| |
Presented at the NABS Annual meeting, Pittsburgh, Pennsylvania, 2002
in Life Histories
EFFECT OF TEMPERATURE AND SESTON QUALITY OF GROWTH RATES AND PRODUCTION OF OVERWINTERING LARVAL BLACK FLIES.
J.S. Strike and A. Morin. Department of Biology, University of Ottawa, Ottawa, Ontario, Canada K1N 6N5
Larvae of Prosimulium mixtum/fuscum, Stegopterna mutata, and Simulium vittatum were repeatedly sampled form 9 sites between October 1985 and April 1986 to estimate individual growth rates and population production, and to test whether growth and production varied among sites in response to differences in seston quality (percent organic matter, chlorophyll contents of seston). Growth rates were estimated by following quantiles of the size distribution on consecutive sampling dates when no first instars were detected and no pupae were found. Regression analyses were performed to test whether growth rates, corrected for larval size and water temperature, increased with increases in seston quality. As expected, growth rates of the three species were found to be positively related to seston quality. However, the positive effect of seston quality on growth rates was small compared to the negative effect of individual size and positive effect of water temperature (between 0 and 2 degrees Celsius). Production of larval population over the winter was much more strongly related to seston quality than was growth. These results suggest that, although growth rates are affected by seston quality for these filter-feeders, seston quality may affect mortality more than growth.
|
|
