The chemical ecology of some British freshwater gastropod molluses: behavioural responses to short chain carboxylic acids and maltose

SUMMARY. 1. The behavioural responses of six species of British freshwater gastropods to chemical gradients of short chain carboxylic acids (C-2 to C-5, C-8) and maltose were investigated by means of diffusion olfactometers.
2. The species were ranked as follows on the basis of the number of significant behavioural responses to the test chemicals: Lymnaea peregra > Planorbis contortus > Physa fontinalis > Planorbis planorbis > Bithynia tentaculata > Planorbis vortex. These differences were not a result of differences in activity but reflect real differences in ehemoreception.
3. Propanoate (C-3) was a significant attractant or arrestant to five snail species, C-4, C-8 and maltose to four species and C-5 to three species. Acetate (C-2) was a significant attractant to L. peregra and P. fontinalis but it was the only acid to act as a repellent, to P. planorbis and B. tentaculata.
4. Lymnaea peregra continued to respond to repeated butanoate application. Response levels could be enhanced by increasing concentration (minimum thresholds 10^-4M to 10⁻⁵ M), pH (above 6) and food deprivation.
5. The ecological relevance of the results are discussed with particular reference to the distributional patterns of the chemicals and snails and the feeding niches of the latter.     

Toxic effects of cadmium and zinc on the transmission of Echinoparyphium recurvatum cercariae

The toxicity of cadmium, zinc and Cd/Zn mixtures to the transmission of Echinoparyphium recurvatum (Digenea: Echinostomatidae) cercariae into the snail second intermediate hosts was investigated at concentrations ranging from 100 microg l-1 to 10 000 microg l-1 in both soft and hard water. A differential response in the infectivity of metal-exposed cercariae into Lymnaea peregra and Physa fontinalis was demonstrated which was dependent on the snail species being infected. Exposure of L. peregra, P. fontinalis, and L. stagnalis to heavy metals caused a differing susceptibility to E. recurvatum cercariae depending on the snail species being exposed. The mechanism and effects of metal toxicity, together with the importance of the parasite/host strain on cercarial transmission are discussed.     

Macrophyte-gastropod associations: observations and experiments on macrophyte choice by gastropods

SUMMARY.

• 1 The abundance and microdistribution of thirteen gastropod and ten macrophyte species were monitored over 2 years in a 1 ha shallow eutrophic pond near Oxford, England. While areas of allochthonous leaf litter supported a depauperate and nondistinctive gastropod fauna, three different macrophyte habitats supported more diverse and distinctive assemblages of gastropods.
• 2 Most gastropod species were clearly more abundant (number m^-2pond bottom) on one macrophyte type than on other substrates. One exception, the limpet Acroloxus lacustris (Linn.) was abundantion both the water lily Nymphaea alba L. and on emergent macrophyles. Planorbis vortex (Linn.) was associated with graminoid emergent macropytes, especially Glyceria maxima (Hartm.) Holmberg, while Lymnaea peregra (Mull.) was associated with submersed macrophytes, perhaps more particularly with Elodea canadensis Michx.
• 3 The association of, 4. lacuxtris with N. alba and emergent macrophytes is perhaps explained by constraints of the morphology of the limpet requiring a relatively broad smooth substrate for attachment and locomotion.
• 4 The reason for the associations of P. vortex with G. maxima, and of L. peregra with E.canadensis are less obvious. Experiments giving each snail species a choice between the two macrophytes showed that P. vortex regularly exhibited a preference for G. maxima but failed to reveal substrate selection by L. peregra. Neither snail species affected the macrophyte choice of the other. The results suggested that L. peregra did not behave naturally in experiments.
• 5 The preference for G, maxima by P. vortex was not affected by prior conditioning of the plant by the snail, but was affected by the emergent nature of G. maxima and by the presence/absence of a natural periphyton assemblage and associated detritus.
• 6 The distribution of A. lacustris is probably determined by the physical structure of the substrate, while that of P. vortex is determined by the presence and quality of epiphytic periphyton-detritus. The observations and experiments with L. peregra reported here leave the reasons for its distribution in doubt.

     

Grazing by oligochaetes and snails on epiphytes

SUMMARY. 1. The isotope ³³P was used to assess the effect of grazitig by oligochaetes (mainly Stylaria lacttstris L.) and the snail, Lymnaea peregra (Muller), on epiphytes within an Equisetum fluviatile L. stand.
2. Two 1 m² polystyrene enclosures were set up within the emergent macrophyte zone of the lake. At the start of the experiment ³³P-solution was mixed with the water in both tanks. Algal and animal samples for ³³P- analysis were collected during the peak occurrence of epiphytes in June.
3. Phosphorus release rates from the animals through defaecation and excretion were measured in the laboratory. The grazing rate of oligochaetes was 2.2–4.1 mg P m⁻² (of bottom) d⁻¹ of which about two - thirds was released and recycled. The oligochaete density ranged from 13,400 to 20,900 m⁻². The snails (25 ind. m⁻²) grazed 1.2-1.5 mg P m⁻²d⁻¹of whieh about a quarter was released through defaecation and excretion.
4. Daily consumption by the oligochaetes and snails corresponded to 22–45% of the average phosphorus uptake by the epiphytes.     

Cadmium toxicity and snail-digenean interactions in a population of Lymnaea spp

The toxicity of cadmium to a population of Lymnaea peregra and L. stagnalis naturally infected with a range of digeneans and collected from a number of sites in the lower Thames Valley, UK was investigated. Lymnaeid snails were exposed to 100 microg l-1 cadmium and the effects on host survival and emergence of cercariae recorded. Overwintered L. peregra, but not L. stagnalis, showed significantly reduced survival compared to seasonally infected snails, i.e. snails which have acquired an infection during the spring or summer. A significant increase in survival with increasing snail size was demonstrated for L. stagnalis and for seasonally infected L. peregra only. Only L. stagnalis infected with Diplostomum spathaceum and L. peregra infected individually with D. spathaceum, Sanguinicola inermis, Echinoparyphium recurvatum and Notocotylus attenuatus demonstrated a significantly reduced survival compared to laboratory-bred controls. The exposure of L. stagnalis to cadmium resulted in a significant reduction in the emergence of D. spathaceum over a 5-day period but cadmium-exposed L. peregra showed no difference in the emergence of E. recurvatum cercariae over a 3-day exposure period. The mechanisms and importance of metal toxicity to snail-digenean interactions are discussed.     

Grazing interactions between pulmonate snails and epiphytic algae and bacteria

SUMMARY. 1. The effects of grazing by Lymnaca peregra and Planorbis planorbis on Ceratophyllum demersum epiphyton were investigated under simulated natural conditions.
2. Grazing resulted in significant reductions in algal cell densities, number of algal taxa and in diversity. Grazing did not influence equi-tabilily values.
3. The use of Ivlev's Electivity index demonstrated positive and negative selection by feeding snails for large, pedunculate, and small, adnate algae, respectively.
4. Inoculation of artificial surfaces revealed that 61.1% and 62.5% of the algal taxa presenl in the diet of L. peregra and P . planorbis , respectively (mainly the smaller species), were able to survive passage through the gut, resettle and grow.
5. The results are discussed with particular reference to the survival strategies available to the epiphytes, and the possible mutual benefits which algae and snails may derive from coexistence.     

Influence of cadmium exposure on the incidence of first intermediate host encystment by Echinoparyphium recurvatum cercariae in Lymnaea peregra

The effect of cadmium exposure of the snail first intermediate host Lymnaea peregra on the incidence of encystment of Echinoparyphium recurvatum (Digenea: Echinostomatidae) cercariae without emergence from the snail was investigated. Exposure to 100 microg l(-1) Cd for 72 h caused a significant increase in the incidence of first host encystment when compared to controls. In addition, autometallographic staining of E. recurvatum daughter rediae and developing cercariae showed that there was metal accumulation within their body tissues. The significance of these findings to parasite transmission in metal-polluted environments is discussed.     

Buchbesprechungen / Book Reviews

Book reviewed in this article:
Sachs, L. , Angewandte Statistik (Anwendung statistischer Methoden).
Progress in Botany (Fortschritt der Botanik). Morphology—Physiology—Genetics—Taxonomy—Geobotany. Herausgeber: K. E sser , K. K ubitzki , M. R unge , E. S chnepf , H. Z iegler .
Cummins, G. B., and Yasuyuki Hiratsuka , Illustrated Genera of Rust Fungi.
Pirson, A., and M. H. Zimmermann (Eds.) , Encyclopedia of Plant Physiology, New Series, Vol 12 D. O. L. L ange , P. S. N obel , C. B. O smond , H. Z ieg - ler (Eds.): Physiological Plant Ecology IV.
Mass, J. L. (ed) , Compendium of Strawberry Diseases.     

Coprophagy: a supplementary food source for two freshwater gastropods?

1. The freshwater pulmonate snail Radix peregra voluntarily and regularly fed on its faeces, whereas Bithynia tentaculata (Prosobranchia) did not.
2. With high-quality faeces as food (faeces with C : N-values below ten) Radix could grow and survived for 11 weeks. Growth was 24–30% of that achieved with control food (lettuce, Chlamydomonas and Tetramin), and body mass was close to the expected value.
3. As with real food, the percentage organic content of faeces was reduced during gut passage, with the exception of very low-quality faeces.
4. Faeces contained living cells of green algae ( Chlamydomonas reinhardii ) and diatoms ( Achnanthes lanceolata, Eunotia pectinalis ), which survived the gut passage of R. peregra and B. tentaculata . Faecal material was also rich in bacteria, with up to 150 × 10⁶ cells mg^–1 dry mass. Bacteria increased in abundance in faeces which had been evacuated for 7 days or more.
5. A further degradation of partly digested food in the faeces was indicated by the activity of the extracellular digestive enzymes cellobiase and chitobiase. These enzymes hydrolysed material with an activity of 0.2–14.5 pkat mg^–1 faecal dry mass in 1–12-day-old faeces. In faeces of Bithynia fed control food or incubated sycamore leaves, chitobiase activity was correlated with bacterial abundance.
6. Coprophagy is considered to be a suitable strategy for further degradation and utilization of refractory material for which one gut passage is too short and/or too inefficient.     

Prior flea beetle herbivory affects oviposition preference and larval performance of a potato beetle on their shared host plant

Abstract 1. The herbaceous plant Solanum carolinense (L.) (Solanaceae) is host to a number of specialist insects, including the leaf-feeding beetles Epitrix fuscula (Crotch) and Leptinotarsa juncta (Germar) (Coleoptera: Chrysomelidae). Potted individuals of S. carolinense were subjected to one of two treatments: exposure to herbivory by E. fuscula or exclusion of all herbivores. The effects of E. fuscula herbivory on larval performance and oviposition preference of L. juncta were investigated.
2. Although the masses of the L. juncta pupae did not differ between the two treatments, larvae feeding on damaged plants developed more slowly than those feeding on undamaged plants.
3. In both paired leaf choice trials and whole plant choice trials, larvae of L. juncta showed no preference for undamaged versus damaged hosts.
4. In a field transplant experiment, adult L. juncta females showed slight feeding preferences and strong oviposition preferences for undamaged plants versus plants that had been fed on by E. fuscula .
5. The results are discussed with reference to their implications for plant-mediated competition among herbivores and constraints on the evolution of plant resistance.     

Besprechungen

Book reviews in this article:
Angewandte Entomologie . Herausgegeben von R. F ritzsche , H. G eiler und U. S edlag unter Mitarbeit von L. B ritz , H. G. H erbst , J. O. H üsing , E. K arl , W. L ehmann , G. M asurat , H.-J. M üller , P. M üller , J. N itschmann , H.-W. N olte , G. P roeseler , H. B. S chmidt und W. T annert .
Kelman, A. et al. (Herausg.) , „Sourcebook of Laboratory Exercises in Plant Pathology.”
Proceedings of an international symposium on physiological and biochemical aspects of host-pathogen interactions . (Herausgegeben von A. F uchs und O. M. van A ndel )
Esau, K. , Viruses in plant hosts.
Oberzill, W. , Mikrobiologisdie Analytik — Grundlagen der quantitativen Erfassung von Umwelteinwirkungen auf Mikroorganismen.     

Buchbesprechungen / Book Reviews

Book reviewed in this articles:
Müller, E., und W. Loeffler , Mykologie.
Ayres, P. G. , Effects of disease on the physiology of the growing plant.
Staples, R. C, and G. H. Toenniessen (Eds.) , Plant Disease Control: Resistance and Susceptibility.
Schenck, N. C. (Ed.) , Methods and Principles of Mycorrhiza Research.
Dekker, J., and S. G. Georgopoulos (Eds.) , Fungicide resistance in crop pro-tection.
Perkow, W. , Wirksubstanzen der Pflanzen- und Schadlingsbekampfungsmittel.     

Reviews

Book reviewed in this article:
The Electron Microscope. By M. E. H aine
Chemical Control of Insects. 2nd ed. By T. F. W est and J. E liot H ardy.
Principles of Animal Taxonomy. By G. G. S impson.
Encyclopaedia of Plant Physiology. (The late W. R uhland ed.)
Mechanisms in Biological Competition. (Symposia of the Society for Experimental Biology. XV.) Edited by F. L. M ilthorpe.     

REVIEWS

Book reviewed in this article:
A Course in Biology . By J. J. B aker and G. E. A llen .
Papers on Plant Systematics . By R. O rnduff .
Die Entstehung der Arten und hoheren Kategorien . By H. L amprecht .
Flora of Iraq , Vol. 9. Gramineae . By N. L. B or . (Ed. by C. C. T ownsend and E van G uest , with the collaboration of A li A l -R awi ).
Wild Elowers of North Carolina . By W illiam S. J ustice and C. R itchie B ell .
The Lichen Genera Cetrelia and Platismatia ( Parmeliaceae ). By W. L. C ulberson and C. F. C ulberson .
Essays on Form in Plants . By C. W. W ardlaw .
Crop Responses to Water at Different Stages of Growth . By P. J. S alter and J. E. G oode .
Protons, Electrons, Phosphorylation and Active Transport . By R. N. R obertson .
Encyclopedia of Plant Physiology, XVIII, Sexuality: Reproduction; Alternation of Generations . General editor, W. R uhland ; sub-editor for this volume, H. F. L inskens .
Annual Review of Plant Physiology , Vol. 19. 1968. By L. M achlis (Ed.).
Biophysical Technique as Applied to Cell Biology . By J. C hayen and E. E. D enby .
The Measurement of Environmental Factors in Terrestrial Ecology . British Ecological Society Symposium No. 8. Ed. by R. M. W adsworth et al .
Guide to the Check Sheet for IBP Areas . IBP Handbook No. 4. By G. E. P eterken .     

Book Reviews

Wilkinson, R. E. (ed.) Plant-Environment Interactions, Second Edition.
Stacey, G.; Keen, N. T. (eds) : Plant-Microbe Interactions.
Shurtle, M. C.; C. W. Averre Ill : Diagnosing Plant Diseases Caused by Nematodes.
Tjamos, E. C., R. C. Rowe, J. B. Heale, D. R. Fravel (eds) : Advances in Verticillium: Research and Disease Management.
Frederiksen, R. A.; G. N. Odvody (eds) : Compedium of Sorghum Diseases.
Podila, G. K., D. D. Douds Jr. (eds) : Current Advances in Mycorrhizae Research.
Kronstad, J. W. (ed.) : Fungal Pathology.
Agrawal, A. A., S. Tuzun, E. Bent (eds) : Induced Plant Defenses against Pathogens and Herbivores. Biochemistry, Ecology, and Agriculture.
Bartels, G.; Backhaus, G. F. (Hrg.) : Die Pr̈ng von Panzen auf ihre Widerstandsfhigkeit gegen Schadorganismen in der Biologischen Bundesanstalt. Teil 2 Resistenzpr̈ng von Kulturpanzen im Acker- und Gartenbau gegen Pilze, Bakterien und Viren-Testing of crop cultivars for resistance to noxious organisms at the Federal Biological Research Centre. Part 2. Testing of resistance of field and horticultural crops to fungi, bacteria and viruses. Mitt. Biol. Bundesanstalt för Land- und Forstwirtschaft, Berlin-Dahlem, Heft 373.
Bacon, Ch. W., L. F. White Jr. (eds) : Microbial Endophytes.
Siddiqi, M. R. : Tylenchida. Parasites of Plants and Insects.
Khetan, S. K. : Microbial Pest Control.
Upadhyay, R. K., K. G. Mukerji, B. P. Chamola (eds) : Biocontrol Potential and its Exploitation in Sustainable Agriculture.     

Distribution and hosts of Callidiellum rufipenne (Coleoptera: Cerambycidae), an asian cedar borer established in the eastern United States

The distribution and hosts of the exotic cedar-boring beetle, Callidiellum rufipenne (Motschulsky) (Coleoptera: Cerambycidae), were determined in five northeastern U.S. states by capturing adults on cedar trap logs and by rearing adults from various conifers. This beetle was detected in the coastal states of Massachusetts, Rhode Island, Connecticut, New York, and New Jersey. In these states, adults emerged from the live or dead wood of four genera and eight species of Cupressaceae; species of Pinaceae were not hosts. Through its entire range, C. rufipenne is reported to infest at least 14 species of Cupressaceae, four species of Pinaceae, and one species of Taxaceae; but, records of Pinaceae and possibly Taxaceae are suspect. Based on the number of adults that emerged from coniferous poles in a five-way choice test in the field, the infestation level was significantly greater in Chamaecyparis thyoides (L.) Britton, Sterns, and Poggenburg and Juniperus virginiana L. than in Pinus rigida Miller, Pinus strobus L., and Tsuga canadensis (L.) Carribre (last three species uninfested). In a second test of host preference in the wild, beetles infested four cupressaceous species, but not Abies balsamea (L.) Miller, Picea rubens Sargent, Pinus rigida, P. strobus, and Ts. canadensis in the Pinaceae. Infestation level was highest in Ch. thyoides, followed in decreasing order by Juniperus communis L., Thuja occidentalis L., and J. virginiana. In a comparison of live and dead J. virginiana, beetles developed to adults only in dead trees (36 beetles per tree). When trunk sections of Th. occidentalis with and without bark were offered to females in cages, beetles of the next generation emerged exclusively from wood with bark. In the Northeast, only species of Cupressaceae apparently are suitable hosts for C. rufipenne. Infestation of these species may be prevented or reduced by proper care of live plants and by debarking trees after harvesting.     

Life-cycle of Euparyphium albuferensis n. sp. (Trematoda: Echinostomatidae) from rats in Spain

The morphology of the different life-history stages and life-cycle of Euparyphium albuferensis are described and drawn. The freshwater snail Gyraulus chinensis (Gastropoda: Planorbidae) serves as the natural and experimental first intermediate host. This and other freshwater snails, such as Lymnaea truncatula, L. peregra, L. palustris and Physa acuta, serve as second intermediate hosts. Adult worms, possessing 45 collar spines, were obtained naturally from Rattus norvegicus and R. rattus, and experimentally from albino rats, mice and golden hamsters. Chickens, ducks and pigeons were not suitable experimental definitive hosts. E. albuferensis differs from the most closely related species, E. murinum Tubangui, 1931, in its larger body, suckers and oesophageal measurements, in the distribution of vitelline follicles and in the morphology of the collar spines.     

REVIEWS

Book reviewed in this article:
A Dictionary of the Flowering Plants and Ferns . By the late J. C. W illis . Seventh edition, revised by H. K. A iry S haw .
The Principles of Pollination Ecology . By K. F aegri and L. van D er P ijl .
Studies in Biology, No. 5, Plant Taxonomy . By V. H. H eywood .
Deadly Harvest . By J ohn M. K ingsbury .
Plant Physiology . By H enrik G. L undegardh . Translated by F. M. I rvine , Translation edited by W. O. J ames .
The Biology of Lichens . By M ason E. H ale J r . In: Contemporary Biology Series, General editors E. J. W. B arrington and A. J. W illis .
Plant Biology Today . Second edition. Ed. by W. A. J ensen and L. G. K avaljian .
Organisation in Plants . Second edition. By B. M. B aron .
Fortschritte der Botanik , Band 28. Ed. by E. B ünning , H. E llenberg , K. E sser , H. M erxmuller and P. S itte .
Taxonomy of Flowering Plants . Second edition. By C. L. P orter .
The Study of Biology . By J. J. W. B aker and G. E. A llen .
Experiments in the Study of Biology . By J. J. W. B aker , G. E. A llen , E. G age and S. K. W ebster .
Grundriss der Phytopathologie iind des Pflanzenschutzes . By H ans -A lfred K irchner .
Bibliography of Seeds . Compiled and edited by L. V. B arton .
Pollen Grains of Western Himalaxan Plants . By P. K. K. N air .
Families of Flowering Plants in Ethiopia . By W. C. B urger .     

REVIEWS

Book reviewed in this article:
Excursion Flora of the British Isles , 2nd edn. By A. R. C lapham , T. G. T utin and E. F. W arburg .
Critical Supplement to the Atlas of the British Flora . Ed. by F. H. P erring assisted by P. D. S ell .
Drawings of British Plants . Part XXIV. Labiatae . By S tella R oss -C raig .
Britain's Green Mantle , 2nd edn. By the late A. G. T ansley . Revised by M. C. F. P roctor .
The Flora of Berkshire . By H. J. M. B owen .
Flora of Turkey and the East Aegean Islands . By P. H. D avis , assisted by J. C ullen and M. J. E. C oode .
Plants and Man on the Seychelles Coast . By J. D. S auer .
Key to the Families of Flowering Plants of the World . Revised and enlarged by J. H utchinson .
The Diversity of Green Flants . By P. R. B ell and C. L. F. W oodcock .
IBP Handbook No . 5: Handbook to the Conservation Section of the International Biological Programme . By E. M. N icholson .
Plants, Man and Life , 2nd edn. By E dgar A nderson .
Production and Mineral Cycling in Terrestrial Vegetation . By L. E. R odin and N. I. B azilevich . Translation by Scripta Technica Ltd (Ed. by G. E. F ogg ).
'Torrey Canyon' Pollution and Marine Life . A Report by the Plymouth Laboratory of the Marine Biological Association of the United Kingdom. Ed. by J. E. S mith .
Geobotanische Untersuchungen auf der Feddersen Wier de . By U. K örber -G rohne .
Cell Walls and Membranes . By H. J. R ogers and H. R. P erkins .
Wachstums regulatoren bei Pflanzen . Ed. by E. L ibbert and B. S teyer .
The Ecology of Soil Bacteria ( An International Symposium ). Ed. by T. R. G. G ray and D. P arkinson .
Genetics of Fungi . By K arl E sser and R udolf K uenen . Translated by E rich S teiner .
Plant Pathologist's Pocketbook . Compiled by The Commonwealth Mycological Institute.     

Reviews

Comparative Animal Physiology. By C. L add P rosser et al.
Organisme et Sexualité. By M. C aullery .
Embryos and Ancestors. By G. R. de B eer .
The Association of Ants with Aphids and Coccids. By G. E. J. N ixon .
Soil and Fresh-Water Nematodes. By T. G oodey
Die Überträger pflanzlicher Viruskrankheiten (The vectors of plant viruses). By K urt H einze .
Leaf Curl Disease of Cotton. By S. A. J. T arr .
Introduction to Mycology. By J. A. M ac D onald .
Pesticide Handbook 1951. Edited by D. E. H. F rear .
Pflanzliche Infektionslehre. By E rnst G äumann .
A Dictionary of Biology. By M. A bercrombie , C. J. H ickman and M. L. J ohnson .
Soviet Genetics. By A. G. M orton .
Gall Midges of Economic Importance. Vol. v. Gall Midges of Trees. By H. F. B arnes .
Four Thousand Million Mouths. Scientific Humanism and the Shadow of World Hunger. Edited by F. L e G ros C lark and N. W. P irie .