Cocoon viability and evidence for delayed hatching by the earthworm Lumbricus terrestris in a laboratory-based study.

Clitellate Lumbricus terrestris, obtained from 5 commercial suppliers (A-E) and also field collected (F) - grassland in Preston, Lancashire, UK, were kept under controlled environmental conditions (15 °C and 24 h darkness) in a sterilised loam soil and surface-fed with horse manure. Survival, biomass and cocoon production was monitored every 4 weeks over 1 y. Collected cocoons were maintained in water-filled Petri dishes on filter paper. Time to hatch and cocoon viability was recorded over a 2 y period. Cocoon production ranged from 15.1 – 32.2 ind.-1 y-1. Cocoon production was initially low followed by a period of high production (12-36 weeks) and then fell (36-52 weeks). Time for cocoon hatching ranged from 132-731 days. Hatching success after 2 years was 58–90% across treatments, with a total viability (including cocoons dissected after the 2 year period) of 88-94%. Evidence of 2 distinct hatching peaks was recorded, separated by a period of approximately 12 months in treatments of most of the commercially obtained earthworms. Cocoon incubation periods are in excess of those previously recorded under similar laboratory conditions (e.g. 90–280 days). Furthermore, viability is also higher than previously recorded (e.g. 67.9–83%). These differences are mainly attributable to the extended length of cocoon observation. Origin, age, unknown pre-treatment (in A-E) and experimental conditions (e.g. a constant temperature regime) may have influenced incubation times. However, it is suggested that asynchronous and delayed hatching within cohorts and ability for cocoons to remain viable for extended periods allows this K-selected species to maximise reproductive potential. This proposed “bet-hedging” strategy is worthy of further laboratory and field-based investigation

An oasis of fertility on a barren island: Earthworms at Papadil, Isle of Rum

The Isle of Rum, Inner Hebrides, has an impoverished earthworm fauna as the soils are generally acidic and nutrient-poor. Species associated with human habitation are found around deserted crofting settlements subjected to “clearances” in the mid-19th century and at Kinloch, where a large volume of fertile soil was imported from the mainland around 1900. Earthworms, and the dew worm Lumbricus terrestris L. in particular, were investigated at Papadil, an abandoned settlement and one of the few locations on Rum where a naturally developed brown earth soil is present. The small (1.5 ha), fertile location is isolated, so was also suitable for field experimentation. Visits over six years allowed dew worm distribution to be assessed within low lying grassland and woodland and also within an adjacent sloping broadleaved woodland. The factors limiting dew worm distribution at the site were investigated with associated translocation to adjacent uninhabited areas. Small scale spatial dynamics were studied with density manipulation and containment experiments where Visual Implant Elastomer marking of individuals was utilised. Translocations from streamside woodland to adjacent grassland was successful over a short period (5 months), but the colonies did not persist over a longer term (5-6 years). Field trials with earthworm tagging were successful, but highest tag recovery rate was 25%. Where adults/sub-adults were removed, recruitment of juveniles was notable. Exceptionally large (>12 g live mass) individuals were found in soils of terraces on wooded slopes, suggesting that dew worms may be long lived at this location, where food is abundant and relatively few terrestrial predators are present

Earthworms of an urban cemetery in Preston: General survey and burrowing of Lumbricus terrestris.

Cemeteries in the UK are predominantly represented by grassland areas which have a variety of origins. Each can act as a haven for wildlife and numerous studies have looked at the flora and fauna present and in particular lichens associated with gravestones which offer chronological assessment. However, very few studies have looked at invertebrates in such settings and surprisingly, few if any have investigated earthworms - given the folklore associating these animals with the decomposition of human remains in the soil. This investigation set out to identify which species of earthworm were present in an urban cemetery in Preston and to discover how deep the animals were burrowing and indeed, if they were capable of burrowing to a depth of 2 metres – the depth at which bodies are usually buried. Nine species of earthworm were found, representing all three ecological categories, epigeic, endogeic and anecic. Burrow configurations were measured through casting with polyurethane resin. Vertical burrows of clitellate Lumbricus terrestris penetrated to a mean depth of 0.49 m (maximum 0.59 m), a function of soil type and water table. Where previous land use had created a relatively impervious layer below the soil surface, complex branched burrows of L. terrestris were found. These were significantly (p<0.001) shorter (mean depth 0.21 m) but confirmed the behavioural flexibility that this species of earthworm is known to exhibit. The presence of a healthy earthworm community in the grassland of the cemetery may well assist ecosystem services, but assistance with decomposition of human remains is unlikely

Interactions of juvenile Lumbricus terrestris with adults and their burrow systems in a two-dimensional microcosm

O objetivo deste trabalho foi avaliar as interações de juvenis de Lumbricus terrestris com indivíduos adultos e com sistemas de galerias herdados. O experimento foi realizado usando microcosmos bidimensionais de Evans como unidades experimentais. Adultos de L. terrestris foram colocados em 16 unidades experimentais (um indivíduo por unidade) e mantidos no escuro a 17ºC juntamente com oito unidades experimentais inabitadas, por dois meses. Os adultos foram removidos de oito unidades selecionadas aleatoriamente e juvenis foram adicionados a todas as unidades experimentais (um indivíduo por unidade), em três tratamentos, com oito repetições: 1, com um adulto em um sistema de galerias herdado (ABJ); 2, sozinho em um sistema de galerias herdado (BJ); e 3, sozinho em uma unidade experimental inabitada (J). A proporção de juvenis observados ocupando as galerias feitas pelos adultos foi significativamente diferente nos tratamentos ABJ (48%) e BJ (75%). A biomassa média dos juvenis ao final do experimento diferiu significativamente entre os tratamentos e foi maior no tratamento J (4.04±0.39 g) em comparação com os tratamentos BJ (3.09±0.93 g) e ABJ (2.13±0.64 g). Os resultados sugerem uma influência negativa tanto da presença de um adulto quanto do seu sistema de galerias no crescimento dos juvenis. A competição intraespecífica explica parcialmente este fenômeno, porém novas investigações devem ser feitas para examinar como um ambiente herdado (galerias) pode afetar negativamente o crescimento de juvenis.The objective of this work was to evaluate interactions of Lumbricus terrestris juveniles with adults and with inherited burrow systems. An experiment was set up using a two dimensional Evans' boxes microcosm. Adult L. terrestris were added to 16 boxes (one individual per box) and kept in darkness at 17°C along with eight unoccupied boxes for two months. The adult L. terrestris were removed from eight randomly selected boxes, and L. terrestris juveniles were added (one juvenile per box), composing three treatments with eight replicates: 1, with an adult in an inherited burrow (ABJ); 2, alone in an inherited burrow (BJ); and 3, alone in a previously uninhabited box (J). The proportion of juveniles occupying adult burrows observed was significantly different in treatments ABJ (48%) and BJ (75%). The mean mass of juveniles at experimental termination differed significantly among treatments and was greater in treatment J (4.04±0.39 g) in comparison to the BJ (3.09±0.93 g) and ABJ treatments (2.13±0.64 g). Results suggest a negative influence of both the presence of an adult and its burrow system on juvenile growth. Intraspecific competition partially explained this, but further investigation is required to examine how an inherited environment (i.e. burrow) could negatively affect the growth of juveniles

Assessment of avoidance behaviour by earthworms (Lumbricus rubellus and Octolasion cyaneum) in laboratory-based linear pollution gradients.

Avoidance behaviour by earthworms is recognised as a valuable endpoint in soil quality assessment and has resulted in the development of a standardised test (ISO 17512-1: 2008) providing epigeic earthworms with a choice between test and control soils. This study sought to develop and evaluate an avoidance test utilising soil-dwelling earthworms in linear pollution gradients with Visible Implant Elastomer (VIE) tags used to identify individual organisms. Sequential experiments were established in laboratory-based mesocosms (0.6 m x 0.13 m x 0.1 m) that determined the relative sensitivities (in terms of associated avoidance behaviour) of Octolasion cyaneum and Lumbricus rubellus at varying levels of polluted soil and also assessed the influence of introduction point on recorded movement within gradients. In an initial gradient (0, 25, 50, 75, 100% polluted soil), both species exhibited a clear avoidance response with all surviving earthworms retrieved (after 7 days) from the unpolluted soil. In a less polluted gradient (0, 6.25, 12.5, 18.75, 25%) L. rubellus were retrieved throughout the gradient while O. cyaneum were located within the 0 and 6.25% divisions, suggesting a species-specific response to polluted soil. Results also showed that the use of a linear pollution gradient system has the potential to assess earthworm avoidance behaviour and could provide a more ecologically relevant alternative to the ISO 17512: 2008 avoidance test. However, further work is required to establish the effectiveness of this procedure, specifically in initial chemical screening and assessment of single contaminant bioavailability, where uptake of pollutants by earthworms could be measured and directly related to the point of introduction and retrieval

Is tagging with visual implant elastomer a reliable technique for marking earthworms?

Visual implant elastomer (VIE) has recently been employed to investigate different aspects of earthworm ecology. However, a number of fundamental questions relating to the detection and positioning of the tag, its persistence and potential effects on earthworms remain unknown. Seven earthworm species belonging to three ecological groupings, with different pigmentation and burrowing behaviour, were tagged using different coloured VIE. External inspection after two days, one week and 1, 10 and 27 months were followed by preservation, dissection and internal inspection. Tags could be seen in living specimens to 27 months, and dissection revealed that in most cases they were lodged in the coelomic cavity, held in place by septa. However, over longer time periods (more than two years), the chlorogogenous tissue tended to bind to the tags and made external observation increasingly difficult. Migration of the VIE material towards the posterior of the earthworm and potential loss of the tag were only observed on rare occasions, and a recovery rate in excess of 98% was recorded. By introducing a reasonable amount of VIE into segments, just after the clitellum, this technique can become a valuable tool in earthworm ecology and life history studies, particularly in short-medium term laboratory and field experiments

Effects of silver nanoparticles on survival, biomass change and avoidance behaviour of the endogeic earthworm Allolobophora chlorotica

Increasing commercial application of silver nanoparticles (Ag NP) and subsequent presence in wastewater and sewage sludge has raised concerns regarding their effects in the aquatic and terrestrial environment. Several studies have employed standardised acute and chronic earthworm-based tests to establish the toxicological effects of Ag NP within soil. These studies have relied heavily on the use of epigiec earthworm species which may have limited ecological relevance in mineral soil. This study assessed the influence of Ag NP (uncoated 80 nm powder) and AgNO3 on survival, change in biomass and avoidance behaviour in a soil dwelling (endogiec) species, Allolobophora chlorotica. Earthworms were exposed for 14 days to soils spiked with Ag NP or AgNO3 at 0, 12.5, 25, 50 and 100 mg kg-1 either separately for survival and biomass measurement, or combined within a linear gradient to assess avoidance. Avoidance behaviour was shown to provide the most sensitive endpoint with an observable effect at an Ag NP / AgNO3 concentration of 12.5 mg kg-1 compared with 50 mg kg-1 for biomass change and 100 mg kg-1 for survival. Greater mortality was observed in AgNO3 (66.7%) compared with Ag NP-spiked soils (12.5%) at 100 mg kg-1, attributed to increased presence of silver ions. Although comparison of results with studies employing Eisenia fetida and Eisenia andrei suggest that the A. chlorotica response to Ag NP is more sensitive, further research employing both epigeic and endogeic earthworms under similar experimental conditions is required to confirm this observation

NASA Ares I Launch Vehicle First Stage Roll Control System Cold Flow Development Test Program Overview

The Ares I launch vehicle is the selected design, chosen to return humans to the moon, Mars, and beyond. It is configured in two inline stages: the First Stage is a Space Shuttle derived five-segment Solid Rocket Booster and the Upper Stage is powered by a Saturn V derived J-2X engine. During launch, roll control for the First Stage (FS) is handled by a dedicated Roll Control System (RoCS) located on the connecting Interstage. That system will provide the Ares I with the ability to counteract induced roll torque while any induced yaw or pitch moments are handled by vectoring of the booster nozzle. This paper provides an overview of NASA s Ares I FS RoCS cold flow development test program including detailed test objectives, types of tests run to meet those objectives, an overview of the results, and applicable lessons learned. The test article was built and tested at the NASA Marshall Space Flight Center in Huntsville, AL. The FS RoCS System Development Test Article (SDTA) is a full scale, flight representative water flow test article whose primary objective was to obtain fluid system performance data to evaluate integrated system level performance characteristics and verify analytical models. Development testing and model correlation was deemed necessary as there is little historical precedent for similar large flow, pulsing systems such as the FS RoCS. The cold flow development test program consisted of flight-similar tanks, pressure regulators, and thruster valves, as well as plumbing simulating flight geometries, combined with other facility grade components and structure. Orifices downstream of the thruster valves were used to simulate the pressure drop through the thrusters. Additional primary objectives of this test program were to: evaluate system surge pressure (waterhammer) characteristics due to thruster valve operation over a range of mission duty cycles at various feed system pressures, evaluate temperature transients and heat transfer in the pressurization system, including regulator blowdown and propellant ullage performance, measure system pressure drops for comparison to analysis of tubing and components, and validate system activation and re-activation procedures for the helium pressurant system. Secondary objectives included: validating system processes for loading, unloading, and purging, validating procedures and system response for multiple failure scenarios, including relief valve operation, and evaluating system performance for contingency scenarios. The test results of the cold flow development test program are essential in validating the performance and interaction of the Roll Control System and anchoring analysis tools and results to a Critical Design Review level of fidelity