Clumping is a behavior in an organism, usually sessile, in which individuals of a particular species group close to one another for beneficial purposes. Clumping can be caused by the abiotic environment surrounding an organism. Barnacles, for example, group together on rocks that are exposed for the least amount of time during the low tide. [1] Usually, clumping in sessile animals starts when one organism binds to a hard substrate, such as rock, and other members of the same species attach themselves afterwards. [2] Herbivorous snails are known to clump around where sufficient algae are present. [1] The clumping of mussels (shown right) has been found to be influenced by competition with other species. The mussels attach themselves by byssal threads to potential competitors for space. [3]
Clumping and increased locomotion has been found to occur with organisms such as blue mussels (Mytilus edulis) due to risks from predators such as the European lobster ( Homarus gammarus ). Trade-offs exist with clumping such as decreased growth and less reproductive activity from mussels clumping together due to predation. However, there are also benefits obtained, such as decreased mortality from predation and adverse weather conditions, from clumping. [4]
Clumping has been practiced by bivalve organisms from the times of the fossil record, and the trade-offs between living quite an aggregated lifestyle. Predators such as the gastropod Nucella lamellosa utilize drilling techniques in order to hunt prey such as the blue mussels, and the latter's clumping strategies results in significantly less drilling frequency overall. However, the average drilling placement and variation by the gastropod did not show variation as a result of clumping. [5]
Measuring clumped populations of organisms in nature can prove challenging at times for researchers. Quadrat sampling, a favored method by ecologists to study the density of populations, is not as effective with criteria such as those groups that are clumped. Other methods instead can be utilized to measure clumped populations, such as the line-intercept method which is more popular with organisms that can be studied and identified before they move. The reasoning behind organisms clumping revolve around resources being restrained in smaller regions within larger ones and select organisms forming social groups. The funnel-web spider ( Agelenopsis aperta ) at smaller scales are evenly distributed in their habitats, but are a clumped species on larger scales. The reasoning for this is two-fold. Firstly, these types of spiders prefer environments with the ability to attract insect prey and have favorable thermal properties. Secondly, there is a limited space for spiders to establish their websites, and competition for these spaces is substantial. However, on a macro scale, most organisms actually have clumped distributions due to their habitats not being eventually distributed over extensive areas. [6] Similar trends are seen with other species of spiders. Stegodyphus lineatus sees disadvantages no matter what other parameters exist when feeding in large groups. Otherwise, these types of spiders were able to survive in close proximity most effectively when they were of approximate equal size. The size of groups also played a role in the ability of these spiders to live. [7]
The practice of clumping occurs at both the macro and micro level for organisms. Closely tied to the endosymbiotic theory, there exists significant evidence that single-celled organisms in the distant past evolved and combined with other organisms to create complex multi-cellular lifeforms that make up much of life in the present. This was despite the fact that these single-celled organisms were capable of sustaining themselves and reproducing to create future generations. Nevertheless, this occurrence is considered to be a major transition in the evolution of life. The benefits of these multi-cellular lifeforms forming include further advances in efficiency to already existing ways that single-celled organisms cooperated; the creation of extracellular "public goods" is an example of organisms gaining from clumping. However, cooperation could still evolve and coexist alongside clumping as a strategy for organisms. As genetic similarity strengthened between organisms that clumped, both "public goods" production and clumping itself became more prevalent and easier to accomplish in the case of the latter. In addition, just small changes in genetic similarity can cause major shifts the outcome of evolution for organisms, such as increased output of vital materials for survival and growth. Clumping can be impeded when the number of organisms that benefits must be shared with increases, but stimulated when those organisms are more related to one another. [8]
Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation and parasitoidism. It is distinct from scavenging on dead prey, though many predators also scavenge; it overlaps with herbivory, as seed predators and destructive frugivores are predators.
Mussel is the common name used for members of several families of bivalve molluscs, from saltwater and freshwater habitats. These groups have in common a shell whose outline is elongated and asymmetrical compared with other edible clams, which are often more or less rounded or oval.
Aurelia aurita is a species of the genus Aurelia. All species in the genus are very similar, and it is difficult to identify Aurelia medusae without genetic sampling; most of what follows applies equally to all species of the genus.
The blue mussel, also known as the common mussel, is a medium-sized edible marine bivalve mollusc in the family Mytilidae, the mussels. Blue mussels are subject to commercial use and intensive aquaculture. A species with a large range, empty shells are commonly found on beaches around the world.
A tide pool or rock pool is a shallow pool of seawater that forms on the rocky intertidal shore. These pools typically range from a few inches to a few feet deep and a few feet across. Many of these pools exist as separate bodies of water only at low tide, as seawater gets trapped when the tide recedes. Tides are caused by the gravitational pull of the sun and moon. A tidal cycle is usually about 25 hours and consists of one or two high tides and two low tides.
Anti-predator adaptations are mechanisms developed through evolution that assist prey organisms in their constant struggle against predators. Throughout the animal kingdom, adaptations have evolved for every stage of this struggle, namely by avoiding detection, warding off attack, fighting back, or escaping when caught.
Optimal foraging theory (OFT) is a behavioral ecology model that helps predict how an animal behaves when searching for food. Although obtaining food provides the animal with energy, searching for and capturing the food require both energy and time. To maximize fitness, an animal adopts a foraging strategy that provides the most benefit (energy) for the lowest cost, maximizing the net energy gained. OFT helps predict the best strategy that an animal can use to achieve this goal.
The Jonah crab is a marine brachyuran crab that inhabits waters along the east coast of North America from Newfoundland to Florida. Jonah crabs possess a rounded, rough-edged carapace with small light spots, and robust claws with dark brown-black tips. The maximum reported carapace width for males is 222 mm, while females rarely exceed 150 mm. It is the closest relative to the European brown crab in the Western Atlantic.
Stegodyphus lineatus is the only European species of the spider genus Stegodyphus. Male S. lineatus can grow up to 12 mm long while females can grow up to 15 mm. The colour can range from whitish to almost black. In most individuals the opisthosoma is whitish with two broad black longitudinal stripes. Males and females look similar, but the male is generally richer in contrast and has a bulbous forehead. The species name refers to the black lines on the back of these spiders. S. lineatus is found in the southern Mediterranean region of Europe and as far east as Tajikistan.
The California mussel is a large edible mussel, a marine bivalve mollusk in the family Mytilidae.
Marine larval ecology is the study of the factors influencing dispersing larvae, which many marine invertebrates and fishes have. Marine animals with a larva typically release many larvae into the water column, where the larvae develop before metamorphosing into adults.
Mobbing in animals is an antipredator adaptation in which individuals of prey species mob a predator by cooperatively attacking or harassing it, usually to protect their offspring. A simple definition of mobbing is an assemblage of individuals around a potentially dangerous predator. This is most frequently seen in birds, though it is also known to occur in many other animals such as the meerkat and some bovines. While mobbing has evolved independently in many species, it only tends to be present in those whose young are frequently preyed upon. This behavior may complement cryptic adaptations in the offspring themselves, such as camouflage and hiding. Mobbing calls may be used to summon nearby individuals to cooperate in the attack.
Bioadhesives are natural polymeric materials that act as adhesives. The term is sometimes used more loosely to describe a glue formed synthetically from biological monomers such as sugars, or to mean a synthetic material designed to adhere to biological tissue.
The Chilean mussel or Chilean blue mussel is a species of blue mussel native to the coasts of Chile from Biobío Region to Cape Horn. Today genomic evidence confirmed that the native Chilean blue mussel is genetically distinct from the Northern Hemisphere M. edulis, M. galloprovincialis and M. trossulus and also genetically different from Mytilus platensis", the other species of smooth shelled mussel from Southamerica.
Mytilus is a cosmopolitan genus of medium to large-sized edible, mainly saltwater mussels, marine bivalve molluscs in the family Mytilidae.
Sessility is the biological property of an organism describing its lack of a means of self-locomotion. Sessile organisms for which natural motility is absent are normally immobile. This is distinct from the botanical concept of sessility, which refers to an organism or biological structure attached directly by its base without a stalk.
Nucella emarginata, common name the emarginate dogwinkle, is a species of medium-sized predatory sea snail, a marine gastropod mollusk in the family Muricidae, the murex snails or rock snails.
Stegodyphus sarasinorum, also known as the Indian cooperative spider, is a species of velvet spider of the family Eresidae. It is native to India, Sri Lanka, Nepal, and Myanmar. This spider is a social spider that exhibits communal predation and feeding, where individuals live in large cooperatively built colonies with a nest or retreat constructed of silk woven using leaves, twigs, and food carcasses, and a sheet web for prey capture.
Matriphagy is the consumption of the mother by her offspring. The behavior generally takes place within the first few weeks of life and has been documented in some species of insects, nematode worms, pseudoscorpions, and other arachnids as well as in caecilian amphibians.
Stegodyphus dumicola, commonly known as the African social spider, is a species of spider of the family Eresidae or the velvet spider family. It is native to Central and southern Africa. This spider is one of three Stegodyphus spiders that lives a social lifestyle. This spider has been studied living in large natal colonies in large, unkempt webs. Each colony is composed mainly of females, where a minority act as reproducers, and a majority remain childless and take care of the young. Males live a shorter lifespan and will largely remain in the natal nest throughout its life. Females are known for extreme allomaternal care, since all females, even unmated virgin females will take care of the young until they are eventually consumed by the brood.