Using pre-Quaternary Diptera as indicators of paleoclimate

We found that using a MCR approach with fossil Diptera can provide an estimate of paleoclimate for pre-Quaternary assemblages that is consistent with estimates made by paleobotanists. The analysis that included all Diptera gave a less precise climate estimate (12-18 °C) than the analysis in which host-dependent taxa were omitted. Our climate estimate, based on only non-host-specific taxa, was 12-14 °C, which is well within the range of estimates for Florissant derived from floral material. Although approaches that use modern analogs are sometimes viewed with concern because of the necessary assumption that fossil taxa share the same environmental tolerances as their modern counterparts, we believe that fossil insect assemblages, especially when used in MCR analyses, can be quite informative in estimating pre-Quaternary paleoclimate.