The use of morphometric characters to discriminate specimens of laboratory-reared and wild populations of Gyrodactylus salaris and G. thymalli (Monogenea)

Gyrodactylus thymalli Zitnan, 1960 and G. salaris Malmberg, 1957 have an indistinguishable ribosomal internal transcribed spacer (ITS) DNA sequence, but exhibit surprisingly high levels of intra- and interspecific sequence variation of the mitochondrial cytochrome oxidase I (CO1) gene. To test whether different populations of these reportedly very similar species could be discriminated using morphometric methods, we examined the morphometry of four different populations representing different mitochondrial clades. Twenty five point-to-point measurements, including five new characters of the attachment hooks, were recorded from three Norwegian laboratory populations (G. salaris from the Rivers Lierelva and Rauma, and G. thymalli from the River Rena), and from one wild population of G. thymalli from the River Test, UK. The Norwegian populations were kept under identical environmental conditions to control for the influence of temperature on the haptoral attachment hooks. Data were subsequently subjected to univariate and linear stepwise discriminant analyses. The model generated by the linear stepwise discriminant analysis used 18 of the 25 original variables, the first two roots accounting for 96.6% of the total variation between specimens. The hamulus shaft length accounts for 66.7% of the overall correct classification efficiency. Based on morphometry, all specimens were assigned to the correct species. Apart from three specimens of G. salaris from the River Lierelva population which were misclassified as belonging to the G. salaris Rauma population, all specimens were assigned to the correct population. Thus, populations of Gyrodactylus identified by mtDNA can also be discriminated using morphometric landmark distances.     

Chaetotaxy of the monogeneans Macrogyrodactylus clarii and m. congolensis from the gills and skin of the catfish clarias gariepinus in Egypt, with a note on argentophilic elements in the nervous system.

A comparison has been made between the chaetotaxy of the gyrodactylid monogeneans Macrogyrodactylus clarii Gussev, 1961 and M. congolensis (Prudhoe, 1957) Yamaguti, 1963 from the gills and skin, respectively, of the catfish Clarias gariepinus (Burchell) from the river Nile in Egypt. Bilaterally arranged argentophilic structures on the surface of these parasites are presumed to be sensilla and are more abundant in M. clarii than in M. congolensis especially on the ventral surface (124 vs. 66). In both species these sensilla are concentrated on the head lobes and in the pharyngeal region, but there are features of the sensilla patterns that can be used to distinguish the two species. Comparison is made with sensilla patterns of other gyrodactylids. A system of cells and dendritic processes, most probably part of the nervous system, also has an affinity for silver in the two species. There are no previous records of extensive argentophilic elements in the nervous systems of monogeneans.     

南美斑潜蝇触角感器的扫描电镜观察

利用扫描电镜对南美斑潜蝇触角形态和感器进行了观察.结果表明,南美斑潜蝇触角为具芒状,由柄节、梗节、鞭节三部分组成,鞭节上着生触角芒.触角感器有五种,分别为刺形感器、毛形感器、锥形感器、钟形感器和腔锥形感器,所有的触角感器都分布在鞭节上.雌雄成虫在触角形态、感器种类与分布上没有显著性差异.     

金银花尺蠖幼虫头部化学感受器扫描电镜观察

为了解金银花尺蠖Heterolocha jinyinhuaphaga Chu幼虫头部化学感受器的种类、形态、数量和分布,利用扫描电镜技术观察其老熟幼虫头部形态及触角和口器上的化学感受器。结果表明,金银花尺蠖老熟幼虫头部呈椭圆形;触角上着生1个毛形感受器、3个刺形感受器、1个栓锥形感受器和2个锥形感受器;上颚分布有1对毛形感受器;下颚分布有3个毛形感受器、2个刺形感受器、2个栓锥形感受器和8个锥形感受器;下唇须上有1个栓锥形感受器和1个刺形感受器;在吐丝器前方两侧有1对刺形感受器。金银花尺蠖幼虫触角上的化学感受器较少,口器附肢上化学感受器较多。     

红脂大小蠹成虫触角感器的扫描电镜观察

红脂大小蠹Dendroctonus valens LeConte属鞘翅目Coleoptera小蠹科Scolytidae,是我国一种重要的外来入侵害虫。为探究其寄主找寻、配偶找寻和种群聚集等行为机制,本文利用扫描电镜技术,对红脂大小蠹雌雄成虫的触角进行了观察,并对感器进行了分类以及其分布规律的研究。结果表明:红脂大小蠹雌雄成虫触角上共存在包括刺形感器、毛形感器、锥形感器、腔锥形感器和Bhm氏鬃毛在内的5种感器类型,其中毛形感器又分为形态各异的3种亚型。这些感器类型大都在触角的棒节上成带状分布。通过对比其他类似的研究以及感器的外部形态特征,推测红脂大小蠹的毛形感器和锥形感器是化学感受器,是最重要的嗅觉器官;刺形感器、腔锥形感器以及Bhm氏鬃毛是机械感受器,且腔锥形感器可以感受温湿度,Bhm氏鬃毛可以感知触角的位置。研究结果为明确红脂大小蠹的生境选择、种群聚集等行为机制提供了理论基础。     

朱红毛斑蛾幼虫头部感受器扫描电镜观察

为了解朱红毛斑蛾Phauda flammans(Walker)幼虫头部感受器的种类、分布、数量以及形态特征,利用扫描电镜观察了朱红毛斑蛾幼虫头部形态及触角和口器上的感受器。结果表明,朱红毛斑蛾幼虫头部椭球形,下口式;触角上着生2个毛形感受器、1个刺形感受器和3个锥形感受器;上颚分布有1对刺形感受器和2对栓锥形感受器;下颚分布有1对毛形感受器和1对刺形感受器,下颚须分布有8个锥形感受器;下唇须分布有1个锥形感受器和1个刺形感受器。锥形感受器在朱红毛斑蛾幼虫头部上的分布多而广,在寄主选择时可能发挥关键作用。     

Gyrodactylus bohemicus sp. n. (Monogenea: Gyrodactylidae) from Oncorhynchus mykiss (Walbaum) and Salvelinus fontinalis (Mitchill) (Clupeiformes: Salmonidae) in Czechoslovakia.

Gyrodactylus bohemicus sp. n (Gyrodactylidae: Monogenea) is described from the fins, skin and gill filaments of Oncorhynchus mykiss (Walbaum) and Salvelinus fontinalis (Mitchill) (Clupeiformes: Salmonidae) from a trout farm in Czechoslovakia. G. bohemicus sp. n. is most closely related to G. thymalli Zitnan, 1960 and G. magnus Konovalov, 1967 in the shape of the anchors, the ventral and the dorsal bar, but can be distinguished from both these species by the shape of the marginal hook proper.     

双委夜蛾幼虫触角、口器感器的类型与分布

双委夜蛾是近年在中国新发现的一种重要农业害虫。本研究通过扫描电子显微镜对双委夜蛾幼虫口器上的感器类型与分布特征进行观察,并做了详细描述。双委夜蛾幼虫触角感器主要分布在梗节和鞭节。梗节包括3个锥形感器和2个刺形感器。鞭节包括3个锥形感器和1个栓锥形感器。双委夜蛾幼虫口器由上唇、上颚、下颚、舌、下唇五部分组成。上唇有6对刺形感器;内唇有3对刺形感器、1对指形感器和1对内唇感器;每个具齿的上颚外侧表面具有2个刺形感器;下颚的感器主要密布在外颚叶和下颚须上,每个外颚叶具有3个刺形感器、3个锥形感器和2个栓锥形感器;下颚须具有8个锥形感器、1个指形感器和2个板形感器。下唇须具有1个栓锥形感器和1个锥形感器。另外,通过与其他鳞翅目幼虫感器比较,对这些感器的功能进行了分析。本研究将为进一步探讨昆虫的取食机制提供参考依据。     

云南锦斑蛾幼虫触角和口器感器的超微结构

利用扫描电子显微镜技术,研究了云南锦斑蛾幼虫头部触角和口器上的感器.结果 表明,云南锦斑蛾幼虫头部呈椭球形.每根触角上具有1根毛形感器、1根刺形感器、5根锥形感器和1根栓锥形感器.上唇两侧各有6根刺形感器.内唇分布有6根刺形感器、4根内唇感器和2根指形感器.每个上颚表面具有2根刺形感器.下颚的感器主要分布在外颚叶和下颚...     

棉铃虫为害与拟轮生镰孢侵染对玉米穗腐病发生及玉米籽粒中伏马毒素污染水平的影响

本研究以‘浚单20’为供试玉米品种,以棉铃虫为供试昆虫,以拟轮生镰孢为供试病原菌,分别进行单独及复合处理,以明确棉铃虫和拟轮生镰孢单独处理和复合处理对玉米穗腐病发病程度及籽粒中伏马毒素污染水平的影响。结果表明,2011年和2012年均以棉铃虫与拟轮生镰孢侵染复合处理对穗腐病发病程度及籽粒中伏马毒素污染水平的影响最大,穗腐病平均病级分别为0.68±0.05和1.08±0.19;单独接种棉铃虫,2011年和2012年的穗腐病平均病级分别为0.31±0.05和0.71±0.06;单独接种拟轮生镰孢,穗腐病平均病级分别为0.24±0.03和1.05±0.29。复合处理的籽粒中伏马毒素污染水平,2011年和2012年分别为(0.85±0.56)mg/kg和(2.36±0.98)mg/kg;单独接种棉铃虫处理分别为(0.17±0.12)mg/kg和(0.01±0.002)mg/kg;单独接种拟轮生镰孢处理分别为(0.10±0.03)mg/kg和(1.14±0.62)mg/kg。相同处理条件下,降水量大和相对湿度高的气候条件更有利于穗腐病的发生及籽粒中伏马毒素的积累。     

河北昌黎与广西资源两地区葡萄霜霉菌致病力分化分析

为明确河北昌黎、广西资源两地不同葡萄品种来源霜霉菌致病力分化情况,本研究利用离体叶盘接种法测定了河北、广西主栽品种‘红宝石无核’、‘红地球’及‘巨峰’来源葡萄霜霉病菌对不同鉴别寄主的致病力,观察不同地区、不同寄主来源病菌对同一感病材料以及同一寄主来源病菌对不同感病材料的致病力大小是否存在差异。结果表明:不同地区同一寄主来源病菌及同一来源不同菌株间致病力均存在差异,说明两个地区病菌群体间和群体内各菌株间均存在分化;两地不同寄主来源病菌群体对同一感病材料的致病力及同一寄主来源病菌群体对不同感病材料的致病力均存在显著差异,且广西资源地区菌株间差异性比河北昌黎地区更明显,说明不同寄主来源的菌株存在一定程度的分化。     

Homing of Gyrodactylus salaris and G. derjavini (Monogenea) on different hosts and response post-attachment

In natural European waters, the congeneric monogeneans Gyrodactylus derjavini Mikailov, 1975 and G. salaris Malmberg, 1957 are primarily found on brown trout Salmo trutta L. and Atlantic salmon Salmo salar L., respectively. Interestingly, rainbow trout, Oncorhynchus mykiss (Walbaum), originating from North America, is as susceptible as brown trout to G. derjavini. However, the mechanisms involved in this host specificity are poorly understood but may include behavioural, mechanical and chemical factors affecting parasite attraction, attachment, feeding, reproduction and host responses. In the present laboratory work, this question has been studied. Detached parasites (either G. derjavini or G. salaris) were offered a choice in small aquaria between fry of rainbow trout, Atlantic salmon and carp Cyprinus carpio L. Within 48 hours more than 90% of G. derjavini colonised rainbow trout and left salmon almost uninfected. Some parasites were found on carp. During the same time span, more than 60% of G. salaris attached to salmon, the rest infected rainbow trout and none were found on carp. Following attachment, the parasites need appropriate stimuli to initiate feeding and reproduction but even such a successful specific colonisation can be followed by a host response. Both humoral and cellular elements have been suggested to participate in these reactions but in the present work it was demonstrated by immunoblotting and immunocytochemistry that no antibodies in host mucus and host plasma bound to any parasite structures or epitopes.     

柑橘粉虱触角超微结构特征研究

采用扫描电子显微镜对柑橘粉虱(Dialeurodes citri Ashm)雌雄成虫触角进行了观察,研究其触角的超微形态特征.结果表明,雌雄柑橘粉虱触角均为线状,共7节,由柄节、梗节和鞭节(5亚节)组成;触角表面形态变化多样;触角感受器有5种类型,分别为毛形感受器、刚毛感受器、钟形感受器、栓锥感受器和板形感受器,其中毛形感受器最为丰富,约占总数的80％;雌、雄成虫触角上各种感受器类型及数量无明显差异.     

腰带长体茧蜂雌蜂触角的扫描电镜观察

采用扫描电镜技术对腰带长体茧蜂Microcentrus cingulum的触角感器进行了观察。结果表明,腰带长体茧蜂雌蜂触角上存在三种感器,分别为毛形感器、刚毛形感器、板形感器。对触角各种感器的形态和分布特点进行了描述,并就三类触角感器的功能进行了探讨。     

暗黑鳃金龟触角超微结构

利用扫描电镜对暗黑鳃金龟(Holotrichia parallela)雌、雄成虫的触角形态和感器进行了观察。结果表明:暗黑鳃金龟触角分为4部分,即柄节、梗节、鞭节棒状部和鳃状部,其中鞭节棒状部由5节组成,鳃状部由鞭节末端3节扩展构成。暗黑鳃金龟触角感器共7种,分别为板形感器、腔锥感器、腔形感器、刺形感器、毛形感器、锥形感器和Bhm氏鬃毛。雌、雄个体之间触角感器的类型、分布均没有明显差异。不同感器在触角各节上的数量与分布各不同。     

Variability of hard parts of opisthaptor of two species of Gyrodactylus nordmann, 1832 (Monogenoidea) from Phoxinus Phoxinus (L.).

The morphological and metrical variability of hard parts of opisthaptor was studied in the representatives of local populations of Gyrodactylus aphyae Malmberg, 1957 and G. macronychus Malmberg, 1957. The changes within the range of variability, which were observed during the year, correspond to regular and periodical changes in the environmental temperatures. The hard parts of opisthaptor were much smaller in specimens occurring during warm seasons than in specimens occurring during cold seasons. The temperature of about 8 degrees C forms a boundary between warm and cold seasons. The author assumes that similarly as G. aphyae and G. macronychus also other members of the genus Gyrodactylus living in climatic zones with regular change of seasons will react similarly on the annual variation in the environmental temperatures.     

柚木野螟幼虫头部形态及化学感受器扫描电镜观察

使用扫描电镜技术系统观察并描述了柚木野螟Eutectona machaeralis Walker幼虫触角及其口器上的化学感受器。观察结果如下:柚木野螟幼虫的头式为下口式,咀嚼式口器,头上有触角、单眼、感觉刚毛、上唇、下唇、上颚、下颚、下颚须、下唇须、吐丝器等。幼虫头部下方有1对触角,触角上有6种感受器,分别是毛形感器、短毛感器、锥形感器、刺形感器、栓锥感器和小锥形感器。口器附肢下颚须上有栓锥感器,下唇须上有刺形感器。在吐丝器前方有1对锥形感器。     

Neotropical Monogenoidea 37. Redescription of Gyrodactylus superbus (Szidat, 1973) comb. n. and description of two new species of Gyrodactylus (Gyrodactylidea: Gyrodactylidae) from Corydoras paleatus and C. ehrhardti (Teleostei: Siluriformes: Callichthyidae) of Southern Brazil

Two new species of Gyrodactylus (Gyrodactylidae) are described from Corydoras paleatus (Jenyns) and Corydoras ehrhardti Steindachner (Callichthyidae) of Rio Piraquara, Municipality of Piraquara, near Curitiba, Paraná, Brazil: Gyrodactylus anisopharynx sp. n. and Gyrodactylus samirae sp. n. These species are unique among the known Neotropical species of Gyrodactylus by the combination of several characters. Gyrodactylus anisopharynx is characterised by having hooks with point evenly curved, toe moderately pointed, round convex heel, straight sloping shelf, superficial bar with anterolateral projections and male copulatory organ armed with two rows of spinelets. Two variants of G. anisopharynx, of distinct pharynx size, are recognised: forma "large-pharynx" and forma "small-pharynx". Gyrodactylus samirae is characterised by having hook with straight shaft, short slightly recurved point, truncate toe, trapezoidal heel, shelf slightly concave, orthogonal to shaft; anchors with relatively short superficial root; superficial bar with extremities lightly expanded; and male copulatory organ armed with two rows of spinelets. Paragyrodactyloides superbus (Szidat, 1973) is redescribed and transferred to Gyrodactylus based on examination of type and new specimens. Features previously considered as diagnostic for the genus are misinterpretations or primitive characters for Gyrodactylus spp.