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Volume 4, Part 1 (1996)

  • N.N. Zakharenkova. Howardula phyllotretae (Tylenchida: Allantonematidae) - parasite of Phyllotreta flea beetles (Coleoptera: Chrysomelidae), 1-6.
  • P.A.A. Loof. Dichotomous and polytomous identification keys for females of the genera Prodorylaimus Andrassy, 1959 and Laimydorus Siddiqi, 1969 (Nematoda: Dorylaimoidea), 7-28.
  • S.A. Subbotin, H.J. Rumpenhorst and D. Sturhan. Morphological and electrophoretic studies on populations of the Heterodera avenae complex from the former USSR, 29-38.
  • T.G. Miroshnik. The potato cyst nematode, Globodera rostochiensis, in the Ukraine, 39-42.
  • A.V. Tchesunov, V.V. Malakhov and V.V. Yushin. Comparative morphology and evolution of the cuticle in marine nematodes, 43-50.
  • A. Coomans. Phylogeny of the Longidoridae, 51-60.
  • S. Lorenzen. The metamorphosis of traditional into advanced phylogenetic systematics and its impact on nematode systematics, 61-70.
  • G.W. Yeates. Nematode ecology, 71-76.
  • Abstracts of papers presented at the First English Language International Symposium of the Russian Society of Nematologists (St. Petersburg, 23rd-30th September 1995), 77-104.
  • Book Review, 105.

Zakharenkova, N.N.

Howardula phyllotretae (Tylenchida: Allantonematidae) - parasite of Phyllotreta flea beetles (Coleoptera: Chrysomelidae)

A description of the free-living stages of entomogenous nernatode H. phyllotretae Oldham, 1933 is given for the first time. Data are presented on the prevalence and intensity of flea beetle infestation with these nematodes. Parasite induced changes in host reproductive system are described. An identification key for Howardula species is presented.

Key words: Tylenchida, Allantonematidae, Howardula phyllotretae, morphology, host-parasite relationships, key for Howardula.

Loof, P.A.A.

Dichotomous and polytomous identification keys for females of the genera Prodorylaimus Andrassy, 1959 and Laimydorus Siddiqi, 1969
(Nematoda: Dorylaimoidea)

Dichotomous and polytomous identification keys are given for females of species in the genera ProdoryIaimus and Laimydorus. It is necessasy to give combined keys for these two genera, because female specimens do not show any characters to indicate to which genus they belong. The genera Prodoiylaimium Andrassy, 1969 and Apodorylaimus Andrassy, 1988 are considered identical with Prodorylaimus, and, the genus Calodorylaimus Andrassy, 1969 identical with Laimydorus. Because Idiodorylaimus Andrassy, 1969 is very similar to Laimydorus, and because occasionally the distinguishing character (transverse cuticular striation) is difficult to observe, the species of Idiodorylaimus are included except one which possesses longitudinal cuticular ridges. As the morphology of females of the genus Afrodorylaimus Andrassy, 1964 does not differ from that of Laimydorus and
Prodorylaimus, Afrodorylaimus is also included.

Key words: identification, Laimydorus, Prodorylaimus, Apodorylaimus, Calodorylaimus, Prodorylaimium, Idiodorylaimus, Afrodorylaimus.

Subbotin, S.A., Rumpenhorst, H.J. and Sturhan, D.

Morphological and electrophoretic studies on populations of the Heterodera avenae complex from the former USSR

Isoelectric focusing of protein extracts of ten Heterodera 'avenae' populations from Russia, Ukraine and Tadzhikistan revealed a uniform protein pattern for all populations, except for one population from Putilovo, Leningrad region. A comparison with populations of H. avenae, H. mani and an obviously undescribed species of the H. avenae group from Germany showed that the population group from the former USSR is distinct from H. avenae and the other populations included in the study. Only the Putilovo population showed a protein pattern similar to the populations of the undescribed species. Morphological and morphometrical studies on the populations from the former USSR supported the results of the electrophoretic studies and the distinction of all populations from the H. avenae populations from Germany. The population from Tadzhikistan closely agrees with the orinnal description of H. filipjevi and all populations from the former USSR are considered as representatives of this species, except the Putilovo population which proved to represent another species within the H. avenae (s. str.) complex.

Key words: Heterodera avenae, H. filipjevi, electrophoresis, morphology, measurements, distribution, Russia, Ukraine, Tadzhikistan, Germany.

Miroshnik, T.G.

The potato cyst nematode, Globodera rostochiensis, in the Ukraine

It is estimated that G. rostochiensis, first recorded in the Ukraine in the early 1960s, has spread and now occurs in an area of 6000 hectares in 12 of the 14 regions in which potato production is a major arable enterprise. Chemical control of the nematode has proved to be ineffective and several regions with the largest nematode populations. Several potato cultivars have been bred in the Ukraine which are resistant and/or tolerant to G. rostochiensis and are effective at reducing the crop damage caused by the nematode.

Key words: control, distribution, Globodera rostochiensis, pathotype, resistance, tolerance.

Tchesunov, A.V., Malakhov, V.V. and Yushin, V.V.

Comparative morphology and evolution of the cuticle in marine nematodes

In embryos of some species of marine nematodes the somatic cuticle is formed with the assistance of short microvilli which disappear in subsequent developmental stages. The most primitive cuticle type in free-living species is a simple four-layered construction where mesocuticle is underdeveloped and may be poorly demarcated from the endocuticle. This cuticle type is broadly distributed among different marine nematode families and may be a transient stage in the ontogenesis of a complex cuticle. With progressive evolutionary development the cuticle becomes more complex as a result of additional stratification of the exo- and mesocuticles. Structurally the most complex cuticle, with stratified mesocuticle, is observed in large and active species. Other evolutionary trends appear to be correlated with particular specializations where the exocuticular zone predominates (e.g. Xennella, Halalaimus, certain Chromadoridae), secondary simplification (some Ceramonematidae - Pselionema), or development of secretory deposits (Desmoscolecidae). A few marine nematodes, because of their immobility, retain the embryonal cuticule-type through to, and including, the adult stage.

Key words: cuticle, marine nematodes, ultrastructure, comparative morphology, evolutionary morphology, transformation rows.

Coomans, A.

Phylogeny of the Longidoridae

The longidorid ancestor is reconstructed on the basis of primitive characters encountered in extant species of the family. The present distribution and morphology of the various genera are related to the geological history of the continents to trace the area of origin as well as the evolution within the family. The cladogram of the Longidoridae is amended and two possible classifications are proposed on the basis of the cladogram.

Key words: distribution, evolution, geological history, Gondwanaland, Longidoroides, Longidorus, Oceania, Paralongidorus, Paraxiphidorus, Xiphidorus, Xiphinema.

Lorenzen, S.

The metamorphosis of traditional into advanced phylogenetic systematics and its impact on nematode systematics

Phylogenetic systematics as proposed by Hennig has become very successlul. However, since its beginning, it has suffered from a fundamental mistake which appears inconsequential at first glance: the relative concepts of synapomorphy and symplesiomorphy were employed as if they were absolute. Closer inspection reveals the full impact of this mistake which has resulted in the exclusion of "symplesiomorphies", once recognized as such, from further analysis, and to transforming phylogenetic systematics into a form of nonphylogenetic systematics named cladistics which is not based in any way on the theory of evolution. By re-establishing the relativity of the concepts analysed, advanced phylogenetic systematics is achieved in which, by employing the so-called loss tracing method and knowledge ultimately inferred from the theory of evolution, traditional "symplesiomorphies", become exploitable for recognizing holophyletic species sets. Therefore, advanced phylogenetic systematics is superior to traditional phylogenetic systematics and cladistics. A nematological example is provided which demonstrates the new approach.

Key words: phylogenetic systematics, cladistics, parsimony, outgroup analysis, loss tracing method, theory of evolution, nematodes, Enoplida.

Yeates, G.W.

Nematode ecology

Plant and soil nematodes belong to the animal kingdom and thus the continued existence of each species requires that individuals obtain sufficient food to meet the requirements of the basic energy budget (consumption = respiration + wastes + body growth + reproduction). To fulfil these requirements nematodes must interact with other organisms in, and other components of; their environment. These interactions can be included under the following headings: food; temperature and moisture regimes; physical substrate; biological competition; developmental stage; assemblage (reflecting the total environment); soil or substrate processes. Although novel techniques enable new information to be obtained, it requires a problem to be defined to focus scientific enquiry. Currently, it appears that the dominant, unifying problem to be addressed in nernatode ecology is that of the duration of nematode activity as temperature and moisture regimes fluctuate in real substrates. Integrating such knowledge into conceptual or mathematical models would help to provide an understanding of the migration of plant-pathogenic nematode species to roots, the dispersal and survival of entomophilic nematodes, the relation between activity and biodiversity, the importance of micro-sites, and the proportion of time microbial-feeding nematodes actively contribute to soil processes.

Key words: nematode, development, ecology, soil, temperature, moisture, activity.