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1.
The biology of the pentatomid Dichelops melacanthus (Dallas) feeding on cultivated and non-cultivated plants was studied in the laboratory. Nymph mortality varied from approximately 60 on corn (seed mature) to 77% on wheat (ear immature); no nymphs survived on seedlings of corn or wheat. Nymph developmental time on soybean, corn or wheat (seed, pod or ear) varied from 25.5 to 32.8 days. Body weight at adult emergence was similar and greater on most foods than on wheat ear. Nymphs fed preferentially on soybean (pod immature). On non-cultivated hosts, nymphs showed high mortality (73%) on crotalaria (pod immature); on tropical spiderwort (stem) all nymphs died. Nymphs took longer time to develop on crotalaria and/or on spiderwort than on soybean. Body weight at adult emergence did not differ on crotalaria or soybean. Survivorship decreased with time on most foods, with approximately 50% of adults alive at day 30. On corn and wheat seedlings approximately 80% of adults were dead on day 20. Adult longevity ranged 31-43 days, except on corn and wheat seedlings < 15 days. Females % ovipositing peaked ( approximately 76%) on soybean (pod or seed immature), and was minimum ( approximately 9%) on wheat ear (immature); no females reproduced on seedlings of corn or wheat. Preoviposition period was shorter ( approximately 12 days) on soybean (immature pod or seed) and longer ( approximately 37 days) on wheat (ear immature). Fecundity was similar and higher on all foods than on wheat (ear immature). Body weigh gain occurred on all foods, but on corn and wheat seedlings. Adults fed preferably on soybean (pod immature and seed mature); wheat (seedling) was the least preferred food.  相似文献   

2.
We report biological data of two generations of Amblyomma triste in laboratory and compared the suitability of different host species. Infestations by larval and nymphal stages were performed on guinea pigs (Cavia porcellus), chickens (Gallus gallus), rats (Rattus norvegicus), rabbits (Oryctolagus cuniculus), wild mice (Calomys callosus), dogs (Canis familiaris) and capybaras (Hydrochaeris hydrochaeris). Infestations by adult ticks were performed on dogs, capybaras and rabbits. Tick developmental periods were observed in an incubator at 27 degrees C and RH 90%. Guinea pigs were the most suitable hosts for larvae and nymphs, followed by chickens. The remaining host species were less suitable for immature ticks as fewer engorged ticks were recovered from them. Mean larval feeding periods varied from 3.8 to 4.7 d between different host species. Mean larval premolt periods ranged from 8.9 to 10.4 d. Nymphal mean feeding periods varied from 4.2 to 6.2 d for ticks fed on different host species. Premolt period of male nymphs (mean: 15.4 d) was significantly longer than that of female nymphs (14.7 d). Female nymphs were significantly heavier than male nymphs. The overall sex ratio of the adult ticks emerged from nymphs was 0.9:1 (M:F). Capybaras were the most suitable host for the tick adult stage as significantly more engorged females were recovered from them and these females were significantly heavier than those recovered from dogs or rabbits. The life cycle of A. triste in laboratory could be completed in an average period of 155 d. The potential role of guinea pigs, birds and capybaras, as hosts for A. triste in nature, is discussed.  相似文献   

3.
Between January 1999 and December 2000, 876 bird specimens were captured in three different ecological environments from the Reinhard Maack Park, Curitiba, State of Paraná, southern Brazil. A total of 142 birds (16.2%) were infested with Amblyomma aureolatum (Pallas 1772) (N=699) and/or Ixodes auritulus Neumann, 1904 (N=18) ticks. Questing A. aureolatum nymphs (N=2) and adults (N=5) were also collected from the soil and the vegetation. None of the I. auritulus were collected off-host. We collected only immatures of A. aureolatum on birds, but all life stages of I. auritulus. The latter species was collected on Turdus rufiventris and on Synallaxis ruficapilla, which is herein recognized as a host of I. auritulus for the first time. Moreover, this is also the first report of A. aureolatum infesting birds, and 16 different bird species were found infested. It was observed that larval infestation was positively correlated with the dry and cold season, while nymphal infestation was positively correlated with the warm and rainy season. Although only 2-years worth of data is provided, our results suggest the infestation of birds by ticks was significantly higher at the biotopes formed by forest at its first stage of regeneration 'capoeira' and the original Araucaria forest habitat 'mata' than the ecotone between forest and urban areas 'peripheral area'.  相似文献   

4.
5.
SUMMARY. Unpigmented nymphs and adults of the corixid bugs Sigara dorsalis and Corixa punctata were found in ponds treated with the aquatic herbicide dichlobenil. Tissue residues accumulated rapidly in nymphs exposed to dichlobenil, and pigmentation was inhibited during ecdysis. However, dichlobenil residues were rapidly eliminated from the tissues of unpigmented nymphs placed into clean water, and pigmentation returned during the following ecdysis.  相似文献   

6.
温度对三叶草彩斑蚜种群参数的影响   总被引:1,自引:1,他引:0  
为了探讨温度对三叶草彩斑蚜种群增长的影响,在实验室研究了15~35℃范围内共9个温度下三叶草彩斑蚜的发育、繁殖和生命表.结果表明:三叶草彩斑蚜种群在35℃下不能存活.若虫的发育历期随着温度的上升而显著缩短,在15 ~ 32℃内为18.33~4.02 d,存活率在40.0%~83.6%,25℃下若虫的存活率最高、32℃下存活率最低.成蚜的平均寿命在10.64 ~ 20.87 d,23℃下寿命最长、32℃下最短.产蚜高峰期随温度的上升而提前,除15℃为15 d以外,其余温度下均在3~6d.平均繁殖力和单头最高繁殖力以25℃下最高,分别为82.0和149.0头.平均世代周期随着温度的上升从15℃的31.17 d逐渐缩短到32℃的10.17 d.净增殖率在25℃下最大(68.62),32℃下最小(13.96).内禀增长率在0.10 ~0.30 d-1,其中28 ℃下最高、15℃下最低.若虫的发育起点温度和有效积温分别为9.35℃和97.83 d·℃.繁殖力、净增殖率和内禀增长率与温度的关系均可用一元二次方程描述.  相似文献   

7.
The Karoo Paralysis tick, Ixodes rubicundus Neumann (Acari: Ixodidae), is a semi-voltine ixodid that survives stressful environmental conditions using morphogenetic diapause (eggs and engorged nymphs) and desiccation resistance. Both photoperiod and temperature influence diapause induction in the engorged nymph. Ixodes rubicundus nymphs are typical long-day photoperiodic organisms. The critical photoperiod is approximately 13.5 h light, 10.5 h dark, and they display a thermolabile response. The period between detachment and apolysis in engorged nymphs is modified by photoperiod; however, apolysis to ecdysis is not affected by photoperiod. Thus, initiation of development, but not the actual process is controlled by photoperiod. Most engorged nymphs delayed metamorphosis when exposed to short-day regimen (LD 12 : 12 h) after feeding. Nymphs exposed to pre- and post-feeding long-day regimen (LD 14 : 10 h) developed. Times for 50% of nymphs to apolyse when exposed to photoperiods of LD 14 : 10 h, 13.5 : 10.5 h, 13 : 11 h and 12 : 12 h were 28, 36, 40 and 58 days, respectively. Times for 50% of engorged nymphs to ecdyse ranged from 38 to 40 days after apolysis. Nymphs were sensitive to photoperiodic exposures before, during and after feeding. Nymphs exposed to long day (LD 14 :10 h) before and during feeding, moulted at 20 degrees C; however, most exposed to 10 degrees C followed by 20 degrees C (post-feeding) went into diapause. Both short- (10 : 14 h) and long- (14 : 10 h) day exposed engorged nymphs survived 45 days at 0% r.h. (n = 73), but diapause-destined ticks kept at 13 degrees C lost the least mass (29.5+/-9.5%, SD), while nondiapause ticks at 23 degrees C lost the most (48.7+/-8.2%, SD). Termination of diapause and transition to development probably coincides with a definite increase of water vapour uptake by engorged nymphs. Comparatively, I. rubicundus engorged nymphs are more desiccation tolerant than a North-American counterpart, Amblyomma cajennense (Fabricius) (Acari: Ixodidae), which is also semi-arid- to xeric-adapted. Diapause conveys important survival attributes that enable engorged I. rubicundus nymphs to inhabit a semi-arid environment with great temperature extremes, and to synchronize their activity periods with seasons and host utilization patterns.  相似文献   

8.
Off-host survival of the northern fowl mite, Ornithonyssus sylviarum (Canestrini & Fanzago) (Acari: Macronyssidae), and the chicken body louse, Menacanthus stramineus (Nitzsch) (Phthiraptera: Menoponidae), was studied at 12 combinations of temperature (15, 21, 27, and 33 degrees C) and humidity (31, 65, and 85% RH). Mite protonymphs and louse third instars survived longer on average than the respective adult stages. Higher temperatures significantly reduced survival of adult and immature stages of both ectoparasites, whereas relative humidity had significant effects on O. sylviarum (especially protonymphs) but not M. stramineus. The LT50 values for adult northern fowl mites ranged from 1.9 (at 33 degrees C, 31%RH) to 8.3 d (at 15 degrees C, 85%RH), LT50 values for mite protonymphs ranged from 2.0 (at 33 degrees C, 31%RH) to 18.1 d (at 15 degrees C, 85%RH), LT50 values for adult lice ranged from 0.5 (at 33 degrees C, 31%RH) to 1.7 d (at 15 degrees C, 65%RH), and LT50 values for nymphal lice ranged from 1.2 (at 33 degrees C, 65%RH) to 3.3 d (at 21 degrees C, 31%RH). Maximum survival of the northern fowl mite was up to 35 d for adults and 29 d for protonymphs. Maximum survival for the chicken body louse was 3.3 d for adults and 5.8 d for nymphs. The data provide minimum guidelines for leaving poultry houses vacant long enough to allow ectoparasites to die before introduction of subsequent new flocks.  相似文献   

9.
The female Blattella germanica pushes out an oötheca 11 days after adult ecdysis and carries it for about 25 days until nymphs hatch out. The terminal oöcyte begins to accumulate yolk abruptly 4 or 5 days after adult ecdysis and grows fully on day 10 when its volume reaches 180 times as compared to that at adult ecdysis.
Vitellogenin, the vitellogenic female-specific protein, was identified by immunoelectrophoresis and Ouchterlony's test. Fluctuation of vitellogenin in the blood, ovary and embryo at various stages was analyzed. Vitellogenin appears in the female blood 3 or 4 days after adult ecdysis and disappears soon after terminal oöcytes have been released to an oötheca. In the ovary, it appears 4 or 5 days after adult ecdysis and disappears when terminal oöcytes leave the ovary. It remains in embryos until shortly before hatching, but is absent in newly hatched nymphs.  相似文献   

10.
The life cycle of Ixodes rubicundus, the Karoo paralysis tick, was studied under field conditions in the south-western Orange Free State, South Africa, by placing freshly engorged ticks in small containers. The life cycle extends over 2 years. The two regulating phases in the life cycle, which undergo a morphogenetic diapause during the hot and dry summer months, are the egg and engorged nymph. Possible behavioural diapause in adults which suppresses questing activity before the end of March. can also serve as a third regulating phase. Temperature affects the duration of the pre-oviposition period of engorged females and the period between detachment of engorged larvae from hosts and ecdysis. Commencement of larval hatch is reasonably synchronized, irrespective of the month during which oviposition occurred. Peak activity periods of larvae (April or May) occur during a period of high rainfall and decreasing daily maximum temperatures. The period between detachment of engorged nymphs from hosts and ecdysis is highly variable (8–36 weeks). All developmental stages of the tick occur mainly during autumn and winter and no ticks are active during the hot summer months of December to February. Larvae, nymphs and adults each survive for only one season.  相似文献   

11.
The life cycle and behavior of Amblyomma rotundatum were evaluated under laboratory conditions. The experiment started with four engorged females collected from toads (Rhinella schneideri) naturally infested at the Pirapitinga Ecological Station in the state of Minas Gerais, Brazil. Developmental periods of free-living stages were assessed in an incubator at 27 ± 1 °C, >80 % RH and darkness. The complete life cycle, including pre-attachment periods for each parasitic stage, ranged from 126 to 228 days. The pre-attachment, feeding and molting periods increased as the life cycle progressed from larva to adult female. Oviposition lasted about 20 days, with the peak occurring on days 4 and 5. Longevity of nymphs and adult females was quite similar (approximately 250 and 240 days, respectively) and slightly longer than that of larvae. Lesions caused by tick feeding are discussed and a list of known hosts, including new host records for A. rotundatum, is offered.  相似文献   

12.
Rhipicephalus haemaphysaloides Supino, 1897 (Ixodida: Ixodidae) is a three‐host hard tick widely distributed in Sri Lanka. The lifecycle of the R. haemaphysaloides population in Sri Lanka was studied under laboratory conditions using fully engorged females collected from dogs. Larvae, nymphs and adults were reared on New Zealand rabbits. Engorged females weighed a mean ± standard deviation (SD) of 470.1 ± 106.5 mg and laid a mean ± SD of 4067.4 ± 3136.2 eggs within 16.1 ± 3.7 days. The mean ± SD preoviposition period was 6.5 ± 1.1 days. The mean ± SD reproductive efficiency index was 8.5 ± 4.1, and was higher in heavier females (Pearson correlation, r = 0.8; P = 0.001). The incubation period of eggs was shorter at higher temperatures. The majority (86.9%) of larvae successfully moulted after a mean ± SD premoulting period of 7.9 ± 0.7 days following a parasitic period of 3.2 ± 0.5 days. Unfed larvae survived a mean ± SD of 103.4 ± 19.8 days. Nymphs completed the bloodmeal after 3.7 ± 0.9 days, weighed 5.7 ± 1.7 mg and demonstrated a premoulting period of 15.1 ± 1.9 days. Unfed nymphs survived a mean ± SD of 45.8 ± 3.8 days. Heavier nymphs moulted into females, whereas lighter nymphs moulted into males (two‐sample t‐test, P < 0.001). The bodyweight of adult females increased more than 100‐fold after feeding. The lifecycle of R. haemaphysaloides was successfully completed on rabbits within a mean of 91.3 days (range: 69–117 days) under laboratory conditions.  相似文献   

13.
The effect of temperature on activity of insecticides for controlling grasshoppers in leafy green vegetables was evaluated. Insecticides evaluated had differing modes of action and included diflubenzuron, azadirachtin, Beauveria bassiana, spinosad, endosulfan, esfenvalerate, and naled. We evaluated these insecticides for efficacy to third instars of differential grasshopper, Melanoplus differentialis (Thomas), at temperatures ranging from 10 to 35 degrees C. In the laboratory, treatment with esfenvalerate resulted in 100% mortality at temperatures of 10 to 35 degrees C, and efficacy was not temperature dependent. Treatment with spinosad resulted in similar mortality as with esfenvalerate at all temperatures except 10 degrees C. The activity of B. bassiana was greatest at 25 degrees C and was adversely affected by high and low temperatures. Treatment with diflubenzuron resulted in increased mortality at high temperatures, and at 35 degrees C its activity was similar to that of esfenvalerate and spinosad. The activity of azadirachtin ranged from 19 to 31% and was not influenced by temperature. In field studies, spinosad, diflubenzuron, and esfenvalerate provided differing levels of mortality both at application and when nymphs were exposed to 1-h-old residues. However, only spinosad and diflubenzuron provided similar levels of mortality when nymphs were exposed to 24-h-old residues. The residual activity of endosulfan, naled, esfenvalerate, and spinosad decreased with increasing time (0-24 h) after exposure to sunlight and high summer temperatures. Compared with other insecticides, naled had a short residual activity period and activity was dependent upon immediate contact with the nymphs or their substrate. B. bassiana was inactive under high temperatures and intense sunlight as occurs in summer.  相似文献   

14.
[目的]褐带蚜小蜂Aphelinus maculatus是近几年发现的棉蚜Aphis gossypii重要寄生蜂之一.目前关于该寄生蜂生物学特性包括行为习性方面的研究非常少.为有效挖掘利用褐带蚜小蜂,对其成虫生物学特性进行了研究.[方法]在室内采取体视显微镜下观察和记录褐带蚜小蜂的羽化节律、交配行为、交配各阶段持续时间...  相似文献   

15.
Twenty-one coccidia-free dogs were fed either experimentally infected or naturally infected beef in 4 experiments. The pretreatment period ranged from days 9 to 33; 7 dogs shed their first sporocysts on day 12. The full length of the patent period was not determined because most dogs were still shedding sporocysts when experiments ended on days 40 and 60. Although the patent period was long, sporocysts were not shed continuously; the total number of days sporocysts were actually shed ranged from 3 to 40. The average number of sporocysts shed by dogs fed 454 to 908 g of beef ranged from 861,000 to over 20 million. Most sporocysts were shed from days 15 to 30; peak numbers were shed on days 23 and 24. Average peak numbers ranged from 145,000 to 408,400 sporocysts. Such data can be applied to facilitate collection of sporocysts in the laboratory or to estimate the potential for transmission of infective organisms under field conditions.  相似文献   

16.
Tetraphleps galchanoides Ghauri (Hemiptera: Anthocoridae) nymphs were collected from hemlock woolly adelgid (HWA) Adelges tsugae Annand (Hemiptera: Adelgidae) infested Tsuga sp. in Baoxing, Sichuan, China. First and second stage nymphs collected from foliage shipped from China; were reared to adults and tested for feeding rates and host preferences. They were reared at 5, 8, 12, and 15 ± 1 °C from November to December, January to March, April, and May to June, respectively, in the quarantine laboratory at Virginia Polytechnic Institute and State University. At 8 °C, development time was 15, 20, and 40 days for the N-III, IV, and V nymphal stages, respectively. Adult males lived 83 days with a range of 21–147 days. A single adult female lived for 21 days. At 5 °C, second stage T. galchanoides nymphs consumed 0.8 HWA nymphs per day, and 2.0 HWA nymphs per day at the N-V stage. At 8 °C, consumption of HWA nymphs ranged from 1.3 to 3.4 nymphs per day for the N-III to N-V stages, respectively. Adult T. galchanoides consumed more HWA eggs than HWA adults, pine bark adelgid (PBA) Pineus strobi (Hartig) (Hemiptera: Adelgidae) adults, and eggs in no-choice tests. In choice tests with HWA eggs and PBA eggs, more HWA eggs were eaten. Adult and nymph body measurements are presented for determination of nymphal instars.  相似文献   

17.
We report biological data of two generations of Amblyomma triste in laboratory and compared the suitability of different host species. Infestations by larval and nymphal stages were performed on guinea pigs (Cavia porcellus), chickens (Gallus gallus), rats (Rattus norvegicus), rabbits (Oryctolagus cuniculus), wild mice (Calomys callosus), dogs (Canis familiaris) and capybaras (Hydrochaeris hydrochaeris). Infestations by adult ticks were performed on dogs, capybaras and rabbits. Tick developmental periods were observed in an incubator at 27 °C and RH 90%. Guinea pigs were the most suitable hosts for larvae and nymphs, followed by chickens. The remaining host species were less suitable for immature ticks as fewer engorged ticks were recovered from them. Mean larval feeding periods varied from 3.8 to 4.7 d between different host species. Mean larval premolt periods ranged from 8.9 to 10.4 d. Nymphal mean feeding periods varied from 4.2 to 6.2 d for ticks fed on different host species. Premolt period of male nymphs (mean: 15.4 d) was significantly longer than that of female nymphs (14.7 d). Female nymphs were significantly heavier than male nymphs. The overall sex ratio of the adult ticks emerged from nymphs was 0.9:1 (M:F). Capybaras were the most suitable host for the tick adult stage as significantly more engorged females were recovered from them and these females were significantly heavier than those recovered from dogs or rabbits. The life cycle of A. triste in laboratory could be completed in an average period of 155 d. The potential role of guinea pigs, birds and capybaras, as hosts for A. triste in nature, is discussed. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

18.
The tortoise tick Hyalomma aegyptium has a typical three-host life-cycle. Whereas its larvae and nymphs are less host-specific feeding on a variety of tetrapods, tortoises of the genus Testudo are principal hosts of adults. Ticks retained this trait also in our study under laboratory conditions, while adults were reluctant to feed on mammalian hosts. Combination of feeding larvae and nymphs on guinea pigs and feeding of adults on Testudo marginata tortoises provided the best results. Feeding period of females was on average 25 days (range 17–44), whereas males remain after female engorgement on tortoise host. Female pre-oviposition period was 14 days (3–31), followed by 24 days of oviposition (18–29). Pre-eclosion and eclosion, both together, takes 31 days (21–43). Larvae fed 5 days (3–9), then molted to nymphs after 17 days (12–23). Feeding period of nymphs lasted 7 days (5–10), engorged nymphs molted to adults after 24 days (19–26). Sex ratio of laboratory hatched H. aegyptium was nearly equal (1:1.09). The average weight of engorged female was 0.95 (0.72–1.12) g. The average number of laid eggs was 6,900 (6,524–7,532) per female, it was significantly correlated with weight of engorged female. Only 2.8% of engorged larvae and 1.8% of engorged nymphs remained un-molted and died. Despite the use of natural host species, feeding success of females reached only 45%. The whole life-cycle was completed within 147 days (98–215).  相似文献   

19.
The purpose of this investigation was to evaluate acquisition and inoculation (together, transmission) efficiency of Candidatus Liberibacter asiaticus (Las), the pathogen associated with citrus huanglongbing (HLB) by the Asian citrus psyllid, Diaphorina citri (Kuwayama) (Hemiptera: Psyllidae). In laboratory studies, nymphs reared on Las infected plants were more likely to acquire the bacterium than adults. Acquisition by nymphs ranged from 60 to 100%, whereas acquisition by adults only reached 40% after 5 wk of feeding on Las-infected plants. Similar rates of pathogen acquisition by psyllids after nymphal and adult feeding were observed in the field. Transmission of Las from parent to offspring (transovarial) occurred at a rate of 2-6%. One year after psyllid inoculations, successful transmission by individual D. citri ranged from 4 to 10%, whereas groups of 100 or more D. citri transmitted the pathogen at a rate of approximately 88%. In addition, the proportion of Las-positive adult psyllids, determined using quantitative real-time polymerase chain reaction, decreased over time when held on healthy plants. Due to the low rate of pathogen acquisition and long time period required for successful inoculation by adult D. citri, experiments designed to determine the latent period required for replication and successful inoculation of Las by D. citri did not result in Las-infected plants after >1 yr of incubation after inoculation. Collectively, these results indicate that adult D. citri which acquire the HLB pathogen as adults are poor vectors of the pathogen compared with adults that acquired the pathogen as nymphs.  相似文献   

20.
The sand flea Tunga penetrans is one of the zoonotic agents of tungiasis, a parasitic skin disease of humans and animals. The dog is one of its main reservoirs. This negatively controlled, randomized, double-masked clinical trial evaluated the therapeutic and residual efficacy of fluralaner for treatment of dogs naturally infested with T. penetrans. Sixty-two dogs from an endemically affected community in Brazil were randomly assigned to either receive oral fluralaner (Bravecto chewable tablets) at a dose of 25 to 56 mg fluralaner/kg body weight, or no treatment (31 dogs per group). Dogs were clinically examined using a severity score for acute canine tungiasis (SCADT), parasitological examinations as defined by the Fortaleza classification, and pictures of lesions on days 0 (inclusion and treatment), 7 ± 2, 14 ± 2, 21 ± 2, 28 ± 2, 60 ± 7, 90 ± 7, 120 ± 7 and 150 ± 7. The percentage of parasite-free dogs after treatment was >90% between days 14 and 90 post-treatment with 100% efficacy on study days 21, 28 and 60. Sand flea counts on fluralaner treated dogs were significantly lower (p<0.025) than control dogs on all counts from day 7 to 120. The number of live sand fleas on treated dogs was reduced by > 90% on day 7, > 95% on days 14 and 90, and 100% from day 21 to 60, and with a significant difference between groups from day 7 to 120. From day 7 to day 120, mean SCADT scores were significantly reduced in treated dogs with a mean of 0.10 compared to 1.54 on day 120 in untreated dogs. Therefore, a single oral fluralaner administration is effective for treating and achieving long lasting (> 12 weeks) prevention for tungiasis in dogs.  相似文献   

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