Host-plant volatiles play an important role as cues for herbivores in search of resources, mates and oviposition sites in complex environments. Plant volatile-based attractants can be developed for pest monitoring and...Host-plant volatiles play an important role as cues for herbivores in search of resources, mates and oviposition sites in complex environments. Plant volatile-based attractants can be developed for pest monitoring and control. Previously, we indicated that mated female adults of Callosobruchus chinensis showed choice preference behavior toward 2-hexenal and benzaldehyde. Our objective here was to investigate the synergistic effect of host-derived attractive volatiles in attracting C. chinensis under laboratory and field conditions in Shanxi Province, China. We hypothesized that the ratio and concentration of volatiles derived from Vigna radiata play critical roles for C. chinensis in locating this host. Therefore, we collected and identified the volatiles of mungbean by using headspace collection and GC-MS. The effectiveness of different ratios and concentrations of two compounds (2-hexenal and benzaldehyde) that elicit C. chinensis searching behavior were examined in Y-tube olfactometer assays. The combination of 300 μg μL^–1 2-hexenal and 180 μg μL^–1 benzaldehyde loadings exhibited a synergistic effect on attracting C. chinensis (82.35%). Compared to control traps, the adults were significantly attracted to traps baited with blends, and more attraction to females than males was found for blend traps in the field experiments. Our results suggest that blends of this specific concentration and ratio of benzaldehyde and 2-hexenal can be used in traps as attractants for C. chinensis monitoring and control in the field.展开更多
Turmeric (<i>Curcuma</i><span> <i>longa</i> L</span><span><span><span style="font-family:;" "="">.</span></span></span>&...Turmeric (<i>Curcuma</i><span> <i>longa</i> L</span><span><span><span style="font-family:;" "="">.</span></span></span><span><span><span style="font-family:;" "="">) </span></span></span><span><span><span style="font-family:;" "="">is one of the essential condiments all over the world. Turmeric is an important medicine in the eastern medical systems and its therapeutic properties have been well recorded. Curcumin, commonly called diferuloyl methane (hydrophobic polyphenol), was studied extensively for its biological properties. Sri Lankan turmeric records relatively higher percentage (up to 9%) of curcumin. The bioactive compounds with insecticidal or pesticidal activity w</span></span></span><span><span><span style="font-family:;" "="">ere</span></span></span><span><span><span style="font-family:;" "=""> studied from the Sri Lankan turmeric as there is an increasing demand for natural products to control ticks and fleas in dogs against the chemicals that induce some secondary effects. Fifty grams (50 g) of dried coarsely ground turmeric (<i>Curcuma</i><span> <i>longa</i> L</span></span></span></span><span><span><span style="font-family:;" "="">.</span></span></span><span><span><span style="font-family:;" "="">)</span></span></span><span><span><span style="font-family:;" "=""> was subjected to sequential extractions with four different solvents in ascending order of polarity <span>using Soxhlet apparatus.</span></span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span><span><span style="font-family:;" "="">The treatments consisted of solvent-fractionated tur</span></span></span><span><span><span style="font-family:;" "="">meric extracts from hexane, dichloromethane (CH<sub>2</sub>Cl<sub>2</sub>), ethyl acetate (EtOAc) and Methanol (CH<sub>3</sub>OH) dissolved in the water to 100 ppm. The test carried out using a modified olfactometer and the degree of repellency of common tick species <i>Rhipicephalus</i></span></span></span><span><span><i><span style="font-family:;" "=""> </span></i></span></span><span><span><i><span style="font-family:;" "="">sanguineus</span></i></span></span><span><span><span style="font-family:;" "=""> was recorded. The hexane extract from dried turmeric powder showed the highest repellence of 80% whereas other fractions showed lesser repellence. Further studies in the direction of purification, dose dependent repellency and persistency.</span></span></span>展开更多
Chemosensory systems are considered to play an important role in host plant selection in herbivorous insects.However,few studies have focused on chemosensory proteins(CSPs)for aphid host-location mechanisms.The roles ...Chemosensory systems are considered to play an important role in host plant selection in herbivorous insects.However,few studies have focused on chemosensory proteins(CSPs)for aphid host-location mechanisms.The roles of CSPs in searching for different Poaceae species(wheat,barley,triticale,maize and sorghum)were tested in Rhopalosiphum padi,an important cereal pest.The olfactometer assays showed that R.padi responds to plant odors.Seven R.padi CSP genes were identified.Influence of aphid morph,tissue and starvation state on expression patterns of CSPs was evaluated.Expression levels of CSPI,CSP4,CSP5 and CSP6 in winged aphids were significantly higher than those in wingless ones.Transcription levels of four genes(CSPI,CSP4,CSP5 and CSP6)were relatively higher in the head with antennae,and the four genes tended to be upregulated follow ing starvation.Silencing of three CSPs(CSP4,CSP5 and CSP6)altered aphid host-location behavior in response to the five different host plants tested.Three volatile compounds of host plants(octanal,[E]-2-hexenol and linalool)have signif-icant attraction to winged R.padi according to the four-arm olfactometer tests.Molecular docking predicted hydrogen bonding sites which played key roles in the binding of CSP4,CSP5 and CSP6 with volatile compounds.Knockdown of CSP4 or CSP5 significantly decreased the staying time of R.padi in the arms with octanal.However,knockdown of CSP6 could not affect the response of R.padi to octanal.These results bring evidence for the involvement of three CSPs in R.padi host-location behavior.展开更多
We investigated the responses of 3 thrips species, Frankliniella schultzei Tryborn, E occidentalis Pergrande, and Thrips tabaci Lindeman （Thysanoptera： Thripidae） to herbivore-damaged and undamaged cotton seedlings...We investigated the responses of 3 thrips species, Frankliniella schultzei Tryborn, E occidentalis Pergrande, and Thrips tabaci Lindeman （Thysanoptera： Thripidae） to herbivore-damaged and undamaged cotton seedlings （Gossypium hirsutum L. [Malvales： Malvaceae]） at a range of time intervals following damage by adult Tetranychus urticae （Koch）, adult T. ludeni （Zacher） （Acari： Tetranychidae） or Helicoverpa armigera （Hubner） （Lepidoptera： Noctuidae） larvae in olfactometer assays. The intensity/frequency of the response of thrips to herbivore-induced plants decreased with time and ultimately disappeared in all cases; however, the rate at which the response declined was related to the herbivore species that inflicted the damage. All 3 species of thrips were attracted to plants damaged by T. urticae for longer than they were to plants damaged by T. ludeni. The duration for which damaged plants remained attractive was also affected by the degree of damage inflicted on cotton seedlings. For example, E schultzei was attracted to plants damaged by a higher density of two-spotted spider mites （100/plant） for much longer than to plants damaged by a lower density of these mites （50/plant）. The results reinforce previous studies that demonstrate that arrangement of variables influences the responses of thrips to their herbivore-induced cotton host plants. Results also show that these responses are variable in time following herbivore damage to cotton plants, which further demonstrates how difficult it is to generalize about the functional significance of these interactions.展开更多
Insects have evolved amazing methods of defense to ward off enemies. Many aphids release cornicle secretions when attacked by predators and parasitoids. These se cretions contain an alarm pheromone that alerts other c...Insects have evolved amazing methods of defense to ward off enemies. Many aphids release cornicle secretions when attacked by predators and parasitoids. These se cretions contain an alarm pheromone that alerts other colony members of danger, thereby providing indirect fitness benefits to the releaser. In addition, contact with cornicle se cretions could also threaten an attacker and could provide direct fitness to the releaser. However, cornicle secretions may also be recruited as a kairomonal cue by aphid natural enemies. In this study, we investigated the effect of the cornicle droplet volatiles of the cabbage aphid, Brevicoryne brassicae （L.）, on the hostsearching behavior of naive and experienced female Diaeretiella rapae （M＇Intosh） parasitoids in olfactometer studies. In addition, we evaluated the role ofB. brassicae cornicle droplets on the oviposition prefer ence of the parasitoid in a twochoice bioassay. Naive females did not exhibit any preference between volatiles from aphids secreting cornicle droplets over nonsecreting aphids, while experienced parasitoids exploited the secretions in their host location. Experienced females were also able to choose volatiles from both secreting and nonsecreting aphids over clean air, while this ability was not observed in naive females. Although secretion of cornicle droplets did not influence the percentage of first attack in either naive or experienced females, the success of attack （i.e. resulting in a larva） was significantly different between secreting and nonsecreting aphids in the case of experienced parasitoids.展开更多
The potato psyllid, Baetericera （= Paratrioza） cockerelli （gulc） （Hemiptera： Triozidae）, is a major pest of potato. Studies were conducted to determine the age at which both males and females reach reproductive...The potato psyllid, Baetericera （= Paratrioza） cockerelli （gulc） （Hemiptera： Triozidae）, is a major pest of potato. Studies were conducted to determine the age at which both males and females reach reproductive maturity and the effect of age and time of day on sex attraction. Adult B. cockerelli reach reproductive maturity within 48 h post-eclosion, with females being mature on the day of eclosion and males at 1 day post-eclosion. Oviposition generally began 2 days after mating but was delayed when females mated within 2 days post-eclosion. In laboratory olfactometer assays, the age of females used as odor sources and the age of males assayed to these odors did not affect sex attraction, with both younger （1-4-day-old） and older （8-10-day-old） males being attracted to females, regardless of female age （1-4-day-old or 8-10-day-old）. Males assayed to live females at different times during the photophase （between 8：00 and 20：00 hours） were attracted to females between 11：00 and 17：00 hours, showing a temporal periodicity in sex attraction with B. cockerelli at least during the photophase.展开更多
Egg parasitoids are known to use a wide range of chemicals, emitted by plants, host eggs or adults, for host selection. The effect of the sex pheromone components of the lepidopteran olive pests Prays oleae （Lepidopt...Egg parasitoids are known to use a wide range of chemicals, emitted by plants, host eggs or adults, for host selection. The effect of the sex pheromone components of the lepidopteran olive pests Prays oleae （Lepidoptera： Yponomeutidae） and Palpita unionalis （Lepidoptera： Pyralidae） was studied under laboratory conditions, on the foraging behaviour of the egg parasitoid Trichogramma oleae （Hymenoptera： Trichogrammatidae）. The re- sponse of T. oleae wasps to （Z）-7-tetradecenal and （E）-1 l-hexadecenal, major sex phero- mone components ofP. oleae and P. unionalis respectively, depended on the dose of the pheromone used in a Y-tube olfactometer bioassay. （E）-11-hexadecenal elicited maximum attraction （70%） at a dose of 1 pg, while a dose of 100 pg （Z）-7-tetradecenal attracted 80% of the tested wasps. （E）-11-hexadecenyl acetate, the second sex pheromone component of P. unionalis, and the binary blend of（E）-i 1-hexadecenyl acetate： （E）-11-hexadecenal （7：3） were not attractive at these doses. The results of this research are discussed in view that they may be considered as alternatives in the biological control of these pests.展开更多
基金This research was funded by the Shanxi Provincial Key Research and Development Project,China(201803D221004-8)the earmarked fund for China Agriculture Research System(CARS-08-G10)+1 种基金the Research and Demonstration of Key Green Technology for High Quality of Coarse Cereals in Northwest Shanxi(201703D211002-8)the Shanxi Province Science Foundation for Youths(201801D221305).
文摘Host-plant volatiles play an important role as cues for herbivores in search of resources, mates and oviposition sites in complex environments. Plant volatile-based attractants can be developed for pest monitoring and control. Previously, we indicated that mated female adults of Callosobruchus chinensis showed choice preference behavior toward 2-hexenal and benzaldehyde. Our objective here was to investigate the synergistic effect of host-derived attractive volatiles in attracting C. chinensis under laboratory and field conditions in Shanxi Province, China. We hypothesized that the ratio and concentration of volatiles derived from Vigna radiata play critical roles for C. chinensis in locating this host. Therefore, we collected and identified the volatiles of mungbean by using headspace collection and GC-MS. The effectiveness of different ratios and concentrations of two compounds (2-hexenal and benzaldehyde) that elicit C. chinensis searching behavior were examined in Y-tube olfactometer assays. The combination of 300 μg μL^–1 2-hexenal and 180 μg μL^–1 benzaldehyde loadings exhibited a synergistic effect on attracting C. chinensis (82.35%). Compared to control traps, the adults were significantly attracted to traps baited with blends, and more attraction to females than males was found for blend traps in the field experiments. Our results suggest that blends of this specific concentration and ratio of benzaldehyde and 2-hexenal can be used in traps as attractants for C. chinensis monitoring and control in the field.
文摘Turmeric (<i>Curcuma</i><span> <i>longa</i> L</span><span><span><span style="font-family:;" "="">.</span></span></span><span><span><span style="font-family:;" "="">) </span></span></span><span><span><span style="font-family:;" "="">is one of the essential condiments all over the world. Turmeric is an important medicine in the eastern medical systems and its therapeutic properties have been well recorded. Curcumin, commonly called diferuloyl methane (hydrophobic polyphenol), was studied extensively for its biological properties. Sri Lankan turmeric records relatively higher percentage (up to 9%) of curcumin. The bioactive compounds with insecticidal or pesticidal activity w</span></span></span><span><span><span style="font-family:;" "="">ere</span></span></span><span><span><span style="font-family:;" "=""> studied from the Sri Lankan turmeric as there is an increasing demand for natural products to control ticks and fleas in dogs against the chemicals that induce some secondary effects. Fifty grams (50 g) of dried coarsely ground turmeric (<i>Curcuma</i><span> <i>longa</i> L</span></span></span></span><span><span><span style="font-family:;" "="">.</span></span></span><span><span><span style="font-family:;" "="">)</span></span></span><span><span><span style="font-family:;" "=""> was subjected to sequential extractions with four different solvents in ascending order of polarity <span>using Soxhlet apparatus.</span></span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span><span><span style="font-family:;" "="">The treatments consisted of solvent-fractionated tur</span></span></span><span><span><span style="font-family:;" "="">meric extracts from hexane, dichloromethane (CH<sub>2</sub>Cl<sub>2</sub>), ethyl acetate (EtOAc) and Methanol (CH<sub>3</sub>OH) dissolved in the water to 100 ppm. The test carried out using a modified olfactometer and the degree of repellency of common tick species <i>Rhipicephalus</i></span></span></span><span><span><i><span style="font-family:;" "=""> </span></i></span></span><span><span><i><span style="font-family:;" "="">sanguineus</span></i></span></span><span><span><span style="font-family:;" "=""> was recorded. The hexane extract from dried turmeric powder showed the highest repellence of 80% whereas other fractions showed lesser repellence. Further studies in the direction of purification, dose dependent repellency and persistency.</span></span></span>
基金the National Natural Science Foundation of China(grant nos.31972263,31901878 and 31772160)China Postdoctoral Science Foundation(grant no.2019M653773)。
文摘Chemosensory systems are considered to play an important role in host plant selection in herbivorous insects.However,few studies have focused on chemosensory proteins(CSPs)for aphid host-location mechanisms.The roles of CSPs in searching for different Poaceae species(wheat,barley,triticale,maize and sorghum)were tested in Rhopalosiphum padi,an important cereal pest.The olfactometer assays showed that R.padi responds to plant odors.Seven R.padi CSP genes were identified.Influence of aphid morph,tissue and starvation state on expression patterns of CSPs was evaluated.Expression levels of CSPI,CSP4,CSP5 and CSP6 in winged aphids were significantly higher than those in wingless ones.Transcription levels of four genes(CSPI,CSP4,CSP5 and CSP6)were relatively higher in the head with antennae,and the four genes tended to be upregulated follow ing starvation.Silencing of three CSPs(CSP4,CSP5 and CSP6)altered aphid host-location behavior in response to the five different host plants tested.Three volatile compounds of host plants(octanal,[E]-2-hexenol and linalool)have signif-icant attraction to winged R.padi according to the four-arm olfactometer tests.Molecular docking predicted hydrogen bonding sites which played key roles in the binding of CSP4,CSP5 and CSP6 with volatile compounds.Knockdown of CSP4 or CSP5 significantly decreased the staying time of R.padi in the arms with octanal.However,knockdown of CSP6 could not affect the response of R.padi to octanal.These results bring evidence for the involvement of three CSPs in R.padi host-location behavior.
文摘We investigated the responses of 3 thrips species, Frankliniella schultzei Tryborn, E occidentalis Pergrande, and Thrips tabaci Lindeman （Thysanoptera： Thripidae） to herbivore-damaged and undamaged cotton seedlings （Gossypium hirsutum L. [Malvales： Malvaceae]） at a range of time intervals following damage by adult Tetranychus urticae （Koch）, adult T. ludeni （Zacher） （Acari： Tetranychidae） or Helicoverpa armigera （Hubner） （Lepidoptera： Noctuidae） larvae in olfactometer assays. The intensity/frequency of the response of thrips to herbivore-induced plants decreased with time and ultimately disappeared in all cases; however, the rate at which the response declined was related to the herbivore species that inflicted the damage. All 3 species of thrips were attracted to plants damaged by T. urticae for longer than they were to plants damaged by T. ludeni. The duration for which damaged plants remained attractive was also affected by the degree of damage inflicted on cotton seedlings. For example, E schultzei was attracted to plants damaged by a higher density of two-spotted spider mites （100/plant） for much longer than to plants damaged by a lower density of these mites （50/plant）. The results reinforce previous studies that demonstrate that arrangement of variables influences the responses of thrips to their herbivore-induced cotton host plants. Results also show that these responses are variable in time following herbivore damage to cotton plants, which further demonstrates how difficult it is to generalize about the functional significance of these interactions.
文摘Insects have evolved amazing methods of defense to ward off enemies. Many aphids release cornicle secretions when attacked by predators and parasitoids. These se cretions contain an alarm pheromone that alerts other colony members of danger, thereby providing indirect fitness benefits to the releaser. In addition, contact with cornicle se cretions could also threaten an attacker and could provide direct fitness to the releaser. However, cornicle secretions may also be recruited as a kairomonal cue by aphid natural enemies. In this study, we investigated the effect of the cornicle droplet volatiles of the cabbage aphid, Brevicoryne brassicae （L.）, on the hostsearching behavior of naive and experienced female Diaeretiella rapae （M＇Intosh） parasitoids in olfactometer studies. In addition, we evaluated the role ofB. brassicae cornicle droplets on the oviposition prefer ence of the parasitoid in a twochoice bioassay. Naive females did not exhibit any preference between volatiles from aphids secreting cornicle droplets over nonsecreting aphids, while experienced parasitoids exploited the secretions in their host location. Experienced females were also able to choose volatiles from both secreting and nonsecreting aphids over clean air, while this ability was not observed in naive females. Although secretion of cornicle droplets did not influence the percentage of first attack in either naive or experienced females, the success of attack （i.e. resulting in a larva） was significantly different between secreting and nonsecreting aphids in the case of experienced parasitoids.
文摘The potato psyllid, Baetericera （= Paratrioza） cockerelli （gulc） （Hemiptera： Triozidae）, is a major pest of potato. Studies were conducted to determine the age at which both males and females reach reproductive maturity and the effect of age and time of day on sex attraction. Adult B. cockerelli reach reproductive maturity within 48 h post-eclosion, with females being mature on the day of eclosion and males at 1 day post-eclosion. Oviposition generally began 2 days after mating but was delayed when females mated within 2 days post-eclosion. In laboratory olfactometer assays, the age of females used as odor sources and the age of males assayed to these odors did not affect sex attraction, with both younger （1-4-day-old） and older （8-10-day-old） males being attracted to females, regardless of female age （1-4-day-old or 8-10-day-old）. Males assayed to live females at different times during the photophase （between 8：00 and 20：00 hours） were attracted to females between 11：00 and 17：00 hours, showing a temporal periodicity in sex attraction with B. cockerelli at least during the photophase.
文摘Egg parasitoids are known to use a wide range of chemicals, emitted by plants, host eggs or adults, for host selection. The effect of the sex pheromone components of the lepidopteran olive pests Prays oleae （Lepidoptera： Yponomeutidae） and Palpita unionalis （Lepidoptera： Pyralidae） was studied under laboratory conditions, on the foraging behaviour of the egg parasitoid Trichogramma oleae （Hymenoptera： Trichogrammatidae）. The re- sponse of T. oleae wasps to （Z）-7-tetradecenal and （E）-1 l-hexadecenal, major sex phero- mone components ofP. oleae and P. unionalis respectively, depended on the dose of the pheromone used in a Y-tube olfactometer bioassay. （E）-11-hexadecenal elicited maximum attraction （70%） at a dose of 1 pg, while a dose of 100 pg （Z）-7-tetradecenal attracted 80% of the tested wasps. （E）-11-hexadecenyl acetate, the second sex pheromone component of P. unionalis, and the binary blend of（E）-i 1-hexadecenyl acetate： （E）-11-hexadecenal （7：3） were not attractive at these doses. The results of this research are discussed in view that they may be considered as alternatives in the biological control of these pests.
