Interspecific competitive ability of homokaryotic and heterokaryotic wood decay basidiomycetes

The role of the homokaryotic life stage in the dynamics of fungal communities is relatively unknown. However, homokaryons are thought to be only a temporary stage and are therefore not generally used in ecological experiments with fungi. In this study, the relative competitive ability and growth rates of homokaryons and heterokaryons of wood decay fungi were tested to assess the potential role of homokaryons in community dynamics. A homokaryon and a heterokaryon of each of four species (Aleurodiscus lividocoeruleus, Peniophora sp. 1, Peniophora sp. 2 and Pereniporia medulla‐panis) were assessed for their competitive abilities on an agar medium. The relationship between nuclear status and competitive ability varied between species. The homokaryon of Peniophora sp. 2 was competitively superior to its heterokaryon, whereas the homokaryon of Peniophora sp. 1 was inferior to its heterokaryon. A hierarchy of competitive abilities of each isolate revealed that Pereniporia medulla‐panis homokaryon = P. medulla‐panis heterokaryon > Peniophora sp. 1 heterokaryon > Peniophora sp. 2 homokaryon > Peniophora sp. 2 heterokaryon > A. lividocoeruleus heterokaryon = A. lividocoeruleus homokaryon. This experiment indicates that homokaryons as well as heterokaryons have the potential to influence community structure through competitive effects.