The plasma and fecal concentrations ofeprinomectin weredetermined in cattlefollowing topical administrationat a dose rate of 0.5 mg kg−1. The maximum plasma concentrations of 12.24 ng ml−1 occurred 2 ...d after administration, and eprinomectin remained detectable in plasma 29 d after administration (0.10 ng ml−1). The maximum dung concentration of 350 ng g−1 was observed 3 d after administration and thereafter for at least 29 d (4 ng g−1). The amount of drug recovered in dung during this period was 20.50% ± 4.31% of the total administered dose. The effects of eprinomectin against the nontarget dung‐feeding Diptera Neomyia cornicina was assessed under laboratory conditions. Feces voided by cattle treated with eprinomectin were associated with high larval mortality during the first 12 d after treatment, with null emergence until day 7. The no‐observed‐effect concentration for N. cornicina was estimated to be close to 7 ± 5 ng g−1.
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.
Guilds of dung dwelling and tunneling dung beetles coexist in local assemblages in warm temperate regions, despite the tendency of dwellers to be inferior competitors. A field experiment on the Black ...Sea coast of Turkey examined the role of temporal resource partitioning in their coexistence. Standardized dung pads deposited at 4 h intervals through a 24 h period in summer were collected 12, 24, or 48 h later. Adults from 10 tunneling and seven dung dwelling species were collected. The tunnelers contributed a high proportion of both total abundance and biomass. There was a significant effect of dung deposition time and exposure period on mean tunneler abundance. Mean tunneler abundance was nearly seven times higher in dung deposited at 06:00 than at 18:00. The dwellers reduced the potential for competitive interactions with tunnelers by relatively uniform dispersal across the six dung deposition times. The distinctly different dung use patterns by dwellers and tunnelers demonstrated temporal resource partitioning. Interspecific correlation coefficients were also determined because interspecific relationships are at the core of resource partitioning. Total tunneler and dweller abundances were not correlated. Overall, there were strong positive correlations between tunneling species and low correlations between tunneling and dwelling species, and between dwelling species. The five most abundant tunnelers, from two tribes and three genera, were strongly positively correlated. There were substantial size differences among the four most abundant tunnelers that probably facilitate their coexistence.
The effects of the parasiticide ivermectin on dung and soil fauna as well as dung decomposition were assessed in a field study conducted near Madrid (Spain). Groups of cattle were treated with an ...injection of Ivomec
® at a dosage of 200
μg ivermectin
kg
−1 body weight at four different time points before collecting the fresh dung of all cattle groups on day 0. Dung pats prepared from the dung of the ivermectin-treated cattle were exposed in the field from day 0 onwards in parallel with dung pats that were prepared from the dung of untreated cattle and that was either spiked with a high concentration of ivermectin (positive control) or not spiked (negative control). Ivermectin concentrations in freshly excreted dung ranged from 0.31 to 0.81
mg ivermectin
kg
−1 dung dry weight. Ivermectin soil concentrations were highest below ivermectin-spiked dung in the uppermost soil layer with up to 0.085
mg ivermectin
kg
−1 soil dw. No ivermectin-related effects on collembolans and mites were found. A significant decrease in the abundance of adult dung beetles was observed at 0.81
mg ivermectin
kg
−1 dung dw, but the two most abundant species showed contrasting responses. For the dung beetle species,
Volinus distinctus, a no observed effect concentration (NOEC) and a median effect concentration (EC
50) of 0.50 and 0.62
mg ivermectin
kg
−1 dung dw, respectively, were determined. Dung fly larvae were the most sensitive dung fauna group as their abundance was significantly reduced in all ivermectin treatments, resulting in a NOEC of <0.31
mg ivermectin
kg
−1 dw. Staphylinid beetles were abundant in the dung, but apparently not affected by ivermectin. Dung from ivermectin-treated cattle degraded more slowly than dung from untreated cattle, resulting in a NOEC of <0.78
mg ivermectin
kg
−1 dung dw for this functional endpoint. Adult dung beetles of both dominant species were attracted to dung pats spiked with ivermectin. The mobility of ivermectin appeared to differ between dung from ivermectin-treated cattle and dung spiked with ivermectin. This finding challenges approaches to assess the fate and effect of veterinary pharmaceuticals in higher tier tests by using spiked dung. This field study detected consistent results regarding effects of ivermectin on structural and functional endpoints in the dung compartment but effects on soil microarthropods are of little relevance in comparison. This study further advances guidance on higher tier tests that is required to make the results more applicable to the environmental risk assessment of veterinary pharmaceuticals.
Le phénomène de dépérissement du thuya de Berbérie dans les trois pays du Maghreb (Maroc, Algérie et Tunisie) prend de l’ampleur depuis ces dernières décennies. Face à cette situation, nous faisons ...un bilan de santé de cette essence au Maroc et dans les autres pays du Maghreb. Peu d’études spécifiques ont été conduites sur le sujet, ce qui limite la connaissance de l’ampleur du phénomène et de son évolution. L’exploitation des documents existants et les résultats de nos propres recherches permettent cependant de tirer quelques informations de portée générale. Les aléas climatiques (en particulier les épisodes de grande sécheresse ou le froid), les attaques par des insectes ravageurs et les agressions d’origine anthropique sont les principaux facteurs de prédisposition au dépérissement. La gelée exceptionnelle de 2005, la sécheresse et les incendies ont été décrits comme étant des facteurs déclencheurs du dépérissement du thuya. Parmi les insectes, Phloeosinus aubei (Coleoptera, Scolytidae) et Ovalisia festiva (Coleoptera, Buprestidae) ont été identifiés comme étant les principaux ravageurs dans de nombreuses forêts au Maroc et en Algérie. Les résultats disponibles restent toutefois insuffisants pour décrire avec précision l’état général de santé du thuya de Berbérie. Les recherches sur ce sujet important devraient être intensifiées, basées sur un échantillonnage exhaustif par zone bioclimatique.
In recent decades, the phenomenon of dieback of the Barbary thuja in the three Maghreb countries : Morocco, Algeria and Tunisia has been growing in Tetraclinis woodland. In response to this situation, we considered that it would be useful to carry out a short review of the status of this species in Morocco and the other Maghreb countries, although few studies on the subject are available, which limits our knowledge of the extent of the phenomenon and its evolution. However, the use of existing information (published and grey literature) and the results of our own research have made it possible to highlight some information. Climatic hazards (especially periods of severe drought or cold), the attacks by insect pests and anthropogenic aggressions are the main factors predisposing to dieback. The exceptional freeze in 2005, drought and fires have been described as triggering factors for the decline of Tetraclinis. Among the insects, Phloeosinus aubei (Coleoptera, Scolytidae) and Ovalisia festiva (Coleoptera, Buprestidae) have been identified as serious pests in many forests in Morocco and Algeria. However, these results are still insufficient to accurately describe the general health status of the Barbary thuja. Research should be continued and intensified, based on extensive sampling in each bioclimatic area.
The analysis of a large census of dung beetles from the southern Alps (108 samples; 85,478 specimens belonging to 59 species) showed that 1) elevation and vegetation type (Mediterranean versus ...temperate) greatly influenced the assemblage composition, 2) spatial factors have a greater effect than monthly variability, and 3) exposure (north versus south) is a stronger determinant than vegetation structure (grassland-semi-open habitat-forest). Environmental heterogeneity results in different assemblages dominated by related species: Scarabaeinae dominate during spring and summer on south-facing nonwooded habitats; and Aphodiinae dominate from spring to autumn on north-facing slopes and in forests, but on south-facing slopes only in autumn. Scarabaeinae species have similar spatiotemporal distributions; thus, it can be assumed that this subfamily is restricted in space and time by thermal sensitivity. The colonization of high elevations by small tunnelers is due to a few species that have a broad tolerance of environmental conditions. In contrast, the temporal distribution of Aphodiinae is highly segregated, and these beetles occupy a variety of habitats because of their specialization. Analysis shows the distribution of species belonging to different subfamilies is most related to biological requirements rather than interspecific competition. RÉSUMÉ Dans le sud des Alpes, l’analyse conjointe de nombreux peuplements de bousiers (108 échantillons, 85478 spécimens appartenant à 59 espèces) a montré que: 1) l’altitude et le type de végétation (méditerranéenne ou tempérée) influence fortement la composition des peuplements; 2) les paramètres spatiaux sont plus déterminants que la variabilité temporelle; 3) l’exposition (adret ou ubac) a plus d’importance que la structure de la végétation (pelouse, lande, forêt). L’hétérogénéité environnementale génère des assemblages hautement différenciés d’espèces apparentées: les Scarabaeinae tendent à dominer largement au printemps et en été dans les habitats non forestiers des versants sud; les Aphodiinae sont au contraire très largement majoritaires en versant nord, ainsi qu’en forêt et à l’automne. Les différentes espèces de Scarabaeinae ont des distributions spatio-temporelles très similaires, et on peut supposer que cette sous-famille est, dans son ensemble, limitée dans son extension spatiale et temporelle par la thermophilie des espèces. La colonisation des altitudes supérieures par les Scarabaeinae fouisseurs est le fait de quelques espèces ayant une plus grande tolérance vis-à-vis des conditions climatiques. Au contraire, la distribution temporelle des Aphodiinae est très ségrégée et ces insectes occupent une grande variété de milieux grâce à la spécialisation étroite des espèces. L’analyse montre enfin que la distribution des espèces appartenant aux différentes sous-familles est davantage induite par leurs exigences propres que par d’éventuelles interactions au sein des peuplements, et en particulier la compétition.
The species richness distribution of the French Aphodiidae was predicted using Generalized Linear Models to relate the number of species to spatial, topographic and climate variables. The entire ...French territory was studied, divided into 301 0.72 × 0.36 degree grid squares; the model was developed using 66 grid squares previously identified as well sampled. After eliminating nine outliers, the final model accounted for 74.8% of total deviance with a mean Jackknife predictive error of 10.5%. Three richest areas could be distinguised: the western head (Brittany), southwestern France, and, to a lesser extent, the northeastern region. Sampling effort should now be focused on the western head, where no square was correctly sampled, and on southwestern France, which was recognised as a diversity hotspot, both for Aphodiidae and for Scarabaeidae. The largest fraction of variability (37%) in the number of species was accounted for by the combined effect of the three groups of explanatory variables. After controlling for the effect of significant climate and topographic variables, spatial variables still explain 27% of variation in species richness, suggesting the existence of a spatial pattern in the distribution of species richness (greater diversity in western France) that can not be explained by the environmental variables considered here. We hypothesize that this longitudinal spatial pattern is due to the relevance of a western colonization pathway along the glacial-interglacial cycles, as well as by the barrier effect played by the Alps.
The phenology and reproductive cycles of seven Mexican Aphodiini dung beetles are studied. The highest abundances of individuals occurred during the wet and warm season of the year, coinciding with ...the long summer. Their abundance is reduced or beetles are in diapause, depending on the species, during the dry and cold months that mainly corresponded to winter. Five species are univoltine, and females and males emerge mature after the first rains arrive, reproduce and then they enter diapause until the following year. One species is bivoltine and is found from the beginning of the wet season until the onset of winter. The other species is multivoltine and found almost all year round, although the highest abundances are found during the summer when generations overlap. The abundances of three of the species occurring at different localities are compared.
Dung beetles are indispensable in pasturelands, especially when poor efficiency of earthworms and irregular rainfall (e.g. under a Mediterranean climate) limit pad decomposition. Although observed ...and projected species range shifts and extinctions due to climate change have been documented for plants and animals, little effort has focused on the response of keystone species such as the scarab beetles of dung beetle decomposers. Our study aims to forecast the distribution of 37 common Scarabaeidae dung beetle species in France, Portugal and Spain (i.e. more than half of the western European Scarabaeidae fauna) in relation to two climate change scenarios (A2 and B1) for the period leading to 2080. On average, 21 % of the species should change in each 50-km UTM grid cell. The highest faunistic turnover rate and a significant increase in species richness are expected in the north of the study area while a marked impoverishment is expected in the south, with little difference between scenarios. The potential enrichment of northern regions depends on the achievement of the northward shift of thermophilous species, and climate change is generally likely to reduce the current distribution of the majority of species. Under these conditions, the distribution of resource—i.e. the extent and distribution of pastures—will be a key factor limiting species’ responses to climate change. The dramatic abandonment of extensive grazing across many low mountains of southern Europe may thus represent a serious threat to dung beetle distribution changes.
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