Letteratura scientifica selezionata sul tema "Predators fungi"

Carnivorous Nepenthes pitcher plants contain aquatic ecosystems within each fluid-filled pitcher. Communities of arthropods and microbes colonize pitcher pools, and some organisms are endemic to the pitcher habitat. Flies and mites are the most apparent colonizers, and together with numerous protists, fungi, and bacteria, they form a food web of predators, decomposers, and primary producers. Bacterial diversity and composition are correlated strongly with fluid pH. Closely related organisms co-occur within pitchers, suggesting that competition is not the primary structuring force of pitcher co

The book ends with a chapter devoted to discussing interactions between microbes and higher plants and animals. Symbiosis is sometimes used to describe all interactions, even negative ones, between organisms in persistent, close contact. This chapter focuses on interactions that benefit both partners (mutualism), or one partner while being neutral to the other (commensalism). Microbes are essential to the health and ecology of vertebrates, including Homo sapiens. Microbial cells outnumber human cells on our bodies, aiding in digestion and warding off pathogens. In consortia similar to the anae

Protists are involved in many ecological roles in natural environments, including primary production, herbivory and carnivory, and parasitism. Microbial ecologists have been interested in these single-cell eukaryotes since Antonie van Leeuwenhoek saw them in his stool and scum from his teeth. This chapter focuses on the role of protozoa (purely heterotrophic protists) and other protists in grazing on other microbes. Heterotrophic nanoflagellates, 3–5 microns long, are the most important grazers of bacteria and small phytoplankton in aquatic environments. In soils, flagellates are also importan

Population dynamics of plant species of coastal sand dunes is influenced directly, both above and below the soil surface, by a wide variety of organisms. Plants serve as sources of carbon and pathogens including viruses, insects, bacteria, fungi, birds, and mammals of various kinds. Some enhance plant performance while others have deleterious effects. Positive interactions include pollination of flowers by useful insects in return for nectar and pollen, nutrient acquisition from soil by mycorrhizal fungi in exchange for carbon and acquiring nitrogen (N) from N-fixing bacteria. In the history of co-evolution between plants and organisms over one hundred million years plants have developed many mechanisms to defend themselves from pathogens. Morphology may be altered by producing epicuticular waxes, developing trichomes over leaves, producing tough leaves with deposition of celluloses, lignin, suberin and callose, developing thorns on stems and branches or producing secondary plant metabolites that retard development, intoxicate or kill herbivorous insects. Herbivory may induce a plant to produce chemicals that signal to advertise the presence of insects feeding on them and attract parasites to reduce their numbers. Phenological escape is also employed, such as delay of leaf expansion during periods of insect abundance. Some indirect mechanisms of plant defence involve the use of insects such as ants for protection from other phytophagous insects. However, the predators have also evolved the ability to break down the defence mechanisms of the plant. For example, they may use phytochemicals for their own defence or as olfactory clues for feeding. In this chapter a brief account of organisms of the coastal dune communities, including species of the intertidal zone, scavengers of the sea coast, reptiles, birds, insects, mammals and their possible interactions with terrestrial vegetation is presented. For biological organisms of the seashore the intertidal zone is the most important for food and shelter. The sand-dwelling species of the seashore must be able to contend with four limiting factors: (i) rush of water from the approaching or receding high tide and pounding breakers, (ii) low salinity of the top surface of sand (iii) desiccation of surface by high winds and sunshine and (iv) extreme changes in temperature of topsoil.

<em>Abstract.</em>—During 1997–2000, chum salmon <em>Oncorhynchus keta </em>spawners and their predators and scavengers were observed in lower Kennedy Creek, a small south Puget Sound, Washington stream. Chum salmon occupy 5.2 km of main Kennedy Creek and a small tributary called Fiscus Creek. Spawning escapements within this stream averaged 39,000 fish annually during this study. Active spawning began in late October and was over by mid- December. Direct consumption of live and dead salmon was observed or inferred from animal signs over the spawning period. Salmon carcasses and tissue fragments could be found scattered along the streambed from October through March, and bones remained year round. Live spawners, carcass flesh, and eggs were consumed by 30 species of birds, mammals, invertebrates, and fungi, including 9 previously undocumented species. High carcass densities allowed selective feeding for some consumers and opportunistic feeding for others. Apparent preferences for eggs by several consumers suggested another important role for naturally spawning salmon. Varied thrush <em>Ixoreus naevius</em>, otter <em>Lutra canadensis</em>, and song sparrow <em>Melospiza melodia </em>showed preferences for salmon eggs, and a cougar <em>Felis concolor </em>killed live salmon and fed on them. Some consumers coordinate successive utilization of carcasses, such as the gull <em>Larus </em>spp., terrestrial beetle <em>Agyrtidae</em>, raccoon <em>Procyon lotor</em>, fly maggots, and mice. Water samples taken from the anadromous areas of these creeks and from the estuary in Totten Inlet showed elevated levels of dissolved ammonium, nitrate, and nitrite. Benefits to chum fry were inferred.

Soil organisms are fauna and flora that spend all or part of their life in the soil. They play a vital role in the maintenance of soil fertility through processes such as the accumulation of soil organic matter, soil aggregation, and the mineralization of organic matter which releases nutrients available to higher plants. Moreover, many antibiotics are produced from microorganisms isolated from soils. Soil fauna include macrofauna (> 2 mm in width, such as mice, earthworms, termites, and millipedes), through mesofauna (0.2-2 mm, such as collembola and mites), to microfauna (<0.2 mm, such as nematodes and protozoa). Soil flora include macroflora (such as the roots of higher plants), and microflora (such as algae, fungi, actinomycetes, and bacteria). The activities of soil fauna and flora are intimately related in what ecologists call a food chain or, more accurately, a food web. Higher plants play the role of primary producers by using water and energy from the sun, and carbon from atmospheric carbon dioxide to make organic molecules and living tissues. Soil organisms that eat live plants, such as mice or termites, are called herbivores. Most soil organisms, however, use the debris of dead tissues left by plants and animals (detritus) as their source of food, and are called detritivores. Soil organisms that consume live animals, such as centipedes, mites, spiders, or nematodes, are predators and are called carnivores. Some organisms that live off, but do not consume, other organisms are called parasites. Mycrophytic feeders are organisms that use microflora as their source of food, and include certain collembola, mites, termites, nematodes, and protozoa. The actions of soil fauna in the food web are both physical and chemical, while those of the microflora are mostly biochemical. The actions of mesofauna and macrofauna enhance the activities of the microflora in several ways. First, the chewing action fragments the litter to expose the more easily decomposed cell contents for microbial digestion. Second, the fragmented plant tissues are thoroughly mixed with microorganisms in the animal gut, where conditions are ideal for microbial action. Third, the mobile animals carry microorganisms with them and help them to disperse and find new food sources.

Decades of ill-agricultural practices associated with emerging risks of climatic changes have been degrading the ecosystem with immense stress on the soil health, crop productivity. Arbuscular mycorrhiza (AM) form advantageous symbiosis between plant roots and specialized soil fungi that is rampant in natural habitats. Studies show that the elevated AMF indicated good soil health, high crop turnouts benefiting the Agriculture and other industries. AMF dependent on plants for sugars, while offering benefits like intact binding of soil particles, biomass increase, improvement of water-holding capacity, replacement of harmful chemicals, increased intake of phosphorous, zinc and other nutrients, drought and salinity tolerance, carbon sequestering in soil and protection from nematodes and other predatory insects. AMF are best candidates as bio-fertilizers and this review will explore their beneficial interconnections.

Earthworm causes increase in availability of soil organic matter through degradation of dead matters by microbes, leaf litter and porocity of soil. Vermicompost is a non-thermophilic biodegradation process of waste organic material through the action of microorganism with earthworm. Vermicompost is rich in many nutrients including calcium, nitrates, phosphorus and soluble potassium, which are essentially required for plant growth. Different plant growth hormones like gibberellins, auxins and cytokinins are present in vermicompost, which has microbial origin. Nematodes are mostly small, colorless and microscopic organisms which remain under soil, fresh or marine water, plants or animals, and act as parasite in different conditions, while very few have direct effect on human. The nematodes which are parasitic on plants use plant tissues as their food. They have well developed spearing device, like a hypodermic needle called stylet. It is used to penetrate host cell membrane. Management of plant-parasitic-nematodes therefore is necessary and several means are adopted. Of which, use of bio-chemicals and organic compost have shown encouraging results and proved to be potential in suppressing the nematode population. Vermicompost plays an important role of soil fortification on growth characteristics, such as length, weight, root, shoot branches, number of leaves and metabolism of host plant against nematode infection. Vermicompost fortified plants showed increment in sugar, protein and lipid over untreated control. Increment of these metabolites helps treated plants to metabolically cope up the infection and promotes excessive plant growth. The vermicompost caused the mortality of nematodes by the release of nematicidal substances such as hydrogen sulfate, ammonia, and nitrite apart from promotion of the growth of nematode predatory fungi that attack their cysts. It favours rhizobacteria which produce toxic enzymes and toxins; or indirectly favors population of nematophagous microorganisms, bacteria, and fungi, which serve as food for predatory or omnivorous nematodes, or arthropods such as mites, which are selectively opposed to plant-parasitic nematodes.