Evidence for emergent behaviour in the community-scale dynamics of a fungal microcosm

Abstract

A stochastic cellular automaton for modelling the dynamics of a two-species fungal microcosm is presented. The state of each cell in the automaton depends on the state of a prede¢ned neighbourhood via a set of conditional probabilities derived from experiments conducted on pairwise combinations of species. The model is tested by detailed comparison with larger-scale experimental microcosms. By employing di¡erent hypotheses which relate the pairwise data to the conditional probabilities in the model, the nature of the local and non-local interactions in the community is explored. The hypothesis that the large-scale dynamics are a consequence of independent interactions between species in a local neighbourhood can be excluded at the 5% signi¢cance level. The form of the interdependencies is determined and it is shown that the outcome of the interactions at the local neighbourhood-scale depends on the community-scale patterning of individuals. The dynamics of the microcosm are therefore an emergent property of the system of interacting mycelia that cannot be deduced from a study of the components in isolation.

Modelling interactions in fungi

“…Likewise, the model presented in Bown et al (1999) is not able to predict the interaction outcomes detailed here.…”

“…Such a modelling framework permits an investigative approach (Marks & Lechowicz 2006), where we are able to explore and interpret the underlying mechanisms that lead to the colony formations. The only other modelling frameworks that we are aware of, which consider fungal interactions, are Davidson et al (1996) and Bown et al (1999). Davidson et al (1996) consider fungal interactions in terms of a collision between two initially distinct activator concentrations (an initial activator concentration corresponds to a fungal inoculum).…”

A New Paradigm for SpeckNets: Inspiration from Fungal Colonies

“…This communication can be enhanced by some hyphae fusing and becoming anastomosised (see centre of figure 1(b)). Thus the colony can be considered an integrated unit and is more than the sum of its individual hyphae [3]. Different events occurring within the colony cannot therefore be totally independent and the local environments occurring within the mycelial boundary cannot all be treated as entirely separate domains.…”

Biomass recycling and the origin of phenotype in fungal mycelia

“…A mycelium, or fungal colony, has no characteristic scale above that of an individual hypha (the basic unit of the mycelium) and can potentially persist indefinitely, reproducing when environmental circumstances are favourable. The connected nature of the mycelial network means that local behaviour can, and is, affected by conditions in remote parts of the colony via mechanisms including translocation (White et al 1998;Bown et al 1999;Olsson 1999). Therefore, the behaviour of the colony is dependent on the interaction between genotype and a complex spatial convolution of environmental conditions across the whole mycelium.…”

“…Although phenomenological, the model illustrates the important point that relatively few processes can be orchestrated by different contexts to produce wide-ranging phenotypes, and this capacity must be embodied in any general representation. Bown et al (1999) chose a multi-scaled approach to examine the relative contribution of local and non-local effects on the dynamics of a two-species fungal microcosm. This model represents implicitly the physiological processes that are important in the outcome of individual fungal interactions.…”