Abstract
The leaching of a large amount of pollutants derived from agricultural and domestic activities (fertilizers, pesticides, detergents) might contaminate especially the aquatic environments affecting several non-target aquatic organisms such as crustacean species. The current study aimed to evaluate under laboratory conditions the potential side-effects of novaluron (20% Wettable Powder), a potent benzoylurea derivative insecticide on mosquito larvae, against a non-target shrimp, <i>Palaemon adspersus</i> Rathke, 1837 (Decapoda, Palaemonidae). This species is abundant in the lagoon El-Mellah (Northeast Algeria) and a relatively important species for the local fishery industry. The compound was tested at two concentrations (0.91 mg/L and 4.30 mg/L) corresponding respectively to the LC<sub>50</sub> and LC<sub>90</sub> determined against fourth-instar larvae of <i>Culiseta longiareolata</i> (Diptera, Culicidae). The newly ecdysed adult shrimps were exposed for 15 days, i.e. stage A until D during a moult cycle. Under normal conditions, changes in hemolymphatic ecdysteroid concentrations during the molting cycle presented a peak at stage D, just before the ecdysis while in the treated series, we note an increase in hemolymphatic ecdysteroid concentrations at stages C and D and an absence of the peak as compared to the controls. Histological observations of integuments revealed that novaluron caused a significant reduction in thickness of the new cuticle at its LC<sub>50</sub> and an inhibition of the new cuticle secretion at its LC<sub>50</sub>. The determination of chitin amounts, showed that exposure of shrimps to novaluron resulted in a significant decrease of values at all molting stages with a dose-response manner in comparison to controls. Thus, the overall data confirm the primary mode of action of novaluron on chitin. This insecticide can present secondary effects on this non-target shrimp species commercially important for the local economy.
Highlights
Conventional pesticides are widely used in crop production and very effective against target organisms [1]
The IGDs compounds can be grouped according to their mode of action, as follows: substances that interfere with the action of insect hormones and chitin synthesis inhibitors
Under normal conditions of P. adspersus, the titers of hemolymphatic ecdysteroids increased during the molt cycle to reach a peak at stage D, just before the ecdysis
Summary
Conventional pesticides are widely used in crop production and very effective against target organisms [1] They are known to make risks and impacts on human health and environment [2]. The IGDs compounds can be grouped according to their mode of action, as follows: substances that interfere with the action of insect hormones (i.e. juvenile hormones, ecdysteroids) and chitin synthesis inhibitors Among these they are several classes of the chitin synthesis inhibitors, such as pyrimidine-nucleoside peptides, benzoylurea, oxazolines, thiazolidines, tetrazines, thiadiazines, thiophthalimides and certain chromo- and fluorophores [5]. An intensive search for more potent benzoylurea derivatives from the prototype compound, diflubenzuron [7], has resulted in synthesis of several
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: International Journal of Environmental Monitoring and Analysis
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
