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1.
Predation on snails by three species of triclad and its bearing on the distribution of Planaria torva in Britain 总被引:3,自引:0,他引:3
Dugesia polychroa, D. lugubris and Planaria torva preyed upon snails of differing morphologies and while the Dugesia spp. fed approximately in proportion to snail abundance, PL torva was more selective on Potamopyrgus jenkinsi. The incidence of feeding on four snail taxa by the Dugesia spp. was significantly correlated and differed strikingly from that of PI. torva where feeding was related to its annual life cycle. Large peaks of feeding coincided in the Dugesia spp. for the four snail types; this was attributed to snail vulnerability being increased by environmental disturbance. Comparison of feeding by Dugesia spp. in the presence and absence of PI. torva indicated that severe competition was occurring for food with PI. torva having a food refuge in P. jenkinsi. The distribution of PI. torva in Britain is largely confined to productive habitats in the Glasgow-Edinburgh and East Anglia regions. It is concluded that historical rather than ecological events have played the major part in its distribution to date. The strong association of PL torva with port areas and the canal system suggests that it is a recent introduction via the timber trade with Fennoscania. 相似文献
2.
Ana Amorim Elsa Oliveira Manuel António E. Malaquias Alexandre Lobo-da-Cunha 《Zoomorphology》2013,132(2):145-155
In this study, semi-thin sections stained with histochemical techniques and transmission electron microscopy were used to obtain new data about the morphology and function of the male copulatory apparatus of the cephalaspidean gastropod Bulla striata. The apparatus comprises a vestibule, a penial papilla and a prostate consisting of a coiled unbranched tube ending in a blind caecum. The penial papilla and the coiled tubular prostate are enclosed by a muscular sheath, which is continuous with the muscular tissue of the vestibule. The epithelium lining the lumen of the vestibule is formed by ciliated and mucus-secreting cells. Two new types of subepithelial secretory cells were discovered in this region. The penial papilla is a muscular structure without secretory cells in the epithelium lining the narrow lumen. The tubule that constitutes the prostate possesses a muscular wall and can be divided in three distinct regions: a non-secretory duct connected to the penial papilla, a glandular region rich in large secretory cells and the terminal caecum containing just a few small secretory cells. In the terminal blind caecum, the muscular sheath is fused with the muscular wall of the tubular prostate. Large numbers of spermatozoa were found in the glandular region and in the terminal caecum of the prostate. A new functional mechanism is proposed to explain penial eversion during copulation. This differs from a previous hypothesis in two main aspects: (1) existence of a permanent penial papilla in mature animals acting as a functional penis and (2) functional role of vestibule during copulation, which everts and surrounds the penial papilla, while the latter protrudes outwards. 相似文献
3.
V L Bianki I M She?man E V Zubina 《Zhurnal vysshe? nervno? deiatelnosti imeni I P Pavlova》1990,40(1):102-107
Characteristics of spatial orientation in T-maze were studied in 1768 Planaria of following types: Dugesia tigrina (sexless and sexual race), Dugesia lugubris, Ijmia tenuis, Bdellacephala punctata. It was shown that from one third to one half of individuals were characterized by asymmetry of movement direction preference. The preference of right turning was typical for Dugesia tigrina; Dugesia lugubris, Ijmia tenuis, Bdellacephala punctata preferred left turning. The asymmetry described is considered as a primitive form of species functional asymmetry. 相似文献
4.
Feeding on gastropods by lake-dwelling Polycelis in the absence and presence of Dugesia polychroa (Turbellaria, Tricladida) 总被引:1,自引:0,他引:1
SUMMARY. Using a serological technique, the extent of feeding upon snails by Polycelis tenuis was compared in habitats lacking and containing Dugesia polychroa which is the major triclad predator of snails. It was found that P. tenuis ate significantly more snails when D. polychroa was absent. It was concluded that in the field interspecific competition for snails between these two triclad species was a more powerful process than any social feeding by P. tenuis on snails captured by D. polychroa .
Feeding on snails as a group by P. tenuis and P. nigra in the habitat where the two triclads co-existed was of a similar magnitude and this was also true of their feeding on the common snail species and genera. Approximately 10% of the triclads gave a positive reaction to snail antisera.
Feeding on snails by P. nigra in the three habitats lacking D. polychroa was similar in extent and did not differ from that of P. tenuis . It was concluded that P. nigra would be similarly affected by the presence and absence of D. polychroa as shown for P. tenuis .
No definitive seasonal pattern was detected in the incidence of feeding upon snails by either Polycelis species but this may have been obscured by seasonal changes in the detection period of snail antigens due to temperature effects. There was some evidence that such feeding increased during the period when small snails were present in the population. 相似文献
Feeding on snails as a group by P. tenuis and P. nigra in the habitat where the two triclads co-existed was of a similar magnitude and this was also true of their feeding on the common snail species and genera. Approximately 10% of the triclads gave a positive reaction to snail antisera.
Feeding on snails by P. nigra in the three habitats lacking D. polychroa was similar in extent and did not differ from that of P. tenuis . It was concluded that P. nigra would be similarly affected by the presence and absence of D. polychroa as shown for P. tenuis .
No definitive seasonal pattern was detected in the incidence of feeding upon snails by either Polycelis species but this may have been obscured by seasonal changes in the detection period of snail antigens due to temperature effects. There was some evidence that such feeding increased during the period when small snails were present in the population. 相似文献
5.
A new species of polyclad flatworm from Papua New Guinea is described. It is found symbiotic in the ophiuroid Ophiothrix purpurea von Martens, 1867 (Echinodermata: Ophiuroidea). Apparently it belongs to the taxon Discoplana Bock, 1913 and can be distinguished from the six previously described Discoplana species by its very short ejaculatory duct and a penial papilla covered with a penial sheath, but without any true sclerotised structures such as a stylet or spines. The cladistic analysis of the Discoplana/ Euplana species, based on morphological features and including two outgroups, reveals that all species of Discoplana, except D. pacificola, form a monophyletic taxon, that is not a synonym of Euplana Girard, 1893. Therefore the name Discoplana is conserved and the new species will be described as Discoplana malagasensis sp. nov. A key for the Discoplana/Euplana group is provided. In this key the biogeographical distribution and possible synonyms are given. 相似文献
6.
The enzyme 3',5'-nucleotide phosphodiesterase was localized in certain tissues of the planarian Dugesia lugubris (O. Schmidt) by means of ultracytochemical methods. This enzyme was found to be active in epithelium, muscles, nerve tissue and in rhabdite-forming cells. The active enzyme was present at the outer or inner side of the membrane, and even in the cytoplasm. Problems of the ultracytochemical localization of PDE are discussed. 相似文献
7.
Summary This paper compares aspects of the reproduction of a semelparous triclad, Dendrocoelum lacteum, with those of an iteroparous triclad, Dugesia polychroa. Cocoon output was less sensitive to ration and possibly temperature for the former as compared with the latter species. Cocoons of D. lacteum were on average bigger and contained more hatchlings than those of D. polychroa. The sizes of hatchlings did not differ between species, but for D. lacteum only, the hatchlings emerging from late cocoons were significantly larger, and less numerous, than those emerging from earlier cocoons. Possible reasons for these differences are considered. 相似文献
8.
Summary The functional morphology of the mammiliform penial glands ofLittorina saxatilis has been investigated with both light and electron microscopy. These penial glands line the ventral edge of the penis and orient with the female mantle during copulation. Secretions are released from the penial glands to this interface where they probably function in adhesion. The penial gland secretions comprise heterogeneous granules as well as apocrine and mucous secretions. The heterogeneous granules are produced in separate multicellular glands arranged in a series of lobes that lie outside a thick smooth muscle layer enclosing the lumen. Each glandular lobe is surrounded by a thin layer of smooth muscle. Secretions are transported in individual cellular processes that pass through the thick smooth muscle layer and empty into the lumen. Surrounding the lumen is an epithelium containing apocrine secretory cells as well as occasional goblet-type, mucous cells. The combined action of the muscles forces secretions out of the lumen through the penial papilla, onto the external surface of the mammiliform penial gland. Longitudinal muscles extend into the penial papilla enabling its protrusion or retraction. Retraction of the penial papilla following secretion release is thought to create negative pressure beneath the penial gland producing suction adhesion. The visco-elastic properties of the penial gland secretion are qualitatively different from foot mucus and may represent specialization to an adhesive function. 相似文献
9.
Nicole Gourbault 《Hydrobiologia》1981,84(1):45-52
Some species of Planarians, new to Spain, are recorded. Dugesia polychroa, D. sicula, D. iberica and D. gonocephala s. 1. have been investigated karyologically. The former possesses a diploid complement characteristic of the biotype A (2n = 8); the second is diploid with 2n = 18; diploidy and triploidy were found in sexual populations of D. iberica with n = 8. Triploidy occurred in all the asexual strains of the D. gonocephala group with a basic number of either 8 or 9. In this latter case B-chromosomes were occasionally found. 相似文献
10.
Humberto J. A. Moretto 《Hydrobiologia》1991,227(1):353-354
The taxonomic and distributional statuses of the freshwater planarians of South America are imperfectly understood, and a comprehensive review is sorely needed. The species known from the vicinity of Buenos Aires, Argentina, was first described by Böhmig (1902) under the name Planaria dubia Borelli, 1895. Subsequent authors (Kenk, 1930, 1974; Cazzaniga & Curino, 1987) have cast doubt on this assignation. Some have assigned it to Dugesia anceps Kenk; Hyman (1959) was inclined to regard the Buenos Aires planarian as a geographical variant of Dugesia sanchezi Hyman. A comparison of D. sanchezi from the mountainous region of central Chile with specimens from Buenos Aires confirms that the Argentinian material is a distinct species.The differences between the two species are subtle. The Argentinian specimens are distinctive in their possession of infranucleate epithelia of the atria, penis, and bursal canal, as well as in their penial structure. In both species, the epithelia of the atria and bursal canal are glandular. Those of D. sanchezi are nucleate and their secretions are cyanophilous. In the Argentinian specimens, these same epithelia are infranucleate; but while the secretion of the bursal canal is indeed cyanophilous, that of the atrium is erythrophilous. The presence, in these same specimens, of cyanophilous glands opening into the penial vesicles, and of erythrophilous glands whose secretions contribute to a viscous plug in the ejaculatory duct, suggests a difference in the physiology of copulation.It is apparent that the Argentinian specimens are distinct from D. sanchezi Hyman, and probably they represent a new species, one to be described in detail elsewhere. In any case, Hyman's (1959) suggestion that D. sanchezi occurs near Buenos Aires is mistaken; so also is Cazzaniga's & Curino's (1987) identification of specimens from Buenos Aires as D. anceps. 相似文献
11.
12.
The effects of natural methylmercury compounds on regeneration of photoreceptor organs were studied in three freshwater planarians: Polycelis tenuis, Dugesia lugubris, and D. tigrina. Accumulation of methyl mercury in the planarian body suppressed regeneration of P. tenuis with numerous photoreceptor organs to a greater extent than in two other planarians that have only two eyes. High methyl mercury concentrations inhibited the restoration of photoreceptor organs in asexual and sexual D. tigrina races. 相似文献
13.
Morpho-karyological Types of Dugesia (Turbellaria, Tricladida) in Israel and Their Distribution Patterns 总被引:2,自引:0,他引:2
Heather J. Bromley 《Zoologica scripta》1974,3(5-6):239-242
Populations of Dugesia in Israel have been classified on morphological and karyological criteria into 5 types. Two of these are morphologically similar to the Dugesia lugubris group (n = 4) but differ karyologically ( Types 1 and 2 : n=8), and three types are morphologically similar to the Dugesia gonocephala group ( n = 8) but two differ karyologically (Types 4 and 5: n = 9). The three ' gonocephala ' types are distributed in three distinct areas of Israel with little overlap, while the two ' lugubris ' types are found in springs of one of these areas, The Rift Valley, where special localised conditions prevail. Possible relationships between Types 3, 4 and 5 are discussed with particular reference to their karyotypes and the presence of supernumerary chromosomes in Type 5. 相似文献
14.
The effect of phorbol ester TPA (12-O-tetradecanoylphorbol-13-acetate) on head regeneration in decapitated planarians (Dugesia lugubris s.1.) has been studied. TPA-treatment soon after head amputation dramatically inhibited the regenerative process. Ultrastructural analysis revealed that the migration of fixed parenchymal cells (FPCs) to the wound area was strongly activated by TPA. FPCs interacted with various types of cells inducing lysis and phagocyting cell debris. The resulting fluid was removed through diaphanous protrusions appearing at the level of the wound zone. Moreover the close association of FPCs with neoblastlike cell clusters in the parenchyma indicated their possible role in the modulation of neoblast migration. 相似文献
15.
SAMUEL W. JAMES 《Zoologica scripta》1996,25(1):21-34
Nine species belonging to two distinct groups within the genus Dichogaster Beddard, 1888 are described from material collected on the volcanic section of the island of Guadeloupe. The species Dichogaster arborea, D. caesitifusca, D. callaina, D. girija and D. basseterrensis all inhabit the leaf tanks of bromeliads and share the following anatomical characteristics: spermathecal pores on the trailing edges of segments, spermathecal axis differentiated into ampulla, internally fluted central chamber and duct, penial setae long and slender, testes and funnels free, prostomium undivided or divided by two grooves, simple single typhlosole and a pair of dorsal caeca on the mid-intestine. Dichogaster athena also inhabits bromeliads, but lacks the above characteristics and male reproductive organs, and is more similar to the remaining species. The three remaining species, D. guadeloupensis, D. matoubensis and D. musciphila , with lateral typhlosoles, no intestinal caeca, simpler spermathecal structure, prostomiums divided by a single groove and short penial setae, all inhabit soils of montane forests. The division of Dichogaster based on muscularity of the proventriculus wall is shown to be unsupportable, since thickness of the wall is size-related. 相似文献
16.
The species Girardia biapertura Sluys, sp. nov. is described from the state of Rio Grande do Sul, Brazil. A unique derived character distinguishes this species from its congeners and all other planarians known to date, namely separate openings of the vasa deferentia at the tip of the penial papilla. Present knowledge on the distribution of Girardia species in Rio Grande do Sul is summarized. 相似文献
17.
Redescriptions of Phallodrilus parthenopaeus Pierantoni and P. obscurus Cook (Oligochaeta, Tubificidae) 总被引:1,自引:0,他引:1
CHRISTER ERSÉUS 《Zoologica scripta》1980,9(1-4):93-96
The type species of Phallodrilus Pierantoni, 1902, P. parthenopaeus Pierantoni, 1902; is redescribed on the basis of new material from W Scotland. The species is characterized by its specific spermathecal and penial setae, its very slender atria, and its long spermathecal ducts. Sexually fully mature specimens of P. obscurus Cook, 1969 are described for the first time, on the basis of material from New Jersey (E USA). The new material shows that this species possesses 5 to 9 penial setae in each ventral bundle of segment XI, and that its atria are coated with a relatively thick musculature. 相似文献
18.
Selected characters of the copulatory organs in the land planarian family Bipaliidae and their taxonomic significance (Tricladida: Terricola) 总被引:1,自引:1,他引:0
Preliminary analysis was made of 76 species in the monotypic family Bipaliidae, for which the copulatory apparatus has been
described. Four characters from the copulatory organs were selected: profile of the female organ (three character states),
approachment of the ovovitelline ducts to the female organ (two states), shape of the penial papilla (two states), and shape
of the male antrum wall (three states). Data were scored for five preliminary ingroup taxa, viz., the restricted genus Placocephalus,
and four other a priori defined subgroups within the family, viz., the genus Bipalium sensu stricto and three other informal
taxonomic groupings. An artificial outgroup taxon was constructed on the basis of character states generalized from the Geoplanidae
subfamilies Caenoplaninae, Pelmatoplaninae and Rhynchodemidae subfamily Microplaninae. Analysis of the data matrix resulted
in a single most parsimonious tree with the following topology: (outgroup (Placocephalus (Bipalium, group A (group B1, group
B2)))).
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
19.
20.
Rita Pascolini Simonetta Tei Daniela Vagnetti Carlo Bondi 《Cell and tissue research》1984,236(2):345-349
The epidermal cells that migrate over the surface during the wound closure stage of head regeneration in Dugesia lugubris s.l. were examined by scanning electron microscopy. The effect of cytochalasin B on epidermal cell migration was also examined. During the first few hours after decapitation epidermal cells at the edges of the wound showed significant changes of shape related to the process of migration that was accomplished approximately 10 h after wounding. Flattening of the marginal cells was associated with active epidermal spreading throughout the healing period. Suitable support for migrating cells appeared to be a rhabditic network attached to the wound tissue. Epidermal cell migration was inhibited by cytochalasin B. These results demonstrate that the basis for cell movement in planarians is similar to that of many other systems. 相似文献