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1.
The deer ked, Lipoptena cervi L. (Diptera: Hippoboscidae), is an ectoparasitic fly that spread to Finland in the early 1960s from the southeast across the Soviet border. It is currently a common parasite of the moose, Alces alces (Artiodactyla: Cervidae), in the southern part of the country and its area of distribution is gradually spreading to Finnish Lapland, where it will come into contact with another potential cervid host, the semi‐domesticated reindeer, Rangifer tarandus tarandus. The aim of this study was to determine the intensity of deer ked parasitism on the moose in eastern Finland. Whole skins of 23 moose were examined for the presence of deer keds, which were extracted and their total numbers estimated. The intensity of deer ked parasitism was correlated to the age, sex, skin area and anatomical region of the host. Bulls had the highest total number of keds (10616 ± 1375) and the highest deer ked density (35.7 ± 4.4 keds/dm2 of skin). Cows had a higher total number of keds than calves (3549 ± 587 vs. 1730 ± 191), but ked densities on cows and calves were roughly equal (11.8 ± 1.7 vs. 9.4 ± 1.1 keds/dm2 of skin). The density of keds was highest on the anterior back, followed by the posterior back, front limbs, abdomen, head and hind limbs. The sex ratio of deer keds was close to equal (male : female, 1.0 : 1.1). After they had consumed blood, male keds were heavier than females. As the total numbers and densities of deer keds were higher than reported previously on moose or for any other louse fly species, the effects of parasitism on the health of the host species should be determined.  相似文献   

2.
The pituitary vascular system of Anolis carolinensis is similar to that of other lizards. Distinct portal vessels connect the primary plexus of the median eminence with the secondary plexus of the pars distalis. The primary plexus has some connections with the neural lobe. The neural lobe plexus is fed by separate arteries, and drains into the pars intermedia. The latter lobe receives its blood supply by this route. The pituitary is drained into the vena retrohypophysea. The findings are discussed in relation to existing theories regarding the neurovascular control of the pars intermedia.  相似文献   

3.
It is recognized by the FAO that management of fish resources in the western Indian Ocean is complicated by the lack of data on the basic biology and landing statistics for exploited fish species. In this paper data are presented on the population biology of kingsoldier bream, Argyrops spinifer (Forsskål 1775), in the Arabian Sea with a view to contributing towards the development of management plans for its sustainable exploitation. Samples were obtained from the Omani artisanal hand‐line fishery catch, January 2001–December 2002. Total length (LT) of fish sampled ranged from 20 to 68 cm (males) and 25 to 70 cm (females). The male : female ratio was similar up to 55 cm LT but the larger size‐classes were composed predominately of male fish. LT/carcass weight (WC) relations for male and female fish were similar and the combined data produced an equation WC = 0.00005 × LT2.67. Marginal increment analysis indicated an annual cycle of opaque and translucent ring formation in otoliths that was related to the change in surface water temperature during the annual monsoon period. The opaque zone was completed in May and the translucent zone began to form in June. Female and male fish age ranged between 2 and 25 years. Both males and females exhibited similar asymptotic growth patterns; the combined von Bertalanffy growth function was Lt = 64.6(1 ? e[?0.142(t + 0.489)]). Gonadosomatic indices and gonad condition of male and female fish indicated that the spawning season occurred between September and January. Size (L50) and age at first maturity (A50) were estimated to be 36.5 cm LT and 5.0 years for males and 37.2 cm LT and 5.6 years females, respectively. The results of this study provide fundamental information on the biology and population dynamics of A. spinifer in the Arabian Sea that can be used in management models for the continued sustainable exploitation of this species in the Omani demersal coastal fisheries.  相似文献   

4.
Summary In order to understand the blood flow patterns and their regulation in the gills and pulmonary artery ofAmbystoma tigrinum, the vascular resistance and vasoactivity of the two major branchial perfusion pathways and a vascular plexus in the pulmonary artery were investigated using an isolated-tissue perfusion method. Acetylcholine and epinephrine were both pressor agents in all three vascular segments. Angiotensin II also constricted the branchial respiratory vasculature. Norephinephrine was primarily a vasodilator in the branchial respiratory vasculature, however, it had no effect on the shunt vessels of the gill or the pulmonary arterial plexus. Both gill circulations were insensitive to alterations in CO2 and pH. Anoxia produced a slight vasodilation of the branchial respiratory vessels but had no effect on the shunt vasculature. Mild hypoxia had no effect on either branchial circulations. The results suggest that: (1) blood flow through the respiratory section of the gill may vary between 8 and 47% of total gill flow, (2) the major perfusion pathway to the lung is probably from the efferent artery of the third gill through the ductus arteriosus and then into the pulmonary artery, (3) O2, CO2 and pH exert no local control of branchial perfusion, (4) both cholinergic and adrenergic regulation of branchial and proximal pulmonary arterial vascular resistance is possible, (5) a rise in circulating norepinephrine should increase blood flow to the respiratory section of the gill.Abbreviations AII angiotensin II - ACh acetylcholine - EPi epinephrine - NE norepinephrine  相似文献   

5.
Behavior of the eyespots during the fertilization of Ulva arasakii Chihara was studied using field emission scanning electron microscopy (FE‐SEM). FE‐SEM enabled the visualization of the eyespot of biflagellate male and female gametes. The smaller male gamete has one protruded smaller (1.3 ± 0.15 μm× 1.0 ± 0.29 μm) eyespot and the larger female gamete has a larger (1.6 ± 0.2 μm× 1.1 ± 0.13 μm) one on a posterior position of the cell. The cell membrane over the eyespot region is relatively smooth compared to other parts of the cell body and exhibits hexagonal arranged lipid globules. Because the size of the cell and the morphology of the eyespot are different between male and female gametes, we could follow the fate of the eyespots during the fertilization. The initial cytoplasmic contact and fusion of the gametes takes place at their anterior end, slightly posterior to the flagellar base. The morphology of the fusing gametes followed two clearly distinguishable patterns. About half the gamete pairs lie side‐by‐side with their longitudinal axes nearly parallel, while the rest are oriented anti‐parallel to each other. In all cases, the larger female gamete fused along the same side as the eyespot, while the smaller male gamete fused along the side away from its eyespot. As fusion proceeds, the gamete pair is transformed into the quadriflagellate planozygote, in which the eyespots are positioned side‐by‐side on the region of cell fusion. These observations indicated that the opposite positioning of the eyespot relative to the cell fusion site in male and female gametes is important for the proper arrangement of the eyespots in the planozygote. The significance of this feature in advanced green algae is briefly discussed.  相似文献   

6.
Strongyloides spearei n. sp. is described from the small intestine of the common wombatVombatus ursinus from Healesville, Victoria. The new species is distinguished from all known congeners by: the triangular shape of the stoma and the length of the parasitic female; the blunt spicules in the free-living male; and the presence of eggs in the faeces of the host.S. spearei andS. thylacis Mackerras, 1959 form a separate group withinStrongyloides based on both species infecting marsupials, having directly recurrent ovaries in the parasitic female and having blunt spicules in the free-living male. The histological localisation ofS. spearei is predominantly within the crypts of the small intestine.  相似文献   

7.
8.
Argyrops spinifer and Rhabdosargus haffara are two sympatric seabream species making important contributions to fisheries landings in the western Arabian/Persian Gulf. We identified the strengths and weaknesses in the long-term sustainability of A. spinifer and R. haffara stocks by integrating multiple sources of data, including fisheries catch and effort statistics, life history traits, scientific trawl surveys and historical length frequency distribution. Four strengths were identified in A. spinifer: wide distribution of juveniles, positive association to the network of de facto fishing exclusion areas created by hundreds of oil-gas facilities, early maturation and the existence of large and old individuals. A. spinifer suffers from two potential weaknesses: slow growth rate and higher exploitation pressure on the small-sized individuals. R. haffara, on the other hand, has a strength of having a short life span and a fast growth rate, characteristics that make it robust to unfavourable conditions. R. haffara suffers from two weaknesses: the lack of association to the oil and gas facilities, and the preference for nearshore shallow waters with stronger negative anthropogenic impacts. Identified strengths and weaknesses of these two sparids provided a preliminary assessment about their long-term sustainability, as well as a roadmap about how to develop different management strategies to meet specific objectives.  相似文献   

9.
Albrecht, U., Lametschwandtner, A., Adam, H. 1979. The vascularization of the anuran brain. Diencephalon and choroid plexus. A scanning electron microscopical study of vascular corrosion casts. (Department of Zoology, University of Saulzburg, Austria.) — Acta zool. (Stockh.) 61(4): 203–220. The vascularization of the diencephalon (with choroid plexus of the third ventricle, epithalamus and pineal region, thalamus and hypothalamus) of the toad, Bufo bufo (L.) has been studied by means of scanning electron microscopy of vascular corrosion casts. To localize angioarchitectonic patterns of distinct diencephalic regions the authors refer to critical point dried specimens and to histological sections. In the choroid plexus a supply via one choroid artery, which arises from the posterior telencephalic artery, was found. Its strict dichotomous branching is pointed out. In generally a similar vascular pattern like that in the choroid plexus of the fourth ventricle has to be reported. Furthermore the epithalamic region with the epiphysial area was under investigation. No special angioarchitecture of the epiphysis was found. There are also no prominent vascular connections with thalamic or hypothalamic regions. The thalamic region is supplied by branches of the posterior telencephalic artery as well as by branches of the preoptic artery. Epithalamic and thalamic regions are drained via the posterior diencephalic vein. Special attention was also paid to the preoptic, the chiasmatic and the retrochiasmatic area. No special vascular connections, however, were found.  相似文献   

10.
Male-killing is 1 of 4 known strategies that inherited parasitic endosymbionts have evolved to manipulate their host's reproduction. In early male-killing, infected male offspring are killed early in embryogenesis. Within the Insecta, male-killing bacteria have been found in a wide range of hosts. The Coccinellidae families of beetles, better known as ladybirds, are particularly prone to male-killer invasion. In samples of the coccinellid, Coc- cinula crotchi, from Japan, a new male-killing bacterium was revealed by phenotypic assay. Molecular genetic analysis revealed the identity to be a tetracycline-sensitive Flavobac- terium that causes female-biased offspring sex ratio. Furthermore, that Flavobacterium strain was found to be closely related to the Flavobacterium causing male-killing in the congeneric Japanese coccinellid, Coccinula sinensis, which was collected from the same region. However, we found slightly different Flavobacterium strains infecting C. sinen- sis from regions with different environmental conditions. This may be an indication of horizontal transmission of male-killing Flavobacterium between these 2 ladybird spices. Finally, environmental conditions may affect the spread of male-killing bacteria among their hosts.  相似文献   

11.
Akira Chiba  & Masahiko Nakamura 《Ibis》2002,144(2):E96-E104
This paper describes the histological features of the prominent cloacal protuberance (CP) of sexually mature females of the polygynandrous Alpine Accentor Prunella collaris . In the copulation period, the CP of the prelaying mature female developed remarkably and the lips of the vent turned brilliant scarlet. Macroscopic and microscopic examination of the cloacal region from females of different ovarian maturity showed that the formation of the CP was mainly due to the hypertrophy of the cloacal musculature, i.e. the sphincter cloacae muscle and levator cloacae muscle, and to the development of the associated connective tissue in the sexually mature female. The scarlet coloration of the cloacal lips was ascribed exclusively to the development of the dermal vascular plexus accompanied by hyperaemia, as characterized by the dilated blood vessels filled with blood. There was no evidence that skin pigmentation was involved in the scarlet coloration of the cloacal lips. We speculate that the morphological changes in the cloacal lips of the female Alpine Accentor are mediated hormonally by the brain–pituitary–gonadal axis.  相似文献   

12.
Synopsis Adult Melanostigma atlanticum were observed living 15 to 32 cm deep within sediment box cores from 350 m depth in the Laurentian Trough of the Maritime Estuary of the St. Lawrence. The fish were found in fluid pockets or burrows of brown-coloured (oxygenated) silty clay within the anoxic zone of the sediment. In August 1983, four individuals (3 male and 1 female) were recovered from pockets located 15 and 32 cm below the sediment surface. All specimens were greater than 100 mm in length, had empty stomachs, and the female carried no eggs. In July 1985, 6 individuals (1 male and 5 females) were found in a head to tail arrangement within a single burrow at 18–20 cm depth. Three of the females carried eggs, while two appeared to have already released their eggs. A cluster of about 50 large eggs, some of which appeared to have been fertilized, was also found in the burrow. Most of the stomachs were empty, but one contained two copepods, another a proceroid cestode, and others contained between 4–22 parasitic hemiurid trematodes. These observations indicate that burrowing into bottom sediments is important in the reproductive behaviour of M. atlanticum.  相似文献   

13.
Mauricio M. Rocha 《ZooKeys》2013,(340):107-117
The imago and soldier castes of the Neotropical Termitinae species Genuotermes spinifer Emerson are redescribed. The gut anatomy of the worker is described in detail for the first time, and morphological variations in the soldier are noted and illustrated. The known geographical distribution of Genuotermes spinifer is greatly expanded.  相似文献   

14.
Sternostoma tracheacolum was found to be ovoviviparous, laying eggs in the lung of the host. Larvae hatch shortly after oviposition and moult without feeding. Following a blood meal female protonymphs move to the posterior airsacs while male protonymphs tend to stay within the lung to complete development. Gravid females tend to occupy the airsacs, the syrinx and trachea of the host while adult non-gravid, non-gorged females are more commonly found in the upper respiratory system, particularly the buccal and nasal cavities. In vitro rearing experiments and other observations indicate that the life cycle (from egg to adult) is completed in less than 6 days. Transmission is accomplished by the adult non-gravid, non-gorged female and this stage is often encountered on the head plumage, bill and nares of infected birds. Observations on the behaviour and survival of the transmissible indicate a potential for direct transmission between hosts in close proximity and indirect transmission via water, perches or other surfaces. Adult male mites tend to be common in small infrapopulations but uncommon and often absent in large infrapopulations, supporting an argument for parthenogenesis and an arrhenotokous system of sex determination.  相似文献   

15.
Arenicola marina gills are hollow, branched, body outgrowths with a central coelomic cavity and afferent and efferent vessels. The gill surface area per unit body weight is about 4 cm2/g wet weight. The blood vascular system anatomy differs from the tip to the base of the gill. In the distal branches of the gill the superficial afferent and efferent vessels are joined by connecting vessels. All vessels arise as spacings between the basal laminae of the thin epidermis and of the coelomic myoepithelium. The contractile part of this epithelium mainly borders the afferent and efferent vessels, whereas pedicel-like cytoplasmic processes extend from the cell bodies and mainly line the connecting vessels. In the proximal branches of the gill the afferent and efferent vessels located in the coelomic cavity are surrounded by the coelomic myoepithelium, and a peripheral blood plexus is present below the epidermis. The gill epidermis is everywhere thin and does not exhibit the characters of a transporting epithelium. The gill coelomic myoepithelium has several functions: (i) periodic contractions of the gill, propelling blood and coelomic fluid toward the central vascular and coelomic compartments; (ii) blood ultrafilration toward the coelomic cavity; (iii) probably transport, suggested by the specialized structures of the lateral membranes of the cells.  相似文献   

16.
ABSTRACT Carotenoid‐based coloration of skin and plumage has been found to be correlated with individual quality in many species of birds during the breeding season. However, less is known about the possible role of these signals during the nonbreeding season, particularly among nonpasserines that defend winter territories. American Kestrels (Falco sparverius) are sexually dimorphic raptors that defend winter territories and possess carotenoid‐based morphological features known to be correlated with individual quality. Much is known about winter territory use and habitat segregation by male and female kestrels, but possible relationships among morphological features, individual quality, and habitat quality have not been examined. Our objective was to examine possible relationships between morphology, territory quality, and skin color of American Kestrels. Male kestrels had brighter skin than females, and the skin color of male kestrels was positively correlated with size (wing chord and tail length) and territorial quality (hunting territories with less canopy and more grass cover). No such relationships were found for female kestrels. Skin color appears to be an honest indicator of quality for male American Kestrels and may serve both intersexual (territory acquisition) and intersexual (mate choice) functions during the breeding and nonbreeding seasons.  相似文献   

17.
A survey of species of the prunoid genera, Maddenia and Pygeum, and of the genus Osmaronia has been made. The ovules of all are pendent, campylotropous, and epitropic. In the prunoids, the ovular supply is intimately connected with a central vascular plexus in the base of the carpel; that plexus is absent from Osmaronia. The prunoid carpels are marked by an extensive degree of fusion among the ovular and wing bundles, by fusion of the sutural margins, by fusion of the 2 integuments of the ovule to a single massive one, and by the presence of 3 or 5 well-developed bundles in the base. The carpel of Osmaronia also has a strongly fused bipartite ovular supply, separate bundles of which, however, become very much attenuated before reaching the funiculus; it has independent ovular and wing bundles, completely separate carpellary margins, 2 clearly separate integuments in the ovule, and 6 distinctive bundles in the carpel base. At the funiculus, the wing bundle of Osmaronia is connected with the adjoining weak ovular bundle by a well-developed vascular branch. Various particularities in the morphology of Osmaronia lend support to its segregation into a unique tribe, the Osmaronieae of Rydberg.  相似文献   

18.
The term spinal accessory nerve plexus may be defined as the spinal accessory nerve with all its intra- and extracranial connections to other nerves, principally cranial, cervical, and sympathetic. The term is not new. This review examines its applied anatomy in head and neck cancer and atherosclerosis. Over the centuries, general studies of neural and vascular anatomy and embryology formed a basis for the understanding upon which the plexus is described. During the past century, its anatomy and blood supply have come to be better understood. The importance of almost all of the plexus to head, neck, and upper extremity motor and sensory functions has come to be realized. Because of this understanding, surgical neck dissection has become progressively more conservative. This historical progression is traced. Even the most recent anatomic studies of the spinal accessory nerve plexus reveal configurations, new to many of us. They were probably known to classical anatomists, and not recorded in readily available literature, or not recorded at all. Human and comparative anatomic studies indicate that the composition of this plexus and its blood supply vary widely, even though within the same species their overall function is very nearly the same. Loss of any of these structures, then, may have very different consequences in different individuals. As a corollary to this statement, data are presented that the spinal accessory nerve itself need not be cut during surgical neck dissections for severe impairment to occur. In addition, data are presented supporting the theory that atherosclerosis by obstructing vessels to this plexus and its closely connected brachial plexus will very likely result in their ischemic dysfunction, often painful. Finally evidence, as well as theory, is stated concerning anatomic issues, methodology, outcome, and possible improvements in surgical procedures emphasizing conservatism.  相似文献   

19.
Prox1, master regulator of the lymphatic vasculature phenotype   总被引:12,自引:0,他引:12  
In contrast to the extensive molecular and functional characterization of blood vascular endothelium, little is known about the mechanisms that control the formation and lineage-specific differentiation and function of lymphatic vessels. The homeobox gene Prox1, the vertebrate homologue of the Drosophila prospero gene, has been recently identified to be required for the induction of lymphatic vascular development from preexisting embryonic veins, and studies in Prox1-deficient mice have confirmed Florence Sabin's original hypothesis about the origin of the lymphatic vascular system from embryonic veins. The recent establishment of cell culture models for the selective propagation of blood vascular and lymphatic endothelial cells, together with the findings that these cells maintain their lineage-specific differentiation in vitro, has led to the discovery that Prox1 expression is sufficient to induce a lymphatic phenotype in blood vascular endothelium. Ectopic expression of Prox1 downregulated blood vascular-associated genes and also upregulated some of the known lymphatic endothelial cell markers. Together, these studies suggest that the blood vascular phenotype represents the default endothelial differentiation and they identify an essential role of Prox1 in the program specifying lymphatic endothelial cell fate.  相似文献   

20.
A new Conchostracan species, Eocyzicus spinifer from Iraq is described. A table is given to distinguish the known species of the genus Eocyzicus.  相似文献   

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