(2004) observed that Chaoborus obscuripes (Diptera: Chaoboridae
) was the species most sensitive to lambdacyhalothrin ([CE.sub.50(48and96h)] = 0.0028 [micro]g [L.sup.-1]), followed by other insect larvae of the orders Hemiptera and Ephemeroptera and macrocrustaceans, which were relatively sensitive ([CE.sub.50(48and96h)] = 0.01-0.1 [micro]g [L.sup.-1]).
Predation by water mite (Cassano et al., 2002) and Chaoboridae
larvae has emerged as the most important factor in structuring the Zooplankton community (Arcifa et al., 1992, 2015; Arcifa, 2000; Castilho-Noll and Arcifa, 2007a, b), whose impact is stronger during the wann season (Arcifa et al., 1992, 2015), and influencing the vertical migration of microcrustaceans (Minto et al., 2010).
Sampled sites Food items 1 2 3 4 n = 38 n = 41 n = 61 n = 129 Detritus/sediment 19.633 30.207 85.123 25.713 Plants remains 6.752 7.830 20.194 1.581 Algae 4.176 - 32.746 - Insect remains Formicidae - 0.030 - - Insect larvae Coleoptera - - 0.003 - Elmidae - 0.006 - - Chaoboridae
- 0.097 - - Simuliidae 0.074 - - - Chironomidae 0.070 6.273 0.413 0.026 Trichoptera 0.002 - - - Fish remains - - 0.134 - (scales and bones) Table 3.
Finally, highly sensitive organisms such as the larvae of the top predator phantom midges (Chaoboridae
) were observed in high densities, and algae almost disappeared completely.
(Parma 1971; Moom 1986; Irvine 2000), Chironomidae (Gibson 1945; Young 1969; Oliver 1971; Paasivirta 1972; Kon 1987; Fyodorova & Azovsky 2003), Culicidae (Horsfall 1955; Nielsen et al.
The Novo Lake showed the highest density of organisms, with average and standard deviation of 1879 [+ or -] 3166 ind.[m.sup.-3] of Rotifera, Cladocera (207 [+ or -] 412 ind.[m.sup.-3]), Copepoda (870 [+ or -] 44 ind.[m.sup.-3]) and Chaoboridae
(0 [+ or -] 1.0 ind.[m.sup.-3]).
Atraves da analise de organismos bentonicos, foram encontradas somente tres familias (Chironomidae, Chaoboridae
e Naididae), todas pertencentes a ordem Diptera, porem foi possivel detectar variacoes em relacao a diversidade (indice de Shannon-Wiener) entre as estacoes amostrais.
Nearctic and palaearctic Chaoborus (Diptera: Chaoboridae
Vertical migration of Chaoborus flavicans (Diptera, Chaoboridae
): control of onset of migration and migration velocity by environmental stimuli.
and Chironomidae) and Ephimeroptera form the lake fly group commonly eaten within the lake region.