Mycophagy: A Global Review of Interactions between Invertebrates and Fungi

How cryptic animal vectors of fungi can influence forest health in a changing climate and how to anticipate them

Fungal spores are usually dispersed by wind, water, and animal vectors. Climate change is accelerating the spread of pathogens to new regions. While well-studied vectors like bark beetles and moths contribute to pathogen transmission, other, less-recognized animal species play a crucial role at different scales. Small-scale dispersers, such as mites, rodents, squirrels, and woodpeckers, facilitate fungal spread within trees or entire forest regions. On a larger scale, birds contribute significantly to long-distance fungal dispersal, potentially aiding the establishment of invasive species across continents. These vectors remain underexplored and are often overlooked in fungal disease studies and are therefore called cryptic vectors. Understanding the full range of dispersal mechanisms is critical as climate change drive shifts in species distributions and increases vector activity. Expanding monitoring and detection tools to include these hidden carriers will improve our ability to track the distribution of fungal pathogens. Integrating targeted research, innovative technologies, and collaborative efforts across disciplines and borders is essential for enhancing disease management and mitigating fungal disease's ecological and economic impacts. KEY POINTS: • Cryptic animal vectors play a critical role in fungal spore dispersal across forests and continents. • Climate change accelerates fungal pathogen spread by altering species distributions, increasing vector activity, and facilitating long-distance dispersal. • Innovative monitoring tools, like eDNA sampling and predictive modelling, are essential to uncover cryptic vector contributions and mitigate fungal disease impacts.

Toward harnessing biodiversity-ecosystem function relationships in fungi

Fungi are crucial for terrestrial ecosystems, yet the role of fungal diversity in ecosystem functions remains unclear. We synthesize fungal biodiversity and ecosystem function (BEF) relationships, focusing on plant biomass production, carbon storage, decomposition, and pathogen or parasite resistance. The observed BEF relationships for these ecosystem functions vary in strength and direction, complicating generalizations. Strong positive relationships are generally observed when multiple ecosystem functions are addressed simultaneously. Often, fungal community composition outperforms species richness in predicting ecosystem functions. For more comprehensive fungal BEF research, we recommend studying natural communities, considering the simultaneous functions of a broader array of fungal guilds across spatiotemporal scales, and integrating community assembly concepts into BEF research. For this, we propose a conceptual framework and testable hypotheses.

Identification of Dipteran species inhabiting Tuber aestivum (the summer truffle) ascomata

Tuber spp. (Ascomycota) forms hypogeous fruiting bodies (truffles) that host many microbial species as well as invertebrates which feed on them. Despite the larvae and adults of Diptera and Coleoptera are commonly found to inhabit truffles, molecular investigations assessing their occurrence are still few and the number of species is probably underestimated. In this study, 52 larvae and adults of Diptera from 23 T. aestivum ascomata collected in two provinces of northern and central Italy were molecularly characterized. The sequences fell into four Diptera families, and four taxa were identified as Cheilosia soror, Phaonia cf. trimaculata, Drosophila subobscura, and Suillia gigantea. Morphology of adults belonging to these species confirmed their identity. Additional three taxa belonging to the Helomyzidae remained unclassified. The study highlighted the coexistence of different Diptera species in the same ascoma, suggesting potential lack of competitive exclusion. Geographical distribution analysis reveals non-site specificity for most species. This research contributes insights into the diversity of Dipteran species and their interactions with truffles and lays the groundwork for their monitoring, at a time where truffle resources are threatened by anthropic and environmental factors.

Molecular phylogeny and morphology reveal two new entomopathogenic species of Ophiocordyceps (Ophiocordycipitaceae, Hypocreales) parasitic on termites from China

Two new termite-pathogenic species, Ophiocordycepsglobiperitheciata and O.longistipes, are described from Yunnan Province, China. Six-locus (ITS, nrSSU, nrLSU, tef-1α, rpb1 and rpb2) phylogenetic analyses in combination with morphological observations were employed to characterize these two species. Phylogenetically, O.globiperitheciata is most closely related to Hirsutellacryptosclerotium and O.communis, whereas O.longistipes shares a sister relationship with O.fusiformis. However, O.globiperitheciata differs from H.cryptosclerotium by parasitizing Blattodea and producing clavate, unbifurcated stromata. Ophiocordycepsglobiperitheciata is distinguished from O.communis by multiple stromata, shorter asci and ascospores. Ophiocordycepslongistipes differs from O.fusiformis in producing larger stromata, perithecia, asci and ascospores, as well as smaller citriform or oval conidia. Morphological descriptions of the two new species and a dichotomous key to the 19 termite-pathogenic Ophiocordyceps species are presented.

Cladosporium-Insect Relationships

The range of interactions between Cladosporium, a ubiquitous fungal genus, and insects, a class including about 60% of the animal species, is extremely diverse. The broad case history of antagonism and mutualism connecting Cladosporium and insects is reviewed in this paper based on the examination of the available literature. Certain strains establish direct interactions with pests or beneficial insects or indirectly influence them through their endophytic development in plants. Entomopathogenicity is often connected to the production of toxic secondary metabolites, although there is a case where these compounds have been reported to favor pollinator attraction, suggesting an important role in angiosperm reproduction. Other relationships include mycophagy, which, on the other hand, may reflect an ecological advantage for these extremely adaptable fungi using insects as carriers for spreading in the environment. Several Cladosporium species colonize insect structures, such as galleries of ambrosia beetles, leaf rolls of attelabid weevils and galls formed by cecidomyid midges, playing a still uncertain symbiotic role. Finally, the occurrence of Cladosporium in the gut of several insect species has intriguing implications for pest management, also considering that some strains have proven to be able to degrade insecticides. These interactions especially deserve further investigation to understand the impact of these fungi on pest control measures and strategies to preserve beneficial insects.