The Australian Alps are a globally unique environment at the forefront of the most profound and substantial consequences of climate change, with stream temperatures predicted to increase by 3℃ within the century. As ectotherms, invertebrates are intrinsically linked with temperature; increases in temperature are known to drive changes in invertebrate development and size. We investigate the impact of temperature on the growth and development of an endemic alpine caddisfly species, Archaeophylax ochreus. Individuals were reared at four temperatures and their time until pupation, pupation duration, and emergence times were recorded. Additionally, we calculated and recorded the cumulative degree days (CDDs) at which these developmental stages occurred.
We found that while most results conformed expectations of a faster development at increasing temperatures and no change in CDDs across temperature treatments, individuals reared at the coolest temperature responded contrary to predictions for time until pupation. These individuals took the least number of days to reach pupation and experienced substantially fewer CDDs. Our results suggest that different mechanisms trigger the onset of pupation in the coldest verses the warmest environments. Moreover, non-significant changes in time until emergence suggest that future warming temperatures may not impact the seasonality of flying adults of this species; however, a high death rate in our warmer treatments points to lower biomass under future climates.