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1

A comparative study of the life strategies of two bacterial-feeding nematodes under laboratory conditions. 3, Influence on the initial nematode density on the interactions of Arobeloides nanus (de Man 1880) Anderson and Dolichorhabditis dolichura (Schnei

100%

Ilieva-Makulec K.

Polish Journal of Ecology

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2001

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tom Vol. 49, nr 2

137-144

EN

Population development and interactions between two bacterial-feeding nematodes Acrobeloides nanus and Dolichorhabditis dolichura were studied in mixed cultures at different initial density of nematodes. Population dynamics of the two studied species differed significantly in both competition experiments, with the initial numerical advantage of A. nanus as well as with the initial numerical advantage of D. dolichura. In all experimental variants population peak of D. dolichura occured always earlier than that of A. nanus. Population dynamics of A. nanus and D. dolichura depended significantly on the initial density of the second species in the mixed cultures. The higher initial density of D. dolichura the less abundant populations of A. nanus were noticed. However, no consistent trend in the influence of the A. nanus initial density on the abundance of D. dolichura was found. Numerical advantage of D. dolichura never led to the extinction of A. nanus and in the opposite, numerical prevalence of A. nanus in two cases resulted in a complete elimination of D. dolichura. Population dynamics of A. nanus and D. dolichura in mixed cultures showed a distinct difference in the way of food utilisation by these two species. As food resources become scarce with time, D. dolichura density decreased but A. nanus density started to increase. It appears therefore that, under the present laboratory conditions, A. nanus was the better competitor. That species maintained a positive growth rate even at low food concentrations at which its competitor could no longer sustained.

2

A comparative study of the life strategies of two bacterial-feeding nematodes under laboratory conditions. 1, Influence of culture conditions on selected life-history parameters of Acrobeloides nanus (de Man 1880) Anderson 1968 and Dolichorhabditis dolic

88%

Ilieva-Makulec K.

Polish Journal of Ecology

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2001

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tom Vol. 49, nr 1

29-43

EN

Selected life-history parameters like age of maturity, fecundity, egg development time, pattern of growth and reproduction, longevity and intrinsic rate of natural increase (r) were compared for two bacterial-feeding nematode species in xenic (with a several bacterial species as food) and monoxenic (with a bacteria Sporosarcina sp. as a food organism) agar cultures at 20 stopni C. There were pronounced differences in the life-history patterns of the two species in both types of culture conditions. D. dilichura showed a higher growth and development rate than A. nanus. D. dolichura had a shorter pre-reproductive period, a shorter reproductive period but more intensive pattern of reproduction, a shorter total life span and a considerably greater r than A. nanus. The differences in life-history traits of the two nematode species were discussed with reference to their adaptive significance for habitat properties. While D. dolichura represents short-lived habitats with temporarily high food supply, A. nanus can be found in habitats of various food abundance.

3

Plants with known antagonistic properties against pests: how they influence non-target free-living soil fauna?

44%

Ilieva-Makulec K. , Bielecki M. , Makulec G.

Studia Ecologiae et Bioethicae

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2017

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tom 15

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nr 4

41-53

PL

Praca dotyczy badań nad wpływem trzech gatunków roślin na wybrane wolnożyjące gatunki fauny glebowej. Zbadano bezpośredni wpływ wyciągu wodnego z liści konopi siewnych i miazgi czosnku na przeżywalność nicieni, wazonkowców i dżdżownic oraz w przypadku nicieni na płodność, dynamikę produkcji jaj i skuteczność wylęgania się jaj. W eksperymentach mikro- i mezokosmosowych natomiast oceniano pośrednie oddziaływanie ściółki z liści konopi oraz uprawy rącznika pospolitego na liczebność nicieni. Wyniki biotestów potwierdziły antagonistyczne działanie ekstraktów wybranych roślin. Najbardziej wrażliwe na substancje czynne wyciągu z liści konopi okazały się bakteriożerne nicienie Acrobeloides nanus, mniej wrażliwe wazonkowce Enchytraeus sp., a najbardziej odporne dżdżownice Dendrobaena sp. W przypadku nicieni i wazonkowców stwierdzono zależność toksycznego działania od stężenia wyciągu oraz czasu ekspozycji. Inkubacja samic A. nanus w wyciągach o różnym stężeniu wpływała na tempo składania jaj, długość okresu reprodukcji, skuteczność wylęgania się osobników młodocianych, natomiast nie miała wpływu na ich całkowitą płodność. Obecność ściółki z konopi w glebie jak i uprawa rącznika pospolitego wpływały pozytywnie na liczebność nicieni. Nasze wyniki pokazały, że pośredni efekt badanych roślin (zarówno w postaci ściółki, jak i poprzez system korzeniowy) różnił się od bezpośredniego działania zarówno intensywnością jak i kierunkiem wywołanych zmian.

EN

The aim of the study was to investigate the effect of three plant species with known antagonistic properties against pests on selected free-living species of soil fauna. The direct effects of aqueous extracts (from hemp leaves and garlic pulp) on the survival of representatives of nematodes, potworms and earthworms were studied. In the case of nematodes, the effects of hemp extracts on the egg production, total fertility and juvenile hatching efficiency were also assessed. Moreover the indirect plant impact (in the form of hemp litter added to the soil or through the root system during planting of castor bean) on soil nematodes was studied. The results of the bioassays confirmed the antagonistic effect of the plant extracts. The most sensitive to the hemp extract toxicity were nematodes, less potworms and at least earthworms. The toxicity of the hemp extract showed a clear dependence on its concentration. The garlic extract showed less toxicity to nematodes than the hemp extract did. The incubation of nematode females in the hemp extracts of different concentrations affected the rate of egg laying, the length of reproduction period and the hatching efficiency but did not affect their overall fertility. In soil, both the hemp litter and the castor plants had a positive indirect effect on the numbers of nematodes at least during the experiment.