The Largest “Poopathlon” in Honduras: First List of Dung Beetles

Honduras has little documented published records of the biodiversity of its ecosystems. Amphibians, reptiles, and birds are among the most studied biological groups, with information available on their biology and species distribution. Even for fish and mammals, there are books or articles, but they are not up to date, and recent updates are scattered across countless platforms.

Insects constitute a complex group to study when trying to determine the species present in a region, as observation and collection methods are usually longer and more tedious, and biodiversity-wise they are simply exponentially more diverse. Perhaps the most comprehensive work on insects is the guide to butterflies of Honduras by Gallardo and Díaz (2023). Therefore, today I introduce another taxonomic group whose study is filling gaps in the entomofauna (the entire set of insects in a given area) of our country: dung beetles. This group is being studied by Honduran scientist Dr. Daniel Rivera, one of the authors of the article I will be summarizing.

To begin, let me explain what dung beetles are. Beetles are the most diverse group of insects, found in almost all types of ecosystems, and their feeding habits vary. Within this group we find dung beetles, whose peculiarity is that their larvae feed on excrement (in biological terms, they are coprophagous species)—yes, you read that correctly.

 Figure 1. Beetle morphology. Photo by Mauricio Michel.

How is this possible? Adult beetles are responsible for obtaining dung (mainly from mammals), which will serve as food for their offspring. Some beetles simply use the same place where the dung is found as their home. Others dig tunnels beneath the dung. Meanwhile, some beetles form balls of dung and roll them to their refuge. Once the site is ready, the female lays her eggs inside that ball. There, the larva will have everything it needs to grow, as dung is a nutrient-rich resource.

Figure 2. Diagram of different ways that beetles transport their poop balls. 1 burial under excrement pile; 2 ball formation under excrement; 3 ball rolling to nest.

This behavior is not only important for the beetles. These dung balls also help recycle nutrients, improve soil quality, and enhance water retention. Additionally, if the dung contains seeds, beetles also act as seed dispersers, promoting natural regeneration. They also control pests, reduce greenhouse gas emissions, and contribute to maintaining ecological balance.

How was the “poopathlon” conducted?

This recent study on the country’s dung beetle fauna revealed a much greater diversity than previously known. To obtain the 98 species of dung beetles, three methods were used:

• Pitfall traps placed in seven departments of Honduras between 2023 and 2024.

• Review of the entomological collection at Zamorano University.

• Bibliographic review of reported collections of these species.

  
  

The sampled sites included several national parks, wildlife refuges, and forest patches across Honduras (Figure 3).

Figure 3. Departaments where the 'poopathlón' was done. 

Pitfall traps

This is perhaps the most visually interesting part—though not the most pleasant in terms of smell. Pitfall traps consist of burying a 1000 ml container in the ground, filled with 250 ml of a mixture (water, soap, and salt) used to trap and preserve beetles. This is accompanied by a small cup containing dung—human or pig dung—used as bait to attract adult beetles. A plastic plate is placed on top to protect the trap from sun and rain.

The trap is left for 48 hours, then checked. If beetles are found, they are collected and preserved in alcohol for later identification in the laboratory.

Figure 4. Staging of pitfall traps: first picture shows the container with the mixed solution and the bait, then the trap is covered with a plate to protect from rain, heat and other animals. The third picture shows the beetles trapped in the mixed solution.

Here's where that word on the title comes from, the 'poopathlon' (cacatlón in Spanish) refers to how around 276-285 pitfall traps were displayed in the field, needing between 6,900-7,125 grams of human poop. Clearly this didn't come from a single person, but was a proud team effort of the research team and some civilians who were around at the time and wished to support science (guides, local people, friends).

Want to know something curious? Not every poop is of "good quality"; if it's too hard or too liquid, that can be a methodological disaster. There are solutions, but they require further poop handling. Therefore, voluntaries need to eat healthily and not suffer from constipation. There are some who need peace and tranquility to do their business, but others are encouraged by stress. There's a bit of everything in the world of scarab science.

This was my first time visiting Brus Laguna in La Mosquitia in the east of Honduras. It was also my first time sampling these type of beetles, so I had to observed with detail how the experts did everything. Let it also be said that this was an international research trip, with biologists from Colombia, Brazil, Mexico and of course, Honduras. I watched the methodology and didn't find it hard; the hardest was obtaining the poop and manipulating it. One false movement and you can get it on you, or on someone else, something nobody wanted to happen. Your gloves can also rip once you hang around branches, the ground, if the glove is too tight or your nails are long. Or simply, getting distracted for a few seconds could cause complete chaos.

As good observer as I think I am, I saw that the technique on how the poop gets cupped could be improved (Figura 5), since initially a plastic disposable spoon was used. I remembered the times that I have baked pastries, and thought that we could use something akin to a piping bag, that instead of cake, would have poop. Turns out I was right! This technique made everything more practical, a thousand times better. That's why I always say that housework can transform to fieldwork in the least expected moments.

Figure 5. Very carefully placing the poop bait on the pitfall trap.

I have to come clean though, during this first sampling at Brus Laguna, I contributed no fecal material. Naturally you have to grow out of the shame, since at first it is nearly inconceivable to have to do it. But with more experience, I can now say that once you do it, shame goes away and you suddenly feel more at ease to take part of all the poop jokes that come out. Now imagine gatering several people studying this group and sharing this type of anecdotes. Uncomfortable? Maybe. Fun? Definetely. At the end of the day, good laughs are never bad.

From 42 to 98: a positive increase in scarab beetle knowledge

It's not like we didn't know about these species before, however before 2023, only 42 species were officially recorded for Honduras [5]. In 2024, this number increased by about 133.33%, which evidences how much knowledge was and still is waiting for discovery. Perhaps what's most valuable about this species update is that the project was spearheaded by a Honduran, with the objective of filling scarab beetle diversity gaps in the country. Another interesting aspect is that this number will keep growing, since the study missed many other Honduran regions.

Ninety-eight species of scarab beetles were recorded; two in the family Bolboceratidae, one in the family Geotrupidae and 95 in Scarabaeinae. Of these 98 species, four are endemic to our country: Ateuchus perpusillus, Copris nubilosus, Onthophagus breviconus and Phanaeus lempira. An endemic species is one that is naturally restricted to a particular region, in this case Honduras. In other words, it can't be found anywhere else.

If you want to see a summarized list of the species found, you can check out the following document in Spanish:

Lista_Escarabajos_Estercoloros.pdf

Download PDF • 154KB

Figure 6. Some species collected in pitfall traps. A Haplogeotrupes guatemalensis tridentatus; B Canthon sallei; C Phanaeus endymion; D Sulcophanaeus chryseicollis.  Photos by Mauricio Michel.

One of the most important discoveries was the description of a new species; not a new record, but a worldwide new species. Phanaeus lempira Kohlmann, Solís & Rivera (Figure 7) was found at Parque Nacional Montaña de Celaque, Gracias, Lempira. This species name honors our National Hero, symbol of liberty and cultural resistance, who fought against the Spanish invasion and conquest: Lempira [2].

 Figure 7. Newly described species, Phanaeus lempira. Male individual in the first picture, followed by a female. Photos by Mauricio Michel.

You may be wondering, what is the importance of knowing which scarab beetles exist in Honduras? Firstly, it is fundamental to know a country's biodiversity. This knowledge is reflected on new records and the description of new species. This same group is still working in hte description of four additional new species, which evidences that there is still a lot to discover.

Secondly, the abundance and diversity of these beetles are closely related to good ecosystem functioning [6,7]. In a productive forest, the presence of mammals implies availability of feces, a key resource for these insects. And if there are big mammals, this is a sign of a healthy forest. Spoiler alert: in the near future, one of the authors of this study might publish a paper related to the interaction of a mammal with these beetles in our country.

Thirdly, going out to the field to do these kind of samplings not only fortifies our technical-scientific knowldege, but it also helps connect to nature and your colleagues. Besides, this type of work always leaves the ecologists-entomologists and especially the “caqueros” happy.

Next time you're on the field and find poop (cow poop hopefully), lift it up and pay attention and see whether you can spot these beetles that just might be roaming around for you. Of course, please use gloves or a nearby branch, don't use your hands because you should keep biosafety in mind. This will make you aware that there are organisms that benefit from other organisms' poop. Had to believe right? Well, nature never ceases to amaze.

The authors of this study are looking forward to exploring new areas of Honduras and discovering new records and even new species. However, these efforts are limited by the lack of resources for field work, which imply transportation and special supplies. Supporting this project represents a key opportunity to contribute to the knowledge and conservation of our biodiversity. If you are part of an NGO or institution that is interested in supporting this project, please contact:

joseduarte@unah.edu.hn.

Figure 8. Souvenir from Brus Laguna with the field team. Left to right: Renato Salomão (study co-author), José Daniel Rivera (study co-author), Marcos Odair Rodríguez Wood from Brus Laguna, Mayab Xel-Ha Martínez Castaneira, Maria José Bú, Catalina Maria Suarez Tovar, Manuel Edday Farfán-Beltrán and Valentina Sandoval Granillo. Also Eudoro Portillo Curly from Brus Laguna.

Congratulations to my Honduran colleagues for being part of this great project: MSc. Dr. Jose Daniel Rivera and Marcela I. Matamoros. It is a pleasure to know you and work with you. ❤️Thanks to Laboratorio de Hidrobiología UNAH for supporting this project and letting me take part of this trip to Brus Laguna.

Paper link: https://doi.org/10.3897/zookeys.1255.150586

By: Maria José Bú, Biologist

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References

1. Gallardo, R. J., & Díaz, O. (2023). Guide to the butterflies of Honduras. Robert Gallardo. 367 p.

2. Rivera-Duarte JD, Salomão RP, Solís Ángel, Michel M, Matamoros MI, Kohlmann B (2025) The Bolboceratidae, Geotrupidae (Coleoptera, Scarabaeoidea), and Scarabaeinae (Coleoptera, Scarabaeoidea, Scarabaeidae) fauna of Honduras: Taxonomy and distribution. ZooKeys 1255: 127–206. https://doi.org/10.3897/ zookeys.1255.150586

3. Kohlmann, B. 2022. Escarabajos estercoleros (Aphodiidae, Geotrupidae y Scarabaeidae). En: La biodiversidad en Oaxaca. Estudio de Estado. Vol. II. CONABIO, México, pp. 61-72.

4. INECOL y FMCN (2022), Guía de escarabajos estercoleros de Chiapas y el centro-sur de Veracruz, FMCN-Agencia Francesa de Desarrollo, México

5. Cupello M, Silva FAB and Vaz-de-Mello FZ (2023) The Taxonomic Revolution of New World dung beetles (Coleoptera: Scarabaeidae: Scarabaeinae). Front. Ecol. Evol. 11:1168754. doi: 10.3389/fevo.2023.1168754

6. Harvey, Celia & Gonzalez, Jorge & Somarriba, Eduardo. (2006). Dung Beetle and Terrestrial Mammal Diversity in Forests, Indigenous Agroforestry Systems and Plantain Monocultures in Talamanca, Costa Rica. Biodiversity and Conservation. 15. 555-585. 10.1007/s10531-005-2088-2.

7. Escobar, F. (2000). Diversidad y distribución de los escarabajos del estiércol (Coleoptera: Scarabaeidae: Scarabaeinae) de Colombia. Sociedad Entomológica Aragonesa, 1, 197–210.