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Effects of avermectin residues in cattle dung on dung beetle (Coleoptera: Scarabaeidae) reproduction and survival
Abstract
Scarabaeine dung beetles feeding on dung from cattle treated with an injection of avermectin at a therapeutic dose to control internal parasites, show larval mortality, mortality of immature adults, reduced egg production, and inhibited ovariole development for periods of 1-4 weeks following treatment. In winter rainfall regions of Australia, feeding by newly emerged adults of an introduced species, Onthophagus binodis, resulted in shredding of cattle dung between December and May. Production of brood masses and eggs resulted in dung being buried from September to November. Feeding by newly emerged adults of a native species, Onthophagus ferox, resulted in dung being buried in May and June, and production of brood masses for breeding resulted in dung burial between September and November. There are thus 2-6 months of the year when injection of cattle with avermectin would affect mortality of newly emerged beetles, and 3 months of the year when avermectin treatment of cattle would affect dung beetle oviposition or larval survival. Beetles were attracted to fresh dung for 2-4 days, and most had left the pad within a week. There are no data to indicate the effects of avermectin residues in dung on dung beetle populations and on beetle fitness. Tests should be done to determine if avermectins in slow release devices have a greater effect on dung beetles than injections, and to determine what effects both have on dung beetle populations.
... It is important to view the Þndings of this study in the context of parasite control programs for cattle in Australia. Ridsdill-Smith (1993) concluded that the recommended time of treatment of cattle by avermectin injection did not coincide with the breeding periods of O. binodis in Western Australia. However, cattle parasite control programs generally recommend that the Þrst summer treatment be given to calves in November, followed by a second treatment in January/February. ...
... As mentioned earlier, newly emerged dung beetles suffer directly from exposure to avermectin residues in cattle dung (adult mortality), whereas mature breeding beetles are affected at sublethal levels (reduced egg production). Newly emerged dung beetle populations are typically at their peak in summer when the beetles actively feed on dung (Ridsdill-Smith 1993). If farmers replace other avermectin formulations with an anthelmintic such as doramectin, which has less impact on dung beetle activity in the spring breeding period, dung beetle populations should be conserved. ...
Feedlotting cattle with dietary supplements of grain before market is becoming a widespread practice in Australia. Many farmers involved in this practice have noticed a minimal amount of dung beetle activity in the dung produced by cattle being fed grain diets. In this study, the dung from both feedlotted (grain-fed) and pasture-fed cattle was assessed as a food and reproductive resource for the dung beetle Onthophagus binodis Thunberg by bioassay in the laboratory. The diet of grain-fed cattle consisted of either 15% lupins, 20% oats, and 65% barley (50% grain) (grain 1) or 70% lupin grain and 30% hay (grain 2). There was no significant difference in either adult beetle mortality or the emergence pattern of F1 progeny when beetles were maintained on dung from either grain-fed or pasture-fed cattle. However, dung beetles reared on dung from pasture-fed cattle produced significantly more brood masses compared with beetles reared on dung from cattle fed on grain 2. A significantly greater number of F1 progeny survived to adulthood from brood masses produced by beetles reared on dung from pasture-fed cattle compared with dung from grain-fed cattle. The progeny emerging from brood masses produced with dung from pasture-fed cattle were significantly larger compared with progeny emerging from brood masses produced with dung from grain-fed cattle.
... It is important to view the Þndings of this study in the context of parasite control programs for cattle in Australia. Ridsdill-Smith (1993) concluded that the recommended time of treatment of cattle by avermectin injection did not coincide with the breeding periods of O. binodis in Western Australia. However, cattle parasite control programs generally recommend that the Þrst summer treatment be given to calves in November, followed by a second treatment in January/February. ...
... As mentioned earlier, newly emerged dung beetles suffer directly from exposure to avermectin residues in cattle dung (adult mortality), whereas mature breeding beetles are affected at sublethal levels (reduced egg production). Newly emerged dung beetle populations are typically at their peak in summer when the beetles actively feed on dung (Ridsdill-Smith 1993). If farmers replace other avermectin formulations with an anthelmintic such as doramectin, which has less impact on dung beetle activity in the spring breeding period, dung beetle populations should be conserved. ...
Two groups of 50 heifers were given a subcutaneous injection of either abamectin (Avomec) or doramectin (Dectomax) at a dose rate of 200 μg/kg live weight. A third group of 50 heifers remained untreated. Dung samples were collected on 1, 3, 6, 9, 18, 24, 34, and 42 d after injection, and excreted residues were bioassayed using the dung beetle Onthophagus binodis Thunberg. Fewer newly emerged adults of O. binodis survived exposure to dung from cattle treated 3 and 6 d previously with abamectin or 9 d previously with doramectin than from dung of untreated cattle. Both compounds induced a range of sublethal effects on O.binodis. Abamectin residues excreted in dung up to 42 d after injection had a deleterious impact on ovarian condition, brood mass (egg) production, and larval survival. Doramectin residues only had a deleterious effect on these parameters at 3 and 6 d after injection relative to dung from control cattle. Analysis of the dung collected at each date after injection indicated that moisture content, pH, and percent nitrogen were not different from other physicochemical profiles conducted on cattle dung. Doramectin residues attained maximal concentrations of 101.1 μg/kg 3 d after injection followed by a linear decline with an elimination half-life estimate of 15 d. The bioassay data indicated that doramectin concentrations of <60 μg/kg have minimal impact on the mortality and reproductive potential of O. binodis and that deleterious effects to this species will be evident for only 1-2 wk after administration of the drug to cattle. The potential ecotoxic effects of these compounds are discussed in terms of dung beetle activity and strategies for parasite control of cattle in the Australian environment.
... The issue of avermectins and their environmental effects is a controversial area (McCracken, 1993;Ridsdill-Smith, 1993;Herd, 1995Herd, , 1996Forbes, 1996;Wardhaugh & Ridsdill-Smith, 1998). The treatment of terrestrial animals for parasite control is seasonal, as is the breeding of dung fauna. ...
... The treatment of terrestrial animals for parasite control is seasonal, as is the breeding of dung fauna. The latter might be at less risk if the breeding season and the treatment seasons are separate, but there may be some degree of risk if coincidental, and the concentrations found may depend on a number of factors including the diets of the treated animals (Ridsdill-Smith, 1993;Cook et al., 1996;McKellar, 1997;Lumaret & Errouissi, 2002), and not all cattle in a herd will necessarily be treated simultaneously (Roncalli, 1989). Interestingly, the original environmental impact assessments of avermectins in the United States took into account patterns of use, their toxicity, metabolic characteristics, predicted environmental concentrations and behaviour in the environment but no consideration was given to effects on dung pat degradation or dung fauna (Bloom & Matheson, 1993). ...
Like humans, animals may experience adverse effects when treated with medicinal products. These effects may be related to the pharmacological or toxicological properties of the substances used or they may arise because of hypersensitivity. Veterinary medicinal products may also possess the ability to harm the environment. This paper reviews the potential of veterinary medicinal products to cause adverse effects in animals and on the environment.
... They promote the decomposition of dung [28] in close interaction with microorganisms and other fauna like nematodes and oligochaetes, playing a vital role in maintaining pasture hygiene, nutrient cycling , soil aeration, water percolation, humus content and pasture productivity. The issue of antiparasitics (and/or their metabolites ) and their environmental effects are a controversial area [7, 17, 21, 24, 30], and the responsible authorities in the European Union (as well as in North America and Japan) require data on the effects of new veterinary antiparasiticals on dung organisms as part of the environmental risk assessment (see Phase II, Part A of the VICH Guidance Paper) [4,29]. Usually these data are obtained from laboratory tests (depending on their results semi-field studies are required), but up to now no standardized test guidelines are available. ...
... The next step in the development of this test is the formal standardization by OECD, for example as a test guideline or as a guidance document. According to the current legal situation (VICH 2005) [24] , the test – together with a dung fly test [23] – is required for all antiparasitic pharmaceuticals which are used to treat pasture animals (Tier A, Chapter 3.1.3.2). According to the VICH guideline as well as to the recently published Technical Guidance Document [4] further tests are necessary if an environmental risk is identified in the dung beetle test. ...
According to European Union recommendations, a test method has been developed to evaluate the effects of veterinary pharmaceuticals on dung feeding insects. This test method was evaluated with the dung beetle Aphodius constans by using fecal residues of ivermectin after a pour-on administration. Dung of different age (and thus containing different concentrations of ivermectin) as well as mixtures of highly-contaminated spiked dung with untreated control dung were studied in five test runs in two laboratories. The concentration of ivermectin (active substance; a.s.) in the dung samples was verified analytically. The main test endpoint was the survival of first instar larvae. The LC50 using dung directly obtained from treated cattle ranged from 470 to 692 microg a.s. kg(-1) dung (dry weight; d.w.) and 67 to 97 microg a.s. kg(-1) dung (fresh weight; f.w.). Using mixtures, the outcome of two tests was almost identical: 770 to 781 microg a.s. kg(-1) dung (d.w.); 109 to 132 microg a.s. kg(-1) dung (f.w.). In comparison to the LC50 values obtained when ivermectin was spiked in control dung at several concentrations (LC50 880-985 microg a.s. kg(-1) dung (d.w.)), the LC50 values were again very similar. Three conclusions can be drawn from these results. The proposed test method seems to be robust and allows for the initiation of an international validation process (including ringtesting). Because of only small differences found in tests in which the test substance was spiked into control dung and those in which dung from treated cattle was applied, the use of a standard test method is proposed. The effects of ivermectin on ecologically relevant dung beetles obtained in a standardised test method reflect the results from field studies and are in the range of environmentally relevant concentrations.
... Dung beetles already face indirect challenges in temperate grasslands due to changes in livestock management practices: including more intensive feeding regimes, and changes in patterns of endoparasitic chemicals administered to livestock, e.g., mectins are greatly more toxic than benzimidazole to dung beetles. Ivermectin and abamectin cause a reduction in successful emergence and hatching of dung beetle larva (Ridsdill-Smith 1993c, Wardhaugh et al. 1993, Floate 1998, Dadour et al. 1999, Wardhaugh et al. 2001, Wardhaugh 2005, Beynon et al. 2012, Beynon 2012. To understand if dung beetles can continue to provide ecosystem services across temperate Australia under changing management and climate, we review what is known about their life history traits that will facilitate their adaption. ...
Both indigenous and introduced Australian dung beetles (Coleoptera: Scarabaeoidea) play an important role in agricultural systems. Temperate grasslands in Australia are expected to have some of the greatest increases in temperature and reduction in precipitation due to climate change which may directly threaten dung beetles. Several biotic and abiotic factors affect the development of larvae and fitness of young dung beetles. To understand if dung beetles can continue to provide ecosystem services across temperate Australia under changing management and climate, we review what is known about their life history traits that will facilitate their adaption.
We believe dung beetles will continue to provide valuable ecosystem services and have potential to aid in adapting and alleviating the impacts on crops and pastures from reduced and sporadic rainfall. However, the level of function, may be impeded due to climatic stress and a loss of diversity with thermal specialists and some indigenous species, expected to be displaced into narrower ranges. An increase in feeding competition from thermal generalists and introduced species will likely implement this movement. The evidence from naturalised introduced species indicate behavioural adaptations and/or phenotypic plasticity suggest some species will continuing to provide services that improve pasture production despite changes to climate. Ongoing monitoring of phenological shifts will inform adaptive management of this vital group.
... In the UK and northern Europe resistance is also on the rise, but complete resistance has yet to occur (Taylor et al. 2009;Traversa and von Samson-Himmelstjerna 2016). Climate change and global trade have also increased helmintic infections in livestock by increasing the abundance of specific zoonotic parasites (or their hosts), and by introducing new parasites into new regions (Fayer 2000;Fox et al. example, lab and field studies suggest anthelmintic residues in livestock dung reduce beetle populations by decreasing egg production and increasing larval mortality (Cook et al. 2017;Numa et al. 2012;Ridsdill-Smith 1993). International and national initiatives support the development of new preventative or therapeutic alternatives 1 , but current research continues to focus on developing chemical solutions that deactivate specific genes or proteins in parasites that disrupt ability to feed, nicotinic acetylcholine receptors (nAChR), and fertility (Hotez et al. 2010;Kaminsky et al. 2008;Sabatelli 2010). ...
p class="Abstract">Anthelmintic resistance in livestock is increasing globally. Livestock intestinal parasites now develop resistance to synthetic anthelmintics within 2–10 years, collectively costing billions of dollars annually in lost revenue around the world. Over-reliance on commercial drugs and dips and changes in livestock management practices are key drivers of this trend. To date, current research has focused on identifying new anthelmintics from bacterial and fungal sources or even synthesizing new drugs that target parasite metabolism or reproduction. Plant-derived anthelmintics are a promising alternative, yet to date major research funders and scientists have overlooked this option. Until the mid-20<sup>th</sup> century, rural communities relied on plant-based methods of controlling livestock parasites. These methods include feeding livestock specific medicinal plants and trees, grazing livestock on herbal leys, and changing where livestock grazed based on ecological factors (e.g., flooding) that increased parasite burdens. Many historic texts and ethnological accounts record the ethnobotanical knowledge of rural communities and the plants they used to control livestock intestinal parasites. Some traditions persist today yet the farmers, graziers, and shepherds who hold this knowledge are rapidly disappearing and with them perhaps a potential long-term solution to anthelmintic resistance. This short perspective piece will cover recent research using ethnobotanical data as a means to identifying potential new anthelmintics; the morphological, physiological, and metabolic effect of plant secondary metabolites on parasites; and an overview of “best practices” which can reduce bias in assessments of plant bioactivity and increase reproducibility of test results. This will hopefully bring recent advances in ethnobiology, chemistry, and ecology to new audiences, and, potentially, spark new interest in using medicinal plants to improve livestock health.</p
... The reduced numbers of eggs in pats from ivermectin-treated animals would suggest that colonizing females laid fewer eggs in these pats than in control dung, even if they were more attracted by treated dung (Strong et al., 1996). This finding can be explained by the fact that ivermectin could induce reproductive deficiencies in dung beetles (Wardhaugh & Rodriguez-Menendez, 1988;Ridsdill-Smith, 1993;Wardhaugh et al., 1993). Wardhaugh et al. (1993) also noted that adults of Euoniticellus fulvus Goeze (Coleoptera: Scarabaeidae) failed to feed normally after ingesting dung from sheep drenched with ivermectin 1 day previously. ...
... Adult beetles were collected from a dairy farm in southwest Western Australia in early and mid-October, when adults are most actively burying dung and producing brood masses in the field (Ridsdill-Smith, 1993). Approximately 60 females were established in individual breeding chambers (PVC piping, 25 cm in length and 6 cm in diameter) filled three-quarters with moist sand and topped with 100 g cow dung. ...
When females mate with multiple males, they set the stage for post-copulatory sexual selection via sperm competition and/or cryptic female choice. Surprisingly little is known about the rates of multiple mating by females in the wild, despite the importance of this information in understanding the potential for post-copulatory sexual selection to drive the evolution of reproductive behavior, morphology, and physiology. Dung beetles in the genus Onthophagus have become a laboratory model for studying pre- and post-copulatory sexual selection, yet we still lack information about the reproductive behavior of female dung beetles in natural populations. Here, we develop microsatellite markers for Onthophagus taurus, and use them to genotype the offspring of wild-caught females, and to estimate natural rates of multiple mating and patterns of sperm utilization. We found that O. taurus females are highly polyandrous: 88% of females produced clutches sired by at least two males, and 5% produced clutches with as many as five sires. Several females (23%) produced clutches with significant paternity skew, indicating the potential for strong post-copulatory sexual selection in natural populations. There were also strong positive correlations between the number of offspring produced and both number of fathers and paternity skew, which suggests that females benefit from mating polyandrously by inciting post-copulatory mechanisms that bias paternity towards males that can sire more viable offspring. This study evaluates the fitness consequences of polyandry for an insect in the wild, and provides strong evidence that female dung beetles benefit from multiple mating under natural conditions. This article is protected by copyright. All rights reserved.
... Fresh dung was collected on site from animals that had not been treated with anthelmintics in at least the preceding 6 weeks. Drug-free dung was preferred as anthelmintics have been proven to alter the attractiveness of dung and to have a negative impact on dung beetles (Wardhaugh and Mahon 1991;Ridsdill-Smith 1993;Holter et al. 1993). Once collected, the dung was homogenized and divided into standard amounts of 300 g for cattle dung and 200 g for horse and sheep dung and frozen at −20 °C for at least 2 days (as in, e.g., Slade et al. 2007) to kill all groups of biota that consume a considerable part of dung (e.g., dung beetles, earthworms, fly larvae,…) or interfere with the experiment in a different way (e.g., predatory beetles hunting for fly or dung beetle larvae). ...
Dung beetles form an insect group that fulfils important functions in terrestrial ecosystems throughout the world. These include nutrient cycling through dung removal, soil bioturbation, plant growth, secondary seed dispersal and parasite control. We conducted field experiments at two sites in the northern hemisphere temperate region in which dung removal and secondary seed dispersal were assessed. Dung beetles were classified in three functional groups, depending on their size and dung manipulation method: dwellers, large and small tunnelers. Other soil inhabiting fauna were included as a fourth functional group. Dung removal and seed dispersal by each individual functional group and combinations thereof were estimated in exclusion experiments using different dung types. Dwellers were the most diverse and abundant group, but tunnelers were dominant in terms of biomass. All dung beetle functional groups had a clear preference for fresh dung. The ecosystem services in dung removal and secondary seed dispersal provided by dung beetles were significant and differed between functional groups. Although in absolute numbers more dwellers were found, large tunnelers were disproportionally important for dung burial and seed removal. In the absence of dung beetles, other soil inhabiting fauna, such as earthworms, partly took over the dung decomposing role of dung beetles while most dung was processed when all native functional groups were present. Our results, therefore, emphasize the need to conserve functionally complete dung ecosystems to maintain full ecosystem functioning.
... De plus, la présence de ces organismes est un bon indicateur de l'activité et de l'état de santé d'un milieu. Ce rôle en tant que maillon élémentaire de la chaîne trophique a par exemple été mis en évidence lors d'études sur l'avermectine, un traitement anti-parasitaire fréquemment employé dans les élevages bovins (Halley et al. 1993, Ridsdill-Smith 1993, Strong 1993, Wardhaugh et al. 1993, Iglesias et al. 2006. Ces analyses ont mis en évidence un double effet du traitement sur les populations de vers (lombrics et nématodes) et d'insectes coprophages, et sur la vitesse de dégradation des excréments. ...
When a cadaver is discovered, investigators need to determine precisely the date and time of death. This information is provided by forensic examiners through the study of cadaver characteristics and decomposition state. However, these techniques are effective only during few days after the death. After this delay, the post-mortem interval (PMI) estimation based on these parameters becomes difficult and imprecise. In this case, is it possible to use forensic entomology, the analysis of necrophagous insects sampled on the cadaver to estimate the time of the death. The main goal is to date the first eggs layed on the cadaver by calculating the age of sampled insects.
The first aim of the present study is to improve the knowledge about the behaviour and the development of necrophagous dipterans. Experiments performed cover the seasonal trend in necrophagous insect populations, variations in the intrinsic speed of development of larvae, their displacement speed, the structure and behaviour of maggot masses, and the thermal behaviour of corpses. For each of these points, a detailed literature review was conducted. Material, methods and the results are detailed and analyzed, and replaced in the forensic entomology application field.
The data and observations obtained during this research have also formed the basis for a computer based development model, which simulates the development and behaviour of dipterans necrophagous larvae on a body. In addition to its explanatory function, this simulation tool is the first level of a huge reasoning system. Designed to achieve expertise in forensic entomology, this program can estimate the moment of death from the comparison between simulations results and specimens sampled on a body.
Thus, this thesis focuses on a dual goal: increase the knowledge on the biology of necrophageous insects, and improve the accuracy and reliability of entomological expertises through the development of computer analysis
... Also, Avermectin used for controlling internal parasites in cattle has resulted in high residues in dung, which adversely impacted beetles important to dung breakdown and cycling [46]. Because of the potential for adverse effects to non-target organisms, environmental fate studies and assessments are required for pharmaceutical actives released to the environment in order to determine whether exposures may be sufficient to manifest harm [47]. ...
Plant-made pharmaceuticals (PMPs) offer great promise as efficacious and cost-effective products for the treatment of human and animal disease. The benefits of this technology must be balanced against potential health and environmental risks that may be associated with its use. Risks associated with human and animal health and environmental impacts of PMPs can be minimized through adoption of production confinement and product channelling processes that have stringencies consistent with the degree of hazard or uncertainty associated with a specific product. Risk assessment considers the probability for harm to occur as a consequence of exposure in the production, processing, and use of a given PMP. Risk assessment focused on the intended uses of PMPs involves manufacturing and medicinal use scenarios that consider workers and consumers of the PMP; whereas the risk assessment for unintended occurrence in food or feeds considers a differing nature of exposure (in terms of the route, intensity, frequency and duration of exposure). The consequences of intended and unintended use both must be considered and managed for comprehensive understanding of risk. Regardless, because PMPs presently have no provision for regulatory tolerances, their inadvertent occurrence in foods or feeds remains an important economic consideration, even when the health and environmental risks are low. Various production options may be utilized to account for uncertainties in order to mitigate the risks of PMPs.
... Concern has been raised about potential adverse effects on dung beetles, which contribute to soil fertility and sustainability of pastoral ecosystems (Wall and Strong, 1987;Strong, 1993;Beckmann, 1996,1997;McKellar, 1997). Laboratory injections of avermectin/ ivermectin to heifers negatively affected larval dung beetles including Diastellopalpus quinquedens and Onthophagus gazella (Sommer et al., 1993;Sommer and Overgaard Nielsen, 1992), O. binodis (Roncalli, 1989), O. ferox (Ridsdill-Smith, 1993), Euoniticellus intermedius (Fincher, 1992) and Onitis alexis (Krüger and Scholtz, 1997). Field studies in South Africa detected reduced species diversity and increased species dominance in dung beetle communities after ivermectin treatment of cattle under drought, but not under high-rainfall conditions (Krüger and Scholtz, 1998a,b). ...
A long-term and large-scale field study was carried out to assess the ecotoxicological effect on the dung beetle fauna of cattle treatment with ivermectin (broad-spectrum endectocide) and fluazuron (acaricide) under normal extensive farming conditions in South Africa. One herd of 25 heifers was treated four times at an 8-week interval (starting late November 2001) with a standard injection of ivermectin (200 μg/kg) and a standard pour-on dosage of fluazuron (3 mg/kg) and another herd was left untreated as a control. This set-up was replicated on a second, separate farm and the four herds were kept in four separate paddocks of about 80 ha each. Dung beetle communities were monitored over an entire farming season, from early November 2001 until August 2002. This study was carried out in a very moist year with above average rainfall. The impact of the treatment on the dung beetle communities was examined using a variety of community measures as well as a wide range of univariate, graphical and multivariate analyses. There was no observable effect of the administered drugs on the dung beetle communities. Species richness and diversity seemed unaffected in the treated communities and the ecological similarity of the treated and control communities remained high through most of the trial. These results support the notion that the ecotoxicological impact of antiparasitic drugs depends on factors such as climatic conditions, spatial scale of treatment and proportion of animals treated.
... The reduced numbers of eggs in pats from ivermectin-treated animals would suggest that colonizing females laid fewer eggs in these pats than in control dung, even if they were more attracted by treated dung (Strong et al., 1996). This finding can be explained by the fact that ivermectin could induce reproductive deficiencies in dung beetles (Wardhaugh & Rodriguez-Menendez, 1988;Ridsdill-Smith, 1993;Wardhaugh et al., 1993). Wardhaugh et al. (1993) also noted that adults of Euoniticellus fulvus Goeze (Coleoptera: Scarabaeidae) failed to feed normally after ingesting dung from sheep drenched with ivermectin 1 day previously. ...
A 2-year study was performed in two sites in southern France to assess the effect of ivermectin residues on the attractiveness of cattle dung to colonizing insects. Insect captures were compared between pitfall traps baited with dung from untreated cattle and dung from cattle that had been treated with a slow-release (SR) bolus of ivermectin. Cattle dung was collected at different times after treatment (4, 14, 42, 70 and 98 days). Excretion showed a plateau, with levels ranging between 0.688 µg and 1.123 µg ivermectin per gram of wet dung. Faecal residues affected insect captures at both sites. Effects were independent of the time dung was collected after treatment, except for one result subsequent to a severe drought during the baiting period. Ivermectin-contaminated dung showed a significant attractive effect, with increased captures regardless of the guild to which beetles belonged. This study demonstrates the attractiveness of ivermectin residues over a long period after the treatment of animals. It draws attention to the danger of widespread use of this endectocide-based SR bolus, which is attributable to the preferential attraction of insects to treated dung, which potentially puts at risk the survival of their offspring.
... The reduced numbers of eggs in the pats from ivermectin-treated animals suggests that colonising females laid fewer eggs than in dung from the other two treatment groups. This finding is readily explained by the fact that ivermectin-induced reproductive deficiencies in dung beetles have been documented previously (Wardhaugh and Rodriguez-Menendez, 1988;Ridsdill-Smith, 1993;Wardhaugh et al., 1993). Wardhaugh and Rodriguez-Menendez (1988) also observed mortality in some adult beetles after contacting the dung of cattle injected with ivermectin. ...
The effects of faecal drug residues following the administration of anthelmintics in the form of sustained-release boluses, on dung-colonising Coleoptera and Diptera are reported. In blind field trials, pats of standard weight and size were prepared from the dung of cattle treated with an ivermectin (Ivomec SR Bolus, MSD Agvet) or a fenbendazole (Panacur Bolus, Hoechst) sustained-release bolus, and from a third control group of cattle that received no treatment. Pats were recovered after 7, 14, 21 and 42 days in the field and searched for invertebrates. There were no differences in the numbers of adult beetles found in the pats from the three treatment groups. Pats made from the dung of ivermectin-treated animals contained no larval Diptera Cyclorrhapha and significantly fewer larval Scarabaeidae than pats made from the dung of the other two groups. Furthermore, larval Scarabaeidae in the ivermectin pats were inhibited in their development. The pats from fenbendazole-treated animals contained similar numbers of larval Scarabaeidae and Diptera to the pats from untreated animals throughout the trial. At 42 days, the solid matter of the control and fenbendazole-containing cow pats were reduced to a crumbling, granular texture, while the pats from the ivermectin-treated animals were solid and compacted. Pitfall trapping, using traps baited with dung from the three groups, showed no significant difference between the numbers of adult Scarabaeidae attracted, though a trend towards higher numbers attracted to the dung of both anthelmintic-treated groups was evident. The results provide evidence of the toxic effects of excreted ivermectin on key dung-colonising families of insects, and show that fenbendazole lacks such toxic effects.
... However this does not discount the possibility of sublethal effects due to short-term exposure of ivermectin residues[22]. During the warmer months of the year, beetles move from pat to pat every two to four days, particularly when they are abundant and/or immature[87]. Thus in situations in which the whole herd may be treated, the chance that beetles will contact toxic faeces will be very high. ...
The overall purpose ofthis paperwas to review the major and most recent literature relating the effects of anthelmintics on dung breeding invertebrates and dung degradation. Faecal residues or metabolites of drugs belonging to the benzimidazole and levamisole/morantel groups are relatively harmless to dung fauna, on the contrary to other anthelmintics such as coumaphos, dichlorvos, phenothiazine, piperazine, synthetic pyrethroids, and most macrocyclic lactones which have been shown to be highly toxic for dung beetles (abamectin, ivermectin, eprinomectin, doramectin), among which moxidectin was the less toxic for dung beetles. To date, the detrimental impact upon non-target organisms has been considered acceptable in eradicating the parasites because of their economic importance to commercial livestock production. The consequences of routine treatments are discussed with consideration of the long-term consequences for cow pat fauna and sustainable pastureland ecology.
... Release of veterinary medicines to the environment occurs both directly, for example the use of medicines in fish farms, and indirectly, via the application of animal manure (containing excreted products) to land. A number of groups of veterinary medicines, primarily sheep dip chemicals (Environment Agency, 1998, 2000 SEPA, 2000), fish farm medicines (Davies et al., 1998; Jacobsen and Berglind, 1988) and anthelmintics (McKellar, 1997; Strong, 1993; McCracken, 1993; Madsen et al., 1990; Ridsill-Smith, 1988; Wall and Strong, 1987) have been extensively studied and a large body of data is available for these substances. Information is also available on selected antibiotics (e.g. ...
A wide range of veterinary medicines is used to treat animals in the UK. Whilst the environmental impact of selected substances (particulary the sheep dip chemicals, anthelmintics and fish farm chemicals) has been well studied, limited information is available in the public domain on the other groups of substances (e.g. antifungals, coccidiostats, antiprotozoals, hormones and growth promoters). There is therefore a need to identify other substances that may impact the environment in order to design national monitoring programmes, target experimental work and develop pollution prevention methodologies. In this study, a simple two-stage prioritisation scheme was developed and applied to veterinary medicines in use in the UK. In the first stage, those substances that have high potential to enter the environment in significant amounts were identified on the basis of amounts used in the UK, treatment type and metabolism. In stage 2, the hazard of the identified substances to terrestrial and aquatic organisms was assessed. Using the approach, a total of 56 substances or groups were assigned to a 'high priority' category. For eleven of these substances, sufficient data were available to characterise their risk, these were: oxytetracycline, chlortetracycline, tetracycline, sulphadiazine, amoxicillin, diazinon, tylosin, dihydrostreptomycin, apramycin, cypermethrin and sarafloxicin. For the remaining 45 substances, full datasets were not available and it is recommended that in the first instance, attempts are made to fill these data gaps.
... Avermectins are highly insoluble in water and have a strong tendency to bind to particles. Residues of avermectin drugs or their metabolites in faeces of livestock have adverse effects on some dung-dwelling organisms and non-target invertebrates living in soil (Cook, 1993; Halley et al., 1993; Holter et al., 1993; King, 1993; Mahon et al., 1993; Moore et al., 1993; Ridsdill-Smith, 1993; Strong and James, 1993; Wardhaugh et al., 1993; Lumaret and Errouissi, 2002; Steel and Wardhaugh, 2002; Suarez, 2002 ). The disturbances that macrocyclic lactones can produce on non-targeted invertebrates, and on their associated participation in dung degradation and soil element recycling, are unpredictable and can negatively influence biodiversity and agricultural ecosystem sustainability . ...
We studied abamectin and doramectin excretion and their degradation in sheep faeces under field conditions on pasture after a single subcutaneous dose (0.2mg/kg body weight). In the excretion experiment, maximal abamectin concentration (1277 ng/g dry faeces) was detected on day 3, while doramectin concentration showed two peaks (2186 and 1780 ng/g dry faeces on days 2 and 5, respectively). Both avermectins were excreted at approximately the same rate (k=0.23 day(-1) for abamectin and 0.19 day(-1) for doramectin). In the field, a rapid loss of abamectin and doramectin from sheep faeces was seen during the first 32 days after which concentrations remained constant at approximately 77 ng/g and 300 ng/g, respectively. The half life values (DT(50)) for abamectin and doramectin dissipation from sheep faeces were 23 and 22 days, respectively, during the first 32 days. Dissipation of both avermectins was strongly correlated with moisture content of the faeces.
... Many tests have been conducted on the toxicity of the widely used avermectins (e.g. Wardhaugh & Rodriguez-Menendez, 1988;McCracken & Foster, 1993;Ridsdill-Smith et al., 1993;Sommer et al., 1993;Strong et al., 1993Strong et al., , 1996Strong & Wall, 1994;Krü ger & Scholtz, 1997, 1998a, 1998bFloate, 1998;Dadour et al., 1999;reviewed in Floate et al., 2005). In contrast, only few studies (Bianchin et al., 1998;Krü ger et al., 1998Krü ger et al., , 1999 have investigated the relative toxicity of pyrethroids against beneficial dung fauna, despite the fact that pyrethroids are used extensively for control of ectoparasites on farm livestock (Srivastava et al., 1993;Franc & Cadiergues, 1994;Kok et al., 1996). ...
In a bioassay to determine non-target ecotoxicological effects of a pyrethroid spray (Ektoban) on dung beetles, dung from both cypermethrin/cymiazol-treated and control cattle was collected one, two, three, five, seven, 14, 21 and 28 days after treatment and fed to a treatment and control group (respectively) of beetles of the species Euoniticellus intermedius (Reiche). This was done to assess whether a spray formulation of cypermethrin may affect dung beetles differently than previously tested pour-on formulations. Following three beetle generations for two weeks each, the experiment retrieved no significant differences in adult or larval survival, egg production, fecundity and fertility between the control and treatment group. These results demonstrated that the used spray formulation of cypermethrin is likely to be far less detrimental to dung beetles than previously tested pour-ons.
... Residues of avermectin drugs or their metabolites in faeces of livestock may have adverse effects on dung-dwelling organisms (Cook, 1993;Halley et al., 1993;Holter et al., 1993;King, 1993;Mahon et al., 1993;Moore et al., 1993;Ridsdill-Smith, 1993;Strong and James, 1993;Wardhaugh et al., 1993;Lumaret and Errouissi, 2002;Steel and Wardhaugh, 2002;Suarez, 2002). Most of these studies determined effects on flies and beetles or their larvae invading freshly deposited faeces in the field, but no dose-response relationships are available except for earthworms (Halley et al., 1989;Gunn and Sadd, 1994;Sun et al., 2005). ...
This study aimed at determining the toxicity of avermectins to soil invertebrates in soil and in faeces from recently treated sheep. Abamectin was more toxic than doramectin. In soil, earthworms (Eisenia andrei) were most affected with LC50s of 18 and 228 mg/kg dry soil, respectively, while LC50s were 67-111 and >300 mg/kg for springtails (Folsomia candida), isopods (Porcellio scaber) and enchytraeids (Enchytraeus crypticus). EC50s for the effect on reproduction of springtails and enchytraeids were 13 and 38 mg/kg, respectively for abamectin, and 42 and 170 mg/kg for doramectin. For earthworms, NOEC was 10 and 8.4 mg/kg for abamectin and doramectin effects on body weight. When exposed in faeces, springtails and enchytraeids gave LC50s and EC50s of 1.0-1.4 and 0.94-1.1 mg/kg dry faeces for abamectin and 2.2->2.4 mg/kg for doramectin. Earthworm reproduction was not affected. This study indicates a potential risk of avermectins for soil invertebrates colonizing faeces from recently treated sheep.
In a bioassay to determine non-target ecotoxicological effects of a pyrethroid spray (Ektoban®) on dung beetles, dung from both cypermethrin/cymiazol-treated and control cattle was collected one, two, three, five, seven, 14, 21 and 28 days after treatment and fed to a treatment and control group (respectively) of beetles of the species Euoniticellus intermedius (Reiche). This was done to assess whether a spray formulation of cypermethrin may affect dung beetles differently than previously tested pour-on formulations. Following three beetle generations for two weeks each, the experiment retrieved no significant differences in adult or larval survival, egg production, fecundity and fertility between the control and treatment group. These results demonstrated that the used spray formulation of cypermethrin is likely to be far less detrimental to dung beetles than previously tested pour-ons.
Toxicological Effects of Veterinary Medicinal Products in Humans is the first definitive guide to discuss the adverse effects of veterinary medicinal products in humans. The chapters focus on occupational safety and consumer issues and examine the circumstances under which exposure is likely to occur. To be in context, it reviews this against the background of adverse health effects from other sources in the veterinary and farming professions. The book examines adverse drug effects reported to regulatory agencies (mainly the FDAÆs Center for Veterinary Medicine) and then considers a series of individual drugs, including antibiotics, anaesthetics and organophosphorus compounds. The chapters also discuss the fundamental aspects of regulatory issues relating to safety assessment, and examine the manner in which user safety is assessed prior to authorisation/approval and what measures can be taken after authorisation/approval in the light of findings from pharmacovigilance activities. There is growing concern over the issue of antimicrobial resistance and the contribution made by veterinary medicinal products. This too is addressed along with the significance to human health and measures that can be taken to mitigate the effects (if any) of the use of antibiotics in animals e.g. prudent use measures. The book will be an essential resource for medical practitioners in hospitals and general practice, pharmaceutical industry scientists, analysts, regulators and risk managers.
Game and biodiversity: Beetle assemblages in game and cattle dung
The relevance of game for the diversity of dung-inhabiting beetles was investigated in Schleswig-Holstein (Northern Germany) in the year 2010. Dung of wild boar (Sus scrofa), red deer (Cervus elaphus), roe deer (Capreolus capreolus), and fallow deer (Dama dama) was used for the investigation and compared to the dung of domestic animals, namely cattle and sheep. The dung-inhabiting beetles were recorded in three types of habitats: wood, bog, and sandy fallow. We also investigated the influence of the prophylactical anti-parasitic treatment in deer parks on the beetle fauna and the natural distribution of dung in the three habitats. The highest frequency of dung pats was recorded in woods and in areas with high and dense vegetation. No significant preference of individual beetle species for a specific type of dung was found; however, the abundances of beetles in (wild and park) game dung were usually higher than in cattle dung. An influence of the pro-phylactical anti-parasitic treatment on beetle species could not be proven unequivocally, because significant differences were not found in all dung types and species. The beetle assemblages of the investigated biotope types were found to be significantly different.
The endectocides (avermectins and milbemycins) comprise a group of highly efficacious, broad-spectrum parasiticides, widely used throughout the world for the control of livestock parasites. Endectocides are excreted mainly in faeces, and to a large extent as unaltered drug. Because of this, these drugs have the capacity to exert adverse effects on insect populations associated with animal dung. Fears have been expressed that this reduction in fauna could have an adverse effect and potentially delay dung degradation, leading to fouling of pastures. Two experiments with treated cattle and sheep were designed to compare the effects of moxidectin and ivermectin on the ny Neomyia cornicina F. (Diptera) and the dung beetles Aphodius haemorrhoidalis (L.) and A. constans Duft. (Col. : Aphodiidae). Larvae of Aphodiidae species and flies were bred in dung collected daily from day 0 to day D+38 post-treatment and the rate of emergence of adults was calculated. In the cattle experiment, no significant differences were observed in the emergence of A. haemorrhoidalis fed with dung from controls or cattle treated with moxidectin (Cydectine(R)1% injectable solution; 0.2 mg per kg body weight) or ivermectin (Ivomec(R) 1% injectable solution; 0.2 mg per kg b.w.). For flies, the rate of emergence of N. cornzicina with moxidectin was significantly lower than control until D+10 post-treatment, not different from control after D+16. The mortality was absolute (100%) until D+20 with ivermectin and the rate of emergence remained lower than control up to D+34. In the sheep experiment, a significant difference in A. constans rates emergence was observed between control and moxidectin for the first 2 days following treatment (Cydectin(R) 0.1% oral drench, 0.2 mg moxidectin per kg b.w.). In the ivermectin group (Oramec(R) 0,088% oral drench at 0.2 mg ivermectin per kg b.w.), the differences with control were significant for 6 days post-treatment. Moxidectin was shown to be safe for N. cornicina development after 3 days post-treatment. In the ivermectin group, differences with control for N. cornicina were significant for 6 days, with null emergence for 5 days post-treatment.
As integral members of pasture ecosystems in warmer climates, scarabaeine dung beetles are useful indicators both of high biodiversity in untransformed pastoral regions and of healthy pastures in untransformed or intensively farmed areas. We outline the use of dung beetles (Coleoptera: Scarabaeidae: Scarabaeinae) variously as biodiversity, ecological or environmental indicators at each of three spatial scales: regional, local, and pasture. At a regional scale, analyses of species distribution are useful both for determining regional boundaries, thus defining limits within which local comparisons are valid, and for defining group distribution centres, which facilitates comparison of biogeographical group compositions of local faunas. At a local scale, characteristic differences in species assemblage structure between natural and transformed habitats are useful both for conservation issues and for certification and marketing of high quality meat produced on natural pastures. At a pasture scale, species responses or assemblage structure may differ between dung containing residues and that lacking residues of avermectin or synthetic pyrethroid livestock pesticides. Thus, dung beetles are useful both for bioassaying the relative toxicity of old and newly developed veterinary products, and for developing more environmentally benign pest control practices. For each of the three spatial scales, we discuss goals, provide mini-reviews of pertinent results, and discuss further research.
The environmental risks of pharmaceuticals have been studied less frequently in comparison to other chemicals such as pesticides and biocides. Nevertheless, during the last few years, veterinary and human medicinal products gained increasingly more attention. Medicinal products for use in veterinary medicine include various groups of chemicals, used for a wide range of purposes for companion and farm animals. The parasiticides and antibiotics are two of the most important groups and as such used fairly often in animal treatment. There are different entry routes of veterinary drugs into the environment. Manure of treated farm animals may contain sig- nificant amounts of the active ingredients or metabolites. They can be excreted from treated animals in agricultural soils directly (pasture) or with the application of manure as a fertiliser. The aquatic environment can also be one of exposure compartments. In this review we will focus on certain veterinary parasiticides and give a few examples how they can be excreted into envi- ronment and what is their environmental persistency and toxicity to some aquatic and terrestrial organisms.
Four studies were conducted on dung beetles (Coleoptera: Scarabaeidae), which are insects of great ecological and economic importance. Range management practices were found to impact dung beetle diversity and abundance. While sampling on organic and conventionally managed ranches in Nebraska, 93% (5,767) of total dung beetle capture was from the organically managed ranch. Only 480 dung beetles (7% of total) were collected from the conventionally managed ranch. Results indicated that organic ranching had increased numbers and diversity of dung beetles.
Comparison of the attractiveness of native and exotic herbivore, carnivore, and omnivore dung yielded 9,089 dung beetles from 15 species. Significant differences were observed in mean dung beetle capture and individual species preference among the dung of omnivores, herbivores, and carnivores. Omnivore dung and carrion were most attractive; however, preference for a specific dung type was not correlated with dung quality or mammalian diet.
Dung beetles are exposed to hypoxic conditions throughout much of their life cycle. Data on hypoxia tolerance of five species of adult dung beetle (Aphodius haemorrhoidalis, Canthon pilularius, Melanocanthon nigricornis, Onthophagus hecate, and Phanaeus vindex) yielded no differences in mean survival time (LT50) among behavioral groups, which ranged from 7-37 hours.
Digitonthophagus gazella (F.) has been intentionally released in numerous areas around the world. Using amplified fragment length polymorphism (AFLP) analysis, genetic variation was examined between two populations of D. gazella from South Africa and Vieques, Puerto Rico. Analysis of molecular variance (AMOVA) revealed 69% of genetic diversity to be within populations, while 31% of genetic diversity was between the populations indicating little gene flow. Genetic diversity was high in both South Africa and Vieques with no evidence of inbreeding depression on Vieques. These data are helpful in understanding the population dynamics of dung beetles through knowledge of the effects of agricultural practices, niche separation, and genetics.
In April, 1994, a workshop was held in Lincoln, Nebraska, to update the IPM document that resulted from a similar workshop in Manhattan, Kansas, in 1979 (Anonymous 1979). The workshop was initiated by Dr. Ralph A. Bram, USDA National Program Leader, and organized by Drs. Gustav D. Thomas, USDA-ARS, Lincoln, and John B. Campbell, University of Nebraska, North Platte. Participants were charged with assessing the current status of IPM programs for pests of veterinary importance, identifying needs for program improvements, and recommending future research and extension priorities. Participants, invited from federal and state government research and extension organizations, and the private sector, from the U.S. and Canada, were selected because of their expertise in various sectors of the field of veterinary entomology.
IPM needs of eight animal commodity groups were addressed at the Lincoln workshop: 1) poultry; 2) dairy cattle; 3) range beef cattle; 4) confined beef cattle; 5) swine; 6) sheep and goats 7) horses; and 8) dogs and cats. A subcommittee representing each commodity group prepared the chapters contained in the report. Formats vary somewhat from one chapter to another according to the subcommittees' needs, however each chapter contains an overall summary at the beginning, followed by a discussion of the major pests, research and extension needs, and issues pertaining to the animal group. The texts for these chapters were originally prepared in 1995 and updated in 2000-2001.
References
Anonymous. 1979. Proceedings of a Workshop on Livestock Pest Management: To Assess National Research and Extension Needs for Integrated Pest Management of Insects, Ticks, and Mites Affecting Livestock and Poultry, March 5 7, 1979, Kansas State University, Manhattan, Kansas. USDA, 322pp.
Gene therapy offers the prospect of efficient and highly specific therapy of cancer. Vectors for introduction of therapeutic genes into target tissue can be broadly classified into viral and non-viral vectors. Viral vectors provide highly ef- ficient gene delivery technique, but there are some major concerns regarding their safety for patients. Non-viral techniques involve delivery of naked plasmid DNA into tissue using physical methods, such as electroporation or gene gun technique or deliveries mediated by chemical carriers, for example cationic polymers or lipids. Non-viral methods provide safer, but less efficient alternative compared to viral DNA delivery. Electroporation is method for delivery of various molecules into the cells by transiently increasing permeability of cell membrane using application of controlled external electrical field to the cells. Electroporation-based DNA delivery or elec- trogene therapy involves injection of plasmid DNA into target tissue, followed by application of controlled electric pulses. In electrogene therapy of cancer, therapeutic genes are usually transferred either intratumorally or intramusculary. Until now, electrogene therapy using a variety of therapeutic genes, mostly encoding cytokines, but also antiangiogenic factors, suicidal and apoptosis inducing genes has shown promising results for effective cancer therapy in preclinical studies.
The dung fly Neomyia cornicina (Fabricius) fed on either control dung or dung containing 0.15 μg g−1 ivermectin were mated in the following combinations: (a) control male × control female, (b) control male × ivermectin-fed female, (c) ivermectin-fed male × invermectin-fed female and (d) ivermectin-fed male × control female. Frequency and duration of mating attempts by males during 10 min mating trials were significantly higher when males were placed with control females, irrespective of male treatment. There was no significant difference between groups in the frequency and duration of all other behaviours observed. There was a significant effect of mating combination on the percentage of females that laid eggs, with most laying in groups where females were controls (groups a and d). There was also significant effect of mating combination on the time to first oviposition, with control females mated with control males (group a) laying earliest. Egg batch size was unaffected by treatment group. At the end of the experiment, all females were dissected and the number, size and yolk content of the terminal oocytes were measured. There was no effect of treatment group on any of these parameters. Results of this study indicate that female exposure to ivermectin was of greater importance than male exposure in altering male mating behaviour and reducing fecundity. Ivermectin in cattle dung could therefore lower reproductive output of this species even when only one of a pair was exposed to the drug.
Competition in cattle dung pads between two dung beetles, Onthophagus ferox Harold and Onthophagus binodis Thunberg, and the bush fly, Musca vetustissima Walker, was investigated in laboratory experiments, to determine why spring fly abundance in the field did not fall following the introduction of O. binodis.
At low beetle densities, the number of eggs laid by each species was reduced by the second species. A similar amount of dung was buried by each species alone or by both together.
At high beetle densities O. binodis egg production was substantially affected by each additional O.ferox , but O.ferox egg production was not affected by each additional O.binodis. Asymmetric competition occurred because O.ferox buried more dung than O.binodis , and a greater proportion in day 1 (pre‐emptive dung burial).
O.ferox caused greater M. vetustissima egg‐puparia mortality than O. binodis. Mortality mostly occurred in young M. vetustissima larvae less than 1 day old. Total egg‐puparia fly mortality was correlated better with the dung buried on day 1 than dung buried on day 8 (pre‐emptive dung burial). O.binodis did not add to fly mortality by O.ferox at high densities because of asymmetric competition between the beetles.
IntroductionSatisfying data needs to inform conservation practiceThe role of dung beetles in applied biodiversity research in human-modified landscapesDung beetle conservationSome ways forward
Avermectins and their metabolites are excreted mainly in the faeces; they do not readily move from the site of dung deposition because of their low solubility in water and their tight binding to organic matter. Avermectins degrade in the environment through photodegradation and aerobic breakdown by soil organisms. The dung mesofauna potentially exposed to avermectin residues includes insects, earthworms, springtails, mites and nematodes. These organisms occupy a variety of different niches within the ecosystem and the faunal composition changes as the pats age. Some members of this fauna act in concert with soil microbial flora and assist in the breakdown of dung and consequent nutrient re-cycling on pasture. There are marked seasonal patterns of faunal abundance and behaviour which affect their relative importance in the decomposer community. Some species of the coprophagous insect fauna, particularly in the larval stages, can be adversely affected by the presence of avermectin residues in the faeces. Veterinary use patterns of avermectins in temperate regions indicate that peak periods of insect activity and peak times of avermectin use are often asynchronous. When avermectin usage and insect activity do coincide, the heterogeneous patterns of administration to livestock and the focus of treatment on young animals result in the deposition on pasture of faeces which are predominantly free of avermectin residues. Results of large scale, long term studies indicate that, even under conditions of relatively high levels of avermectin use in cattle, the impact on non-target insect populations and their function is limited.
Objective To assess the toxicity to insects of drug residues excreted in cattle faeces following treatment with deltamethrin.
Design Bioassays were performed on one species of dung-breeding fly (Musca vetustissima) and two species of dung beetle (Onthophagus binodis and Euoniticellus fulvus).
Animals Cattle on properties near Kangaroo Valley, Canberra and Gundagai were treated with pour-on formulations of deltamethrin. Untreated animals acted as controls.
Procedures Faeces from treated and untreated cattle were inoculated with newly emerged fly larvae or fed to adults of two species of dung beetle. Percentage survival and duration of development provided measures of the toxicity of deltamethrin residues in faeces.
Results Residues of deltamethrin were excreted in concentrations sufficient to inhibit survival of larvae of M vetustissima for 1 to 2 weeks after treatment. Peak concentrations of 0.4mg deltamethrin/kg dry weight of faeces occurred 3 days after treatment and were sufficient to kill adult beetles for at least twice this period. With one of two formulations tested, there was evidence of a reduction in dung beetle fecundity and an increase in the duration of juvenile development. A model of the effect of deltamethrin on the breeding success of dung beetles in the field suggests that a single treatment, applied when most of the population is in a non-parous condition, may cause up to 75% reduction in beetle acitivity by the end of the season. Multiple treatments at 10 or 21 day intervals may drive local populations towards extinction.
Conclusion Depending on the time and frequency of treatment, the effect of deltamethrin on insects in cattle faeces may range from negligible to catastrophic.
Ivermectin is a potent antiparasitic drug against nematode and arthropod parasites. In this study, we examined the lethal and sublethal effects of ivermectin in a freshwater oligochaete, Lumbriculus variegatus. The median lethal concentration (LC50) at 72 h after ivermectin exposure was 560 nM. Sublethal endpoints focused on several stimulus-evoked locomotor behaviors: escape reflexes controlled by giant interneuron pathways, swimming and reversal, and crawling. Swimming, reversal, and crawling are controlled by nongiant interneuron pathways. Ivermectin inhibited swimming, reversal, crawling frequency, and crawling speed in a time- and concentration-dependent manner with a mean inhibitory concentration (IC50) at 3 h of 1.1, 16, 91, and 51nM, respectively. Ivermectin at 0.3 nM also significantly decreased the frequency of helical swimming waves. Picrotoxin, a Cl− channel blocker, antagonized the ivermectin-induced decrease in swimming frequency, crawling frequency, and crawling speed. There were no adverse effects on escape reflex 3 h after exposure to 300 nM ivermectin. Electrophysiological recordings showed that ivermectin had no effects on the conduction velocity of giant fiber systems. The results indicated that locomotor behaviors controlled by nongiant locomotor pathways were more sensitive to ivermectin than pathways controlled by giant interneurons and that Cl− channels may be involved in mediating ivermectin's inhibitory effects.
The effects of avermectin [ivermectin (IVM) and doramectin (DRM)] faecal residues on dung colonization and degradation by invertebrates were evaluated during late spring in the east of La Pampa province, Argentina. The study was conducted after collection of faecal material from animals (10 steers per group) allocated to the following groups: untreated control group (CG) and groups treated subcutaneously (200 μg/kg) with either DRM (DG) or a long-acting formulation of IVM (IG). Fifty pats (550 g each) per group were collected, prepared and deposited on the field on days 3, 7, 16 and 29 post-treatment (pt). Eight pats per group were recovered after 7, 14, 21, 42, 100 and 180 days post-deposition (pd) on the field. The weight, percentage of dry matter, number of arthropods and nematodes from faeces were determined. The faecal concentrations of IVM and DRM were measured by high performance liquid chromatography (HPLC) throughout the trial period to correlate the pattern of drug degradation in dung with pd time. The total number of arthropods in dungs from CG was higher (P < 0.05) than those counted between days 3 and 29 pt in IG and DG. A decrease in the number of Coleoptera larvae (P < 0.05) between days 21 and 42 days pd was observed in both treated groups. Diptera larvae counts in CG pats were significantly higher (P < 0.05) than those obtained in treated groups in the 7- and 14-day-old pats. A lower number (P < 0.05) of Collembola, compared with pats from CG, was recovered from IG and DG pats deposited at days 3 and 7 pt and exposed from day 42. The counts of Acari in pats from treated animals were lower (P < 0.05) than those observed in CG pats at 3, 8 and 16 days pt. There were no differences neither in adult Scarabaeidae recovered nor in the proportions of dung buried and destroyed by great dung beetles. Dung specific nematodes were reduced (P < 0.05) in IG and DG pats from 3 and 7 days pt compared with those of CG pats. The comparative results shown here demonstrate that the negative effects of both IVM and DRM on dung colonization are similar. The pattern of drug degradation in the environment was very slow. High residual concentrations of both active parent compounds were recovered in dungs exposed in the field for up to 180 days pd. Concentrations as high as 13 ng/g (IVM) and 101 ng/g (DRM) were measured in faeces obtained from pats deposited on day 27 pt and exposed to the environment during 180 days. The results show a decrease in invertebrate colonization of dung recovered from IVM- and DRM-treated cattle, which is in agreement with the large drug residual concentrations measured in faeces.
Veterinary medicines may be emitted either directly or indirectly into the environment, following its use. As veterinary medicines are biologically active compounds, there is a concern that their occurrence in the environment may have an adverse impact on aquatic and terrestrial organisms. This chapter reviews the major sources by which veterinary medicines enter the environment, the fate, behaviour and occurrence of veterinary medicines in the environment and the potential effects on environmental and human health. Finally, gaps in the current knowledge are identified and recommendations provided on priorities for future research.
Este artículo es la síntesis de una revisión de la literatura concerniente a los efectos secundarios de los principales medicamentos veterinarios utilizados en el ganado, sobre la fauna no blanco. Se hace hincapié sobre el papel de los organismos del suelo (insectos coleópteros y dípteros, nemátodos del suelo y microorganismos) que degradan y reciclan los excrementos del ganado. Los insectos coprófagos en particular, favorecen indirectamente la actividad de las bacterias que mineralizan esta materia orgánica. Los residuos de ciertos medicamentos que se encuentran en la deyecciones de los animales, pueden ser tóxicos para los insectos coprófagos y perturbar el funcionamiento de los pastizales, en ocasiones con una disminución en la velocidad de desaparición del estiércol de vacas y caballos. Entre las moléculas tóxicas para los insectos se pueden citar elcoumafos, la ruelena, el diclorvos, la piperazina, diversos piretroides de síntesis, así como la mayor parte de lactonas macrocíclicas (abamectina, ivermectina, eprinomectina, doramectina) siendo la menos tóxica lamoxidectina. Por el contrario, los residuos de otros medicamentos no tienen efectos negativos sobre los insectos coprófagos, en particular aquellos de los grupos del benzimidazo l y levamiso l/morante l. Hasta muy recientemente este impacto negativo era aceptado por los ganaderos o las firmas farmacéuticas, debido a la importancia económica de la producción comercial para controlar los parásitos del ganado. La importancia de los tratamientos de rutina es discutida, considerando que una erosión silenciosa de la biodiversidad puede tener al final consecuencias sobre el funcionamiento de los pastizales.
Control of nematode parasites of livestock is focused almost entirely on the parasitic stages within the host. Current methods rely on anthelmintic drugs, but these are under increasing threat with the development of resistance covering the whole spectrum of anthelmintics amongst the important nematode species of a range of livestock. However, invariably the greatest proportion of the parasite biomass resides not within the animal hosts, but in the external environment - commonly on pasture. It is in this environment that the free-living stages are vulnerable to a range of abiotic factors (extremes in temperature and desiccation) and biotic factors (macro- and micro-organisms) that may decimate their numbers. Of the latter, there are organisms, which exert their effects either indirectly by rendering faecal deposits inimical for the development of nematode eggs through to infective larvae, or directly by acting as pathogens or by exploiting the free-living stages as a food source. Within this vast assemblage of organisms, which include microarthropods, protozoa, viruses, bacteria and fungi, could well emerge a variety of biological control agents of nematode parasites. At present, greatest interest lies with the nematode-destroying fungi. Work has progressed from Petri dishes, to plots, to paddocks with several species of the genus Arthrobotrys and Duddingtonia flagrans. These studies indicate that the voracious nematophagous capabilities of these fungi, clearly demonstrated in vitro, translate to reductions in the number of infective larvae on pasture and indicate that levels of control, comparable to conventional schemes using anthelmintics, can be achieved. The challenge now lies in developing methods of administration of fungi to animals which can be applied under practical farm conditions.
The effects of ivermectin, a semi-synthetic drug widely used for treatment of livestock parasite diseases, were observed on Culex quinquefasciatus larvae. Toxic effects and mortality evaluation were carried out after 5, 15, 30 and 60 minutes of exposure to 1, 5 or 10 ppm of ivermectin solutions. Observations were made 24 and 48 hours after the beginning of the experiment, and loss of mobility, progressive paralysis and high mortality of larvae were recorded. The observed effects of ivermectin on the mosquito larvae is probably correlated with chloride channel activation on cell membranes.
Anthelmintics and endectocides used for the treatment and prophylaxis of Ostertagia sp. in ruminants include benzimidazoles, levamisole, morantel and the avermectins and milbemycins. Most of these agents are excreted to some extent in the faeces of treated animals and it has been demonstrated that members of the avermectin/milbemycin group may have deleterious effects on non-target organisms utilising the faeces. The environmental impact of antiparasitic chemotherapy depends on the deleterious effect which the agent or its metabolites have on organisms in the locus of the excreta, the amount of active agent excreted, the temporal nature of the excretion and the stability of the ecotoxic residues. These have to be considered in the context of the overall proportion of excreted faeces from a herd which is contaminated and thus the availability of non-contaminated faeces which may act as refugia for dung utilising organisms. The contribution which weathering, faunal inhabitants, trampling by cattle and disturbance by birds have on the rate of dung degradation must also be considered. The greatest ecotoxicological risk is associated with sustained release delivery devices, delivering endectocides with potent activity against dipteran flies and coleopteran beetles. The relatively large proportion of most cattle herds excreting faeces with no endectocidal contamination is likely to reduce the impact that such treatment or prophylactic strategies have on non-target organisms.
To assess the toxicity to insects of drug residues excreted in cattle faeces following treatment with deltamethrin.
Bioassays were performed on one species of dung-breeding fly (Musca vetustissima) and two species of dung beetle (Onthophagus binodis and Euoniticellus fulvus).
Cattle on properties near Kangaroo Valley, Canberra and Gundagai were treated with pour-on formulations of deltamethrin. Untreated animals acted as controls.
Faeces from treated and untreated cattle were inoculated with newly emerged fly larvae or fed to adults of two species of dung beetle. Percentage survival and duration of development provided measures of the toxicity of deltamethrin residues in faeces.
Residues of deltamethrin were excreted in concentrations sufficient to inhibit survival of larvae of M vetustissima for 1 to 2 weeks after treatment. Peak concentrations of 0.4 mg deltamethrin/kg dry weight of faeces occurred 3 days after treatment and were sufficient to kill adult beetles for at least twice this period. With one of two formulations tested, there was evidence of a reduction in dung beetle fecundity and an increase in the duration of juvenile development. A model of the effect of deltamethrin on the breeding success of dung beetles in the field suggests that a single treatment, applied when most of the population is in a nonparous condition, may cause up to 75% reduction in beetle activity by the end of the season. Multiple treatments at 10 or 21 day intervals may drive local populations towards extinction.
Depending on the time and frequency of treatment, the effect of deltamethrin on insects in cattle faeces may range from negligible to catastrophic.
The impact of veterinary medicines on the environment will depend on a number of factors including physicochemical properties, amount used and method of administration, treatment type and dose, animal husbandry practices, manure storage and handling practices, metabolism within the animal, and degradation rates in manure and slurry. Once released to the environment, other factors such as soil type, climate, and ecotoxicity also determine the environmental impact of the compound. The importance of individual routes into the environment for different types of veterinary medicines varies according to the type of treatment and livestock category. Treatments used in aquaculture have a high potential to reach the aquatic environment. The main routes of entry to the terrestrial environment are from the use of veterinary medicines in intensively reared livestock, via the application of slurry and manure to land, and by the use of veterinary medicines in pasture-reared animals where pharmaceutical residues are excreted directly into the environment. Veterinary medicines applied to land via spreading of slurry may also enter the aquatic environment indirectly via surface runoff or leaching to groundwater. It is likely that topical treatments have greater potential to be released to the environment than treatments administered orally or by injection. Inputs from the manufacturing process, companion animal treatments, and disposal are likely to be minimal in comparison. Monitoring studies demonstrate that veterinary medicines do enter the environment, with sheep dip chemicals, antibiotics, sealice treatments, and anthelmintics being measured in soils, groundwater, surface waters, sediment, or biota. Maximum concentrations vary across chemical classes, with very high concentrations being reported for the sheep dip chemicals. The degree to which veterinary medicines may adsorb to particulates varies widely. Partition coefficients (K(d)) range from low (0.61 L kg(-1)) to high (6000 L kg(-1)). The variation in partitioning for many of the compounds in different soils was significant (up to a factor of 30), but these differences could be not be explained by normalization to the organic carbon content of the soils. Thus, to arrive at a realistic assessment of the availability of veterinary medicines for transport through the soil and uptake into soil organisms, the K(oc) (which is used in many of the exposure models) may not be an appropriate measure. Transport of particle-associated substances from soil to surface waters has also been demonstrated. Veterinary medicines can persist in soils for days to years, and half-lives are influenced by a range of factors including temperature, pH, and the presence of manure. The persistence of major groups of veterinary medicines in soil, manure, slurry, and water varies across and within classes. Ecotoxicity data were available for a wide range of veterinary medicines. The acute and chronic effects of avermectins and sheep dip chemicals on aquatic organisms are well documented, and these substances are known to be toxic to many organisms at low concentrations (ng L(-1) to microg L(-1)). Concerns have also been raised about the possibility of indirect effects of these substances on predatory species (e.g., birds and bats). Data for other groups indicate that toxicity values are generally in the mg L(-1) range. For the antibiotics, toxicity is greater for certain species of algae and marine bacteria. Generally, toxicity values for antibacterial agents were significantly higher than reported environmental concentrations. However, because of a lack of appropriate toxicity data, it is difficult to assess the environmental significance of these observations with regard to subtle long-term effects.
The present review is restricted to the collation and evaluation of information describing the excretion profile and ecotoxicity of veterinary medicines developed specifically for the control of either internal or external parasites of livestock. It identifies numerous gaps in our knowledge and highlights our poor understanding of the environmental fate of many of these chemicals, especially those developed for the control of ticks, lice, and/or biting flies. Residues of most anthelmintics are largely harmless to dung-feeding arthropods, but those of many ectoparasiticides, especially the synthetic pyrethroids, are highly toxic to fly larvae and adult dung beetles. Organophosphates, because they are metabolized extensively and eliminated mostly in urine, are considered to be unlikely to have a major impact on the development or survival of dung-dwelling organisms. The present review stresses the need for better information regarding spatial and temporal usage patterns of veterinary parasiticides, and it examines the role of ecotoxicological models for evaluating their impact on populations of dung-dependent arthropods.
Avermectins are widely used veterinary medicines. They bind strongly to faeces in their non-metabolized form and their half-life in faeces depends on field conditions. There are conflicting data regarding the behaviour of avermectins in the environment. Therefore, we investigated the degradation of abamectin and doramectin on sheep grazed pasture under field conditions in soil, soil-faeces and faeces samples from day 6 to day 70 (abamectin) or to day 50 (doramectin) after sheep treatment. Field conditions were recorded periodically during the experiment. Degradation of abamectin in sheep faeces and in soil-faeces was observed until day 60, with small amounts present in faeces until 70 days post treatment. Because the concentration of abamectin residues in soil was very low on day 6 after treatment, further significant degradation could not be measured. The concentration of doramectin in all analysed matrices decreased rapidly until day 50. It can be concluded that high concentrations of both avermectins were present during the first 20 days after treatment and that field conditions have an important role in degradation of avermectins on grazed pasture of treated animals. Clear identification of the consequences of avermectin exposure and the period of the greatest environmental risk will require further investigations.
Gastrointestinal nematodosis of cattle is a parasitic condition resulting from an immense and seemingly forever-expanding array of factors. Countless determinants influence the incidence and severity of the species-specific infections that occur in cattle, determinants that affect the free-living or environmental stages of the parasites and the parasitic stages. The vast majority of animals have a subclinical or economic level of parasitism undetectable to the eye but quantified more accurately by treatment-induced improved performance (e.g., feed efficiency, nitrogen balance, weight gain, milk production). Unfortunately, the results of treatment (effectiveness and improved animal performance) sometimes can be as varied as the parasitisms that are being treated.
An analytical procedure has been introduced to enable study of the time profile of eprinomectin excretion in sheep faeces. Eprinomectin was extracted from sheep faeces with acetonitrile, the extract was cleaned by solid-phase extraction (SPE), and, after derivatization by reaction with N-methylimidazole, trifluoroacetic anhydride, and acetic acid, eprinomectin was analysed by high-performance liquid chromatography (HPLC) with fluorescence detection. The method has a low detection limit (1.0 ng g−1 of moist sheep faeces), a low quantification limit (2.5 ng g−1 of moist sheep faeces), good recovery (in the range 78.8 to 87.1%), and good reproducibility (RSD<10%). The method was used to study the time-profile of excretion of eprinomectin in sheep faeces after a single topical administration of 0.5 mg kg−1 b.w. of the drug. Because of its good recovery, precision, and sensitivity, the method has also proved applicable to further ecotoxicological studies of eprinomectin.
Figure
Autochthonous Slovenian dairy breed sheep – Istrian Pramenka
Seasonal patterns of abundance of Musca vetustissima Walker and scarabaeine dung beetles were measured at Busselton in south-western Australia for two years before and three years after, the introduction and establishment of two species of summer-active dung beetles, Oniticellus pallipes (F.) and Onthophagus binodis (Thunberg). Previously, only a single winter-active native dung beetle species, O. ferox Harold, occurred in this area. The mean dry weight of dung beetles trapped in December (early summer) was unaffected by the establishment of the additional species, and fly populations remained high. In January, however, dung beetle dry weight increased more than 60-fold and M. vetustissima abundance fell to 12% of its previous value, essentially halving the duration of major fly problems in the area. Virtually no flies emerged from cattle dung after December, when dung beetle activity reduced egg-adult survival of M. vetustissima to only 0·5%. It is proposed that better M. vetustissima control could be achieved in much of south-western Australia by introducing additional dung beetle species that are abundant in November and December.
b
The favourability of cattle dung from a native pasture near Rockhampton, Queensland, as a food source was tested monthly in the laboratory for 2 yr using 3 dung-breeding insects: the buffalo fly, Haematobia irritans exigua De Meijere; the bush fly, Musca vetustissima Walker; and a dung beetle, Euoniticellus intermedius (Reiche). Dung produced by cattle grazing on this pasture during the summer wet season yielded larger flies of both species and more broods from the dung beetle than dung from the same pasture in winter. When reared in summer dung, the buffalo fly almost attained its maximum recorded size but the bush fly and dung beetle reached ca two-thirds maximum recorded size and brood production respectively. Bush flies failed to breed in dung collected for 4 consecutive months in winter each year but survival of buffalo flies showed no seasonal trends.
The early response of the buffalo fly to improving dung quality in late winter/early spring gives it an advantage enabling its populations to increase earlier than those of its competitors, including the dung beetle, E. intermedius.
A key to 4 native and 7 introduced species of dung beetles is provided, together with notes on distribution and biology. -from Authors
Equal numbers of newly emerged male and female Onthophagus binodis Thunberg were placed at densities from 2-100 beetles on one-litre pads of cattle dung. After one week the number of brood balls produced was counted and the volume of dung dispersed (buried and shredded) visually assessed. The surviving beetles from each box were then placed on another pad, and the process repeated until all beetles were dead. Beetle survival was not influenced by initial beetle density and fell linearly with time (P<0.001). Brood ball production/female/week did not appear to be influenced by beetle age and could be predicted from current beetle density Y=15.03e-0.045X, R2=0.42. Dung dispersal increased with increasing density up to about 35 beetles/pad, above which the proportion dispersed plateaued at about 90%. Dung burial, estimated from the number of brood balls produced/week, was on average greatest (450 ml) with 20-30 beetles/pad. The effect of density on production of brood balls was inferred to reflect the frequency of contact between adults in the pad.
This chapter presents a summary of the efficacy data that form the basis for the clinical use of abamectin (avermectin B1) in cattle. The product is formulated in the same vehicle as used for IVOMEC (ivermectin) Injection. At the present time, AVOMEC (abamectin) Injection is registered only in Australia.
Animal droppings have played an important role in our ecosystem for millions of years. In fact, they help preserve it by returning valuable nutrients to the soil as they decompose.
(1) The effects of a single therapeutic injection of the antiparasitic drug ivermectin (22,23-dihydroavermectin B1) administered to cattle at 200 μ g kg-1 bodyweight, under Danish conditions, were studied in field and laboratory experiments. (2) Faecally excreted ivermectin inhibited the development of larvae of dung-dwelling Diptera Cyclorrhapha in dung collected from cattle 0-30 days after treatment. Larvae of dung beetles (Aphodius spp.) were inhibited in dung from animals treated 1 day previously, and pupae and larvae of Diptera Nematocera were inhibited in dung from animals treated 1 and 1-10 days previously, respectively. Excreted ivermectin remained active against a laboratory strain of the housefly Musca domestica in dung pats exposed for 2 months in the field. (3) The decomposition of dung pats from recently treated heifers was delayed significantly when compared with untreated controls. No adverse effects of treatment were recorded on earthworms. Hence, the retarded decomposition rate was ascribed to the adverse effects on the primary dipteran decomposing fauna. (4) The consequences of treatment in terms of fouling of pastureland are discussed, and the need for further research on the implications of future routine use of continuous slow-release ivermectin treatments is emphasized.
Equal numbers of newly emerged male and female Onthophagus binodis Thunberg were placed at densities from 2–100 beetles on one‐litre pads of cattle dung. After one week the number of brood balls produced was counted and the volume of dung dispersed (buried and shredded) visually assessed. The surviving beetles from each box were then placed on another pad, and the process repeated until all beetles were dead. Beetle survival was not influenced by initial beetle density and fell linearly with time (P < 0.001). Brood ball production/female/week did not appear to be influenced by beetle age and could be predicted from current beetle density Y = 15.03e −0.045X , R ² = 0.42. Dung dispersal increased with increasing density up to about 35 beetles/pad, above which the proportion dispersed plateaued at about 90%. Dung burial, estimated from the number of brood balls produced/week, was on average greatest (450 ml) with 20–30 beetles/pad. The effect of density on production of brood balls was inferred to reflect the frequency of contact between adults in the pad.
RÉSUMÉ
Effets de la densité de la population sur la reproduction et la dispersion des bouses chez Onthophagus binodis au laboratoire
L'examen au laboratoire a porté sur la relation entre le nombre d'Onthophagus binodis Thunberg et le nombre de pelotes pour l'alimentation larvaire produite par femelle dans des galettes de un litre de bouse de vache. Un nombre déterminé d'insectes a été placé sur la bouse et le nombre de pelotes dénombré chaque semaine, les adultes survivants ont été dénombrés et placés sur une nouvelle galette de bouse. Cette opération a été répétée chaque semaine jusqu'à ce que tous les insectes du lot aient été morts.
La survie a diminué linéairement avec le temps sans avoir été influencée par la densité d'origine (de 2 à 100 insectes par paquet). Après une période d'une semaine précédant la reproduction, une relation non linéaire inverse entre la production de pelotes par femelle et le nombre d'insectes présents a pu être observée. Les régressions linéaires de données transformées (logarithmes de X et Y) ont été comparées pour 14 cohortes d'insectes âgés de 2 à 19 semaines. Pour des raisons pratiques, les régressions sont semblables pour les insectes de tous âges. Une fonction exponentielle négative a été utilisée pour relier la production de pelotes (Y) à la densité des insectes (X):
Y = 15,03e −0.45x avec R ² = 0,42 et F = 67,53 pour 2 et 188 df (P < 0,001).
La quantité de bouse travaillée à chaque densité a été calculée à partir du nombre de pelotes produites par semaine et le volume de galette utilisé pour faire chaque pelote. La quantité de bouse travaillée culmine à 450 ml quand 25 à 35 insectes sont dans la galette. Aux densités supérieures à 35 insectes, la plus grande partie de la galette est dispersée, mais l'essentiel de celle‐ci est fragmentée et non travaillée. Une courbe de Michaelis et Mantus a été employée pour décrire la relation entre le volume de bouse dispersée (axe Y) et le nombre d'insectes (axe X): Y = 89,29X/1 + 0,084X avec R ² = 0,64, F = 145,23 pour 2 et 162 df (P < 0,001).
La densité d' O. binodis n'a influencé significativement, ni la production de pelotes complètes (6% étaient inachevées), ni la proportion de pelotes qui contenaient des chambres d'incubation d'oeufs (86%, n = 663). Ainsi les réactions à la diversité se produisent avant le début de la fabrication de la pelote, ce qui permet de déduire qu'elles reflètent la fréquence des contacts entre adultes dans la galette.
b
Onthophagus binodis produced many brood balls from a dung pad in soil of 4% moisture, but few at 2% or 1% (wilting point 3.5%). Euoniticellus intermedius produced consistently high numbers of brood balls at all 3 soil moistures. At the 2 drier levels O. binodis placed brood balls only in the soil moistened by the dung, but E. intermedius always placed brood balls throughout the available soil. E. intermedius in dry soil produced clumps averaging 8.7 brood balls and lined the walls of the tunnels with dung, thus preventing their collapse. In moist soil both species produced brood balls singly in tunnels throughout the available soil.
Newly emerged females of Euoniticellus intermedius (Reiche) have no differentiated oocytes in their single ovariole. The eggs mature sequentially during the maturation period, and at 27°C the first egg is laid 4–8 days after emergence. The rate of oviposition increases with temperature between 18 and 32°C. The threshold for oviposition is 19·6°C, and one egg is produced for every four day-degrees above this threshold. Most females can be sorted into the nulliparous or one of three parous categories, covering the period from emergence to the time when between 75 and 127 eggs have been deposited, on the basis of the quantity of yellow body in the ovariole. The hardness of the cuticle, the degree of oocyte development, and the presence or absence of fat-body in the abdomen can be used to subdivide the nulliparous category into three parts and to recognise old or ‘spent’ beetles. The degree of wear on the tibial teeth gives an age estimate that is independent of nutritionally induced delays and with which the ovarian age can be compared. Actual age cannot be estimated in field-caught-beetles, however, since many factors besides temperature alter the rate of brood production.
Egg production by two scarabaeine dung beetles, Onthophagus binodis (Thunberg) and Onitis alexis Klug, was measured in the laboratory in relation to seasonal changes in the characteristics of the cattle dung on which they fed. Dung was collected in two areas of south-western Australia monthly between September and May. Egg production was high on dung from green annual pasture from September to November and on green irrigated perennial pasture from December to May and low on dung from dead annual pasture from December to May. O. alexis was somewhat less affected by these seasonal changes in dung characteristics than Onthophagus binodis.
Data from dung-baited pitfall traps show that dung beetles (Coleoptera: Scarabaeidae) do not discriminate against dung from sheep or cattle treated with avermectin. On the contrary, for a period post-treatment, dung from animals treated with avermectin attracted more beetles than dung from untreated animals. This effect was more marked with cattle dung than with sheep dung. The period of enhanced attractiveness of sheep dung was restricted to dung produced during the first day after treatment, whereas with cattle dung, the effect was still evident in faeces produced 25 days after treatment. Cattle dung produced from 3–25 days post-treatment caused 100% mortality in newly hatched larvae of the bushfly, Musca vetustissima Walker (Diptera:Muscidae). In dung of day 35, mortality was 93.6%. Dung collected from sheep from 1–6 days after treatment also caused 100% mortality of fly larvae, but by day 28, no toxic effects were detectable. Field observations on the colonization of cattle pats confirmed the enhanced attractiveness of dung from treated animals and suggested that departure rates from treated dung were lower than those from untreated dung. Treated pats supported higher beetle populations than untreated pats and burial was more rapid. The potentially serious implications of the enhanced attractiveness of avermectincontaminated dung are discussed in relation to the survival of dung beetle communities.
In a variety of laboratory and field experiments, avermectins have been tested against some 84 species of insects in ten orders, most of which are pests of livestock or horticultural crops or are of general nuisance value. This work is reviewed, comparing doses used, methods of application, and responses of the insects. Avermectins (abamectin and ivermectin) are toxic to almost all insects examined, although tolerance varies and death can be uncommonly slow, taking 24 h to 30 days. There is a marked absence of information on physiological processes that are affected by the pesticides, although at the cellular level they are thought to disrupt receptors for y-aminobutyric acid and glutamic acid in the central nervous system and muscular system. At high doses, treated insects are progressively immobilized, and although initially many can move when stimulated, this ability becomes lost. Some show a disturbed water balance and become distended with fluid, while others show disruption of moulting and metamorphosis. Feeding inhibition is commonly observed at sub-lethal doses. Avermectins affect many aspects of reproduction including mating behaviour, egg development, oviposition and egg hatching. The possibility is raised that these diverse disturbances are not all due to disruption of neuromuscular or central nervous system synapses, and the need for work in this area is stressed. Field studies have shown ivermectin to be most valuable in eradicating insect pests of livestock, but the use of abamectin against horticultural pests has produced less impressive results. The limited work on non-target species is discussed, and attention is drawn to some possible environmental consequences of excreted ivermectin on dung-breeding insects.
A single injection of calves with ivermectin, at the recommended anthelmintic dose rate of 200 μg/kg of body weight, was effective in killing the larvae of the dung‐breeding dipteran, Orthelia cornicina for up to 32 days post‐treatment. Newly emerged beetles of the scarabaeine dung beetle, Copris hispanus , suffered 90 % mortality in dung dropped on days two and three after injection and 27.5 % mortality in dung of day 16. Feeding activity was greatly suppressed in dung of days 1–8, but was normal in dung of days 32 and 64, in which there was no substantial mortality. In the 1–16 day treatments, survivors showed aberrant reproductive development. When ovipositing C. hispanus were fed with day 3 dung, there was no adult mortality but oviposition rate was reduced and immature survival was zero. No mortality occurred among sexually mature adults of the dung beetle, Bubas bubalus when fed for five weeks on dung collected at intervals ranging from 1–32 days after injection. Substantial mortality was recorded among newly emerged beetles of Onitis belial , following exposure to ivermectin residues. Environmental implications of these results are discussed.
Zusammenfassung
Über die Wirkungen der antiparasitischen Droge Ivermectin auf Entwicklung und Überleben der Dungfliege Orthelia cornicina (F.) sowie der Dungkäfer Copris hispanus L., Bubas bubalus (Ol.) und Onitis belial F.
Eine Einzelinjektion bei Kälbern mit Ivermectin in der empfohlenen Dosis von 200 μg/kg Körpergewicht tötete die Entwicklungsstadien der Dungfliege O. cornicina bis zum 32. Tag nach Behandlung. Frisch geschlüpfte Käfer von C. hispanus erlitten in 2 und 3 Tage nach der Injektion produziertem Dung 90 % Sterblichkeit, in Dung vom 16. Tag 27,5 %. Die Fraßaktivität der Käfer war in Dung vom 1.‐8. Tag stark gehemmt, jedoch in Dung vom 32. und 64. Tag normal, wo keine deutliche Sterblichkeit mehr bestand. In Dung vom 1. bis 16. Tag nach Behandlung zeigten überlebende Käfer aberrante Reproduktion. Wurden Eier ablegende C. hispanus mit Dung vom 3. Tage gefüttert, zeigte sich keine Adulten‐Mortalität, doch war die Eiablage‐Rate verringert und die Entwicklung von Nachkommen gleich 0. Dagegen wurde keine Mortalität unter den geschlechtsreifen Adulten des Dungkäfers B. bubalus beobachtet, wenn diese 5 Wochen lang von Dung fraßen, der zwischen dem 1. und 32. Tag nach der Injektion produziert worden war. Teilmortalität wurde unter frisch geschlüpften Käfern von O. belial beobachtet als Folge der Kontaminierung mit Ivermectin‐Rückständen. Die Umweltzusammenhänge mit diesen Ergebnissen werden erörtert.
Dung was collected 1, 2, 4, 8 and 11 weeks after cattle were treated in the prescribed manner for nematode control in the spring with either an injection of 200 μg kg-1 of avermectin B1 or a drench of levamisole hydrochloride. The avermectin B1 treatment affected survival of the bushfly, Musca vetustissima Walker, and breeding of the introduced dung beetle, Onthophagus binodis Thunberg. No bush flies survived from egg to adult in dung collected from animals treated with avermectin B1 2 weeks earlier, but survival rates returned to normal 8 weeks after treatment. Adult survival of O. binodis was not affected in dung of cattle treated with avermectin B1 but oviposition was reduced and immature survival was zero in dung from animals treated one week previously, returning to normal 8 weeks after treatment. Dung from cattle treated with avermectin B1 in summer and autumn would influence beetles little because most are not breeding then, but in spring when beetles are breeding the risk of harmful effects could be reduced by using an alternative treatment such as levamisole hydrochloride.
Beetles and mites attracted to fresh cattle dung in south western Australian pastures. CSIRO Div. Entomol. Rep. No. 34, Australia, 29 pp Effect of population density on repro-duction and dung dispersal by the dung beetle Onthophagus binodis in the laboratory. Ento-mol
- T J Ridsdill-Smith
- G P Hall
Ridsdill-Smith, T.J. and Hall, G.P., 1984. Beetles and mites attracted to fresh cattle dung in south western Australian pastures. CSIRO Div. Entomol. Rep. No. 34, Australia, 29 pp. Ridsdill-Smith, T.J., Hall, G.P. and Craig, G.F., 1982. Effect of population density on repro-duction and dung dispersal by the dung beetle Onthophagus binodis in the laboratory. Ento-mol. Exp. Appl., 32: 80-85.
Competition in dung-breeding insects Reproductive Behaviour of Insects
- T J Ridsdill-Smith
Ridsdill-Smith, T.J., 1991. Competition in dung-breeding insects. In: W.J. Bailey and T.J. Rids-dill-Smith (Editors), Reproductive Behaviour of Insects. Chapman and Hall, London, pp. 264-292.
Competition in dung-breeding insects
- Ridsdill-Smith
Beetles and mites attracted to fresh cattle dung in south western Australian pastures
- Ridsdill-Smith