A survey was carried out to find non-parasitic nematodes associated with slugs and snails in order to elucidate the initial phase of endophoresis and necromeny in gastropods. 78 % of the specimens of the 12 terrestrial gastropod species surveyed carried nematodes. A total of 23 nematode species were detected alive and propagable in gastropod faeces, with 16 different species found in Arion rufus alone. Most were saprobiontic rhabditids, with species of Caenorhabditis, Oscheius and Panagrolaimus appearing with some regularity. The nematodes were accidentally ingested with food and survived the passage through the digestive tract, allowing them to be transported to suitable microhabitats such as decaying fruits or fungi. The intestines of snails and slugs taken from hibernation or aestivation were free of nematodes. Seven gastropod species were experimentally infected with eight rhabditid species, all of which were able to persist uninjured in the intestines of the gastropods for two to five days before being excreted with the faeces. A list of nematode species accidentally associated with gastropods is compiled from the literature for comparison. The role of gastropods in spreading nematodes and other small animals (a few observations on rotifers and mites are mentioned) deserves more attention.

The immature spermatozoa stored in the testis and female postvulval uterine sac (PUS), and mature spermatozoa from the uterus of the free-living marine nematode Daptonema sp. (Monhysterida: Monhysterina: Xyalidae) were studied. The spermatozoa have a nucleus without a nuclear envelope. The central cytoplasm of the immature spermatozoa from the testis and the distal part of the PUS is occupied by a mass of pale fibrous bodies (FB) surrounded by mitochondria and osmiophilic membranous organelles (MO). The spermatozoa in the proximal half of PUS have a wide peripheral layer of electron lucent filamentous cytoplasm. The uterus lumen contains an aggregation of mature spermatozoa of which the periphery is transformed into pseudopods. The FB replaced by a voluminous electron-lucent halo bounded by a continuous layer of MO, mitochondria and fibrous matter. The MO may be intact, but numerous MO are fused with the plasma membrane, having been transformed into transparent pouches, each one opening to the exterior via a pore. Ultrastructural data showed that the activation is regulated in the female when spermatozoa migrate toward the uterus and transform into amoeboid mature spermatozoa. In general, the spermatozoa of Daptonema sp. and some other Monhysterina closely resemble those of the taxa belonging to the order Rhabditida. However, the `rhabditid' pattern of spermatozoon structure and development is most likely the plesiomorphic state in Rhabditida and close sister groups.

A study was conducted to evaluate the effects of temperature on the infective efficacy of 3 isolates of Heterorhabditis bacteriophora (IH-C3, IH-C6, IH-C13) associated with green strains of Photorhabdus luminescens (infected larvae of Galleria mellonella L. turn green) in comparison with 3 isolates of H. bacteriophora (IH-ME2, IH-LU1, IH-CE1) associated with red strains of Photorhabdus luminescens (infected larvae turn red). The percentage of larval mortality was recorded after a 72-h exposure period to the infective juvenile nematodes (Ijs) at various temperatures between 10°C and 35°C, at intervals of 5°C. For all nematode strains the highest larval mortality was recorded at 25-30°C. The data showed that temperature had a significant influence on host mortality for all H. bacteriophora isolates tested. Strain IH-CE1 showed the highest larval mortality percentage for the range 20-35°C. There were no significant differences among red and green isolates at the same temperatures except for one case: at 20°C the red isolates were more virulent than green ones. Key words: entomopathogenic nematodes, pine forest, olive-grove, maize field, bioassay. CONFRONTO DI PATOGENICITA TRA CEPPI “ROSSI” E “VERDI” DI HETERORHABDITIS BACTERIOPHORA POINAR 1976 (RHABDITIDA: NEMATODA) IN RELAZIONE ALLA TEMPERATURA. E stata valutata la patogenicita di 3 isolati Italiani di Heterorhabditis bacteriophora (IH-C3, IH- C6, IH-C13), il cui batterio simbionte Photorhabdus luminescens fa diventare le larve test di colore verde, con 3 isolati di H. bacteriophora (IH-ME2, IH-LU1, IH-CE1) che colorano le larve infe- state di rosso. I dati sulla mortalita sono stati rilevati 72 ore dopo aver sottoposto larve di Galleria mellonella ad una sospensione acquosa di 1000 Ijs/ml. a 10-15-20-25-30-35 °C. Per tutti gli isolati il tasso di mortalita piu elevato si e verificato tra i 25 e i 30°C. IH-CE1 ha ucciso un maggior numero di larve di G. mellonella tra i 20 e i 35°C. Alle diverse temperature testate non si sono avute differenze significative tra gli “isolati rossi” e quelli “verdi”; soltanto a 20°C gli “isolati rossi” hanno mostrato una maggiore patogenicita nei confronti con gli ” isolati verdi”. Parole chiave: nematodi entomopatogeni, pineta, oliveto, campo di mais, test di patogenicita.

A baseline survey was conducted to determine the occurrence and distribution of soil nematodes associated with cotton in major growing areas in Kenya. Such baseline data on soil nematode abundance, diversity and ecosystem function in cotton ecosystems are valuable in providing a basis for comparison with organisms from transgenic cotton fields. Transgenic cotton plants expressing Cry1Ac and Cry2Ab proteins, from the soil bacterium Bacillus thuringiensis (Bt), provide effective control of lepidopteran pests. However, the potential effects of these proteins on soil nematofauna are unknown in Kenya. Soil samples were collected from nine locations of western (Odiado, Angorom and Ochundo locations), coast (Baharini, Mpeketoni and Witu locations) and central (Kajiji, Tebere and Nyangati locations) province. Nematodes were extracted and recovered from soil samples using the Whitehead and Hemming tray method and identified under a light microscope according to their morphological characters. They were classified according to their feeding habits. Twenty seven genera of plant parasites, bacteriovores, fungivores, predators and omnivores were identified. Bacterial, fungal feeding and parasitic nematodes were the most abundant trophic groups across all provinces. There were significant differences in the numbers of bacteriovores (P £ 0.01) and plant parasites (P £ 0.05) between the provinces but no difference was observed in the numbers of fungal feeding nematodes. There was a significant difference in genus richness within locations in western and coast provinces (P < 0.001). The combined maturity index (_MI) did not vary significantly within the locations. The Shannon index (H’) showed variations within locations in western (P < 0.001) and coast province (P £ 0.01). Soil texture, P and K were correlated with abundance of some nematode genera. The bacteria feeders, Acrobeles and Rhabditis showed positive correlations to K (r = 0.592, P < 0.05 and r = 0.128, P £ 0.05) and P (r = 0.406, P£ 0.05, and r = 0.252, P < 0.05) while Aphelenchus was positively correlated to P (r = 0.375, P £ 0.05). The plant parasitic genera Meloidogyne and Pratylenchus showed significant negative correlation to N (r = -0.513, P £ 0.05 and r = -0.226, P £ 0.05). It is clear from this baseline data that plant parasitic and free living nematodes are widespread in cotton fields and any potential effects of Bt cotton on these nematodes may affect the nematode community structure and their ecosystem functions. Key words: Cotton, soil nematodes, survey.

Entomopathogenic nematodes (Rhabditida: Steinernematidae and Heterorhabditidae) are generalist obligate pathogens present in the soil of most ecosystems. They have the potential to infect a broad host range, yet the potential for endemic entomopathogenic nematodes to regulate soil-dwelling insect populations has received limited attention. I investigated the population dynamics of endemic entomopathogenic nematodes to determine their ability to regulate annual bluegrass weevil (Listronotus maculicollis) (Coleoptera: Curculionidae) populations, a major pest of turfgrass in the northeastern United States. Weekly sampling of nematode and L. maculicollis populations was conducted in untreated fairway transects on three golf courses in New Jersey between April and October of 2006 and 2007. Steinernema carpocapsae Weiser and Heterorhabditis bacteriophora Poinar were found infecting all weevil stages from third instar to teneral adults. Both nematode species exhibited a distinct seasonality, appearing in high densities in the weeks immediately following high densities of first generation weevils in the soil. A positive temporal relationship was

White rice stem borer ( Scirpophaga innotata ) is a destructive insect pest which is difficult to control with various tactics. The possibility of the use of non-endemic natural enemies such as entomopathogenic nematodes (Rhabditida: Steinernema and Heterorhabditis) has been investigated in green house trials. Test of 12 isolates and species of Steinernema and Heterorhabditis originated from local and exotic sources revealed that H. indicus INA H4 was the most efficacious nematode by causing 74% larval and pupal mortality within rice stems. Reduction in plant damage due to nematode application could not be demonstrated as the experiment was limited to potted plants. Subsequent test using H. indicus INA H4 showed that increasing nematode concentration from 0.5 to 2.0x10^4 IJs/ml did not significantly affect insect mortality. The survival ability of H. indicus INA H4 infective juveniles on rice plant was less than 96 hours. Improvement of nematode application strategies including repeated spray, addition of antidesiccant, increasing spray volume and application at plant damage threshold or plant critical stage are therefore necessary to increase nematode effectiveness and simultaneously to reduce plant damage in field.

I. THE NEMATODE WORLD Of every five animals on the planet, four are nematodes (Platt 1994). The vast majority are free-living microbivores, but many species have adopted a parasitic lifestyle. Most plants and animals have at least one parasitic nematode species uniquely adapted to exploit the concentration of food and resources that the host species represents. The reasons for the success of the Nematoda as parasites probably include the presence of an environmentally protective cuticle, facultative diapause (like the dauer stage of Caenorhabditis elegans ), biochemical adaptations to existence in extreme conditions, and the use of a variety of reproductive strategies. Some parasitic nematodes are the subject of extensive research efforts, often aimed at understanding their lifestyle and ecology so as to control or manage them better. The choice of the free-living rhabditid C. elegans as a model for metazoan development has been fortunate for the study of other nematodes, particularly parasites. Although only distantly related to most parasitic species, C. elegans displays the morphological conservatism of the phylum and shares structures found to be important to parasitic species. It also has a characteristic nematode biochemistry and has proved to be sensitive to all the major nematicidal drugs. In this chapter, we first provide an overview of the diversity and importance of parasitic nematodes and subsequently describe three systems where research on C. elegans is having a significant impact on parasitology. Historically, the study of nematodes has fragmented into three major branches (plant nematology, animal parasitology, and free-living nematology) that have...

In this paper some aspects of the microfaunistic population of the arid biotopes of Western mediterranean countries are exposed. The desert milieu, the steppoidean lands and the dray moss habitats are specially treated. Special references concern the Iberian peninsula and North Africa. In the desertic ambients the soil life in Saharian lands is studied, and its population referred to Bacteria, Fungi, Algae and hydrophilic elements of microfauna: Thecamoebians, Ciliates, Rotifers, Tardigrada and Nematoda. Among these, specially notable are Rhabditis producta , Helichothylenchus africanus, Plectus granulosus and Acrobeloides butschlii . In the steppoidean milieu the littoral plains of Morocco and the Ebro basin in Spain principally are studied in the same way. Special reference to gypsum soils and salt water habitats are given. Among the Nematoda are typical Eudorylaimus carteri, Mesodorylaimus bastiani, Plectus cirratus, P. parietinus, Tylenchus (F.) filiformis, Rhabditis pellio and Acrobeloides emarginatus . The dry moss habitats of Central and SW counties of Iberian peninsula, including also the calcareous rocks. The microfauna is more rich and the dominant forms among the Nematoda are Eudorylaimus carteri, Plectus cirratus and Tylenchus (F.) filiformis , followed by Rhabdolaimus terrestris, Mesodorylaimus bastiani, Wilsonema auriculatum, Teratocephalus crassidens, Ditylenchus intermedius, Acrobeloides emarginatus and Cephalobus nanus . The desert and dry milieus are not uninhabited places; the microfaunistic population in arid environments is important and very significative.

The stoma has been studied in several genera of the Dorylaimina. An attempt has been made to homologize the different parts of the stoma throughout this group and with parts of the rhabditid stoma. Attention has been paid to the stomatal muscles of which an hitherto unrecorded set is described.