Mosses usually keep a low profile, quietly covering rocks and forest floors. But the Splachnaceae family takes a bolder approach—they grow on dung and carcasses and trick flies into spreading their spores. Instead of relying on wind, like most bryophytes, they use smell and color to lure those flies (Marino, Raguso, & Goffinet, 2009).
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| Splachnum sphaericum, ©Johannes Merz |
"Sompasammalet" Exhibition
These unusual mosses recently took center stage at the Sompasammalet exhibition at the University of Turku. The exhibition is part of a citizen science effort to map the distribution of sompasammalet (Splachnaceae), especially Splachnum melanocaulon, in Finland. Four genera of Splachnaceae occur in Finland; Splachnum, Aplodon, Tayloria, Tetraplodon (FinBIF 2025). Splachnaceae are an ideal group for public engagement because they overtop what people expect from mosses. With their vibrant colors, unusually large sporophytes, and bizarre habitats—growing on dung and carcasses—they’re eye-catching, memorable, and full of surprise. Their clever fly-based dispersal strategy adds an extra layer of intrigue. Because they’re relatively easy to recognize in the field, they offer a fun and accessible entry point into the world of bryophytes. Public participation not only improves knowledge of their distribution but also sparks broader appreciation for moss diversity and ecological roles.
More information about the project in Finland: Erikoisia sammalia esittelevä Korpisuon kaunokaiset -näyttely avautuu Turun kasvitieteellisellä puutarhalla 2.4. | Turun yliopisto
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| Splachnum luteum and S. rubrum herbarium samples from Turku Herbarium, ©Johannes Merz |
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| Tayloria gunnii, ©Jenny Schorta |
The Chemical Trickery of Splachnaceae
Splachnaceae don’t just look striking—they also produce a fascinating array of chemicals to manipulate their insect dispersers. Their spore capsules release volatile organic compounds (VOCs) that mimic the scents of dung, carrion, and urine to attract flies (Marino, Raguso, & Goffinet, 2009; Rosenstiel, Eitinger, & Rensing, 2014, Kjellberg, 1971). Different species produce distinct blends of these compounds. When the flies land, spores stick to their bodies, hitching a ride to fresh dung perfect for new moss growth.
For example, Splachnum ampullaceum emits a complex blend including phenol, p-cresol, indole, and dimethyl disulfide—compounds commonly associated with feces and carrion, Splachnum sphaericum produces a similar profile but with lower intensity, reflecting potential differences in habitat preference and disperser communities. Other emitted compounds, including phenols and cresols, are associated with herbivore dung, further enhancing the deceptive mimicry (Marino, Raguso, & Goffinet, 2009; Rosenstiel et al., 2014). Some species even emit floral-like scents, adding another layer of complexity to their chemical signaling (Marino, Raguso, & Goffinet, 2009).
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| Tayloria octoblepharum growing on a skull, © Em Lamond |
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Flies like flashy colors
It’s not just the smell that draws in flies. Many Splachnaceae species, like Splachnum rubrum and Tetraplodon mnioides, have striking red, purple, or yellow sporophytes. These bright colors catch the attention of flies, making the moss even more irresistible (Marino et al., 2009; Imura, 1994).
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| Tetraplodon mnioides, ©Johannes Merz |
Evolutionary Ingenuity
When flies land on a sporophyte, sticky spores attach to their bodies, hitching a ride to another patch of dung or carcass—ideal habitat for the moss's next generation. This insect-based dispersal strategy, called entomophily, evolved independently multiple times within the family, suggesting it offers a strong evolutionary advantage in the nutrient-rich, scattered habitats that animal droppings are (Goffinet, Shaw, & Cox, 2004). Field observations even suggest that some Splachnaceae species may attract specific fly species, hinting at a deeper relationship that likely developed over evolutionary time (Kjellberg, 1971). These remarkable mosses don’t just grow in unusual places—they've evolved a highly specialized partnership with insects, making them the only mosses that are entomophilic.
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| Aplodon wormskioldii, ©Danilova Valeria |
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| Habitat of Tetraplodon mnioides, subarctic tundra in Norway, ©Johannes Merz |
References
Imura, S. (1994). Spore dispersal by flies in Splachnum ampullaceum Hedw. Hikobia, 11(4), 505-510.
Kjellberg, B. (1971). Dispersal and establishment of species from the genus Splachnum. Lindbergia, 1(1), 43-58.
Marino, P., Raguso, R. A., & Goffinet, B. (2009). The ecology and evolution of fly-dispersed dung mosses (Family Splachnaceae): Manipulating insect behaviour through odour and visual cues. The Bryologist, 112(3), 455-466. https://doi.org/10.1639/0007-2745-112.3.455
Schuster, R. M. (1966). The Hepaticae and Anthocerotae of North America. Volume I. Columbia University Press.
Watson, E. V. (1974). British Mosses and Liverworts. Cambridge University Press.
Rosenstiel, T. N., Eitinger, A. C., & Rensing, K. H. (2014). Structural changes in plastids of developing Splachnum ampullaceum sporophytes and relationship to odour production. The Bryologist, 117(3), 209–219. https://www.researchgate.net/publication/265556598
Finnish Biodiversity Information Facility (FinBIF). (2025). Splachnaceae. Retrieved April 4, 2025, from https://laji.fi/taxon/MX.212960
Goffinet, B., Shaw, A. J., & Cox, C. J. (2004). Phylogenetic inferences and nucleotide substitution models: A case study with the mosses. Molecular Phylogenetics and Evolution, 31(2), 686–703. https://doi.org/10.1016/j.ympev.2003.08.024