+ Site Statistics
+ Search Articles
+ Subscribe to Site Feeds
EurekaMag Most Shared ContentMost Shared
EurekaMag PDF Full Text ContentPDF Full Text
+ PDF Full Text
Request PDF Full TextRequest PDF Full Text
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter
Follow on Google+Follow on Google+
Follow on LinkedInFollow on LinkedIn

+ Translate

Trends in numbers of aquatic invertebrates in a large canadian river during 4 years of black fly larviciding with methoxychlor diptera simuliidae

Quaestiones Entomologicae 19(1-2): 53-92

Trends in numbers of aquatic invertebrates in a large canadian river during 4 years of black fly larviciding with methoxychlor diptera simuliidae

Methoxychlor was injected and maintained for 15 min .apprx. 0.3 ppm, into Saskatchewan River System in Saskatchewan once in 1976, 6 times in 1977, 7 in 1978, 19 in 1979 and 5 times in 1980. Severe outbreaks of S. luggeri originated from various portions of the river up to 200 km long during the first 3 yr, but not in 1979 or 1980. With suprageneric taxa serving as units, trends in numbers of non-simuliids were measured 1977-1980. Average densities of combined non-simuliid invertebrate populations attaching weekly to artificial substrates in mid-river sites in all 3 branches of the Saskatchewan River peaked in 1979 (P < 0.01) the year of maximum larvicide use, but in 1980 returned to just above the 1977 level. Average numbers of invertebrates in benthic samples from river margins also generally peaked in 1979 or 1980 in all 3 river branches. In 1 or more of the 6 locations sampled, numbers of certain families of Ephemeroptera (baetids, heptageniids, caenids, leptophlebiids and polymitarcyids), of Trichoptera (hydroptilids, leptocerids and brachycentrids), and of Diptera (simuliids, tanypodines, orthocladiines, tanytarsines and empids) declined after 1977 or 1978; in other locations many of these taxa peaked in 1979 or 1980. Some larvae dislodged by methoxychlor treatments apparently reattached in downstream sites. In 25-73% of 23 tests there were increases rather than decreases in numbers of various non-simuliid and simuliid taxa attaching to rope-piece substrates, 25-92 km downstream during the week following an injection. Significant upward trends in average annual densities of suprageneric taxa indicated that effects of methoxychlor treatments essentially were neutral when compared with effects of unidentified extrinsic ecological processes. Check lists of benthic species collected from all 3 rivers at the conclusion of tests in 1980 proved the survival of a varied fauna representing apparently complete ranges in feeding habits, activity patterns and life cycles. The relatively intensive series of methoxychlor larvicide treatments required to prevent damaging outbreaks of S. luggeri from the Saskatchewan River was not permanently harmful to non-simuliid taxa in the river, at least at the suprageneric level.

Accession: 006839448

Related references

Trends in numbers of aquatic invertebrates in a large Canadian river during four years of black fly larviciding with methoxychlor (Diptera: Simuliidae). Quaestiones Entomologicae, 191-2: 53-92, 1983

71 Diptera Author Index 1973 The effect of experimental blackfly Diptera Simuliidae larviciding with abate, dursban and methoxychlor on stream invertebrates. Canadian Ent, 1056: 817-831, 1973

The effects of experimental blackfly (Diptera: Simuliidae) larviciding with Abate, Dursban, and methoxychlor on stream invertebrates. Canadian Entomologist 105(6): 817-831, 1973

Acute and long term effects of methoxychlor larviciding on the aquatic invertebrates of the Athabasca River, Alberta. Control of black flies in the Athabasca River Technical report An interdisciplinary study for the chemical control of Simulium arcticum Malloch in relation to the bionomics of biting flies in the protection of human, animal, and industrial resources and its impact on the aquatic environment: 151-158, 1980

The influence of formulation on toxicity and availability of a pesticide methoxychlor to black fly larvae diptera simuliidae some nontarget aquatic insects and fish. Canadian Entomologist 113(4): 281-294, 1981

Tests with single injections of methoxychlor black fly (Diptera: Simuliidae) larvicides in large rivers. Canadian Entomologist 106(3): 285-305, 1974

Fluctuations in numbers of adult black flies (Diptera: Simuliidae) in Deep River, Ontario. Canadian Entomologist 104(9): 1465-1470, 1972

Field evaluation of the phototoxin, alpha-terthienyl, for reducing larval populations of the black flies (Diptera: Simuliidae) and its impact on drift of aquatic invertebrates. Canadian Entomologist 123(3): 439-449, 1991

Field evaluation of the phototoxin alpha terthienyl for reducing larval populations of black flies diptera simuliidae and its impact on drift of aquatic invertebrates. Canadian Entomologist 123(3): 439-449, 1991

A broad evaluation of B t i for black fly Diptera Simuliidae control in a Michigan river efficacy, carry and nontarget effects on invertebrates and fish. Journal of the American Mosquito Control Association, 53: 397-415, 1989