Tundra ponds on the Arctic Coastal Plain near Barrow, AK produce a succession of synchronously-emerging insect species over a 3-4wk period during the short arctic summer. This pulse of aquatic productivity is crucial to tundra-breeding passerines, shorebirds, and waterfowl, and is readily recognized by local residents as an important ecological event in the regional landscape. Visiting researchers teamed with local educators and students to test the influence of varying thermal environments on rates of larval or pupal development in the chironomid species Derotanypus aclines and Trichotanypus alaskensis, and the stonefly Nemoura arctica. Mature larvae or early pupae were incubated in three habitats with differing mean temperatures but natural diel amplitudes, and monitored daily for adult emergence.
Results/Conclusions
In five independent trials with chironomids (two with Derotanypus, three with Trichotanypus), warmer temperatures produced faster pupal development and adult emergence. In a single trial with Nemoura larvae, temperature did not influence emergence timing. Chironomid emergence was not a linear function of “thermal time”, as more degree-days were experienced by the faster-developing pupae in the warmer treatments. Warmer temperatures may accelerate pre-emergence development of most insect species, resulting in compression of the emergence seasonal for the overall tundra pond community and a consequent shorter seasonal availability of insect prey. This simple field experiment provided active learning for local students, and generated information useful in predicting the response of arctic insect populations to climatic warming.
