Dung removal by macrofauna such as dung beetles is an important process for nutrient cycling in pasturelands. Intensification of farming practices generally reduces species and functional diversity of terrestrial invertebrates, which may negatively affect ecosystem services. Here, we investigate the effects of cattle-grazing intensification on dung removal by dung beetles in field experiments replicated in 38 pastures around the world.
View Article and Find Full Text PDFCattle treated with LongRange®, an injectable formulation of the parasiticide eprinomectin, fecally excrete insecticidal residues for an extended period post application. We examined the nontarget effect of these residues by comparing insect communities developing in dung of untreated cattle (week 0) with those developing in dung of cattle treated 1, 2, 4, 8, 12, 16, 20, and 24 or 25 weeks previously. Chemical analyses of dung showed that eprinomectin concentrations peaked at 1 week post application and were still detectable at 25 weeks.
View Article and Find Full Text PDFThe likelihood of parasitoids establishing in new geographic regions depends upon the availability of suitable host species. Identifying these hosts and the degree of their suitability is particularly important when they include species that are economically important as pests. In laboratory studies, we examined the suitability of 47 species of Lepidoptera as potential hosts of a parthenogenetic strain of the gregarious parasitoid (Hymenoptera: Braconidae).
View Article and Find Full Text PDFFollowing the introduction of cattle, exotic dung beetles (Coleoptera: Aphodiidae, Geotrupidae, Scarabaeidae) were imported into the Antipodes (Australia and New Zealand) and North America (primarily the United States) to accelerate the degradation of cattle dung on pastures. The history of dung beetle introductions between the two regions is similar but has not previously been assessed: this is important as new introductions are continuing in the regions. Here, we review these introduction programs, report on their current status, and discuss methodological advances.
View Article and Find Full Text PDFPitfall traps baited with cattle dung are commonly used to characterize local assemblages of coprophilous insects. Baits can be made fresh or be prepared in advance and kept frozen until needed. Insect recoveries are expected to decline with the age of the bait and may be affected by the use of fresh vs.
View Article and Find Full Text PDFIt is often difficult to compare studies examining the effects of endectocides on dung fauna because of different experimental approaches, for example, active ingredients (eprinomectin, doramectin, ivermectin, moxidectin) and formulations (injectable, pour-on, spiked). To gain a better understanding, we performed a quantitative meta-analysis using 22 studies to assess the overall effect of endectocide residues on the occurrence (presence or absence) and abundance of aphodiine dung beetles. Our results document a positive effect on the occurrence of adult beetles, indicating that adults tend to be attracted to dung with residues.
View Article and Find Full Text PDFKhapra beetle, Trogoderma granarium Everts, is unusual in two key respects. First, they are among the most cold hardy of stored-product insect pests even though they originate in hot and dry regions of the Indian subcontinent. Second, their larvae can enter into diapause to survive harsh environmental conditions.
View Article and Find Full Text PDFKhapra beetle, Trogoderma granarium Everts, is one of the world's most important pests of stored grain. Common in Africa and Asia, it is a quarantine insect for much of the rest of the world where methyl bromide has traditionally been used for its control. However, this ozone-depleting fumigant is now heavily restricted, and alternate methods of control are required.
View Article and Find Full Text PDFThe insecticidal activity of parasiticide residues in dung of cattle treated with a sustained release eprinomectin formulation was examined, and an improved eprinomectin dung residue extraction method is presented. Emergent insect abundance and richness were significantly reduced in all post-treatment intervals (7, 14, 28, 56, 84, 112, and 140 d), relative to pre-treatment. Emergent insect diversity was reduced for between 84 and 112 d post-treatment.
View Article and Find Full Text PDFHippoboscid flies (Diptera: Hippoboscidae) include species that are ectoparasites of birds in the Northern Hemisphere, but little is known regarding their taxonomy, parasites, avian host associations, or geographical distribution in North America. In late August of 2013 and 2014, we collected hippoboscid flies from live birds trapped in mist nets as part of a banding study in Cypress Hills Interprovincial Park in southeastern Alberta, Canada. A total of 113 birds comprising 9 species was examined in 2013.
View Article and Find Full Text PDFTemperate forest tree species that span large geographical areas and climatic gradients often have high levels of genetic variation. Such species are ideal for testing how neutral demographic factors and climate-driven selection structure genetic variation within species, and how this genetic variation can affect ecological communities. Here, we quantified genetic variation in vegetative phenology and growth traits in narrowleaf cottonwood, Populus angustifolia, using three common gardens planted with genotypes originating from source populations spanning the species' range along the Rocky Mountains of North America (ca.
View Article and Find Full Text PDFWe examined the effects of Wolbachia bacteria on the reproduction of the flour beetle Tribolium confusum (Coleoptera: Tenebrionidae) using different antibiotics and across generations. We first removed infections by rearing insects on a diet with tetracycline (T; 1.0, 2.
View Article and Find Full Text PDFCattle treated with the veterinary parasiticide ivermectin fecally excrete residues. The authors report the exposition and dissipation characteristics of these residues in dung of ivermectin-treated cattle and in soil beneath this dung on pastures in Canada, France, Switzerland, and The Netherlands. Residues were quantified for dung collected from cattle after 3 d, 7 d, 14 d, and 28 d posttreatment and subsequently exposed in the field for up to 13 mo.
View Article and Find Full Text PDFResearch on cutworms led us to explore the use of the McMorran diet to rear lepidopteran species, mainly Noctuidae, under laboratory conditions. We documented the development of 103 lepidopteran species, including 39 species not previously reported in the literature, to be reared on this diet. Given its low cost, ease of preparation, and wide species' acceptance, this diet provides a powerful tool for facilitating Lepidoptera and other insects rearing and research in the laboratory.
View Article and Find Full Text PDFThe application of veterinary medical products to livestock can impact soil organisms in manure-amended fields or adversely affect organisms that colonize dung pats of treated animals and potentially retard the degradation of dung on pastures. For this reason, the authorization process for veterinary medicinal products in the European Union includes a requirement for higher-tier tests when adverse effects on dung organisms are observed in single-species toxicity tests. However, no guidance documents for the performance of higher-tier tests are available.
View Article and Find Full Text PDFBy degrading the dung of livestock that graze on pastures, coprophilous arthropods accelerate the cycling of nutrients to maintain pasture quality. Many veterinary medicinal products, such as ivermectin, are excreted unchanged in the dung of treated livestock. These residues can be insecticidal and may reduce the function (i.
View Article and Find Full Text PDFUnlabelled: Natural systems of hybridizing plants are powerful tools with which to assess evolutionary processes between parental species and their associated arthropods. Here we report on these processes in a trispecific hybrid swarm of Populus trees. Using field observations, common garden experiments and genetic markers, we tested the hypothesis that genetic similarities among hosts underlie the distributions of 10 species of gall-forming arthropods and their ability to adapt to new host genotypes.
View Article and Find Full Text PDFRegistration of veterinary medical products includes the provision that field tests may be required to assess potential nontarget effects associated with the excretion of product residues in dung of treated livestock (phase II, tier B testing). However, regulatory agencies provide no guidance on the format of these tests. In the present study, the authors report on the development of a standardized field test method designed to serve as a tier B test.
View Article and Find Full Text PDFStudies of genetic variation can clarify the role of geography and spatio-temporal variation of climate in shaping demography, particularly in temperate zone tree species with large latitudinal ranges. Here, we examined genetic variation in narrowleaf cottonwood, Populus angustifolia, a dominant riparian tree. Using multi-locus surveys of polymorphism in 363 individuals across the species' 1800 km latitudinal range, we found that, first, P.
View Article and Find Full Text PDFCaptures of insects in pitfall traps are affected by features of trap design that may confound the interpretation of data. One such feature is a lid suspended over the opening of the trap to exclude debris and rainwater. In this study, we tested whether use of these lids affected captures of carabid beetles by altering the light conditions at the opening to the trap.
View Article and Find Full Text PDFHybrid genotypes that arise between plant species frequently have increased susceptibility to arthropod pests and fungal pathogens. This pattern has been attributed to the breakdown of plant defenses ('Hybrid susceptibility' hypothesis) and (or) to extended periods of susceptibility attributed to plant phenologies in zones of species overlap and (or) hybridization ('phenological sink' hypothesis). We examined these hypotheses by assessing the susceptibility of parental and hybrid Populus host genotypes to a leaf spot disease caused by the fungal pathogen Septoria musiva.
View Article and Find Full Text PDFPrevious research using mitochondrial haplotypes indicates that North American populations of cabbage seedpod weevil, Ceutorhynchus obstrictus (Marsham), originated from at least two separate introductions from source populations in Eurasia. We tested this hypothesis by comparing the genetic variation of symbiotic Wolbachia bacteria in C. obstrictus among seven North American and four European populations.
View Article and Find Full Text PDFIntegr Environ Assess Manag
April 2011
To register veterinary medicinal products (VMPs) as parasiticides on pastured animals, legislation in the European Union requires an environmental risk assessment to test the potential nontarget effects of fecal residues on dung-dwelling organisms. Products with adverse effects in single-species laboratory tests require further, higher-tier testing to assess the extent of these effects on entire communities of dung-dwelling organisms under more realistic field or semifield conditions. Currently, there are no documents specifically written to assist researchers in conducting higher-tier tests or to assist regulators in interpreting the results of such tests in an appropriate context.
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