This week is Army Ant Week, and while Alex Wild’s stunning photographs of this diverse and charismatic group reign supreme, some of the cooler bug bloggers are nevertheless getting into the spirit of things with army ant posts of their own. I have no such photos, but I’m hoping I can sneak onto the bandwagon with these images of leafcutting ants that I photographed last month in Campinas, Brazil.
These were among the first insects I saw during the trip once I got a bit of free time to walk the hotel grounds. Watching them crawl along the lower edge of the hotel wall was a welcome sight, as nothing says “tropics” to me more than columns of these ants carrying their bits of leaves back to the nest for use in their hidden fungus farms. While taxonomically they may be unrelated to army ants, their precise single file marches in dutiful service to the colony are as military as it gets. Army ants may have the jaws, but leaf-cutters have spines – they don’t just carry weapons, they are the weapons!
The thing I like most about leaf-cutter ants is that they are one of the few ant groups that I feel confident enough to hazard an attempt at identification. Several genera comprise the group, and most people who are at all familiar with them think of the genus Atta first. However, I recalled reading something on Alex’s blog about spines as a diagnostic character for attine ant genera – sure enough, in this post Alex explains how species in the genus Atta have two pairs of spines on the promesonotum, while those in the genus Acromyrmex bear three pairs. On this basis, I’ll go out on a limb and declare the individuals in these photos as Acromyrmex sp. (of course, which species is another story – James? Alex?). If I’m proved right, it will confirm the worthwhileness of all my blog trolling. If I am wrong - well, there’s still nothing wrong with idle entertainment.
Copyright © Ted C. MacRae 2011