Sort of off-topic, though.
Our paper: Peña & Wahlberg (2008) Prehistorical climate change increased diversification of a group of butterflies. Biology Letters; is
Here is the doi link: 10.1098/rsbl.2008.0062
and here links to the PDFs: http://nymphalidae.utu.fi/publi.htm
From the abstract:
Satyrinae butterflies (Lepidoptera: Nymphalidae) and grasses (Poaceae) are very diverse and distributed worldwide. Most Satyrinae use grasses as hostplants, but the temporal scale of this tight association has been unknown. Here we present a phylogenetic study of Satyrinae butterflies and related groups, based on 5.1 kilobases from six gene regions and 238 morphological characters for all major lineages in the “satyrine clade”. Estimates of divergence times calibrated using a fossil from Late Oligocene indicate that the species rich tribe Satyrini diversified to its current 2,200 species simultaneously with the expansion and radiation of grasses during the dramatic cooling and drying up of the Earth in the Oligocene. We suggest that the adaptive radiation of grass feeders in Satyrini was facilitated by the ubiquitousness of grasses since 25 Mya, which was triggered by a change in global climate.