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Combined effect of three insect growth regulators on the digestive enzymatic profiles of Callosobruchus maculatus (Coleoptera: Bruchidae)
Abstract
Insect growth regulators (IGRs) are insecticides that mimic insect produced hormones by regulating developmental process. They have little or no mammalian toxicity, and are considered reduced-risk insecticides that are often exempt from tolerance requirements of regulatory agencies. IGRs, especially, chlorfluazuron, hydroprene and hexaflumuron (benzoylphenylurea) are currently studied because of possibility of using in stored products protection. Many of IGRs compounds used in insect pests control are known to affect digestive enzymes. Chlorfluazuron, hydroprene and hexaflumuronwere tested topically at doses of 0.25%, 0.5% &1% for chlorfluazuron and hydroprene and 0.5, 1& 2µg/ml of hex-aflumuron to investigate its effects on the activities of the digestive enzymes prote-ase, amylase and lipase in Callosobruchus maculatus larvae, which were affected by IGRs individually and in combination. When combined, the effect was more sever at low concentration. There were statistically significant differences (P≤ 0.05) in enzyme activities in combined and individual treatments. Combination three IGRs caused a twofold decrease in enzyme activity even at reduced concentration. Clear dose-response relationships were established with respect to enzyme activity. A synergistic effect of IGRs was found by combination of low doses. These effects are most pronounced in early instars.
... Our results relived that IGRs affect the activity of digestive enzymes of house fly. This findings agree with several studies indicating that IGRs disturb the activity of digestive enzymes of other insects, such as Pseudaletia separata (Huang et al., 2008) and Callosobruchus maculatus larvae (Khatter & Abuldahb, 2011). Also, methoxyfenozide and pyriproxyfen inhibited the activity of AChE and GE of M. domestica larvae. ...
Background
Housefly causes a variety of health problems to humans and animals. Therefore, it is crucial to find out effective methods for the control of housefly larvae to avoid health problems associated with the presence this disease vector insect. Efficacy of insect growth regulators (IGRs), chlorfluazuron, lufenuron, methoxyfenozide and pyriproxyfen, against larvae of Musca domestica (Diptera: Muscidae), was assessed. The IGRs were mixed with food media at concentrations of 2.5, 5.0, 10.0, 25.0, 50.0, 75.0 and 100.0 mg/kg (ppm).
Results
The highest larvicidal activity was obtained by chlorfluazuron and pyriproxyfen with LC 50 values of 6.79 and 7.10 ppm, respectively, 72 h post-treatment. Also, 25.0 ppm of chlorfluazuron and 75.0 ppm of methoxyfenozide as well as lufenuron were shown to fully suppress adult emergence and survival percentages (0.0%). Moreover, the activity of three digestive enzymes suppressed in the treated larvae with pyriproxyfen and chlorfluazuron: amylase (enzyme ratio (ER) = 0.71 and 0.78), lipase (ER = 0.54 and 0.63) and proteases (ER = 0.62 and 0.66), respectively. Also, methoxyfenozide and pyriproxyfen inhibited acetylcholinesterase (AChE) and general-esterase (GE) activity with ER (0.28 and 0.59) and (0.61 and 0.72), respectively. The histological examination of M. domestica larvae treated with IGRs showed changes in midgut; for example, the epithelial cells were broken, deformed and loss their columnar structure. Also, the peritrophic membrane disappeared completely.
Conclusions
The findings of the current study indicate that the tested IGRs have a potential to be applied in IPM programs of M. domestica .
... Table 3 also, showed that the activity of protease is decreased in all treatments compared with control especially in pyriproxyfen treatments. Significant reduction in the activities of protease in Callosobruchus maculatus larvae treated by insect growth regulators [21]. This decreasing of enzyme activity may be due to 13 decrease of feeding larvae. ...
Toxicity of three insect growth regulators; pyriproxyfen (juvenile hormone mimic), methoxyfenozide (an ecdysone agonist) and
lufenuron (chitin synthesis inhibitors) were assayed against the first instar larvae of pink bollworm under laboratory condition. Data
showed that lufenuron was the most toxic insecticides followed by methoxyfenozide and pyriproxyfen. The LC50 was 20.6, 47.4 and
50.8 ppm, respectively. The biological aspects (larval duration, pupal period, adult longevity, sex ratios, number of laid eggs and
hatchability) were affected also by the tested insecticides. Lufenuron was the most effective on biological aspects than other
insecticides. The life span of this insect was prolonged to 62.6 days compared to 49.7, 56.7 and 53 days with methoxyfenozide,
pyriproxyfen and control, respectively. The number of laid eggs per female and hatchability were affected in lufenuron followed by
pyriproxyfen and methoxyfenozide. Biochemical characterization showed that the activities of chitinase and protease were decreased
compared to control, while amylase activity increased. These results confirmed that chitinase, protease and amylase play an important
role in metabolism and degradation of insect growth regulators and thus play a major role in insect growth regulators resistance.
... Table 3 also, showed that the activity of protease is decreased in all treatments compared with control especially in pyriproxyfen treatments. Significant reduction in the activities of protease in Callosobruchus maculatus larvae treated by insect growth regulators [21]. This decreasing of enzyme activity may be due to 13 decrease of feeding larvae. ...
Toxicity of three insect growth regulators; pyriproxyfen (juvenile hormone mimic), methoxyfenozide (an ecdysone agonist) and
lufenuron (chitin synthesis inhibitors) were assayed against the first instar larvae of pink bollworm under laboratory condition. Data
showed that lufenuron was the most toxic insecticides followed by methoxyfenozide and pyriproxyfen. The LC50 was 20.6, 47.4 and
50.8 ppm, respectively. The biological aspects (larval duration, pupal period, adult longevity, sex ratios, number of laid eggs and
hatchability) were affected also by the tested insecticides. Lufenuron was the most effective on biological aspects than other
insecticides. The life span of this insect was prolonged to 62.6 days compared to 49.7, 56.7 and 53 days with methoxyfenozide,
pyriproxyfen and control, respectively. The number of laid eggs per female and hatchability were affected in lufenuron followed by
pyriproxyfen and methoxyfenozide. Biochemical characterization showed that the activities of chitinase and protease were decreased
compared to control, while amylase activity increased. These results confirmed that chitinase, protease and amylase play an important
role in metabolism and degradation of insect growth regulators and thus play a major role in insect growth regulators resistance.
... Higher digestive enzyme activities in control specimens indicated higher consumption of food because enzyme production depends on the amount of food that passes through the alimentary canal and the physiological condition of animal. According to Khatter and Abuldahb (2011), IGRs namely chlorfluazuron, hydroprene and hexaflumuron produced dose-related inhibition of protease, amylase and lipase in the larva of Callosobruchus maculatus (Coleoptera). Similarly, Shanthy et al. (1995) showed that JH analogues hydroprene and methoprene inhibited digestive enzyme activity in Tribolium castaneum (Coleoptera), especially amylase and invertase, apparently due to low food consumption by the treated insects. ...
The insect growth regulator (IGR) chemicals are considered as safe alternatives to synthetic organic pesticides, but only scant information are available on their possible impact on non-target and ecologically important soil insect fauna of croplands. Previous studies by the authors showed that recommended agricultural doses of IGRs buprofezin (Applaud 25SC at 250 g a.i. ha(-1)), flubendiamide (Takumi 20WG at 50 g a.i. ha(-1)) and novaluron (Rimon 10EC at 100 g a.i. ha(-1)) produced less mortality of adults of a non-target soil insect Cyphoderus javanus Borner (Collembola) but decreased major life history parameters namely moulting, fecundity and egg hatching success. This detritivorous microarthropod is very sensitive to soil characteristics and is ecologically relevant to the tropical soils. Present microcosm study showed strong biochemical impact of the above doses of IGRs on tissue nutrient levels and digestive enzyme activities in C. javanus within 7 days of exposure to treated sandy loam soil. The levels of tissue proteins, carbohydrates, lipids and free amino acids declined significantly and persistently in the specimens reared in IGR-treated soils than in the specimens of untreated soil. Similarly, α-amylase, cellulase and protease activities declined significantly in the specimens of IGR-treated soil. These nutritional scarcities would reduce metabolism, growth and reproduction in the affected insects. Therefore, the observed biochemical responses, especially the levels of tissue proteins, carbohydrates and α-amylase activity in C. javanus are early warning indices and potential biomarkers of soil pollution in croplands.
... Insect growth regulators (IGRs) are produced naturally by insects to regulate the processes of molting and development from the egg to the adult stage [4]. Pyriproxyfen is a pyridine-based juvenile hormone analogue that competes for juvenile hormone binding site receptors in insects, mimicking the action of juvenile hormone and thus maintaining an immature state [5]. ...
Insect growth regulators and microbial insecticides are mostly used in pest management since they are nontoxic to other organisms and have short half-life in the environment. Effects of juvenile hormone analogue pyriproxyfen and Bacillus thuringiensis on antioxidant enzyme (catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx)) activities of hemolymph, midgut and fat body of Galleria mellonella larvae was investigated. Larvae were exposed to LD50 values of pyriproxyfen and B. thuringiensis (LD50 of B. thuringiensis: 359 mg/L; LD50 of pyriproxyfen: 2385 mg/L), then enzyme activities were measured spectrophotometrically after 72 hours from treatment. When LD50 value of pyriproxyfen and B. thuringiensis were applied to G. mellonella larvae singly and in mixture, the activities of SOD, CAT and GPx were significantly increased in hemolymph and fat body of G. mellonella larvae, whereas the enzyme activities were significantly decreased in midgut of larvae compared with the control group. As a result of this study, we observed that pyriproxyfen and B. thuringiensis effect the antioxidant defence system of G. mellonella larvae even if at low doses. If this kind of insecticides were applied at sublethal doses, economical, biological and ecological benefits were achieved as well.
تأثير منظمي النمو Match و Nomolt درس عمى البروتينات الكمية وأنزيم)Aspartate transaminase (AST للأطوار المختمفة لمصرصر الألماني B. germanica وقد أظيرت نتائج د ارسة تأثير منظمي النمو Match و Nomolt عمى البروتينات الكمية للأطوار المختمفة معنوية الفروقات (0.05<p) بين منظمي النمو وكذلك مع مجموعة السيطرة إذ تبين أن معدل تأثير منظمي النمو عمى بروتينات الأطوار الحورية المبكرة لمحشرة كان أعمى من تأثير المنظمين عمى بروتينات الأطوار المتأخرة والحشرة الكاممة . في حين أظيرت نتائج د ارسة تأثير منظمي النمو Match و Nomolt عمى فعالية أنزيم )Aspartate transaminase (AST للأطوار المختمفة أن منظمي النمو ليا تأثير واضح عمى نشاط الأنزيم وأدى إلى أختلاف فعالية الأنزيم ، إذ إن ىذا التأثير كان معنويًا وكان متوسط تأثير منظم النمو Match ىو 0.70±3.21 ومتوسط تأثير منظم النمو Nomolt ىو 0.40±3.76 وأظيرت النتائج فروقات معنوية بين متوسطي فعالية الأنزيم عمى الأطوار المختمفة لمحشرة وكذلك بين كل من متوسطي الأنزيم في المعاممة بالمنظمين
وبين مجموعة السيطرة إذ كان متوسط فعالية الأنزيم في مجموعة السيطرة ىو 0.55±4.71 .
The pink bollworm, Pectinophora gossypiella, is a dangerous pest of cotton worldwide, The objective of the current study was to evaluate the disruptive effects of the chitin synthesis inhibitors, noviflumuron and novaluron, on the adult performance and reproductive potential of this pest after treatment of 1-day old eggs with sublethal concentrations of noviflumuron (4.0, 2.0, 1.0 and 0.5 ppm) and novaluron (1.0, 0.5, 0.1 and 0.05 ppm). The adult emergence was considerably blocked by both compounds but they failed to affect the adult survival or morphogenesis. The total adult longevity was remarkably shortened. Noviflumuron treatment caused a slight prolongation or shortening of pre-oviposition period, depending on the concentration but novaluron treatment led to slightly prolonged period. The oviposition period was remarkably shortened. Prolonged post-oviposition period was recorded by both compounds. The oviposition efficiency was significantly prohibited, regardless the tested compound. Fecundity of the successfully reproducing females and fertility of eggs laid by these females were drastically reduced. The incubation period of eggs was considerably prolonged by both compounds.
1 Chlorfluazuron and hydroprene expressed as (%) and hexaflumuron expressed as µg /ml.. Means withen columns followed by the same letter are not significantly different (Tukeys test
- +0 1+
0+0.1+0.1 Chlorfluazuron and hydroprene expressed as (%) and hexaflumuron expressed as µg /ml.. Means withen columns followed by the same letter are not significantly different (Tukeys test, P≤ 0.05).