In September and October of 2014, three members of the Department of Entomology headed to Brazil: Ted Schultz, Ana Jesovnik and Jeffrey Sosa-Calvo. We all work in the department’s Ant Lab, Ted as a curator and Ana and Jeffrey as graduate students from the University of Maryland. We spent 35 days driving a rental car 4700 km (2,920 miles) across the entire country of Brazil. During our travels we collected hundreds of ant species, but our real mission was to track down a rare and elusive fungus-farming ant species. Fungus-farming ants grow and eat fungus gardens and some of the primitive species are very rare.
One of the places we visited was Chapecó National Forest (Floresta Nacional do Chapecó in Portuguese) in Santa Catarina state. We were there with a singular goal: To find and collect the elusive fungus-farming ant species Mycetosoritis asper. This species was described in 1887 from a single specimen collected in Santa Catarina. Only two more specimens have been collected since then. Worker ants of Mycetosoritis asper are beautiful and tiny, only 4 mm long, pale yellowish-brown in color, and have spines and hairs on their bodies. Because M. asper looks very different from other fungus-farming ants, no one really knows where it fits into the fungus-farming ant tree of life. Since nests have never been collected, no one knows what kind of fungus it grows.
Even though we had tried twice before, we had never previously been able to find nests of M. asper. But this time was different because we had permits to collect inside of Chapecó National Forest. Although the state of Santa Catarina was once covered by a lush semi-tropical forest, today, sadly, Chapecó National Forest contains one of the last remnants. Within 10 minutes of entering the forest, we got lucky. We found a nest of M. asper! It was just a tiny hole in the ground with a tiny ant coming out of it, but we found it. Over the next few days we were able to dig up 20 nests of this no-longer rare ant.
Each nest had a chamber containing a fungus garden, a queen, workers, and larvae (baby ants) around 30-60cm (1-2 ft) below the surface. The colonies we excavated in October (Brazilian spring) did not contain winged males or winged daughter queens, which are only produced once each year. However, we were able to obtain permits to bring live colonies back to the Ant Lab in the Smithsonian National Museum of Natural History. Last week (Brazilian autumn) some of the nests produced males and alate (winged) queens here at the Smithsonian. Males of this species have never been seen before, so we are eager to describe them for the first time.
Ana Jesovnik, Jeffrey Sosa-Calvo, and Ted Schultz. Ant Lab, Department of Entomology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.