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Presented at the NABS Annual meeting, Pittsburgh, Pennsylvania, 2002
in Life Histories
LARVAE OF AN ARCTIC MAYFLY SHOW RAPID GROWTH AT COOL TEMPERATURES.
A.D. Huryn1, S.M. Parker1, and B.J. Peterson2. 1Department of Biological Sciences, University of Maine, Orono, ME 04469, 2The Ecosystems Center, Marine Biological Laboratory, Woods Hole, MA 02543
The Kuparuk River, Alaska (68°38’N), is the site of an 18 year study of the effects of phosphorous fertilization on ecosystem processes of an Arctic stream. The effects of the fertilization are numerous and are generally related to increased primary productivity. As part of a study of consumer response to fertilization, we measured growth rates (mg mg-1 d-1) of Acentrella (Baetidae), a common grazer in the Kuparuk. Mean growth rates ranging from 14 to 17% d-1 occurred within the relatively cool temperature range of 7 to 10°C. Growth rates of some individuals exceeded 24% d-1. The fertilization treatment had no significant effect on growth rates. Growth rates as high as 27% d-1 at temperatures >25°C have been documented for baetid mayflies in subtropical and temperate latitudes. When measured at temperatures similar to the Kuparuk during summer, however, growth rates of baetids from these latitudes are usually <4% d-1 and do not exceed 6% d-1. The results of our study indicate that cohort production and turnover rates for some Arctic stream insects may be similar to those expected for communities at much lower latitudes. We speculate that rapid growth of Acentrella in the Kuparuk is an adaptation to short Arctic summers.
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