Biology of Hypogastrura tullbergi (Collembola) at a high arctic site

The life cycle, reproductive biology and growth rates of Hypogastrura tullbergi (Schäffer), one of the most abundant and widespread Collembola on Devon Island, N.W.T., were investigated.
Reproductive activity was confined to a period of 2–4 wk every season, starting approximately 2 wk after snow-melt. Individuals of H. tullbergi had the potential of breeding in at least 2 successive summers. This species had an extended, flexible life cycle with a total life span of approximately 3 yr.
Growth rates of individuals of H. tullbergi maintained at field temperatures with an excess of fungal material greatly exceeded growth rates of individuals in the field population. It is suggested that in the field, growth rates are limited by food rather than directly by low temperatures.
H. tullbergi was not able to grow on a diet of decomposing Dryas integrifolia leaves. Growth rates on fungal substrates were found to depend on temperature, species of fungus, and age. Maximum growth rates for adults occurred at 10°C, but juveniles showed a maximum growth rate at 15°C.
The adaptive significance of aspects of the biology of H. tullbergi for long-term survival in tundra environments is discussed.