The morphology of antennal sensilla of both nymphs and adults in the cicada Meimuna mongolica (Distant) were studied. Four instars of M. mongolica (Distant) were preliminarily determined using Dyar's rule and a r...The morphology of antennal sensilla of both nymphs and adults in the cicada Meimuna mongolica (Distant) were studied. Four instars of M. mongolica (Distant) were preliminarily determined using Dyar's rule and a regression analysis of the head width of nymphs, combined with the comparative morphology of antennae of different stage nymphs and adults. The antennae of nymphs in different instars and adults show great morphological variations. The numbers, types and distribution of antennal sensilla in nymphs and adults of M. mongolica are significantly different, which should be closely related to the niche changes of the nymphs and adults, and provide implications for the development stages of this cicada.展开更多
The artemisia weevil, Adosomus sp., has become an important wormwood (Artemisa ordosoca and A. sphaerocephala) pest in recent years in Ningxia Province, China. The number of larval instars should be determined befor...The artemisia weevil, Adosomus sp., has become an important wormwood (Artemisa ordosoca and A. sphaerocephala) pest in recent years in Ningxia Province, China. The number of larval instars should be determined before further studies on its life history, biology and integrate management of pest (IMP). In this study, we measured the length and width of head capsule, based on frequency histograms and Dyar's law, from which we concluded that the larvae ofAdosomus sp. have four instars. Of the two variables measured, the width of head capsule provided the best division of instars. The average width of head capsule of the 1st instar larvae was 1.348±0.152 mm, the 2nd 2.109±0.199 mm, the 3rd 3.563±0.492 mm and the 4th 5.974±0.581 mm.展开更多
The current experiment was conducted to find out the optimal conditions for mass rearing and developmental changes of Cyclosainsulana. The lab. conditions were maintained at (27±2)℃ and (65±5)% RH. The ...The current experiment was conducted to find out the optimal conditions for mass rearing and developmental changes of Cyclosainsulana. The lab. conditions were maintained at (27±2)℃ and (65±5)% RH. The clear perplex cages and natural diet consisting of the aphids, larvae of the house fly and larvae of drosophila were used for rearing. C. insulana took (123.12±7.26) days to develop from eggs to adults passing through eight instars under prevailing vivo conditions. The eggs were greenish white in color with average size of 0.57 mm ±0.034. The eggs spent (7.52±1.64) days in emergence. Maximum number of spiderlings survived at the 5th instar (84%) and minimum at the 1st instar (34%). The measurements of different body parts including the total body length, cephalothorax and pedipalps of the both male and female C. insulana were done with the help of micrometer and presented as mean± SD. The measurements varied in the each developing instar. It was concluded that spiders were difficult to rear in the lab. conditions and each developing stage which was regarded as instars showed variations in size colors and body characteristics.展开更多
Apriona germari larvae were obtained via sample collection in woodland and indoor rearing. In this study, larval instars were divided by Dyar's law, and the results showed that the larval stage of A. germari comprise...Apriona germari larvae were obtained via sample collection in woodland and indoor rearing. In this study, larval instars were divided by Dyar's law, and the results showed that the larval stage of A. germari comprised six instars, while the width of head capsule was the best instar-dividing structure. On the basis of instar division, tubercle numbers on the transverse furrow downside of first abdominal dorsal ambulatory ampullae, seta numbers of abdominal telson and lateral seta numbers of mandible were observed and statistically calculated. The accuracy of instar-dividing was verified by comparing with the Dyar's law. The coincidence rate of two instar-dividing results was 90. 47%. It is approved that the above morphological features could be used in instar division ofA. germari larvae.展开更多
[Objectives]The paper was to screen effective biocontrol strains against Meloidogyne incognita.[Methods]The effect of six bacterial strains sourced from the research group s strain library on the activity of second in...[Objectives]The paper was to screen effective biocontrol strains against Meloidogyne incognita.[Methods]The effect of six bacterial strains sourced from the research group s strain library on the activity of second instar larvae of M.incognita,as well as on egg hatching,was evaluated.[Results]The treatment of fermentation supernatant derived from the X-2 strain exhibited a pronounced lethal effect on M.incognita,with a corrected mortality rate reaching 97%within 72 h.Additionally,this treatment significantly inhibited egg hatching,achieving an inhibition rate of 94.69%at a 20-fold dilution.The strain was identified as Bacillus velezensis,belonging to the genus Bacillus,and was designated as RKN1111.[Conclusions]This study presents alternative strains and a theoretical framework for the biological control of M.incognita.展开更多
Parasitization has an enormous impact on host physiology, development and reproduction. The effect of parasitism by endoparasitoid, Aenasius bambawalei Hayat (Hymenoptera: Encyrtidae) on survival and reproduction of m...Parasitization has an enormous impact on host physiology, development and reproduction. The effect of parasitism by endoparasitoid, Aenasius bambawalei Hayat (Hymenoptera: Encyrtidae) on survival and reproduction of mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) on different host stages was studied. Our data reveals that host mealybugs parasitized by the wasp at the 2<sup>nd</sup> instar stage were died during the 3<sup>rd</sup> instar stage of their life. However, those parasitized at the 3<sup>rd</sup> instar stage could reach the adult stage and were able to produce their progeny. After 6 days of parasitization, all parasitized hosts of the 2<sup>nd</sup>, 3<sup>rd</sup> and adult stages were died except the 1<sup>st</sup> instar. Results showed that parasitized host mealybugs had significantly lower reproductive potential than the unparasitized ones. Maximum parasitoid emergence was recorded in the 3<sup>rd</sup> instar host stage. This basic research regarding survival and reproduction of the parasitized host mealybugs would be very helpful in devising sustainable biological control strategies for cotton mealybug.展开更多
Micromelalopha troglodyta (Graeser) is an important pest of poplar in China. Glutathione S-transferases (GSTs) are known to be responsible for adaptation mechanisms of M. troglodyta. The activities and kinetic con...Micromelalopha troglodyta (Graeser) is an important pest of poplar in China. Glutathione S-transferases (GSTs) are known to be responsible for adaptation mechanisms of M. troglodyta. The activities and kinetic constants of glutathione S-transferases in M. troglodyta were studied. Significant differences in glutathione S-transferase activity and kinetic characteristics were observed among five instars of M. troglodyta larvae. Furthermore, the inhibition of glutathione S-transferase activity in five instars by 24 inhibitors was conducted. The results show the inhibition of GST activity of different instars by 24 inhibitors was different. For GST activity in the 1st instar, chlorpyrifos, lambda-cyhalothrin, endosulfan, abamectin, fipronil and pyridaben were the best inhibitors tested, and for GST activity in the 2nd instar, tannic acid and quercetin were the most potent inhibitors tested, and for GST activity in the 3rd instar, the inhibitory effects of quercetin, chlorpyrifos and lambda-cyhalothrin were the highest, and for GST activity in the 4th instar, quercetin and lambda-cyhalothrin were the best inhibitors, and the inhibitory effect of phoxim was the highest for GST activity in the 5th instar. Our results show that glutathione S-transferases in different instars are qualitatively different in isozyme composition and thus different in sensitivity to inhibitors.展开更多
The tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is among the most destructive pests that attack tomato in many countries. In this study, the efficiency of three suspensions (106;105;104 cell/...The tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is among the most destructive pests that attack tomato in many countries. In this study, the efficiency of three suspensions (106;105;104 cell/ml) of Bacillus thuringiensis var. Kurstaki was tested on T. absoluta larvae 1st, 2nd, 3rd and 4th instar was assessed to study the effect of these suspensions on larval mortality. Results showed that the concentration 106 cell/ml resulted in the highest mortality of all instars larvae with an average mortality of 20%, 22.66%, 18.66% and 23.33% was recorded for the first, second, third and fourth instar, respectively. The greatest percentage of mortality occurred in the third day after the larvae fed with leaves treated with suspension B. thuringiensis.展开更多
The critical antioxidant catalase(CAT)breaks down hydrogen peroxide induced by environmental stresses.Here we cloned full length catalase cDNA from Lymantria dispar asiatic(LdCAT).Bioinformatic analyses showed that op...The critical antioxidant catalase(CAT)breaks down hydrogen peroxide induced by environmental stresses.Here we cloned full length catalase cDNA from Lymantria dispar asiatic(LdCAT).Bioinformatic analyses showed that open reading frames of LdCAT contains 1524 bp,encoding 507 amino acids with molecular weight of 126.99 kDa,theoretical pI of 5.00,aliphatic index of 29.92,grand average of hydropathicity of 0.764,and instability index(II)of 46.56.Protein BLAST and multiple sequence alignment indicated that LdCAT had high identity with CAT from other insects,especially lepidopterans.In a phylogenetic analysis,LdCAT was most similar to CAT from Spodoptera litura and S.exigua.Quantitative realtime polymerase chain reaction showed that LdCAT transcripts in all instar larvae and the five tissues tested,verifying the ubiquity of LdCAT in L.disapr.Moreover,LdCAT of third instar larvae was significantly upregulated after they fed on avermectin at sublethal and LC10 doses.The highest relative transcript levels were found 2 h after an avermectin spray at LC90,and in the cuticula,rather than heads,fat bodies,malpighian tubes,and midguts after a spray avermectin at a sublethal concentration.The expression level of LdCAT under pesticide stresses here suggested that CAT is an important antioxidant enzyme of L.disapr defensing against pesticide stress and may be a good target for controlling this pest.展开更多
Objective:To evaluate the effectiveness and residual effects of trypsin modulating ecstatic factor-Bacillus thuringiensis israeliensis(TMOF-Bti) formulations against Aedes aegypti(Ae. aegypti)(L) larvae at UKM Campus ...Objective:To evaluate the effectiveness and residual effects of trypsin modulating ecstatic factor-Bacillus thuringiensis israeliensis(TMOF-Bti) formulations against Aedes aegypti(Ae. aegypti)(L) larvae at UKM Campus Kuala Lumpur.Methods:Twenty first instar Ae.aegypti larvae were added in each bucket containing 4 L of water supplied with crushed dried-leaf powder as their source of food.Combination of TMOF-Bti in rice husk formulation with the following weights viz 10,25,50 and 100 mg,respectively in duplicate was distributed in the buckets;while TMOF-Bti in wettable powder formulation each weighing viz 2,5,10 and 20 mg,respectively in duplicate was also placed in the buckets.The control buckets run in duplicate with 4 L of water and 20 first instar Ae.aegypti larvae.All buckets were covered with mosquito netting.Larval mortality was recorded after 24 hours and weekly for five weeks.A new batch of 20 1^(st) instar larvae Ae.aegypti was introduced into each bucket weekly without additional TMOF-Bti rice husk formulation or wettable powder.The experiment was repeated for four times.Results:The result of the study showed that all formulations were very effective on the first two weeks by giving 100% larval mortality for all concentrations applied.The TMOF(2%) + Bti(2%) had a good residual effect until the end of 3^(rd) week,TMOF(4%) + Bti(4%) until 4^(th) week,wettable powder TMOF(20%) + Bti(20%) until the third week.Condusions:From the results it can be concluded that the TMOF-Bti formulations can be utilized in dengue vector control.展开更多
Dilaridae are a distinctive and phylogenetically ambiguous neuropteran family.So far,the anatomy of the immature stages remains largely unknown.We examined the 1st instar larvae of Dilar montanus in detail and present...Dilaridae are a distinctive and phylogenetically ambiguous neuropteran family.So far,the anatomy of the immature stages remains largely unknown.We examined the 1st instar larvae of Dilar montanus in detail and present results of live observations for the first time.The minute,cryptic larvae display features correlated with their underground lifestyle:for instance,a strongly flattened head,stout antennae,eyelessness,and burrowing forelegs.In contrast to molecular data,several characters suggest a‘dilarid clade’combining Dilaridae with Mantispoidea,for instance a very thin and curved or reduced tentorial bridge,and an elongated postmentum.We found intrinsic antennal muscles and Johnston's organ,the first record of these structures in holometabolous larvae.This proves that the first 2 larval antennomeres are homologous with the scapus and pedicellus.The described characters are discussed and analyzed with an updated matrix of neuropteran larval characters.Alternative scenarios of character evolution are presented.Additionally,we show how the 1st-instar larvae move and feed in the substrate,and also provide a high-resolution video recording of the function of the elongate tubular ovipositor and the egg-laying behavior in an adult female under natural conditions.展开更多
The polyphagous shot hole borer (PSHB), Euwallacea sp., was first detected in 2003 in Los Angeles County, California, USA. Recently, this invasive species has become a major pest of many hardwood trees in urban and ...The polyphagous shot hole borer (PSHB), Euwallacea sp., was first detected in 2003 in Los Angeles County, California, USA. Recently, this invasive species has become a major pest of many hardwood trees in urban and wildland forests throughout southern California. PSHB is nearly identical in morphology and life history to the tea shot hole borer (TSHB), Euwallaceafornicatus, an invasive pest of hardwoods in Florida, USA and many other parts of the world. However, molecular studies have suggested that the taxa are different species. We conducted morphometric and chemical analyses of the pheno- types of Euwallacea sp. collected in southern California (Los Angeles County) and E. fornicatus collected in Florida (Miami-Dade County). Our analyses indicated that PSHB has 3 larval instars. The third larval instar was separated from the first 2 instars by head capsule width with 0 probability of misclassification. The body length, head width, and pronotal width of PSHB adult males were significantly less than those of females. Head width and pronotal width of female PSHB were significantly less than those of female TSHB. In contrast, body length, and ratio of body length to pronotal width of female PSHB were significantly greater than those of female TSHB. However, females of these 2 species could not be separated completely by these 4 measurements because of the overlapping ranges. Cuticular hydrocarbons detected in both species were exclusively alkanes (i.e., n-alkanes, monomethylalkanes, dimethylalkanes, and trimethylalkanes). Cuticular hydro- carbon profiles of PSHB males and females were similar, but they both differed from that of TSHB females. Cuticular hydrocarbons of PSHB were predominantly internally branched dimethylalkanes with backbones of 31 and 33 carbons, whereas cuticular hydro- carbons of TSHB females were dominated by internally branched monomethylalkanes and dimethylalkanes with backbones of 28 and 29 carbons. Multiple compounds within these classes appear to be diagnostic for PSHB and TSHB, respectively.展开更多
Triatominae species are considered the main vectors of Chagas disease or American Trypanosomiasis. In Venezuela, the principal vectors are Rhodnius prolixus (Stal, 1959) and Triatoma maculata (Erichson, 1848), whi...Triatominae species are considered the main vectors of Chagas disease or American Trypanosomiasis. In Venezuela, the principal vectors are Rhodnius prolixus (Stal, 1959) and Triatoma maculata (Erichson, 1848), which are belonged to the tribe Rhodniini and Triatomini, respectively. The head conformation and size development of these species can reflect ontogenetic changes which contribute with the vectors biology studies, as well to support of instars determination. The goal of the paper is to the application of geometric morphometric techniques for describing head conformation and size of instars of these species. We photographed 140 heads in R. prolixus: First instar (I: 16), second instar (II: 17), third instar (III: 18), fourth instar (IV: 21), fifth instar (V: 21), adult female (F: 26) and adult males (M: 21); in T. maculata heads of 136 specimens were photographed,I: 20, II: 17, III: 26, IV: 15, V: 19, F: 20 and M: 19. Landmark coordinate (x, y) configurations were registered and aligned by Generalized Procrustes Analysis. Covariance Analyses were implemented with proportions of re-classified groups and MANOVA. Statistical analyses of variance found not significant differences in head isometric size (Kruskal-Wallis) among IV and V instars in both species. The a posteriori re-classification was almost perfect in R. prolixus (82%) and T. maculata (86%); the main head differences occurs in antenniferous tubercles, postocular and preocular. Our study using quantitative tools for describing the shape differences contributes to explain the morphology variability and development of Chagas disease vectors.展开更多
The yellow peach moth, Conogethes punctiferalis (Guenee), a multivoltine species that overwinters as diapausing larvae, is one of the most serious insect pests on maize in China. Effect of photoperiod and temperatur...The yellow peach moth, Conogethes punctiferalis (Guenee), a multivoltine species that overwinters as diapausing larvae, is one of the most serious insect pests on maize in China. Effect of photoperiod and temperature on larval diapause was examined under empirical laboratory conditions. Short-day treatments caused larval diapause at 25℃, and the critical photoperiod was between 12 and 13 h (or 12 h 51 min) light per day. No sensitive instar was identified for diapause induction under alternated short- (L : D 11 : 13 h) and long-day (L : D 14 : 10 h) treatments at different larval stages. However, accumulative treatment of three instars and 10 d under short-day treatment was required for the induction of 50% larval diapause. All larvae entered diapause at 20℃, whereas less than 3% did so at 30℃, irrespective of the long- or short-day treatment. Furthermore, under the short-day treatment, more than 90% of larvae went into diapause with temperatures ≤ 25℃, but less than 17% did so at 28℃. In contrast, under the long-day treatment, less than 19% of larvae went into diapause with temperatures ≥23 ℃. The forward shift (5℃) of critical temperature under the long-day regime demonstrated the compensatory effect of temperature and photoperiod on diapause induction. In conclusion, C. punctiferalis had a temperature-dependent type Ⅰ photoperiodic diapause response; there was no sensitive instar for diapause determination, but the photoperiodic accumulation time countermeasures both of the short-day cycles and the number ofinstars exposed, and the photoperiodic diapause response, was a temperature-compensated phenomenon.展开更多
Polyphenol oxidase (PPO) is the enzyme responsible for enzymatic browning during the growth of insects. It is also involved in defense reactions and is related with immunities in insects. PPO a metalloenzyme oxidase...Polyphenol oxidase (PPO) is the enzyme responsible for enzymatic browning during the growth of insects. It is also involved in defense reactions and is related with immunities in insects. PPO a metalloenzyme oxidase, catalyzes the oxidation of o-diphenol to o-quinone. The present paper describes the effects of benzaldehyde and its p-substituted derivatives on the activity of PPO from the fifth instar of Pieris rapae L. PPO from the fifth instar of Pieris rapae L. was purified using ammonium sulfate fractionation and chromatography on Sephadex G-100. The enzyme kinetics was characterized using L-3,4-dihydroxyphenylalanine (L-DOPA) as substrate. The results show that benzaldehyde, phydroxybenzaldehyde, p-chlorobenzaldehyde, and p-cyanobenzaldehyde can inhibit the PPO activity for the oxidation of L-DOPA. The inhibitor concentration leading to 50% activity lost, IC50, was estimated to be 5.90, 5.62, 2.83, and 2.91 mmol/L for the four tested inhibitors, respectively. Kinetic analyses show that the inhibitory effects of these compounds are reversible. Benzaldehyde, phydroxybenzaldehyde, and p-chlorobenzaldehyde are noncompetitive inhibitors while p-cyanobenzaldehyde is a mixed-type inhibitor. The inhibition constants were determined for all four inhibitors. p-chlorobenzaldehyde and p-cyanobenzaldehyde were more potent inhibitors than the other compounds. These results provide a basis for developing PPO inhibition-based pesticides.展开更多
基金supported by the National Natural Science Foundation of China (31093430)the Program for New Century Excellent Talents in Universities of China (NCET-10-0691)
文摘The morphology of antennal sensilla of both nymphs and adults in the cicada Meimuna mongolica (Distant) were studied. Four instars of M. mongolica (Distant) were preliminarily determined using Dyar's rule and a regression analysis of the head width of nymphs, combined with the comparative morphology of antennae of different stage nymphs and adults. The antennae of nymphs in different instars and adults show great morphological variations. The numbers, types and distribution of antennal sensilla in nymphs and adults of M. mongolica are significantly different, which should be closely related to the niche changes of the nymphs and adults, and provide implications for the development stages of this cicada.
基金supported by the National Project of ScienceTechnology for the 11th Five-Year Plan in China (Grant No. 2006BADO8A12)
文摘The artemisia weevil, Adosomus sp., has become an important wormwood (Artemisa ordosoca and A. sphaerocephala) pest in recent years in Ningxia Province, China. The number of larval instars should be determined before further studies on its life history, biology and integrate management of pest (IMP). In this study, we measured the length and width of head capsule, based on frequency histograms and Dyar's law, from which we concluded that the larvae ofAdosomus sp. have four instars. Of the two variables measured, the width of head capsule provided the best division of instars. The average width of head capsule of the 1st instar larvae was 1.348±0.152 mm, the 2nd 2.109±0.199 mm, the 3rd 3.563±0.492 mm and the 4th 5.974±0.581 mm.
文摘The current experiment was conducted to find out the optimal conditions for mass rearing and developmental changes of Cyclosainsulana. The lab. conditions were maintained at (27±2)℃ and (65±5)% RH. The clear perplex cages and natural diet consisting of the aphids, larvae of the house fly and larvae of drosophila were used for rearing. C. insulana took (123.12±7.26) days to develop from eggs to adults passing through eight instars under prevailing vivo conditions. The eggs were greenish white in color with average size of 0.57 mm ±0.034. The eggs spent (7.52±1.64) days in emergence. Maximum number of spiderlings survived at the 5th instar (84%) and minimum at the 1st instar (34%). The measurements of different body parts including the total body length, cephalothorax and pedipalps of the both male and female C. insulana were done with the help of micrometer and presented as mean± SD. The measurements varied in the each developing instar. It was concluded that spiders were difficult to rear in the lab. conditions and each developing stage which was regarded as instars showed variations in size colors and body characteristics.
基金Supported by Innovation Project of Graduate Education of Jiangsu Province(CXZZ11_0538)Project of Nanjing Construction Committee and the Administration Bureau of Dr.Sun Yat-sen's Mausoleum(200409)
文摘Apriona germari larvae were obtained via sample collection in woodland and indoor rearing. In this study, larval instars were divided by Dyar's law, and the results showed that the larval stage of A. germari comprised six instars, while the width of head capsule was the best instar-dividing structure. On the basis of instar division, tubercle numbers on the transverse furrow downside of first abdominal dorsal ambulatory ampullae, seta numbers of abdominal telson and lateral seta numbers of mandible were observed and statistically calculated. The accuracy of instar-dividing was verified by comparing with the Dyar's law. The coincidence rate of two instar-dividing results was 90. 47%. It is approved that the above morphological features could be used in instar division ofA. germari larvae.
基金Supported by Key R&D Project of Science&Technology Department of Ningxia Hui Autonomous Region(2021BBF02013)Post-doctoral Program of Hebei Province(2019003011)Hebei Province Innovation Ability Enhancement Plan Project(225676109H).
文摘[Objectives]The paper was to screen effective biocontrol strains against Meloidogyne incognita.[Methods]The effect of six bacterial strains sourced from the research group s strain library on the activity of second instar larvae of M.incognita,as well as on egg hatching,was evaluated.[Results]The treatment of fermentation supernatant derived from the X-2 strain exhibited a pronounced lethal effect on M.incognita,with a corrected mortality rate reaching 97%within 72 h.Additionally,this treatment significantly inhibited egg hatching,achieving an inhibition rate of 94.69%at a 20-fold dilution.The strain was identified as Bacillus velezensis,belonging to the genus Bacillus,and was designated as RKN1111.[Conclusions]This study presents alternative strains and a theoretical framework for the biological control of M.incognita.
文摘Parasitization has an enormous impact on host physiology, development and reproduction. The effect of parasitism by endoparasitoid, Aenasius bambawalei Hayat (Hymenoptera: Encyrtidae) on survival and reproduction of mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) on different host stages was studied. Our data reveals that host mealybugs parasitized by the wasp at the 2<sup>nd</sup> instar stage were died during the 3<sup>rd</sup> instar stage of their life. However, those parasitized at the 3<sup>rd</sup> instar stage could reach the adult stage and were able to produce their progeny. After 6 days of parasitization, all parasitized hosts of the 2<sup>nd</sup>, 3<sup>rd</sup> and adult stages were died except the 1<sup>st</sup> instar. Results showed that parasitized host mealybugs had significantly lower reproductive potential than the unparasitized ones. Maximum parasitoid emergence was recorded in the 3<sup>rd</sup> instar host stage. This basic research regarding survival and reproduction of the parasitized host mealybugs would be very helpful in devising sustainable biological control strategies for cotton mealybug.
基金supported by National Natural Science Foundation of China(Contract No.30600476 and 30972376)
文摘Micromelalopha troglodyta (Graeser) is an important pest of poplar in China. Glutathione S-transferases (GSTs) are known to be responsible for adaptation mechanisms of M. troglodyta. The activities and kinetic constants of glutathione S-transferases in M. troglodyta were studied. Significant differences in glutathione S-transferase activity and kinetic characteristics were observed among five instars of M. troglodyta larvae. Furthermore, the inhibition of glutathione S-transferase activity in five instars by 24 inhibitors was conducted. The results show the inhibition of GST activity of different instars by 24 inhibitors was different. For GST activity in the 1st instar, chlorpyrifos, lambda-cyhalothrin, endosulfan, abamectin, fipronil and pyridaben were the best inhibitors tested, and for GST activity in the 2nd instar, tannic acid and quercetin were the most potent inhibitors tested, and for GST activity in the 3rd instar, the inhibitory effects of quercetin, chlorpyrifos and lambda-cyhalothrin were the highest, and for GST activity in the 4th instar, quercetin and lambda-cyhalothrin were the best inhibitors, and the inhibitory effect of phoxim was the highest for GST activity in the 5th instar. Our results show that glutathione S-transferases in different instars are qualitatively different in isozyme composition and thus different in sensitivity to inhibitors.
文摘The tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is among the most destructive pests that attack tomato in many countries. In this study, the efficiency of three suspensions (106;105;104 cell/ml) of Bacillus thuringiensis var. Kurstaki was tested on T. absoluta larvae 1st, 2nd, 3rd and 4th instar was assessed to study the effect of these suspensions on larval mortality. Results showed that the concentration 106 cell/ml resulted in the highest mortality of all instars larvae with an average mortality of 20%, 22.66%, 18.66% and 23.33% was recorded for the first, second, third and fourth instar, respectively. The greatest percentage of mortality occurred in the third day after the larvae fed with leaves treated with suspension B. thuringiensis.
文摘The critical antioxidant catalase(CAT)breaks down hydrogen peroxide induced by environmental stresses.Here we cloned full length catalase cDNA from Lymantria dispar asiatic(LdCAT).Bioinformatic analyses showed that open reading frames of LdCAT contains 1524 bp,encoding 507 amino acids with molecular weight of 126.99 kDa,theoretical pI of 5.00,aliphatic index of 29.92,grand average of hydropathicity of 0.764,and instability index(II)of 46.56.Protein BLAST and multiple sequence alignment indicated that LdCAT had high identity with CAT from other insects,especially lepidopterans.In a phylogenetic analysis,LdCAT was most similar to CAT from Spodoptera litura and S.exigua.Quantitative realtime polymerase chain reaction showed that LdCAT transcripts in all instar larvae and the five tissues tested,verifying the ubiquity of LdCAT in L.disapr.Moreover,LdCAT of third instar larvae was significantly upregulated after they fed on avermectin at sublethal and LC10 doses.The highest relative transcript levels were found 2 h after an avermectin spray at LC90,and in the cuticula,rather than heads,fat bodies,malpighian tubes,and midguts after a spray avermectin at a sublethal concentration.The expression level of LdCAT under pesticide stresses here suggested that CAT is an important antioxidant enzyme of L.disapr defensing against pesticide stress and may be a good target for controlling this pest.
基金financially supported by Entogenex Industries Sdn.Bhd.,Malaysia(grant No.NN 001-2008)
文摘Objective:To evaluate the effectiveness and residual effects of trypsin modulating ecstatic factor-Bacillus thuringiensis israeliensis(TMOF-Bti) formulations against Aedes aegypti(Ae. aegypti)(L) larvae at UKM Campus Kuala Lumpur.Methods:Twenty first instar Ae.aegypti larvae were added in each bucket containing 4 L of water supplied with crushed dried-leaf powder as their source of food.Combination of TMOF-Bti in rice husk formulation with the following weights viz 10,25,50 and 100 mg,respectively in duplicate was distributed in the buckets;while TMOF-Bti in wettable powder formulation each weighing viz 2,5,10 and 20 mg,respectively in duplicate was also placed in the buckets.The control buckets run in duplicate with 4 L of water and 20 first instar Ae.aegypti larvae.All buckets were covered with mosquito netting.Larval mortality was recorded after 24 hours and weekly for five weeks.A new batch of 20 1^(st) instar larvae Ae.aegypti was introduced into each bucket weekly without additional TMOF-Bti rice husk formulation or wettable powder.The experiment was repeated for four times.Results:The result of the study showed that all formulations were very effective on the first two weeks by giving 100% larval mortality for all concentrations applied.The TMOF(2%) + Bti(2%) had a good residual effect until the end of 3^(rd) week,TMOF(4%) + Bti(4%) until 4^(th) week,wettable powder TMOF(20%) + Bti(20%) until the third week.Condusions:From the results it can be concluded that the TMOF-Bti formulations can be utilized in dengue vector control.
基金supported by the National Natural Science Foundation of China(32130012,31972871)the 2115 Talent Development Program of China Agricultural University,the Biodiversity Survey and Assessment Project of the Ministry of Ecology and Environment,China(2019HJ2096001006)the China Scholarship Council for the financial support of Di Li's study at FSU.
文摘Dilaridae are a distinctive and phylogenetically ambiguous neuropteran family.So far,the anatomy of the immature stages remains largely unknown.We examined the 1st instar larvae of Dilar montanus in detail and present results of live observations for the first time.The minute,cryptic larvae display features correlated with their underground lifestyle:for instance,a strongly flattened head,stout antennae,eyelessness,and burrowing forelegs.In contrast to molecular data,several characters suggest a‘dilarid clade’combining Dilaridae with Mantispoidea,for instance a very thin and curved or reduced tentorial bridge,and an elongated postmentum.We found intrinsic antennal muscles and Johnston's organ,the first record of these structures in holometabolous larvae.This proves that the first 2 larval antennomeres are homologous with the scapus and pedicellus.The described characters are discussed and analyzed with an updated matrix of neuropteran larval characters.Alternative scenarios of character evolution are presented.Additionally,we show how the 1st-instar larvae move and feed in the substrate,and also provide a high-resolution video recording of the function of the elongate tubular ovipositor and the egg-laying behavior in an adult female under natural conditions.
文摘The polyphagous shot hole borer (PSHB), Euwallacea sp., was first detected in 2003 in Los Angeles County, California, USA. Recently, this invasive species has become a major pest of many hardwood trees in urban and wildland forests throughout southern California. PSHB is nearly identical in morphology and life history to the tea shot hole borer (TSHB), Euwallaceafornicatus, an invasive pest of hardwoods in Florida, USA and many other parts of the world. However, molecular studies have suggested that the taxa are different species. We conducted morphometric and chemical analyses of the pheno- types of Euwallacea sp. collected in southern California (Los Angeles County) and E. fornicatus collected in Florida (Miami-Dade County). Our analyses indicated that PSHB has 3 larval instars. The third larval instar was separated from the first 2 instars by head capsule width with 0 probability of misclassification. The body length, head width, and pronotal width of PSHB adult males were significantly less than those of females. Head width and pronotal width of female PSHB were significantly less than those of female TSHB. In contrast, body length, and ratio of body length to pronotal width of female PSHB were significantly greater than those of female TSHB. However, females of these 2 species could not be separated completely by these 4 measurements because of the overlapping ranges. Cuticular hydrocarbons detected in both species were exclusively alkanes (i.e., n-alkanes, monomethylalkanes, dimethylalkanes, and trimethylalkanes). Cuticular hydro- carbon profiles of PSHB males and females were similar, but they both differed from that of TSHB females. Cuticular hydrocarbons of PSHB were predominantly internally branched dimethylalkanes with backbones of 31 and 33 carbons, whereas cuticular hydro- carbons of TSHB females were dominated by internally branched monomethylalkanes and dimethylalkanes with backbones of 28 and 29 carbons. Multiple compounds within these classes appear to be diagnostic for PSHB and TSHB, respectively.
基金supported by the Servicio Autónomo Instituto de Altos Estudios en Salud Pública “Dr:Arnoldo Gabaldon” (IAES) Aragua,Venezuela
文摘Triatominae species are considered the main vectors of Chagas disease or American Trypanosomiasis. In Venezuela, the principal vectors are Rhodnius prolixus (Stal, 1959) and Triatoma maculata (Erichson, 1848), which are belonged to the tribe Rhodniini and Triatomini, respectively. The head conformation and size development of these species can reflect ontogenetic changes which contribute with the vectors biology studies, as well to support of instars determination. The goal of the paper is to the application of geometric morphometric techniques for describing head conformation and size of instars of these species. We photographed 140 heads in R. prolixus: First instar (I: 16), second instar (II: 17), third instar (III: 18), fourth instar (IV: 21), fifth instar (V: 21), adult female (F: 26) and adult males (M: 21); in T. maculata heads of 136 specimens were photographed,I: 20, II: 17, III: 26, IV: 15, V: 19, F: 20 and M: 19. Landmark coordinate (x, y) configurations were registered and aligned by Generalized Procrustes Analysis. Covariance Analyses were implemented with proportions of re-classified groups and MANOVA. Statistical analyses of variance found not significant differences in head isometric size (Kruskal-Wallis) among IV and V instars in both species. The a posteriori re-classification was almost perfect in R. prolixus (82%) and T. maculata (86%); the main head differences occurs in antenniferous tubercles, postocular and preocular. Our study using quantitative tools for describing the shape differences contributes to explain the morphology variability and development of Chagas disease vectors.
文摘The yellow peach moth, Conogethes punctiferalis (Guenee), a multivoltine species that overwinters as diapausing larvae, is one of the most serious insect pests on maize in China. Effect of photoperiod and temperature on larval diapause was examined under empirical laboratory conditions. Short-day treatments caused larval diapause at 25℃, and the critical photoperiod was between 12 and 13 h (or 12 h 51 min) light per day. No sensitive instar was identified for diapause induction under alternated short- (L : D 11 : 13 h) and long-day (L : D 14 : 10 h) treatments at different larval stages. However, accumulative treatment of three instars and 10 d under short-day treatment was required for the induction of 50% larval diapause. All larvae entered diapause at 20℃, whereas less than 3% did so at 30℃, irrespective of the long- or short-day treatment. Furthermore, under the short-day treatment, more than 90% of larvae went into diapause with temperatures ≤ 25℃, but less than 17% did so at 28℃. In contrast, under the long-day treatment, less than 19% of larvae went into diapause with temperatures ≥23 ℃. The forward shift (5℃) of critical temperature under the long-day regime demonstrated the compensatory effect of temperature and photoperiod on diapause induction. In conclusion, C. punctiferalis had a temperature-dependent type Ⅰ photoperiodic diapause response; there was no sensitive instar for diapause determination, but the photoperiodic accumulation time countermeasures both of the short-day cycles and the number ofinstars exposed, and the photoperiodic diapause response, was a temperature-compensated phenomenon.
基金Supported by the Science and Technology Foundation of Fujian Province (No. 2004N002)the National Natural Science Foundation of China (No. 30570408)
文摘Polyphenol oxidase (PPO) is the enzyme responsible for enzymatic browning during the growth of insects. It is also involved in defense reactions and is related with immunities in insects. PPO a metalloenzyme oxidase, catalyzes the oxidation of o-diphenol to o-quinone. The present paper describes the effects of benzaldehyde and its p-substituted derivatives on the activity of PPO from the fifth instar of Pieris rapae L. PPO from the fifth instar of Pieris rapae L. was purified using ammonium sulfate fractionation and chromatography on Sephadex G-100. The enzyme kinetics was characterized using L-3,4-dihydroxyphenylalanine (L-DOPA) as substrate. The results show that benzaldehyde, phydroxybenzaldehyde, p-chlorobenzaldehyde, and p-cyanobenzaldehyde can inhibit the PPO activity for the oxidation of L-DOPA. The inhibitor concentration leading to 50% activity lost, IC50, was estimated to be 5.90, 5.62, 2.83, and 2.91 mmol/L for the four tested inhibitors, respectively. Kinetic analyses show that the inhibitory effects of these compounds are reversible. Benzaldehyde, phydroxybenzaldehyde, and p-chlorobenzaldehyde are noncompetitive inhibitors while p-cyanobenzaldehyde is a mixed-type inhibitor. The inhibition constants were determined for all four inhibitors. p-chlorobenzaldehyde and p-cyanobenzaldehyde were more potent inhibitors than the other compounds. These results provide a basis for developing PPO inhibition-based pesticides.