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1.
Several naturally discovered or laboratory-synthesized pyrrole compounds have insecticidal, acaricidal and microbial properties. The novel sulfanyl 5H-dihydro-pyrrole derivatives exhibit certain antioxidant activities. However, there is a knowledge gap whether these substances are potent grain protectants against stored-product insect pest species. In this context, we evaluated the insecticidal activity of five novel pyrrole derivatives (under the trivial names 3a, 3g, 3l, 3m, 3h), against larvae of Tribolium confusum Jaquelin du Val and Ephestia kuehniella Zeller at different doses (0.1, 1 and 10 ppm), exposure intervals (7, 14 and 21 days or 1, 2, 7, 14, 21 days), temperatures (20, 25 and 30 °C), relative humidity (RH) (55 and 75 %) levels and commodities (wheat, maize, barley). The pyrrole derivative 3a exhibited the highest insecticidal activity, while 3g, 3l, 3m and 3h caused similar mortality against larvae of T. confusum. Apart of the level of efficacy, all tested pyrrole derivatives performed similarly according temperature. We found that increase in temperature increased mortality in the majority of the tested combinations. Generally, the pyrrole derivatives caused the highest mortality levels at 30 °C. The pyrrole derivatives 3a, 3g, 3l and 3m were affected by relative humidity at almost all combinations tested. The 75 % level of RH moderated the efficacy of the pyrrole derivatives, while the 55 % enhanced it. Mortality of T. confusum and E. kuehniella on maize was much lower on treated maize than barley or wheat. However, 100 % control of both species was recorded only on treated barley. The results of the present study indicate that the pyrrole derivatives tested could serve as grain protectants against noxious stored-product insects under certain biotic and abiotic conditions.  相似文献   

2.
The insecticidal effect of low temperatures for the control of all life stages of two stored-product insects, Plodia interpunctella and Liposcelis bostrychophila, was evaluated under laboratory conditions. The temperatures tested were 0, ??5, ??10 and ??15 °C, and, at these temperatures, the insects were exposed for 2, 4 and 8 h and also for 1, 2, 3 and 7 days. Regarding P. interpunctella, the most cold-tolerant life stage was larvae, given that 2 days of exposure were needed for complete (100%) mortality at ??10 °C. Moreover, all larvae were dead at ??15 °C even after 2 h of exposure. Eggs of P. interpunctella were susceptible to cold, as mortality was complete after 7, 1 day, 2 and 2 h at 0, ??5, ??10 and ??15 °C, respectively. L. bostrychophila was by far less susceptible than P. interpunctella. For this species, adults were still alive even after 7 days at ??10 °C, while complete mortality was achieved only after 1 day at ??15 °C. Eggs of L. bostrychophila were the most cold-tolerant life stage, as survival was observed even after 3 days at ??15 °C. The results of the present study provide the first data set on which all life stages of P. interpunctella and L. bostrychophila are evaluated for their susceptibility to cold treatments in a standardized series of exposures and temperatures. These results are expected to further encourage the “real world” application of cold treatments for the disinfestation of durable stored-products.  相似文献   

3.
This paper evaluated the density and biological resistance of pinewood samples modified with thermo-mechanical densification and thermal post-treatment. The samples were densified with 20 and 40% compression ratios at either 110 or 150 °C. The thermal post-treatment was then applied to the pine samples at 185 and 212 °C for 2 h. These samples were exposed to white-rot (Trametes versicolor) and brown-rot (Coniophora puteana) fungi for twelve weeks and the resulting mass loss was determined. In the densified samples, the effects of the compression ratio on T. versicolor-initiated mass loss and of the compression temperature on C. puteana-initiated mass loss were found to be significant. The mass loss was less in the samples compressed at 150 °C with the 40% ratio, while the highest mass loss was observed in the undensified samples. In the thermally post-treated samples, the resistance to both decay fungi was significantly increased with the increase of the treatment temperature. The mass loss in the thermally post-treated samples at 212 °C after T. versicolor and C. puteana fungi testing was reduced by 73 and 67%, respectively. However, the effect of the densification processes on decay resistance in the thermally post-treated samples was insignificant.  相似文献   

4.
In the present work, a lethality index was applied for the evaluation of three insecticides with different modes of action, i.e., thiamethoxam, chlorfenapyr and lambda-cyhalothrin, as surface treatment against adults of Sitophilus oryzae (L.), Oryzaephilus surinamensis (L.) and Tribolium confusum Jacquelin du Val, in laboratory bioassays. The insecticides were applied at their highest label dose, while insect knockdown and mortality were evaluated after 1, 3, 5 and 7 days of exposure to the treated surfaces according to the Standardized Lethality Index, by ranking each insect from “0” to “4,” with “0” corresponding to insects moving normally and “4” corresponding to dead individuals. After the end of the exposure, the surviving insects were transferred to clean, untreated dishes and delayed mortality was assessed after an additional period of 1, 3, 5 and 7 days. Based on the results, initial knockdown was high for S. oryzae after exposure to thiamethoxam and lambda-cyhalothrin even after 1 day of exposure, whereas for longer exposures high mortality levels were recorded. In contrast, in the case of chlorfenapyr knockdown was low after 1 day of exposure; however, high mortality levels were noted after 3 and 5 days of exposure. Similar results were noted for O. surinamensis, which was highly susceptible to all three insecticides tested. The most tolerant insect species to the tested insecticides was T. confusum, since a noticeable number of T. confusum adults were still active at the end of the exposure (7 days). Our results indicate that knockdown is most likely to lead to mortality than to recovery, but there were important differences among the three insecticides tested.  相似文献   

5.
Lateralization (i.e. left–right asymmetries in the brain and behaviour) has been documented in all vertebrate classes, while evidences for invertebrates are limited. To the best of our knowledge, there is no information about behavioural asymmetries in the order Coleoptera. In this research, we investigated the lateralization of mating traits in two major pests of stored products: the rice weevil, Sitophilus oryzae (Coleoptera: Curculionidae), and the confused flour beetle, Tribolium confusum (Coleoptera: Tenebrionidae). Both T. confusum and S. oryzae males showed population-level left-biased copulation approaches of potential mates. Interestingly, T. confusum and S. oryzae males performing left-biased copulation attempts achieved higher mating success over right-biased males. Furthermore, S. oryzae males periodically exhibited a typical head wagging behaviour, which consists of waving the rostrum laterally across the female thorax and then resting the rostrum on the mid thorax. This behaviour was right-biased, even in the majority of males that previously showed left-biased copulation attempts. The quantification of mating displays could allow comparisons with other strains, in order to evaluate the impact of a given host or of the rearing methods on the mating traits of S. oryzae and T. confusum. Overall, this is the first report of lateralization of mating traits in Coleoptera. Furthermore, this research adds basic knowledge to the reproductive behaviour of S. oryzae and T. confusum.  相似文献   

6.
We evaluated the antifungal and antitermite activities of wood vinegars produced from oil palm trunk. The wood vinegars were produced at three different pyrolysis temperatures, 350, 400, and 450 °C. Antifungal activities of vinegars were evaluated using a Petri dish bioassay with 0.5, 1.0, and 1.5% (v/v) against a white-rot fungus, Trametes versicolor, and a brown-rot fungus, Fomitopsis palustris. Antitermite activities were tested using a no-choice bioassay method for Coptotermes formosanus with 2.5, 5.0, 7.5, and 10.0% (v/v). All the wood vinegars exhibited antifungal activities against T. versicolor. In particular, the wood vinegar produced at 350 °C resulted in complete inhibition of T. versicolor growth at 1.0 and 1.5%. However, higher concentrations were required to obtain growth inhibition of F. palustris. All the wood vinegars exhibited antitermite activity to C. formosanus workers in the no-choice experiment at relatively high concentrations. For instance, 10% concentration was required to achieve 100% mortality against C. formosanus at all production temperatures. The lowest mass loss of the treated filter paper of 11.75% was obtained with a 350 °C—10.0% combination.  相似文献   

7.
The extensive use of synthetic insecticides and fumigants for control stored-product insects has led to the development of resistance. Essential oils from aromatic plants may provide proper alternatives to currently used insect control agents. Essential oils from 20 Egyptian plants were obtained by hydrodistillation. The chemical composition of the oils was identified by gas chromatograph/mass spectrometer. Fumigant and contact toxicities of the essential oils were evaluated against Sitophilus oryzae. The inhibitory effects of the essential oils on acetylcholinesterase and adenosine triphosphatases activities were examined. The oils were composed of monoterpene hydrocarbons (i.e., limonene, sabinene, β-pinene and γ-terpinene) and oxygenated monoterpenes (i.e., terpinen-4-ol, β–thujone, 4-terpineol, α-citral and 1,8-cineole) with the exception of the oil of Schinus terebinthifolius which was contained sesquiterpenes, and the oil of Vitex agnus-castus which contained similar amounts of monoterpenes and sesquiterpenes. In the fumigation assay, the oils of Origanum vulgare (LC50 = 1.64 mg/L air), Citrus lemon (LC50 = 9.89 mg/L air), Callistemon viminals (LC50 = 16.17 mg/L air), Cupressus sempervirens (LC50 = 17.16 mg/L air), and Citrus sinensis (LC50 = 19.65 mg/L air) showed high toxicity to S. oryzae. In the contact assay, the oils of Artemisia judaica, C. viminals, and O. vulgare caused the highest toxicity to S. oryzae with LC50 values of 0.08, 0.09, and 0.11 mg/cm2, respectively. The oil of A. judaica (I50 = 16.1 mg/L) invoked the highest inhibitory effect on AChE activity, while the oils of C. viminals and O. vulgare were the most potent inhibitors to ATPases activity with I50 values of 4.69 and 6.07 mg/L, respectively. The results indicate that the essential oils of A. Judaica, O. vulgare, C. limon, C. viminals, and C. sempervirens could be applicable to the management of populations of S. oryzae.  相似文献   

8.
The influence of moisture content (MC) on the orthotropic viscoelasticity of Chinese fir wood (Cunninghamia lanceolata [Lamb.] Hook.) has been examined in low temperature environment. Storage modulus E′ and loss modulus E″ of wood with six different levels of MC ranging from 0.6 to 22.0% were determined from ??120 to 40 °C and at multi-frequency range of 0.5, 1, 2, 5, and 10 Hz using a TA instruments® Dynamic Mechanical Analyzer (DMA 2980). The results showed that a distinct moisture dependency is exhibited by the orthotropic viscoelastic behaviour of Chinese fir wood. With the exception of some apparent activation energy (ΔE) for β-relaxation process, the E′ decreased and the E″ peak temperatures moved towards lower temperature and the ΔE for α-relaxation process became lower with MC increasing in all orthotropic directions, whereby individual decline of E′ and the E″ peak temperatures were affected by MC to different degrees. Besides, a little E″ peak at around 0 °C was only seen in L direction, which could be attributed to the melting of frozen water. Furthermore, the dynamic viscoelastic behavior of wood is also dependent on the measurement frequency. The findings suggest that the orthotropic structure and moisture content have an important influence on the viscoelastic performance in low temperature environment.  相似文献   

9.
10.
Apparent digestibility and nitrogen (N) balance were evaluated in sheep fed low-quality Cynodon nlemfuensis grass supplemented with different foliages of forage-potential trees. Four male hair sheep were housed in metabolic cages and fed in a Latin Square design with 30 % inclusion of foliage of Erythrina indica (Ei), Moringa oleifera (Mo), or Trichanthera gigantea (Tg) replacing soybean meal. Adaptation and faeces and urine collection periods were 14 and 7 days, respectively. Sheep received 70 g DM/kg/BW0.75 of the diet in order to achieve total consumption of feed. Dry matter, organic matter, and neutral detergent fiber digestibilities were similar (P > 0.05) among the control, Mo, and Ei diets, while the Tg diet resulted in the lowest (P < 0.05) value. The Ei diet showed the highest (P < 0.05) total N intake among the three diets with 30 % of leaf meal, which was similar (P > 0.05) to the control diet. N excreted in faeces was highest (P < 0.05) in the Tg diet when compared to the other leaf meal diets, in which the Mo diet presented the lowest (P < 0.05) value, but was similar (P > 0.05) to that found in the control diet. The Mo and Ei diets had similar (P > 0.05) values for the percent of N absorbed by the animals, which was much higher (P < 0.05) than that of the Tg diet. The forage of M. oleifera and Ei can be used in diets at 30 % incorporation to substitute the use of soybean meal in small ruminant production.  相似文献   

11.
Soil organic carbon (SOC) plays an important role in soil fertility and productivity. It occurs in soil in labile and non-labile forms that help in maintaining the soil health. An investigation was undertaken to evaluate the dynamics of total soil organic carbon (C tot), oxidisable organic carbon (C oc), very labile carbon (C frac 1), labile carbon (C frac 2), less labile carbon (C frac 3), non-labile carbon (C frac 4), microbial biomass carbon (C mic) and SOC sequestration in a 6-year-old fruit orchards. The mango, guava and litchi orchards caused an enrichment of C tot by 17.2, 12.6 and 11 %, respectively, over the control. The mango orchard registered highest significant increase of 20.7, 13.5 and 17.4 % in C frac 1, C frac 2 and C frac 4, respectively, over control. There is greater accumulation of all the C fractions in the surface soil (0–0.30 m). The maximum total active carbon pool was 36.2 Mg C ha?1 in mango orchard and resulted in 1.2 times higher than control. The passive pool of carbon constituted about 42.4 % of C tot and registered maximum in the mango orchard. The maximum C mic was 370 mg C kg?1 in guava orchard and constituted 4.2 % of C tot. The carbon management index registered 1.2 (mango orchard)- and 1.13 (guava and litchi orchard)-fold increase over control. The mango orchard registered highest carbon build rate of 1.53 Mg C ha?1 year?1 and resulted in 17.3 % carbon build-up over control. Among the carbon fractions, C frac 1 was highly correlated (r = 0.567**) with C mic.  相似文献   

12.
Nontimber forest products are a source of income for women in rural African communities. However, these products are frequently damaged by insect pests. The present study investigates the diversity and damage rates of insect pests that attack Carapa procera seeds and Lophira lanceolata fruits. The experiment was set up in western Burkina Faso and, for C. carapa, consisted of pests collected from seeds that had fallen to the ground and from stockpiled seeds. For L. lanceolata, pests were collected from fruits on the trees, and on the ground. The collected samples were sent to the laboratory to estimate the proportion of damaged seeds/fruits and rear the insects. The results showed that Ephestia spp., Tribolium castaneum, Oryzeaphilus spp., and Tenebroides mauritanicus were the pests of Carapa procera seeds and Lophira lanceolata fruits. Ephestia spp. was recorded as the main pest of both C. procera and L. lanceolata, whereas T. castaneum was only detected from seeds of L. lanceolata. For C. procera, the stocks were the most infested (29 %) by Ephestia spp. The infestation rate of fruits of L. lanceolata by Ephestia spp. on trees (31.42 ± 3.75 %) was less than the rate of fruits by T. castaneum on the ground (44.00 ± 3.5 %). The different body sizes of Ephestia spp. may indicate the occurrence of two putative species, one from C. procera and another one from L. lanceolata. This work provides important information that could contribute to the setting up of a local-scale sustainable management framework for oil tree pests in Burkina Faso and surrounding countries.  相似文献   

13.
The codling moth (Cydia pomonella L.) is a significant pest of pome fruit throughout the world. Behavioral and ovicidal activities of five non-host plant extracts (Arctium lappa, Bifora radians, Humulus lupulus, Verbascum songaricum, Xanthium strumarium), synthetic sex pheromone, (E,E)-8,10-dodecadienol (codlemone), and the plant volatile lure, (2E,4Z)-2,4-decadienoate (pear ester) were evaluated against the codling moth, C. pomonella L. Codlemone elicited the greatest electroantennogram (EAG) response (6.2 ± 1.2 mV) of the compounds tested from male C. pomonella while pear ester elicited 1.7 ± 0.1 mV EAG response in female moths. Codlemone attracted 34.5% of male C. pomonella in olfactometer studies, and it was followed by the X. strumarium extract with 24.8%. There was a significant difference between the behavior of unmated and mated females. V. songaricum extract was the most active extract, attracting 25.4% of unmated females. However, mated C. pomonella females exhibited greatest attraction to pear ester. In a wind tunnel bioassay, combining X. strumarium with codlemone significantly increased the response of male upwind flight and source contact as compared with codlemone alone. All plant extracts, except for V. songaricum, significantly reduced the number of eggs laid. The plant extracts exhibited some toxic effects to eggs, and hatching rate of eggs was reduced as compared with the control. Our results indicate that some of the plant extracts tested are potential candidates for practical use after elucidation and characterization of active compound(s).  相似文献   

14.
Nutrient (NH4, PO4 and K) leaching from oven dried green leaves of Emblica officinalis Gaerten, Sesbania grandiflora (L.) Pers. and Moringa oleifera Lam.were investigated in laboratory condition. Oven-dried green leaves were immersed in demineralized distilled water for 8 days. Electrical conductivity (EC), Total dissolved solids (TDS) and nutrients (NH4, PO4 and K) of leaching water samples were measured at 0.25, 0.5, 1, 2, 3, 4, 6, 8, 12, 24, 48, 72, 96, 144, and 192 h of intervals. All these species showed an increasing trend for EC and TDS in leachate and comparatively higher EC and TDS were observed in E. officinalis, which is followed, by S. grandiflora and M. oleifera. Significantly high amount (P < 0.05) of NH4 was leached from S. grandiflora and PO4 from M. oleifera. But, both S. grandiflora and M. oleifera leached significantly higher (P < 0.05) K than E. officinalis. Within the first 0.25 h, 100 % and 82 % of NH4 and 68 % and 74 % of K were leached from leaves of S. grandiflora and M. oleifera respectively. S. grandiflora and M. oleifera leached 100 % of PO4 within 6 h. The concentrtions of NH4, PO4 and K in the leachate from E. officinalis, S. grandiflora and M. oleifera were not significantly different (P > 0.05). The green leaves of S. grandiflora and M.oleifera can be a potential source of NH4, PO4 and K for a quick nutrient supplement to the agricultural crops in agroforestry practices.  相似文献   

15.
The study aimed to test the potential anthelmintic activity of Salix babylonica (SB) extract for the control of gastrointestinal and pulmonary parasites in sheep and goats under field conditions. A representative sample of 20 % of all animals reared in 8 sheep and 7 goat farms was used in the study. Animals from each farm were randomly selected for a total number of 93 sheep and 75 goats. Animals suffered a natural gastrointestinal nematode infection and had never been treated with chemical anthelmintic drugs. The SB extract (20 mL) was orally administered weekly before the morning feeding to each animal for 60 days. Fecal eggs or oocysts were counted at 0, 1, 20, 40, and 60 days after starting the extract administration. Differences (P < 0.01) in the fecal oocyst and egg output of Eimeria, Dictyocaulus, and Moniezia were observed between sheep and goats. In addition, the treatment influenced (P < 0.05) egg outputs of Cooperia, Dictyocaulus, and Trichuris. Fecal egg or oocyst counts of Haemonchus contortus, Eimeria, Cooperia, Chabertia, Dictyocaulus, Moniezia, and Ostertagia were time-dependent (P < 0.05). For sheep, administration of SB decreased (P < 0.05) the fecal eggs count of H. contortus, Cooperia, Chabertia, Dictyocaulus, Moniezia, and Trichuris. After 20 days of treatment, H. contortus, Cooperia, or Moniezia were not detected. For goats, SB reduced (P < 0.05) the fecal egg counts of H. contortus, Cooperia, Chabertia, and Moniezia. Moreover, decreases were observed (P < 0.05) for Chabertia, Trichostrongylus, and Ostertagia. Eggs of H. contortus and Moniezia were not present in the feces after 1 day of administration of the extract. It could be concluded that the weekly administration of SB extract at 20 mL per animal can be used to treat gastrointestinal and lung nematodes of small ruminants in organic and traditional farming systems of tropical regions.  相似文献   

16.
We studied leaf litter fall, decomposition and nutrient release patterns of Shorea robusta and Tectona grandis by using a litter bag technique to better understand the release pattern of nutrients to soil from leaf litter. Annual litterfall varied from 13.40 ± 2.56 t ha?1 a?1 for S. robusta to 11.03 ± 3.72 t ha?1 a?1 for T. grandis and the decay constant (k) of decomposed leaf litter was distinctly higher for T. grandis (2.70 ± 0.50 a?1) compared to S. robusta (2.41 ± 0.30 a?1). Biomass loss was positively correlated with the initial litter C, WSC, C/N and ash content in S. robusta and N, P and K concentration for T. grandis. Biomass was negatively correlated with lignin and L/N ratio for S. robusta and L, WSC, L/N and C/N ratio for T. grandis (P < 0.01). Nutrient use efficiency (NUE) and nutrient accumulation index (NAI) of S. robusta was higher than for T. grandis. The retranslocation of bioelements from senescent leaves ranked as P > N > K. Annual N, P and K input to soil through litterfall differed significantly between the two species in the following order: N>K>P. S. robusta was superior in terms of K and P return and T. grandis was superior in terms of N return. The two tree species showed a similar patterns of nutrient release (K > P > N) during decomposition of their leaf litter. Nutrients of N, K and P were the primary limiting nutrients returned to soil through litterfall with important roles in soil fertility and forest productivity.  相似文献   

17.
The legume Cratylia argentea associated to Brachiaria brizantha—Toledo-grass (Bb + Ca) and Toledo-grass alone (Bb) were evaluated under grazing conditions by Holstein × Zebu heifers. Three evaluation periods during three consecutive years, were performed. We measured, daily live-weight gains of heifers (DWG, g/day); biomass dry matter (BDM, kg/ha) at beginning and end of each grazing period. On plant samples, were measured percentages of crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), lignin, in situ DM degradability (ISDMD), and voluntary biomass DM intake (VBI, g/LW0.75) using the Cr2O3/in situ indigestibility technique. A completely randomized design was applied, using heifers as experimental units for DWG gains and VBI. At the beginning of the grazing, the BDM for Bb + Ca and Bb–considering the three periods-averaged, 3065 and 936 kg/ha, respectively. Crude protein content of C. argentea was around 20 %; and for Bb + Ca or Bb, ranged from 8.7 to 4.6 %. In either treatment, in situ DM degradability averaged 72.6 % (P ≥ 0.05), regardless of the botanical component type. Biomass DM intake was 83.02 (Bb + Ca) and 89.22 (Bb) g/LW0.75. The DWG gains (g/heifer) for Bb + Ca and Bb were (per period): 829 and 574 (first); 469 and 118 (second); and 534 and 508 (third). This study showed that the Bb + Ca association was better to improve the daily gain of F1 Holstein × Zebu heifers, as compared to Bb alone. Also, C. argentea associated to a low to medium-quality grass improved the nutritional value of the diet without affecting the biomass DM intake.  相似文献   

18.
Volatile organic compounds (VOCs) released from Chamaecyparis formosensis, Cryptomeria japonica, Cunninghamia lanceolata, Chamaecyparis obtusa var. formosana, and Taiwania cryptomerioides five major building and interior decoration timbers and their essential oil components were analyzed using GC–MS and TD/GC–MS/FID. Results showed that C. obtusa var. formosana had the highest yield of essential oil (3.42%), followed by C. formosensis (3.14%), while C. japonica had the lowest yield (0.95%). Moreover, oxygenated sesquiterpene was the highest relative content in all five essential oils and their main constituents were trans-myrtanol (18.04%), 1-epi-cubenol (15.99%), cedrol (62.26%), α-cadinol (26.42%), and α-cadinol (27.98%), respectively. In terms of emission quantity of top VOC, the results showed the decreasing order of C. formosensis (myrtenal, 74.21 mg/m2)?>?T. cryptomerioides (thujopsene, 12.00 mg/m2)?>?C. lanceolata (α-cedrene, 10.27 mg/m2)?>?C. obtusa var. formosana (α-pinene, 8.05 mg/m2)?>?C. japonica (α-cedrene, 4.25 mg/m2). C. formosensis had a greater amount of VOCs emitted and hence gave off more fragrance than C. obtusa var. formosana initially. However, after indoor exposure of 24 weeks, the VOC emission quantity of C. obtusa var. formosana exceeded that of C. formosensis. α-Cedrene and thujopsene were the top two major VOCs of both C. lanceolata and T. cryptomerioides. However, they both showed a trend of decrease in emission with prolonged exposure. All five plantation timbers showed good antifungal, antimicrobial, antibacterial, and antitermitic properties, making them ideal materials for interior decoration. Not only do they have strong bioactivities, they can also provide a fragrant and healthy living environment.  相似文献   

19.
Gardenia jasminoides and Rosa chinensis are economically important horticultural plants in China. Frankliniella occidentalis and Thrips hawaiiensis are serious coexisting pests that previously demonstrated opposite population trends on G. jasminoides and R. chinensis flowers. To further study the different performances between F. occidentalis and T. hawaiiensis, we investigated their population dynamics in the field (for 5 years) and their life history characteristics on the two flowers in the laboratory. In the field, the density of F. occidentalis was lower than that of T. hawaiiensis on G. jasminoides but was higher than that of T. hawaiiensis on R. chinensis. Under laboratory conditions, F. occidentalis showed significantly slower development, and lower survival and fecundity levels than T. hawaiiensis on G. jasminoides, but the opposite was true on R. chinensis. Significant differences in the net reproductive rate (R 0) between F. occidentalis and T. hawaiiensis were observed, with respective values of 38.66 ± 2.85 and 47.91 ± 2.70 on G. jasminoides, and 55.64 ± 2.15 and 32.45 ± 2.16 on R. chinensis. The intrinsic rates of increase (r m ) of F. occidentalis and T. hawaiiensis were 0.156 ± 0.008 and 0.198 ± 0.007, respectively, on G. jasminoides, and 0.172 ± 0.003 and 0.165 ± 0.002, respectively, on R. chinensis. Thus, the performances of both thrips with respect to population size in the laboratory were in accordance with those in the field, suggesting that the innate capacity for insect population increases may directly impact their population dynamics in fields. Thus, the population performance of different thrips species on flowers is species-dependent, which could be exploited in thrips control programs by breeding pest-resistant cultivars.  相似文献   

20.
Knowledge regarding the interactive effects of elevated [CO2], warming and drought on dry mass production, allocation and water use efficiency (WUE) of tree seedlings is limited, particularly in trees exhibiting different stomatal regulation strategies. Seedlings of Callitris rhomboidea (relatively anisohydric) and Pinus radiata (relatively isohydric) were grown in two [CO2] (Ca (400 μmol mol?1) and Ce (640 μmol mol?1)) and two temperature (Ta (ambient) and Te (ambient?+?4 °C)) treatments in a sun-lit glasshouse under well-watered conditions prior to imposition of the drought. Ce increased mass production in C. rhomboidea (but not in P. radiata), while drought limited mass production in both species. Mass production was greatest in the combination of Ce, Te and well-watered conditions. Pinus radiata allocated relatively more dry mass into roots and had higher plant WUE than C. rhomboidea. Noticeably, mass allocation patterns in C. rhomboidea varied as a function of the treatments, but those of P. radiata were constant. Ce enhanced leaf WUE of both species, but to a greater degree under drought stress than well-watered conditions. Moderate drought stress increased both leaf and plant WUE compared to well-watered conditions. C. rhomboidea exhibited plasticity to variable climate conditions through morphological adjustments, while P. radiata exhibited a highly conservative strategy. Collectively, these findings indicate that the two species have different strategies in resource acquisition and utilisation under changing environmental conditions. Future studies on tree response to climate change need to fully consider the integration of species traits, including stomatal behaviour and hydraulic strategies.  相似文献   

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