159 research outputs found

    Semiochemicals produced by fungal bark beetle symbiont Endoconidiophora rufipennis and the discovery of an anti-attractant for Ips typographus

    Get PDF
    Bark beetles vector symbiotic fungal species into their host trees during mass attacks. The symbiotic relationship with blue stain fungi of the Ascomycetes, including genera of Endoconidiophora (syn. = Ceratocystis), promotes successful establishment whereby the microbes help to overcome the host trees' defence and degrade toxic resins. This is the first study to evaluate both the volatile emissions from an insect-associated blue stain fungus over time and the insect response in a field trapping experiment. Volatile emissions from isolates of Endoconidiophora rufipennis (ER) were collected by solid-phase microextraction (SPME) and analysed by gas chromatography-mass spectroscopy (GC-MS) over a period of 30 days. This virulent North American fungus is closely related to E. polonica, a symbiotic fungus known from Eurasian spruce bark beetle Ips typographus.Nine volatiles were emitted by ER in substantial amounts: isoamyl acetate, sulcatone, 2-phenethyl acetate, geranyl acetone, geranyl acetate, citronellyl acetate, (R)- and (S)-sulcatol, and (R)-sulcatol acetate. A late peaking compound was geranyl acetone. In the field trapping experiment, three of the fungal volatiles (geranyl acetone, 2-phenethyl acetate and sulcatone) were tested in combination with a synthetic aggregation pheromone for I. typographus. Traps with geranyl acetone attracted lower numbers of I. typographus compared to traps with 2-phenethyl acetate, sulcatone or the pheromone alone as a control. The results showed that geranyl acetone acts as an anti-attractant and may act naturally on I. typographus as a cue from an associated fungus to signal an overexploited host

    Non-host volatile blend optimization for forest protection against the European Spruce Bark Beetle, Ips typographus

    Get PDF
    Conifer feeding bark beetles (Coleoptera, Curculionidae, Scolytinae) pose a serious economic threat to forest production. Volatiles released by non-host angiosperm plants (so called non-host volatiles, NHV) have been shown to reduce the risk of attack by many bark beetle species, including the European spruce bark beetle, Ips typographus. However, the most active blend for I. typographus, containing three green leaf volatiles (GLVs) in addition to the key compounds trans-conophthorin (tC) and verbenone, has been considered too expensive for use in large-scale management. To lower the cost and improve the applicability of NHV, we aim to simplify the blend without compromising its anti-attractant potency. Since the key compound tC is expensive in pure form, we also tested a crude version: technical grade trans-conophthorin (T-tC). In another attempt to find a more cost effective substitute for tC, we evaluated a more readily synthesized analog: dehydroconophthorin (DHC). Our results showed that 1-hexanol alone could replace the three-component GLV blend containing 1- hexanol, (3Z)-hexen-1-ol, and (2E)-hexen-1-ol. Furthermore, the release rate of tC could be reduced from 5 mg/day to 0.5 mg/day in a blend with 1-hexanol and (–)-verbenone without compromising the anti-attractant activity. We further show that T-tC was comparable with tC, whereas DHC was a less effective anti-attractant. DHC also elicited weaker physiological responses in the tC-responding olfactory receptor neuron class, providing a likely mechanistic explanation for its weaker anti-attractive effect. Our results suggest a blend consisting of (–)-verbenone, 1-hexanol and technical transconophthorin as a cost-efficient anti-attractant for forest protection against I. typographus

    Linguistic foundations of heritage language development from the perspective of romance languages in Germany

    Get PDF
    This paper discusses the role of different factors determining the linguistic competence of heritage speakers (HSs) based on examples from speakers who speak a Romance language (French, Italian, Portuguese, or Spanish) as heritage language (HL) and German as the environmental language. Since the relative amount of contact with the HL and the environmental language may vary during the acquisition process, the role of language dominance (in terms of relative language proficiency) is of particular interest for HL development. In addition to dominance (and related to it), cross-linguistic influence (CLI) may have an influence on the outcome of HL acquisition. Finally, quality and quantity of input also determine HL acquisition and will be discussed in connection with heritage language education.info:eu-repo/semantics/publishedVersio

    Mosquito Feeding Affects Larval Behaviour and Development in a Moth

    Get PDF
    Organisms are attacked by different natural enemies present in their habitat. While enemies such as parasitoids and predators will kill their hosts/preys when they successfully attack them, enemies such as micropredators will not entirely consume their prey. However, they can still have important consequences on the performance and ecology of the prey, such as reduced growth, increased emigration, disease transmission

    Behavior in a stressful situation, personality factors, and disease severity in patients with acute myocardial infarction: baseline findings from the prospective cohort study SECAMI (The Secondary Prevention and Compliance following Acute Myocardial Infarction-study)

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Psychosocial stress has been identified as a risk factor in association with cardiovascular disease but less attention has been paid to heterogeneity in vulnerability to stress. The serial Color Word Test (CWT) measures adaptation to a stressful situation and it can be used to identify individuals that are vulnerable to stress. Prospective studies have shown that individuals with a maladaptive behavior in this test are exposed to an increased risk of future cardiovascular events. The aim of the present study was to investigate whether maladaptive behavior in the serial CWT alone or in combination with any specific personality dimension was associated with severity of myocardial infarction (MI).</p> <p>Methods</p> <p>MI-patients (n = 147) completed the test and filled in a personality questionnaire in close proximity to the acute event. The results were analyzed in association with four indicators of severity: maximum levels above median of the cardiac biomarkers troponin I and creatine kinase-MB (CKMB), Q-wave infarctions, and a left ventricular ejection fraction (LVEF) ≀ 50%.</p> <p>Results</p> <p>Maladaptive behavior in the serial CWT together with low scores on extraversion were associated with maximum levels above median of cardiac troponin I (OR 2.97, CI 1.08-8.20, p = 0.04) and CKMB (OR 3.33, CI 1.12-9.93, p = 0.03). No associations were found between the combination maladaptive behavior and low scores on extraversion and Q-wave infarctions or a decreased LVEF.</p> <p>Conclusions</p> <p>Maladaptive behavior in combination with low scores on extraversion is associated with higher cardiac biomarker levels following an MI. The serial CWT and personality questionnaires could be used to identify individuals vulnerable to the hazardous effects of stress and thereby are exposed to an increased risk of a more severe infarction.</p

    Pheromones and Other Semiochemicals for Monitoring Rare and Endangered Species

    Get PDF
    As global biodiversity declines, biodiversity and conservation have become ever more important research topics. Research in chemical ecology for conservation purposes has not adapted to address this need. During the last 10-15 years, only a few insect pheromones have been developed for biodiversity and conservation studies, including the identification and application of pheromones specifically for population monitoring. These investigations, supplemented with our knowledge from decades of studying pest insects, demonstrate that monitoring with pheromones and other semiochemicals can be applied widely for conservation of rare and threatened insects. Here, I summarize ongoing conservation research, and outline potential applications of chemical ecology and pheromone-based monitoring to studies of insect biodiversity and conservation research. Such applications include monitoring of insect population dynamics and distribution changes, including delineation of current ranges, the tracking of range expansions and contractions, and determination of their underlying causes. Sensitive and selective monitoring systems can further elucidate the importance of insect dispersal and landscape movements for conservation. Pheromone-based monitoring of indicator species will also be useful in identifying biodiversity hotspots, and in characterizing general changes in biodiversity in response to landscape, climatic, or other environmental changes
    • 

    corecore