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Habitat fragmentation is a major cause for species loss, but its effect on invertebrates with low active dispersal power, like terrestrial gastropods, has rarely been studied. Such species can not cross a hostile habitat matrix, for which the predictions of island theory, such as positive relations between species richness and patch size, should apply. In order to test this prediction, we studied gastropod species diversity by assessing gastropod assemblage characteristics from 35 sites in 19 fragments of deciduous old-growth forests in the Lower Rhine Embayment, Germany. Assemblages differed between larger (⩾700 ha) and smaller forests (\400 ha), those of large forests held a higher percentage of forest species. Although α-diversity was similar between the two forest size classes, small forests often comprised matrix species, resulting in a higher β-diversity. Edge effects on the species richness of matrix species were noticeable up to 250 m into the forest. Hierarchical partitioning revealed that distance to disturbances (external edge, internal edges like roads) explained most assemblage variables, whereas forest size and woodland cover within a 1 km radius from the sites explained only a few assemblage variables. Densities of two forest-associated species, Discus rotundatus and Arion fuscus, decreased with forest size. Yet, forest size was positively correlated with richness of typical forest species and densities of Limax cinereoniger. The latter species seems to need forests of [1,000 ha, i.e., well above the size of most fragments. In conclusion, the prediction is valid only for forest species. The response to fragmentation is species specific and seems to depend on habitat specialization and macroclimatic conditions. [ABSTRACT FROM AUTHOR]

This paper deals with the orientational behaviour in the two terrestrial slugs Arion rufus and Deroceras agreste. It presents anatomical details of their eyes and provides an appraisal of the eyes’ optical system. In both species the retinae contain two principal types of cell: photoreceptive and pigmented supportive cells. While only the eye of A. rufus apparently contains neurosecretory neurones, that of D. agreste is the only one equipped with a small additional retina with its own separate lens. Lens shapes vary between ovoid ( A. rufus) and spherical ( D. agreste). Our results demonstrate that the camera-type eyes in A. rufus and D. agreste have optical systems that do not allow the production of a sharp image on the retina. The slugs demonstrate negative visually mediated phototactic behaviour, but no polarization sensitivity. Only one aspect of the visual environment, namely the overall distribution of light and dark, seems to be important for these slugs. As the main role of the slugs’ photoreceptors is to monitor environmental brightness and to assist the animal in orientating towards dark places, we conclude that these slugs do not need to perceive sharp images. [ABSTRACT FROM AUTHOR]

The article describes an activity program for elementary, middle school, and high school education science students that asks them to design a research investigation to decide how to measure the success of an adhesive and then compare results for slug slime with those from a commercial glue.

The growth of individual Deroceras agreste slugs from the date of sampling to the end of life has been studied under laboratory conditions. Seven out of 37 mollusks (≈19%) have shown a finite growth pattern, with their body weight reaching a maximum and decreasing thereafter. The data on these mollusks are well approximated by the finite growth equation. Other mollusks have not reached the maximum weight. In many cases, periods of a sharp decrease in body weight with subsequent return to the initial growth curve (compensatory growth) have been observed. In three animals, the growth curve has changed after such a decrease. A comparison of growth parameters in different individuals with the aid of the Ford-Wallford equation has shown that differences between them lack statistical significance. In generally, the slug D. agreste appears to belong to animals with the finite growth pattern. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Plant Protection Research is the property of Institute of Plant Protection and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The sea slug Elysia chiorotica acquires plastids by ingestion of its algal food source Vaucheria litorea. Organelles are sequestered in the mollusc's digestive epithelium, where they photosynthesize for months in the absence of algal nucleocytoplasm. This is perplexing because plastid metabolism depends on the nuclear genome for >90% of the needed proteins. Two possible explanations for the persistence of photosynthesis in the sea slug are (i) the ability of V. Iitorea plastids to retain genetic autonomy and/or (ii) more likely, the mollusc provides the essential plastid proteins. Under the latter scenario, genes supporting photosynthesis have been acquired by the animal via horizontal gene transfer and the encoded proteins are retargeted to the plastid. We sequenced the plastid genome and confirmed that it lacks the full complement of genes required for photosynthesis. In support of the second scenario, we demonstrated that a nuclear gene of oxygenic photosynthesis, psbO, is expressed in the sea slug and has integrated into the germline. The source of psbO in the sea slug is V. litorea because this sequence is identical from the predator and prey genomes. Evidence that the transferred gene has integrated into sea slug nuclear DNA comes from the finding of a highly diverged psbO 3′ flanking sequence in the algal and mollusc nuclear homologues and gene absence from the mitochondrial genome of E. chlorotica. We demonstrate that foreign organelle retention generates metabolic novelty ("green animals") and is explained by anastomosis of distinct branches of the tree of life driven by predation and horizontal gene transfer. [ABSTRACT FROM AUTHOR]

The article discusses a study on a Meghimatium slug called Meghimatium burchi from the watershed of Koan-Tau Mount of Huei-Sun Agriculture Farm in the Central Mountain Range of Taiwan. A description of the jaw, radula and genitalia of M. burchi, with reference to other Meghimatium in the country, is offered. The slug is said to be found in humid, deciduous forests in Taiwan. M. burchi is currently the smallest of all the Taiwanese Meghimatium. One unique character of M. burchi is said to be the expanded proximal ends of the vas deferens (pvd).

The horticultural industry is an important vector of alien snails and slugs. Surveys of nurseries in the Hawaiian Islands recorded 31 terrestrial snail/slug species, all but two of them alien and five previously unrecorded. Individual facilities had 1-17 species. In total, 38 non-native terrestrial snail/slug species have become established, originating globally. Numbers on each island do not reflect numbers of survey locations but rather the total numbers established on each island. Species richness and community composition in nurseries differed significantly among islands and among different-sized nurseries. Certain species were more common on Oahu (main port of entry to Hawaii) so most of these alien species may have been first introduced to Oahu and then spread to other islands. Some of them cause damage in nurseries. Some may cause shipments of nursery products to be rejected when they are inadvertently exported with them. When they are transported to and become established in new areas they may cause agricultural, horticultural and environmental problems. Greater awareness of these species is necessary in the nursery industry and among quarantine officials. [ABSTRACT FROM AUTHOR]

Aim We investigated whether the biogeographical patterns expected if the East African fauna was affected by cycles of contraction to refugia and expansion of ranges, as has been previously hypothesized, can be found in the land snail fauna of rain forests in Uganda. Location The Albertine Rift region and the Lake Victoria forest belt in Uganda. Methods Snails and slugs were sampled in 60 plots in 13 rain forests, and small species were extracted from 5-L leaf litter samples. Relative species richness was calculated by rarefaction. The influence of putative determinants of species richness was examined by bivariate correlation and multiple regression. Clustering and nestedness were tested by Monte Carlo simulations with a null model that considers the range size distribution, the species richness distribution of the forests, and the spatial autocorrelation of the occurrences of each species. Biotic elements were determined by model-based Gaussian clustering. Results A total of 169 land snail species were recorded from 13 Ugandan rain forests. Relative species richness increases with rainfall and altitude, and decreases with evaporation and distance from the putative East Congolian refugia. Mean annual rainfall and distance from the putative East Congolian refugia were included in the best multiple regression model. The distribution areas of the Ugandan land snails are significantly clustered. Two montane, two lowland and a northern biotic element were found. The mean range extension increases with increasing distance from the putative East Congolian refugia. Moreover, the ranges of the Ugandan land snails are significantly nested. The centre of the sets of nested subsets is in the Virunga Mountains, close to the putative East Congolian refugia. Main conclusions The decrease of diversity with increasing distance from the putative East Congolian refugia, the clustering and nestedness of ranges, and the range size increase with increasing distance from the refugia indicate that the East African land snail fauna was affected by cycles of contraction to refugia and expansion of ranges. The significant clustering and nestedness cannot be explained by current environmental conditions. Given the environmental history, it can be supposed that the lowland elements expanded post-glacially, whereas the ranges of the montane species are probably currently contracting. [ABSTRACT FROM AUTHOR]

A method for trace elements (As, Cd, Co, Cr, Cu, Fe, Mn, Pb, U, V and Zn) determination in small amounts of animal tissues using aerosol desolvation and inductively coupled plasma mass spectrometry is presented. A micronebulizer/desolvator system (APEX) and a MicroMist nebulizer fitted to a minicyclonic spray chamber are used for introducing the sample solution in the plasma of a quadrupole ICP-MS espectrometer. The nebulizers are compared with respect to limits of detection (LODs) and sensitivity, showing that both parameters are improved for most investigated elements by using the micronebulizer/desolvator system. Slug specimens were analysed and it was observed that most investigated elements were enriched in the salivatory or digestive glands of the slugs. This work demonstrates the employment of micronebulizer/desolvator systems and ICP-QMS spectrometers are useful for quantification of toxic and essential elements in small amounts of animal tissues. [ABSTRACT FROM AUTHOR]

Oviposition behaviour is important when modelling the population dynamics of many invertebrates. The numbers of eggs laid are frequently used to describe fecundity, but this measure may differ significantly from realised fecundity. Oviposition has been shown to be important when describing the dynamics of slug populations, which are important agricultural pests. The numbers of eggs laid by Deroceras reticulatum and their viability were measured across a range of 16 temperature (4, 10, 15 and 23°C) by moisture (33%, 42%, 53% and 58% by dry soil weight) experimental combinations. A fitted quadratic response surface model was used to estimate how D. reticulatum adjusted its egg laying to the surrounding temperature and moisture conditions, with most eggs being laid at a combination of 53% soil moisture and 18°C. The number and proportion of viable eggs also covaried with temperature and moisture, suggesting that D. reticulatum may alter their investment in reproduction to maximise their fitness. We have shown that the number of viable eggs differs from the total number of eggs laid by D. reticulatum. Changes in egg viability with temperature and moisture may also be seen in other species and should be considered when modelling populations of egg-laying invertebrates. [ABSTRACT FROM AUTHOR]

Terrestrial slugs have the ability to learn and remember a food odor paired with an aversive stimulus. Olfaction in slugs involves the tips of two pairs of tentacles, the superior and the inferior tentacles. Sensory nerves in both pairs of the tentacles transmit olfactory information to the structure in the CNS, the procerebrum where learning and memory formation occur. We investigated the role of each pair of tentacles in odor-aversion learning, and examined the ability of slugs to recall memory after selective surgical amputation. Our results show that memory formation was not altered by the amputation of either one of the pairs before or after odor-aversion learning, while the odor sensibility of the slugs was maintained. These data suggest that either pair of tentacles is sufficient for the acquisition and retrieval of aversive olfactory memory. [ABSTRACT FROM AUTHOR]

Abstract: Nitric oxide (NO) is a key molecule in olfactory information processing across animal species. To gain insight into the genetic basis of NO generation, we investigated the genomic structure of nitric oxide synthase (NOS) in the terrestrial slug Limax because slugs use olfaction as their primary food detection system. The full length cDNA of limNOS encodes a protein consisting of 1632 amino acids that has a PSD-95/discs-large/ZO-1 (PDZ) domain in its N-terminus and 6 other cofactor-binding domains. The limNOS gene consists of 33 exons and spans at least 107 kb of the genome. Almost all the exon–intron boundaries are conserved in Limax and human nNOS and the organization of the Limax genome is more similar to that of humans than to Drosophila, indicating that there was an accelerated evolution of the Drosophila genome during evolution. These results imply that there was a highly conservative selective pressure imposed on NOS gene structure during the evolution of mollusks and vertebrates. [Copyright &y& Elsevier]

We tested the hypothesis that dietary specialization by foraging garter snakes is accompanied by increased assimilation efficiency on specialist prey items. Our comparison included two closely related garter snake species considered to be slug specialists (Thamnophis ordinoides and Thamnophis elegans terrestris), one fish specialist (Thamnophis couchii), and one diet generalist (Thamnophis elegans elegans). Our results suggest that slug specialists have an energetic advantage over non-slugeating snakes when both eat slugs. Slug specialists T. ordinoides and T. e. terrestris both have higher assimilation and net assimilation efficiencies when eating slugs than do generalists T. e. elegans and T. couchii. The slug specialists did not experience decreased efficiency when eating fish. Therefore, there was no apparent digestive trade-off for the slug specialists when eating other prey. [ABSTRACT FROM AUTHOR]

An experiment was performed to study air/water slug frequency in a horizontal clear pipe by means of visual inspection and differential pressure measurement in the range of 0-1/s. Results showed that a simplified model for slug pressure drop allowed the differential pressure data to compare favorably with visual observations for slug frequency. it was concluded that this technique gives a proper estimation of slug frequency, given only basic flow information. it is recommended that this technique be used when constrained to differential pressure or used to analyze existing differential pressure data. [ABSTRACT FROM AUTHOR]

Slug (Snail2) is a member of the Snail family of zinc-finger transcription factors with regulatory functions in development, tissue morphogenesis, and tumor progression. Little is known about Slug in normal adult tissue; however, a role for Slug in the skin was suggested by our previous observations of Slug expression in normal murine keratinocytes and Slug induction at wound margins. To study the impact of Slug in the skin, we compared patterns of gene expression in epidermis from Slug-null and wild-type mice. A total of 139 genes had significantly increased, and 109 genes had significantly decreased expression in Slug knockout epidermis. Altered expression of selected genes in Slug knockout epidermis was validated by real-time PCR and immunohistochemistry. Previously reported Slug targets were identified, in addition to novel genes, including cytokeratins, adhesion molecules, and extracellular matrix components. Functional classification of altered gene expression was consistent with a role for Slug in keratinocyte development and differentiation, proliferation, apoptosis, adhesion, motility, as well as angiogenesis and response to environmental stimuli. These results highlight the utility of genetic models to study the in vivo impact of regulatory factors in unperturbed skin and suggest that Slug has significant activities in the adult epidermis.Journal of Investigative Dermatology (2008) 128, 361–369; doi:10.1038/sj.jid.5700990; published online 19 July 2007 [ABSTRACT FROM AUTHOR]

Background: The bacterium Moraxella osloensis is a mutualistic symbiont of the slug-parasitic nematode Phasmarhabditis hermaphrodita. In nature, P. hermaphrodita vectors M. osloensis into the shell cavity of the slug host Deroceras reticulatum in which the bacteria multiply and kill the slug. As M. osloensis is the main killing agent, genes expressed by M. osloensis in the slug are likely to play important roles in virulence. Studies on pathogenic interactions between bacteria and lower order hosts are few, but such studies have the potential to shed light on the evolution of bacterial virulence. Therefore, we investigated such an interaction by determining gene expression of M. osloensis in its slug host D. reticulatum by selectively capturing transcribed sequences. Results: Thirteen M. osloensis genes were identified to be up-regulated post infection in D. reticulatum. Compared to the in vitro expressed genes in the stationary phase, we found that genes of ubiquinone synthetase (ubiS) and acyl-coA synthetase (acs) were up-regulated in both D. reticulatum and stationary phase in vitro cultures, but the remaining 11 genes were exclusively expressed in D. reticulatum and are hence infection specific. Mutational analysis on genes of protein-disulfide isomerase (dsbC) and ubiS showed that the virulence of both mutants to slugs was markedly reduced and could be complemented. Further, compared to the growth rate of wild-type M. osloensis, the dsbC and ubiS mutants showed normal and reduced growth rate in vitro, respectively. Conclusion: We conclude that 11 out of the 13 up-regulated M. osloensis genes are infection specific. Distribution of these identified genes in various bacterial pathogens indicates that the virulence genes are conserved among different pathogen-host interactions. Mutagenesis, growth rate and virulence bioassays further confirmed that ubiS and dsbC genes play important roles in M. osloensis survival and virulence, respectively in D. reticulatum. [ABSTRACT FROM AUTHOR]

Abstract: Immunological and behavioural studies have shown that adult carabids such as Pterostichus melanarius (Illiger) are predators of slugs. However, little is known about the trophic interactions and spatial ecological of carabid larvae in the soil. Having demonstrated that the larvae will readily consume slugs in the laboratory and can reduce slug numbers in semi-field soil microcosms, experiments were designed to test the hypothesis that the larvae respond to chemical cues from their prey. Electroantennograms (EAG) showed that P. melanarius larvae were able to detect the presence of a range of volatiles using olfactory cues. There were significant EAG responses to both live and dead slugs (Derocerus reticulatum) and Diptera larvae (Calliphora sp.). Dead prey did not induce a response that was significantly different from that to live prey. Behavioural bioassays demonstrated attraction to odours from both live and dead slugs beneath the soil, but when offered a choice there was (after 6h) a significantly greater attraction to live slugs. These results demonstrate for the first time that P. melanarius larvae appear to use olfactory cues to locate their subterranean prey. [Copyright &y& Elsevier]

Slugs, Arion ater (L), have been proposed as sentinel organisms to assess soil health. In slugs under the influence of pollutants, digestive cell loss and the concomitant increase of excretory cells of the digestive gland have been described. The aim of the present work was to determine up to what extent digestive cell loss affects biomarkers and whether the affectation is reversible after exposure to a mixture of metal and organic pollutants. Slugs were dosed with a mixture of cadmium and kerosene in the food for 27 days. Apart from chemical analyses, the volume density of black silver deposits (VvBSD) after autometallography, and acyl-CoA oxidase (AOX) activity were used as biomarkers of exposure to metals and organic compounds, respectively. As effect biomarkers, changes in the volume density of the cell types that constitute the digestive gland epithelium were calculated. Proliferating cells were identified by means of bromodeoxyuridine (BrdU) immunohistochemistry. Results revealed that the mixture of pollutants provoked an increase in VvBSD and AOX activity and a decrease in the number of digestive cells. These changes had no effect in the digestive gland accumulation capacity or in the effect and exposure biomarkers employed. BrdU-labelling showed that exposure to pollutants provoked an enhanced digestive cell proliferation. [Copyright &y& Elsevier]

Freezing survival was assessed in three species of terrestrial slugs, a holarctic but native North American species, Deroceras laeve, and two species introduced from Europe, D. reticulatum and Arion circumscriptus. The introduced species showed very poor freezing survival. Supercooling points of the introduced species were quite high (∼−3°C) and their freezing survival was very poor, limited to short-term freezing at −1.2 to −1.5°C and low ice contents (23–44%). D. laeve showed a significant elevation of supercooling point between slugs collected in the autumn (−4.8°C ± 0.5) and those collected early in the spring (−3.1°C ± 0.4). This species also showed substantial freezing survival which was greater for spring-collected slugs (100% survival of 1 h freezing at −2°C with an ice content of 65%) than for autumn animals (100% survival for 1 h at −1°C with ∼40% ice). Carbohydrate and amino acid responses to freezing and anoxia exposures were compared in the two Deroceras species. D. laeve showed a strong hyperglycemic response to freezing, a 100-fold increase in glucose levels that suggested that glucose may have a cryoprotective function in this species. D. reticulatum did not accumulate glucose and neither species produced glycerol or lactate. Both species showed typical responses to anoxia (aspartate and glutamate catabolism, alanine and succinate accumulation) and D. laeve also showed this pattern during freezing, suggesting a natural switch to anaerobiosis to support freezing survival. [ABSTRACT FROM AUTHOR]

Abstract: We describe the epidermal mucus of two types of terrestrial invertebrates: free-living flatworms (Tricladida: Terricola), and the slug Lehmannia valentiana (Gastropoda: Pulmonata). Both exhibited similar dry shear strengths (1.4–1.7 MPa). In denaturing gel electrophoresis, the protein fraction of flatworm mucus migrated mainly as a broad band (200–300 kDa). Slug mucus had a higher protein content than flatworm mucus but it contained more carbohydrate than protein, mainly as large heparan sulfate-like glycosaminoglycans. Proteins and glycosaminoglycans were both essential for the mechanical integrity of the slug hydrogel. The protein fraction of slug mucus contained ∼12 larger proteins (30–300 kDa) and ∼6 smaller ones (10–28 kDa). Complete cDNA clones were obtained for the slug mucus 40 kDa protein (Sm40; Genbank accession EF634345 ) and 85 kDa protein (Sm85; Genbank accession EF634346 ). Both proteins contain EGF-like repeats and von Willebrand A-domains, and therefore resemble vertebrate matrilins. Many of the larger slug mucus proteins appear to contain A-domains, and these may play a role in the unusual rheological properties of gastropod mucus. [Copyright &y& Elsevier]

The semi-slug Parmarion cf. martensi Simroth, 1893, was first discovered on O'ahu, Hawai'i, in 1996 and then on the island of Hawai'i in 2004. This species, which is probably native to Southeast Asia, is abundant in eastern Hawai'i Island, reportedly displacing the Cuban slug, Veronicella cubensis (Pfeiffer, 1840), in some areas. A survey in July-August 2005 found P. cf. martensi primarily in the lower Puna area of Hawai'i Island, with an isolated population in Kailua-Kona (western Hawai'i Island). It is now established in commercial papaya plantations, and survey participants reported it as a pest of lettuce and papaya in home gardens. Survey respondents considered P. cf. martensi a pest also because of its tendency to climb on structures where it deposits its feces and because of its potential to transmit disease. Individuals of this species were found to carry large numbers of infective third-stage larvae of the nematode Angiostrongylus cantonensis (Chen, 1935), the causative agent of human angiostrongyliasis and the most common cause of human eosinophilic meningoencephalitis. Using a newly developed polymerase chain reaction test, 77.5% of P. cf. martensi collected at survey sites were found infected with A. cantonensis, compared with 24.3% of V. cubensis sampled from the same areas. The transmission potential of this species may be higher than that for other slugs and snails in Hawai'i because of the high prevalence of infection, worm burdens, and its greater association with human habitations, increasing the possibility of human-mollusk interactions. [ABSTRACT FROM AUTHOR]

Grassland conservation headlands were established on intensively managed grassland fields on four farms in Scotland. Vegetation composition and structure, invertebrate activity density (as measured by pitfall trapping), ground beetle assemblage structure and bird utilisation in these grassland conservation headlands were compared with conventional headlands (i.e. areas of headland managed as per the rest of each field). Increased activity densities of Arionidae slugs, heteropteran bugs and homopteran bugs were recorded in the grassland conservation headlands when compared to the conventional headlands. Despite an increase in potential prey, very few birds were observed in the study fields, and the grassland conservation headlands were no richer in birds than the conventional headlands. The vegetation of the grassland conservation headlands was longer and denser than the conventional headland. Hence, while the activity density of potential prey was greater in the conservation headlands, accessibility to prey and foraging conditions for birds may have been poorer. While there was evidence that the ground beetle Nebria brevicollis utilised the grassland conservation headland as a summer aestivating site, the activity density of ground beetles in general was found to be lower in the conservation headlands than the conventional headlands. For grassland conservation headlands to reach their full potential, it is suggested that additional measures are taken to open the vegetation structure of such headlands. [Copyright &y& Elsevier]

Individual growth of gray garden slug Deroceras reticulatum was studied under laboratory conditions in the period from collection to death. The studied population demonstrated different patterns of growth. Three groups of slugs were recognized: (1) slugs that reached the maximum weight after 4 months of raring, after which their weight rapidly decreased (the life span in culture was 6–7 months); (2) slugs that have not reached the maximum weight until death (the life span was 6–7 months); (3) slugs that reached the maximum weight after 7–8 months, after which their weight oscillated with a trend to decrease (the life span was about 10 months). The obtained data were approximated by the equation of finite growth. [ABSTRACT FROM AUTHOR]

An increasing number of exotic terrestrial planarian species have established populations worldwide. In North America, the most prominent invasive flatworms are three members of the broadhead planarian genus Bipalium. Herein we report observations on the morphology, predatory behavior, and reproduction of Bipalium of cf. vagum, new to this continent and report its occurrence in Florida and Texas. Individuals of this species have a distinctive combination of head shape and pattern of dark dorsal pigmentation (large head spots, complete collar, and prominent median stripe) that distinguishes them from other members of the genus. Although the other North American species of Bipalium feed on earthworms, B. cf. vagum feeds exclusively on terrestrial mollusks. Their predatory behavior includes following mucus trails and subduing the prey by capping the prey's head with the flatworm's anterior end and wrapping the prey's foot in the body of the planarian. Members of this species reproduce via egg capsules that contain small numbers of offspring. Because this is the first land planarian reported in North America that is a predator of mollusks, native land snails and slugs are unlikely to have effective defenses against it. Therefore, we should continue to monitor its geographic spread and potential ecological impact. [ABSTRACT FROM AUTHOR]

The effects of acid deposition on soil calcium (Ca), and in turn on land snail populations, have been of heightened concern for several decades. We compiled a 10 year record (1997–2006) of gastropod abundance on two small watersheds at the Hubbard Brook Experimental Forest, one of which was treated with a Ca addition in 1999. In years 3–7 post Ca addition, snail abundance in the treated watershed was 73% higher than in the reference area (p < 0.001); there was no significant difference in the 3 years prior to treatment, and no significant difference in slug abundance in any year. We analyzed relationships between snail density and microsite spatial variation in leaf-litter Ca concentration, litter-layer thickness, tree species composition, slope, dead wood, and forest-floor light level. We found that snail abundance was significantly correlated with litter Ca concentration (p < 0.001) and negatively correlated with the importance value of American beech (p = 0.05). Isotopic-tracer analysis indicated that, on average, 76% of Ca in snail shells 5 years post treatment was derived from the added Ca. However, interannual variation in snail numbers indicates that other factors beyond available Ca have a strong influence on snail abundance. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Plant Protection Research is the property of Institute of Plant Protection and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Quantitative imaging analysis of endogenous an exogenous elements throughout entire organisms is required for studies of bioavailability, transport processes, distribution, contamination and to monitor enviromnental risks using indicator organisms. An imaging mass spectrometric technique using laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) was developed to analyze selenium and metal distributions in longitudinal sections (thickness, 100 μm) of entire slugs (genus anon). Slugs were fed with either a placebo or solutions containing 1000 μg mL-1 Se. Samples (raster area, 25 mm × 45 mm) were scanned together with synthetic matrix-matched standards with a focused beam of a Nd:YAG laser (wavelength, 266 nm; diameter of laser crater, 50 μm; laser power density, 3 × 109 W cm-2) in a large laser ablation chamber. The ablated material was transported with argon as carrier gas to the ICP ion source at a double focusing sector field ICPMS. Ion intensities of selenium (78Se+, 82Se+) were measured together with 13C+, 63Cu+, and 64Zn+ within the entire tissue section. The regression coefficient of the calibration curve was 0.998. Inhomogeneous distributions for Se but also for C, Cu, and Zn were found. Selenium was enriched in the kidney (150 μg g-1 in Se-treated animals versus 15 μg g-1 in the placebo-treated animal, respectively) and in the digestive gland (200 μg g-1 versus 25 μg g-1). Highest Se concentrations were detected in the gut of Se-treated slugs (250 μg g-1), and additional Se occurred in the skin of these animals. Cu was enriched in the heart and the mucous ventral skin. Interestingly, in addition to the localization in the digestive gland, Zn was detected only in the dorsal skin but not the ventral skin. The developed analytical technique allows the quantitative imaging of selenium together with selected metals in thin sections of biological tissue with limits of detection at the submicrogram per gram range. [ABSTRACT FROM AUTHOR]

The highly invasive giant knotweed ( Reynoutria spp .) often displaces nettle ( Urtica dioica) dominated stands in European floodplains. Urtica-dominated stands differ from the monospecific Reynoutria stands in plant species richness and stand structure. We thus hypothesize that Reynoutria invasion profoundly alters ecosystem structure and function, with negative effects cascading up through the food chain. We performed a paired sampling design in six sites belonging to two different locations and studied effects on the soil and the litter-dwelling fauna. Reynoutria stands differed in habitat structure and were characterized by decreased soil pH and potassium depletion. The faunal analysis is based on model groups of herbivore generalists (Gastropoda), detritivores (Isopoda and Diplopoda), and predators (Opiliones). The gastropod assemblages from Reynoutria stands were severely impoverished subsets of those from Urtica stands with reduced densities, species richness and diversity. In general, snails were more sensitive to Reynoutria invasion than slugs such as the invasive Arion ' lusitanicus’. Among detritivores, the abundance of the Isopoda decreased, whereas Diplopoda were not affected by Reynoutria invasion. Yet, the relative abundance of detritivores was significantly higher within the Reynoutria stands. Abundance, species richness and diversity of the predatory Opiliones were higher in the relatively sparse Reynoutria stands. We conclude that ecosystem changes associated with Reynoutria invasion are characterized by shifts from a plant-based to a detritus-based food chain and that Reynoutria invasion primarily enhances predators that profit from the simplified vegetation structure. [ABSTRACT FROM AUTHOR]

Seasonal maturation of the gonad (hermaphrodic gland) was examined in the terrestrial slug Lehmannia valentiana in Osaka, Japan. The ratio of the gonad weight to body weight was low in June–September, rapidly increased in October, and gradually decreased thereafter. In May–September, most slugs had only spermatogonia and spermatocytes, and all slugs had mature sperms in October–April. The oocyte size increased in September and large oocytes were observed in late October–April. Under natural temperature and photoperiodic conditions in Osaka, slugs laid eggs in early November–May. Therefore, this species reproduces from late autumn to spring, in contrast to many terrestrial slugs. In January–early February, however, the number of laid eggs was small and oviposition activity showed a bimodal seasonal pattern. In contrast, the hatching pattern was unimodal and most hatching was observed in spring. After a 1-h exposure to 33°C, the survival rate was 100% in juvenile slugs but 0% in eggs. Although hatching success was >85% at 15°–20°C, no eggs hatched when they were maintained at 25°C. The heat susceptibility of eggs in this species may be one of the key factors restricting oviposition from late autumn to spring. [ABSTRACT FROM AUTHOR]

This study investigated the genetic and chemical basis of resistance of Pinus sylvestris seedlings to herbivory by a generalist mollusc, Arion ater. Using feeding trials with captive animals, we examined selective herbivory by A. ater of young P. sylvestris seedlings of different genotypes and correlated preferences with seedling monoterpene levels. We also investigated the feeding responses of A. ater to artificial diets laced with two monoterpenes, Δ3-carene and α-pinene. Logistic regression indicated that two factors were the best predictors of whether seedlings in the trial would be consumed. Individual slug variation (replicates) was the most significant factor in the model; however, α-pinene concentration (also representing β-pinene, Δ3-carene and total monoterpenes due to multicollinearity) of needles was also a significant factor. While A. ater did not select seedlings on the basis of family, seedlings not eaten were significantly higher in levels of α-pinene compared to seedlings that were consumed. We also demonstrated significant genetic variation in α-pinene concentration of seedlings between different families of P. sylvestris. Nitrogen and three morphological seedling characteristics (stem length, needle length and stem diameter) also showed significant genetic variation between P. sylvestris families. Artificial diets laced with high (5 mg g−1 dry matter) quantities of either Δ3-carene or α-pinene, were eaten significantly less than control diets with no added monoterpenes, supporting the results of the seedling feeding trial. This study demonstrates that A. ater selectively feed on P. sylvestris seedlings and that this selection is based, in part, on the monoterpene concentration of seedlings. These results, coupled with significant genetic variation in α-pinene concentration of seedlings and evidence that slug herbivory is detrimental to P. sylvestris fitness, are discussed as possible evidence for A. ater as a selective force on the evolution of defensive chemistry in P. sylvestris. [ABSTRACT FROM AUTHOR]

Abstract: Epithelial cell migration during corneal wound re-epithelialization shares features with the developmental process of epithelial-mesenchymal transition (EMT) modulated by Snail family transcription factors, including Slug. Our studies demonstrated that Slug expression was enhanced at sites of epithelial cell migration at the margins of normally healing corneal wounds in dogs, but significantly decreased at the margins of non-healing canine corneal erosions. Increased Slug expression was associated with internalization of E-cadherin and ß-catenin from the cell membrane and with enhanced expression of smooth-muscle-specific α-actin, tropomyosin, and matrix metalloproteinases at wound margins. Enhanced Slug expression in corneal explants due to an adenoviral expression construct or to oxytetracycline treatment resulted in significantly higher rates of corneal epithelial cell migration. Oxytetracycline appeared to act by stimulating transforming growth factor-ß activity, thus increasing Slug expression and enhancing corneal epithelial migration. These findings highlight the similarities between epithelial migration during EMT and during successful corneal wound healing, support an important role for the Snail family in the process, and indicate that modulating Slug expression may be clinically useful in treating non-healing corneal wounds. [Copyright &y& Elsevier]

The original description of the slugs Arion ( Carinarion) fasciatus, Arion ( Carinarion) silvaticus and Arion ( Carinarion) circumscriptus was based on subtle differences in body pigmentation and genital anatomy. However, body pigmentation in these slugs may be influenced by their diet, whereas the genital differences between the species could not be confirmed by subsequent multivariate morphometric analyses. Hence, the status of the three nominal morphospecies remains controversial, with electrophoretic studies based on albumen gland proteins and allozymes also providing conflicting results. These studies suggested that Carinarion species are difficult to reconcile with the biological species concept because there is evidence of interspecific hybridization in places where these predominantly self-fertilizing slugs apparently outcross. Therefore, in the present study, the three Carinarion species are evaluated under a phylogenetic species concept, using nucleotide sequences of the nuclear ribosomal internal transcribed spacer 1 (ITS-1) and the mitochondrial 16S rDNA. ITS-1 showed no species specific variation. However, 16S rDNA yielded five haplotype groups. Three of these grouped haplotypes by species, whereas the two others joined haplotypes of different species and included all haplotypes that were shared by species (22% of all haplotypes). Hence, the three nominal Carinarion species appear to be inconsistent with a phylogenetic species concept. The present data also confirmed that North American Carinarion populations are genetically impoverished and may be not sufficiently representative with respect to the taxonomy of Carinarion. In conclusion, we currently regard Carinarion as a single species-level taxon, whose taxonomically deceiving, correlated phenotypic and genetic intraspecific variation is caused by sustained self-fertilization. © 2006 The Linnean Society of London, Biological Journal of the Linnean Society, 2006, 89, 589–604. [ABSTRACT FROM AUTHOR]

We develop a novel, nonlinear structured population model for the slug Deroceras reticulatum, a highly significant agricultural pest of great economic impact, in both organic and non-organic settings. In the absence of seasonal variations, we numerically explore the effect of life history traits that are dependent on an individual's size and measures of population biomass. We conduct a systematic exploration of parameter space and highlight the main mechanisms and implications of model design. A major conclusion of this work is that strong size dependent predation significantly adjusts the competitive balance, leading to non-monotonic steady state solutions and slowly decaying transients consisting of distinct generational cycles. Furthermore, we demonstrate how a simple ratio of adult to juvenile biomass can act as a useful diagnostic to distinguish between predated and non-predated environments, and may be useful in agricultural settings. [ABSTRACT FROM AUTHOR]

On starvation, Dictyostelium cells form a terminally differentiated structure, known as the fruiting body, which comprises stalk and spore cells. Their precursors–prestalk and prespore cells–are spatially separated and accessible in a migratory structure known as the slug. This simplicity and manipulability has made Dictyostelium attractive to both experimental and theoretical developmental biologists. However, this outward simplicity conceals a surprising degree of developmental sophistication. Multiple prestalk subtypes are formed and undertake a co-ordinated series of morphogenetic cell movements to generate the fruiting body. This review describes recent advances in understanding the signalling pathways that generate prestalk-cell heterogeneity, focusing on the roles of the prestalk-cell inducer differentiation-inducing factor-1 (DIF-1), the tip inducer cAMP and the transcription factors that mediate their actions; these include signal transducer and activator of transcription (STAT) proteins, basic leucine zipper (bZIP) proteins and a Myb protein of a class previously described only in plants. [ABSTRACT FROM AUTHOR]

Slug, a member of the Snail family of transcription factors, plays a crucial role in the regulation of epithelial-mesenchymal transition (EMT) by suppressing several epithelial markers and adhesion molecules including E-cadherin. Recently, several studies have reported Slug to be expressed in breast carcinoma, oesophageal carcinoma accompanied with shorter survival. In this study, we first investigated expression of Slug mRNA in five colorectal carcinoma cell lines by reverse transcription-polymerase chain reaction. Furthermore, we investigated Slug and E-cadherin expression by immunohistochemistry in 138 patients with colorectal carcinoma. Slug mRNA was clearly expressed in four out of five colorectal carcinoma cell lines. Positive expression of Slug and E-cadherin was observed in 37 and 58% of cases, respectively. The positive expression of Slug was significantly associated with Dukes stage and distant metastasis (P = 0.0027 and 0.0007), and the positive expression of Slug had a significant impact on patient overall survival (P < 0.0001, log-rank test). Moreover, patients with positive expression of Slug and reduced expression of E-cadherin showed the worst prognosis (P < 0.0001, log-rank test). Multivariate analysis indicated that Slug expression was an independent prognostic factor. These results suggest that positive Slug expression in colorectal carcinoma patients may become a significant parameter of poor prognosis. [ABSTRACT FROM AUTHOR]

Abstract: The Slug Mucosal Irritation test seems to be a promising method for the evaluation of the local tolerance of products applied to the mucosa. Furthermore, the Slug Mucosal Irritation test is a reliable method to classify chemicals accurately into three eye irritation categories based on the mucus production and the score for tissue damage. Until now the slug Arion lusitanicus collected in Belgium was always used as test organism. The present study investigated the effects of the slug population and species on the end points of the test and on the eye irritation classification. For this purpose, the eye irritation/damage test procedure and eye reference chemicals were used. Comparison of the results of one Belgian and two Swiss A. lusitanicus populations indicated that the geographic and ecological origins of slug populations did neither influence the mucus production, nor the score for tissue damage. Slug species-specific effects on the test end points were investigated by comparing the data of Belgian Limax flavus with corresponding data of Belgian A. lusitanicus. L. flavus produced more mucus than A. lusitanicus, so that the mucus production cut-off values had to be increased. Therefore, the results indicated that the test procedure and prediction model have to be optimised and validated, if other slug species are used instead of A. lusitanicus. [Copyright &y& Elsevier]

Tritonia diomedea is a useful neuroethological model system that can contribute to our understanding of the neural control of navigation. Prior work on both sensory and locomotory systems is complemented by recent field experiments, which concluded that these animals primarily use a combination of odours and water flow as guidance cues. We corroborate these field results by showing similar navigation behaviours in a flow tank. Slugs crawled upstream towards both prey and conspecifics, and turned downstream after crawling into a section of the flow tank downstream of a predator. Controls without upstream odour sources crawled apparently randomly. We then tested whether these behaviours depend on odours detected by the rhinophores. Outflow from a header tank was used to generate prey, predator and unscented control odour plumes in the flow tank. Slugs with rhinophores crawled upstream towards a prey odour plume source, turned downstream in a predator odour plume, and showed no reaction to a control plume. Slugs without rhinophores behaved similarly to controls, regardless of odour plume type. Finally, we used extracellular recordings from the rhinophore nerve to demonstrate that isolated rhinophores are chemosensitive. Afferent activity increased significantly more after application of all three odour types than after unscented control applications. Responses were odour specific. We conclude that rhinophores mediate orientation to flow, and suggest that future work should focus on the integration of mechanosensation and chemosensation during navigation in T. diomedea. [ABSTRACT FROM AUTHOR]

Progress in understanding sensory and locomotory systems in Tritonia diomedea has created the potential for the neuroethological study of animal navigation in this species. Our goal is to describe the navigational behaviors to guide further work on how the nervous system integrates information from multiple senses to produce oriented locomotion. Observation of T. diomedea in its habitat has suggested that it uses water flow to navigate relative to prey, predators, and conspecifics. We test these hypotheses in the field by comparing slug orientation in time-lapse videos to flow direction in circumstances with and without prey, predators, or conspecifics upstream. T. diomedea oriented upstream both while crawling and after turning. This trend was strongest before feeding or mating; after feeding or mating, the slugs did not orient significantly to flow. Slugs tamed downstream away from an upstream predator but did not react in control situations without an upstream predator. These data support the hypothesis that T. diomedea uses a combination of odors (or some other cue transported downstream) and water flow to navigate relative to prey, predators, and conspecifics. Understanding the context-dependent choice between upstream and downstream crawling in T. diomedea provides an opportunity for further work on the sensory integration underlying navigation behavior. [ABSTRACT FROM AUTHOR]

By comparing two species of cellular slime molds that have stalkless migration stages it is possible to gain interesting insights into how the cells move. In contrast to the familiar behavior of Dictyostelium discoideum, Dictyostelium polycephalum slugs can travel greater distances through soil and even can migrate through agar. In addition to the interest in the differences, these differences shed light on the mechanism of slug movement. Unlike D. discoideum, D. polycephalum does not have prestalk and prespore zones and severed sections of any part of these slugs move at a rate proportional to their length. This leads to the hypothesis that longer slugs move faster because the amoebae aligned along the inside of the slime sheath each contribute a forward push and the more extended the amoebae line is the faster the slug moves. [ABSTRACT FROM AUTHOR]

Abstract: The Iberian Slug, Arion lusitanicus Mabille (Stylomatophora: Arionidae), has developed into a destructive pest in Swedish gardens and orchards over the past 10–20 years. Many attempts to eradicate this pest have been made using a variety of different methods. The aim of this study was to investigate the effectiveness of two different types of homemade traps made from simple, inexpensive materials (plastic PET bottle or an ice-cream box) compared to one type of commercially sold trap (Slugtrap® IT-PAC AB, Sweden) used with bait and beer as attractants. Experiments were carried out on a private property outside Lund, Sweden, over a period of 7 days. The results showed that a homemade trap, i.e. a box trap, can be as efficient as a commercial trap, particularly due to their similar design. In contrast, the homemade bottle trap was not very successful. Additionally, it was discovered that the bait used in the commercial traps did not increase the number of slugs trapped. It was concluded that the beer was the main slug attractant. Ultimately this study suggests a low-cost alternative for small scale to the rather expensive commercially sold traps. [Copyright &y& Elsevier]

The slug, Deroceras reticulatum, is one of the most important pests of agricultural and horticultural crops in UK and Europe. In this paper, a spatially explicit individual based model (IbM) is developed to study the dynamics of a population of D. reticulatum. The IbM establishes a virtual field within which slug spatial dynamics and changes in abundance were simulated. The strong dependence of slug behaviour on environmental conditions is built into the model, which is based upon previous work on the environmental dependence of slug population dynamics. The simulation results show that the IbM described well changes in the slug population. The IbM proved capable of describing slug populations over 3.5 years, including the presence, magnitude and duration of D. reticulatum population crashes within this period. Moreover, the model was capable of reproducing slug population dynamics at two sites, with distinct weather and some 100km apart, with minor changes in initialisation values but no change in model structure and parameter values. A study of field heterogeneity, which might simulate various field designs, indicated the importance of spatial structuring to slug population dynamics and the utility of the IbM for simulating a range of potential spatial management treatments for slug control to maximise crop yield. This IbM system performs well and is currently being used as part of an integrated approach to predict slug population dynamics and control in the UK. [Copyright &y& Elsevier]

Field and laboratory studies were performed to determine whether slugs could act as novel vectors for pathogen (e.g., Escherichia coli O157) transfer from animal feces to salad vegetables. Escherichia coli O157 was isolated from 0.21% of field slugs from an Aberdeenshire sheep farm. These isolates carried the verocytotoxin genes (vt1 and vt2) and the attaching and effacing gene (eae), suggesting that they are potentially pathogenic to humans. Strain typing using multilocus variable number tandem repeats analysis showed that slug and sheep isolates were indistinguishable. Laboratory experiments using an E. coli mutant resistant to nalidixic acid showed that the ubiquitous slug species Deroceras reticulatum could carry viable E. coli on its external surface for up to 14 days. Slugs that had been fed E. coli shed viable bacteria in their feces with numbers showing a short but statistically significant linear log decline. Further, it was found that E. coli persisted for up to 3 weeks in excreted slug feces, and hence, we conclude that slugs have the potential to act as novel vectors of E. coli O157. [ABSTRACT FROM AUTHOR]

In the final stages of an elaborate courtship, many slugs and snails shoot calcareous ‘love’ darts into each other. While darts improve the reproductive success of the shooter, by promoting sperm survival in the recipient, it is unclear why some species have darts and others do not. In fact, dart use has barely been studied, except in the garden snail Cantareus aspersus (Helix aspersa). An evolutionary approach was therefore taken to attempt to understand the origin and use of darts, by investigating mating behaviour in a wide range of species. The prediction was that, because darts could have arisen out of an escalating cycle of sperm digestion and investment in sperm, then darts should be found in taxa that enforce simultaneous reciprocity during mating. Likewise, they should not be found in taxa that mate unilaterally, because the co-evolutionary cycle is absent or reduced. Mating behaviour in 60 genera (28 families) of land snails and slugs was recorded, and compared against dart use across the whole of a stylommatophoran phylogeny. ‘Face-to-face’ simultaneous reciprocal-mating behaviour is restricted to three monophyletic groups of snails and slugs, and dart-bearing species are a subset within the same clades, which suggests a link, though not necessarily a causal one. As yet, we are unable to quantify the extent to which darts or mating behaviour, as well as several other correlated characters, are determined by common ancestry or regimes of natural or sexual selection, because the current phylogeny lacks resolution. However, the results emphasize that to understand the use of darts, then data are required from a wide range of species. The realization that several characters are correlated may stimulate further research, and could eventually lead to some testable models for dart and mating behaviour evolution. [ABSTRACT FROM AUTHOR]

Gut-content analyses using molecular techniques are an effective approach to quantifying predator–prey interactions. Predation is often assumed but scavenging is an equally likely route by which animal DNA enters the gut of a predator/scavenger. We used PCR (polymerase chain reaction) to detect scavenged material in predator gut homogenates. The rates at which DNA in decaying slugs (Mollusca: Pulmonata) and aphids (Homoptera: Aphididae) became undetectable were estimated. The detectability of DNA from both carrion types in the guts of the generalist predator Pterostichus melanarius (Coleoptera: Carabidae) was then determined. The effects of carrion age and weight, as well as beetle sex, on detection periods, were quantified. Laboratory trials measured prey preference of beetles between live and decaying prey. Further experiments measured, for the first time, feeding by P. melanarius on dead slugs and aphids directly in the field. In both field and laboratory, P. melanarius preferentially fed on dead prey if available, but preference changed as the prey became increasingly decayed. Disappearance rates for slug carrion in wheat fields and grasslands were estimated and P. melanarius was identified as the main scavenger. Comparison of the retention time for dead slugs in the field, with the detection period for decaying slug material in the guts of the predators, showed that PCR-based techniques are not able to distinguish between predated and scavenged food items. This could potentially lead to overestimation of the impact of predation on slugs (and other prey) by carabids. Possible implications of facultative scavenging by invertebrate predators for biocontrol and food-web research are discussed. [ABSTRACT FROM AUTHOR]

1. Generalist herbivores such as slugs have the potential not only to reduce plant density and biomass, but also to alter species diversity within vegetation. Their impact on species diversity may be either negative, if they concentrate feeding on less abundant plant species, or positive, if they feed on the most abundant species.2. This study investigated the influence of slugs on plant species diversity in experimental swards produced by sowing aLolium perenne/Trifolium repensseed mixture in field plots with a large seed bank of mainly arable species. Half of the plots were grazed byArion lusitanicusMabille. Plant cover, above-ground biomass and number of plant species were measured over a 3-year period.3. Vegetation cover increased in the control plots from 50% in the first year to 90% in the third year. Cover was significantly lower in the slug plots in the first year (>22%), while there were only small differences between treatments in the third year. Slugs reduced total above-ground biomass by>25% in both the first and third years.4. Slugs had a negative impact on plant species diversity in the first year, particularly by reducing forb species. In contrast, plant species diversity after 3 years was higher in the slug plots than in the controls, because of the higher number of forb species. Under slug grazing, the biomass and cover of annual and palatable species were reduced, but not the numbers of these species.5. Our results suggest that slugs can have a significant effect on plant species diversity in plant communities, but that the direction of the effect changes during the course of succession. In the earliest stages, when most species are present as seedlings or juveniles, slug grazing leads to reduced species diversity because favoured species are eliminated. In closed vegetation, in which competitive interactions are important, slugs may reduce the dominance of the more competitive species and thus provide gaps in which plants can establish from seed. As a consequence, slugs tend to cause an increase in plant species diversity, and may also reduce the rate of successional change by promoting the persistence of annual species.Functional Ecology(2005)19, 291–298doi: 10.1111/j.1365-2435.2005.00960.x [ABSTRACT FROM AUTHOR]

Intraspecific phylogeographical patterns largely depend on the life history traits of a species. Especially species with a high degree of cold tolerance, limited requirements towards habitat preferences, and relatively low active dispersal capacities may have responded in a different way to the Pleistocene climatological fluctuations than the majority of taxa studied so far. To evaluate this possibility, we studiedArion fuscus(Müller, 1774), a common and widespread European terrestrial slug, from 88 locations (N = 964). Sequence variation was assessed for fragments of the mitochondrial16S rDNAandCOIgenes by means of single-strand conformation polymorphisms (SSCP) and subsequent DNA sequencing. Additionally, eight allozyme loci were scored in 843 individuals. Phylogenetic analysis revealed the presence of two major evolutionary lineages, one in the Balkan region and another in the Alps and the rest of Europe. The sequence divergence between the two lineages was limited (3.3%), but gene flow between the regions was absent, suggesting that the two regions have been isolated since the late Pliocene or early Pleistocene. Allozyme differentiation among geographical regions and mitochondrial DNA (mtDNA) lineages was low. The geographical patterns observed in our data showed that (i) haplotype and nucleotide diversities are very low in northern Europe, suggesting that single haplotypes rapidly colonized large areas; (ii) recently expanded haplotype clades have restricted distribution ranges, suggesting that current gene flow is low; and (iii) genetic diversity in the Alps is much higher than in other regions and estimated past gene flow from the Eastern Alps to other regions was high, suggesting that this was a refugial zone during the Pleistocene. This full-range phylogeography suggests the existence of an alternative refugial zone, situated north of the refugial areas currently recognized in most other taxa. [ABSTRACT FROM AUTHOR]

We incorporate a linear estimate of casing friction into the analytical slug test theory of Springer and Gelhar (1991) for high permeability aquifers. The modified theory elucidates the influence of inertia and casing friction on consistent, closed form equations for the free surface, pressure, and velocity fluctuations for overdamped and underdamped conditions. A consistent, but small, correction for kinetic energy is included as well. A characteristic velocity linearizes the turbulent casing shear stress so that an analytical solution for attenuated, phase shifted pressure fluctuations fits a single parameter (damping frequency) to transducer data from any depth in the casing. Underdamped slug tests of 0.3, 0.6, and 1 m amplitudes at five transducer depths in a 5.1 cm diameter PVC well 21 m deep in the Plymouth-Carver Aquifer yield a consistent hydraulic conductivity of 1.5 x 10-3 m/s. The Springer and Gelhar (1991) model underestimates the hydraulic conductivity for these tests by as much as 25% by improperly ascribing smooth turbulent casing friction to the aquifer. The match point normalization of Butler (1998) agrees with our fitted hydraulic conductivity, however, when friction is included in the damping frequency. Zurbuchen et al. (2002) use a numerical model to establish a similar sensitivity of hydraulic conductivity to nonlinear casing friction. [ABSTRACT FROM AUTHOR]

In a replicated field experiment, ryegrass, vetch and red clover were grown or the soil was kept bare over a 2-month period in summer to compare the effects of these treatments on slug damage to the following crop (Chinese cabbage) and on the efficacy of nematodes (Phasmarhabditis hermaphrodita) applied as biological control agents to the soil at planting time to protect this crop. Slug damage was significantly (c. two times) greater after red clover or vetch than after ryegrass. Damage on plots without cover crop was intermediate and not significantly different from either extreme. Slug damage was reduced by about one-third by the nematode treatment. The preceding cover crop did not influence nematode efficacy. Numbers of slugs on harvested plants (mainly Deroceras reticulatum and Deroceras panormitanum) were influenced by an interaction between cover crop and nematode treatment. On subplots without nematodes, more slugs were recorded with than without a preceding cover crop. No such differences were found on nematode-treated subplots. Soil samples were collected at intervals from 0-99 days after nematode treatment to monitor nematode survival and infectivity in bioassays with D. reticulatum. No significant effects of cover crops were detected in bioassays. Moreover, there were no significant effects of nematodes on slug survival. Their effects on slug food consumption were mostly insignificant and any effects were transient and not consistent. However, significantly more slug cadavers contained nematodes when slugs were exposed to nematode-treated soil. The implications of these results are discussed. [ABSTRACT FROM AUTHOR]

The behavioural response of the slug Deroceras panormitanum (Lessona and Pollonera) and the snail Oxyloma pfeifferi (Rossmässler) to novel molluscicides was investigated in choice and no-choice experiments. Low-light video-recording in combination with automated tracking and event recording was used to identify the repellent and irritant effects of (1) cinnamamide, (2) copper ammonium carbonate, (3) a mulch, (4) a horticultural ground-cover matting impregnated with a copper formulation and (5) urea/formaldehyde. In the no-choice experiments the products had a stronger irritant effect on the snails than on the slugs. All products tested except the mulch significantly reduced the locomotor activity of both the slugs and snails. The most effective product, cinnamamide, reduced snail locomotor activity by 94% and track length by 96%. The overall repellent effect of the treatments in the choice experiments was stronger in the slugs; where presence, locomotor activity and track length in the treated area were significantly reduced by all products. The avoidance of treated areas exceeded 95% with the mulch (for slugs) and with copper ammonium carbonate (for snails). [ABSTRACT FROM AUTHOR]