Gammarus lacustris is an aquatic amphipod.
| Gammarus lacustris | |
|---|---|
 | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Malacostraca |
| Superorder: | Peracarida |
| Order: | Amphipoda |
| Family: | Gammaridae |
| Genus: | Gammarus |
| Species: | G. lacustris |
| Binomial name | |
| Gammarus lacustris G. O. Sars, 1863 | |
Gammarus lacustris is semi-transparent and lacks a webbed tail. It may be colorless, brown, reddish or bluish in color, depending on the local environment. It has seven abdominal segments, a fused cephalothorax, and two pairs of antennae. Unlike other crustaceans, amphipods lack carapaces and have laterally compressed bodies. Gammarids are referred to as scuds or sideswimmers. G. lacustris resembles a freshwater shrimp.
The female carries eggs in a brood pouch on its ventral side. G. lacustris in higher elevations were more likely to have fewer but larger eggs than those living at lower elevations. [1] G. lacustris undergoes several molts and juveniles resemble the adult.
Gammarus lacustris plays an important role in many of the freshwater ecosystems that it inhabits. It is a detritivore and may also consume algae, mainly diatoms. [1] It is considered an indicator species for the overall health and stability of the ecosystem. G. lacustris can also inhabit a wide array of environments, ranging from low altitude calcium-rich lakes to high altitude, cold, and calcium-poor lakes. This influences its biology: at low altitudes, it is known to die after first reproduction, but in colder waters, it lives to reproduce repeatedly. [2]
In many species feeding behaviour is affected by temperature, i.e. the amount of food consumed often increases at warmer temperatures. [3] However, when G. lacustris feeds on three different parasite species (Diplostomum spp., Apatemon spp. and Trichobilharzia spp.) no such effect of temperature on feeding is seen. [4]
As a small aquatic invertebrate G. lacustris is an important food source for many organisms. Birds, fishes, and some insects are known to prey upon G. lacustris. As many other species of small invertebrates, it serves as an intermediate host for several parasite species (e.g. Pomphorhynchus laevis ). [5] [6] G. lacustris typically shows photophobic behaviour, but when parasitized this can be altered to photophilic behaviour when infected by Pomphorhynchus laevis, [6] which is a host manipulation parasite, like many others. [5] [7] Parasites can affect the diel migration of G. lacustris, making it more visible and susceptible to predation most likely aiding parasite transmission. [5] [7] [8] [9] More mature parasites have greater effects on hosts. [10]
Gammarus lacustris has been noted in northwestern Europe, Russia, and North America. [1] [11] Its precise range has yet to be defined. It can be found in shallow or deep lakes and in slow-moving rivers. It is more abundant in fishless lakes than in those with fish. Its distribution follows the thermocline in the water. [11]
Acanthocephala is a group of parasitic worms known as acanthocephalans, thorny-headed worms, or spiny-headed worms, characterized by the presence of an eversible proboscis, armed with spines, which it uses to pierce and hold the gut wall of its host. Acanthocephalans have complex life cycles, involving at least two hosts, which may include invertebrates, fish, amphibians, birds, and mammals. About 1420 species have been described.
Nematomorpha are a phylum of parasitoid animals superficially similar to nematode worms in morphology, hence the name. Most species range in size from 50 to 100 millimetres, reaching 2 metres (79 in) in extreme cases, and 1 to 3 millimetres in diameter. Horsehair worms can be discovered in damp areas, such as watering troughs, swimming pools, streams, puddles, and cisterns. The adult worms are free-living, but the larvae are parasitic on arthropods, such as beetles, cockroaches, mantises, orthopterans, and crustaceans. About 351 freshwater species are known and a conservative estimate suggests that there may be about 2000 freshwater species worldwide. The name "Gordian" stems from the legendary Gordian knot. This relates to the fact that nematomorphs often coil themselves in tight balls that resemble knots.
Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson characterised parasites as "predators that eat prey in units of less than one". Parasites include single-celled protozoans such as the agents of malaria, sleeping sickness, and amoebic dysentery; animals such as hookworms, lice, mosquitoes, and vampire bats; fungi such as honey fungus and the agents of ringworm; and plants such as mistletoe, dodder, and the broomrapes.
Parasitology is the study of parasites, their hosts, and the relationship between them. As a biological discipline, the scope of parasitology is not determined by the organism or environment in question but by their way of life. This means it forms a synthesis of other disciplines, and draws on techniques from fields such as cell biology, bioinformatics, biochemistry, molecular biology, immunology, genetics, evolution and ecology.
Amphipoda is an order of malacostracan crustaceans with no carapace and generally with laterally compressed bodies. Amphipods range in size from 1 to 340 millimetres and are mostly detritivores or scavengers. There are more than 9,900 amphipod species so far described. They are mostly marine animals, but are found in almost all aquatic environments. Some 1,900 species live in fresh water, and the order also includes the terrestrial sandhoppers such as Talitrus saltator and Arcitalitrus sylvaticus.
Plasmodium gallinaceum is a species of the genus Plasmodium that causes malaria in poultry.
An obligate parasite or holoparasite is a parasitic organism that cannot complete its life-cycle without exploiting a suitable host. If an obligate parasite cannot obtain a host it will fail to reproduce. This is opposed to a facultative parasite, which can act as a parasite but does not rely on its host to continue its life-cycle. Obligate parasites have evolved a variety of parasitic strategies to exploit their hosts. Holoparasites and some hemiparasites are obligate.
Gammarus pulex is a species of amphipod crustacean found in fresh water across much of Europe. It is a greyish animal, growing to 21 mm (0.83 in) long.
Thiothrix is a genus of filamentous sulfur-oxidizing bacteria, related to the genera Beggiatoa and Thioploca. They are usually Gram-negative and rod-shaped. They form ensheathed multicellular filaments that are attached at the base, and form gonidia at their free end. The apical gonidia have gliding motility. Rosettes of the filaments are not always formed but are typical. Sulfur is deposited in invaginations within the cell membrane.
Gammarus roeselii is a species of freshwater amphipod native to Europe.
Pomphorhynchus laevis is an endo-parasitic acanthocephalan worm, with a complex life cycle, that can modify the behaviour of its intermediate host, the freshwater amphipod Gammarus pulex. P. laevis does not contain a digestive tract and relies on the nutrients provided by its host species. In the fish host this can lead to the accumulation of lead in P. laevis by feeding on the bile of the host species.
Schistocephalus solidus is a tapeworm of fish, fish-eating birds and rodents. This hermaphroditic parasite belongs to the Eucestoda subclass, of class Cestoda. This species has been used to demonstrate that cross-fertilization produces a higher infective success rate than self-fertilization.
Pomphorhynchidae is a family of parasitic worms from the order Echinorhynchida.
Patricia G. Parker is a North American evolutionary biologist who uses molecular techniques to assess social structures, particularly in avian populations. Her interests have shaped her research in disease transmission and population size, particularly in regard to bird conservation. She received her B.S. in Zoology in 1975 and her Ph.D. in Behavioral Ecology in 1984, both from the University of North Carolina at Chapel Hill. From 1991 to 2000, Parker was an Assistant and Associate Professor in the Department of Evolution, Ecology, and Organismal Biology at Ohio State University. Since 2000, she is the Des Lee Professor of Zoological Studies at the University of Missouri–St. Louis.
Behavior-altering parasites are parasites with two or more hosts, capable of causing changes in the behavior of one of their hosts to enhance their transmission, sometimes directly affecting the hosts' decision-making and behavior control mechanisms. They do this by making the intermediate host, where they may reproduce asexually, more likely to be eaten by a predator at a higher trophic level which becomes the definitive host where the parasite reproduces sexually; the mechanism is therefore sometimes called parasite increased trophic facilitation or parasite increased trophic transmission. Examples can be found in bacteria, protozoa, viruses, and animals. Parasites may also alter the host behaviour to increase protection of the parasites or their offspring; the term bodyguard manipulation is used for such mechanisms.
Pasteuria is a genus of mycelial and endospore-forming, nonmotile gram-positive bacteria that are obligate parasites of some nematodes and crustaceans. The genus of Pasteuria was previously classified within the family Alicyclobacillaceae, but has since been moved to the family Pasteuriaceae.
Pleistophora mulleri (Pfeiffer) Georgev. 1929 is a parasite of the amphipod Gammarus duebeni celticus. The parasite targets the freshwater shrimp species and has shown higher rates of cannibalism, which in turn, affects biological communities and ecology.
Harrison's rule is an observation in evolutionary biology by Launcelot Harrison which states that in comparisons across closely related species, host and parasite body sizes tend to covary positively.
An aggregated distribution, commonly found among predators and parasites, is a highly uneven (skewed) statistical distribution pattern in which they collect or aggregate in regions, which may be widely separated, where their prey or hosts are at high density. This distribution makes sampling difficult and invalidates commonly-used parametric statistics. A similar pattern is found among predators that search for their prey.
Gammarus fossarum is a species complex of freshwater amphipod crustacean native to Europe. They are abundant members of the macroinvertebrate community, and also used as model organisms for ecotoxicology.
| Authority control databases: National |
|---|
