User:Lauracadigan5/sandbox

Week 3: Article Evaluation
Everything included in the wikipedia article "Phagomimicry" is relevant to the topic, there is just a lack of information in the article. The only section present is a very brief definition of the behaviour. There is nothing distracting in the text. This article is of a neutral tone, there are no claims or frames that appear heavily biased towards one position. There are no view points that are over or underrepresented in the information given, but the lack of information is an underrepresentation of the topic. Additional information from sources such as or may be able to aid in adding additional information. The links all appear to work, and they support claims made in the article. Facts are referenced with appropriate and reliable references, such as from the Journal of Chemical Ecology, which is a neutral source. As more information is added, additional sources will need to be added and cited as well. There is no out of date information, but there is much missing. There is very little about this behaviour explained in this article. There is nothing in the talk page of this article. This article is a part of the wiki project ecology, and the wiki project evolutionary biology. It is rated of low importance. We have not discussed this topic in class.

Week 6: Draft
This draft article will start with a broad overview and definition of phagomimicry, then move into more specific subsections. This article will include some photos to aid in describing this behaviour.

Phagomimicry (heading 1):
 * This section will give an overview to this behaviour, what species display this behaviour (and what species display a similar behaviour), and a brief description of the ink composition.

Inking Behaviour (heading 2): Chemical Composition (heading 3): Physical Properties (heading 4): See Also (heading 5):
 * The other subsections will be briefly described
 * This sub section will describe the inking behaviour of sea hares (i.e. what provokes the ink secretion and how sea hares behave during and after the ink secretion).
 * This section will also provide a description of the opaline gland (used in ink production)
 * This section will describe the chemical composition of the ink, including information about the high amino acid concentration and the effect this has on predators.
 * The ink released by sea hares has two components secreted from two different glands. The ink gland secrets a deep purple ink, and the opaline gland secretes a viscous milky white liquid.
 * Free amino acids (FAAs) and ammonium are two main ingredients in the ink secretion, these serve as chemosensory stimulants to predators and aid in the escape of the sea hares.
 * In phagomimicry, the FAA concentration has to be similar to that found in food, this in turn is able to trick predators into thinking that they are eating prey when in fact it is just an ink secretion.
 * This section will describe the physical properties of the ink such as its particle size, and density.
 * It will also include how the physical properties allow for the escape of sea hares from predation.
 * This section will discuss the coevolution of this behaviour with other ink secretion behaviour in closely related species.

Phagomimicry
Phagomimicry is a defensive behaviour of sea hares, in which the animal ejects a mixture of chemicals, which mimic food, and overwhelm the senses of their predator, giving the sea-hare a chance to escape. The typical defence response of the sea hare to a predator is to release two chemicals - ink from the ink gland and opaline from the opaline gland. While ink creates an dark, diffuse cloud in the water which disrupts the sensory perception of the predator by acting as a smokescreen and as a decoy, the opaline, which affects the senses dealing with feeding, causes the predator to instinctively attack the cloud of chemicals as if it were indeed food. This ink is able to mimic food by having a high concentration of amino acids and other compounds that are normally found in food, and the attack behaviour of the predator allows the sea-hares the opportunity to escape.

Inking Behaviour
The inking behaviour exhibited in phagomimicry is in response to predator threat. Sea hares have many natural predators such as starfish, lobsters, and other crustaceans. When threatened by a predator, phagomimicry behaviour begins. An ink solution is released from both the opaline and ink glands individually, then the compounds mix in the mantle of the sea hare to form the ink mixture. When ink is released it creates a smoke-screen like defense mechanism allowing the sea hares time to escape while also affecting the olfactory and gustation senses of their predator. Predators are tricked into thinking that they have captured their prey due to the specific chemical composition of the ink released. This induces feeding behaviours in the predator, and again gives the sea hares a better chance of escaping predation.

The opaline gland is a structure resembling a bundle of grapes attached to a central canal which is composed of epithelial cells. Synthesis of the opaline substance happens in the opaline vesicles themselves, as there are only opaline vesicles and muscle cells in the opaline gland. The gland is innervated by three separate motor neurons, and is composed of single large cells and vesicle cells, all of which have enlarged nucleus. These cells are inclosed in an external layer of muscle. When a sensory neuron detects a predator threat, dopamine is released onto one of the three motor neurons. The dopamine release causes a gland contraction, which then causes the expulsion of the opaline substance.

The ink gland is smaller in size than the opaline gland, and is composed of two cell types: Rough endoplasmic recticlum (RER) and granulate cells. The cells are surrounded by a layer of muscle, to contraction and expelling their contents. The RER is the formation site of the anti-predator protein, the granulate cells are for extra pigment storage. Pigment is dependent on the amount of red algae available to the sea hares, the higher the red algal consumption, the darker the colour of their ink. This mixing can causes another chain of reactions between the compounds that have further implications on the effect that the ink secretion has on predators.

Ink Chemical Composition
Both the opaline and ink gland secrete different substances that when mixed together form the ink released during phagomimicry. The secretion is very acidic (ink having a pH of 4.9 and opaline having a pH of 5.8) and contains high levels of bioactive molecules that can serve as feeding stimulants, feeding deterrents, and aversive compounds. Feeding stimulants can be found in both the ink and opaline secretions in the form of amino acids (such as lysine and arginine), and serve to trick predators into thinking that the ink secretion is a food source. To induce the aversive feeding effects on predators the ink contains a compound from the opaline gland produced from the oxidation of L -lysine, which is then mixed in the mantle with the L -amino acid oxidase from the ink gland. Together this compound, called escapin is secreted in the ink, and is a feeding deterrent. The ink secretion can have a long-lasting effect on predators as chemical phagomimics can cause chemo-mechanosensory stimulation which overwhelms the sensory system and leads to confusion and eventually the cession of the attack.

Physical Properties of Ink
The ink released from the ink gland is dark purple in colour, the colour depends on the type of algae consumed by the sea-hare. The opaline ink is white in colour, and when it mixes with the ink gland ink they form a compound that suspends itself in the water (polidisperse suspension), creating a smoke-screen defence mechanism. The particle density of the ink is similar to that of species such as cuttlefish, the particles range in size from 80-150nm, with a density of 1.27cm -3, which allows for the inks suspension in water.

See Also
 * cuttlefish
 * cephalopod ink

Peer review: Jessica O'Dea
The introduction provides a clear and comprehensive description of phagomimicry. I like that you explained not only the chemical composition of ink but also how the composition serves to benefit escape function. I think the article could be improved by expanding on the physical properties of ink secretion and including how they function to improve an animals chance of escaping predator.

References: