Skip to page content
USDA Forest Service

Research & Development Treesearch

Treesearch Home
About Treesearch
Contact Us
Research & Development
Forest Products Lab
International Institute of Tropical Forestry
Pacific Northwest
Pacific Southwest
Rocky Mountain
Southern Research Station
Help - We Participate  Government Made Easy

Global Forest Information Service

US Forest Service
P.O. Box 96090
Washington, D.C.

(202) 205-8333

You are here: Home / Search / Publication Information
Bookmark and Share

Publication Information

View PDF (350k bytes)

Title: Bacterial growth on stream insects: potential for use in bioassessment

Author: Lemly, A. Dennis;

Date: 1998

Source: Journal of North American Benthological Society. 17(2):228-238.

Publication Series: Miscellaneous Publication

Description: Growth of filamentous bacteria (Sphaerotilus sp., Leptothrix sp.) on aquatic insects was evaluated for its usefulness as a bioindicator of detrimental nutrient levels in streams. Field measurements of insect abundance, nutrient concentrations, and incidence/ degree of bacterial growth on insects upstream and downstream of livestock pastures were made in 2 Virginia, USA streams. Laboratory studies were conducted to determine the effect of bacterial growth on insect survival. Elevated concentrations of dissolved nutrients (0.13 to 0.35 mg/L orthophosphate, 1.29 to 2.13 mg/L nitrate) downstream of pastures were associated with growth of filamentous bacteria, which colonized the gills and body surface of aquatic insects. Significantly lower densities of insects (up to 66 percent less) occurred at downstream sites. In laboratory studies, 100 percent mortality of heavily infested mayflies (>25 percent of body covered, including gills) occurred within 30 days, whereas >85 percent of individuals without bacterial growth survived and grew normally. The pattern of mortality in the laboratory closely paralleled the differences in density observed in the field. Bacterial growth on aquatic insects appears to be a reliable bioindicator of nutrient enrichment, and the degree of infestation associated with reduced insect survival can be quickly detected in the field or laboratory using a hand lens (10 to 15X magnification). This bioindicator shows promise as a significant addition to EPA Rapid Bioassessment Protocols because simple visual assessment of benthic samples may be sufficient to identify a cause for impaired macroinvertebrate communities. Bacterial growth should be useful for detecting nutrient impacts in streams, as well as evaluating the success of management practices to control nutrients from point or non-point sources

Publication Notes:

  • We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
  • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
  • You may send email to to request a hard copy of this publication. (Please specify exactly which publication you are requesting and your mailing address.)



Lemly, A. Dennis 1998. Bacterial growth on stream insects: potential for use in bioassessment. Journal of North American Benthological Society. 17(2):228-238.


 [ Get Acrobat ]  Get the latest version of the Adobe Acrobat reader or Acrobat Reader for Windows with Search and Accessibility

USDA logo which links to the department's national site. Forest Service logo which links to the agency's national site.