Toxoplasma gondii is best known as the parasite that may lurk in a cat's litter box. Nearly a third of the world's population is believed to live with a chronic Toxoplasma infection. It's of greatest concern, however, to ...
Cell & Microbiology
Jan 24, 2020
4
297
Parasitic weeds are among the world's most economically damaging agricultural pests. They use an organ called the haustorium to build connections with host plants and draw nutrients from them.
Ecology
Jan 15, 2020
0
5
The cat parasite Toxoplasma gondii is known to cause infected rodents to lose their fear of feline predators, which makes the mice easier to catch. Predators then spread the parasites through their feces. But this so-called ...
Cell & Microbiology
Jan 14, 2020
13
178
A breakthrough by ecologists at the Scripps Institution of Oceanography has implications for multiple fields of biology.
Plants & Animals
Jan 08, 2020
0
107
The American coot is a somewhat drab water bird with gray and black feathers and a white beak, common in wetlands throughout North America. Coot chicks, however, sport outrageously bright orange and red feathers, skin, and ...
Plants & Animals
Dec 30, 2019
1
569
Malaria parasites transform healthy red blood cells into rigid versions of themselves that clump together, hindering the transportation of oxygen. The infectious disease affects more than 200 million people around the world ...
Cell & Microbiology
Dec 27, 2019
0
17
When controlling mosquitoes that spread malaria, gene drives, which force genetic changes to proliferate in a population, are faster and more efficient than simply releasing mosquitoes that are immune to the parasite, according ...
Biotechnology
Dec 19, 2019
1
7
Researchers have discovered a novel parasitic gene in fruit flies that is responsible for destroying the eggs in the ovaries of their daughters.
Plants & Animals
Dec 17, 2019
0
3
A parasitic plant has found a way to circumvent an evolutionary arms race with the host plants from which it steals nutrients, allowing the parasite to thrive on a variety of agriculturally important plants. The parasite ...
Evolution
Dec 17, 2019
0
110
A parasitic wasp has shown tremendous potential attacking and controlling spotted wing drosophila—an invasive, destructive fruit fly that costs Oregon growers close to a billion dollars a year, Oregon State University researchers ...
Ecology
Dec 11, 2019
0
99
Parasitism is a type of symbiotic relationship between two different organisms where one organism, the parasite, takes favor from the host, sometimes for a prolonged time. In general, parasites are much smaller than their hosts, show a high degree of specialization for their mode of life, and reproduce more quickly and in greater numbers than their hosts. Classic examples of parasitism include interactions between vertebrate hosts and diverse animals such as tapeworms, flukes, the Plasmodium species, and scabs. Parasitism is differentiated from parasitoidism, a relationship in which the host is always killed by the parasite such as moths, butterflies, ants, flies and others.
The harm and benefit in parasitic interactions concern the biological fitness of the organisms involved. Parasites reduce host fitness in many ways, ranging from general or specialized pathology (such as castration), impairment of secondary sex characteristics, to the modification of host behaviour. Parasites increase their fitness by exploiting hosts for food, habitat and dispersal.
Although the concept of parasitism applies unambiguously to many cases in nature, it is best considered part of a continuum of types of interactions between species, rather than an exclusive category. Particular interactions between species may satisfy some but not all parts of the definition. In many cases, it is difficult to demonstrate that the host is harmed. In others, there may be no apparent specialization on the part of the parasite, or the interaction between the organisms may be short-lived. In medicine, only eukaryotic organisms are considered parasites, with the exclusion of bacteria and viruses. Some branches of biology, however, regard members of these groups as parasitic.[citation needed]
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