Midge larvae

Bervoets, L., R. Blust, and R. Verheyen. 1996. Effect of temperature on cadmium and zinc uptake by the midge larvae Chironomus riparius. Arch. Environ. Contam. Toxicol. 31 502-511. 

Since persistence in sediments is longer than that in the water column, the relevant toxicity studies are those that consider longer term, chronic exposures. A number of standard tests have been developed for assessing sediment toxicity and the bioassay of field collected sediments (e.g., [16-24]). The most commonly tested freshwater species are arthropods, including the amphipod shrimp // azteca and chironomid midge larvae, both Chironomus dilutus (formerly C. tentans) and C. riparius. Water-only studies have demonstrated that II. azteca are particularly sensitive to SPs (see Sect. 3) and in the published literature, this is the most commonly tested species for assessing the sediment toxicity of SPs. 

P. promelas, the midge larva C. riparus, the crustacean D. magna and the water snail L. stagnalis were obtained. When the bioassays were carried out with surface water, the determined NOECs were higher, with this fact a consequence of the suspended matter in the water [127]. 

Experiments in this study, done exclusively with midge larvae, include 1) 24-hr toxicity data for representative insecticides, with and without synergists 2) in vivo absorptive uptake and metabolic studies of aldrin and dieldrin, with and without piperonyl butoxide (PBO) 3) body depuration rate (loss to water) for dieldrin 4) determination of optimal in vitro... 

In Step 1, an incubation mixture (11) was tested using 20 midge larvae homogenized in 8.3 X 10-2 M Tris-HCl buffer, pH 7.5. Each 5 ml incubation mixture contained 20 homogenized midges,... 

Insecticide Absorption, Conversion and Depuration. Midge larvae immersed in 20 ug/L aldrin for 2 hr absorbed 25.4 ng of insecticide per larva, converting 58% of it to dieldrin (Table II). With 1.0 mg/L PBO present, midges absorbed 18.4 ng of aldrin per larva, but no aldrin was converted to dieldrin. With or without PBO, midge larvae absorbed dieldrin at the same rate as aldrin (Table II). 

All insecticides affected the mobility of . riparius larvae in a similar manner. A normal swimming motion was generally reduced to 1 cycle at the onset of toxic symptoms. The effect of the toxicant increased until the larva lost all ability to move. Death soon followed. Similar symptoms of insecticide poisoning have been reported for stonefly naiads (13, 14). Changes in larval color were unreliable for determining toxic affect. Toxic symptoms were observed in approximately 50-75% of the midge larvae immersed in 20 ug/L aldrin at the end of the 2 hr exposure but no effects were noted with aldrin plus PBO. All larvae immersed in dieldrin, or dieldrin with PBO were moribund. 

The depuration of dieldrin from midge larvae was relatively slow (Table III). Larvae transferred to clean water for 3 hr released 0.011 ng of dieldrin/larva/hr, or 0.2% of the total dieldrin absorbed. Another group of larvae transferred to clean water for a total of 6 hr, released dieldrin to the water at approximately the same rate, 0.014 ng/larva/hr, or 0.5% of the total dieldrin absorbed. 

Midge larvae rapidly accumulate aldrin or dieldrin and readily epoxidize aldrin to dieldrin without further conversion. 

Deepwater Nematodes, amphipods, copepods, oligochaetes Crayfish, clams, oligochaetes, gastropods, isopods, midge larvae... 

Dad, N.K. and P.S. Tripathi (1980). Acute toxicity of herbicides to freshwater fish and midge larvae. Chironomus tentans Environ. Int., 4 435 137. 

Bervoets, L., Meregalli, G., De Cooman, W., Goddeeris, B. and Blust, R. (2004) Caged midge larvae Chironomus riparius) for the assessment of metal bioaccumulation from sediments in situ, Environmental Toxicology and Chemistry 23 (2), 443-454. 

Sae-Ma, B., Meier, P.G. and Landrum, P.F. (1998) Effect of extended storage time on the toxicity of sediment-associated cadmium on midge larvae Chironomus tentans), Ecotoxicology 7 (3), 133-139. Sakai, M. (2001) Chronic toxicity tests with Daphnia magna for examination of river water quality,... 

Belden JB, Lydy MJ. 2006. Joint toxicity of chlorpyrifos and esfenvalerate to fathead minnows and midge larvae. Environ Toxicol Chem 25 623-629. 

Temephos is an insecticide for control of mosquito and midge larvae. Its oral LD50 in rats is 4,204-10,000 mg/kg. 

Fig. 5.8. Gall midge larvae (without feet, orange) feed on aphids.

Lamb, D.S. and Bailey, G. Acute and chronic effects of alum to midge larvae. Bull. Environ. Contam. Toxicol., 27, 59-67, 1981. 

At least 150 mm deep for organisms over 0.5 g each and at least 50 mm deep for smaller organisms Feed at least once a day a food that will support normal function Daphnids and midge larvae 48 h... 

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