Combined Elevation of Temperature and CO2 Impacts the Production and Sugar Composition of Aphid Honeydew.

Honeydew is the keystone of many interactions between aphids and their predators, parasitoids, and mutualistic partners. Despite the crucial importance of honeydew in aphid-ant mutualism, very few studies have investigated the potential impacts of climate change on its production and composition. Here, we quantified changes in sugar compounds and the amount of honeydew droplets released by Aphis fabae reared on Vicia faba plants under elevated temperature and/or CO2 conditions. Following the combined elevation of these two abiotic factors, we found a significant increase in the fructose content of A. fabae honeydew, accompanied by nonsignificant trends of increase in total honeydew production and melezitose content. The environmental conditions tested in this study did not significantly impact the other honeydew sugar contents. The observed changes may be related to changes in phloem composition under elevated CO2 conditions as well as to increases in aphid metabolism and sap ingestion under elevated temperatures. Although limited, such changes in aphid honeydew may concurrently reinforce ant attendance and mutualism under elevated temperature and CO2 conditions. Finally, we discuss the enhancing and counteracting effects of climate change on other biological agents (gut microorganisms, predators, and parasitoids) that interact with aphids in a complex multitrophic system.

ASSESSING THE FORAGING BEHAVIOR OF AGRIOTES SORDIDUS WIREWORMS IN DUAL-CHOICE OLFACTOMETERS.

The different steps of the foraging process of wireworms (Coleoptera: Elateridae) would be better understood if accurate and holistic information regarding the role of plant-produced chemicals constituting their environment were available. Volatile organic compounds (VOC) play important roles in the interactions between plants and insects in many ecosystems, whether they take place aboveground or below-ground. The roles of VOC are still relatively unknown for wireworms, and deserve attention. Here, we performed three experimentations with barley roots as baits. In the two first, we assessed the effect of chopped roots and fungus infected roots on the orientation of wireworms. In the third experiment, the larvae were confronted to both healthy and fungus infected roots. We discuss the results in terms of suitability of the olfactometers we designed for the investigation of olfaction in wireworms, and we provide suggestions to improve their use.

Forensic entomology investigations from Doctor Marcel Leclercq (1924-2008): a review of cases from 1969 to 2005.

Dr. Marcel Leclercq was a pioneer in the field of forensic entomology. He has provided his knowledge of insect biology to many forensic cases, and most of them have found the way to publication. Most of the articles he has written were focused on individual cases, and despite the abundance of entomoforensic investigations he conducted, no synthesis has been published. This article summarizes 36 yr of forensic entomological investigations in temperate Europe, mainly in Belgium. Dr. Leclercq's work includes 132 entomological cases involving 141 human corpses found in various death scenes. Under certain conditions, insect specimens found at death scene can provide information on when (postmortem interval estimation), where and how a person died. More or less 100 insect species associated with a dead body have been identified by Dr. Leclercq.

Volatile organic compounds released by blowfly larvae and pupae: new perspectives in forensic entomology.

To evaluate postmortem intervals (PMIs), one should take into account the determined age of necrophagous flies present on the cadaver. However, PMI determination needs further improvement, and rapid and accurate approaches have therefore to be developed. While previous studies have focussed on insect cuticular hydrocarbons, here we explore the volatile profile released by larvae and pupae of Calliphora vicina Robineau-Desvoidy (Diptera: Calliphoridae). We monitored changes in volatile compounds daily, by headspace solid-phase microextraction, followed by gas chromatography-mass spectrometry. Branched and unbranched hydrocarbons, alcohols, esters and acids were identified, and the volatile profile was shown to vary, in both composition and quantity, with the age of the larva/pupa under investigation. We concluded, based on the analysis of the released volatile organic compounds, that it is possible to increase the accuracy of the estimated PMI, through improved estimation of the age of blowflies present on the cadaver.

Does Tribolium brevicornis cuticular chemistry deter cannibalism and predation of pupae?

The cuticular hydrocarbons of insects are species-specific and often function as semiochemicals. The activity of Tribolium brevicornis cuticular hydrocarbons as feeding deterrents that ostensibly function to prevent pupal cannibalism and predation was evaluated. The cuticular hydrocarbons of T. brevicornis pupae were characterized and flour disk bioassays conducted with individual and combined extract components incorporated into artificial diets on which Tribolium adults fed for six days. Feeding by T. brevicornis and T. castaneum on flour disks containing cuticular extracts of T. brevicornis pupae resulted in reduced consumption and weight loss relative to feeding on control flour disks. In both cases, feeding deterrence indices exceeded 80% suggesting that T. brevicornis cuticular hydrocarbons could function to deter cannibalism and predation of pupae by larvae and adult beetles. Sixteen different cuticular hydrocarbons were identified in T. brevicornis pupal extracts. Eight of the commercially available linear alkanes were tested individually in feeding trials with eight Tribolium species. One compound (C28) significantly reduced the amount of food consumed by three species compared to control disks, whereas the compounds C25, C26, and C27 elicited increased feeding in some species. Four other compounds had no effect on consumption for any species. When four hydrocarbon mixtures were tested for synergistic deterrence on T. brevicornis and T. castaneum, none significantly influenced consumption. Our results indicate that the cuticular chemistry of T. brevicornis pupae could serve to deter predation by conspecific and congeneric beetles.

Cadaveric volatile organic compounds released by decaying pig carcasses (Sus domesticus L.) in different biotopes.

Forensic entomology uses pig carcasses to surrogate human decomposition and to investigate the entomofaunal colonization. Insects communicate with their environment through the use of chemical mediators, which in the case of necrophagous insects, may consist in the cadaveric volatile organic compounds (VOCs) released by the corpse under decomposition. Previous studies have focused on cadaveric VOCs released from human corpses. Nevertheless, studies on human corpses are restricted for many reasons, including ethics. Forensic entomologists use pig as animal model but very few information are available about the decompositional VOCs released by a decaying pig carcass. We here tested a passive sampling technique, the Radiello diffusive sampler, to monitor the cadaveric VOCs released by decomposing pig carcasses in three biotopes (crop field, forest, urban site). A total of 104 chemical compounds, exclusively produced by the decompositional process, were identified by thermal desorption interfaced with gas chromatography and mass spectrometry (TDS-GC-MS). Ninety, 85 and 57 cadaveric VOCs were identified on pig carcasses laying on the agricultural site, the forest biotope and in the urban site, respectively. The main cadaveric VOCs are acids, cyclic hydrocarbons, oxygenated compounds, sulfur and nitrogen compounds. A better knowledge of the smell of death and their volatile constituents may have many applications in forensic sciences.

Does imidacloprid seed-treated maize have an impact on honey bee mortality?

Beekeepers suspected maize, Zea mays L., treated with imidacloprid to result in substantial loss of honey bee (Hymenoptera: Apidae) colonies in Belgium. The objective of this study was to investigate the potential impact of maize grown from imidacloprid-treated seeds on honey bee mortality. A survey of 16 apiaries was carried out, and all maize fields treated or not with imidacloprid were located within a radius of 3,000 m around the observed apiaries. Samples of honey, beeswax, and bees were collected in three colonies per apiary and analyzed for pesticide contain by liquid chromatography-tandem mass spectrometry and gas chromatography-tandem mass spectrometry. We first found a significant correlation between the number of colonies per apiary and the mortality rates in an apiary. In addition, this mortality rate was inversely correlated with the surface of maize fields treated and not with imidacloprid, suggesting that this pesticide do not interact with bees' fitness. Moreover, a very large number of our samples contained acaricides either prohibited or ineffective against Varroa destructor (Anderson & Trueman) (Acari: Varroidae), suggesting that the treatment methods used by the beekeepers to be inadequate for mite control. Our results support the hypothesis that imidacloprid seed-treated maize has no negative impact on honey bees.

Mothflies (Diptera: Psychodidae) in hospitals: a guide to their identification and methods for their control.

Repeated observation of "mothflies" at CHU Brugmann (Horta site hospital in Brussels) is not an isolated incident. Many public buildings have been infested by these Diptera of the Psychodidae Family. Although the species currently seen in Belgium is not a danger to human health, any infestation should be swiftly eradicated so as to limit the risks of a massive proliferation, source of hygiene problems and of potential bacterial dissemination. A good knowledge of adult and larval biology allows the potential sites of infestation to be quickly identified. The method to be envisaged to solve the problem will combine different approaches such as removing the risk factors (decomposing organic matter), monitoring egg-laying sites, applying caustic soda-based products and possibly treating with insecticide.

Emission of alarm pheromone in aphids: a non-contagious phenomenon.

In response to attack by natural enemies, most aphid species release an alarm pheromone that causes nearby conspecifics to cease feeding and disperse. The primary component of the alarm pheromone of most species studied is (E)-beta-farnesene. We recently demonstrated that the production and accumulation of (E)-beta-farnesene during development by juvenile aphids is stimulated by exposure to odor cues, most likely by (E)-beta-farnesene emitted by other colony members. Here, we tested whether the release of (E)-beta-farnesene can be triggered by exposure to the alarm pheromone of other individuals, thereby amplifying the signal. Such contagious emission might be adaptive under some conditions because the amount of (E)-beta-farnesene released by a single aphid may not be sufficient to alert an appropriate number of individuals of the colony to the presence of a potential threat. By using a push-pull headspace collection system, we quantified (E)-beta-farnesene released from Acyrthosiphon pisum aphids exposed to conspecific alarm signals. Typical avoidance behavior was observed following exposure to (E)-beta-farnesene (i.e., aphids ceased feeding and dropped from host-plant); however, no increase in alarm pheromone amount was detected, suggesting that contagious release of (E)-beta-farnesene does not occur.

What makes Episyrphus balteatus (Diptera: Syrphidae) oviposit on aphid infested tomato plants?

Under attack by insect pests, many plant species change their volatile chemical emissions to attract natural enemies. Most of the tomato (Lycopersicon sp., Solanaceae) varieties are subjected to infestation by molluscs and insects, including the generalist aphid Myzus persicae Sulzer (Homoptera, Aphididae). Episyrphus balteatus De Geer (Diptera: Syrphidae) is a generalist aphid predator that was here observed to lay eggs on M. persicae infested tomato but not on non-infested plants. In order to identify the volatile chemicals that guide the foraging and oviposition behaviour of E. balteatus, we collected and identified volatiles released in the headspace of both aphid infested and uninfested tomato plants by SPME-GC-MS. The identified chemicals were subsequently tested by electroantennography (EAG) on E. balteatus. Monoterpenes and sesquiterpenes were identified, the main volatile chemicals being beta-phellandrene, 2-carene, alpha-phellandrene, 3-carene and o-pinene. Electrical depolarizations were observed for each tested monoterpene, with optimal responses ranging from -0.2 to -0.8 mV. Episyrphus balteatus antennae showed dose-response relationships towards all the active chemicals. (E)-beta-farnesene, the main component of the aphid alarm pheromone, was the only active sesquiterpene, and is presumed to act as an oviposition stimulus for E. balteotus.

Electrophysiological and behavioral activity of secondary metabolites in the confused flour beetle, Tribolium confusum.

Several previous studies have addressed pheromone communication in various flour beetles (Coleoptera: Tenebrionidae), including the confused flour beetle, Tribolium confusum (du Val). Different stereoisomers of 4,8-dimethyldecanal (DMD) were reported as the only components of an aggregation pheromone, but the behavioral activity of DMD is low. In the present study, additional previously reported secondary metabolites (benzoquinones and hydrocarbons) were tested for electrophysiological activity (EAG) with both sexes of T. confusum. Two benzoquinones and three monoenic hydrocarbons elicited significant EAG activity from both male and female antennae. There was an elevated male EAG response (vs. the females) to two out of the three hydrocarbons and for both quinones. The EAG-active compounds were subsequently investigated for behavioral activity in a walking bioassay. Benzoquinones are considered toxic and have been assigned a function as alarm substances in flour beetles, but we found that methyl-1, 4-benzoquinone in intermediate concentrations was attractive to both male and female beetles and could therefore act as an aggregation pheromone component. Males were also attracted to ethyl-1,4-benzoquinone. The corresponding hydroquinones, presumed precursors of the benzoquinones, did not elicit any electrophysiological response and were not tested for behavioral activity. The unsaturated hydrocarbons (1-tetradecene, 1-pentadecene, and 1-hexadecene) elicited significant EAG responses from both male and female antennae and were also attractive in the behavioral assay. Our results show that several beetle-produced compounds, in addition to 4,8-dimethyldecanal, may be part of a complex pheromone system in flour beetles and play a role in mediating aggregation in T. confusum.

Plan-do-study-act cycles as an instrument for improvement of compliance with infection control measures in care of patients after cardiothoracic surgery.

The aim of this study was to determine whether compliance with infection control measures for the care of patients during and after cardiothoracic surgery could be improved by using 'plan-do-study-act' (PDSA) improvement cycles in a 715-bed university hospital. The endpoints of these cycles were indices of correct procedure based on infection control standards. The intervention consisted of instruction and training of nursing and medical staff on the use of PDSA cycles, feedback of the baseline measurements, and the use of posters in the proximity of the operating room (OR). At follow-up, overall compliance only improved in the room used by the perfusionists and the OR. After the follow-up period, monitoring revealed a drop in compliance in the OR, but improved compliance during vascular catheter care of patients with prolonged stay in the intensive care unit (ICU), and during wound care of patients on the nursing ward. The last series of monitoring showed that compliance with general infection control measures in the OR had improved again, and that compliance had remained satisfactory on the ward and in the ICU, with the exception of patients recently transferred to the ICU from the OR. The results show that by using PDSA cycles, compliance with infection control measures can improve significantly. However, repeated monitoring is necessary to ensure continued compliance.

Evaluation of hoverfly Episyrphus balteatus De Geer (Diptera: Syrphidae) oviposition behaviour toward aphid-infested plants using a leaf disc system.

Several aphidophagous beneficials such as parasitoids and predators are known to respond positively to aphid infested plants. Semiochemicals from the latter association play an important role in the foraging of predators in a tritrophic approach. In this work, three host plants infested with green peach aphid, Myzus persicae Sulzer were used to study the effect of prey density and aphid colony location on plant toward Episyrphus balteatus female. Their reproductive behaviour and efficiency (in terms of fecundity) were observed in net cages. Three kinds of experiments were performed using a disc leaf on agar diet in small Petri dishes under different conditions: 1) leaf disc of broad bean (Vicia faba) were infested with different aphid prey densities, 2) three host plants (Vicia faba, Solanum tuberosum, Solanum nigrum) infested with 3 different aphid prey densities and 3) three different heights of aphid colony location on V. faba plant infested with constant aphid density were also tested using leaf disc system. Aphid-free leaf discs were also used as control for predator behaviour observations. Oviposition rates of hoverfly on leaf disc system vary significantly with prey aphid densities. The means of eggs per laying were 0.9, 5.3, and 31.2 for 0, 10 and 100 aphid densities respectively. E. balteatus females were also able to evaluate and adjust oviposition rates according to different aphid prey densities/host plant. The 5 and 20 cm stakes were the most attractive heights of aphid colony location for the hoverfly oviposition. The means of eggs per laying were 16.7, 18.5 and 5.8 for 5, 20 and 40cm heights respectively. Our leaf disc system was found to be a practical and efficient way to assess chemical cues from aphids according to different conditions on the hoverfly reproductive behaviour.

Excretion and metabolism of desogestrel in healthy postmenopausal women.

The metabolism of desogestrel (13-ethyl-11-methylene-18,19-dinor-17alpha-pregn-4-en-20-yn-17-ol), a progestagen used in oral contraceptives and hormone replacement therapy, was studied in vivo after a single oral administration of 150 microg [14C]-labeled desogestrel and 30 microg ethinylestradiol under steady state conditions to healthy postmenopausal women. After this oral administration, desogestrel was extensively metabolized. The dosed radioactivity was predominantly ( approximately 60%) excreted via urine, while about 35% was excreted via the feces. Desogestrel was metabolized mainly at the C3-, C5-, C6- and C13-CH(2)CH(3) positions. At the C3-position, the 3-keto moiety was found and in addition, 3beta-hydroxy and 3alpha-hydroxy groups were observed in combination with a reduced Delta(4)-double bond (5alpha-H). Hydroxy groups were introduced at the C6- (6beta-OH), the C13-ethyl (C13-CH(2)CH(2)OH) and possibly the C15- (15alpha-OH) position of desogestrel. Conjugation of the 3alpha-hydroxy moiety with sulfonic acid and conjugation with glucuronic acid were also major metabolic routes found for desogestrel in postmenopausal women. The 3-keto metabolite of desogestrel (the biologically active metabolite) was the major compound present in plasma at least up to 24 h after administration of the radioactive dose. Species comparison of the metabolic routes of desogestrel after oral administration indicates that in rats and dogs desogestrel is also mainly metabolized at the C3-position, similar to what is now found for postmenopausal women. Most other metabolic routes of desogestrel were found to differ between species. Finally, major metabolic routes found in the present study in postmenopausal women are in line with outcome of previous in vitro metabolism studies with human liver tissue (microsomes and postmitochondrial liver fractions) and intestinal mucosa.

Assessing the necessity of hospital stay by means of the appropriateness evaluation protocol: how strong is the evidence to proceed?

OBJECTIVE: To review the Appropriateness Evaluation Protocol (AEP) with respect to assessing the necessity of hospital stay at the University Hospital of Maastricht. DESIGN: Literature search in Medline focusing on the validity, reliability and possibilities for intervention plus a description and the first results of pilot studies with a Dutch version of the Adult-Medical AEP (days of stay). SETTING: The University Hospital of Maastricht, a 700-bed university and regional hospital in the south of The Netherlands. MAIN OUTCOME MEASURES: Face, content, and convergent validity, and reliability in terms of overall or specific agreement and by kappa, of the Adult-Medical AEP when used by physicians and nurses. RESULTS: In comparison with other instruments, a comparatively good performance by the AEP has been reported in the literature. Literature review revealed limitations in the AEP as a general and truly valid and reliable instrument for assessing the necessity of hospital stay. In applying a Dutch version (azM-AEP) similar difficulties were encountered. CONCLUSION: Based on the literature review and our own findings, we conclude that the validity and reliability of the different versions of the AEP are not yet up to standard. Regarding the results of the interventions thus far, we do not encourage further use until additional improvements to both the instrument and the review conditions have been made. Perhaps a more disease-specific modulation and assessments based on computerized medical records could improve its applicability in clinical practice in general.

Patient satisfaction with clinical trial participation.

OBJECTIVE: To assess satisfaction of patients who participate in clinical trials requiring informed consent and to analyse factors determining patient satisfaction. SETTING: The survey took place in 26 clinical trials at the University Hospital Maastricht (azM), The Netherlands. DESIGN AND STUDY PARTICIPANTS: A personal interview and telephone questionnaire were used consecutively (n= 135; 135 out of 172=78.5% response rate) to measure patient's expectancies before starting the trial during the informed consent procedure and to evaluate aspects of trial participation. An additional control group of 34 patients was interviewed only by telephone (100% response). MEASURES: Satisfaction was assessed in two distinct ways: first, by measuring the patient's subjective evaluation of several aspects of trial participation; secondly, by comparing prior expectations and subsequent evaluations. Patient satisfaction was subdivided with respect to medical-technical, interpersonal and organizational aspects of trial participation. Changes in patient's health and illness perceptions were regarded as confounding factors in the relationship between satisfaction and its possible causes. RESULTS: Although patient satisfaction was quite high, dissatisfaction with aspects of trial participation became apparent when both prior expectations and subsequent evaluations were compared with each other. CONCLUSION: Prior expectations and general attitudes towards medical care and research before entering the trial have an impact on satisfaction with aspects of trial participation (10-20% explained variance). No linear relationship was found between perceived improvements in health and illness conditions and patient satisfaction with trial participation.

Determinants of patient participation in clinical studies requiring informed consent: why patients enter a clinical trial.

In a survey on 26 clinical trials we have studied the reasons why some patients choose to participate in clinical trials while others decline. Interviews were held with 198 adult patients, just after they had been asked by the trial-clinician to participate. We interviewed patients who were asked to participate in a clinical trial, including those who decided not to participate. The theoretical guidelines to explain participation were based on an extended form of the Health Belief Model. Patients being asked to participate in a clinical trial decide by making a personal balance account. This comprises the physical and emotional added value patients hope to gain from the trial treatment compared to the non-trial treatment, minus the risks they expect in the trial and minus the extra time they expect the trial will take. The extent they feel physically threatened by their illness will also influence their decision. Furthermore, this personal balance account was found to depend on patient opinion about medical care and care-givers in general and on how patients regard their illness. Relatively long-term patients show a slightly different motivation to participate in a clinical trial than short-term patients. In line with the Health Belief Model, motivational beliefs on the relevance to reducing the threat to the patient's health condition ('values') and the evaluations of the clinical trial the patient is approached for ('expectancy'), are relevant in explaining patient behavior. Moreover, specific evaluative frames of reference are relevant in patients faced with the choice to participate or not. Suggestions are made to improve insight into patient motivation during the informed consent procedure of clinical trials.