Toxicity of Fipronil to the Midge,Cricotopus lebetisSublette

Abstract

Fipronil, a relatively new insecticide more recently developed than organophosphates and pyrethroids, has been detected in surface water draining from agricultural and urban-developed areas. This insecticide is primarily lost through subsurface and surface drainage from terrestrial areas where it has been applied. Invasive aquatic plants often need to be managed in these receiving water bodies to prevent loss of recreational and functional values (e.g., drainage), especially in subtropical and tropical areas. One insect of particular interest is the chironomid midge Cricotopus lebetis Sublette, which may be a useful augmentative biocontrol agent for the invasive aquatic weed Hydrilla verticillata L.f. Royale. Exposure of aquatic organisms, especially insects, to fipronil may significantly impact nontarget populations. These studies investigated the sensitivity of C. lebetis to fipronil exposures ranging from 24 to 96 h. The LC50 observed for each exposure interval was 7.26 μg/L (24 h), 2.61 μg/L (48 h), 1.78 μg/L (72 h), and 1.06 μg/L (96 h). The LC90 values observed were 47.18 μg/L (24 h), 9.55 μg/L (48 h), 6.45 μg/L (72 h), and 4.81 μg/L (96 h). Behavioral changes were seen at all fipronil concentration levels, where larvae exited the plant and exhibited abnormal behavior, such as restricted movement and lack of feeding. Results indicate that acute lethality occurred at environmentally relevant concentrations of fipronil.

Effects of insecticides, fipronil and imidacloprid, on the growth, survival, and behavior of brown shrimp Farfantepenaeus aztecus

“…Similarly, Stratman et al . [82] showed that the chironomid midge Cricotopus betis exposed to different concentrations of fipronil exhibited abnormal behaviors such as movement restriction and feeding reduction at all tested concentrations. Behavioral changes could be direct consequences of pesticides on the central nervous system of organisms [83].…”

Lethal and sub-lethal effects of the insecticide fipronil on juvenile brown shrimp Farfantepenaeus aztecus

“…For example, Stratman et al . 27 showed that the chironomid midge Cricotopusle betis Sublette exposed to fipronil exhibited abnormal behaviors, movement restriction, and feeding reduction. Overmyer et al .…”

“…Fipronil can flow into creeks, rivers, and estuaries because it is mobile in soils and soluble in water 24 . Many recent studies have demonstrated the occurrence of fipronil and its degradation products, which have the same or greater toxic properties and are more stable than fipronil itself 21 , 25 – 27 , in the aquatic environment at levels ranging between 0.001–10.004 µg/L, often exceeding the acute level (0.1 µg/L) of fipronil in the aquatic life benchmark of the U.S. EPA 22 , 28 – 31 . A nationwide survey from 2002 to 2011 conducted by Stone et al .…”

Immunological and antioxidant role of curcumin in ameliorating fipronil toxicity in Nile tilapia ( Oreochromis niloticus )

“…In addition, FIP metabolites, as sulphide and sulphone are more toxic than FIP itself (Wang et al, 2018). Many recent readings have tested the toxicity of FIP in aquatic ecosystem varying among 0.001-10.004 μg/L (Stratman et al, 2013).…”