Effects of fungivory by two specialist ciid beetles (Octotemnus glabriculus and Cis boleti) on the reproductive fitness of their host fungus, Coriolus versicolor

On the basis of the evidence that insect fungivory has the potential to aff ect fungal reproductive fitness, we investigated the effects of two special ist ciid beetles (Octotemnus glabriculus and Cis boleti) on the reproductiv e potential of their host fungus, Coriolus versicolor. We found, from field data, a negative correlation between the number of individuals of O. glabr iculus inhabiting C. versicolor fruit bodies and the percentage of the fung al spore-producing surface (hymenium) that was functional. By contrast, the number of C. boleti inhabiting C. versicolor fruit bodies did not correlat e with the percentage of functional hymenium. Experimentally, O. glabriculu s and C. boleti reduced the reproductive potential of C. versicolor by 58% and 30%, respectively, whereas the combined trophic activity of both beetle s caused a reduction of 64%. This latter effect was not significantly diffe rent from that caused by O. glabriculus alone. These findings disagree with previous assertions that insect fungivory on fruit bodies has only neutral effects on fungal fitness. We conclude that in the short-term, fungivory b y ciids significantly decreases the area of functional hymenium of C. versi color and is likely to reduce fungal reproductive fitness. Within this pers pective the evolution of certain fungal characteristics (i.e. chemical comp osition, consistency and phenology) can be interpreted as being driven by f ungivory.