Exposure-dependent variation in cryolite induced lethality in the nontarget insect, Drosophila melanogaster

Abstract

The starting point of toxicity testing of any chemical in an organism is the determination of its Lethal Concentration 50 (LC50). In the present study, LC50 of a fluorinated insecticide cryolite is determined in a non-target insect model, Drosophila melanogaster. Interestingly, the result shows that acute LC50 of cryolite was much greater in comparison to the chronic one in case of Drosophila larvae. Larvae which were exposed to 65,000 to 70,000 µg/ml cryolite through food showed 50% mortality after 18 hours of acute exposure, whereas only 150 to 160 µg/ml cryolite was sufficient to cause 50% mortality in case of chronic exposure. Thus cryolite in a small amount when applied once cannot produce noticeable changes in Drosophila, whereas the same amount when used continuously can be fatal. The non-feeding pupal stage was also seen to be affected by chemical treatment. This suggests that the test chemical affects the developmental fate and results in failure of adult emergence. Absence of chemical-induced mortality in adults assumes that the toxicity of cryolite might be restricted to the preimaginal stages of the organism. Reduction in body size of larvae after ingestion of cryolite (with food) in acute treatment schedule is another interesting finding of this study. Some individuals consuming cryolite containing food cannot survive whereas the few survivors manifest a significant growth retardation which might be due to a tendency of refusal in feeding. Hence the present findings provide a scope of assessment of risk of other similar non-target groups.

Toxicological Evaluation of a New Lepidopteran Insecticide, Flubendiamide, in Non-Target Drosophila melanogaster Meigen (Diptera: Drosophilidae)

“…3). In course of the determination of chronic LC50 values, the study also demonstrated results very close to the nature of findings on the effects of a fluoride chemical [13], where the chronic LC50 values for larvae, pupae, and adult flies were much lower compared to that of acute values (Fig 5). The reason behind such observation might be because higher concentrations of this chemical are essential to cause both physical and physiological damage in a short period of time which might result in death of the individuals.…”

“…LC50 determination was performed following the method [13] with some modifications. Different concentrations of flubendiamide (TATA TAKUMI ® , Rallis, India) were made in distilled water, mixed with SDM and poured in Petri dishes (diameter -9 cm) for feeding and maintenance of larvae, pupae, and adult flies.…”

Anti-biofilm Activity of Extracts of Caryota no in Drosophila melanogaster Infected with Pseudomonas aeruginosa

“…From the LC 50 values [16] and the 28-days survival curves [17], appropriate doses (350, 400 and 500 mg/10 g food) were selected for further studies. These extracts were weighed in dried crystalline form for the methanolic extract and as an oily liquid for the nhexane extract and incorporated into fly food at the appropriate doses.…”

Toxicity Assay of Methanolic Extract of Caryota No Seed using Drosophila melanogaster Model

“…The starting point in determination of the safety profile of any compound is in the determination of its lethal concentration (in acute or chronic conditions) and also to check other toxicological parameters using experimental animals or insects. Lethal Concentration 50 or LC 50 is a standard measure of toxicity to determine how much of a substance is needed to kill half of a group of experimental organisms in a given time [7]. These preclinical studies must be undertaken before any biologically active substance must be evaluated clinically for therapy.…”