Scientists recently discovered the remains of a 52-million-year old beetle trapped in a piece of amber in India. This beetle spent its life living near ants, inserting itself into their society, where it used their resources and ate their eggs.
Although the discovery of the beetle is fascinating enough, the find also tells us much about ants that lived millions of years ago.
"Although ants are an integral part of most terrestrial ecosystems today, at the time that this beetle was walking the Earth, ants were just beginning to take off, and these beetles were right there inside the ant colonies, deceiving them and exploiting them," says lead author Joseph Parker. "This tells us something not just about the beetles, but also about the ants -- their nests were big enough and resource-rich enough to be worthy of exploitation by these super-specialized insects."
Eventually, ant populations increased, and as that happened, so did the populations of these beetles.
There are over 300 varieties of these kind of beetles today, although scientists speculate that hundreds of species have not yet been discovered. What makes them so unique is that they're sneaky, so much so that they can infiltrate ant nests, which have a built-in pheromone security system that should set off an alarm. Generally speaking, intruders are dealt a harsh punishment, which includes dismemberment and death.
These beetles, however, waltz on in to the ant nest and are treated as ants themselves, even being fed regurgitated liquids by worker ants. Meanwhile, they suck up the ants' resources and feed on their eggs and children. But the ants never figure out that there are traitors in their midst.
Living in the ant colony has other benefits for the beetles, as well. The area of an ant nest has a consistent climate and is secure from invaders, except for other similar beetles, of course.
Interestingly enough, although we know of hundreds of species of these beetles, scientists haven't seen much of them. That makes this fossil a unique and valuable find, especially since the beetle's body is a little different from its modern counterparts. The beetle in amber has several distinct abdominal sections. In comparison, modern species of beetles have a single abdominal segment.
"Protoclaviger is a truly transitional fossil," says Parker. "It marks a big step along the pathway that led to the highly modified social parasites we see today, and it helps us figure out the sequence of events that led to this sophisticated morphology."
