Manifestations of immunity in sheep repeatedly infested with Amblyomma americanum ticks

Three sheep were infested 4 times with 100 Amblyomma americanum tick pairs and kept indoors until the natural termination of the infestations. Characteristics of the tick populations that show efficiency of feeding, fertility, and offspring development, and ELISA antibodies to tick salivary gland extracts were studied at each infestation. On average, female ticks fed on tick-naive sheep detached at 12.1 +/- 0.2 (mean +/- standard error) days, weighed 492 +/- 16.8 mg, engorged 40.7 mg per day, and 35% survived to detachment during the first infestation. During the fourth infestation, they detached at 17.3 +/- 0.8 days, weighed 321 +/- 14.4 mg, engorged 18.8 mg per day on average, and 23% survived to detachment. On average, oviposition of female ticks fed on tick-naive sheep started at 11.8 +/- 0.6 days of detachment, the egg mass weighed 236 +/- 13.2 mg, 43% of the female weight turned into eggs, and 89% of the ticks that detached survived to oviposition during the first infestation. During the fourth infestation, oviposition started at 15.1 +/- 0.5 days, the eggs weighed 103 +/- 9.9 mg, 13% of the tick weight became eggs, and 67% of the ticks survived to oviposition. On average, eclosion started at 35.4 +/- 0.9 days of oviposition and 83% of the egg batches hatched in the first infestation. During the fourth infestation, eclosion started on day 34.9 +/- 0.7, and 47% of the egg batches hatched. Anti-tick resistance was expressed as an inhibition of feeding, fertility, and offspring development.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of temperature on fecundity in vitro, egg hatching and reproductive development of Benedenia seriolae and Zeuxapta seriolae (Monogenea) parasitic on yellowtail kingfish Seriola lalandi

Globally, aquaculture industries involved with commercial culture of kingfish (Seriola spp.) experience outbreaks of monogenean parasites, which can cause heavy stock losses. In Australia and New Zealand, aquaculturists of kingfish Seriola lalandi incur financial losses caused by two monogenean species: Benedenia seriolae and Zeuxapta seriolae which parasitise the skin and gills, respectively. This study provides information on some basic temperature-dependent life-cycle parameters of these problematic monogeneans on S. lalandi. Hatching times and age at maturity were inversely related to water temperature within the range experienced by wild kingfish in New Zealand (13-21 degrees C). Mature B. seriolae in vitro laid on average 37 eggs/day that hatched over approximately 4 days; peak hatching occurred 9, 11 and 22 days post-deposition at temperatures of 21, 17.5 and 13+/-1.0 degrees C, respectively. Z. seriolae in vitro laid on average 246 eggs/day that hatched over 2 days; peak hatching occurred 7, 9 and 15 days post-deposition at these respective temperatures. B. seriolae matured within 20, 25 and 48 days p.i. at 21, 18 and 13 degrees C. Z. seriolae matured within 25, 37 and >52 days p.i. at the same temperatures. This research describes stages in the reproductive development of B. seriolae and Z. seriolae and discusses the inclusion of basic parasitic life-cycle parameters into management strategies designed to maximise treatment efficacy and limit monogenean epizootics in sea-cage kingfish culture.     

Anopheles albitarsis embryogenesis: morphological identification of major events

Anopheles albitarsis embryogenesis was analyzed through confocal microscopy of clarified eggs. Using Drosophila melanogaster as reference system, the major morphogenetic events (blastoderm, gastrulation, germ band extension, germ band retraction, dorsal closure) were identified. The kinetics of early events is proportionally similar in both systems, but late movements (from germ band retraction on) progress slower in An. albitarsis. Major differences in An. albitarsis related to D. melanogaster were: (1) pole cells do not protrude from the blastoderm; (2) the mosquito embryo undergoes a 180 degrees rotation movement, along its longitudinal axis; (3) the head remains individualized throughout embryogenesis; (4) extraembryonary membranes surround the whole embryo. A novel kind of malaria control is under development and is based on the use of genetically modified mosquitoes. Phenotypic analysis of the embryonic development of mutants will be imposed as part of the evaluation of effectiveness and risk of employment of this strategy in the field. In order to accomplish this, knowledge of the wild type embryo is a prerequisite. Morphological studies will also serve as basis for subsequent development biology approaches.     

Sprays of emulsifiable Beauveria bassiana formulation are ovicidal towards Tetranychus urticae (Acari: Tetranychidae) at various regimes of temperature and humidity

Aerial conidia of Beauveria bassiana in an emulsifiable formulation germinated by >95% after 24 h exposure to the regimes of 20, 25 and 30 degrees C with 51%, 74% and 95% RH. Ovicidal activities of the formulation towards two-spotted spider mite, Tetranychus urticae, were assayed at the concentrations of 0, 18, 160 and 693 conidia mm(-2) sprayed separately onto fava bean leaves including 39 (25-76) eggs per capita. All the sprayed eggs on the leaves were directly exposed to the different regimes for hatch after 24 h maintenance in covered Petri dishes. Generally, hatched proportions increased over post-spray days and decreased with the elevated fungal concentrations; no more eggs hatched from day 9 or 10 onwards. Based on the counts of the hatched/non-hatched eggs in the different regimes, the final egg mortalities were 15.0-40.4%, 48.9-66.6% and 62.9-87.5% at the low, medium and high concentrations, respectively, but only 5.6-11.3% in blank controls. The RH effect on the fungal action was significant at 20 and 25 degrees C but not at 30 degrees C whereas the effect of temperature was significant at 51% and 74% RH but not at 95% RH. Probit analysis of the egg mortalities versus the fungal sprays generated median lethal concentrations (LC(50)) of 65-320 conidia mm(-2) at all the regimes, and of only 65-78 conidia mm(-2) at 25-30 degrees C with 74-95% RH. The results highlight ovicidal activities of the emulsifiable formulation against the mite species at the tested regimes and its potential use in spider mite control.     

The developmental viability and sizes of sequentially oviposited eggs ofBoophilus decoloratus andBoophilus geigyi

The viability and sizes of eggs sequentially laid up to the 10th day of oviposition by engorgedBoophilus decoloratus andBoophilus geigyi were studied. The average length and breadth of eggs laid on the 1st and 2nd days of oviposition were statistically greater than at subsequent ovipositions. The eclosion periods of eggs laid from 7th to 10th day of oviposition were shorter than those of eggs laid earlier by bothBoophilus species. The percentage mortality of eggs of 9th and 10th day of oviposition was significantly higher than that of the earlier ovipositions. The numbers of larvae which engorged on rabbits after hatching from eggs of 7th–10th day ovipositions were significantly fewer than those which hatched from eggs of earlier ovipositions. It is concluded that eggs of early ovipositions ofB. decoloratus andB. geigyi are more viable and survive longer than those of later ovipositions. It is also suggested that the shorter eclosion period of the eggs of later ovipositions is due to the process of embryogenesis which is gradual in the eggs of early ovipositions and faster in those of later ovipositions.     

Effect of temperature on life history of the predatory mite Amblyseius (Neoseiulus) californicus (Acari: Phytoseiidae)

Amblyseius (Neoseiulus) californicus is an indigenous mite in Japan that feeds on many spider mite species. We evaluated the development, survivorship and life-history parameters of A. californicus on a diet of eggs of Tetranychus urticae (red form). More than 97.3% of A. californicus eggs hatched and more than 81.6% of newly hatched larvae attained maturity at temperatures between 15 and 35 degrees C. Females oviposited at 37.5 degrees C, but no eggs hatched. At 40 degrees C, no females laid eggs. The lower threshold temperature from egg to oviposition was 10.3 degrees C and the thermal constant was 86.2 degree-days. Based on these data, the maximum number of generations that could complete development in a year under field conditions in Ibaraki, central Japan, would be between 21 and 28. At 25 degrees C, females laid a mean of 41.6 eggs during a mean oviposition period of 19.4 days. The intrinsic rates of natural increase (rm) were 0.173 at 20 degrees C, 0.274 at 25 degrees C and 0.340 at 30 degrees C.     

Hypoxic incubation blunts the development of thermogenesis in chicken embryos and hatchlings

We asked to what extent sustained hypoxia during embryonic growth might interfere with the normal development of thermogenesis. White Leghorn chicken eggs were incubated at 38 degrees C either in normoxia (Nx, 21% O2) or in hypoxia [Hx, 15% O2, from embryonic day 5 (E5) until hatching]. The Hx embryos had lower body weight (W) throughout incubation, and hatching was delayed by about 10 h. For both groups, all measurements were conducted in normoxia. At embryonic day E11, the static temperature-oxygen consumption (ambient T-Vo2) curve was typically ectothermic (Q10 = 1.92-1.94) and similar between Nx and Hx. Toward the end of incubation (E20), the Q10 averaged 1.41 +/- 0.06 in Nx and 1.79 +/- 0.08 in Hx (P < 0.005), indicating that the onset of the thermogenic response in Hx lagged behind Nx. In the 1-day-old hatchlings (H1), body weight did not significantly differ between Nx and Hx. At H1, the T-Vo2 curves were endothermic-type, and more so in the older (>8 h old) than in the newly hatched (<8 h old) chicks, whether examined statically or dynamically as a function of time. In either case, the thermogenic responses of Hx were lower than those of Nx. In a 43-31 degrees C thermocline, the preferred T of the Hx hatchlings was around 37.3 degrees C, and similar to Nx, suggesting a similar setpoint for thermoregulation. We conclude that hypoxic incubation blunted the development of thermogenesis. This could be interpreted as an example of epigenetic regulation, in which an environmental perturbation during early development alters the phenotypic expression of a regulatory system.     

Hatching of the winter eggs of the fruit-tree red spider mite (Panonychus ulmi (Koch))

Observations on the hatching of winter eggs of Panonychus ulmi (Koch) from apple orchards in England over the 5 years 1962-6 are described. Differences of 2–3 weeks between orchards in the date at which 50% hatch was reached were quite common and this was out of step with petal fall in the majority of orchards. There was a continuous range between early and late hatching populations and a tendency for the populations to hatch in the same order every year. In 1966 populations on Cox's Orange Pippin hatched earlier than those on Worcester Pearmain but the difference was unlikely to be of practical importance. Neither recording accumulated day degrees for populations hatched out-of-doors nor hatching in an incubator after chilling was considered to give a sufficiently reliable forecast of 50% hatch but observations in 1966 suggested that this might be predicted from the total eggs hatched in an incubator expressed as a percentage of total healthy eggs.     

绿盲蝽成虫的产卵行为与习性

本文观察记录了绿盲蝽Apolygus lucorum(Meyer-Dür)雌性成虫的产卵行为,并研究了其产卵习性。结果发现,绿盲蝽卵主要产在植物组织中,单次产卵平均历时31.4 s;产卵主要在夜间进行,白天的产卵量仅占全天的6.6%。成虫交配后主要产可育卵,后期偶产不育卵;而未交配个体大部分能产不育卵。在25℃下,成虫从7日龄起开始产卵,16日龄前产卵量占总产卵量的48.9%;17～40日龄间产卵量约占40%。在棉株上,约65%卵分布在中部(第4到第7果枝),同时94.3%卵集中在叶柄、叶脉、蕾柄和铃柄上。     

玉带凤蝶羽化时间的控制

对玉带凤蝶卵、蛹在 5～ 8℃下冷藏试验和越冬蛹的加温试验表明 ,已发育 1～ 2d的卵 ,其冷藏时间可达 7d ,孵化率达 93 % ,孵化率随冷藏前发育天数和冷藏天数的增加而降低 ;发育蛹的耐低温能力比卵弱 ,已发育 1d的蛹 ,冷藏 3d后 ,羽化率仅为 80 % ,羽化率随蛹冷藏前的发育天数和冷藏天数的增加而降低 ;越冬蛹加温 ,可促使其提早 2 3的时间羽化     

Life history of hawthorn spider mite Amphitetranychus viennensis (Acarina: Tetranychidae) on various apple cultivars and at different temperatures

Development duration and reproduction rate of hawthorn spider mite Amphitetranychus viennensis (Zacher) were carried out on five different apple cultivars (Amasya (local cultivar), Golden Delicious, Granny Smith, Starking Delicious and Starkrimson Delicious) at 25 degrees C, 65 +/- 10% RH and 16:8 L:D. In addition, the same parameters were determined on Golden Delicious leaves at three constant temperatures (20, 30 and 35 degrees C, 65 +/- 10% RH and 16:8 L:D) in the laboratory. A. viennensis showed a better performance on Golden Delicious than on the other apple cultivars. This was mainly due to a short development time (10.7 days), high daily egg production (5.2 eggs/female/day) and early reproduction peak. The highest intrinsic rate of natural increase (rm) was determined on the variety Golden Delicious (rm = 0.247/day), while the lowest one was observed on the variety Starking Delicious (rm = 0.215/day). The developmental periods of A. viennensis varied from 7.4 to 18.8 days at 35 and 20 degrees C for females, while it varied from 7.9 to 17.2 days at 30 and 20 degrees C for males. The development threshold of the eggs and pre-adult stages were 9.72 and 9.07 degrees C, total effective temperature was 72.99 and 185.18 degree-days, respectively. The mean generation time (To) of the population ranged from 16.13 days at 30 degrees C to 29.15 days at 20 degrees C. The net reproductive rate (R0) increased from 54.33 female/female at 20 degrees C to 78.34 female/female at 25 degrees C, and decreased to 75.71 female/female at 30 degrees C. The highest intrinsic rate of increase (rm) was reached at 30 C (rm = 0.268/day), the lowest one at 20 degrees C (rm = 0.136/day).     

Isoenzymatic variability among five Anopheles species belonging to the Nyssorhynchus and Anopheles subgenera of the Amazon region,Brazil

An isoenzymatic comparative analysis of the variability and genetics differentiation among Anopheles species was done in populations of An. (Nys.) intermedius and An. (Ano.) mattogrossensis of the Anopheles subgenus, and of An. darlingi, An. albitarsis and An. triannulatus of the Nyssorhynchus subgenus, with the aim of detecting differences between both subgenera and of estimating the degree of genetic intere specific divergence. Samples from Macap , State of Amap and Janauari Lake, near Manaus, State of Amazonas, were analyzed for eight isoenzymatic loci. Analysis revealed differences in the average number of alleles per locus (1.6-2.3) and heterozygosity (0.060-0.284). However, the proportion of polymorphic loci was the same for An. (Nys.) darlingi, An. (Nys.) triannulatus and An. (Ano.) mattogrossensis (50%), but differed for An. (Nys.) albitarsis (62.5%) and An. (Ano.) intermedius (25%). Only the IDH1 (P > 0.5) locus in all species studied was in Hardy-Weinberg equilibrium. The fixation index demonstrated elevated genetic structuring among species, based on values of Fst = 0.644 and genetic distance (0.344-0.989). Genetic difference was higher between An. (Nys.) triannulatus and An. (Ano.) intermedius (0.989) and smaller between An. (Nys.) albitarsis sensu lato and An. (Nys.) darlingi (0.344). The data show interspecific genetic divergence which differs from the phylogenetic hypothesis based on morphological characters.     

榆木蠹蛾生物学特性观察

结合田间观察和室内试验,对榆木蠹蛾HolcocerusvicariusWalker的生物学特性进行了较为系统的研究。结果表明,榆木蠹蛾在宁夏3年发生1代,幼虫主要危害枝干和根颈部,幼虫在蛀道内越冬,5月下旬老熟幼虫在被害树周围5—10cm深的沙土内分散化蛹,蛹期（21±5）d。6月初成虫开始出现,有2个羽化高峰,分别为6月中旬和7月下旬,成虫羽化当晚即可交尾,交尾当天或第2天产卵,每雌蛾产卵最多达720粒,卵期（17±5）d,孵化率为72％～88％。未交尾雌雄成虫寿命为5—6d,交尾后雌雄成虫寿命缩短为3—5d。初孵幼虫于6月中旬始见,10月下旬幼虫开始越冬。幼虫孵化后,先危害韧皮部,常10多条聚集在一起,稍大一点即蛀入木质部。本研究为制定切实可行的榆木蠹蛾有效防治提供理论依据。     

中华花翅跳小蜂生物学特性和种群动态的研究

中华花翅跳小蜂Microterys sinicus Jiang是白蜡虫成虫产卵期的主要天敌。该蜂成虫喜在自然光下活动,取食和交配都在寄主树上进行。中华花翅跳小蜂每雌平均怀卵量34.39粒,产卵前期2～3天。产卵量、产卵率和产卵天数与温度密切相关,27℃时产卵量和产卵率最高。30℃时产卵天数最少。21～27℃卵孵化率达80%以上。幼虫共5龄。每头跳小蜂幼虫平均取食蜡虫卵数分别为：1龄14.6粒,2龄29.8粒,3龄69.4粒,4龄126.9粒。5龄幼虫不取食。全代发育起点温度和有效积温分别为11.84℃和574.32日·度。补充营养能显著延长成虫寿命和产卵天数,提高雌虫产卵量。中华花翅跳小蜂成虫在田间有两个高峰期,分别发生在4月上中旬和5月中下旬。每粒虫囊内跳小蜂幼虫数与白蜡虫健卵百分率呈负指数关系,拟合方程为：Y=96.0829Exp(-0.1872x)。     

Hatching rhythms in three species of Diclidophora (Monogenea) with observations on host behaviour.

Eggs of three species of Diclidophora were incubated in alternating 12 h periods of light and darkness at 13 degrees C. Eggs of D. merlangi collected at Arbroath hatched during the illumination period with most larvae being recovered in the first 4-6 h; some evidence of a seasonal difference in hatching of these eggs was found. Eggs of D. merlangi collected at Plymouth hatched with a peak of larval recovery in the 2 h period before the light came on. Eggs of D. luscae hatched over 'dusk' while those of D. denticulata hatched after the light was switched off. Neither mechanical disturbance nor the proximity of host tissue caused hatching in D. merlangi or D. luscae. Observations on the behaviour of the host fishes suggest that the hatching rhythms are adapted to specific host behaviour patterns.     

Protective efficacy of maternal antibodies induced by Salmonella toxoid (vaccine)

An attempt was made to evaluate the protective efficacy of maternal antibodies in chicks against salmonellosis. Layer chicks ageing 21 days were individually vaccinated with 100 microg of Salmonella enterica subspecies enterica serovar Weltevreden (BM 1643) toxoid adjuvanted with vitamin E subcutaneously. After 90 days of the primary vaccination the birds were given booster dose of the vaccine. The saline extract of the yolk of eggs laid by the vaccinated birds yielded agglutination and ELISA titres ranging from 43.2 +/- 5.33 to 75.2 +/- 6.26 and 4.987 x 10(3) +/- 0.54 to 5.89x103 +/- 0.56, respectively. Sera of chicks hatched from eggs laid by the vaccinated layers were also subjected to agglutination and ELISA. Agglutination and ELISA titres on the 5th day--post hatching (dph) were 21.6 +/- 1.75 and 4.025 x 10(2) +/- 0.59, while on the 10th dph titers were 13.6 +/- 1.65 and 1.21 x 10(2) +/- 0.60, respectively. It was also observed that only one out of 6 chicks died when challenged with 2 x 10(9) CFU of S. serovar Gallirarum at the age of 7 days showing 83.33% protection. Thus it can be concluded that passive immunity confided by Salmonella enterica subspecies enterica serovar Weltevreden (BM 1643) toxoid can protect chicks against salmonellosis during their early days of life.     

Carbon dioxide baited trap catches do not correlate with human landing collections of Anopheles aquasalis in Suriname

Three types of carbon dioxide-baited traps, i.e., the Centers for Disease Control Miniature Light Trap without light, the BioGents (BG) Sentinel Mosquito Trap (BG-Sentinel) and the Mosquito Magnet? Liberty Plus were compared with human landing collections in their efficiency in collecting Anopheles (Nyssorhynchus) aquasalis mosquitoes. Of 13,549 total mosquitoes collected, 1,019 (7.52%) were An. aquasalis. Large numbers of Culex spp were also collected, in particular with the (BG-Sentinel). The majority of An. aquasalis (83.8%) were collected by the human landing collection (HLC). None of the trap catches correlated with HLC in the number of An. aquasalis captured over time. The high efficiency of the HLC method indicates that this malaria vector was anthropophilic at this site, especially as carbon dioxide was insufficiently attractive as stand-alone bait. Traps using carbon dioxide in combination with human odorants may provide better results.     

The importance of Anopheles albitarsis E and An. darlingi in human malaria transmission in Boa Vista, state of Roraima, Brazil

In several districts of Boa Vista, state of Roraima, Brazil we found Anopheles (Nyssorhynchus) albitarsis E to be the primary vector of human malaria parasites, and during 2001-2002 it was significantly more abundant than An. darlingi (p < 0.001). Other species sampled were An. (Nys.) braziliensis, An. (Ano.) peryassui, An. (Nys.) nuneztovari, An. (Nys.) oswaldoi s.l., and An. (Nys.) triannulatus. As determined by the ELISA technique An. darlingi had a higher overall infection rate (2.1%) compared with An. albitarsis E (1.2%). However a marginally higher proportion of An. albitarsis E was infected with Plasmodium vivax compared with An. darlingi, and the An. albitarsis E biting index was also much higher These results suggest the importance of An. albitarsis E in malaria transmission in a savannah ecoregion of northern Amazonian Brazil, and reconfirm the importance of An. darlingi even if at lower abundance.     

春尺蠖生物学特性研究

【目的】为新疆北疆地区春尺蠖Apocheima cinerarius预测预报工作提供理论依据。【方法】本文在林间对春尺蠖的各虫态进行详细调查,记述了各虫态的形态特征、生活史、性比、行为与习性。【结果】春尺蠖蛹主要集中分布在树盘基部30~60 cm、土壤深度为20~30 cm范围的土层中,成虫羽化后,次日19:00—23:00或第3天下午4:00—6:00交尾,其交配行为是多次交配型。雌虫比雄虫羽化稍早,雌虫平均寿命为16~18 d,雄虫平均寿命为8~13 d。翌日黄昏开始产卵,卵期最长34 d,最短26 d,雌虫每天平均产卵块数最高达5.1块/头、平均卵粒数为363.1粒/头,最低为1块/头、平均卵粒数为86粒/头,平均孵化率为86%。1、2龄幼虫食叶量较低,3龄开始暴增,5龄最高,平均每日食叶量可达443 mm2/头。【结论】春尺蠖成虫按翅面斑纹和颜色,可分三种类型:深色型、常见型、浅色型。幼虫的头壳与虫龄呈显著直线正相关。幼虫1~2龄期间,死亡率较高,高达60.37%;4~5龄幼虫,死亡率较低,且食叶量占总食叶量的85.81%。所以应选择在3龄幼虫高峰期之前进行防治。雌雄比为1︰0.7068,可预测下一代种群数量呈上升趋势。