few eat planktic algae.
Gobies in warmer waters reach adulthood in a matter of months, while those in cooler environments may take up to two years. The total lifespan of gobies varies from a single year to up to ten years, again with the temperate species generally living longer.
A few species of goby are known to be able to change sex from female to male, although most do not do this. In such species, most individuals are born female, and the male must expend considerable effort in guarding the eggs of the multiple females with which he breeds.
Some marine gobies live in symbiosis with a shrimp. Gobies sometimes form symbiotic relationships with other species. Some goby species live in symbiosis with burrowing shrimps. The shrimp maintains a burrow in the sand in which both the shrimp and the goby live. The shrimp has poor eyesight compared to the goby, but if it sees or feels the goby suddenly swim into the burrow, it will follow. The goby and shrimp keep in contact with each other, the shrimp using its antennae, and the goby flicking the shrimp with its tail when alarmed. These gobies are thus sometimes known as watchmen or prawn gobies. Each party gains from this relationship: the shrimp gets a warning of approaching danger, and the goby gets a safe home and a place to lay its eggs. Only the alpha male and female reproduce, other fish in colony eat sparingly to resist being eaten by the alpha male or female. This way only the largest and fittest are able to reproduce.
Another example of symbiosis is demonstrated by the neon gobies (Elacatinus spp.). These gobies are known as "cleaner gobies", and remove parasites from the skin, fins, mouth, and gills of a wide variety of large fish. The most remarkable aspect of this symbiosis is that many of the fish that visit the gobies' cleaning stations would otherwise treat such small fish as food (for example, groupers and snapper[disambiguation needed]s). Again, this is a relationship where both parties gain: the gobies get a continual supply of food as bigger fish visit their cleaning stations, and the bigger fish leave the cleaning stations healthier than they were when they arrived.
Leafhopper & Meat Ant
Meat ants (Iridomyrmex purpureus), also known as meat-eater ants or gravel ants, are a species of ant belonging to the Iridomyrmex genus. They can be found throughout Australia.
Meat ants live in underground nests of up to 64,000 ants. Many nests may be connected together into a supercolony that stretches up to 650 metres (0.4 miles). Nest holes are regularly arranged, and each leads to a separate series of branched tunnels, which typically do not connect with the tunnels from other holes. Satellite colonies are commonly formed by reproductively active daughter queens near the main nest, usually around five to ten metres away, sometimes as much as 50 metres.
The use of different parts of the nests is largely dependant on environmental factors, for example excessive shading of the main mound will stimulate the occupation of different parts of the nest or the expansion of satellite colonies. Meat ants cover their nest mounds with gravel, sand, leaf petioles, twigs, seed capsules, mollusk shells and other small items, which heat the nest quicker in the morning.
Leafhoppers excrete sugary sap that is collected by meat ants, which protect this valuable food resource
Meat ants are omnivorous scavengers that get their name from their use, by farmers, to clean carcasses. Meat ants are diurnal, their foraging is dependent on ambient temperature. On hot days foraging is bimodal, with all activity ceasing during the heat of the day.
Like other Iridomyrmex species, they engage in a mutualistic relationship with certain caterpillars and butterflies of specific species which produce secretions that meat ants will feed on. In return, they protect the caterpillars from predation. Honeydew collected from hemipterous insects is the main component of the diet of most meat ant colonies. This is supplemented by scavenging for dead invertebrates.
Bobtail Squid & Bioluminescent Bacteria
Bobtail squid (order Sepiolida) are a group of cephalopods closely related to cuttlefish. Bobtail squid tend to have a rounder mantle than cuttlefish and have no cuttlebone. They have eight suckered arms and two tentacles and are generally quite small (typical male mantle length being between 1 and 8 cm). Sepiolids live in shallow coastal waters of the Pacific Ocean and some parts of the Indian Ocean as well as in shallow waters on the west coast of the Cape Peninsula off South Africa. Like cuttlefish, they can swim by either using the fins on their mantle or by jet propulsion. They are also known as dumpling squid (owing to their rounded mantle) or stubby squid.
Bobtail squid have a symbiotic relationship with bioluminescent bacteria (Vibrio fischeri), which inhabit a special light organ in the squid's mantle. The bacteria are fed a sugar and amino acid solution by the squid and in return hide the squid's silhouette when viewed from below by matching the amount of light hitting the top of the mantle. The organ contains filters which may alter the wavelength of luminescence closer to that of downwelling moonlight and starlight; a lens with biochemical similarities to the squid's eye to diffuse the bacterial luminescence; and a reflector which directs the light ventrally.
Sepiolida are iteroparous and a female might lay several clutches, each of 1-400 eggs (dependent on species), over her estimated one year long lifetime. The eggs are covered with sand and left without parental care. Symbiosis with V. fischeri from the surrounding seawater is initiated immediately upon hatching, and the bacteria's colonisation of the juvenile light-organ induces morphological changes in the squid that lead to maturity.
Corals & Zooxanthella
Zooxanthellae (plural, pronounced /ˌzoʊ.əzænˈθɛliː/) are flagellate protozoa that are golden-brown intracellular endosymbionts of various marine animals and protozoa, especially anthozoans such as the scleractinian corals and the tropical sea anemone, Aiptasia.
Zooxanthellae live in other protozoa (foraminiferans and radiolarians) and in some invertebrates. Most are autotrophs and provide the host with energy in the form of translocated reduced carbon compounds, such as glucose, glycerol, and amino acids, which are the products of photosynthesis . Zooxanthellae can provide up to 90% of a coral’s energy requirements. In return, the coral provides the zooxanthellae with protection, shelter, nutrients (mostly waste material containing nitrogen and phosphorus) and a constant supply of carbon dioxide required for photosynthesis. Available nutrients, incident light, and expulsion of excess cells limits their population.