Cocoon Viability Research Articles

Environmental fate of dibutylphthalate in agricultural plastics: Photodegradation, migration and ecotoxicological impact on soil

Phthalic acid esters (PAEs) were determined in polyethylene covers used in horticultural production units located at Moreno and La Plata districts (Buenos Aires, Argentina), detecting 0.69–8.75 mg PAEs kg−1 plastic in greenhouse and tunnel films. The PAEs found were diisobutylphthalate (DIBP), dibutylphthalate (DBP) and diethylhexylphthalate (DEHP). DBP was chosen as a model molecule to carry out the photochemical degradation studies that led to the formation of monobutylphthalate (MBP) and phthalic acid (PA).DBP, MBP and PA migration from plastic covers was studied, finding that while DBP and MBP moved to soil and atmosphere in short times (<48 h), PA remained in the agricultural covers. Further experiments with DBP were made to explore the effect on migration of temperature (20 °C, 50 °C), film thickness (25 μm, 100 μm) and plastic ageing by solarization, observing that temperature increase, film thickness reduction and ageing by solarization favored DBP migration to the environment.DBP and MBP impact on soil were evaluated by avoidance and reproduction tests using Eisenia andrei as bioindicator. Both compounds reduced cocoon viability decreasing the number of juveniles at the lowest concentration assayed (0.1 mg kg−1 of soil). At higher DBP and MBP concentrations the reproductive parameters (number of total cocoons, hatchability and number of juveniles) also showed alterations compared with the controls. Carboxylesterases (CaE), cholinesterases (ChE) and glutathion-S-transferases (GST) activities were analyzed in E. andrei exposed to DBP; cholinesterases activities were reduced at 1 and 10 mg DBP kg−1 soil, and glutathione S-transferases activities were increased at 10 mg DBP kg−1 soil while no effect was observed on carboxylesterases activities.These results emphasize the need to continue studying the impact of PAEs and their photodegradation products on the environment.

Inhibitory Effect of Carbofuran Furadan 3G on the Cocoon Production and Viability in Pheretima javanica Gates

Though carbofuran has known to possess adverse effects in soil organisms including earthworms, little is known about the effects of carbofuran, either dirrectly or indirrectly, on the earthworm Pheretima javanica. This study aimed to investigate the effect of carbofuran at sublethal doses on the cocoons production and viability of Pheretima javanica worms. Six groups of earthworms, each consisted of four worms, were reared in plastic pots and fed on cow manure mixed with carbofuran as much as 0 mg (for control), 0.1mg , 0.2mg, 0.3mg, 0.4mg and 0.5mg repectively. Cocoons produced were hand sorted every two weeks for three months and presented as the number of cocoons per individual per moth. Cocoon viability was determined by observing the hatchling emerged from the cocoons incubated in Petri dish and expressed as percentage of viability. The results showed both cocoons production and cocoon viablity of the worms decreased significantly by the increasing concentration of the pesticide given (α = 0.05). Thus, it can be conclusively suggested that carbofuran (Furadan 3G) highly harmful to earthworm Pheretima javanica, even at low concentrations adversely affect growth and reproduction of the worms.

Viruses of managed alfalfa leafcutting bees (Megachille rotundata Fabricus) and honey bees (Apis mellifera L.) in Western Canada: Incidence, impacts, and prospects of cross-species viral transmission

We examined whether alfalfa leafcutting bees (ALCB, Megachille rotundata) experienced a higher incidence of seven viruses commonly found honey bees (Apis mellifera) when placed alongside honey bees for hybrid canola seed pollination. Although two viruses – sacbrood virus (SBV) and deformed wing virus (DWV) – were detected in ALCB adults, their presence appeared independent of whether honey bees were present in the same field or not. A further survey of viruses among ALCB adults in three different alfalfa seed growing regions in Western Canada confirmed the ubiquity of sacbrood virus (SBV) as well as the infrequent presence of acute bee paralysis virus (ABPV), both of which had not been previously reported on ALCB. Moreover, SBV and ABPV were detected in the cocoon stage and only in one region. Co-infection among pools of ALCB adults with both of these viruses was more closely correlated with decreasing levels of cocoon viability than infection levels in cocoons themselves. This research suggests ongoing viral transmission between honey bees and ALCB in the same fields is likely low but that co-infection with these viruses may lower ALCB productivity.

Chronic toxicity of commercial chlorpyrifos to earthworm Pheretima peguana

A chronic toxicity study was conducted in earthworms (Pheretima peguana) exposed to soil spiked with chlorpyrifos at concentrations of 0, 0.1, 1, 10, and 100 mg/kg soil dry matter for 7, 14, and 28 days. The integrity of the coelomocyte lysosomal membrane, nervous system, and male reproductive tissue was monitored using, respectively, the neutral-red retention assay, acetylcholinesterase (AChE) enzyme assay, and histomorphology of spermatogenic cells in the seminal vesicles and cocoon production (at 28 days after 28 days' exposure). Chlorpyrifos decreased the coelomocyte neutral-red retention time (NRRT) significantly (p < 0.05) at concentrations > 0.1 mg/kg soil as early as day 7 of exposure and was dose- and time-dependent. Chlorpyrifos inhibition of AChE activity was greater at day 7 than at day14 (p < 0.05) indicating possibly nerve recovery. Chlorpyrifos induced concentration-dependent damage to spermatogenic cells and cytophores in premature stages. The number and size of premature, maturing, and fully mature spermatogenic stages were increased at low concentrations (<1 mg/kg) but a number of these maturation stages declined at higher concentrations (10 and100 mg/kg) on day 28. The most severe effects were observed in the maturing and fully mature stages at the highest chlorpyrifos concentration, and this had an adverse impact on cocoon production and cocoon viability. Collectively, the results suggest induction of widespread effects on multiple organ systems in P. peguana exposed to chlorpyrifos. Although NRRT and AChE activity were the most sensitive of the biomarkers, cocoon production and cocoon viability could still be considered as diagnostic tools for monitoring effects from low-dose long-term chlorpyrifos toxicity and for evaluating population effects. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1450-1459, 2016.

Exposure assessment to glyphosate of two species of annelids.

Adult mortality, biomass, fecundity and viability of cocoons were studied in Eisenia fetida and Octolasion tyrtaeum, in response to glyphosate exposure in soil. Exposure tests were carried out following USEPA procedure, with five concentrations of glyphosate in soil and a control. O. tyrtaeum was more sensitive to the highest concentration of glyphosate (50,000 mg kg(-1)), with 100 % mortality by day 7 of exposure, compared with 71 % for E. fetida. Although biomass of O. tyrtaeum was significantly different between the control and 5,000 mg kg(-1) dose at day 14, E. fetida was not affected at that concentration, and only showed a significant weight loss after 7 days of exposure to 50,000 mg kg(-1). Adverse effects upon adult fecundity and cocoon viability were observed at glyphosate concentrations of 5,000 mg kg(-1) and above. Adverse effects were observed at concentrations that greatly exceeded the recommended field application rates of glyphosate.

Reproductive and behavioral responses of earthworms exposed to nano‐sized titanium dioxide in soil

Nanometer-sized titanium dioxide (nano-TiO(2) ) is found in a number of commercial products; however, its effects on soil biota are largely unknown. In the present study, earthworms (Eisenia andrei and Eisenia fetida) were exposed to three types of commercially available, uncoated TiO(2) nanomaterials with nominal diameters of 5, 10, and 21 nm. Nanomaterials were characterized for particle size, agglomeration, surface charge, chemical composition, and purity. Standard lethality, reproduction, and avoidance tests, as well as a juvenile growth test, were conducted in artificial soil or field soil amended with nano-TiO(2) by two methods, liquid dispersion and dry powder mixing. All studies included a micrometer-sized TiO(2) control. Exposure to field and artificial soil containing between 200 and 10,000 mg nano-TiO(2) per kilogram of dry soil (mg/kg) had no significant effect (p > 0.05) on juvenile survival and growth, adult earthworm survival, cocoon production, cocoon viability, or total number of juveniles hatched from these cocoons. However, earthworms avoided artificial soils amended with nano-TiO(2) . The lowest concentration at which avoidance was observed was between 1,000 and 5,000 mg nano-TiO(2) per kilogram of soil, depending on the TiO(2) nanomaterial applied. Furthermore, earthworms differentiated between soils amended with 10,000 mg/kg nano-TiO(2) and micrometer-sized TiO(2) . A positive relationship between earthworm avoidance and TiO(2) specific surface area was observed, but the relationship between avoidance and primary particle size was not determined because of the agglomeration and aggregation of nano-TiO(2) materials. Biological mechanisms that may explain earthworm avoidance of nano-TiO(2) are discussed. Results of the present study indicate that earthworms can detect nano-TiO(2) in soil, although exposure has no apparent effect on survival or standard reproductive parameters.

Life cycle studies of the earthworm Lumbricus friendi (Cognetti, 1904)

The objective of this work was to obtain data on aspects of the lifecycle of Lumbricusfriendi. Field-collected specimens from NW Spain were grown to maturity and maintained under controlled laboratory conditions. Thereafter experiments were undertaken to determine mode of reproduction, reproductive output, cocoon viability and development, and hatchling growth rate. Effects of density and temperature on growth were also examined. Plastic culture vessels containing a substrate of Kettering loam were incubated in temperature-controlled chambers, with dried horse manure as food. Paired, mature animals were sampled monthly over a period of 9 months for cocoon production. Cocoons were incubated on moist filter papers in Petri dishes. Results showed that at 15 °C, individuals matured at a live mass of 3.5 g. Zero cocoons were produced by virgin animals maintained in isolation, but recently matured, paired L. friendi produced 2.16 cocoons individual−1 wk−1. Cocoons were lemon-shaped with a smooth pale yellow-coloured outer surface and had a mean mass of 28 mg. At 15 °C, cocoons required 90 days to hatch and hatchability from the first 5 months of cocoon production was 85% successful. The majority of cocoons produced a single hatchling (twins recorded < 1%). Growth of hatchlings to maturity was achieved within a period of 5 months, with tubercula pubertatis developed after 3 months. Increased temperatures in the range of 5–15 °C led to significantly increased growth rates, whereas increased earthworm density led to a significant decrease in rate of growth. These findings permit comparisons with more closely studied anecic species such as Lumbricus terrestris.

As-resistance in laboratory-reared F1, F2 and F3 generation offspring of the earthworm Lumbricus rubellus inhabiting an As-contaminated mine soil

Previous studies provided no unequivocal evidence demonstrating that field populations of Lumbricus rubellus Hoffmeister (1843), exhibit genetically inherited resistance to As-toxicity. In this study F1, F2 and F3 generation offspring derived from adults inhabiting As-contaminated field soil were resistant when exposed to 2000 mg kg −1 sodium arsenate. The offspring of uncontaminated adults were not As-resistant. Cocoon viability was 80% for F1 and 82% for F2 offspring from As-contaminated adults and 59% in the F1 control population. High energy synchrotron analysis was used to determine whether ligand complexation of As differed in samples of: resistant mine-site adults, the resistant F1 and F2 offspring of the mine-site earthworms exposed to the LC 25 sodium arsenate (700 mg kg −1) of the F1 parental generation; and adult L. rubellus from an uncontaminated site exposed to LC 25 concentrations of sodium arsenate (50 mg kg −1). XANES and EXAFS indicated that As was present as a sulfur-coordinated species.

Allolobophora chlorotica (Savigny, 1826): Evidence for classification as two separate species

Breeding experiments have questioned the status of the green (g) and pink (p) colour morphs of Allolobophora chlorotica. Should they become regarded as separate species, the name Allolobophora virescens (Savigny, 1826) is available for the pink form of this earthworm. Breeding experiments were established to investigate the status of this species utilising previously unmated laboratory-reared adults. Pairs were set up for 10 days to facilitate mating, separated and then maintained in isolation for 28 days to obtain individual reproduction results. Cocoon production and viability were first determined from intra-morphic (p×p and g×g) and inter-morphic (p×g) pairings. All p×p and g×g pairings bred true with mean cocoon production in g×g (4.6 cocoons/worm/28 days) significantly greater (P<0.05) than in p×p (3.2 cocoons/worm/28 days). In p×g pairings, both pink and green individuals produced cocoons (3.9 and 5.9 cocoons/worm/28 days, respectively). However here, viability of cocoons produced by g was very low at 6%, compared with 59% for p. In a second experiment, previously unmated offspring from inter-morphic pairings (pg) were paired with like individuals (pg×pg) and also paired with pure bred pink (p1) and green (g1) individuals (p1×pg and g1×pg, respectively). All crosses produced cocoons. All cocoons produced by pg×pg crosses were non-viable. In p1×pg and g1×pg crosses the pg parent produced viable cocoons (64% and 79% viability, respectively) but cocoons produced by p1 and by g1 parents from these matings were 100% non-viable. It is suggested that severely restricted viability of cocoons produced by the green morph in p×g pairings provides evidence for genetic divergence of the 2 morphs. Furthermore, back-crossing of hybrids (pg) with pure bred morphs has indicated that hybrids are male sterile.

Growth and Reproduction of Earthworms in Ultramafic Soils

Ultramafic soils are characterized by high concentrations of heavy metals of natural origin-such as chromium, cobalt, manganese, and nickel-as well as a shortage of primary nutrients. This can result in extremely disadvantageous living conditions for all soil-dwelling organisms. Responses to these conditions were addressed by studying growth, cocoon production, and fecundity of earthworms as endpoints of sublethal effects and how this influences the reproductive system and, consequently, population development. Mature specimens of two ecophysiologically different species of earthworms, Eisenia fetida (Savigny) and Aporrectodea caliginosa (Savigny), were exposed for 56 days to an uncontaminated soil and ultramafic soils collected from six ultramafic sites in the Barberton greenstone belt. In all ultramafic soil samples, the specimens of both species grew slower than those in the control soil. In A. caliginosa, an autotomization of the tail section was observed at higher concentrations of heavy metals. At high levels of heavy metals such as manganese, chromium, nickel, and cobalt, a significantly lower cocoon production was recorded for E. fetida, and at medium levels, a time delay in cocoon production was found. A. caliginosa showed an increase in production at medium levels and a decrease at high levels of heavy metals. In both species, no correlation between growth and cocoon viability was found, indicating different target levels for toxicants present in ultramafic soils. To determine effects of these soils on population dynamics, hatching success may be a more useful endpoint of reproduction.

Life-cycle traits of the dimorphic earthworm species Allolobophora chlorotica (Savigny, 1826) under controlled laboratory conditions

Allolobophora chlorotica exists as two colour morphs, pink and green. Field observations have indicated that the two morphs have ecological preferences linked to soil moisture: the green morph dominating in wet soils and the pink morph in dry soils. The aim of this laboratory-based research was to investigate the potential differences in fitness and adaptation to soil-moisture conditions of the two morphs measured in terms of growth rate, reproductive output and cocoon viability. An initial experiment maintained hatchlings of both morphs individually under standard culture conditions. On maturation, these were paired (intra-morph), and cocoon production, viability and incubation time were determined. The green morph had significantly faster (P 0.05) by soil moisture. In contrast, lower soil-moisture content significantly (P < 0.05) slowed growth and maturation of the green morph. These results support field observations relating to distribution of the two A. chlorotica colour morphs. We suggest that soil-moisture content may act to isolate these morphs, providing, in extremes, a barrier to inter-morphic mating.

Culture techniques for soil dwelling earthworms: A review

Developments in ecotoxicology and soil restoration have led to an increase in earthworm research over the past 20 years. Rearing of earthworms under laboratory conditions has therefore become desirable, but perceived difficulties have beset this practice. A review of recent research on the development of earthworm culture techniques for temperate, soil dwelling (anecic and endogeic) species is presented. Critical abiotic and biotic factors including soil moisture, organic matter, temperature, pH, earthworm density and species composition are considered, and optimal values provided for four species ( Allolobophora chlorotica, Aporrectodea caliginosa, Aporrectodea longa and Lumbricus terrestris ). Published figures relating to growth to maturity, cocoon production and cocoon viability, for these frequently studied species are collated and advice offered for culture of other soil dwelling species.

Life history characteristics of Lumbricus terrestris and effects of the veterinary antiparasitic compounds ivermectin and fenbendazole

Earthworms in pastureland may be exposed to residues of veterinary medicines excreted in the faeces of treated cattle. Possible sub-lethal effects of these drugs on life history characteristics are critical to earthworm populations, but there are no internationally accepted guidelines for the laboratory testing that is essential as a supplement to field studies. In the laboratory, Lumbricus terrestris were kept in artificial soil and offered dung collected from cattle with sustained-release boluses of ivermectin or fenbendazole, or from untreated cattle (control). Earthworms were therefore exposed to drug residues in concentrations excreted naturally by treated cattle. Furthermore, worms were exposed to the drug in the natural way, i.e. by ingestion. A matrix model based on survival and reproductive rates as functions of life-stages was used to quantify the population dynamics of L. terrestris. There were no adverse effects of either ivermectin or fenbendazole on the individual survival and growth of L. terrestris. Mature worms produced on average 2–3 cocoons per worm per month irrespective of drug treatment, and about 50% of these cocoons hatched successfully. The median time to hatching (incubation time) depended on the age of the parent worms and was significantly lower for cocoons in the ivermectin group compared to controls, as the worms became older. The incubation time varied considerably in all groups; even within a batch of cocoons produced during 1 month by one pair of worms, the period sometimes varied by more than 1 year. The intrinsic rate of natural increase ( r≈0.0044 d −1) was not affected by either drug treatment. The methods and the model developed in this study are suitable for long-term studies on L. terrestris and give ecologically relevant information on population dynamics. There were no negative effects of ivermectin and fenbendazole on life history characteristics of L. terrestris and it is unlikely that earthworm populations will be affected in the field following normal use of sustained-release boluses in cattle. Finally, the matrix model points to adult survival rate and cocoon viability as the most important variables to be included in future ecotoxicological tests on L. terrestris.

Uniparental reproduction of Eisenia fetida and E. andrei (Oligochaeta: Lumbricidae): evidence of self-inseminationThe 7th international symposium on earthworm ecology · Cardiff · Wales · 2002

Summary This study investigated the copulatory behaviour of the lumbricid earthworm Eisenia fetida (Savigny, 1826) in a natural population, and the uniparental reproduction of E. fetida and E. andrei Bouche 1972, two closely-related species. Sperm transfer occurred in 61% of the matings observed, of which 88.2% showed bi-directional sperm transfer, 9.8% unidirectional sperm transfer and one earthworm was self-inseminating. Although uniparental reproduction in earthworms has been reported by many authors, self-insemination has never been recorded before this study. Moreover, specimens of the two species were reared in isolation from hatching to see if they were able to produce cocoons when clitellate. The percentage of earthworms that produced cocoons was significantly higher in E. andrei (33%) than in E. fetida (3.5%). Numbers of cocoon produced and the number of hatchlings per cocoon were also significantly higher in E. andrei than in E. fetida ; the cocoon viability was similar in the two species. One of these isolated individuals of E. fetida that produced cocoons was dissected and sperm was found into the spermathecae, indicating that self-insemination could be responsible, to some extent, of uniparental reproduction. Since parthenogenesis has not been demonstrated in these species, further studies are needed to show if uniparental reproduction is due only to self-fertilization.

Uniparental reproduction of Eisenia fetida and E. andrei (Oligochaeta: Lumbricidae): evidence of self-insemination : The 7th international symposium on earthworm ecology · Cardiff · Wales · 2002

Summary This study investigated the copulatory behaviour of the lumbricid earthworm Eisenia fetida (Savigny, 1826) in a natural population, and the uniparental reproduction of E. fetida and E. andrei Bouche 1972, two closely-related species. Sperm transfer occurred in 61 % of the matings observed, of which 88.2 % showed bi-directional sperm transfer, 9.8 % unidirectional sperm transfer and one earthworm was self-inseminating. Although uniparental reproduction in earthworms has been reported by many authors, self-insemination has never been recorded before this study. Moreover, specimens of the two species were reared in isolation from hatching to see if they were able to produce cocoons when clitellate. The percentage of earthworms that produced cocoons was significantly higher in E. andrei (33 %) than in E. fetida (3.5 %). Numbers of cocoon produced and the number of hatchlings per cocoon were also significantly higher in E. andrei than in E. fetida; the cocoon viability was similar in the two species. One of these isolated individuals of E. fetida that produced cocoons was dissected and sperm was found into the spermathecae, indicating that self-insemination could be responsible, to some extent, of uniparental reproduction. Since parthenogenesis has not been demonstrated in these species, further studies are needed to show if uniparental reproduction is due only to self-fertilization.

A comparison of biomarker responses in the earthwormAporrectodea caliginosato the organophosphorus insecticides diazinon and chlorpyrifos

AbstractThree biomarkers inAporrectodea caliginosaSavigny were evaluated for their ability to detect exposure to organophosphorus insecticides, and these physiological responses were related to effects on growth and life‐table parameters. Adult and juvenile earthworms were exposed to a laboratory‐simulated field rate (low concentration) and a higher sublethal concentration of diazinon and chlorpyrifos. After a four‐week exposure, juveniles were evaluated for cholinesterase activity, glutathioneS‐transferase activity, and growth, and adults were evaluated for the lysosomal neutral red retention assay (NRRA) and growth. Cholinesterase activity and the NRRA were more sensitive than growth in each age group for detecting exposure to the pesticides. Life‐table parameters were evaluated in earthworms exposed as juveniles and as adults. Maturation was less sensitive to pesticides than was cocoon production. Growth and cocoon production in earthworms exposed as juveniles appeared to be more sensitive to organophosphorus insecticides than earthworms exposed as adults. Life‐table responses in juveniles may, therefore, be more predictive of long‐term impacts of organophosphorus insecticide applications on populations than responses in adults. Biomarker responses occurred at similar or lower concentrations than those causing an adverse effect on cocoon production and cocoon viability, indicating their usefulness in risk assessment for predicting ecologically relevant assessment end points.

Cocoon production and viability as endpoints in toxicity testing of heavy metals with three earthworm species

Summary This study compares the cocoon production and cocoon viability of three earthworm species, Eudrilus eugeniae, Perionyx excavatus and Eisenia fetida after exposure to a sublethal concentration of lead nitrate. Cocoon production in all three species did not differ significantly between exposed and control worms. However, cocoon viability in all three species was affected detrimentally by the presence of lead nitrate. Cocoons of Eisenia fetida from substrates contaminated by lead nitrate, cadmium sulphate and zinc sulphate for 36 months, also showed a lowered cocoon viability. It is concluded that cocoon viability may be a sensitive endpoint of sublethal toxicity of these metal salts.

The effects of low lead levels on the growth and reproduction of the African earthworm Eudrilus eugeniae (Oligochaeta)

The effects of sublethal concentrations of lead nitrate on the growth and reproduction of the African composting earthworm species, Eudrilus eugeniae, was studied by exposing worms in an organic substrate to lead-nitrate-contaminated food over a period of 76 days. The results revealed that growth was initially affected negatively by the presence of lead, while the maturation rate and cocoon production were not affected. In agreement with other studies on Eisenia fetida, cocoon viability was affected negatively by lead, making this a sensitive toxicity endpoint.

Effects of Low Levels of Lead on Growth and Reproduction of the Asian Earthworm Perionyx excavatus (Oligochaeta)

The effects of sublethal concentrations of lead nitrate on growth and reproduction of the Asian composting earthworm species Perionyx excavatus was studied experimentally by exposing worms in an organic substrate to lead nitrate-contaminated food over a period of 76 days. The results revealed that growth was affected negatively by the presence of lead while maturation rate and cocoon production was not affected. In agreement with other studies on Eisenia fetida, cocoon viability was affected negatively by lead, making this a sensitive toxicity endpoint. Lead accumulation was of the same order of magnitude as for other previously studied species.

Stimulating effects of low lead concentrations on growth and cocoon production ofEisenia fetida(Oligochaeta)

Earthworms form an important component of the soil biota in many soils and are very sensitive to various types of contaminants. Their protection may therefore provide a margin of safety for other fauna once comparative toxicological data are available. The effects oflead on growth, maturation, cocoon viability and cocoon production of the vermicomposting earthworm species Eisenia fetida were studied by exposing worms experimentally to a sublethal concentration of lead (2000 µg. g−1) for a period of 76 days. Growth rate as well as cocoon production were monitored every 14 days and cocoons were incubated to determine their hatching success. Lead content of worms was also analysed. Exposed worms grew noticably better and produced more cocoons than control worms. Cocoon viability was, however, affected detrimentally. It is concluded that, although lead is known to be toxic at higher concentrations, sublethal concentrations close to the predicted EC5a and NOEC-values have a stimulating or hormetic effect on gr...