Temperature trends and advancing dates of emergence for montane grasshoppers along an elevational transect in the Colorado front range (1953-2008)

Climate change is having significant impacts on insect phenology, with warmer environmental temperatures contributing to a progression toward earlier emergence. This study investigates the relationship between climate change and montane grasshopper phenology. In 2006 and 2007, I surveyed adult emergence of grasshoppers at two montane sites in the Rocky Mountain Front Range of Colorado. These data were compared against the emergence dates from a survey conducted in 1959 and 1960 to assess the degree to which emergence dates have shifted over the last 50 years.;To develop the context for such a study, I analyze temperature trends along the RMFR transect from 1953 to 2006. I uncover widespread warming over the climatic record of the RMFR transect (1953-2006), and warming trends are shown to be amplified in recent decades. In accordance with measured warming at montane sites, the adult emergence of grasshoppers has advanced by approximately four days per decade since 1959, while each degree C corresponds to an advancement of roughly ten days. The grasshoppers' thermal (GDD) requirement has not changed significantly leading me to conclude that changes in emergence are the result of warmer temperatures.