Epiphallus anatomy in the Arion hortensis species aggregate (Mollusca, Pulmonata)

A SEM study of the structure associated with the outlet of the epiphallus in the atrium genitale of three arionid species ( Arion hortensis s.s., A. distinctus and A. owenii ) is presented. The structures are described and compared, and the specific differences are outlined. Preliminary notes on the same structure in A. intermedius , as well as on the spermatophores of A. hortensis s.s. and A. distinctus , are also provided. It is concluded that A. owenii stands somewhat apart in relation to the latter two species, since it may be more related to A. intermedius. Although it is generally accepted that the genus Arion is characterized by the absence of a penis, it is suggested here that the described structure at the outlet of the epiphallus is nothing but a remnant of an ancestral penis; anyhow, it is at least functionally allied to a penis.     

The effect of temperature on the activity of three species of Helicid snail (Mollusca: Gastropoda)

The activity of the land snails Cepaea nemoralis (L.), C. hortensis (Müll.) and Arianta arbustorum (L.) was measured over 24 hours at the constant temperatures of 0, 3, 8, 17, 22 and 26°C at 100% relative humidity and with 16 hours light and 8 hours dark. The activity of all three species varies significantly with temperature and light, and there are differences in the activities of the species at each temperature. A. arbustorum is relatively more active than Cepaea at low rather than high temperatures, as is C. hortensis with respect to C. nemoralis , though to a lesser extent. There is little diurnal rhythm in activity at 0°C, but all species become more nocturnal as temperature increases; C. nemoralis is most, and A. arbustorum least nocturnal. The results obtained assist in explaining the observed geographical and local distributions of the species concerned.     

Charge heterogeneity of rat pituitary prolactin in relation to the estrous cycle, gonadectomy, and estrogen treatment

Pituitary samples were obtained from female rats at various stages of the estrous cycle, and from intact male and gonadectomized rats with and without estradiol treatment. The pituitary extracts with 60% EtOH pH 9.5, were fractionated by preparative isoelectric focusing (IEF), and immunoreactive prolactin (IR-PRL) was measured by RIA. Three types of IR-PRL molecular species were found in these IEF profiles. The first type (species A) was consistently found in an area of pH 4.5-5.4, and consisted of two main subspecies with pls 5.0 (Al) and 5.25 (A2). Species A occupied most part of pituitary IR-PRL in males, gonadectomized animals, and in females in a basal state such as diestrus (D) II 17:00. Species A was also found exclusively in the serum at proestrus (PE) 19:00. The amounts of species A decreased notably when the secretion became active from PE 15:00 to 22:00, then increased at estrus (E) 6:00 and 10:00 when the second type (species B), which was found in the area of pH 5.4-6.8 only in trace amounts at basal states, increased markedly. Species B decreased again at E 17:00, while species A fully recovered. Species B also increased when PRL biosynthesis was stimulated by estradiol in intact male and gonadectomized rats. These findings indicate that species A must be the storage and secretory type of IR-PR, and that species B must be IR-PRL in the biosynthetic process which is to be finally converted into species A. A third type (species C) was found in a region of pH 3.5-4.5 in the IEF profiles of gonadectomized animals. This species is possibly IR-PRL molecules under degradation. When the pituitary was extracted serially with 0.25 M ammonium sulfate pH 5.5 (fraction AMS) first, then with 60% EtOH pH 9.5 (fraction ET), fraction AMS contained mostly species B and C, while fraction ET contained species A almost exclusively. The results obtained with this differential extraction roughly coincided with IEF data, though some disagreements were observed.     

山西维管植物新资料

报道了分布于中条山地区的山西省新记录维管植物14种,即鞘舌卷柏、华北薄鳞蕨、叉裂铁角蕨、秦岭耳蕨、榆钱菠菜、露蕊乌头、乌拉特绣线菊、小叶三点金草、奇异堇菜、纤弱黄芩、白透骨消、弯齿盾果草、野塘蒿、钻叶紫菀,隶属于12科14属。     

Populations of North American bean thrips, Caliothrips fasciatus (Pergande) (Thysanoptera: Thripidae: Panchaetothripinae) not detected in Australia

Abstract  Caliothrips fasciatus is native to the USA and western Mexico and overwintering adults are regular contaminants in the 'navel' of navel oranges exported from California, USA to Australia, New Zealand and elsewhere. Due to the long history of regular interceptions of C. fasciatus in Australia, a survey for this thrips was undertaken around airports, seaports, public recreational parks and major agricultural areas in the states of Queensland, New South Wales, Victoria, South Australia and Western Australia to determine whether C. fasciatus has successfully invaded Australia. Host plants that are known to support populations of C. fasciatus , such as various annual and perennial agricultural crops, urban ornamentals and weeds along with native Australian flora, were sampled for this thrips. A total of 4675 thrips specimens encompassing at least 76 species from a minimum of 47 genera, and three families were collected from at least 159 plant species in 67 families. Caliothrips striatopterus was collected in Queensland, but the target species, C. fasciatus , was not found anywhere. An undescribed genus of Thripidae, Panchaetothripinae, was collected from ornamental Grevillea (var. Robyn Gordon) at Perth (Western Australia) Domestic Airport, and is considered to be a native Australian species. This survey has provided valuable information on the background diversity of thrips species associated with various native and exotic plant species around major ports of entry and exit for four of five states in Australia. We suggest that the major reason C. fasciatus has not established in Australia is due to high adult mortality in navels that are kept at low storage temperatures (2.78°C) during an 18- to 24-day transit period from California to Australia.     

The effects of density and interspecific interaction on mortality in experimental populations of adult Cepaea (Held.)

Field population cages were used to investigate the effects of density and interspecific interactions on adult mortality in two closely related species of landsnail, C. nemoralis (L.) and C. hortensis (Mull). High densities were associated with increased mortality in both species. Increased mortalities were also observed in populations in which the two species were placed together, compared to those in which each was kept separate. However, this trend was not consistent for populations which contrasted in density levels. The effect of C. hortensis on C. nemoralis was greater at low densities than at high densities. The results suggest that coexistence in nature may be unstable and could result in spatial displacement.     

The survival, weight-loss and behaviour of three species of land snail in conditions of low humidity

Cepaea nemoralis L., C. hortensis Mull, and Arianta arbustorum L. show differences in survival, rate of water-loss and behaviour under conditions of low humidity in laboratory studies. C. nemoralis survives better, ceases activity more rapidly, and loses proportionally less weight in low humidity than C. hortensis , which in turn shows the same properties with respect to A. arbustorum . The differences between these three species are reflected in differences in distribution in parts of Britain.     

The distribution and variation of three species of land snail near Rickmansworth, Hertfordshire

The distribution of Arianta arbustorum, Cepaea nemoralis and C. hortensis , and the variations in the shell polymorphism of the Cepaea species have been studied in an area of low chalk downland and alluvial river valleys near Rickmansworth, Hertfordshire. The distribution of A. arbustorum is restricted, the species being largely confined to the bottoms of river valleys, especially in hedgerows. Variations in dampness seem the most likely limiting factor. C. hortensis is widespread and found in many habitats, but C. nemoralis is largely confined to woods, and is especially common in beechwoods. The morph-frequencies of C. nemoralis and C. hortensis vary in such a way as to suggest the operation of climatic and visual selection. In C. hortensis there are area effects for the presence or absence of pink five-banded shells, and there is an overall linkage disequilibrium resulting in an excess of unbandeds in non-yellow shells. Reasonable evidence for the operation of random factors in determining the morph-frequencies of populations of Cepaea in the area has been found only for three very disturbed populations. It is suggested that the large number of selective forces known to act on Cepaea populations in this area will account for the variation in morph-frequencies in populations from the same area or habitat.     

First report of Siphonaptera infesting Microtus (Microtus) cabrerae (Rodentia-Muridae-Arvicolinae) in Cuenca,Spain and notes about the morphologic variability of Ctenophthalmus (Ctenophthalmus) apertus personatus (Insecta-Siphonaptera-Ctenophthalmidae)

The fleas infesting Microtus (Microtus) cabrerae from three different areas of Cuenca province (Spain) have been studied. It is the first time that on ectoparasitological study of this badly known rodent has been done. Four Siphonaptera species have been detected: Rhadinopsylla (Actenophthalmus) pentacantha, Peromyscopsylla spectabilis spectabilis, Nosopsyllus fasciatus and Ctenophthalmus (Ctenophthalmus) apertus personatus, which was the most abundant species (26 males and 31 females of a total of 28 males and 35 females). Considering the great morphologic variability within the male processus basimerus ventralis (p.b.v.) of segment IX of C. personatus subspecies, three morphotypes have been recognised. The male polymorphism detected, would be the result of both host confinement and genetic selection acting on the parasite. It should be pointed out that C. (C.) apertus personatus is not narrowly host-specific, therefore further studies are required to clarify this taxonomic situation.     

The genus Koenigia L. emend. Hedberg (Polygonaceae)

Pollen morphological studies revealed the occurrence of the characteristic spinulose pollen type of Koenigia not only in the three species earlier recognized in the genus (A" islandka, K. nepalensis and K. pilosd) but also in three additional species earlier treated under Polygonum , viz. K delicatula (Meisn.) Hara, K. forrestii (Diels) Mesicek & Soják, and A" nummularifolia (Meisn.) Mesicek & Soják. Further studies of flower morphology, fruit and petiole anatomy, basic chromosome number, etc., revealed additional similarities between those species, which led to a taxonomic revision of the genus Koenigia. This genus seems to be most closely related to Persicaria Mill, sections Cephalophilon (Meisn.) Gross and Echinocaulon (Meisn.) Gross, with Koenigia delicatula as a connecting link. There arc also interesting similarities with the genus Aconogonon (Meisn.) Rchb. Koenigia exemplifies the derivation from montane ancestors of a high mountain-dwelling genus displaying adaptive radiation to fit diverse alpine niches. Five species out of six are confined to high mountain areas in southeastern Asia, primarily in the Himalayas, whereas the sixth has spread to Arctic and alpine areas in the northern hemisphere and even penetrated to southern South America. The latter species shows progressive reduction in size in combination with adaptation to a very short summer under severe climatic conditions.     

The effect of interspecific interaction on spatial distribution patterns in experimental populations of Cepaea nemoralis (L.) and C. hortensis (Müll.)

'Choice-chamber' population cages were used to investigate distribution patterns in mixed and unmixed populations of closely related species of landsnails, C. nemoralis (L.) and C. hortensis (Müll.). Numbers of snails migrating into cut-grass cages were affected by mixing the two species. The direction of response was not the same for both siblings. The results indicate that interspecific interaction could affect species' distribution patterns in free-living populations.     

Two new species of Cichlidogyrus Paperna, 1960 (Monogenea, ancyrocephalidae) gill parasites on Hemichromis fasciatus (Pisces, Cichlidae) in Africa, with remarks on parasite geographical distribution

The examination of gill parasites from Hemichromis fasciatus Peters, 1858 (Pisces, Cichlidae) in Africa revealed the presence of nine species of Monogenea, three belong to Onchobdella Paperna, 1968 and the others to Cichlidogyrus Paperna, 1960. Seven have been previously described (O. aframae Paperna, 1968; O. bopeleti Bilong Bilong & Euzet, 1995; O. voltensis Paperna, 1968; C. dageti Dossou & Birgi, 1984; C. euzeti Dossou & Birgi, 1984; C. falcifer Dossou & Birgi, 1984 and C. longicirrus Paperna, 1965); two, belonging to the latter genus, are considered as new species: C. sanseoi n. sp. and C. teugelsi n. sp. As parasitic species are not present in all the host distribution area, we think that H. fasciatus is made up of two distinct populations (or even sister species).     

Toxicity of several pesticides used in Tunisia, for Aphanius fasciatus Nardo, 1827 (Pisces, Cyprinodontidae.)

The acute toxicity of some pesticides used in Tunisia is determined for the species Aphanius fasciatus (Pisces - Cyprinodontidae). Bioassays conducted at temperature (19-20 degrees C) and salinity (37-38%) have allowed to calculate the CL50 48 h and 96 h. The classification of these pesticides, based on the CL50 96 h, and according to their toxicity for the test species, shows that the organic phosphorus (Murphotox, Bazudin, Dursban, Zithiol, Lebaycid, Imidan, Oleoparathion, Folimat; Nuvan, Actellic, Carbicron, Nexion, Dimecron, Roxion) have all the degrees of toxicity, but the majority are among the most toxic; the carbamates (Betanal, Dimetilan, Baygon), are generally less toxic than the organic phosphorus tested, except Nexion which is less toxic than the Betanal and Roxion less toxic than the three carbamates tested; the herbicides (2,4-D, Basagran, Printan) have a very low toxicity, and are less toxic than the insecticides tested, except Betanal and Suffix of which the toxicity is higher than some insecticides (Nexion, Dimecron, Baygon, Dimetilan, Roxion); Calixin (Fongicide) is more toxic than the herbicides tested but it is generally less toxic than the insecticides used. At higher temperature (28-29 degrees C) A. fasciatus is more sensible to organic phosphorus (Dursban, Folimat) than to carbamate (Betanal). The variation change of salinity (from 37 to 6.5 %) don't modify the sensibility of the test species face to face of three pesticides: Dursban, Folimat (organic phosphorus insecticide) and Betanal (carbamate herbicide). A. fasciatus is suitable for acute and chronic bioassays.     

辽宁省丹东地区吸血蠓类(双翅目:蠓科)生态调查

吸血蠓类对人畜危害较大,不仅是多种疾病的传播媒介,而且刺叮吸血骚扰性很大。1988年我们在辽宁省丹东地区东沟和风城二县郊区进行了采集和生态习性的调查,现将结果报道如下。材料和方法器材由军事医学科学院微生物流行病研究所提供的诱蠓帐、捕虫网和吸虫器。调查方法     

The chromosomes of Cepaea vindobonensis (Pulmonata: Helicidae) and the relationship between this species and the rest of the genus

The karyotype of Cepaea vindobonensis (Pfeiffer) (2 n = 50) is defined and compared with those of C. sylvatica (Draparnaud), C. nemoralis (L.) and C. hortensis (Müller). Cepaea vindobonesis shares its chromosome number with C. sylvatica. The genus Cepaea thus consists of two pairs of species, one with 2 n = 50 the other with 2 n = 44. The karyotype of C. vindobonensis is distinct from that of C. sylvatica as it lacks any discontinuity in its range of chromosome length and has all three of its longest chromosome pairs nearly identical. The two 2 n = 50 species both have an unusual meiotic bivalent showing a 'satellite-type' structure. It is apparent that the 2 n = 50 species are more closely related to each other than to the 2 n = 44 species. No precise definition of the evolutionary history can be given but a working hypothesis is suggested.     

The karyotype of Cepaea sylvatica (Pulmonata: Helicidae) and its relationship to those of C. hortensis and C. nemoralis

The karyotypes of Cepaea nemoralis (L.) and C. hortensis (Müller), with 2n=44 and a conspicuously large pair of chromosomes, are described and compared with that of C. sylvatica (Draparnaud) which has 2n=50. The karyotype of C. sylvatica also has a conspicuously large pair of chromosomes but the comparison suggests that these have an independent origin from those in the 2n = 44 species. There is no evidence that the large chromosomes in C. nemoralis and C. hortensis have originated from simple fusion of chromosomes from a 2n=50 karyotype with chromosomes all sub-equal such as is reported for C. vindobonensis. It may be that such a karyotype with little size differentiation amongst the chromosomes is not a primitive feature in the Helicinae. The relationship of shell colour and banding polymorphism to the chromosome architecture is discussed.     

The rhabditid nematode Phasmarhabditis hermaphrodita as a potential biological control agent for slugs

A nematode, Phasmarhabditis hermaphrodita, known to be associated with slugs but not previously thought to be parasitic, was shown to be a parasite capable of killing the pest slug Deroceras reticulatum. The parasite infects slugs in the area beneath the mantle surrounding the shell, causing a disease with characteristic symptoms, particularly swelling of the mantle. Infection leads to death of the slug, usually between seven and 21 days afterwards. The nematode then spreads and multiplies in the cadaver. In an experiment where individual D. reticulatum were exposed to different numbers of P. hermaphrodita, a significant positive relationship was found between nematode dose and slug mortality. In two experiments on host range, the nematode was found to infect and kill all pest slug species tested: Deroceras caruanae, Arion distinctus, Arion silvaticus, Arion intermedius, Arion ater, Tandonia sowerbyi and T. budapestensis, in addition to D. reticulatum.