Title

Baseline incidence of mouthpart deformities in Chironomidae (Diptera) from the Laurentian Great Lakes, Canada

Source of Publication

Journal of Great Lakes Research

Abstract

Larval chironomid mouthpart deformities are used as indicators of anthropogenic stress. However, there are limited data on the incidence of naturally occurring deformities. Chironomid larvae were collected from 252 reference sites throughout the Great Lakes by Environment Canada from 1991 through 1993. Overall incidence of mentum deformities was 2.27% for Procladius (SE = 0.46, n = 1055), 2.15% for Chironomus (SE = 0.51, n = 839), 1.27% for Heterotrissocladius (SE = 0.57, n = 393), 1.38% for Tanytarsus (SE = 0.61, n = 363), and 3.25% for Polypedilum (SE = 1.07, n = 277). The most common deformity was one missing tooth in the mentum. Deformity frequency was highest in Northern Channel and Georgian Bay of Lake Huron. However, incidences were homogeneous among regions (G-test, p > 0.05). In examining contaminated conditions, a result greater than one 95% confidence interval above these reference deformity frequencies should be considered significantly elevated from baseline levels.

Document Type

Article

First Page

172

Last Page

180

Publication Date

1-1-2003

DOI

10.1016/S0380-1330(03)70425-0

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