Overview of the global research on dung-inhabiting fungi: trends, gaps, and biases

Dung-inhabiting fungi are specialized to grow on dung. The coprophilous habit required these fungi to have physiological adaptations to survive on dung, so they developed a variety of metabolites to exploit the resource and tolerate intra and interspecific competition. These fungi are important cyclers of matter/energy in terrestrial ecosystems, but they are poorly studied. We analyzed the global scientific production involving these fungi, using a systematic review and scientometric methods. We found 661 publications, with temporal distribution showing a marked increase in publications from the 1970s onwards with the widespread of the moist chamber technique facilitating the studying these fungi. Twelve journals account 37% of publications, with Fungal Biology with most publications (33). A total of 15 countries from a total of 54 concentrate more than half (65%) of the publications, with the USA (79), United Kingdom (66), Brazil (36), and India (33) having the greatest production ( 30), but there are lots of unexplored geographic areas regarding this biodiversity, to which attention should be given. Most studies are divided between paleobiological or taxonomic/ecological approach, with the latter group being trend among studies produced in developing countries. Fifty-eight species were involved in studies on secondary metabolites or another biological processes, with Podospora anserina (syn. Triangularia anserina and Thermochaetoides thermophila (syn. Chaetomium thermophilum) being the most studied. We hope our data reinforce the need for new research/funding aimed this fungal group with the purpose of learning its potential and guaranteeing conservation and knowledge of their biodiversity through the valuation of the goods and services they can generate.