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1.
To understand the life cycle of an organism, it is important to understand the physiological processes that govern growth and reproduction. In this paper, we re-analyse a life-cycle data set for the earthworm Eisenia veneta, using a process-based model. The data set comprises measurements of body size and cocoon production over 200 days, at two temperatures (15-25 °C) and two densities (five and 10 worms per container, but with the same worm:soil weight ratio). The model consists of a set of simple equations, derived from Dynamic Energy Budget (DEB) theory. The dynamics of growth and reproduction are simultaneously described by the model, using very few parameters (five parameters for four curves). This supports the use of this model for efficient analysis of earthworm life-cycle data, and to interpret the effects of stressors. However, there was considerable inter-individual variation in the response, hampering the interpretation of the temperature and density effects. A temperature increase corresponded to an increase in the rate constants for growth and reproduction (with the same factor), without affecting the other parameters, as expected from DEB theory. Changing the earthworm density hardly affected the growth curves, but had an unexpected effect on reproduction: at higher densities, the worms start to produce cocoons at a larger body size and the maximum reproduction rate was lower. This study confirms the use of DEB as a reference model for earthworms, and using this model, we can recognise that temperature has a predictable effect on the life cycle of E. veneta. Furthermore, this analysis reveals that the effects of density are less clear and may involve a change in energy allocation that requires further study.  相似文献   

2.
This study aimed to evaluate short-term earthworm-induced changes in the availability of metals applied to soil directly (metal-spiked) or via an organic matrix (sludge-amended). A laboratory experiment was performed using destructive sampling of microcosms filled with agricultural soil. A concentration gradient of industrial sludge contaminated predominantly with Cr, Cu, Ni, and Zn, and a soil freshly spiked with the same metal concentrations were applied on top of the soil columns. Individuals of Dendrobaena veneta (mimicking a realistic density of 500 earthworms per m2) were introduced in half of the replicates of each treatment. Total and 0.01 M CaCl2 extractable metal concentrations were measured in soil after 0, 3, 6 and 12 weeks and metal concentrations in earthworms and percolates were measured after 3, 6, and 12 weeks. Earthworm activity did not affect metal availability of any treatment over time, but Ni and Cu concentrations in D. veneta were higher at the highest treatment levels. Earthworm Zn concentrations were similar in all treatments while Cr concentrations increased with increasing soil total metal content only for sludge treatments. Existing relationships of earthworm metal concentrations with total metal content in soil, taken from the literature, were not able to predict the metal levels measured in D. veneta. Results demonstrated that although over 12 weeks earthworm activity did not affect metal availability in soil, their burrowing activities did influence the metal concentrations of percolates over time.  相似文献   

3.
The study was conducted on Dendrobaena octaedra—a small epigeic earthworm species common in different forest types. In the laboratory the P (parent animals collected in forest) and F1 generations were cultured separately in containers filled with 50 g artificial soil. The containers were kept at 15±0.5 °C, 80% humidity and constant artificial light of low intensity. Every month during the 47 months of culture, the animals and cocoons were removed from the soil by washing on a sieve, weighed, and replaced into new soil. Individuals of the F1 generation did not reproduce continuously. Cocoon production was seasonal, despite culture in constant conditions throughout the whole experiment. Reproduction was highest in spring and summer, and dropped in the winter months. Seasonality characterized the fraction of animals reproducing as well as the number of cocoons produced. The observed seasonal changes in the cocoon production of the F1 generation cultured in constant conditions suggest that internal regulation of reproduction may exist in the earthworm D. octaedra. External factors like temperature, moisture, photoperiod or food supply, which could be responsible for seasonality of reproduction were missing.  相似文献   

4.
We have shown previously that riboflavin is stored in chloragosomes of chloragocyte-derived earthworm eleocytes what may have an adaptive value for worms vulnerable to soil-derived pathogen invasion. Thus, it is important to determine whether riboflavin stores are also present in earthworm species with low eleocyte counts, especially in the chloragocytes of their chloragogen tissue that surrounds the coelomic site of the intestine, and find out its putative roles in earthworm immunity. Experiments were performed on adult worms from 6 species. Freely floating coelomocytes (consisting of amoebocytes plus species-specific numbers of eleocytes) were extruded by mild electric shock and then chloragocytes from the same anaesthetized worm were mechanically detached into buffer. Both cell suspensions were analyzed by spectrofluorometry for riboflavin content. It turned out that riboflavin is stored in species-specific quantities in all investigated species. Riboflavin storage predominates in free coelomocytes of eleocyte-rich species (Eisenia andrei, Dendrobaena veneta, Allolobophora chlorotica) while in chloragocytes of species with few eleocytes (Lumbricus terrestris, L. rubellus, and Aporrectodea caliginosa). Upon a massive microbial impact, the coelomocytes (both amoebocytes and eleocytes) are involved in the formation of multicellular bodies encapsulating soil-derived pathogens, what is connected with enhanced coelomocyte mobility. Thus the second aim of the present investigation was to check if riboflavin can participate in coelomocyte accumulations. Tests performed in a 48-well chemotaxis chamber revealed that riboflavin behave as chemoattractant for coelomocytes of all investigated earthworm species, which may be one of mechanisms underpinning its immunomodulatory functions.  相似文献   

5.
The riboflavin content in extruded coelomocyte lysates derived from Dendrodrilus rubidus may serve as a sensitive bioindicator of soil metal pollution: the vitamin (B2) content has previously been found to be high in worms from unpolluted soil but low in worms inhabiting Zn/Pb mine soils, aerially deposited Ni-contaminated soil, and in worms experimentally transferred from clean soil to the metalliferous field soils. The aim of the present work was to extend these observations by comparing the number and riboflavin composition of coelomocytes retrieved from three lumbricid species (Allolobophora chlorotica, Dendrobaena veneta, Eisenia andrei) after 4-week exposures to an unpolluted commercial soil, two geochemically contrasting unpolluted field soils, and two different Zn/Pb/Cd-polluted soils from the Bukowno district in South Poland. Whilst eco-physiologically contrasting, these three earthworm species share the trait of possessing relatively high numbers of eleocytes, a category of immune-competent coelomocyte rich in autofluorescent riboflavin. Spectroflurometric analysis indicated that coelomocyte riboflavin content in worms maintained in strongly metalliferous soils or in unpolluted sandy-clay and loamy-sand soils was increased in coleomocytes from epigeic D. veneta and E. andrei species, whilst was decreased in endogeic A. chlorotica. In conclusion, the riboflavin content of earthworm coelomocytes is affected in species-specific ways by edaphic variables, including organic matter and metal pollution.  相似文献   

6.
Sublethal effects of terbuthylazine and carbofuran on the growth and reproduction of Eisenia andrei were investigated over a period of three generations. Reproduction was assessed by measuring the coccon production of worms treated chronically with pesticides. Inhibition of cocoon production was found in the parental generation. Hatchlings were raised from cocoons to provide the F1 generation. During raising a more rapid growth of juveniles treated with terbuthylazine was observed, compared with the growth of untreated worms. The increase in vitality was also found in cocoon production. Groups treated with terbuthylazine produced more cocoons than controls. The F2 generation was raised from hatchlings of the F1 generation, and here, also the terbuthylazine treatments increased earthworm growth, but not cocoon production. Exposure to carbofuran decreased cocoon production in all generations. Growth of the F1 generation was not influenced by low concentrations of carbofuran.  相似文献   

7.
《Applied soil ecology》2007,35(3):566-581
Defined and standardised media for the investigation of growth and reproduction of earthworms from a juvenile stage have been developed, but still retain a measure of components that are difficult to characterise completely. A defined medium, based on vermiculate, cellulose, humic acid and other components that are commercially available, and that supports growth and reproduction of E. fetida, added as juveniles, has previously been developed. However, one of the nutrients is not available anymore, and modifications were required. A series of various combinations were evaluated using commercially available nutrients such as fatty acids, organic phosphates and oxy-humic acids. All of the media supported growth (excepting one containing creatinine), but cocoons were only produced in some. It was shown that the growth and reproduction of E. fetida could be studied in a defined medium for up to 70 days (starting with 20-day old juveniles) without additional feeding. The various defined media reported here can be adopted to study specific aspects of earthworm biology and ecotoxicology in the laboratory, but would not replace the existing OECD methods.  相似文献   

8.
We studied the effects of maize residue application on some life-cycle parameters of the earthworm Aporrectodea trapezoides in saline agricultural soils with electrical conductivity (EC) ranging from 1.58 to 7.35 dS m−1. This experiment was carried out under controlled laboratory conditions for 150 days. Results showed that soil salinity significantly affected the growth and reproduction of earthworms, decreasing survival, numbers and mean fresh weights of adults, juveniles and cocoons. Maize residue application gave a greater survival of earthworms at all salinity levels, but the differences were only significant at an EC of 7.35 dS m−1, although the mean weight of adult earthworms was significantly increased by maize residue application at all salinity levels. At an EC of 1.58 dS m−1 and 3.35 dS m−1, the application of maize residues gave significantly higher numbers of cocoons and juveniles, but in soils with 5.26 dS m−1 and 7.35 dS m−1 earthworms did not produce any cocoons over the experimental period, irrespective of maize residue application. These results indicated that maize residue application alleviated the negative effects of soil salinity on the growth and reproduction of A. trapezoides up to 3.35 dS m−1, above which maize residues only increased the growth but not on the reproduction of earthworms.  相似文献   

9.
Wormcasts of Allolobophora caliginosa have been shown to have higher phosphatase activity than occurs in uningested soil, resulting in an increase in inorganic P released by mineralization of organic P. This paper describes similar observations on organic wastes which may be used for vermiculture. Besides A. caliginosa, three species which will feed on dung or other organic substrates were investigated, Eisenia foetida, Dendrobaena veneta and Lumbricus rubellus. When cow dung was used as a substrate, background phosphatase activity was too high for the effects of earthworm activity to be detected and a culture medium was therefore developed from sterilized paper waste sludge with added phytin. Phosphatase activity, assayed by a modified Hoffman method, was higher in the presence of all four earthworm species than in controls. It showed two peaks in relation to pH, at 3–5 and 9–10. The former is attributed to microbial activity and the latter to microbial activity or earthworm alkaline phosphatase. After 1 month, cultures of paper waste sludge with phytin contained about twice as much water soluble P when worms were present than in their absence.  相似文献   

10.
Many aspects of the reproduction and mating behaviour of earthworms remain poorly understood. In this study, we focused on body size as a possible trait that influences earthworm reproduction and mating processes. Eisenia andrei is a simultaneously hermaphroditic animal with reciprocal insemination and many hermaphrodites are expected to mate not primarily to get their own eggs fertilized, but rather to get the opportunity to fertilize the eggs of their partners. We investigated whether E. andrei has a size-dependent sex allocation, i.e. if larger earthworms are more biased toward female allocation and produce more egg mass and whether E. andrei has a size-related mate choice by studying the relationship between mating delay and cocoon production. To test this, we compared cocoon production between pairs of earthworms of equal and different size. Mature individuals of E. andrei were classified in two size classes (small and large) and we performed a two-factorial experiment with earthworm size and the size of the partner as factors. After copulation, earthworms were isolated and thereafter their mass and the number of cocoons they produced were recorded weekly for 18 weeks. We found no evidence of size-dependent sex allocation and we found no effect of size-assortative mating on cocoon production. With respect to the differences in the time to mate, the mating delay seems to indicate the existence of some kind of mate choice, independent of the earthworm size. Those earthworms that were matched sooner laid many cocoons, but those that waited a long time to mate laid fewer cocoons. This effect was stronger in those individuals paired with large partners, suggesting that some large partners are more desired ‘males’ than others; the reason for this remain as an open question. In general, our results confirm that earthworms are able to discriminate their partners and adjust their breeding effort accordingly.  相似文献   

11.
 The life cycle of Perionyx excavatus has been studied and the potential of this epigeic earthworm species for breaking down and processing organic wastes is well known. Understanding of its optimal environmental requirements is required in order to optimize and accelerate the vermicomposting process. The rates of growth and reproduction of P. excavatus, on a variety of organic wastes, were evaluated in these experiments. The time of maturation and the rates of growth of this species, under various population density pressures and temperatures between 15  °C and 30  °C, were also assessed. Increasing temperatures up to 30  °C accelerated the growth of earthworms and lessened the time to sexual maturity. However, the highest rates of reproduction occurred at 25  °C both in cattle solids and sewage sludge. The mean time to egg hatching decreased and the degree of hatching success increased with increasing temperature. Earthworms grew at similar rates in cattle solids, pig solids and aerobically digested sewage sludge, but the earthworms did not grow well in horse solids and grew only poorly in turkey wastes. The maximum individual growth rates as a function of earthworm population and the maximum earthworm weights as a function of time with a constant food supply at four different temperatures were assessed. Received: 16 July 1997  相似文献   

12.
A microcosm experiment was performed to investigate the effects of post-harvest potato tubers from transgenic cyanophycin-producing potatoes on Lumbricus terrestris (L.) activity and biomass, number of cocoons and their hatchability as well as the remaining cyanophycin content in soil and cast samples during a period of 80 days. Potato tubers from four transgenic potato events with different cyanophycin content in a range from 0.8 to 7.5% were compared to the near isogenic, non-transgenic control (Solanum tuberosum L. cv. Albatros) and a comparative potato cultivar (S. tuberosum L. cv. Désirée). One treatment with transgenic tuber residue but without earthworms was prepared as an additional control. Potato tuber loss from the surface of the microcosms was significantly higher in the treatments with transgenic potato tubers compared with non-transgenic treatments. It can be estimated that the earthworm contribution to potato tuber loss from the soil surface was approximately 61%. Mean number of cocoons in addition to the number of hatched cocoons varied from 2.6 to 6.2 and from 7 to 15 accounting for 45.2–83.35% hatchability, respectively, but no significant differences between the treatments were found. The same was true for the development of earthworm biomass in the various treatments. The cyanophycin content in soil samples was significantly higher when earthworms were present indicating that the cyanophycin content in the upper soil layer might have been enhanced through earthworm burrowing activity. Overall, it is concluded that tubers from transgenic cyanophycin potatoes are easily degradable and neither inhibit nor stimulate earthworm growth, reproduction, and activity.  相似文献   

13.
Applications of sewage sludge and lime have been used to restore some of the nearly 1.0 million ha of unreclaimed acid mine spoils in the United States. Earthworms might also aid in the reconstruction of mine spoils, but the earthworm response to mine spoils and sludge has not been widely studied. The objective of the present study was to examine growth of the earthworm Lumbricus terrestris in pots containing acidmine spoils, sewage sludge, and lime, and the growth of two common reclamation grasses, timothy (Phleum pratense L.) and tall fescue (Festuca arundinacea Schreb.), to the addition of earthworms. After 10 weeks, earthworms growing in the mine spoil treated with sewage sludge showed an increase in mean specific mass of 26.9% and in projected specific area of 24.5%. In contrast, earthworms growing on mine spoils without sludge decreased in mass by an average of 39.6% and in area by 21.0%. Soil pH influenced earthworm area, but not mass: earthworms growing on mine spoils (with or without sludge) showed an increase in mean surface area of 2.9% at pH 5.3 and a decrease of 11.2% at pH 6.5. The presence of earthworms significantly increased the belowground production of plant roots, but had no effect on either soil bulk density or above-ground production of plant biomass. The addition of earthworms to acid mine spoils treated with sewage sludge and lime might aid in the redevelopment of soil quality and biological diversity.  相似文献   

14.
《Applied soil ecology》2007,35(3):461-472
The reproduction test with the collembolan Folsomia candida is used as a tool to evaluate the ecotoxicological potential of organic wastes currently applied to soil. Seven organic wastes (dewatered sewage sludges, thermally dried sewage sludges, composted sewage sludges, and a thermally dried pig slurry) were tested. These wastes had different origins, treatments, and pollutant burdens, and were selected as a representative sample of the wide variety of wastes currently generated. F. candida showed varied sensitivity depending on the waste, but also depending on the endpoint assessed. Reproduction was more sensitive than survival, although no correlations between reproduction and physico-chemical parameters and pollutant burden could be found. On the other hand, mortality was directly related to the lack of stability of wastes, probably reflecting the toxicity of end-products such as ammonium. Body length was not shown to be a sensitive endpoint for waste testing, as it was neither affected nor even stimulated by waste concentrations.Organic matter, pH, and electrical conductivity varied with waste concentration in soil-waste mixtures, although their effect on collembolan performance was expected to be low and part of the complex effect exerted by wastes when applied to real soils. Selection of the water content is the most problematic aspect in waste testing, as it may affect the performance of test organisms. In this study, a qualitative approach for water content selection in waste testing was considered to be the most suitable.Treatment of wastes affected composition and toxicity. Composting of sewage sludge increased its stability, compared to the initial sludge, but decreased its non-persistent organic pollutant burden and toxicity. On the other hand, thermally dried wastes from sludge and pig slurry displayed high toxicity, mainly attributable to their low stability. The results from the study indicate the inability of chemical methods to predict the effects of complex mixtures on living organisms with respect to ecotoxicity bioassays, but also the need for stabilization treatments of organic wastes prior to their reuse in soils.  相似文献   

15.
The effect of different residual bulking agents (paper, cardboard, grass clippings, pine needles, sawdust and food wastes) in mixtures with sewage sludge (1:1 dry weight) on the growth and reproduction of Eisenia andrei, Bouché 1972 was studied in smallscale laboratory experiments with batches of sixty earthworms. The maximum weight achieved and the highest growth rate were attained in the mixture with food waste (755±18 mg and 18.6±0.6 mg day−1 respectively) whereas the smallest size and the lowest growth rate was achieved in the mixture of sewage sludge with sawdust (572±18 mg and 11±0.7 mg day−1 respectively). The earthworms showed much higher reproductive rates in the paper and cardboard mixtures (2.82±0.39 and 3.19±0.30 cocoons earthworm−1 week−1 respectively) compared to the control with sewage sludge alone (0.05±0.01 cocoons earthworm−1 week−1).  相似文献   

16.
采用塑料温棚内垄式堆积污泥培养蚯蚓方式,研究了蚯蚓处理对污泥重金属的影响。结果表明,污泥经蚯蚓处理后,理化性质发生了显著的变化,污泥的pH值、有机质、总氮和总磷都有不同程度的降低;蚯蚓能吸收富集污泥中的重金属,其中对重金属Cd有较强的富集能力;蚯蚓处理使污泥中重金属含量均出现不同程度的下降,重金属Cr、Zn、Pb、Cd、Cu、Ni分别减少27.98%、31.46%、32.81%、13.85%、23.86%和22.92%。利用盆栽试验,研究了污泥施用于土壤后生菜体内重金属积累的情况,结果表明,生菜体内重金属Zn、Cu、Pb和Ni的含量为污泥处理高于蚓粪处理;Cr和Cd则分别为差异不显著和略有降低。  相似文献   

17.
The present study was conducted to assess the suitability of sewage sludge amendment in soil for Beta vulgaris var. saccharifera (sugar beet) and Triticum aestivum (wheat) by evaluating the arsenic and selenium accumulation and physiological responses of plants grown at 10%, 25%, and 50% sewage sludge amendment rate. Sewage sludge amendment was modified by the physicochemical properties of soil, thus increasing the availability of heavy metals in the soil and consequently with higher accumulation in plant parts. The chlorophyll contents increased after the sewage sludge treatments except for 50%. The sewage sludge amendment led to a significant increase in arsenic and selenium concentrations of the soil. The heavy metal accumulation in the soil after the treatments did not exceed the limits for the land application of sewage sludge recommended by the US Environmental Protection Agency. The increased concentration of heavy metals in the soil due to the sewage sludge amendment led to increases in heavy metal uptake in the leaves and root concentrations of arsenic and selenium in plants as compared to those grown on unamended soil. Accumulation was more in roots than shoots and leaves for most of the heavy metals. Concentrations of arsenic and selenium were more than the permissible limits of national standards in the edible portion of sugar beet and wheat grown on different sewage sludge amendments ratios. The study concludes that the sewage sludge amendment in the soil for growing sugar beet and wheat may not be a good option due to risk of contamination of arsenic and selenium.  相似文献   

18.
通过单细胞凝胶电泳实验研究了不同浓度莫能菌素暴露对赤子爱胜蚓（Eisenia fetida）体腔细胞DNA的损伤,结果显示,50mg.kg-1莫能菌素处理组尾部DNA含量值最大、尾长值最大、Olive尾矩值最大,分别为34.539%、107.736μm和29.354;随着莫能菌素暴露剂量的增加,尾部DNA含量、Olive尾矩和尾长损伤频率增加;尾部DNA含量对莫能菌素暴露最为敏感,对照组和各处理组的尾部DNA含量之间均存在显著性差异（P〈0.05）;对照组与15、25、50 mg.kg-1处理组的Olive尾矩和尾长损伤频率之间均存在显著性差异（P〈0.05）;暴露浓度与尾部DNA含量、Olive尾矩和尾长具有良好的剂量-效应关系（P〈0.05）。实验结果表明,蚯蚓体腔细胞DNA损伤可作为指示莫能菌素影响的生物标志物,彗星试验是检测莫能菌素暴露对赤子爱胜蚓活体基因损伤的有效手段。  相似文献   

19.
Earthworm immune-competent cells (coelomocytes) can be adversely affected by soil metal contamination. The aim of the present paper was to perform comparative studies on the coelomocytes of four lumbricid species dermally exposed for 2 days to filter paper soaked with Ni, Cu, Zn, Cd, or Pb chlorides (1 mM). Coelomocytes were expelled by electro-stimulation, counted, and assayed ex vivo by flow cytometry and spectrofluorometry. The coelomocytes of Allolobophora chlorotica and Dendrobaena veneta contain both amoebocytes and riboflavin-storing eleocytes; consequently, they were subjected to assays based on flow cytometric quantification of autofluorescent eleocytes and spectrofluorometric measurement of riboflavin content in coelomocyte lysates. In Al. chlorotica, the number of coelomocytes, the percentage of eleocytes, and the amount of riboflavin were significantly lower in Cu-exposed worms although these cytometric parameters were less affected by Ni, Zn, Cd exposure, and entirely unaffected by Pb exposure. In D. veneta, such cellular effects were also only observed in Cu-exposed worms. The coelomic fluids of Aporrectodea caliginosa and Lumbricus rubellus are constitutionally impoverished of eleocytes; therefore, these species could not be subjected to assays measuring the riboflavin content of these granular cells. Rather, the amoebocytes of Ap. caliginosa and L. rubellus were subjected to flow cytometric measurements of in vitro neutral red uptake (NR). However, the NR uptake assay was technically demanding, requiring a strictly normalized incubation period over all samples to yield useful comparative data. In contrast, the riboflavin content in the coelomocyte lysates of eleocyte-rich species appears to be a robust and convenient immune-function biomarker of environmental stress.  相似文献   

20.
Earthworms can be troublesome pests on golf courses when their soil-rich casts become abundant enough to disrupt the maintenance, aesthetics, and playability of putting greens and fairways. Management of the problem is hindered by lack of knowledge of earthworm community structure on North American golf courses. We surveyed communities of endogeic earthworms inhabiting golf course fairways and putting greens in central Kentucky and tracked the seasonal population structure and casting activity of the predominant species. Seven earthworm species, six of them non-native, were identified in varying proportions from fairways of the different golf courses. Aporrectodea trapezoides (Dugès) dominated, although Allolobophora chlorotica (Savigny), Diplocardia singularis (Ude), and Amynthas sp. also were abundant on some courses. Soil characteristics (pH, percentages of sand, silt, clay, and organic matter) at fairway sample sites were not good predictors of overall earthworm density or proportionate abundance of particular species. Ap. trapezoides was found in the upper 21 cm of topsoil throughout the year except when frozen ground precluded sampling. The Ap. trapezoides population consisted mainly of adults and cocoons in late autumn and winter, and juveniles in summer. Casting by Ap. trapezoides, which also occurs on soil-based greens, was greatest in late autumn and early winter, with a secondary peak in early spring. Amynthas hupeiensis, an east Asian megascolecid earthworm, was the only species found damaging sand-based greens. Prolific casting by Am. hupeiensis continued during summer after other species’ casting activity on fairways had waned. Am. hupeiensis is established along river banks in Kentucky and neighboring states, and is used as fish bait. We hypothesize that it may be introduced onto golf courses as cocoons in river sand used for course renovations, or from bait discarded by anglers fishing in golf course ponds.  相似文献   

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