Food Habits for Mayflies (Ephemeroptera) in Two Streams of Contrasting Habitat Type in Central Texas
Date
1987-07
Authors
Harrison, James W.
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Abstract
Food habits for mayflies in two streams from the same drainage basin.in south-central Texas were studied for a period of one year. The apparent similarity of resource use within and the significant differences between clearly suggests that available resources are partitioned between two functional guilds in each stream. Significantly higher proportions of diatoms in the diet of scraper-collectors (Annual mean=40% in Honey Creek;13% in the Blanco River), relative to gatherer-collectors (Annual mean=144% in Honey Creek) and collector-filterers (Mean=3% in the Blanco River), shows that the scraper-collector guild primarily utilizes the organic film on the surface of the substrate. The low percentages of algae in the diet of gatherer-collectors and collector-filterers demonstrates that these groups primarily use loose particulate fine detritus in interstitial spaces or in the water column. Scraper-collectors were found to dominate the mayfly community in the canopied headwaters site (834 of total biomass), while collector-filterers were the most important at the mid-reach site (79% of total biomass).
The distinctly different diets observed for congeneric insects from these two streams reflects the importance of environmental variables in shaping energy flow pathways. However, results also suggest that density dependent factors may affect resource availability to these mayflies.
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Keywords
mayflies, stream ecology
Citation
Harrison, J.W. (1987). Food habits for mayflies (Ephemeroptera) in two streams of contrasting habitat type in Central Texas (Unpublished thesis). Southwest Texas State University, San Marcos, Texas.