Do bees use magnetoreception?
Schwarziana quadripunctata
This notion of magnetic navigational skills was first observed in a 2005 study conducted by Esquivel et al. on a "S. quadripunctata" nest near Rio de Janeiro, Brazil. The study applied various levels of applied magnetic fields across the entrance of the nest. The exiting angles (both vertical and horizontal) of the individual bees were then measured as they emerged from the nest. The primary control experiment confirmed that the majority of the nest had a preferential exiting angle in accordance with the local geomagnetic field. Over the course of four months, the study group measured the two angles in comparison to various magnitudes of applied magnetic fields and compared them to observed angles in natural geomagnetic fields. A significant correlation was found between the two, definitively showing that the stingless bee relies on magnetoreception for navigational purposes.
Bird vision
The perception of magnetic fields by migratory birds has been suggested to be light dependent. Birds move their head to detect the orientation of the magnetic field, and studies on the neural pathways have suggested that birds may be able to "see" the magnetic fields. The right eye of a migratory bird contains photoreceptive proteins called cryptochromes. Light excites these molecules to produce unpaired electrons that interact with the Earth's magnetic field, thus providing directional information.
Bumblebee
Bees beat their wings about 200 times a second. Their thorax muscles do not contract on each nerve firing, but rather vibrate like a plucked rubber band. This is efficient, since it lets the system consisting of muscle and wing operate at its resonant frequency, leading to low energy consumption. Further, it is necessary, since insect motor nerves generally cannot fire 200 times per second. These types of muscles are called asynchronous muscles and are found in the insect wing systems in families such as Hymenoptera, Diptera, Coleoptera, and Hemiptera. Bumblebees must warm up their bodies considerably to get airborne at low ambient temperatures. Bumblebees can reach an internal thoracic temperature of 30 °C (86 °F) using this method.
Magnetoreception
Magnetoreception (also magnetoception) is a sense which allows an organism to detect a magnetic field to perceive direction, altitude or location. This sensory modality is used by a range of animals for orientation and navigation, and as a method for animals to develop regional maps. For the purpose of navigation, magnetoreception deals with the detection of the Earth's magnetic field.
Palynivore
Bees, part of the superfamily Apoidea, engage in palynivory extensively, especially in providing pollen for their offspring. To effectively collect, transport, and consume pollen, bees have evolved specialized morphological and behavioral traits. To forage for pollen, bees must first find sources of pollen, which they do so through chemical, visual, and tactile signals given by flowers that have co-evolved adaptations for this purpose, since most flowering plants benefit from the pollination that occurs while bees collect and transport pollen. Visual signals especially help guide bees to flowers. With sight adaptations such as the ability to see ultraviolet light, bees hone in on the color pattern "targets" of flower petals that guide bees to nectar and pollen. They gather and store pollen together with nectar on specialized hairs and evolved scopal or corbicular constructions on their bodies. Bees have also evolved behavioral adaptations that involve some degree of learning. Most bees are also either oligolectic or polylectic, where they target specific or more general groups of flowering plants respectively, and their foraging patterns overlap significantly closely during the day and/or seasonally to the bloom periods of these targeted flowers. In the nest, bees will also communicate the locations of good foraging patches to other worker bees in a process called a waggle dance. Bees often favor certain foraging patches, and while evidence shows that bumblebees for instance are flexible in their foraging patterns, deciding on different types of flowers based on the pollen's protein:lipid ratios, these patterns directly influence the genetics of the flowering plant populations around them.
Magnetoreception
Then there is the distinction of magnetic usage. Some species may only be able to sense a magnetic compass to find north and south, while others may only be able to discern between the equator and the pole. Although the ability to sense direction is important in migratory navigation, many animals also have the ability to sense small fluctuations in earth’s magnetic field to compute coordinate maps with a resolution of a few kilometers or better. For a magnetic map, the receptor system would have to be able to discern tiny differences in the surrounding magnetic field to develop a sufficiently detailed magnetic map. This is not out of the question, as many animals have the ability to sense small fluctuations in the earth's magnetic field. This is not out of the question biologically, but physically has yet to be explained. For example, birds such as the homing pigeon are believed to use the magnetite in their beaks to detect magnetic signposts and thus, the magnetic sense they gain from this pathway is a possible map. Yet, it has also been suggested that homing pigeons and other birds use the visually mediated cryptochrome receptor as a compass.
Immunoprecipitation
While the vast majority of immunoprecipitations are performed with agarose beads, the use of superparamagnetic beads for immunoprecipitation is a much newer approach that is only recently gaining in popularity as an alternative to agarose beads for IP applications. Unlike agarose, magnetic beads are solid and can be spherical, depending on the type of bead, and antibody binding is limited to the surface of each bead. While these beads do not have the advantage of a porous center to increase the binding capacity, magnetic beads are significantly smaller than agarose beads (1 to 4μm), and the greater number of magnetic beads per volume than agarose beads collectively gives magnetic beads an effective surface area-to-volume ratio for optimum antibody binding.
Magnetotactic bacteria
Magnetotactic bacteria (or MTB) are a polyphyletic group of bacteria that orient themselves along the magnetic field lines of Earth's magnetic field. Discovered in 1963 by Salvatore Bellini and rediscovered in 1975 by Richard Blakmore, this alignment is believed to aid these organisms in reaching regions of optimal oxygen concentration. To perform this task, these bacteria have organelles called magnetosomes that contain magnetic crystals. The biological phenomenon of microorganisms tending to move in response to the environment's magnetic characteristics is known as magnetotaxis. (However, this term is misleading in that every other application of the term taxis involves a stimulus-response mechanism.) In contrast to the magnetoreception of animals, the bacteria contain fixed magnets that force the bacteria into alignment—even dead cells are dragged into alignment, just like a compass needle.
Magnetofossil
Within the magnetotactic bacteria, magnetite and greigite crystals are biosynthesized (biomineralized) within organelles called magnetosomes. These magnetosomes form chains within the bacterial cell and in doing so, provide the organism with a permanent magnetic dipole. The organism uses it for geomagnetic navigation, to align itself with the Earth's geomagnetic field (magnetotaxis) and to reach the optimal position along vertical chemical gradients.
Magnetoreception
In similar fashion, European ("Bufo bufo") and Natterjack ("Epidalea calamita)" toads appear to rely, at least somewhat, on magnetic information for certain orienting behaviours. These species of anurans are known to rely on vision and olfaction when locating and migrating to breeding sites, but it seems magnetic fields may also play a role. When randomly displaced from their breeding sites, these toads remain well-oriented, and are capable of navigating their way back, even when displaced by more than 150 meters. However, when this displacement is accompanied by the experimental attachment of small magnetic bars, toads fail to relocate breeding sites. Considering experimental attachment of non-magnetized bars of equal size and weight does not affect relocation, it seems that magnetism is responsible for the observed disorientation of these toads. Therefore, researchers have concluded that orientation toward breeding sites in these anurans is influenced by magnetic field information.
Magnetotaxis
Magnetotaxis is a process implemented by a diverse group of gram negative bacteria that involves orienting and coordinating movement in response to Earth's magnetic field . This process is mainly carried out by microaerophilic and anaerobic bacteria found in aquatic environments such as salt marshes, seawater, and freshwater lakes . By sensing the magnetic field, the bacteria are able to orient themselves towards environments with more favourable oxygen concentrations. This orientation towards more favourable oxygen concentrations allows the bacteria to reach these environments faster as opposed to if the bacteria were to move randomly to find these environments through Brownian Motion . After orienting, the bacteria use flagella to swim along the magnetic field, towards the more favourable environment . Magnetotaxis has no impact on the average speed of the bacteria. Once these bacteria die, they are able to orient themselves to the Earth's magnetic field but they are incapable of migrating along the field . These bacteria are now simply called magnetic bacteria .
Boom method
(a) Capturing of the magnetic beads.
During this suction process,
when the magnetic field are applied to the separation region of piper tip, from outside of pipette tip, by the magnet arranged on the outside of the pipette tip,
as liquid containing magnetic beads passes through a separation region of the pipette tip,
the magnetic particles are attracted to and arrested to the inner wall of tile separation region of pipette tip.
Magnetotactic bacteria
Magnetotactic bacterial cells have been used to determine south magnetic poles in meteorites and rocks containing fine-grained magnetic minerals and for the separation of cells after the introduction of magnetotactic bacterial cells into granulocytes and monocytes by phagocytosis. Magnetotactic bacterial magnetite crystals have been used in studies of magnetic domain analysis and in many commercial applications including: the immobilisation of enzymes; the formation of magnetic antibodies, and the quantification of immunoglobulin G; the detection and removal of "Escherichia coli" cells with a fluorescein isothiocyanate conjugated monoclonal antibody, immobilised on magnetotactic bacterial magnetite particles; and the introduction of genes into cells, a technology in which magnetosomes are coated with DNA and "shot" using a particle gun into cells that are difficult to transform using more standard methods.
Exchange bias
Exchange bias was initially used to stabilize the magnetization of soft ferromagnetic layers in readback heads based on the anisotropic magnetoresistance (AMR) effect. Without the stabilization, the magnetic domain state of the head could be unpredictable, leading to reliability problems. Currently exchange bias is used to pin the harder reference layer in spin valve readback heads and MRAM memory circuits that utilize the giant magnetoresistance or magnetic tunneling effect. Similarly the most advanced disk media are antiferromagnetically coupled, making use of interfacial exchange to effectively increase the stability of small magnetic particles whose behavior would otherwise be superparamagnetic.
Stingless bee
The bees were, and still are, treated as pets. Families would have one or many log-hives hanging in and around their houses. Although they are stingless, the bees do bite and can leave welts similar to a mosquito bite. The traditional way to gather bees, still favored among the locals, is find a wild hive, then the branch is cut around the hive to create a portable log, enclosing the colony. This log is then capped on both ends with another piece of wood or pottery and sealed with mud. This clever method keeps the melipine bees from mixing their brood, pollen, and honey in the same comb as do the European bees. The brood is kept in the middle of the hive, and the honey is stored in vertical "pots" on the outer edges of the hive. A temporary, replaceable cap at the end of the log allows for easy access to the honey while doing minimal damage to the hive. However, inexperienced handlers can still do irreversible damage to a hive, causing the hive to swarm and abscond from the log. With proper maintenance, though, hives have been recorded as lasting over 80 years, being passed down through generations. In the archaeological record of Mesoamerica, stone discs have been found that are generally considered to be the caps of long-disintegrated logs that once housed the beehives.
Magnetobiology
The magnetite model arose with the discovery of chains of single domain magnetite in certain bacteria in the 1970s. Histological evidence in a large number of species belonging to all major phyla. Honey bees have magnetic material in the front part of the abdomen while in vertebrates mostly in the ethmoid region of the head. Experiments prove that the input from magnetite-based receptors in birds and fish is sent over the ophthalmic nerve branch of the trigeminal nerve to the central nervous system.
Magnonics
Experimentally, there are many techniques that exist to study magnetic phenomena, each with its own limitations and advantages. The experimental techniques can be distinguished by being time-domain (optical and field pumped TR-MOKE), field-domain (ferromagnetic resonance (FMR)) and frequency-domain techniques (Brillouin light scattering (BLS), vector network analyser - ferromagnetic resonance (VNA-FMR)). Time-domain techniques allow the temporal evolution of the magnetisation to be traced indirectly by recording the polarisation response of the sample. The magnetisation can be inferred by the so-called 'Kerr' rotation. Field-domain techniques such as FMR tickle the magnetisation with a CW microwave field. By measuring the absorption of the microwave radiation through the sample, as an external magnetic field is swept provides information about magnetic resonances in the sample. Importantly, the frequency at which the magnetisation precesses depends on the strength of the applied magnetic field. As the external field strength is increased, so does the precession frequency. Frequency-domain techniques such as VNA-FMR, examine the magnetic response due to excitation by an RF current, the frequency of the current is swept through the GHz range and the amplitude of either the transmitted or reflected current can be measured.
Steven M. Reppert
In 2008, Reppert discovered the necessity of "Cry" for light-dependent magnetoreception responses in "Drosophila". He also showed that magnetoreception requires UVA/blue light, the spectrum corresponding with the action spectrum of "Drosophila" CRY.
These data were the first to genetically implicate CRY as a component of the input pathway or the chemical-based pathway of magnetoreception. Applying these findings to his work with the monarch, Reppert has shown that both monarch CRY1 and CRY2 proteins, when transgenically expressed in CRY-deficient flies, successfully restore magnetoreception function. These results propose the presence of a CRY-mediated magnetosensitivity system in monarchs that may act in concordance with the sun compass to aid navigation. In 2011, Reppert also discovered that human CRY2 can substitute as a functional magnetoreceptor in CRY-deficient flies, a discovery that warrants additional research into magnetosensitivity in humans.
Lesser bamboo bat
The bats are insectivorous, with flies, beetles, and hymenopterans forming the bulk of their diet. They catch insects on the wing, using echolocation calls that start at 125 kHz and drop to 50 kHz.
Ant nest beetle
Very little is known about the immature stages of ant nest beetles. Most appear to live in ant nests in their early stages of life. Although many are facultative or obligate myrmecophiles, most do not appear like ants (i.e. myrmecomorphic) and unlike in the case of myrmecophilous larval Lycaenidae, there appears to be no benefit gained by the ants in this association. Many species follow the trails of worker ants of specific species. Glandular secretions on their antennae and body allow them to interact with ant workers. It is believed that the beetles use an acoustic mechanism to successfully imitate the sounds of an ant queen thus permitting them access to the nest without alarming the ants.
The defensive bombardier behaviour is never used against ants. Males of some species are attracted to lights during some parts of the season and are thought to disperse from one ant nest to another. Males are thought to be short-lived. These beetles feed on ant eggs, larvae and adults by piercing their mandibles into the abdomen or other soft part and sucking the contents. Apart from chemical mimicry and communication with their hosts, they also make use of vibrations. Several stridulatory structures are found in these beetles including alary-elytral, abdomen-femur and thorax-femur combinations of surfaces.
Magnetoreception
Maghemite has been observed in platelets concentrated along the dendrites of the upper beak, consistently in the nanoscale. When in the nanoscale, iron oxides will remain permanently magnetized at lengths greater than 50 nm and will become magnetized at lengths smaller than 50 nm. Since these platelets have been observed in collections of 5-10, they are thought to form dipoles local to the dendrite they are present in. These local magnetic changes then cause a mechanical response along the membrane of the nerve cell, leading to a change in ion concentrations. This ion concentration, with respect to the other dendrite clusters is believed to form the magnetic sense.
Magnetoreception
The majority of study on magnetoreception in reptiles involves turtles. Some of the earliest support for magnetoreception in turtles was found in "Terrapene carolina", a species of box turtle. After successfully teaching a group of these box turtles to swim to either the east or west end of an experimental tank, the introduction of a strong magnet into the tank was enough to disrupt the learned routes. As such, the learning of oriented paths seems to rely on some internal magnetic compass possessed by box turtles. Subsequent discovery of magnetite in the dura mater of Sea Turtle hatchlings supported this conclusion, as magnetite provides a means by which magnetic fields may be perceived.
Magnetotactic bacteria
Two different magneto-aerotactic mechanisms—known as polar and axial—are found in different MTB strains. Some strains that swim persistently in one direction along the magnetic field (either north-seeking [NS] or south-seeking [SS])—mainly the magnetotactic cocci—are polar magneto-aerotactic. These magnetotactic bacteria will travel along the lines of the earth's magnetic field according to their orientation, but will swerve as a group and reverse direction if exposed to a local, more powerful and oppositely-oriented magnetic field. In this way, they continue to travel in the same magnetic direction, but relative instead to the local field. Those MTB that swim in either direction along magnetic field lines with frequent, spontaneous reversals of swimming direction without turning around—for example, freshwater spirilla—are axial magneto-aerotactic and the distinction between NS and SS does not apply to these bacteria. The magnetic field provides both an axis and a direction of motility for polar magneto-aerotactic bacteria, whereas it only provides an axis of motility for axial types of bacteria. In both cases, magnetotaxis increases the efficiency of aerotaxis in vertical concentration gradients by reducing a three-dimensional search to a single dimension.
Statistical learning in language acquisition
A related finding regarding statistical cues to phonological acquisition is a phenomenon known as the perceptual magnet effect. In this effect, a prototypical phoneme of a person’s native language acts as a “magnet” for similar phonemes, which are perceived as belonging to the same category as the prototypical phoneme. In the original test of this effect, adult participants were asked to indicate if a given exemplar of a particular phoneme differed from a referent phoneme. If the referent phoneme is a non-prototypical phoneme for that language, both adults and 6-month-old infants show less generalization to other sounds than they do for prototypical phonemes, even if the subjective distance between the sounds is the same. That is, adults and infants are both more likely to notice that a particular phoneme differs from the referent phoneme if that referent phoneme is a non-prototypical exemplar than if it is a prototypical exemplar. The prototypes themselves are apparently discovered through a distributional learning process, in which infants are sensitive to the frequencies with which certain sounds occur and treat those that occur most often as the prototypical phonemes of their language.
Varroa destructor
Mites reproduce on a 10-day cycle. The female mite enters a honey bee brood cell. As soon as the cell is capped, the "Varroa" mite lays eggs on the larva. The young mites, typically several females and one male, hatch in about the same time as the young bee develops and leave the cell with the host. When the young bee emerges from the cell after pupation, the "Varroa" mites also leave and spread to other bees and larvae. The mite preferentially infests drone cells, allowing the mite to reproduce one more time with the extra three days it takes a drone to emerge vs a worker bee. This can cause genetic defects such as useless wings or viruses and fungi in the bee.
Color vision
Many invertebrates have color vision. Honeybees and bumblebees have trichromatic color vision which is insensitive to red but sensitive to ultraviolet. "Osmia rufa", for example, possess a trichromatic color system, which they use in foraging for pollen from flowers. In view of the importance of color vision to bees one might expect these receptor sensitivities to reflect their specific visual ecology; for example the types of flowers that they visit. However, the main groups of hymenopteran insects excluding ants (i.e., bees, wasps and sawflies) mostly have three types of photoreceptor, with spectral sensitivities similar to the honeybee's." Papilio" butterflies possess six types of photoreceptors and may have pentachromatic vision. The most complex color vision system in the animal kingdom has been found in stomatopods (such as the mantis shrimp) with up to 12 spectral receptor types thought to work as multiple dichromatic units.
Magnetic trap (atoms)
Bose–Einstein condensation (BEC) requires conditions of very low density and very low temperature in a gas of atoms. Laser cooling in a magneto-optical trap (MOT) is typically used to cool atoms down to the microkelvin range. However, laser cooling is limited by the momentum recoils an atom receives from single photons. Achieving BEC requires cooling the atoms beyond the limits of laser cooling, which means the lasers used in the MOT must be turned off and a new method of trapping devised. Magnetic traps have been used to hold very cold atoms, while evaporative cooling has reduced the temperature of the atoms enough to reach BEC.
Magnetosome
Magnetosome are membranous structures present in magnetotactic bacteria (MTB). They contain iron-rich magnetic particles that are enclosed within a lipid bilayer membrane. Each magnetosome can often contain 15 to 20 magnetite crystals that form a chain which acts like a compass needle to orient magnetotactic bacteria in geomagnetic fields, thereby simplifying their search for their preferred microaerophilic environments. Recent research has shown that magnetosomes are invaginations of the inner membrane and not freestanding vesicles. Magnetite-bearing magnetosomes have also been found in eukaryotic magnetotactic algae, with each cell containing several thousand crystals.
Magnetoreception
There is also evidence for magnetoreception in large mammals. Resting and grazing cattle as well as roe deer ("Capreolus capreolus") and red deer ("Cervus elaphus") tend to align their body axes in the geomagnetic north-south direction. Because wind, sunshine, and slope could be excluded as common ubiquitous factors in this study, alignment toward the vector of the magnetic field provided the most likely explanation for the observed behaviour. However, because of the descriptive nature of this study, alternative explanations (e.g., the sun compass) could not be excluded. In a follow-up study, researchers analyzed body orientations of ruminants in localities where the geomagnetic field is disturbed by high-voltage power lines to determine how local variation in magnetic fields may affect orientation behaviour. This was done by using satellite and aerial images of herds of cattle and field observations of grazing roe deer. Body orientation of both species was random on pastures under or near power lines. Moreover, cattle exposed to various magnetic fields directly beneath or in the vicinity of power lines trending in various magnetic directions exhibited distinct patterns of alignment. The disturbing effect of the power lines on body alignment diminished with the distance from the conductors. In 2011 a group of Czech researchers, however, reported their failed attempt to replicate the finding using different Google Earth images.
Bat
Microbats make use of magnetoreception, in that they have a high sensitivity to the Earth's magnetic field, as birds do. Microbats use a polarity-based compass, meaning that they differentiate north from south, unlike birds, which use the strength of the magnetic field to differentiate latitudes, which may be used in long-distance travel. The mechanism is unknown but may involve magnetite particles.
Magnetoreception
In a choice test birds were trained to jump onto a platform on one end of a tunnel if there was no magnetic field present and to jump onto a platform on the other end of the tunnel if a magnetic field was present. In this test, birds were rewarded with a food prize and punished with a time penalty. Homing pigeons were able to make the correct choice 55%-65% of the time which is higher than what would be expected if the pigeons were simply guessing.
Bombus terrestris
Bumblebees and honey bees are extremely influenced by an innate preference for blue and yellow color. When they have no training, they will often just visit flowers that naturally attract them. However, it is generally thought that bees will learn to visit more nectar rewarding flowers after experience associates the reward with the color of the petals. This has been demonstrated in "B. terrestris," where bees trained on artificially colored flowers will pick a similar color to the one they were trained with when tested with an array of flower choices. If individuals were tested with flower colors significantly different than from what they were trained with, they just visited flowers most closely aligned with their innate color preferences. In addition to identifying specific colors for foraging purposes, it has also been shown that young worker bees have to learn complex motor skills in order to efficiently collect nectar and pollen from flowers. These skills might take several days to develop, as memory does not always hold perfectly on a day-to-day basis, sometimes deteriorating overnight. Even within a species, different populations have varying levels of innate blue preference and exhibit intraspecific variation in learning rate during association tasks. This is true of two subspecies of "B. terrestris", "B. terrestris dalmatinus" and "B. terrestris audax."
Mason bee
Solitary bees produce neither honey nor beeswax. They are immune from acarine and "Varroa" mites, but have their own unique parasites, pests, and diseases. The nesting habits of many Osmia lend themselves to easy cultivation, and a number of "Osmia" are commercially propagated in different parts of the world to improve pollination in fruit and nut production. Commercial pollinators include "O. lignaria, O. bicornis, O. cornuta, O. cornifrons, O. ribifloris", and "O. californica". They are used both as an alternative to and as an augmentation for European honey bees. Mason bees used for orchard and other agricultural applications are all readily attracted to nesting holes – reeds, paper tubes, nesting trays, or drilled blocks of wood; in their dormant season they can be transported as intact nests (tubes, blocks, etc.), or as loose cocoons. As is characteristic of solitary bees, "Osmia" are very docile and rarely sting when handled (only under distress such as when wet or squeezed), their sting is small and not painful, and their stinger is unbarbed.
Quantum biology
Experiments in the lab support the basic theory that radical-pair electrons can be significantly influenced by very weak magnetic fields, i.e. merely the direction of weak magnetic fields can affect radical-pair's reactivity and therefore can "catalyze" the formation of chemical products. Whether this mechanism applies to magnetoreception and/or quantum biology, that is, whether earth's magnetic field "catalyzes" the formation of "bio"chemical products by the aid of radical-pairs, is undetermined for two reasons. The first is that radical-pairs may need not be entangled, the key "quantum" feature of the radical-pair mechanism, to play a part in these processes. There are entangled and non-entangled radical-pairs. However, researchers found evidence for the radical-pair mechanism of magnetoreception when European robins, cockroaches, and garden warblers, could no longer navigate when exposed to a radio frequency that obstructs magnetic fields and radical-pair chemistry. To empirically suggest the involvement of entanglement, an experiment would need to be devised that could disturb entangled radical-pairs without disturbing other radical-pairs, or vice versa, which would first need to be demonstrated in a laboratory setting before being applied to in vivo radical-pairs.
Ochlerotatus triseriatus
Various mosquito traps can be used for the surveillance and control of "O. triseriatus" and other container-breeding "Aedes" species. Oviposition cups can be used to collect mosquito eggs. These cups are black plastic cups that are lined with seed germination paper or construction paper. Female mosquitoes will lay their eggs on the water line inside these cups, and the eggs will adhere to the paper. The paper can then be removed and taken to a laboratory for hatching, testing, or sampling. BG-Sentinel traps are traps that can be baited with CO and additional lures that target olfactory cues. Mosquitoes will be attracted to these lures, since they imitate the odors of the hosts they need for blood-feeding.  Furthermore, CDC light traps use a battery-operated light source, CO, and a fan that will attract and capture "Aedes" species effectively.
Magnetoreception
Studies of magnetoreception in vertebrate fish have been conducted mainly with salmon. For instance, the presence of an internal magnetic compass has been discovered in Sockeye Salmon ("Oncorhynchus nerka"). Researchers made this discovery by first placing the young of this species in a symmetrical, circular tank and allowing them to pass through exits in the tank freely. A mean vector was then calculated to represent the directional preferences of these salmon in the natural magnetic field. Notably, when the magnetic field was experimentally rotated, the directional preferences of the young Sockeye Salmon changed accordingly. As such, researchers concluded that the orientation of swimming behaviour in Sockeye Salmon is influenced by magnetic field information.
Varroa
Bee-breeding efforts to develop resistance against "Varroa" are ongoing. The USDA has developed a line of bees which uses "Varroa"-sensitive hygiene to remove reproductive mites. This line is now being distributed to beekeepers to be used as part of their integrated pest management programs.
Mite biting bees
Mite biting bees is a natural defensive behavior of honeybees to fight off the ectoparasitic mites Varroa destructor . This behavior has been studied for several decades for honeybee breeding and improve honeybee stocks on mite resistance. A group effort at Purdue University started an artificial selection of mite biting behavior of European Honeybees with Heartland Honey Bee Breeding Coop (HHBBC)
Bee
Bees are flying insects closely related to wasps and ants, known for their role in pollination and, in the case of the best-known bee species, the western honey bee, for producing honey and beeswax. Bees are a monophyletic lineage within the superfamily Apoidea and are presently considered a clade, called Anthophila. There are nearly 20,000 known species of bees in seven recognized biological families. They are found on every continent except Antarctica, in every habitat on the planet that contains insect-pollinated flowering plants.
Biomineralization
The most ancient example of biomineralization, dating back 2 billion years, is the deposition of magnetite, which is observed in some bacteria, as well as the teeth of chitons and the brains of vertebrates; it is possible that this pathway, which performed a magnetosensory role in the common ancestor of all bilaterians, was duplicated and modified in the Cambrian to form the basis for calcium-based biomineralization pathways. Iron is stored in close proximity to magnetite-coated chiton teeth, so that the teeth can be renewed as they wear. Not only is there a marked similarity between the magnetite deposition process and enamel deposition in vertebrates but some vertebrates even have comparable iron storage facilities near their teeth.
Magnetoreception
The nematode "Caenorhabditis elegans" was proposed to orient to the magnetic field of the Earth using the first described set of magnetosensory neurons. Worms appear to use the magnetic field to orient during vertical soil migrations that change in sign depending on their satiation state (with hungry worms burrowing down, and satiated worms burrowing up). However, recent evidence challenges these findings.
Sea turtle migration
In regards to the magnetic field hypothesis, there are three main concepts that should be considered. The concepts include electromagnetic induction, magnetic field chemical reactions, and magnetite. In regards to electromagnetic induction, it is assumed that the sea turtles have electroreceptors. Although evidence has been found in other species such as rays and sharks, no evidence has shown that there are electroreceptors in sea turtles making this hypothesis invalid. A second concept from the experimentation by Irwin involves chemical reactions which is commonly found in a variety of species of newts and birds. The strength of the magnetic field affects the chemical reactions within the bodies of the newts and birds. The final concept includes the magnetic crystals that form during the magnetic pulses from the earth’s magnetic fields. These magnetic crystals formed by magnetite give the turtles directional information and guides in migration. The magnetite affects the cells of the nervous system of the sea turtle by producing a signal that references the forces of the magnetic field and the direction and magnitude that is applied. If this magnetite is used in the migration, when the earth’s magnetic poles reverse at the dipole moment, the signal that the sea turtle nervous system receives will change the migration direction. Regardless of the hypothesis, hatchling turtles have the ability to determine the direction and inclination angle of which they are swimming with aide from magnetic fields.
Magnetotactic bacteria
The biomineralisation of magnetite () requires regulating mechanisms to control the concentration of iron, the crystal nucleation, the redox potential and the acidity (pH). This is achieved by means of compartmentalisation in structures known as magnetosomes that allow the biochemical control of the above-mentioned processes. After the genome of several MTB species had been sequenced, a comparative analysis of the proteins involved in the formation of the BMP became possible. Sequence homology with proteins belonging to the ubiquitous cation diffusion facilitator (CDF) family and the "Htr-like" serine proteases has been found. While the first group is exclusively dedicated to the transport of heavy metals, the second group consists of heat shock proteins (HSPs) involved in the degradation of badly folded proteins. Other than the serine protease domain, some proteins found in the magnetosomial membrane (MM) also contain PDZ domains, while several other MM proteins contain tetratricopeptide repeat (TPR) domains.
Electroreception
Until recently, electroreception was known only in vertebrates. Recent research has shown that bees can detect the presence and pattern of a static charge on flowers. In vertebrates, electroreception is an ancestral trait, that is to say that it was present in the last common ancestor of all vertebrates.. This form of ancestral electroreception is called ampullary electroreception, with the receptive organs themselves called Ampullae of Lorenzini. Not all vertebrates that possess electroreception have Ampullae of Lorenzini. Ampullae of Lorenzini exist in cartilaginous fishes (sharks, rays, chimaeras), lungfishes, bichirs, coelacanths, sturgeons, paddlefish, aquatic salamanders, and caecilians. Other vertebrates that have electroreception such as catfish, gymnotiformes, Mormyridiformes, monotremes, and at least one species of cetacean all have different secondarily derived forms of electroreception. Ampullary electroreception is "passive", and is used predominantly in predation. Two groups of teleost fishes are weakly electric and engage in "active" electroreception; the Neotropical knifefishes (Gymnotiformes) and the African elephantfishes (Notopteroidei). A rare terrestrial exception is the Western long-beaked echidna which has about 2,000 electroreceptors on its bill, compared to 40,000 for its semi-aquatic monotreme relative, the duck-billed platypus.
Magnetoreception
Magnetoreception is present in bacteria, arthropods, molluscs and members of all major taxonomic groups of vertebrates. Humans are not thought to have a magnetic sense, but there is a protein (a cryptochrome) in the eye which could serve this function.
Magnetite
Some researchers also suggest that humans possess a magnetic sense, proposing that this could allow certain people to use magnetoreception for navigation. The role of magnetite in the brain is still not well understood, and there has been a general lag in applying more modern, interdisciplinary techniques to the study of biomagnetism.
Insect
Many insects possess very sensitive and specialized organs of perception. Some insects such as bees can perceive ultraviolet wavelengths, or detect polarized light, while the antennae of male moths can detect the pheromones of female moths over distances of many kilometers. The yellow paper wasp ("Polistes versicolor") is known for its wagging movements as a form of communication within the colony; it can waggle with a frequency of 10.6±2.1 Hz (n=190). These wagging movements can signal the arrival of new material into the nest and aggression between workers can be used to stimulate others to increase foraging expeditions. There is a pronounced tendency for there to be a trade-off between visual acuity and chemical or tactile acuity, such that most insects with well-developed eyes have reduced or simple antennae, and vice versa. There are a variety of different mechanisms by which insects perceive sound; while the patterns are not universal, insects can generally hear sound if they can produce it. Different insect species can have varying hearing, though most insects can hear only a narrow range of frequencies related to the frequency of the sounds they can produce. Mosquitoes have been found to hear up to 2 kHz, and some grasshoppers can hear up to 50 kHz. Certain predatory and parasitic insects can detect the characteristic sounds made by their prey or hosts, respectively. For instance, some nocturnal moths can perceive the ultrasonic emissions of bats, which helps them avoid predation. Insects that feed on blood have special sensory structures that can detect infrared emissions, and use them to home in on their hosts.
Magnetoreception
Aside from the sensory receptor for magnetic reception in homing pigeons there has been work on neural regions that are possibly involved in the processing of magnetic information within the brain. Areas of the brain that have shown increases in activity in response to magnetic fields with a strength of 50 or 150 microtesla are the posterior vestibular nuclei, dorsal thalamus, hippocampus, and visual hyperpallium.
Megachilidae
Megachilidae is a cosmopolitan family of mostly solitary bees whose pollen-carrying structure (called a "scopa") is restricted to the ventral surface of the abdomen (rather than mostly or exclusively on the hind legs as in other bee families). Megachilid genera are most commonly known as mason bees and leafcutter bees, reflecting the materials from which they build their nest cells (soil or leaves, respectively); a few collect plant or animal hairs and fibers, and are called carder bees, while others use plant resins in nest construction and are correspondingly called resin bees. All species feed on nectar and pollen, but a few are kleptoparasites (informally called "cuckoo bees"), feeding on pollen collected by other megachilid bees. Parasitic species do not possess scopae. The motion of Megachilidae in the reproductive structures of flowers is energetic and swimming-like; this agitation releases large amounts of pollen.
Magnetic separation
Magnetic Separation is which separating components of mixtures by using magnets to attract magnetically susceptible materials. This separation technique can be useful in mining iron as it is attracted to a magnet. 
In mines where wolframite was mixed with cassiterite, such as South Crofty and East Pool mine in Cornwall or with bismuth such as at the Shepherd and Murphy mine in Moina, Tasmania, magnetic separation is used to separate the ores. At these mines, a device called a Wetherill's Magnetic Separator (invented by John Price Wetherill, 1844–1906) was used. In this machine, the raw ore, after calcination was fed onto a conveyor belt which passed underneath two pairs of electromagnets under which further belts ran at right angles to the feed belt. The first pair of balls was weakly magnetized and served to draw off any iron ore present. The second pair were strongly magnetized and attracted the wolframite, which is weakly magnetic. These machines were capable of treating 10 tons of ore a day.
Magnetite
Pure magnetite particles are biomineralized in magnetosomes, which are produced by several species of magnetotactic bacteria. Magnetosomes consist of long chains of oriented magnetite particle that are used by bacteria for navigation. After the death of these bacteria, the magnetite particles in magnetosomes may be preserved in sediments as magnetofossils. Some types of anaerobic bacteria that are not magnetotactic can also create magnetite in oxygen free sediments by reducing amorphic ferric oxide to magnetite.
Precision beekeeping
Audio signals and audio processing techniques can be applied to estimate bee behaviour. Many devices and methods have been developed for sound analysis but they are not widely applied in industrial beekeeping. So far, the solutions seem to work only in the hands of researchers. The reason for this may be the large stochastic component in the buzz of a colony and the complexity of sound interpretation. As well means of a simple transducer secured to the outside wall of a hive, a set of statistically independent instantaneous vibration signals of honey bees can be identified and monitored in time using a fully automated and non-invasive method.
Bee learning and communication
Menzel found that bees register color during both approach and feeding, and that they had to see the color for about a total of about 5 seconds, with best performance usually coming with about three seconds exposure during the approach and two seconds after landing and beginning to feed.
Barber's pole
The strength and direction of magnetic fields and electric currents can be measured using a "magnetoresistive barber-pole sensor" (also called a "hermetic proximity sensor"), and its performance can be depicted using a mathematical formula. Such a sensor interleaves a series of permanent magnet strips with a series of magnetoresistive strips. The "conductive barberpole strips are canted across the sensor and connect one magnetoresistive strip, over a permanent magnet strip, to another magnetoresistive strip." This is said to provide a "uniform magnetic field throughout the sensor" thereby enhancing its resistance to external magnetic fields. The technology is used in wireless sensor networks which "have gathered a lot of attention as an important research domain" and were "deployed in many applications, "e.g.", navigation, military, ambient intelligence, medical, and industrial tasks. Context-based processing and services, in particular location-context, are of key interest ..." (See Music (acoustic illusion), infra.)
Magnetotactic bacteria
Richard Blakemore, then a Microbiology graduate student at the University of Massachusetts at Amherst, working in the Woods Hole Oceanographic Institution in whose collections the pertinent publications of the Institute of Microbiology of the University of Pavia were extant, observed microorganisms following the direction of Earth's magnetic field. Blakemore did not mention Bellini's research in his own report, which he published in "Science", but was able to observe magnetosome chains using an electron microscope. Bellini's terms for this behavior, namely , or , and (Bellini's first publication, last page), went forgotten, and Blakemore's "magnetotaxis" was adopted by the scientific community.
Magnetic immunoassay
The presence of magnetic beads is then detected by a magnetic reader (magnetometer) which measures the magnetic field change induced by the beads. The signal measured by the magnetometer is proportional to the analyte (virus, toxin, bacteria, cardiac marker,etc.) concentration in the initial sample.
Animal navigation
Some animals, notably insects such as the honey bee, are sensitive to the polarisation of light. Honey bees can use polarized light on overcast days to estimate the position of the sun in the sky, relative to the compass direction they intend to travel. Karl von Frisch's work established that bees can accurately identify the direction and range from the hive to a food source (typically a patch of nectar-bearing flowers). A worker bee returns to the hive and signals to other workers the range and direction relative to the sun of the food source by means of a waggle dance. The observing bees are then able to locate the food by flying the implied distance in the given direction, though other biologists have questioned whether they necessarily do so, or are simply stimulated to go and search for food. However, bees are certainly able to remember the location of food, and to navigate back to it accurately, whether the weather is sunny (in which case navigation may be by the sun or remembered visual landmarks) or largely overcast (when polarised light may be used).
Bee
The earliest animal-pollinated flowers were shallow, cup-shaped blooms pollinated by insects such as beetles, so the syndrome of insect pollination was well established before the first appearance of bees. The novelty is that bees are specialized as pollination agents, with behavioral and physical modifications that specifically enhance pollination, and are the most efficient pollinating insects. In a process of coevolution, flowers developed floral rewards such as nectar and longer tubes, and bees developed longer tongues to extract the nectar. Bees also developed structures known as scopal hairs and pollen baskets to collect and carry pollen. The location and type differ among and between groups of bees. Most bees have scopal hairs located on their hind legs or on the underside of their abdomens, some bees in the family Apidae possess pollen baskets on their hind legs while very few species lack these entirely and instead collect pollen in their crops. This drove the adaptive radiation of the angiosperms, and, in turn, the bees themselves. Bees have not only coevolved with flowers but it is believed that some bees have coevolved with mites. Some bees provide tufts of hairs called acarinaria that appear to provide lodgings for mites; in return, it is believed that the mites eat fungi that attack pollen, so the relationship in this case may be mutualistc.
Immunoprecipitation
Using the traditional batch method of immunoprecipitation as listed below, where all components are added to a tube during the IP reaction, the physical handling characteristics of agarose beads necessitate a minimum quantity of beads for each IP experiment (typically in the range of 25 to 50μl beads per IP). This is because sepharose beads must be concentrated at the bottom of the tube by centrifugation and the supernatant removed after each incubation, wash, etc. This imposes absolute physical limitations on the process, as pellets of agarose beads less than 25 to 50μl are difficult if not impossible to visually identify at the bottom of the tube. With magnetic beads, there is no minimum quantity of beads required due to magnetic handling, and therefore, depending on the target antigen and IP antibody, it is possible to use considerably less magnetic beads.
Magnetotactic bacteria
Regardless of their morphology, all MTB studied so far are motile by means of flagella and are gram-negative bacteria of various phyla. Despite the majority of known species' being proteobacteria, e.g. "Magnetospirillum magneticum" an alphaproteobacterium, members of various phyla possess the magnetosome gene cluster, such as "Candidatus Magnetobacterium bavaricum" a Nitrospira. The arrangement of flagella differs and can be polar, bipolar, or in tufts. The first phylogenetic analysis on magnetotactic bacteria using 16S rRNA gene sequence comparisons was performed by P. Eden et al. in 1991.
Magnetic detector
The device works by hysteresis of the magnetization in the iron wires. The permanent magnets are arranged to create two opposite magnetic fields each directed toward (or away) from the center of the coils in opposite directions along the wire. This functions to magnetize the iron band along its axis, first in one direction as it approaches the center of the coils, then reverse its magnetism to the opposite direction as it leaves from the other side of the coil. Due to the hysteresis (coercivity) of the iron, a certain threshold magnetic field (the coercive field, "H") is required to reverse the magnetization. So the magnetization in the moving wires does not reverse in the center of the device where the field reverses, but some way toward the departing side of the wires, when the field of the second magnet reaches "H". Although the wire itself is moving through the coil, in the absence of a radio signal the location where the magnetization "flips" is stationary with respect to the pickup coil, so there is no flux change and no voltage is induced in the pickup coil.
Hive management
Bee venom (apitoxin) is obtained by stimulating the bee with an electric current that incite them to sting, releasing a drop of poison onto a glass slide. The crystallized venom can be collected and processed. In order to get 1 gram of dry venom, it is necessary to collect the apitoxin of 10,000 to 15,000 bees.
Bee brood as such is generally not a commercial commodity. However, bee brood is edible, and is used as a food in Asia and Africa.
Photoreceptor cell
The pineal and parapineal glands are photoreceptive in non-mammalian vertebrates, but not in mammals. Birds have photoactive cerebrospinal fluid (CSF)-contacting neurons within the paraventricular organ that respond to light in the absence of input from the eyes or neurotransmitters. Invertebrate photoreceptors in organisms such as insects and molluscs are different in both their morphological organization and their underlying biochemical pathways. Described here are human photoreceptors.
Immunoprecipitation
The price of using either type of support is a key determining factor in using agarose or magnetic beads for immunoprecipitation applications. A typical first-glance calculation on the cost of magnetic beads compared to sepharose beads may make the sepharose beads appear less expensive. But magnetic beads may be competitively priced compared to agarose for analytical-scale immunoprecipitations depending on the IP method used and the volume of beads required per IP reaction.
Magnetoreception
Despite more than 50 years of research, a sensory receptor in animals has yet to be identified for magnetoreception. While research is ongoing, it is possible that the entire receptor system could fit in a one-milimeter cube and have a magnetic content of less than one ppm. As such, even discerning the parts of the brain where the information is processed presents a challenge.
Electroreception
Electroreceptive animals use this sense to locate objects around them. This is important in ecological niches where the animal cannot depend on vision: for example in caves, in murky water and at night. Many fish use electric fields to detect buried prey. Some shark embryos and pups "freeze" when they detect the characteristic electric signal of their predators. It has been proposed that sharks can use their acute electric sense to detect the earth's magnetic field by detecting the weak electric currents induced by their swimming or by the flow of ocean currents. The walking behaviour of cockroaches can be affected by the presence of a static electric field: they like to avoid the electric field. Cabbage loopers are also known to avoid electric fields.
Gene therapy for epilepsy
Magnetofection is done through the use of super paramagnetic iron oxide nanoparticles coated with polyethylenimine. Iron oxide nanoparticles are ideal for biomedical applications in the body due to their biodegradable, cationic, non-toxic, and FDA-approved nature. Under gene transfer conditions, the receptors of interest are coated with the nanoparticles. The receptors will then home in and travel to the target of interest. Once the particle docks, the DNA is delivered to the cell via pinocytosis or endocytosis. Upon delivery, the temperature is increased ever so slightly, lysing the iron oxide nanoparticle and releasing the DNA. Overall, the technique is useful for combatting slow vector accumulation and low vector concentration at target areas. The technique is also customizable to the physical and biochemical properties of the receptors by modifying the characteristics of the iron oxide nanoparticles.
Immunoprecipitation
As mentioned above, only standard laboratory equipment is required for the use of agarose beads in immunoprecipitation applications, while high-power magnets are required for magnetic bead-based IP reactions. While the magnetic capture equipment may be cost-prohibitive, the rapid completion of immunoprecipitations using magnetic beads may be a financially beneficial approach when grants are due, because a 30-minute protocol with magnetic beads compared to overnight incubation at 4 °C with agarose beads may result in more data generated in a shorter length of time.
List of diseases of the honey bee
Common chemical controls include "hard" chemicals such as Amitraz (marketed as Apivar ), fluvalinate (marketed as Apistan), and coumaphos (marketed as CheckMite). "Soft" chemical controls include thymol (marketed as ApiLife-VAR and Apiguard), sucrose octanoate esters (marketed as Sucrocide), oxalic acid and formic acid (sold in liquid form or in gel strips as Mite Away Quick Strips and Formic Pro, but also used in other formulations). According to the U.S. Environmental Protection Agency, when used in beehives as directed, these treatments kill a large proportion of the mites while not substantially disrupting bee behavior or life span. Use of chemical controls is generally regulated and varies from country to country. With few exceptions, they are not intended for use during production of marketable honey.
Common mechanical controls generally rely on disruption of some aspect of the mites' lifecycle. These controls are generally intended not to eliminate all mites, but merely to maintain the infestation at a level which the colony can tolerate. Examples of mechanical controls include drone brood sacrifice (varroa mites are preferentially attracted to the drone brood), powdered sugar dusting (which encourages cleaning behavior and dislodges some mites), screened bottom boards (so any dislodged mites fall through the bottom and away from the colony), brood interruption and, perhaps, downsizing of the brood cell size. A device called the varroa mite control entrance (VMCE) is under development as of 2008. The VMCE works in conjunction with a screened bottom board, by dislodging varroa mites from bees as they enter and exit a hive.
Magnetic bearing
Jesse Beams from the University of Virginia filed some of the earliest active magnetic bearing patents during World War II. The patents dealt with ultracentrifuges intended for the enrichment of isotopes of elements needed for the Manhattan Project. However, magnetic bearings did not mature until advances in solid-state electronics and modern computer-based control technology with the work of Habermann and Schweitzer. In 1987, Estelle Croot further improved active magnetic bearing technology, but these designs were not manufactured due to expensive costs of production, which used a laser guidance system. Estelle Croot's research was the subject of three Australian patents  and was funded by Nachi Fujikoshi, Nippon Seiko KK and Hitachi, and her calculations were used in other technologies that used rare earth magnets but the active magnetic bearings were only developed to the prototype stage.
Boom method
Here, "ease of collection" is defined and compared by
"magnetic beads are collected by not less than X wt % (～90wt %) within T seconds(～ 3 seconds) in the presence of a magnetic field of Y gauss (～3000 gauss) when it is dispersed in an amount of at least Z mg (～20 mg) in W mL (～1 mL) of an aqueous solution of a sample containing a biological substance" and, capture ability are defined and compared by
"binding with at least A μg (～0.4μg) of the biological substance per B mg (～1 mg) thereof
when it is dispersed in an amount of at least Z mg (～20 mg) in W mL (～1 mL) of an aqueous solution of a sample containing a biological substance".
The principle of this method is based on the nucleic acid-binding properties of silica particles or diatoms in the presence of this chaotropic agent, which are according to the chaotropic effect.
Bee learning and communication
A seminal paper by Menzel (1975) described the morphology and spectral sensitivity of the honey bee eye that underlie their color vision. He examined color-coding in the honey bee retina by marking individual cells with a fluorescent dye and recording from these cells as single units. From this analysis he determined that there are three types of receptors in the honey bee eye: 1) UV receptors, 2) blue receptors, and 3) green receptors The three receptors contain three rhodopsin-like pigments which have maximal absorbance at wavelengths of 350 nm, 440 nm, and 540 nm. Menzel also found that most of the cells he studied had secondary sensitivities that corresponded to wavelength regions at which the other two receptor types were maximally active. He used spectral efficiency experiments to suggest that these secondary sensitivities result from electric coupling between the receptors.
Magnetic nanoparticles
Magnetic nanoparticles can be used for a variety of genetics applications. One application is the rapid isolation of mRNA. In one application, the magnetic bead is attached to a poly T tail. When mixed with mRNA, the poly A tail of the mRNA will attach to the bead's poly T tail and the isolation takes place simply by placing a magnet on the side of the tube and pouring out the liquid. Magnetic beads have also been used in plasmid assembly. Rapid genetic circuit construction has been achieved by the sequential addition of genes onto a growing genetic chain, using nanobeads as an anchor. This method has been shown to be much faster than previous methods, taking less than an hour to create functional multi-gene constructs in vitro.
Magnetic shark repellent
Several species of sharks have demonstrated the ability to sense magnetic fields (Kalmijn, 1978; Ryan, 1980; Klimley, 1993; 2002). The Ampullae of Lorenzini organ within sharks is used to detect weak electrical fields at short ranges. The detection range of this organ is effective only within inches, as sharks sense bioelectrical fields in the final stages of prey capture. The flux per unit area of certain permanent magnets, particularly Neodymium-Iron-Boride and Barium-Ferrite magnets, corresponds closely with the detection range of the Ampullae of Lorenzini. The fields generated by these permanent magnets (ferrite and rare-earth types) decrease at the inverse cube of the distance from the magnet to sharks and rays. Therefore, at distances of a few meters from the magnet, the field exerted is less than the Earth's magnetic field. Animals which lack that Ampullae of Lorenzini organ do not display aversive behavior in close proximity to the magnetic field, making this technology selective.
Schwarziana quadripunctata
A similar 2005 study by Lucano et al. observed the same nest of "Schwarziana quadripunctata" to determine the location of the bodily magnetoreceptors. After separating the head, thorax, abdomen and antennae of a dozen stingless bees, magnetic fields were applied to each body part. It was found that the head, thorax, and abdomen present a diamagnetic contribution (inducing a magnetic field opposite to the applied field), while the antennae displayed a paramagnetic one (inducing a magnetic field in the same direction as the applied field). The antennae of the stingless bee, therefore, exist as a complex sensory organ used for orientation and navigation through the combined use of thousands of hair-shaped sensilla.
Magnetospirillum
Probably the most peculiar characteristic of "Magnetospirillum" species is their capacity to orient themselves according to Earth's magnetic field, magnetotaxis. This is achieved through the presence in the bacterium's cytoplasm of special organelles called magnetosomes. "Magnetospirillum" species also resort to aerotaxis, to remain in favorable O concentration conditions. When the bacteria ingest iron, proteins inside their cells interact with it to produce tiny crystals of the mineral magnetite, the most magnetic mineral on Earth.
Magnetite
Several species of birds are known to incorporate magnetite crystals in the upper beak for magnetoreception, which (in conjunction with cryptochromes in the retina) gives them the ability to sense the direction, polarity, and magnitude of the ambient magnetic field.
Magnetotactic bacteria
From a thermodynamic point of view, in the presence of a neutral pH and a low redox potential, the inorganic synthesis of magnetite is favoured when compared to those of other iron oxides. It would thus appear microaerophilic or anaerobic conditions create a suitable potential for the formation of BMPs. Moreover, all iron absorbed by the bacteria is rapidly converted into magnetite, indicating the formation of crystals is not preceded by the accumulation of intermediate iron compounds; this also suggests the structures and the enzymes necessary for biomineralisation are already present within the bacteria. These conclusions are also supported by the fact that MTB cultured in aerobic conditions (and thus nonmagnetic) contain amounts of iron comparable to any other species of bacteria.
Bacterial cell structure
Magnetosomes are bacterial microcompartments found in magnetotactic bacteria that allow them to sense and align themselves along a magnetic field (magnetotaxis). The ecological role of magnetotaxis is unknown but is thought to be involved in the determination of optimal oxygen concentrations. Magnetosomes are composed of the mineral magnetite or greigite and are surrounded by a lipid bilayer membrane. The morphology of magnetosomes is species-specific.
Magnetoreception
These iron clusters have been observed in two types of compounds: magnetite (FeO) and maghemite (γ-FeO). Both are believed to play a part in the magnetic sense, particularly for the magnetic map sense. These concentrations are believed to be connected to the central nervous system to form a sensing system. Research has focused on magnetite concentrations, however, magnetite alone has been shown to not be in magnetosensitive neurons.
Bombus terrestris
In their 2014 study published in "Functional Ecology" researchers using Radio-Frequency Identification (RFID) tagging technology on the bees, found that a sublethal exposure to either a neonicotinoid (imidacloprid) and/or a pyrethroid (?-cyhalothrin) over a four-week period caused an impairment of the bumblebee's ability to forage. Research published in 2015 showed that bees prefer solutions containing neonicotinoids, even though the consumption of these pesticides caused them to eat less food overall. This work implies that treating flowering crops with such pesticides presents a sizeable hazard to foraging bees.
Bee learning and communication
Odor learning in bees is usually tested by the proboscis extension reflex. Significant to the argument are the experiments of William F. Towne, of the Kutztown University in Pennsylvania, in which hives are moved to "mirror image" terrain settings, and the bees are thereby fooled into dancing about the wrong location for a nectar source. Foragers were successfully recruited to the wrong location, but only when the sun was obscured by clouds, forcing them to rely on terrain-based navigation rather than "solar ephemeris"-based navigation. As the cloud cover broke up, more and more bees corrected their dances to indicate the actual location of nectar, and forager visits shifted to the correct location.
Bee
Vertebrate predators of bees include bee-eaters, shrikes and flycatchers, which make short sallies to catch insects in flight. Swifts and swallows fly almost continually, catching insects as they go. The honey buzzard attacks bees' nests and eats the larvae. The greater honeyguide interacts with humans by guiding them to the nests of wild bees. The humans break open the nests and take the honey and the bird feeds on the larvae and the wax. Among mammals, predators such as the badger dig up bumblebee nests and eat both the larvae and any stored food. North American bears were particularly fond of honey.
Magnetite
The chemical composition of magnetite is FeFeO. The main details of its structure were established in 1915. It was one of the first crystal structures to be obtained using X-ray diffraction. The structure is inverse spinel, with O ions forming a face centered cubic lattice and iron cations occupying interstitial sites. Half of the Fe cations occupy tetrahedral sites while the other half, along with Fe cations, occupy octahedral sites. The unit cell consists of 32 O ions and unit cell length is "a" = 0.839 nm.
Magnetic nanoparticles
Magnetic immunoassay (MIA) is a novel type of diagnostic immunoassay utilizing magnetic nanobeads as labels in lieu of conventional, enzymes, radioisotopes or fluorescent moieties. This assay involves the specific binding of an antibody to its antigen, where a magnetic label is conjugated to one element of the pair. The presence of magnetic nanobeads is then detected by a magnetic reader (magnetometer) which measures the magnetic field change induced by the beads. The signal measured by the magnetometer is proportional to the analyte (virus, toxin, bacteria, cardiac marker,etc.) quantity in the initial sample.
Magnetoreception
A number of amphibians and reptiles including salamanders, toads and turtles exhibit alignment behaviours with respect to the Earth's magnetic field.
Magnetosome
Magnetotactic bacteria usually mineralize either iron oxide magnetosomes, which contain crystals of magnetite (), or iron sulfide magnetosomes, which contain crystals of greigite (). Several other iron sulfide minerals have also been identified in iron sulfide magnetosomes—including mackinawite (tetragonal ) and a cubic —which are thought to be precursors of . One type of magnetotactic bacterium present at the oxic-anoxic transition zone (OATZ) of the southern basin of the Pettaquamscutt River Estuary, Narragansett, Rhode Island, United States is known to produce both iron oxide and iron sulfide magnetosomes.
Magnetoreception
Domestic hens have iron mineral deposits in the dendrites in the upper beak and are capable of magnetoreception. Because hens use directional information from the magnetic field of the Earth to orient in relatively small areas, this raises the possibility that beak-trimming (removal of part of the beak, to reduce injurious pecking, frequently performed on egg-laying hens) impairs the ability of hens to orient in extensive systems, or to move in and out of buildings in free-range systems.
Magnetic storage
A write head magnetises a region by generating a strong local magnetic field, and a read head detects the magnetisation of the regions. Early HDDs used an electromagnet both to magnetise the region and to then read its magnetic field by using electromagnetic induction. Later versions of inductive heads included Metal In Gap (MIG) heads and thin film heads. As data density increased, read heads using magnetoresistance (MR) came into use; the electrical resistance of the head changed according to the strength of the magnetism from the platter. Later development made use of spintronics; in read heads, the magnetoresistive effect was much greater than in earlier types, and was dubbed "giant" magnetoresistance (GMR). In today's heads, the read and write elements are separate, but in close proximity, on the head portion of an actuator arm. The read element is typically magneto-resistive while the write element is typically thin-film inductive.
Pain in invertebrates
Honeybees extend their proboscis when learning about novel odours. In one study on this response, bees learnt to discriminate between two odours, but then learned to suppress the proboscis extension response when one of the odours was paired with an electric shock. This indicates the sensation was aversive to the bee, however, the response was plastic rather than simply reflexive, indicating pain rather than nociception.
Magnetoreception
Subsequent research has examined magnetoreception in a more natural setting. Under typical circumstances, red-spotted newts ("Notophthalmus viridescens)" respond to drastic increases in water temperature (which tend to indicate environmental deterioration) by orienting themselves toward the shoreline and heading for land. However, when magnetic fields are experimentally altered, this behaviour is disrupted, and assumed orientations fail to direct the newts to the shoreline. Moreover, the change in orientation corresponds to the degree by which the magnetic field is shifted. In other words, inversion of the magnetic poles (a 180° shift) results in inversion of the typical orientation (a 180° shift). Further research has shown that magnetic information is not only used by red-spotted newts for orientation toward the shoreline, but also in orientation toward their home pools. Ultimately, it seems as though red-spotted newts rely on information regarding the Earth’s magnetic field for navigation within their environment, in particular when orienting toward the shoreline or toward home.
Bee learning and communication
Honey bees are sensitive to odors (including pheromones), tastes, and colors, including ultraviolet. They can demonstrate capabilities such as color discrimination through classical and operant conditioning and retain this information for several days at least; they communicate the location and nature of sources of food; they adjust their foraging to the times at which food is available; they may even form cognitive maps of their surroundings.
Chiton
The radular teeth of chitons are made of magnetite, and the iron crystals within these may be involved in magnetoception, the ability to sense the polarity or the inclination of the Earth's magnetic field. Experimental work has suggested that chitons can detect and respond to magnetism.
Macropis
They are solitary bees that dig their nests in the ground. Most species are oligolectic and feed on pollen and floral oils of "Lysimachia" spp. They make a single generation per year. The males emerge from the ground in spring, just before the females, and await the females in the vicinity of the flowers of the host plant. After mating, the females dig a nest in the ground, ending with one or two rooms in which is collected the pollen, which is placed on the egg. The larvae, feeding on the pollen, develop rapidly, and within 10 days turn into pupae, spending the winter in this stage. "Macropis" nests are often parasitized by bee cleptoparasites such as "Epeoloides".
Xylocopa micans
Southern carpenter bees are nectarivores. Males will forage from 12 PM until 4 PM at the latest during the summer months, although males with territories will forage for only one hour before returning to defend their territories. "X. micans" bees exhibit risk sensitive foraging, where bees demonstrate risk-aversion to completely empty flowers and favor flowers with nectar. "X. micans" is also polylectic, meaning that "X. micans" bees are general pollinators and can collect pollinators from a broad variety of plants. They also have special abilities for pollination, since they are capable of buzz pollination, a technique that allows the bees to dislodge tightly held pollen using resonant vibration. This ability expands the types of plants that "X. micans" is capable of foraging on.
European robin
The avian magnetic compass of the robin has been extensively researched and uses vision-based magnetoreception, in which the robin's ability to sense the magnetic field of the earth for navigation is affected by the light entering the bird's eye. The physical mechanism of the robin's magnetic sense is not fully understood, but may involve quantum entanglement of electron spins.
Euglossa imperialis
Contrary to most other bee species which have a short proboscis to consume nectar with a lapping motion of their hair-covered tongues, the long-tongued "Euglossini" bees utilize a purely suction feeding method to ingest nectar from deep flowers, such as flowering orchid plants. However, because of the dilemma the euglossine bees face—in which energy content rises linearly with nectar sugar concentration, whereas viscosity rises exponentially—, "E. imperialis" collect more dilute nectars, relative to their lapping bee counterparts, with sucrose concentrations between approximately 30 to 40%. During the actual ingestion, the glossa of "E. imperialis" is generally fully extended and stationary, stretching 6 mm beyond the apical end of the feeding tube formed by the galeae and the labial palps. Therefore, the shift in capillary-based lapping to suction feeding for "E. imperialis", although decreasing nectar sugar concentration, maximizes the rate of energy intake for each individual bee.
Immunoprecipitation
Proponents of magnetic beads claim that the beads exhibit a faster rate of protein binding over agarose beads for immunoprecipitation applications, although standard agarose bead-based immunoprecipitations have been performed in 1 hour. Claims have also been made that magnetic beads are better for immunoprecipitating extremely large protein complexes because of the complete lack of an upper size limit for such complexes, although there is no unbiased evidence stating this claim. The nature of magnetic bead technology does result in less sample handling due to the reduced physical stress on samples of magnetic separation versus repeated centrifugation when using agarose, which may contribute greatly to increasing the yield of labile (fragile) protein complexes. Additional factors, though, such as the binding capacity, cost of the reagent, the requirement of extra equipment and the capability to automate IP processes should be considered in the selection of an immunoprecipitation support.
Magnetofection
The magnetic nanoparticles are made of iron oxide, which is fully biodegradable, coated with specific cationic proprietary molecules varying upon the applications. Their association with the gene vectors (DNA, siRNA, ODN, virus, etc.) is achieved by salt-induced colloidal aggregation and electrostatic interaction. The magnetic particles are then concentrated on the target cells by the influence of an external magnetic field generated by magnets. The cellular uptake of the genetic material is accomplished by endocytosis and pinocytosis, two natural biological processes. Consequently, membrane architecture and structure stays intact, in contrast to other physical transfection methods that damage the cell membrane.
Bee learning and communication
Experiments by James Gould suggest that honey bees may have a cognitive map for information they have learned, and utilize it when foraging. In an experimental demonstration, Gould lured some bees to a dish of artificial nectar, then gradually moved it farther from the hive. He marked the trained bees, placed them in a darkened jar, and relocated them to a spot where the dish could not be seen but the hive was still visible. When released one by one, the bees appeared disoriented for a few seconds, then flew directly to the dish, 73 of 75 bees reaching it in about 28 seconds. They apparently accomplished this feat by devising a new flight path based on a cognitive map of visible landmarks.
Earth's magnetic field
Humans have used compasses for direction finding since the 11th century A.D. and for navigation since the 12th century. Although the magnetic declination does shift with time, this wandering is slow enough that a simple compass remains useful for navigation. Using magnetoreception various other organisms, ranging from some types of bacteria to pigeons, use the Earth's magnetic field for orientation and navigation.