The diversity of soil life is considerable, so it should not be surprising to learn that there are fungi that have lassos like cowboys taking down steers at a rodeo. Or that other fungi create nets to capture food like fishermen. These fungi have evolved to create traps when a.) their decayed food source is low in nitrogen and b.) their prey is within “sniffing” distance. The prey for these “occasional predators” are nematodes, small worms commonly found in the soil rhizosphere (shallow area near plant roots).
These nematophageous (nee-mat-o-fa-jus) fungi can detect (sniff) chemicals produced by nematodes called ascarosides. This group of “worm chemicals” helps nematodes communicate with each other. The signaling molecules alert nematode-eating fungi of the worm’s proximity and, if conditions are right, will trigger the fungi to make traps. (1, 2)
One type of trap created by some nematophageous fungi are lassos (hyphal rings). These fungal cowboys wait until the unsuspecting prey swims through their lasso. Once the nematode moves through and triggers the hyphal ring, the lasso quickly fills with water and ensnares the worm. Another fungus captures nematodes by creating adhesive knobs and nets like a fisherman. When the nematode is caught in the sticky net, the fungus secretes a nematacide that kills its prey. Once their prey is imprisoned, both types of fungi will slowly digest their prize. (3)
Quid Pro Quo
Nematodes are categorized into groups based on their feeding habits; bacterial-feeders, fungal-feeders, and plant parasites. Therefore the bacterial- and fungal-feeders will be found with their preferred food in a high concentration of decomposing organic matter. (4) Fungi, bacteria, and nematodes are a micro-part of the global nitrogen cycle and the “nematodes contribute directly to nutrient mineralization through their feeding interactions.”(5) An example is when nematodes “graze” on N-containing bacteria and release the nitrogen back into the soil with their feces.
Nematodes Prefer Pores
A factor that can affect the health and growth of nematodes is the porosity of the soil; larger pores allow them to move freely while looking for food. Lack of porosity and other factors can adversely affect “all soil microbes,” including soil compaction, low water & gas levels, lack of organic matter, and extreme pH. For example, fungi thrive in slightly acidic soils and bacteria tend to do well in more neutral soils – extreme acidity or alkalinity (basic) will hamper both their growth.
When mixing VITAL Blend soil amendment into your soil, the end-results are reduced soil compaction and improved soil texture. Our organic blend of activated Biochar and plant-derived Humate will increase soil porosity and help hold moisture and oxygen in the soil. VITAL Blend will immediately improve soil health and the microbial populations will multiply naturally, including our fungal cowboys and fishermen!
(1) “Worm-Eating Fungi Eavesdrop on the Chemicals of Their Prey,” Yong, E. National Geographic – Not Exactly Rocket Science, Dec. 18, 2012.
(2) “Nematode-Trapping Fungi Eavesdrop on Nematode Pheromones,” Hsueh et al. Curr Biology, 23(1):83-6, Jan. 2013.
(3) “Nematode-Trapping Fungi,” Hauser, J. Carnivorous Plant Newsletter. Vol 14, 1985, pp 8-11.
(4) “Soil Nematodes,” Coleman, D.C. and Wall, D.H. Soil Microbiology, Ecology and Biochemistry, 2015, pp 111-149.
(5) “Soil Nematodes in Organic Farming Systems,” Ugarte, C. and Zaborski, E. eOrganic article from eXtension.org, April 8, 2014.