Fungal Networks

Fungi are perhaps the most overlooked members of an ecosystem. As well as acting as decomposers, thereby playing a crucial role in the global carbon cycle, fungi also form connections with plant root systems and allow the transfer of nutrients over far wider spatial scales than would be possible in their absence. They have great potential in areas of biotechnology such as biocontrol (i.e. use as a biological control agent), bioremediation (cleaning up polluted landscapes) and could possibly be used in agriculture to reduce the reliance on chemicals.

In collaboration with Fordyce Davidson & Geoff Gadd (Uni. of Dundee) and Karl Ritz (Uni. of Cranfield), a series of mathematical models have been constructed that simulate the development of mycelial networks in environments exhibiting nutritional and structural temporal heterogenities. These models make quantitative predictions on the growth and function of mycelial fungi and can aid in the biotechnological applications of fungi described above.

A three-dimensional mycelial network that has developed within a soil-like structure

Steven Hopkins, a research student supervised by Graeme Boswell and Ron Wiltshire, recently completed his PhD where he investigated lattice-free models of fungal growth by applying a velocity-jump approach to simulate the development of the mycelial network. The resultant networks more closely resemble actual fungal mycelia than any previous mathematical model and provide a quantitative relationship between the micro- and the macro-scale. Furthermore, the modellng predicts that the origin of cord formation (routes accounting for the majority of nutrient transport) in mycelial fungi is an initially stochastic but then self-reinforcing process. This work has been published in numerous peer-reviewed journals details of which are available under the Journal Publications section of this web portal.

More recent work by Graeme Boswell has focussed on modelling interactions between fungal colonies, principally understanding combat and competition between rival species since, in application, fungi do not grow in isolation and instead experience numerous interactions with other fungal communities. Typically in experimental settings, parwise combat between two fungi display exhibit either displacement (the continuous replacement of one fungi by another), deadlock (often arising because the fungi form barriers at their interaction fronts) or overgrowth (i.e. coexistence). The modelling has shown that through the simple decay of hyphae and hyphal tips between two rival fungi engaged in combat is sufficient to generate these behaviours. Furthermore, the creation of barriers is predicted to arise through a change in the nutrient translocation rate (consistent with experimental observations relating to the formation of sclerotia in fungi). But perhaps the most bizarre behaviour displayed by fungi is that they do not have a transitive heirarcy (e.g. if A displaces B, B displaces C then it does not follow that A displaces C). The modelling has shown that a small change in a parameter (the rate of tip degradation in combat or the rate of hyphal degradation) for a species-specific interaction is sufficient to generate this phenomina. This work has been published in 2012 in the Journal of Theoretical Biology.

For more information please contact Graeme Boswell.