The wings and head of this darner (Aeshnidae) were all that remained from a recent bird feast (presumably) at 10-Acre Pond today. I found them under the power lines. I saw irony in this discovery, as several of the odonates I collected there today ended up with missing heads and wings. But these remains also got me thinking about insect ichnospecimens. Is there a huge collection of bird/bat/shrew/whatever turds, or fish guts, avian pellets, or even insect frass somewhere that would allow us to explore changes in diet over time? There must be. If not we’ll build it here at the Frost. We already have a small “insects from owl pellets” collection!
(Incidentally, my interest in insect remains—in bat guts—is what drew me into the world of systematic entomology.)
UPDATE: We’ve determined this specimen as the remains of a Spatterdock Darner (Rhionaschna mutata).
One of my professors at LSU once suggested gut content as a means to establish predator prey relationships in the insect world. He cited the sequencing of of such materials in deep sea worms to determine predator-prey relationships. I think that building a “poo collection” is not just a good idea but a nessecity for a better understanding of trophic interactions in the world about us.
The real question I have is how exactly do you preserve fecal remains properly? Does everything need to be in alcohol to preserve as much potential genetic material as possible? Is dried the way to go for morphology? Is it a little of both? Is there some other method?
All great questions! I wonder what if anything has been sequenced from various ancient coprolites (Google Scholar suggests quite a bit has been done on DNA from poop). Maybe one can get reasonable DNA from dried/old material (I suspect they can). We could always freeze it, as well. I did find a paper about odonate fecal pellets, and how one can determine their diet by looking at the morphology of the chunks (mosquito scales, for example, or bits of metallic cuticle), even though the prey go through an extensive maceration. I can’t find that paper right now for the life of me!