Life history and production of the dominant Chironomidae in the New River, with emphasis on the effects of Bacillus thuringiensis var. Israelensis

The effects of Bacillus thuringiensis var. israelensis (Bti) on chironomid production was assessed in the New River in southern West Virginia. Production was measured in a year without Bti treatment (1987) and a year with treatment (1988). Sampling was conducted from June through November at Sandstone Falls, 16 km below Bluestone Dam in Summers County. Sampling was restricted to rock outcrops covered with Podostemum (river weed). Samples were collected at 2- wk intervals with a quantitative device that delineates an area of 0.01 m². Three species belonging to two genera accounted for about two-thirds of chironomid production in both years. Cohort production intervals were estimated to be 27 d for both species of Cricotopus and 20 d for P. convictum. Total chironomid production from June through November 1987 was 10.8 g/m² and during the same period in 1988 was 33.8 g/m². In 1987, the production of C. bicinctus and Cc. politus was 4.09 g/m² (38% of total chironomid production), and production of P. convictum was 2.46 g/m² (23%). In 1988, the production of C. bicinctus and C. politus was 12.39 g/m² (37%), and production of P. convictum was 11.38 g/m² (34%). Bti treatments caused no adverse effect on chironomid production in 1988, because the same species were dominant and their production was 3X higher. In addition, density and mean individual biomass were greater in 1988 than in 1987. The production increase in 1988 was probably related to environmental factors other than Bti treatments, such as discharge and Podostemum standing stock.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Entomology

Department dc:contributor.department

Entomology

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

1990

Author dc:creator

• Silvia, Antone G.

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Dc Identifier Other

etd-05092009-040337

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/42531