EPOW - Ecology Picture of the Week

Attack !

Unidentified Ants and Worm
Modi River Valley, Nepal

Explanation:  Attack !

As I was trekking through the village of Pattekhet in the Modi River Valley of the Himalayan mountains of Nepal, I noticed a very odd scene that I had never witnessed before.  A mass of ground-nesting ants were attacking a harmless earthworm.

Earthworms provide vital ecosystem functions by consuming detritus -- dead and decaying organic material -- converting it into productive soil.  They are of no threat to ants.  Why, then, were these ants vigorously and mercilessly attacking this worm?

Some ants might occasionally consume a dead earthworm, but this worm was still alive, wriggling and fighting to get clear of the attack.  However, some ants are more aggressive, such as army ants, fire ants, pavement ants, and even carpenter ants such as those chewing the wood of your (my) back deck at home.  

Apparently, it turns out, ants attacking earthworms is not an unheard-of phenomenon.  The ants may be feeding on the worm.  I also hypothesize that perhaps the ants and worm were occupying the same ground burrow and the ants wanted to dispose of their unwanted roommate, but this hypothesis needs testing (however, it is not recommended to emulate the ants on your own unwanted roommate...).