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The daylily gall midge, Contarinia quinquenotata (Loew) (Diptera: Cecidomyiidae), is an ornamental pest of daylilies, Hemerocallis spp. Linneas (Asphodelaceae). Originally native to Asia, this pest was accidentally introduced to western North America, and it is believed to occur throughout other parts of North America even though its presence has not been confirmed. Using an online survey of gardeners across Canada’s “Maritimes” (the region that includes the provinces of New Brunswick, Nova Scotia, and Prince Edward Island), we determined that symptoms of the pest occurred at multiple sites across Nova Scotia, but we received no reports from Prince Edward Island or New Brunswick. Sequencing the cytochrome c oxidase 1 gene of the samples submitted by community scientists, we confirmed the daylily gall midge occurs at multiple sites across Nova Scotia. A common garden study that included 517 daylily varieties found that yellow-flowering varieties were almost twice as likely to be affected as nonyellow varieties. Early-flowering varieties were more likely to be attacked than later-flowering varieties. For each day that the date at first flowering was delayed, the likelihood of gall midge attack decreased by 16%. To avoid or mitigate damage where the daylily gall midge occurs, selecting late-flowering varieties with nonyellow flowers can be a useful complement to destructing infested flower buds.

White-tailed deer (Odocoileus virginianus) are large herbivores that thrive in urban and peri-urban landscapes. Their voracious appetite and ubiquity have made deer a significant threat to growing food in home and community gardens; features that often make important contributions towards household food security. Focusing on food availability, stability, utilization, and access, I outline how white-tailed deer threaten household food security. Deer threaten availability of food by widely consuming plants grown for human consumption. Deer threaten stability of household food security by causing spatially and temporally unpredictable food losses. Deer threaten utilization of food, through acting as sources of food-borne pathogens (i.e. Escherichia coli O157:S7). Deer threaten access to food by necessitating relatively high-cost economic interventions to protect plants from browsing. Although numerous products are commercially available to deter deer via behavioural modification induced by olfaction and sound – evidence of efficacy is mixed. Physical barriers can be highly effective for reducing deer browsing, but often come with a high economic cost. Users of community gardens benefit from fencing by receiving shared protection against deer herbivory at a significantly lower per capita cost. Among many other benefits, fenced community gardens are useful in mitigating the threats of white-tailed deer to household food security.

Body-size is an important trait for predicting how species contribute to ecosystem functions and respond to environmental stress. Using the dung beetle Onthophagus nuchicornis (Coleoptera: Scarabaeidae), we explored how variation in body-size affected ecosystem functioning (dung burial) and sensitivity to an environmental stressor (exposure to the veterinary anthelmintic ivermectin). We found that large beetles buried nearly 1.5-fold more dung than small beetles, but that mortality from exposure to a range of concentrations of ivermectin did not differ between large and small beetles. Unexpectedly, we found that exposure to low concentrations of ivermectin (0.01⁠–1 mg ivermectin per kg dung) stimulated dung burial in both small and large beetles. Our results provide evidence of ecological functioning hormesis stemming from exposure to low amounts of a chemical stressor that causes mortality at high doses.

Macrocyclic lactones (MLs) are chemical compounds administered to livestock for parasite control. These compounds are poorly metabolized and pass relatively unchanged into the dung of treated animals. When coprophagous insects such as dung beetles (Coleoptera: Scarabaeoidea) are exposed to ML residues while feeding on dung, lethal and sublethal effects are often observed. This can lead to ML residues impairing ecosystem functions that underpin agricultural production. A strategy to reduce these negative effects involves the use of compounds that offer lower risk to non-target invertebrates, such as the ML moxidectin. Considering two dung beetle species with differing sensitivities to agricultural intensification, we asked whether exposure to moxidectin residues influenced survival, reproductive output, and functioning (short- and long-term estimates of dung removal). When exposed to moxidectin, adults of the sensitive species (Geotrupes spiniger Marsham) experienced a 43% reduction in survival. In contrast, survival of the non-sensitive species (Aphodius rufipes L.) was unaffected. We were unable to determine whether exposure affected reproductive output of either species. We found little evidence to suggest moxidectin impaired dung removal. However, high densities of a species with relatively low individual functional importance (A. rufipes) can compensate for the loss of a functionally dominant species (G. spiniger). Over a longer timeframe, earthworms decomposed dung fully, irrespective of moxidectin residues. This functional redundancy reinforces that wider justifications for the conservation of biodiversity should remain integrated into agricultural policy and practice.

Intensive management practices have been widely shown to reduce the diversity and abundance of insects in agricultural landscapes. This loss has attracted considerable public and scientific interest, owing partially to the importance of insects in supporting ecosystem functions. The relative importance of diversity and abundance in underpinning ecosystem functioning, however, has not been widely explored. We examined the relative importance of diversity and abundance in ecosystem functioning using a model system of three widespread species of dung beetle (Coleoptera: Scarabaeoidea). We used a design that manipulated species richness, while also standardizing dung beetle abundance at two levels. We predicted that individual species would contribute unequally to ecosystem functioning, functioning in multi-species assemblages could be reliably predicted from single-species assemblages, and that loss of abundance would more strongly affect functioning than loss of diversity. Comparisons of functioning among three species showed that individual species contributed unequally to dung removal. In most cases multi-species assemblages provided higher levels of dung removal than predicted by single-species assemblages, demonstrating evidence of complementarity. The average effect of species richness loss had no significant effect on dung removal. In contrast a 33% loss of insect abundance corresponded to a 29% reduction in dung removal. Our work provides empirical evidence that loss of insect abundance, a widely occurring response to agricultural intensification, can have stronger consequences for ecosystem functioning than reductions in species richness. Further efforts should confirm whether this relationship is consistent across other ecosystem functions. Should this be observed, ecosystem functioning arguments could be useful in motivating agricultural producers to participate in practices such as agri-environment schemes which have potential to simultaneously conserve the diversity and abundance of insects in agroecosystems.

We examined the insecticidal activity of linalool and thymol, against diamondback moth,Plutella xylostella(Linnaeus) (Lepidoptera: Plutellidae), and whether they would synergise the activity of spinosad against this pest. Both linalool and thymol were toxic to diamondback moth larvae by topical and oral exposure, but orders of magnitude less so than spinosad. We found that low concentrations of linalool weakly synergised spinosad, increasing its toxicity more than twofold. An interaction between spinosad, and acetone meant it was not possible to identify any potential synergisms between thymol and spinosad. Our results demonstrate limited potential for thymol and linalool to act as biopesticides or synergists for managing diamondback moth.

Certain compounds of low toxicity can increase the susceptibility of an organism to toxic substances; this is known as potentiation. Demethylation inhibiting (DMI) fungicides can potentiate insecticides by impairing the production of detoxification enzymes. As both DMI fungicides and insecticides can be used near or during crop bloom, the combination may be hazardous if exposed to pollinators. Using pesticides used in blueberry or apple production, we conducted laboratory bioassays to test how combinations of field-relevant concentrations of DMI fungicides and insecticides affected honey bee ( Apis mellifera) survival. We found propiconazole, a DMI fungicide, potentiated the toxicity of the neonicotinoid insecticide acetamiprid. We found no evidence of propiconazole potentiating field-relevant concentrations of the spinosyn insecticide spinetoram. We also found that the DMI fungicide flusilazole potentiated spinetoram but not acetamiprid. A fungicidal formulation combining pyraclostrobin and boscalid did not potentiate either insecticide. Given that bees can be simultaneously exposed to multiple pesticides, understanding the potential of pesticide potentiation and synergism may help mitigate risks associated with pollinator exposure to pesticides.

1. The relationship between biodiversity and ecosystem functioning is typically positive but saturating, suggesting widespread functional redundancy within ecological communities. However, theory predicts that apparent redundancy can be reduced or removed when systems are perturbed, or when multifunctionality (the simultaneous delivery of multiple functions) is considered. 2. Manipulative experiments were used to test whether higher levels of dung beetle species richness enhanced individual functions and multifunctionality, and whether these relationships were influenced by perturbation (in this case, non-target exposure to the veterinary anthelmintic ivermectin). The four ecosystem functions tested were dung removal, primary productivity, soil faunal feeding activity and reduction in soil bulk density. 3. For individual functions, perturbation had limited effects on functioning, with only dung removal significantly (negatively) affected. Species richness did not, on its own, explain significant variation in the delivery of individual functions. In the case of primary productivity, an interaction between richness and perturbation was found: species-rich dung beetle assemblages enhanced forage growth in the unperturbed treatment, relative to the perturbed treatment. 4. Using a composite ‘multifunctionality index’ it was found that species-rich dung beetle assemblages delivered marginally higher levels of multifunctionality in unperturbed conditions; however, this benefit was lost under perturbation. Using a relatively new and robust method of assessing diversity–multifunctionality relationships across a range of thresholds, no significant effect of species richness on multifunctionality was found.

Made available in DSpace on 2020-12-12T01:45:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-12-01 Rufford Foundation Landscape structure and crop management directly affect insect communities, which can influence agriculturally relevant ecosystem services and disservices. However, little is known about the effect of landscape structure and local factors on pests, natural enemies, and biological control services in the Neotropics. We investigated how environmental conditions at local and landscape levels affect Leucoptera coffeella (insect pest), social wasps (natural enemies), and the provision of biological control services in 16 Brazilian coffee plantations under different crop management and landscape contexts. We considered microclimatic conditions, coffee plantation size, and management intensity at the local level; and forest cover, landscape diversity, and edge density at the landscape level. Pest population, wasp communities, and biocontrol services were monitored in wet and dry seasons when L. coffeella outbreaks occur. We found that the amount of forest in the surrounding landscape was more important for explaining patterns than the local environment, landscape diversity, or landscape configuration. In both seasons, L. coffeella was negatively affected by forest cover, whereas biological control and richness and abundance of social wasps increased with increasing forest cover at multiple spatial scales. Moreover, biological control was positively correlated with wasp abundance during pest outbreaks, suggesting that social wasps are important natural enemies and provide pest control services within coffee plantations. We provide the first empirical evidence that forest cover is important for the maintenance of social wasp diversity and associated pest control services in a Brazilian coffee-producing region. Instituto de Biociências Departamento de Ecologia Spatial Ecology and Conservation Lab (LEEC) UNESP - Universidade Estadual Paulista, Rio Claro Programa de Pós-Graduação em Ecologia Aplicada (Interunidades) CENA - Centro de Energia Nuclear na Agricultura Universidade de São Paulo, Piracicaba Instituto de Biociências Letras e Ciências Exatas (IBILCE) Departamento de Zoologia e Botânica UNESP - Universidade Estadual Paulista, São José do Rio Preto Department of Plant Food and Environmental Sciences Faculty of Agriculture Dalhousie University Biology Department Saint Mary’s University School for Resource and Environmental Studies and College of Sustainability Dalhousie University Departamento de Ciências Florestais ESALQ/USP - Escola Superior de Agricultura “Luiz de Queiroz” Universidade de São Paulo, Piracicaba Instituto de Biociências Departamento de Ecologia Spatial Ecology and Conservation Lab (LEEC) UNESP - Universidade Estadual Paulista, Rio Claro Instituto de Biociências Letras e Ciências Exatas (IBILCE) Departamento de Zoologia e Botânica UNESP - Universidade Estadual Paulista, São José do Rio Preto Rufford Foundation: RSG reference 18799-1

1. In temperate climates, dung is often colonised by several species of endocoprid (dwelling) dung beetles which use pats for feeding, shelter, and reproduction. 2. Endocoprid beetles aggregate even when offered patches (dung pats) of consistent age, size, and origin, suggesting that beetles themselves might influence the attractiveness of patches to members of their own species. Both pheromones, and physical changes to the structure of dung pats caused by colonising beetles have been suggested as mechanisms facilitating intraspecific aggregation, but neither of these hypotheses have been empirically tested. 3. Using a common European dung beetle (Aphodius fossor L.), we conducted a simple choice experiment designed to test whether (i) earlier colonisation by conspecifics could alter dung attractiveness and (ii) whether attraction was influenced by sex-specific signals. 4. We found that female beetles are repelled by dung colonised by conspecific females and are attracted to dung colonised by conspecific males. Male beetles show no evidence of attraction or repellence for dung colonised by either sex. Neither in females nor males was uncolonised dung found to be significantly more or less attractive than predicted by non-preference. 5. Our results suggest that for A. fossor male-produced signals may support mate finding in patchy environments, and that female-produced signals may serve to discourage subsequent colonisation by additional females.

Macrocyclic lactones (MLs) are a class of chemical compounds administered to livestock for parasite control. These compounds are poorly metabolized and are predominately excreted in dung.When coprophagous insects such as dung beetles (Coleoptera: Scarabaeoidea) are exposed to ML residues, lethal and sublethal effects are often observed. Indirectly this can lead to ML residues impairing ecosystem functions that underpin production. A strategy to reduce these negative effects involves selecting compounds that offer lower risk to non-target invertebrates such as the ML moxidectin.Considering two dung beetle species with differing sensitivities to agricultural intensification, we asked whether exposure to moxidectin residues influenced survival, reproductive output, and functioning (short- and long-term estimates of dung removal).When exposed to moxidectin, adults of the sensitive species (Geotrupes spiniger Marsham) experienced a 43% reduction in survival. In contrast, survival of the non-sensitive species (Aphodius rufipes L.) was unaffected. We were unable to determine whether exposure affected reproductive output of either species.We found little evidence to suggest moxidectin impaired dung removal. We found however, that high densities of a species with relatively low functional importance (A. rufipes) can compensate for the loss of a functionally dominant species (G. spiniger). Over a longer timeframe, earthworms fully decomposed dung irrespective of moxidectin residues.

Agriculture relies on ecosystem services, such as biological control of pests, for economic success and sustainability. Commercially managed lowbush blueberries are an important crop in eastern North America, but pest control by natural enemies has not been well studied. In this paper we address questions about consumption of two blueberry pests by ground beetles (Carabidae) that are common in blueberry fields. In the first experiment, a Poecilus l. lucublandus, Carabus nemoralis, or Pterostichus mutus beetle was placed with two blueberry spanworm larvae, Itame argillacearia, in a simple (cup only or cup + soil) or more complex (cup + soil + blueberry sprigs) treatment arena. In most cases, probability of spanworm consumption reached 100 % in simple arenas by the end of the experiment (48 h) but was 25–50 % lower in more complex arenas. In a second experiment, a male or female Pterostichus melanarius or Harpalus rufipes beetle was placed in a plastic container with saturated or dry soil into which mature blueberry maggots, Rhagoletis mendax, dropped from blueberries to pupate. Approximately 40–80 and 35 % fewer pupae were recovered when a P. melanarius and H. rufipes beetle was present, respectively, but soil moisture and beetle sex were not significant factors. Our results demonstrate that ground beetles can prey upon important blueberry pests, but suggest that consumption may be influenced by microhabitat structure.

Dung beetles mediate a variety of important ecosystem services in both natural and human-modified habitats. These services are associated with the exploitation of dung by beetles for breeding and feeding, with different functional groups using dung in different ways. While many studies have considered how individual ecosystem functions and services (primarily dung removal and seed dispersal) are affected by changes in dung beetle diversity, fewer studies have considered the consequences for multiple functions and services. We used manipulative experiments to evaluate the functional efficiency of three species of dung beetles, each representing one of the three functional groups present in temperate Europe. Standardising beetle biomass, we compared single-species treatments to a three-species mixture containing each of the species in equal biomass. We then measured three ecosystem services relevant in supporting pasture-based livestock production systems: dung removal, soil fauna activity, and soil aeration. The presence of dung beetles significantly elevated all three ecosystem services. However, delivery of each service peaked under different treatments, indicating that no single-species assemblage can provide maximum functioning across multiple services. For all three services, the three-species polyculture provided a level of functioning indistinguishable from the most efficient single-species treatment. Our results highlight the importance of considering multiple functions and services when assessing the relationship between biodiversity and ecosystem functioning, and suggest that the conservation of functional richness within dung beetle communities could play an important role in securing the delivery of multiple ecosystem services.

Intact Giardia muris cysts were subjected to consecutive chloroform/methanol and 2% sodium dodecyl sulfate (SDS) extractions, and to amyloglucosidase treatment. The SDS-insoluble, amyloglucosidase-fast cyst walls (ACW) were further incubated with chymotrypsin, trypsin, papain, or pronase. Low voltage scanning electron microscopy revealed no discernible change in the ultrastructure of the filamentous layer of the cyst wall following any of these treatments. Affinity for cyst wall-specific monoclonal antibody (Meridian Diagnostics, Cincinnati, OH) was also retained after all treatments. Periodic acid-Schiff staining and gas chromatography/mass spectrometry (GC/MS) of intact and treated cyst hydrolysates showed a significant reduction in the amount of glucose associated with the cyst (72 nmoles/10(6) intact cysts vs 1.9 nmoles/10(6) ACW) as a result of amyloglucosidase treatment, indicating that glucose is stored within Giardia as an SDS-insoluble polymer. Galactosamine was identified by GC/MS as the predominant sugar associated with both the ACW and the proteinase treated ACW (42 nmoles/10(6) ACW). High performance liquid chromatographic analysis of amino acids from intact and treated cyst hydrolysates revealed a marked reduction, but not elimination, of detectable quantities of identifiable amino acid residues (255 nmoles/10(6) intact cysts vs 6.8 nmoles/10(6) proteinase treated ACW). These results suggest that the filamentous layer of the cyst wall is primarily a carbohydrate peptide complex.

Oxygen uptake in cysts and trophozoites of the parasitic protozoan Giardia lamblia was examined. Both showed oxygen uptake activity, but that of cysts was only 10% to 20% that of trophozoites. Oxygen dependence of oxygen uptake in cysts and trophozoites showed oxygen maxima above which oxygen uptake decreased. The oxygen concentration at which the oxygen uptake rate was greatest was higher for trophozoites than for cysts. The effect of various inhibitors on cyst and trophozoite oxygen uptake suggested that flavoproteins and quinones play some role in oxygen uptake. The substrate specificities and the effect of inhibitors on G. lamblia trophozoites were similar to those observed for G. muris. Metronidazole, the drug most commonly used in treatment of giardiasis, inhibited oxygen uptake and motility in trophozoites; however, it had no obvious effect on either oxygen uptake or excystation in cysts. Menadione, a redox cycling naphthaquinone, first stimulated, then completely inhibited, oxygen uptake in cysts and trophozoites; a complete loss of cyst viability and trophozoite motility was also observed. The effect of menadione on G. lamblia may indicate that redox cycling compounds have potential as chemotherapeutic agents for the treatment of giardiasis.

Gas chromatographic (GC), mass spectrometric (MS), lectin binding and enzymatic analyses of the carbohydrates from Giardia cyst walls, intact cysts and trophozoites were performed to investigate the carbohydrate composition of Giardia cyst walls and to test the hypothesis that the Giardia cyst wall is composed largely of chitin. Galactosamine, verified by MS, was present in Giardia cyst walls and intact cysts (ca. 47 nmol 10(-6) cysts). Since not even trace amounts of it were detected in trophozoites by either GC or lectin binding, galactosamine is hypothesized to be a cyst wall-specific amino hexose. Based on the putative binding affinity of Phaseolus limensis lectin, galactosamine may be present in cyst walls as N-acetylgalactosamine. Neither glucosamine nor sialic acid were detected in as much as 11 mg dry weight of cysts, cyst walls, or trophozoites. Glucose, the most abundant carbohydrate, and ribose were detected in Giardia cysts and trophozoites. Galactose (ca. 10 nmol 10(-6) cysts) was detected in cysts but not in trophozoites. The lack of detectable levels of (1) glucosamine in cyst wall hydrolysates, (2) cyst staining by Calcofluor M2R, (3) endogenous chitinase activity and (4) N-acetylglucosamine when cysts served as a substrate for exogenous chitinase suggests that the Giardia cyst wall is not composed largely of chitin as previously reported. beta-N-Acetylgalactosaminidase, EC 3.2.1.32, activity was detected in cysts and trophozoites and represents the first carbohydrate splitting hydrolase detected in Giardia.

Giardia lamblia, an aerotolerant anaerobe, respires in the presence of oxygen by a flavin, iron-sulfur protein-mediated electron transport system. Glucose appears to be the only sugar catabolized by the Embden-Meyerhof-Parnas and hexose monophosphate pathways, and energy is produced by substrate level phosphorylation. Substrates are incompletely oxidized to CO2, ethanol and acetate by nonsedimentable enzymes. The lack of incorporation of inosine, hypoxanthine, xanthine, formate or glycine into nucleotides indicates an absence of de novo purine synthesis. Only adenine, adenosine, guanine and guanosine are salvaged, and no interconversion of these purines was detected. Salvage of these purines and their nucleosides is accomplished by adenine phosphoribosyltransferase, adenosine hydrolase, guanosine phosphoribosyltransferase and guanine hydrolase. The absence of de novo pyrimidine synthesis was confirmed by the lack of incorporation of bicarbonate, orotate and aspartate into nucleotides, and by the lack of detectable levels of the enzymes of de novo pyrimidine synthesis. Salvage appears to be accomplished by the action of uracil phosphoribosyltransferase, uridine hydrolase, uridine phosphotransferase, cytidine deaminase, cytidine hydrolase, cytosine phosphoribosyltransferase and thymidine phosphotransferase. Nucleotides of uracil may be converted to nucleotides of cytosine by cytidine triphosphate synthetase, but thymidylate synthetase and dihydrofolate reductase activities were not detected. Uptake of pyrmidine nucleosides, and perhaps pyrimidines, appears to be accomplished by carrier-mediated transport, and the common site for uptake of uridine and cytidine is distinct from the site for thymidine. Thymine does not appear to be incorporated into nucleotide pools. Giardia trophozoites appear to rely on preformed lipids rather than synthesizing them de novo.(ABSTRACT TRUNCATED AT 250 WORDS)