We often think of ants as paragons of hard work, but a surprising number of species get by through mooching off the labor of others. Trachymyrmex fungus growers, the larger spiny ants pictured above, do things the old-fashioned way. They dig their own nests, send workers out to gather food, and meticulously cultivate the fungus garden that serves as the primary food source for the colony.
Then, along comes the slim, sneaky Megalomyrmex symmetochus. These little parasites hollow out a cozy little nest within the Trachymyrmex garden and spend their time leisurely consuming the brood of their oblivious hosts. An easy life, for an ant.
photo details: Canon MP-E 65mm 1-5x macro lens on a Canon 20D
f/13, 1/250 sec, ISO 100
flash diffused through tracing paper
flash diffused through tracing paper
Myrmecos Blog 
why the Trachymyrmex do nothing ?
That’s a good question. I suspect that they might have defenses against a young parasite queen first trying to establish herself, but the researcher who studies them, Rachelle Adams, probably has a much better answer!