Potential problems with external trailing antennae: antenna migration and ingrowth of epithelial tissue, a case study from a recaptured Chondrostoma nasus

Examination of a nase Chondrostoma nasus , that was carrying an implanted telemetry transmitter for 7 months, showed that the external trailing antenna of the transmitter had migrated c . 3 cm to the posterior edge of the incision. The absorbable sutures were still present, and there was epithelial tissue within the granulation encapsulating the transmitter. This tissue may have grown down from the surface along the antenna providing a potential entryway for pathogens.     

Fine structure of spermatozoa of Chondrostoma nasus and Rutilus meidingerii (Teleostei, Cyprinidae), as revealed by scanning and transmission electron microscopy

Fürböck, S., Patzner, R.A. and Lahnsteiner, F. 2008. Fine structure of spermatozoa of Chondrostoma nasus and Rutilus meidingerii (Teleostei, Cyprinidae), as revealed by scanning and transmission electron microscopy. — Acta Zoologica (Stockholm) 91 : 88–95
The fine structure of spermatozoa of sneep or nase, Chondrostoma nasus , and lake chub, Rutilus meidingerii , was investigated by means of scanning and transmission electron microscopy. The uniflagellate spermatozoa of C. nasus lacked an acrosome. The flagellum contained the conventional nine peripheral doublets and one central pair of microtubules (9 + 2 pattern) and lacked lateral fins. The uniflagellate spermatozoa of R. meidingerii were made up of a head, also without an acrosome. For both species the sperm tail was covered by a plasma membrane. The midpiece of C. nasus contained five or six mitochondria on average, vesicles and glycogen granules, whereas the midpiece of R. meidingerii had seven mitochondria of a spherical or ovoid shape. The centriolar complex was located caudolaterally with respect to the nucleus. In C. nasus , the centrioles were orientated at an angle of 125° to each other, whereas the centrioles of R. meidingerii were at an angle of 110°. The fine structure of C. nasus and R. meidingerii spermatozoa showed species-specific differences in the position of the proximal centriole relative to the distal centriole, the position and number of mitochondria, size of the head and the length of the flagellum. (Correction added on 11 June 2009, after first online publication: The word 'axoneme' was deleted from the sentence 'The flagellum contained the conventional nine peripheral doublets and one central pair of microtubules (9 + 2 pattern) axoneme and lacked lateral fins.')     

Temperature-induced changes of early development and yolk utilization in the African catfish Clarias gariepinus

Artificially fertilized eggs and yolk-sac larvae of a freshwater tropical/subtropical fish Clarias gariepinus receiving no external food were incubated at 22, 25 and 28° C until full yolk resorption. Developmental time, size and matter composition (CHNS-O Analyzer and ashing) were assessed at egg fertilization, hatching and yolk resorption; respiration was measured every 4–5 h. The course of acceleration of C. gariepinus embryonic developmental rate with temperature ( Q_{10 dev}) was compared over the temperature range to those of Cyprinus carpio and Oncorhynchus mykiss ; they differed greatly, but were similar when compared on the basis of effective temperatures specific to each fish. Specific growth rates for energy (88, 150 and 183% per day at 22,25 and 28° C, respectively) as well as the conversion efficiencies of egg energy (64, 71 and 68%, respectively) and protein (71, 78 and 76%, respectively) in C. gariepinus larval tissues were higher than those known for the endogenous feeding period of coldwater and temperate fish species. In C. gariepinus at the end of yolk resorption, the carbon percentage and caloric values of dry weight, size (in terms of dry matter, minerals, protein and energy per larva) and transformation efficiencies were lowest at 22° C, highest at 25° C and had slightly decreased at 28° C. A tentative mechanism which leads to the positive or negative response of body size to temperature over the viable temperature range is defined.     

Development of a bioenergetics model for fish embryos and larvae during the yolk feeding period

A mechanistic model of an energy budget in fish embryos and yolk-sac larvae was developed using data for five freshwater fish species: rainbow trout Oncorhynchus mykiss , nase Chondrostoma nasus , carp Cyprinus carpio , tench Tinca tinca and African catfish Clarias gariepinus , based on the existing models for adult and juvenile fishes. The model simulates changes in the components of the budget under various conditions. Besides the effects of body mass and temperature on consumption and metabolic rate, the dependence of ration size on amount of available yolk and initial egg size was implemented in the model. The model parameters were found through optimization. A sensitivity analysis of the model was conducted by varying its parameters and observing changes in the output. A comparative analysis showed that the values generated by the model closely approximated independent empirical observations. Simulations of energy budgets demonstrated that the overall pattern of energy partitioning was the same for different species, irrespective of egg size and temperature preferences. Most energy was allocated to body growth. Clarias gariepinus showed the fastest growth and had the highest yolk conversion efficiency.     

温度对大猿叶虫发育、存活和繁殖的影响

在光周期14L:10D、75%RH的条件下研究不同温度对大猿叶虫Colaphellus bowringi Baly生长发育、存活率和繁殖的影响。结果表明,卵、幼虫和蛹的发育起点温度分别为11·86,11·17和10·15℃,有效积温分别为61·6,110·8和65·3日·度;22℃时卵的孵化率和蛹的羽化率最高,分别达96·04%和94·26%;滞育后成虫寿命雌虫普遍长于雄虫,25℃下的产卵期11～34d,每雌产卵量平均861粒,最高达1527粒。     

SEM images reveal intraspecific differences in egg surface properties of common nase (Chondrostoma nasus L.)

Scanning electron microscopy (SEM) has been widely used to describe interspecific differences in egg quality of teleost freshwater fish, but potential intraspecific differences are poorly studied. Eggs of many rheophilic cyprinids are covered with adhesive structures such as attaching villi facilitating egg attachment at substrates of spawning grounds with high currents. Recent findings indicate that the egg quality of the rheophilic cyprinid common nase (Chondrostoma nasus L.), a target species of conservation, differs in the adhesiveness between spawning populations, potentially explaining differences in recruitment success. In this study, a SEM image-based standardized protocol was established to assess egg surface quality of Chondrostoma nasus eggs. Multivariate statistics detected significant differences of egg surface properties among individual females and among three different populations. These differences were mainly attributed to length variability and merging of adhesive villi as well as to coating and filament-like connections of these structures. The findings of this study highlight the need for further investigations to better understand the relationship of egg surface properties, egg stickiness and hatching success to understand the recruitment ecology and performance of early life stages in freshwater fish.     

Effects of temperature on developmental performance, survival and growth of sea lamprey embryos

This study assesses the influence of thermal regime on the development, survival rates and early growth of embryos of sea lamprey Petromyzon marinus incubated at five constant temperatures (7, 11, 15, 19 and 23° C). The time from fertilization to 50% hatching and from hatching to 50% burrowing were inversely related to incubation temperature. All the embryos incubated at 7° C died at very early stages, while those maintained at 11° C did not attain the burrowing stage. Survival from fertilization to hatching was 61, 89, 91 and 89% at 11, 15, 19 and 23° C, decreasing to 58, 70 and 70% from hatching to burrowing at 15, 19 and 23° C, respectively. Larvae reared during the first 3 months of exogenous feeding in a common environment at constant 21° C, revealed maximum survival for an incubation temperature of 15° C (43% of burrowed larvae) decreasing strongly at 19° C (16%) and 23° C (one suvivor among 240 larvae). Body length at the burrowing stage was maximum for embryos incubated at 19° C, but body mass increased in the interval 15–23° C. Mean incubation temperatures experienced by 117 broods during the embryonic development in the source river were estimated in 15·3±2·30° C and 16·7±1·76° C (mean±1 s.d .) for the periods fertilization-to-hatching and hatching-to burrowing, respectively.     

温度对海洋底栖端足类日本大螯蜚(Grandi-dierella japonica)存活、生长和发育的影响

日本大螯蜚（ Ｇｒａｎｄｉｄｉｅｒｅｌｌａ ｊａｐ ｏｎｉｃａ）生长发育的适温范围为 ２０～２６℃。不同发育期耐受温度范围不同,刚孵化幼体温度下限为１１℃,上限为３２℃,以后随着幼体发育,其对低温的适应力逐渐增强。雄性个体对极限温度的忍耐力低于雌性。在耐受温度范围内,幼体的生长发育随着温度的提高而加快。研究结果表明,日本大螯蜚实验室培养温度宜选择在２０～２６℃,用其进行的沉积物急性和慢性毒性生物检验的实验温度均宜选择在 ２０℃。     

Early Development of the Sofie, Chondrostoma toxostoma

The developmental biology of embryos, larvae and juveniles of sofie, Chondrostoma toxostoma, reared from artificial insemination, was examined under controlled laboratory conditions, using both in-vivo and preserved specimens. The complete remodelling process (metamorphosis) was described and interpreted according to the theory of saltatory ontogeny, providing a model within which the highly complex ecological niche and behaviour (habitat use, diet, etc.) of the free embryos and larvae can be evaluated. The sofie ova were relatively opaque and the free embryos presented a small yolksac. Consequently, the free embryo steps were short and the free embryos emerged rapidly from the substratum. The circulatory system appeared early and was simple, which suggests that sofie free embryos require well oxygenated water. The remodelling of the mouth from a superior to inferior position characterised changes in the sofie's diet during early life history, which is typical of the genus. Differences in development relative to the nase, C. naus, are discussed.     

Genetic variability in Chondrostoma from Austrian, French and Greek rivers (Teleostei, Cyprinidae)

Allozyme variation in Chondrostoma from Austrian, French and northern Greek rivers was investigated. Populations of C. nasus from the upper Danube catchment are genetically very similar and apparently connected by high level of gene flow. Chondrostoma nasus has conserved all major allozyme polymorphisms during its recent range expansion into the Rhone basin. Chondrostoma vardarense from the Axios and Aliakmonas rivers share most of their allozymes with C. nasus from the upper Danube catchment, but have less genetic variation, a possible consequence of a genetic bottleneck following river capture.     

洄游型、淡水型和陆封型刀鲚的寄生蠕虫群落结构

由于对淡水环境的适应和江湖阻隔,部分洄游型刀鲚(Coilia nasus)分化成淡水型和陆封型,为寻找区分洄游型、淡水型和陆封型这3种生态型刀鲚的寄生虫标志,并分析其寄生蠕虫群落结构特征,本文调查了3种生态型刀鲚鳃部、胃、肠和幽门盲囊中寄生蠕虫的种类和感染情况。共发现10种寄生虫,包括鳃上3种单殖吸虫:林氏异钩铗虫(Heteromazocraes lingmueni)、细长嗜鳀虫(Helciferus tenuis)和长江中华钩铗虫(Sinomazocraes changjiangensis);胃部1种复殖吸虫:鲚套茎吸虫(Elytrophallus coiliae);肠道3种线虫:简单异尖线虫(Anisakis simplex)、对盲囊线虫(Contracaecum sp.)和胃瘤线虫(Eustrongylides sp.),以及肠和幽门盲囊的3种棘头虫:陈氏刺棘虫(Acanthosentis cheni)、鲇异吻钩棘头虫(Arhythmacanthus parasiluri)、长江傲刺棘头虫(Brentisentis yangtzensis)。林氏异钩铗虫和陈氏刺棘虫在3种生态型的刀鲚中都有较高的感染率和平均丰度;海水性寄生虫细长嗜鳀虫、鲚套茎吸虫和对盲囊线虫只感染洄游型刀鲚,可作为区分洄游型刀鲚的寄生虫标志;淡水性寄生虫长江中华钩铗虫、鲇异吻钩棘头虫和长江傲刺棘头虫只在淡水型刀鲚中发现,可作为淡水型刀鲚的寄生虫标志。洄游型刀鲚的物种丰富度和Brillouin多样性最高,分别在1.25和0.19以上,淡水型刀鲚的较低,分别为0.79~1.12和0.10~0.12,陆封型刀鲚的最低,分别在0.66和0.02以下,这主要是由于淡水型和陆封型刀鲚中海水性寄生虫大部分丢失,以及淡水性寄生虫感染率和平均丰度都较低造成的。盐度降低和中间宿主缺乏是导致淡水型和陆封型刀鲚中海水性寄生虫丢失的主要原因;而淡水性寄生虫较低的感染水平可能是由于其对新宿主的适应时间较短;地理隔离可能是陆封型刀鲚中寄生虫群落多样性最低的另一重要原因。     

温度对中华虎凤蝶幼虫生存与生长发育的影响

本文就温度对中华虎凤蝶幼虫的生存与生长发育进行了研究。结果表明,１龄幼虫１６～３２℃范围内的死亡率无显著差异;２龄幼虫死亡率在３２℃下达３０．９２％,显著高于其它温度;３～５龄幼虫３２℃下全部死亡,其它温度下多以２８℃为高。１～２龄幼虫在１６～３２℃和３～５龄幼虫在１６～２８℃范围内的发育历期随温度升高而显著缩短,而平均发育速率则反之。用Ｗｅｉｂｕｌｌ分布函数能较好地拟合各龄幼虫的存活率曲线,并由此判断出各存活率曲线类型。此外,还测定了各龄幼虫的发育起点温度和有效积温。最后建议中华虎凤蝶１～２龄和３～５龄幼虫饲养适宜温度分别为２８℃和２０～２４℃。     

The effect of temperature on the growth,development and survival of Macropetasma africanus (Balss) (Penaeoidea:Penaeidae) larvae reared in the laboratory

Macropetasma africanus (Balss) has been successfully spawned and its larvae reared under controlled laboratory conditions. The relationship between egg number (E) and female total length (L) was E = 18.59 L^2.11. An experiment was designed to test the effect of temperature on larval development, survival and growth. Temperature effected larval development time, from 13–15 days at 25°C, to 25 days at 15°C (nauplius 1 to post-larva). Mortality was low for the naupliar stages at 25, 22 and 18°C, while at 15°C only 52% of the larvae reached nauplius 6. Mortality was highest from nauplius 6 to protozoea 1 (17, 21, and 18% at 25, 22, and 18°C, respectively), but decreased considerably for all temperatures once the mysis stage was reached. Overall survival rates from nauplius 1 to post-larva decreased with decreasing temperature (65, 54, 48, and 39% at 25, 22, 18, and 15°C respectively). Temperature also significantly affected larval growth. At 25°C mean total length was significantly (P < 0.05) larger than at 15°C (protozoea 2 to post-larva), while from protozoea 3 to post-larva total length differences were significantly different (P < 0.05) between 18 and 25°C. M. africanus has a major spawning peak in summer, suggesting that there may be a selective advantage to reproducing during the warmer months.     

温度对取食芦笋蓟马的巴氏钝绥螨生长发育、存活和繁殖的影响

观察了巴氏钝绥螨Amblyseius barkeri Hughes在5种温度(15、20、25、30和35℃)、食料为芦笋蓟马,相对湿度72%,L∶D=12∶12条件下的发育历期、存活率和繁殖力。结果表明:巴氏钝绥螨卵、幼螨、前若螨、后若螨及世代发育历期在15℃下最长,随着温度的升高而缩短,35℃下最短。产卵前期在15～30℃下,随温度的上升而缩短,35℃下稍有延长。存活率15℃下最低,随温度的上升而提高,30℃下最高。产卵量15℃下最少,其次是35℃,20～30℃下产卵量较多。根据实验结果,组建了巴氏钝绥螨以芦笋蓟马为食料在5种不同温度下的实验种群生命表。     

Effect of initial size on daily growth and survival in freshwater Chondrostoma nasus larvae: a field survey

Effects of initial size on the growth and survival of a freshwater fish, Chondrostoma nasus , were tested in a field survey, where individually tagged larvae were introduced into a potential nursery habitat. Characteristics of individual daily growth trajectories were utilized as a basis to explain growth, as well as survival patterns, in relation to ontogeny. Initial size only affected growth rates during the larval phase. Survival patterns could not be explained solely based on size-selective mortality processes because prey–predator interactions played a major role as well. This is confirmed by the Lande–Arnold selection model because directional, as well as stabilizing gradients, showed significant values. Thus, for the 0+ year freshwater fish, inherited size-specific effects were a significant advantage for growth performance and survival in early ontogeny. As fish grew older, however, other effects such as compensatory growth and prey–predator interactions apparently gained in importance.     

Fledgling survival increases with development time and adult survival across north and south temperate zones

Slow life histories are characterized by high adult survival and few offspring, which are thought to allow increased investment per offspring to increase juvenile survival. Consistent with this pattern, south temperate zone birds are commonly longer‐lived and have fewer young than north temperate zone species. However, comparative analyses of juvenile survival, including during the first few weeks of the post‐fledging period when most juvenile mortality occurs, are largely lacking. We combined our measurements of fledgling survival for eight passerines in South Africa with estimates from published studies of 57 north and south temperate zone songbird species to test three predictions: (1) fledgling survival increases with length of development time in the nest; (2) fledgling survival increases with adult survival and reduced brood size controlled for development time; and (3) south temperate zone species, with their higher adult survival and smaller brood sizes, exhibit higher fledgling survival than north temperate zone species controlled for development time. We found that fledgling survival was higher among south temperate zone species and generally increased with development time and adult survival within and between latitudinal regions. Clutch size did not explain additional variation, but was confounded with adult survival. Given the importance of age‐specific mortality to life history evolution, understanding the causes of these geographical patterns of mortality is important.     

Effects of fish farm effluents on egg-to-fry development and survival of brown trout in artificial redds

Egg-to-fry development and survival of brown trout Salmo trutta were compared in two rivers of the Pyrenean piedmont, the Nive d'Arnéguy, with few human activities, and the Nive des Aldudes, with many anthropogenic activities including 11 fish farms and two sewage treatment plants (STPs). Survival was estimated between spawning (early December) and emergence time (early March) by means of capsules, 7 cm³ in volume, filled with green eggs then inserted into the gravel of artificial redds at spawning sites. In the Nive des Aldudes, three sets of conditions were studied: a fish farm near the springs, a fish farm and an STP in a village, and a series of fish farms and an STP in a village. In each situation, two artificial redds were created upstream and two others downstream from the fish farms. In the Nive d'Arnéguy, four sites were equipped: each of the two downstream sites with two artificial redds, and the two upstream sites with one redd. Substratum characteristics (proportion of fine particles) and the quality of surface and interstitial water (oxygen content, ammonia and nitrite nitrogen) were periodically measured. There was no redd substratum difference between sites upstream and downstream of fish farms. Survival to fry emergence was higher in the Nive d'Arnéguy (63·5%) than in the Nive des Aldudes (47·7%). In this latter river, the nitrogen released from the STPs was 0·5% that from fish farms. Fish farming impaired survival close to fish farm effluents (31·6%), as compared to survival upstream (63·6%), and induced a development delay during the yolk-sac fry stage. These differences were mainly linked to a drop in the dissolved oxygen content in interstitial water induced by the nitrogen flow in surface and interstitial waters.     

Effects of temperature on development,survival, longevity,and fecundity of Serangium japonicum (Coleoptera: Coccinellidae), a predator of Bemisia tabaci Gennadius (Homoptera: Aleyrodidae)

In this study, we evaluated the effect of temperature on the development and reproductive biology of Serangium japonicum (Coleoptera: Coccinellidae) at seven constant temperature regimes (17, 20, 23, 26, 29, 32 and 35°C) for its effect as a predator of Bemisia tabaci (Homoptera: Aleyrodidae). Results indicated that the duration of the egg, larval and pupal stages were significantly affected by temperature. The developmental time gradually declined with the increase of temperature from 17 to 29°C, however an extension in the developmental periods was observed in the temperature range of 32 to 35°C. The survival rates of different insect stages were stable at temperatures between 20 and 32°C; however at extreme temperatures of 35°C, a sharp decrease was evident. The highest fecundity of the female (387.2 eggs per female) was recorded at 20°C. Based on these results, life tables of S. japonicum were constructed for temperatures in the range 20–35°C. The maximum reproductive rate (R ₀=279.9) occurred at 26°C. The maximum values for innate capacity for increase (r _m=0.1131) and the finite rate of increase (λ=1.1197) occurred at 29°C. The mean generation time (T) decreased with increased temperature, the longest of which was 76.0 days (at 20°C) and the shortest was 36.6 days (at 32°C). These results offer valuable insight on the importation and establishment of S. japonicum into new environments with diverse temperature regimes.     

Effects of reduced oxygen level on the mortality and hatching rate of Chondrostoma nasus embryos

Exposure of embryos of Chondrostoma nasus to a strongly reduced oxygen content (about 10% of air saturation) enhanced mortality and depressed hatching success. Viable larvae hatched only from the controls and from the group exposed to reduced oxygen during the earliest embryogenesis (from fertilization to gastrula). In the groups exposed from gastrula to eyed stage and from eyed stage to hatching, a high percentage of fish hatched, but all were deformed and almost all died during the following 1–5 days. Hatching period was prolonged in the groups exposed to reduced oxygen content. At a spawning area C. nasus had deposited a large portion of eggs in areas of reduced oxygen content. On the other hand, eggs placed at the substratum surface were exposed to high predation pressure from Barbus barbus, Lota lota and ducks ( Anas platyrhynchos ). The trade-off between predation pressure at the substratum surface and reduced oxygen conditions in the interstices resulted in a narrow space for successful development of embryos of this endangered rheophilic fish species under natural conditions.     

Modelling temperature-dependent development and survival of Otiorhynchus sulcatus (Coleoptera: Curculionidae)

Abstract 1 We conducted a laboratory experiment to quantify the stage‐specific effects of temperature on development time and survival of Otiorhynchus sulcatus (Fabricius) (Coleoptera: Curculionidae), a serious economic pest of horticultural crops. Quantification of the relationship between stage development and temperature is required to predict seasonal occurrence of particular life stages and to optimize the timing of monitoring and control tactics. 2 Temperature‐dependent survival rate was quantified using an extreme value function and showed a skewed bell shape, due to the vulnerability of the insect to high temperature in all stages. 3 The development times of O. sulcatus decreased with increasing temperature up to 27 °C for eggs and 24 °C for larvae and pupae. The nonlinear relationship between development rate and temperature was described using the Logan model, and enabled us to estimate the optimum temperature for development. 4 The inherent variation of development time was estimated from the cumulative frequency of stage emergence, which was modelled using the cumulative Weibull function. 5 The stage emergence model, which simulated the transition from one stage to the next in relation to temperature and cohort age, was constructed by incorporating stage‐specific survival and development rate submodels with the Weibull model of stage frequency. 6 Our results show a difference in optimal temperature regime among developmental stages of O. sulcatus.