In the words of Tyler DeWitt, “let me tell you a story”. Today’s story is about a fly, a carrion fly that eats the rotting carcasses of animals. This little fly can tell us about what it was feeding on, which could have been a rare or endangered species that we may not have known was present in that environment. As Ed Yong recently described it “An antelope falls in a forest and there’s no one around to hear it. But there are plenty of things that will eat it.” Researchers from Germany, Calvignac-Spencer and colleagues recently published a paper where they studied the DNA from blow flies that also revealed the DNA from its last meal.
The sites used for this study included Taï National Park in Côte d’Ivoire and Kirindy Forest, Madagascar. Calvignac-Spencer’s study began by investigating the feasibility of the idea by placing known meat samples in the field and then sampling the blow flies that fed on the carcass. The flies were captured using mosquito nets and bottles. The results indicated that by extracting DNA from the entire fly, DNA sequences from the known carcasses could also be derived. In addition, the authors conducted a blind test and sampled 115 blow flies without known exposure to wildlife carcasses from the two study areas and found that about 40% of the flies contained mammal DNA that could be identified to species. The results provided an insight into mammalian biodiversity and described 16 taxa from Taï and four from Kirindy. One of the species included Jentink’s duiker, a rare and endangered species. The results also indicated that if the authors sampled additional flies, they would have continued to find more animals.
This simple but exciting study has shown us the power of DNA and how advancing molecular techniques are providing us with new and innovative ways to survey mammalian biodiversity. How could a study such as this be conducted in Ireland? Perhaps we could use mosquitoes or blow flies captured in woodlands to estimate mammalian diversity? We have far fewer species than what you might find in biodiversity hotspots, but considering we know very little about many of our mammalian assemblages, approaches such as this, could bring new and exciting opportunities to us. Although, given the size of Irish woodlands and the proximity to nearby agricultural landscapes, I’m sure we’d find quite a few cows and sheep!
By the way, I’d like to thank Jacinta Mullins, aka The Singlelingual for introducing me to Tyler DeWitt’s great talk on TED, that helped inspire the blog entry.
Calvignac-Spencer, S., Merkel, K., Kutzner, N., Kühl, H., Boesch, C., Kappeler, P., Metzger, S., Schubert, G., & Leendertz, F. (2013). Carrion fly-derived DNA as a tool for comprehensive and cost-effective assessment of mammalian biodiversity Molecular Ecology, 22 (4), 915-924 DOI: 10.1111/mec.12183
Portlaw Woods, Co. Waterford
