Ivermectin residues in cattle dung impair insect-mediated dung removal but not organic matter decomposition

1. Veterinary parasiticide residues in livestock dung have been repeatedly shown to negatively affect the abundance and diversity of dung-associated insects. While these losses are concerning from a conservation perspective, they can also translate to impairment of ecosystem functions in agricultural landscapes (e.g. nutrient cycling, primary productivity and greenhouse gas mitigation). 2. Most research focusing on decomposition-related ecosystem functioning has focused on dung beetles (Coleoptera: Scarabaeoidea) while other insects, particularly flies, have received comparatively less attention. 3. Using mesocosms, this study manipulated the insect groups colonising cow dung (beetles only, flies only, beetles and flies together, and an insect-free control). Half of the insects were exposed to 1 mg kg⁻¹ ivermectin in dung, while the other half were exposed to ivermectin-free dung. Dung decomposition (mass of organic matter lost) and dung removal (change in the dry mass of the dung pat attributed to both dung decomposition and burial) were measured. 4. Comparison of beetles and flies in ivermectin-free dung showed that beetles removed nearly twice as much dung as did flies. Comparison of dung removal across all treatments showed that ivermectin residues significantly reduced dung removal provided by beetles by 47% and dung removal provided by beetles and flies together by 32%. 5. Organic matter decomposition was not significantly affected by insect colonists or by the presence of ivermectin, indicating that organic matter decomposition can occur independently of insect activity and chemical perturbations.     

Deposition and decomposition of cattle dung in forest grazing in southern Kyushu, Japan

This study monitored deposition and decomposition of cattle dung in a grazed young Chamaecyparis obtusa (an evergreen conifer) plantation in southwestern Japan, as a part of exploring the impacts of livestock in the forest grazing system. Animals defecated 10–19 times hd⁻¹ day⁻¹, producing feces of 2.2–3.5 kg DM and 33–73 g N per animal per day. The DM and N concentrations of feces ranged from 157–207 g DM kg⁻¹ and 14.8−23.1 g (kg DM)⁻¹, respectively. Occurrence of defecation was spatially heterogeneous, with feces being concentrated mainly on areas for resting (forest roads, ridges and valleys) and moving (forest roads and along fence lines). Decomposition of dung pats was considerably slow, showing the rates of 1.37–3.05 mg DM (g DM)⁻¹ day⁻¹ as DM loss. Decomposition was further slower on the basis of N release, 0.51–1.63 mg N (g N)⁻¹ day⁻¹, resulting in steadily increased N concentrations of dung pats with time after deposition. The results show that introduction of livestock into a forest (i.e., forest grazing) may limit nutrient availability to plants, by redistributing nutrients into areas with no vegetation (bare land and streams) and by establishing a large N pool as feces due to an imbalance between deposition and slow release, though further studies are necessary for investigating the occurrence of slow dung decomposition in other forest situations.     

粪甲虫对绢蒿荒漠春秋两季牛粪分解的影响

为明确绢蒿荒漠草地牛粪的分解规律,分别在5月(春季)和9月(秋季)设置不同堆置时间点(0、7、29、48、58 h),明确粪便理化性质变化规律,同时设置不同开口的网笼(无网笼、上下开口、上开口、全封口),探讨各生态功能类群粪甲虫对粪便分解的影响.结果表明:春季的粪甲虫种类数显著高于秋季,秋季的粪甲虫数量显著高于春季.春...     

A simple assay to determine the nutritional suitability of cattle dung for coprophagous beetles

An assay using extracted dung fluid was developed to provide an objective method of assessing the suitability of cattle dung for beetle Euoniticellus intermedius. Fluid was extracted from whole dung by twisting gauze-wrapped samples by hand, or by use of an hydraulic press set sequentially at 2 MPa, 6 MPa and 10 MPa. Artificial dung was made by adding dung fluid to shredded fibre-board in a 15:1 weight ratio. The rate of brood-ball (= egg) production by female E. intermedius fed on the artificial dung made from fluid extracted by the hydraulic press at 2 MPa was the same as that on natural whole dung. Reproductive performance on all artificial dungs was significantly correlated with the percent dry matter content of the dung fluid used in the mixture. Thus the percent dry matter in the fluid extracted at 2 MPa pressure provides an objective measurement for comparing the quality of different dungs as food for adult E. intermedius, without the need for performing bioassays. The results confirm that the fluid component of dung is the major source of nutrition for adult dung beetles.Deceased February 1986.     

Isolation of propionate degrading bacterium in co-culture with a methanogen from a cattle dung biogas plant

Various anaerobic hydrolytic and methanogenic bacteria active in cattle dung biogas plants are reported in the literature. Anaerobic bacteria with ability to use volatile fatty acids constitute a vital bridge between hydrolytic bacteria and methanogenic bacteria. The present paper describes the isolation ofSyntrophobacter wolinii a propionate degrading bacterium in co-culture with a hydrogen utilizing methanogenviz.,Methanobacterium formicicum from the fermenting slurry of cattle dung biogas plant. Earlier studies on propionate and butyrate degradation indicatedMethanospirillum hungatei as the hydrogen utilizing partner of the co-culture whereas in the present studies this was not the case. Temperature 35° C, pH 7.5 and 20 mM of propionate were found optimal for growth and activity of co-culture.     

Asymmetric competition in cattle dung between two species of Onthophagus dung beetle and the bush fly, Musca vetustissima

Abstract.

• 1 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.
• 2 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.
• 3 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).
• 4 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.

     

A novel macrocyclic lactone with insecticidal bioactivity from Streptomyces microflavus neau3

A novel macrocyclic lactone (1) was isolated from the fermentation broth of Streptomycesmicroflavus neau3, and the structure was elucidated by extensive spectroscopic analysis. Compound 1 showed high acaricidal activity against adult mites (IC(50)=11.1 μg mL(-1)), and nematocidal activity against Caenorhabditis elegans (IC(50)=17.4 μg mL(-1)), especially the acaricidal activity against mite eggs with an IC(50) of 37.1 μg mL(-1), which was relative higher than that of the commercial acaricide and nematocide milbemycins A(3)/A(4).     

Fungal macrolides: Structure determination and biosynthesis of achaetolide,a lactone from Achaetomium cristalliferum

The structure of a new ten-membered lactone, achaetolide, isolated from cultures of Achaetomium cristalliferum is deduced from its mass and NMR spectra and from the study ofsomederivatives. The ¹³C NMR spectra of achaetolide enriched with [1-¹³C], [2-¹³C] and [1, 2-¹³C] acetate established its formation from eight intact acetate units via a precursor octaketide chain.     

A functional classification for analysis of the structure of dung beetle assemblages

Abstract. 1. Regional scarabaeid dung beetle assemblages in southern Africa may contain over 100 species, ranging in live weight from 10 mg to 10 g. These show a wide variety of dung-use and reproductive strategies.
2. To facilitate analysis of these diverse assemblages, a system of classification analogous to guilds is proposed. Scarabaeid dung beetle species are allocated to one of seven functional groups (FGs) according to the way they use and disrupt dung. Each group therefore contains a set of species which are functional analogues of each other. This classification provides a conceptual framework within which to analyse the structure of dung beetle assemblages and the interactions between dung beetles and other dung-breeding species such as coprophagous flies.
3. There is a clear hierarchy of functional groups in their ability to compete for dung. Competitively dominant groups such as the large ball rollers (FG I) and fast-burying tunnellers (FG III) are mostly large, aggressive beetles which rapidly remove dung from the pad. The smaller ball rollers (FG II) are also effective competitors for dung. Subordinate groups are those which bury dung slowly over many days (FG IV and V) and those which breed inside the pad (FG VII, endocoprids). Kleptocoprids (FG VI) breed in dung buried by other beetles and so are not part of the hierarchy.
4. The use of this classification is illustrated by reference to three contrasting assemblages of dung beetles in a summer rainfall region of southern Africa. The potential of these beetles for biological control of dung-breeding flies is discussed.     

荒漠草原马粪中粪金龟子组成及分解作用

2007年4-10月,采用野外和室内实验相结合的方法,研究了荒漠草原马粪中的粪金龟子群落组成和对马粪分解的影响.共捕获粪金龟子13528头,隶属于3科4属26种,优势种为符号蜉金龟(Aphodius comma),占总捕获量的88.5%,不同季节粪金龟子群落组成明显不同;在鲜马粪中活动的粪金龟子以粪居型蜉金龟为主,在鲜马粪堆置3d时种数和个体数达到最高,6d后全部离开;马粪经过136 d分解,残留率为52.5%,残留粪样中氮和磷释放较慢,钾释放较快;结合室内分解实验的结果,认为粪金龟子主要通过在马粪中活动对其分解产生影响,并与风蚀作用成为荒漠草原马粪块破碎的重要动因,主要发生在春季和秋季.     

Some effects of rearing the yellow dung fly Scatophaga stercoraria in cattle dung containing invermectin

Invermectin was added to cattle dung in controlled concentrations like those found in the pats of injected cattle, and the medium was used to rear larvae of the dung fly Scatophaga stercoraria. Ivermectin at 0.036 ppm (wt/wet weight) debilitates 50% of the larvae within 48 h. At 0.015 ppm, 50% of the larvae are unable to pupariate, while at 0.001 ppm, 50% of the larvae fail to reach the adult stage. Adults produced from larvae reared in pats containing 0.0005 ppm invermectin show high levels of fluctuating asymmetry in wing characteristics as well as deformities in the wing veins themselves. The data are discussed in relation to the effects of excreted ivermectin on pastureland biology.     

半干旱草原大中型土壤动物在畜粪分解中的作用

土壤动物是陆地生态系统的重要组分, 在有机质分解过程中具有重要作用。目前有关土壤动物在生态系统分解中的作用研究主要聚焦于植物凋落物的分解, 而对动物粪便分解的研究稀少。本研究在内蒙古典型草原设置了马粪和牛粪分解原位实验, 使用不同孔径的金属隔离网排除不同体型大小的土壤动物, 通过测定大中型土壤动物对畜粪分解过程中质量损失、碳氮含量和微生物呼吸以及土壤养分动态变化的影响, 解析其在分解中的作用。设置5个处理, 即CK, 仅土壤, 无粪; T0, 粪添加+0.425 mm隔离网(排除了粪居型和掘洞型粪金龟和中型土壤动物); T1, 粪添加+1 mm隔离网(排除了粪居型和掘洞型粪金龟); T2, 粪添加+2 mm隔离网(排除了掘洞型粪金龟); T3, 仅粪添加(不排除土壤动物)。结果表明: (1)在畜粪分解60天内, 土壤动物对畜粪的干质量损失没有显著的促进作用(P > 0.05); 相反, 在畜粪分解360天, 不隔离土壤动物处理(T3)显著地提高了牛粪干质量损失(P < 0.05), 而降低了马粪干质量损失(P < 0.05)。(2)在畜粪分解的60天内, 畜粪中碳和氮含量下降速度在有土壤动物存在的情况下(T3)快于隔离土壤动物(T0和T1)。(3)两种畜粪添加增加了土壤微生物的呼吸, 且这种增加趋势在实验的第15天和第30天在土壤动物存在时(T3)最明显。(4)与对照(CK)相比, 马粪添加处理提高了土壤速效氮、有机碳的含量和土壤含水量, 且这种增加趋势在排除掘洞型粪金龟(T2)和不排除土壤动物(T3)条件下表现更显著(P < 0.05), 而牛粪添加处理没有明显改变这些指标(P > 0.05)。研究表明, 分解初期粪金龟的取食和活动会改变畜粪的理化性质, 进而影响分解后期土壤生物在畜粪分解中的作用。     

Molecular analyses of methanogen diversity associated with cattle dung

Methanogen communities were characterized in cattle dung of different ages by using a culture-independent approach. Community structures were determined by the phylogenetic analyses of methyl-coenzyme M reductase A (mcrA) clones of fresh, 8-month-old, and 24-month-old-dry dung samples. The clones in the mcrA libraries of fresh and 8-month old dung samples were identified as belonging to Methanomicrobiales, Methanobacteriales, and Methanosarcinales. However, clones in the library of 24-month-old dung were not affiliated to Methanomicrobiales. Anaerobic digestion of 2-month-old dung produced only 15% less methane compared to fresh dung which indicated the possibility of using dry dung to fuel the biogas plants in areas where unavailability of fresh dung hinders their continuous functioning. Our results first time showed the presence of viable methanogens in dry cattle dung stored for prolonged periods of time.     

松嫩草地牛粪中大型节肢动物种类组成及种群动态变化

研究并分析了松嫩草地牛粪中大型节肢动物种类组成及动态变化.结果表明,在草地牛粪中共调查到大型节肢动物7目20科43种,以鞘翅目、膜翅目和双翅目为主.依其食性不同,分为粪食性型(8科19种)、腐食性型(4科4种)、植食性型(4科6种)、捕食性型(5科11种)、杂食性型(2科5种)、尸食性型(1科1种)和寄生性型(1科1种).根据鞘翅目金龟总科中营粪食性型生活的粪甲虫对牛粪利用方式的不同,分为外生粪甲虫(6种)、内生粪甲虫(5种)、远生粪甲虫(2种)和偷窃寄生粪甲虫(1种).除了双顶嗡蜣螂,牛粪中大型节肢动物数量与鲜牛粪重量具有显著正相关关系(p＜0.01).粪食性型种类数和个体数量随鲜牛粪堆置时间的延长而迅速减少,7d后消失,其个体总数量与鲜牛粪堆积时间呈显著的负相关关系(p＜0.01),而与牛粪含水量呈显著正相关关系(p＜0.01),各种大型节肢动物因其食性不同在鲜牛粪中占据不同的生态位.鲜牛粪中大型节肢动物以粪食性型占绝对优势,而干牛粪中则以捕食性型和杂食性型为主.牛粪中大型节肢动物种群季节动态变化受温度、降水量与牛粪含水量影响,鲜牛粪中大型节肢动物优势种为直蜉金龟(69.25%)和肖秋家蝇与东方角蝇幼虫(25.12%).4、5、6月份和9月份,优势种为直蜉金龟,7月和8月份,优势种为蝇幼虫.     

北方草地牛粪中金龟子的多样性

2006年5—9月,在内蒙古鄂温克族自治旗(典型草原)、内蒙古科尔沁左翼后旗(沙地草原)和吉林省长岭县(草甸草原)3种放牧草地中,采用陷阱法和野外牛粪解剖手捡法采集牛粪中的金龟子,共采集金龟子75981头,分属9科43种。对其进行多样性分析,结果表明:长岭和鄂温克族自治旗牛粪生境中的优势种均是黄缘蜉金龟Aphodius sublimbatus(Motschulsky)(分别占各自生境捕获个体数的88.188%和93.547%),科尔沁左翼后旗的优势种为双顶嗡蜣螂Onthophagus bivertex Heyden(67.067%)、小蜉金龟Aphodius pusillus(Herbst)(14.524%)和独角凯蜣螂Caccobius unicornis(Fabricius)(10.264%)。科尔沁左翼后旗牛粪中金龟子的Simpson指数、Shannon-Wiener指数和均匀度指数在3种草地中均最高,长岭次之,鄂温克族自治旗最低。3种草地牛粪中金龟子的物种数与其丰富度相一致:长岭>科尔沁左翼后旗>鄂温克族自治旗。Sorenson群落相似性系数在0.458—0.578之间。     

Resource shifts in Malagasy dung beetles: contrasting processes revealed by dissimilar spatial genetic patterns

The endemic dung beetle subtribe Helictopleurina has 65 species mostly in wet forests in eastern Madagascar. There are no extant native ungulates in Madagascar, but three Helictopleurus species have shifted to the introduced cattle dung in open habitats in the past 1500 years. Helictopleurus neoamplicollis and Helictopleurus marsyas exhibit very limited cytochrome oxidase subunit 1 haplotype diversity and a single haplotype is present across Madagascar, suggesting that these species shifted to cattle dung in a small region followed by rapid range expansion. In contrast, patterns of molecular diversity in Helictopleurus quadripunctatus indicate a gradual diet shift across most of southern Madagascar, consistent with somewhat broader diet in this species. The three cattle dung-using Helictopleurus species have significantly greater geographical ranges than the forest-dwelling species, apparently because the shift to the currently very abundant new resource relaxed interspecific competition that hinders range expansion in the forest species.     

A review of competition in north temperate dung beetle communities

Abstract. 1. Studies of north temperate dung beetle communities frequently invoke competition as an influential ecological process. In this review, the evidence for competition in north temperate dung beetle communities is evaluated and the role of competition as a factor affecting community structure is assessed.
2. Resource limitation and the evidence for interspecific competition are assessed by collating the available experimental and observational evidence for both the adult and larval stages of the dung beetle life cycle. The role of competition as a structuring force in dung beetle communities is discussed under the following headings: niche dynamics, migration to and from individual pats, the aggregation model of co-existence, and metapopulations.
3. Some of the main conclusions are that competition for space is much more likely to occur than competition for food; the effects of competition on community structure are poorly understood; several of the influential studies of competition in north temperate dung beetle communities need to be evaluated carefully. The differences in ecology between tropical and temperate dung beetle communities are clarified.
4. As priorities for future research, resource utilisation and competition should be researched experimentally: density-dependent relationships should be investigated, particularly for the larval stages, as should competitive interactions with other dung fauna. If such experimental approaches establish convincingly the occurrence of competition, then the extent of competition in the field and under real world conditions needs to be established. A functional group classification of dung beetles and other dung fauna is described, which may improve the generality of interpretation from individual, site-specific results.     

内蒙古典型草原家畜粪中的粪金龟子群落特征

2008年6月-2009年9月,在内蒙古典型草原放牧区,分析了马、牛和羊鲜粪中粪金龟子的物种多样性、群落结构、功能群和取食偏好.共捕获粪金龟子7805头,隶属于3科4属32种,优势种为符号蜉金龟(Aphodius comma)、游荡蜉金龟(Aphodius erraticus)和泥蜉金龟(aphodius sordec...     

降水量对川西北高寒草甸牦牛粪分解速率的影响

青藏高原高寒草甸的降水年际变化很大,而且在未来全球气候变化的背景下可能进一步增大.为了研究降水量变化对川西北高寒草甸牦牛粪分解的潜在影响,通过塑料膜覆盖(去除降水)、模拟额外增水(增水量为实际降水量的50％)和对照(野外无干扰情形)形成3种不同的水分处理.测定了牛粪的含水量、干重及氮磷含量,并统计了主要分解者(手捡法获取粪食性甲虫及其幼虫)的种类和数量.结果发现:覆盖处理显著地降低了牛粪含水量、牛粪中的粪食性甲虫数量与牛粪分解量,但增水处理并没有显著影响牛粪的分解进程,可能与实验期间降水量较高有关.在牛粪分解前期,粪食性甲虫数量与牛粪含水量之间正相关,而牛粪分解量与粪食性甲虫数量之间正相关,说明牛粪含水量的高低影响了粪食性甲虫数量,进而决定了牛粪分解量.但是,降水量的人为增加或减少均没有显著地改变牛粪中的全氮和全磷含量.总体上看,在高寒草甸的放牧生态系统中,降水量的减少将会降低牛粪的分解速率、延长牛粪分解过程,从而可能会降低生态系统的生产力水平.     

内蒙古典型草原马粪分解特征

2008年6月-2009年9月,采用人工堆置于地表和埋入地下2种处理方法,研究了内蒙古典型草原马粪的分解特征.结果表明:在一块面积约47 hm2草场中,自由放牧100匹纯血马的情况下,马粪月输入量约为48.8 kg·hm-2,年输入量为277.1 kg·hm-2;人为控制的野外分解实验表明,马粪分解中质量损失主要发生在0～60d,损失率为45.0％,之后损失率变化较小;鲜马粪中有机物总量为77.0％,分解60d和330 d减少到48.7％和28.3％;鲜马粪中氮素以有机态为主,矿化和释放速度较慢;而磷素以无机态为主,释放速度较快.马粪埋入地下处理,可以消除风蚀和放牧牲畜践踏对粪块的破碎作用,同时改变了水蚀作用对粪中养分浓度的影响,但对有机质矿化无明显作用.