[Believe it or not, this post has sat in draft form in the system since I started it in April 2013 – it never seemed to fit in among other posts that well. So it gets to appear now as a Darwin Day post while photography has hit the winter slump. There’s still a chance something else might appear, but no promises.]
A few weeks back [a ha ha ha!] when I was at the river I obtained some images of trees where beavers had stripped some of the bark, and on returning and unloading the memory card, I noticed that the oozing tree resin had snared an ant. Returning later (but on a day earlier than this,) I specifically tried to find examples of this again. There is a possibility that what you’re seeing may reappear in a few million years as a fossil. But, not a very good possibility.
Anyone familiar with types of fossils (or that simply remembers their Jurassic Park) knows that amber is tree resin that underwent the right conditions to become preserved, turning into a gemstone of sorts over a very long period of time. And a significant amount of what we know about prehistoric arthropods comes from finding them preserved in amber, having perished exactly as you see here. It is perhaps the most accurate and complete information to be gathered from fossils, since the process can preserve even microscopic details – but, alas, no DNA to engineer ancient sauropods, since DNA simply cannot survive for that long.
Yet, like all fossilization processes, it’s exceedingly rare. The resin would have to encapsulate the insect completely, then detach and become buried in sediment almost immediately, since it breaks down due to environment and bacteria just like everything else. The sediment, naturally, cannot be washed away anytime in the next several thousand years, meaning it has to exist in an area that undergoes only accumulation and no turbulence, flooding, or major land upheavals. Only then can the transformation process go on long enough to turn the resin into a durable ‘crystal.’
This is why the fossil record is sporadic – those are very distinctive conditions, not found many places at all. Even enough oxygen trapped in the mud can allow bacterial decay to take place and wipe out any organism’s remains before the pressure of accumulation can do its work. Knowing the conditions of the riverbank where these images were taken, I can say that the chances of these insects being preserved are infinitesimally small. The current is highly variable and the sediment very limited, leaving little opportunity to even start to bury any of this resin when it falls from the tree, nor to carry it further downstream where conditions are more conducive. Moreover, this entire area (in fact, all of North Carolina and really, the entire east coast) is too geologically active to feature many areas that will remain stable – the Blue Ridge/Appalachian mountain range is eroding away, dispersing silicate-based rock towards the coast where it eventually grinds into sand. The mountain range itself was formed from colliding with the north African continental plate, and everything east of the range (which includes the area I type this from) had been seabottom until the mountains wore down under millions of years of rain onslaught and extended the coast eastward. This means there are no fossils to be found in this area unless one digs very deep – and that any potential surface remains are very likely to be destroyed under this slow but constant landslide to the sea.
So the victims here are unlikely to be preserved for posterity; in fact, one at lower left has already been removed by something else, perhaps an opportunistic scavenger, leaving the legs and wings behind (not a fan of dark meat I guess.) Had I found this on the edge of the Mississippi River Delta, then maybe there would have been a greater chance of being buried under ongoing accumulation and becoming a tiny little record of this era’s life. Or maybe I could collect one and throw it in the septic tank…
By the way, a small distinction that I learned myself when looking up the conditions for creating amber: this is resin, not sap, which is thinner and accomplishes different things within a tree. Sap carries the nutrients throughout a tree, while resin is simply a property of the wood, possibly contributing to the moisture barrier that prevents the tree from dying when subjected to damage such as this. Quite a few trees by the river exhibit signs of beaver activity, some from years ago; they recover. Life, uh, finds a way.