The effect of the alternative prey, Paramecium caudatum (Peniculida: Parameciidae), on the predation of Culex pipiens (Diptera: Culicidae) by the copepods Macrocyclops albidus and Megacyclops viridis (Cyclopoida: Cyclopidae)

Biological control can be an effective tool to combat public health risks associated with mosquito-borne disease. However, target impacts of biological control agents may be reduced by biotic contexts such as the presence of alternative prey. In turn, this can impede our ability to realistically assess biocontrol agent efficacy. Here, we examine the effects of alternative ciliate prey on the predation potential of two cyclopoid copepods, Macrocyclops albidus Jurine (Cyclopoida: Cyclopidae) and Megacyclops viridis Jurine (Cyclopoida: Cyclopidae), towards larvae of the West Nile virus vector mosquito Culex pipiens Linnaeus (Diptera: Culicidae). Using functional responses (FRs; resource use under different resource densities), we demonstrate that both copepods exhibit potentially destabilising Type II FRs towards mosquito prey. However, where the alternative prey was present, we observed species-specific modulations to FR form and magnitude. For M. albidus, FRs remained Type II where ciliate prey were present, however, maximum feeding rates on mosquito larvae were reduced. Conversely, for M. viridis, FRs moved towards more stabilising Type III, whilst maximum feeding rates on mosquito larvae were not significantly reduced. Whilst both species of cyclopoid copepod were able to effectively target and consume larval mosquitoes in the presence of alternative prey, we demonstrate that overall efficacies may be reduced in aquatic habitats which contain multiple prey types. We thus advocate that biotic contexts such as prey selectivity should be integrated into predatory biocontrol agent examinations for mosquitoes which vector pathogens and parasites, to more holistically assess their efficacy

Differential interaction strengths and prey preferences across larval mosquito ontogeny by a cohabiting predatory midge

Abstract Understandings of natural enemy efficacy are reliant on robust quantifications of interaction strengths under context-dependencies. For medically important mosquitoes, rapid growth during aquatic larval stages could impede natural enemy impacts through size refuge effects. The identification of biocontrol agents which are unimpeded by ontogenic size variability of prey is therefore vital. We use functional response and prey preference experiments to examine the interaction strengths and selectivity traits of larvae of the cohabiting predatory midge Chaoborus flavicans (Meigen 1830) (Diptera: Chaoboridae) towards larval stages of the Culex pipiens (Diptera: Culicidae) mosquito complex. Moreover, we examine the influence of search area variation on selectivity traits, given its importance in consumer-resource interactions. Chaoborids were able to capture and consume mosquito prey across their larval ontogeny. When prey types were available individually, a destabilizing Type II functional response was exhibited towards late instar mosquito prey, whereas a more stabilizing Type III functional response was displayed towards early instars. Accordingly, search efficiencies were lowest towards early instar prey, whereas, conversely, maximum feeding rates were highest towards this smaller prey type. However, when the prey types were present simultaneously, C. flavicans exhibited a significant positive preference for late instar prey, irrespective of water volume. Our results identify larval chaoborids as efficacious natural enemies of mosquito prey, with which they frequently coexist in aquatic environments. In particular, an ability to prey on mosquitoes across their larval stages, coupled with a preference for late instar prey, could enable high population-level offtake rates and negate compensatory reductions in intraspecific competition through size refuge

Angst auf der Akutsomatik : Erfassung und Interventionsmöglichkeiten

Hintergrund: Bis zu 64% aller Patienten/-innen haben während der Hospitalisierung Angst. Angst kann negative Gesundheitsfolgen mit sich ziehen und den Genesungsprozess verlängern. Ziele: Das Ziel dieser Bachelorarbeit ist es, pflegegeführte Interventionen zur Erfassung und Behandlung von Angst bei erwachsenen Patienten/-innen im akutsomatischen Setting zu beschreiben. Methodik: Es wurde zwischen September 2019 und Januar 2020 eine systematisierte Literaturrecherche durchgeführt. Anhand der pflegerelevanten Datenbanken CINAHL und Pubmed sowie durch Handsuche wurden acht geeignete Studien gefunden. Hintergrundliteratur in Form von Büchern und Sekundärliteratur zur Stützung der Primärliteratur wurden in die Arbeit miteinbezogen. Ergebnisse: Sechs quantitative Studien, eine gemischte Studie und ein Artikel zur Übersicht der Messinstrumente wurden eingeschlossen. Es zeigen sich das State-Trait-Anxiety Inventory, das Beck Anxiety Inventory und die Hospital Anxiety and Depression Scale als angsterfassende Messinstrumente. Die Edukation, die Aromatherapie, Spiritualität/ Religiosität und die Pflegevisite am Bett eignen sich als angstreduzierende Interventionen. Schlussfolgerung: Die Pflege bietet durch nahen Patientenkontakt eine Schlüsselrolle in der Behandlung von Angst. Transparente Kommunikation sowie das Erkennen von Angst sind dabei essentiell

Salinity tolerance and geographical origin predict global alien amphipod invasions

Invasive alien species are driving global biodiversity loss, compromising ecosystem function and service provision, and human, animal and plant health. Habitat characteristics and geographical origin may predict invasion success, and in aquatic environments could be mediated principally by salinity tolerance. Crustacean invaders are causing global problems and we urgently require better predictive power of their invasiveness. Here, we compiled global aquatic gammarid (Crustacea: Amphipoda: Gammaroidea) diversity and examined their salinity tolerances and regions of origin to test whether these factors predict invasion success. Across 918 aquatic species within this superfamily, relatively few gammarids (n = 27, 3%) were reported as aliens, despite extensive invasion opportunities and high numbers of published studies on amphipod invasions. However, reported alien species were disproportionately salt-tolerant (i.e. 32% of brackish-water species), with significantly lower proportions of aliens originating from freshwater and marine environments (both 1%). Alien gammarids also significantly disproportionally originated from the Ponto-Caspian (20% of these taxa) when compared with all ‘other' grouped regions (1%), and principally invaded Eurasian waters, with translocations of salt-tolerant taxa to freshwaters being pervasive. This suggests habitat characteristics, alongside regional contexts, help predict invasibility. In particular, broad environmental tolerances to harsh environments and associated evolutionary history probably promote success of aliens globally

Biological control agent selection under environmental change using functional responses, abundances and fecundities; the Relative Control Potential (RCP) metric

We currently lack the capacity to rapidly and reliably predict the efficacy of biological control agents due to inadequate consistency in derivations of functional and numerical responses and potential effects of context-dependencies. Here, we propose and apply a novel metric, Relative Control Potential (RCP), which combines the functional response (FR, per capita effect) with proxies for the numerical response (NR, agent population response) to compare agent efficacies, where RCP = FR × abundance (or other proxies e.g. fecundity). The RCP metric is a comparative ratio between potential biocontrol agents, where values > 1 indicate higher relative control efficacy. Further, RCP can compare the efficacy of agents under environmental contexts, such as temperature change. We thus derived the RCP for two predatory cyclopoid copepods, Macrocyclops albidus (Cyclopoida: Cyclopidae) and Megacyclops viridis (Cyclopoida: Cyclopidae), towards larvae of the mosquito Culex pipiens (Diptera: Culicidae) under temperatures representative of current and future climate. Both copepods exhibited potentially population destabilising Type II FRs, with increasing temperatures inducing greater magnitude FRs through increased attack rates and decreased handling times. Attack rates by M. albidus were higher than M. viridis, yet handling times and maximum feeding rates were similar between the species across all temperatures. The inclusion of abundance data drives an elevated RCP of M. albidus and the integration of fecundity drives greater RCP of M. albidus at peak temperatures. Q10 values are indicative of increased feeding activity by both copepods with temperature increases, however relative feeding level increases of M. viridis slowed towards the peak temperature. We present RCP calculations and biplots that represent the comparative efficacies of the two biological control agents across temperatures. The Relative Control Potential (RCP) metric thus provides a new tool for practitioners to better assess the potential efficacy of biocontrol agents before their integration into management approaches for pests, vectors and invasive species

Combining resource population dynamics into impact assessments of native and invasive species under abiotic change

Predicting future changes in interspecific interactions continues to be a challenge for environmental managers. This uncertainty is exacerbated by increasing biological invasions and the likelihood that the strength of trophic interactions among native species will change. Abiotic variables influence predator resource utilisation and abundance as well as resource population dynamics. Currently no practical metric or impact prediction methodology can adequately account for all of these factors. Functional Response (FR) methods successfully incorporate resource utilisation rates with regards to resource density to quantify consumer-resource interactions under varying abiotic contexts. This approach has been extended to create the Relative Impact Potential (RIP) metric to compare invader vs native impact. However, this does not incorporate resource abundance dynamics, which clearly can also change with abiotic context. We propose a Resource Reproduction Qualifier (RRQ) be incorporated into the RIP metric, whereby RRQ is the reciprocal of the fraction or proportion to which reproduction (e.g. of prey species) changes under an environmental context. This modifies the RIP score to give a more informative RIPq value, which may be contextually increased or decreased. We empirically demonstrate the utility and benefits of including RRQ into impact potential predictions with an invasive species (the lionfish Pterois volitans) and two European native species (shanny fish Lipophyris pholis and lesser spotted dogfish Scyliorhinus canicula) under different abiotic contexts. Despite high FR and abundance, lionfish impacts were reduced by increasing prey recruitment at higher temperatures, however, remained high impact overall. Shanny predatory impact increased with increasing temperature and was exacerbated by decreasing prey fecundity. Two population increase scenarios (50% and 80%) were assessed for lesser spotted dogfish under predicted temperature increases, preying upon E. marinus. Both scenarios indicated heightened predatory impact with increasing predator FR and decreasing prey fecundity. Our new metric demonstrates that accounting for resource reproductive responses to abiotic drivers, in tandem with the consumer per capita and abundance responses, better estimate the magnitudes of predicted inter-species interactions and ecological impacts. This can be used in stock assessments and predictions, as well as invasive species risk assessments in a comprehensive yet user-friendly manner

The influence of microplastics on trophic interaction strengths and oviposition preferences of dipterans

Microplastic (MP) pollution continues to proliferate in freshwater, marine and terrestrial environments, but with their biotic implications remaining poorly understood. Biotic interactions such as predation can profoundly influence ecosystem structuring, stability and functioning. However, we currently lack quantitative understandings of how trophic interaction strengths and associated behaviours are influenced by MP pollution, and how transference of MPs between trophic levels relates to consumptive traits. We also lack understanding of key life-history effects of MPs, for example, reproductive strategies such as oviposition. The present study examines the predatory ability of non-biting midge larvae, Chaoborus flavicans, towards larvae of Culex pipiens mosquitoes when the latter are exposed to MPs, using a functional response (FR) approach. Transfer of MPs occurred from larval mosquitoes to larval midges via predation. Microplastics transfer was significantly positively related to predation rates. Predation by C. flavicans followed a Type II FR, with average maximum feeding rates of 6.2 mosquito larvae per hour. These and other FR parameters (attack rates and handling times) were not significantly influenced by the presence of MPs. Further, C. pipiens adults did not avoid ovipositing in habitats with high concentrations of MPs. We thus demonstrate that MPs can move readily through freshwater food webs via biotic processes such as predation, and that uptake correlates strongly with consumption rates. Further, as MPs do not deter adult mosquitoes from ovipositing, our experiments reveal high potential for MP exposure and transference through ecosystems

Calanoid copepods: an overlooked tool in the control of disease vector mosquitoes

Biological control can assist in the management of disease vector mosquitoes. However, we urgently require the identification of novel and effective agents to aid population management strategies. Quantifying interactions strengths between consumers and resources is central to our understanding of trophic stability, and is relevant within the biological control context. Previously, pPredatory biocontrol of disease vector mosquito species has previously focused extensively on cyclopoid copepods, but prey size refuge effects have been identified as a hindrance to their predatory efficacy. Calanoid copepods have yet to be comprehensively examined in the context of mosquito control, despite their high prevalence, diversity and distribution. Here, we apply functional responses (FRs; resource use as a function of resource density) to examine interaction strengthspredation efficiencies of a recently described ephemeral pond specialist species, the freshwater calanoid copepod Lovenula raynerae Suárez-Morales, Wasserman & Dalu 2015, using different size classes of larvae of the disease vector complex Culex pipiens as prey. Lovenula raynerae effectively consumed C. pipiens larvae across their ontogeny. A potentially population destabilising Type II FR was exhibited towards both early and late instar mosquitoes, indicative of a lack of prey refuge across ontogenetic stages. Attack rates were greatest and handling times lowest for early instar larvae compared to late instar larvae. These traits contrast to other copepods, commonly applied in biocontrol, which are only able to handle early instars, and in much smaller numbers. We thus advocate that calanoid copepods can exert particularly marked predatory impact on lower trophic groups, and that their use in disease vector mosquito control strategies should be further explored

Combined impacts of warming and salinisation on trophic interactions and mortality of a specialist ephemeral wetland predator

Wetlands are of enormous importance for biodiversity globally but are under increasing risk from multiple stressors driven by ongoing anthropogenic environmental change. As the trophic structure and dynamics of ephemeral wetlands are poorly understood, it is difficult to predict how these biodiverse ecosystems will be impacted by global change. In particular, warming and salinisation are projected to have profound impacts on these wetlands in future. The present study examined the combined effects of warming and salinisation on species interaction strengths and mortality rates for two ephemeral wetland species. Using an ephemeral pond specialist copepod, Lovenula raynerae Suárez‐Morales, Wasserman, & Dalu, (2015) as a model predator species, we applied a functional response approach to derive warming and salinisation effects on trophic interactions with a prey species. Furthermore, the effects of a salinisation gradient on mortality rates of adult copepods were quantified. The predatory copepod exhibited type II functional responses towards larval Culex pipiens mosquito prey, owing to high predation rates at low prey densities. Increased temperatures generally resulted in greater predator feeding rates, whilst increased salinities reduced consumption. However, the effects of temperature and salinity interacted: temperature effects on functional responses were suppressed under heightened salinities. Substantial mortality was observed in both male and female adult L. raynerae at salinity levels exceeding 10 parts per thousand. Warming and salinisation substantially altered interaction strengths in ephemeral wetland ecosystems, with implications for ecosystem function and stability. Furthermore, we demonstrated salinisation thresholds for mortality in an ephemeral wetland specialist, showing that salinisation may threaten the persistence of endemic species. The ongoing effects of warming and salinisation may therefore interact to alter trophic dynamics and species composition in ephemeral wetlands. These stressors should be considered synergistically within management practices