Tonight's selection was suggested for your viewing pleasure by Jack Longino.
Atta cephalotes Leafcutting ants of the genus Atta have perhaps the most complex caste systems of all the social insects.  Mature colonies contain millions of workers of varying shapes and sizes.  Here are two sisters from opposing ends of the spectrum. photo details: Canon MP-E 65mm 1-5x macro lens on a Canon EOS 20D ISO 100, f/13, 1/250 sec, flash diffused through tracing paper
Atta cephalotes carrying leaves, Ecuador Molecular Phylogenetics and Evolution this morning has the first detailed molecular phylogeny of the leafcutting ant genus Atta.  MaurÃcio Bacci et al sequenced several mitochondrial genes and the nuclear gene EF-1a from 13 of the 15 described species-level taxa, using them to infer the evolutionary history of the genus. This is an important paper.  Atta is the classic leafcutter ant of the new world tropics and a model system for co-evolution among the ants, the fungi they cultivate, and a suite of microbes that either parasitize or protect the…