Types Parasitism

1 types

1.1 evolutionary strategies
1.2 classification

1.2.1 ectoparasites
1.2.2 endoparasites
1.2.3 mesoparasites
1.2.4 parasitoids
1.2.5 hyperparasites
1.2.6 social parasites
1.2.7 adelpho-parasites
1.2.8 sexual parasites


1.3 parasitic plants
1.4 parasitic fungi
1.5 parasitic bacteria
1.6 viruses

types

the entomologist e. o. wilson has characterised parasites predators eat prey in units of less 1 . within scope many possible ways of life. parasites classified in variety of different overlapping schemes, based on interactions hosts , on life cycles. obligate parasite totally dependent on host complete life cycle, while facultative parasite not. direct parasite has 1 host while indirect parasite has multiple hosts. indirect parasites, there definitive host , intermediate host.

evolutionary strategies

micropredator, typical parasite, parasitoid, , predator strategies compared. interactions hosts form continuum. micropredation , parasitoidy considered evolutionary strategies within parasitism.



acrodactyla quadrisculpta parasitoid wasp, host spider. parasitoids parasites kill hosts.

there 6 major evolutionary strategies within parasitism. these apply parasites hosts plants animals:

these strategies successful parasitism adaptive peaks; many intermediate strategies possible, organisms in many different groups have consistently converged on these six, evolutionarily stable.

classification

human head lice (pediculus humanus capitis) obligate ectoparasites.



ectoparasites

parasites live on outside of host, either on skin or outgrowths of skin, called ectoparasites. directly transmitted between hosts. examples include lice, fleas, , mites.

endoparasites

schistosoma mansoni obligate endoparasite of human blood vessels, causing schistosomiasis (bilharzia).

those live inside host, including parasitic worms (helminths), called endoparasites. endoparasites can exist in 1 of 2 forms: intercellular parasites (inhabiting spaces in host s body) or intracellular parasites (inhabiting cells in host s body). coinfection multiple parasites common.

intracellular parasites, such pathogenic (disease-causing) protozoa, bacteria or viruses, tend rely on third organism, carrier or vector, transmit them host.

autoinfection infection of primary host parasite, particularly helminth, in such way complete life cycle of parasite happens in single organism, without involvement of host. can occur intestinal parasite strongyloides stercoralis. strongyloidiasis involves premature transformation of noninfective larvae infective larvae, can penetrate intestinal mucosa (internal autoinfection) or skin of perineal area (external autoinfection).

mesoparasites

those parasites living in intermediate position, being half-ectoparasites , half-endoparasites, called mesoparasites. example, cod worm lernaeocera branchialis invades gill tissue of host fish, grows tubelike structure cuts through body tissues until reaches fish s heart, through robs host of blood. rear end of parasite remains outside, can scatter eggs water.

a parasitoidal wasp ovipositing body of spotted alfalfa aphid


parasitoids

a parasitoid sooner or later kills prey, form of parasitism close predation. idiobiont parasitoid wasps sting prey on capture, either killing them outright or paralyzing them immediately. prey carried nest, egg laid on or in it, , parasitoid develops rapidly. koinobiont parasitoid wasps lay eggs in young hosts, larvae, allowed go on growing, host , parasitoid develop extended period. koinobionts regulate host s development hormonally, example preventing pupating or making moult whenever parasitoid ready moult.

hyperparasites

a hyperparasitoid chalcid wasp (pteromalidae) on cocoons of host, braconid wasp (microgastrinae), koinobiont parasitoid of lepidoptera

a hyperparasite or epiparasite feeds on parasite, exemplified protozoan living in helminth parasite. term used more loosely refer parasitoids hosts either parasites or parasitoids. hyperparasitoids may facultative or obligate, , young may develop inside or outside host s body, larva.

social parasites

the large blue butterfly mimic , social parasite of ants.

social parasites take advantage of interactions between members of social organisms such ants, termites, , bumblebees. examples include large blue butterfly, phengaris arion. larvae employ mimicry parasitize species of ants, bombus bohemicus, bumblebee invades hives of other species of bee , takes on reproduction, young raised host workers, , melipona scutellaris, eusocial bee virgin queens escape killer workers , invade colony without queen. extreme example of social parasitism ant species tetramorium inquilinum of alps, lives exclusively on backs of other species of tetramorium host ants. tiny , weakened bodies, have evolved single task: holding on host, since if fall off, die.

in kleptoparasitism (from greek κλέπτης (kleptes), thief), parasites appropriate food gathered host. example brood parasitism practiced cowbirds, whydahs, cuckoos, , black-headed ducks not build nests of own , leave eggs in nests of other species. host behaves babysitter raise young own. if host removes cuckoo s eggs, cuckoos return , attack nest compel host birds remain subject parasitism.

intraspecific social parasitism may occur, in parasitic nursing, individual young take milk unrelated females. in wedge-capped capuchins, higher ranking females take milk low ranking females without reciprocation. high ranking females benefit @ expense of low ranking females.

parasitism can take form of isolated cheating or exploitation among more generalized mutualistic interactions. example, broad classes of plants , fungi exchange carbon , nutrients in common mutualistic mycorrhizal relationships; however, plant species known myco-heterotrophs cheat taking carbon fungus rather donating it.

adelpho-parasites

the male anglerfish ceratias holboelli lives tiny sexual parasite permanently attached below female s body.

an adelpho-parasite (from greek αδελφός (adelphos), brother) parasite in host species closely related parasite, being member of same family or genus. example of citrus blackfly parasitoid, encarsia perplexa, unmated females of may lay haploid eggs in developed larvae of own species. these result in production of male offspring. marine worm bonellia viridis has similar reproductive strategy, although larvae planktonic.

sexual parasites


cuscuta (a dodder), stem holoparasite, on acacia tree

in many animals, males smaller females. in species of anglerfish, such ceratias holboelli, males small have become sexual parasites, wholly dependent on females of own species survival, , unable fend themselves. female nourishes male , protects him predators, while male gives nothing except sperm female needs produce next generation.

parasitic plants

a parasitic plant derives or of nutritional requirements living plant. make 1% of angiosperms , in every biome in world. parasitic plants have modified roots, named haustoria (singular: haustorium), penetrate host plants, connecting them conductive system – either xylem, phloem, or both. provides them ability extract water , nutrients host. parasitic plants classified depending on parasitic plant latches onto host , amount of nutrients requires. parasitic plants able locate host plants detecting chemicals in air or soil given off host shoots or roots, respectively. 4,500 species of parasitic plant in approximately 20 families of flowering plants known.

species within orobanchaceae (broomrapes) of economically destructive species on earth. species of striga (witchweeds) estimated cost billions of dollars year in crop yield loss annually, infesting on 50 million hectares of cultivated land within sub-saharan africa alone. striga infects both grasses , grains, including corn, rice , sorghum, undoubtedly of important food crops. orobanche threatens wide range of important crops, including peas, chickpeas, tomatoes, carrots, , varieties of genus brassica (cabbages). yield loss orobanche can reach 100%; despite extensive research, no method of control has been entirely successful.

the honey fungus, armillaria mellea, parasite of trees, , saprophyte feeding on trees has killed.


parasitic fungi

parasitic fungi derive or of nutritional requirements plants, other fungi, or animals, , unlike mycorrhizal fungi have mutualistic relationship host plants, pathogenic. example, honey fungi in genus armillaria grow in roots of wide variety of trees, , kill them. continue live in dead wood, feeding saprophytically.

borrelia burgdorferi, bacterium causes lyme disease, transmitted ixodes ticks.


parasitic bacteria

many bacteria parasitic, though since result infection , disease, leading death, thought of pathogens instead. parasitic bacteria extremely diverse, , infect hosts variety of routes. give few examples, bacillus anthracis, cause of anthrax, spread contact infected domestic animals; bacillus s spores, can survive years outside body, can enter host through abrasion or may inhaled. borrelia, cause of lyme disease , relapsing fever, transmitted vector, ticks of genus ixodes, diseases reservoirs in animals such deer. campylobacter jejuni, cause of severe enteritis (gut inflammation), spread fecal-oral route animals, or eating insufficiently cooked poultry, or contaminated water. haemophilus influenzae, agent of bacterial meningitis , respiratory tract infections such influenza , bronchitis, transmitted droplet contact. treponema pallidum, cause of syphilis, spread sexual intercourse.

enterobacteria phage t4 bacteriophage virus. infects host, escherichia coli, injecting dna through tail, attaches bacterium s surface.


viruses

viruses obligate intracellular parasites, characterized extremely limited biological function, point where, while evidently able infect other organisms bacteria , archaea animals, plants , fungi, unclear whether can described living. viruses consist of strip of genetic material (dna or rna), covered in protein coat , lipid envelope. lack usual machinery of cell such enzymes, relying entirely on host cell s ability replicate dna , synthesise proteins. viruses bacteriophages, infecting bacteria, , possible viruses both extremely ancient, being @ least old first cells, , polyphyletic, having evolved several entirely unrelated ancestors.