Abstracts

 
Standardised tests for antiparaciticide environmental safety evaluation

Römbke, J., Lumaret, J-P., Scheffczyk, A. & Adler, N.

ECT Oekotoxikologie GmbH, Böttgerstr. Flörsheim, Germany.

Abstract

According to the European legislation, an environmental risk assessment of veterinary pharmaceuticals for dung fauna is required if the substance acts as an antiparasiticide for the treatment of pasture animals. However, the demonstration of the environmental safety of those substances for dung fauna was strongly hampered by the fact that no standardized tests were available until recently. Therefore, starting with recommendations from the SETAC advisory group DOTTS (Dung Organism Toxicity Test Standardization) test systems for phase II tier A tests on the mortality of dung fly and dung beetle larvae were developed and recently standardized (OECD 2008; OECD 2009). After briefly describing these new tests new developments in the area of dung beetle testing will briefly presented. Using the species Aphodius constans, the focus will be laid on two long-lasting test designs with chronic endpoints. In addition first results from tests with ivermectin performed in Flörsheim and Montpellier will be shown. The usage of these new tests in the context of the European registration process of pharmaceuticals will be discussed.

Do cattle wormers have a long-term impact on non-target insect fauna?

Olwen Williams

Open University

 

Abstract

In the course of a part-time PhD, I have attempted to investigate in the field the effects of three different approaches to cattle worming, comparing a spring bolus of Oxfendazole and a spring pour-on dose of Ivermectin with an organic ‘no treatment' regime.  Besides doing field counts of Scatophaga stercoraria (yellow dung flies), I have measured the hatching yield of Diptera, using emergence trapping, and the extracted yield of both Diptera and Coleoptera from dung pats.  Preliminary results indicate that both treatment regimes have adverse effects on dung-dependent insect fauna, though the timing of this varies.  However, even at times when the dung is inhospitable for development, the number of adult S. stercoraria present in the field does not vary with the treatment regime. This suggests that some dung-dependent insects may be sufficiently mobile to colonise fresh dung several kilometres away and raises the question whether treated dung may be acting as a sink for insects hatching elsewhere. 

Monitoring Farm and Regional Scale Effects of Anthelmintics and Endectocides

Martin, S.L., Wilson, P., Crout, N.M.J. & West, H.M.

School of Biosciences, University of Nottingham

 

Abstract

Routine use of worming drugs may be detrimental to non-target species living in cattle dung. We are surveying up to 80 farms in central England to evaluate veterinary drug use and monitor biodiversity of dung inhabitants. Outcomes of this project (funded by the Esmée Fairbairn Foundation) will include an update of patterns of drug use on farms, data sets of coprophilous insect abundance, and a computer-based decision aid aimed at farmers and conservationists. Further, current models that evaluate impacts of endectocide use on dung insect populations will be enhanced.

Alternative approaches to parasite control: are they less environmentally harmful?

S.A. Beynon

Supervisor: Dr Owen T. Lewis

Department of Zoology, University of Oxford, Oxford

 

Abstract

Unnaturally high stocking densities of farmed livestock make it necessary to treat animals with anthelmintics to control gastro-intestinal parasites. Many conventional treatments (anthelmintics) pass unaltered into the dung where they may exert an insecticidal effect on dung invertebrates and interfere with their function of dung decomposition. With an impoverished dung-insect community, dung pat removal time increases. The knock-on is a reduction in available grazing area and pasture soil nitrogen, creating a breeding site for parasites and pest flies. Additionally, parasite resistance to anthelmintics is a worldwide issue, and therefore both conventional and organic farmers are looking at alternative approaches of gastro-intestinal parasite control.  Alternative approaches include plants, micro-fungi, minerals and trace elements. Many are widely used, especially on organic farms. Apart from some work on the nematode-trapping fungus, Duddingtonia flagrans, no work has looked at the impact of these alternative treatments on dung invertebrates and their function.    The current study focuses on a suite of alternative approaches and asks whether these affect soil and dung invertebrates and if this links to an impact on the rate of pat decomposition. The presentation outlines the 2009 trials looking at commercially available or scientifically-trialed alternative supplements for parasite control, including Duddingtonia flagrans, Diatomaceous Earth, Verm-X, garlic, copper and a homeopathic product.

The effect of ivermectin on the cattle dung insect community under different environmental conditions

 

Jochmann, R. & Blanckenhorn. W.U.

Zoological Museum, University of Zurich, Switzerland

 

Abstract

The composition and diversity of the insect community of cattle dung can be influenced by several factors, including food regime of the dung-producing animal, climate and pharmaceutical residues contained in the dung. We assessed the community of cattle-dung associated insects under different environmental conditions by investigating 24 different pastures across Switzerland. These pastures differed in altitude and habitat and were situated in different regions, thus reflecting a broad range of environmental conditions. Four dung pats, half of them containing ivermectin at a concentration of 6.6 µg/kg, were placed on each of the pastures to be settled by dung insects, as well as four dung-baited pitfall traps, again half of the baits with ivermectin. This setup was repeated in spring, summer and autumn over two consecutive years.  Ivermectin had a pronounced effect in reducing biodiversity and changing the composition of the insect community. Some species groups were more affected than others. Several other factors also influenced the composition of the dung-community. We conclude that, in general, man-made pollutants such as livestock medication differentially affect the cow dung insect community,

Aggregation in insect communities colonizing cattle-dung

Richard Wall & Colin Lee

School of Biological Sciences, University of Bristol,

Abstract

Ruminant dung is a highly ephemeral, patchily distributed resource, which is used by a diverse community of invertebrate species.  In such environments high levels of insect aggregation may be important in facilitating stability and coexistence across patchily distributed populations. The aim of the present work was to quantify the aggregation of the insects colonising cow-dung in cattle pasture in South West England and test the hypothesis that the dung-pat community assemblage observed was the result of stochastic colonization.  This was examined using batches of ten standardised, 1.5kg, artificial cow pats placed out in cattle pastures in each of 24 weeks, between May and October in 2001.  Pats were left exposed in the field for seven days, before being brought back to the laboratory, where any insect colonizers were collected and identified.  Individual pats contained, on average, only half the number of insect taxa present in an entire batch put out at any one time.  All larval coleopteran taxa, 20 of the 22 adult coleopteran taxa and 22 of the 23 dipteran taxa showed significant aggregation, with the abundance of most taxa within pats approximating a negative binomial distribution.  A simulation analysis was used to show that the observed relative frequency of taxa within pats did not differ from that expected by chance if colonisation is a random binomial event in which each species colonises a pat independently of all other species.  Aggregated populations, of even highly abundant insects, may be more susceptible to the deleterious effects of insecticidal contaminants in dung than if they were evenly distributed, if by chance they colonize a pat containing insecticidal residues from a recently treated animal.

SHORT 5 MINUTE PRESENATIONS

 

Earthworm microhabitats - projections of the drilosphere?

Donovan, N., Jones, D.T., Briones, M.J.I.,  and Dungait J.A.J

North Wyke Research, Rothamsted Research Soil Cross Institute Programme, Okehampton, Devon

 

Abstract

Earthworms participate in soil functions through the drilosphere -  conceptually defined as the space of interactions among earthworms, soil or waste physical structure, and the whole microbial and invertebrate community (Lavelle et al, 1998). The processes of organic matter digestion by earthworms shows that the relative importance of the drilosphere is determined by environmental conditions, soil characteristics, and the quality and amounts of the organic matter inputs (Dominguez, 2004).  The suggestion is made that through colonization of dung earthworms project the drilosphere to the heart of this waste material incorporating from within as well as from the soil beneath .  

Lavelle et al (1998) Earthworms as a resource in tropical agroecosystems,  Nat.Resour., 34:26-41

Dominguez, J. (2004) State-of-the-Art and New Perspectives in Vermicomposting Research, Earthworm Ecology (Ed Clive A. Edwards) 20: 401-417

Is immunity of Scathophaga stercoraria enhanced by use of veterinary pharmaceuticals?

Greig, J.W., Hirsch, P.R. & West, H.M.

School of Biosciences, University of Nottingham

 

Abstract

Potentially toxic but sub-lethal effects of ivermectin on non-target invertebrates have been reported. A recent investigation at Nottingham showed that egg-to-adult exposure to extremely low concentrations of ivermectin elevated phenoloxidase activity in yellow dung flies (Scathophaga stercoraria) developing in cattle dung. We will introduce a new project which aims to quantify immune responses of the yellow dung fly to ivermectin and determine whether a heightened ivermectin-induced immune response enhances survival against microbial challenges and/or whether there is an energetic trade-off between maintaining an up-regulated immune response and reproductive output.

Using organic biomarkers to investigate the interactions between cow slurry and soil hydrological and erosion processes.

Lloyd, C.E.M.¹, Michaelides, K.¹, Evershed, R.P²., Chadwick, D.³ and Dungait, J.A.J.<sup>3

1</sup> School of Geographical Sciences, University of Bristol, ² Organic Geochemistry Unit, Bristol Biogeochemistry Research Centre, University of Bristol, ³ Soil and Water Team, North Wyke Research, Okehampton, Devon

 

Abstract

Every year in the UK, approximately 5 million tonnes of organic carbon (OC) is returned to the soil due to applications of farm manures or slurries. However, very little is known about the composition of this widely used soil-improver at a chemical compound level, and how this material interacts with the soil system.  We have explored the use of different organic geochemistry biomarkers as tracers for components of organic matter from cow slurry using a small-scale laboratory experiment. A 30x30x30 cm soil lysimeter was set up with an application of cow slurry on the surface and rainfall was simulated until the 1-D system reached hydrological equilibrium. Analysis of lysimeter soil cores and the leachates from the base of the soil are used to identify the most suitable biomarkers to trace organic matter which is 1) particulate and bound to soil, 2) free particulates, 3) dissolved. For example, the biomarker compounds, 5β-stigmastanol and 5β-epistigmastanol, are widely used to trace the fate of faecal contamination of soils and water courses (Bull et al., 2002), and their abundance was used to track the movement of the hydrophobic component of the slurry.  These biomarkers can then be used in larger scale laboratory and field experiments to explore these soil-slurry interactions in 3-D environments.

 
Earthworms and their environment: functional processes.

Jennifer A. J. Dungait, Maria J. I. Briones, Liz Dixon, Neil Donovan, Roland Bol, and Richard P. Evershed

North Wyke Research, Okehampton, Devon

 

Abstract

Stable isotope values reflect assimilated, rather than ingested, dietary components and can be used to quantify OM fluxes between earthworms and their environment as functional processes. Using bulk tissue ¹³C/¹⁵N stable isotope analysis and compound-specific fatty acid (FA) stable isotope analyses we have shown that epigeic Lumbricus rubellus and endogeic Allolobophora chlorotica utilising natural abundance ¹³C-labelled dung (d¹³C = -12.6‰) as a dietary resource displayed trophic niche differentiation. Bulk d¹³C/d¹⁵N values demonstrated that all earthworms utilised dung as a resource, and epigeic earthworm tissues were ¹³C- and ¹⁵N-enriched relative to those of endogeic species. Although exhibiting similar FA profiles, individual FA d¹³C values revealed extensive routing of dietary C into body tissue of L. rubellus, but minor incorporation in A. chlorotica.  In particular, the direct incorporation of microbial biomarker FA (iC_17:0, aC_17:0) from ¹³C-labelled dung in situ, the routing of dung C into de novo synthesised compounds (C_20:4w6, C_20:5w3), and assimilation of essential fatty acids (C_18:1w9, C_18:1w7, C_18:2w6, C_18:3w3) derived from dung, was determined. In a subsequent experiment, L. rubellus earthworms were introduced to mesocosms and fed for 30 days with highly ¹³C/¹⁵N-labelled ryegrass (¹³C = 4 at.%; ¹⁵N = 23 at.%) mixed with dung. Stable isotope ratio mass spectrometry was used to determine incorporation of ¹³C and ¹⁵N into earthworm tissues and fresh and incubated casts in order to assess turnover of dietary C and N over time.

 

Predatory activity of the "noon fly"  Mesembrina meridiana

Luke Dickson¹, Richard Evershed² & Richard Wall<sup>1

1</sup>School of Biological Sciences and ²Geochemistry Unit, Bristol Biogeochemistry Research Centre, University of Bristol.

 

Abstract

Mesembrina meridiana (Diptera: Muscidae) larvae have been described variously as facultatively carnivorous and purely coprophagous. In a laboratory microcosm, M. meridiana larvae were offered ¹³C-labelled larval N. cornicina (e.g. δ¹³C(a15:0), 558±13‰(SE)) as potential prey in a matrix of unlabelled cow dung (e.g. δ¹³C(a15:0), ^‑36±1‰(SE)). After feeding in these microcosms, total FAs in the gut contents of M. meridiana larvae were ¹³C-enriched (e.g. δ¹³C(a15:0), 460±33‰(SE)), thereby disclosing the consumption of both unlabelled dung and ¹³C-labelled prey. Using data from the analysis of eight FAs in M. meridiana gut contents and its two foods, the estimated proportion of dung in the binary ingested diet was 65±15% (SE, n = 5). A novel technique using dung containing a rare earth element tracer was used to time the M. meridiana gut transit whilst parameterising the diet choice experiment,