Oviposition behavior of the mirid Macrolophus pygmaeus under risk of intraguild predation and cannibalism

Zoophytophagous mirid species, that feed and develop either on prey or plant resources, are often found simultaneously on the same host. Hence, these species can engage in both intraguild predation and cannibalism, which can pose a threat to mirid eggs. Ovipositing females may respond to such risks of predation on their eggs by reducing the number of eggs laid or selecting safer oviposition sites. We tested the oviposition behaviour of Macrolophus pygmaeus (Rambur) (Hemiptera: Miridae) females under the risk of cannibalism by M. pygmaeus males and intraguild predation by Nesidiocoris tenuis (Reuter) males (Hemiptera: Miridae) under laboratory conditions. Intraguild predators and cannibals were introduced during or after the oviposition period. The number of eggs laid (using counts of newly hatched nymphs) and their proportion on each part of a tomato plant were both measured. The results reveal that only cannibalism by M. pygmaeus males after the period of oviposition significantly decreased the number of hatched eggs. Cannibalism thus represents a greater risk to mirid eggs than intraguild predation. The M. pygmaeus female responded to the presence of potential intraguild predators (or competitors) by decreasing the number of eggs laid in the upper leaves. The results suggest that M. pygmaeus females avoid competition by N. tenuis, by laying fewer eggs on upper leaves. Cannibalism could regulate zoophytophagous predator populations under prey scarcity conditions and minimize the risk of crop damage associated with those biological control agents.info:eu-repo/semantics/acceptedVersio

Characterization of a newly established aggregation of the invasive ladybeetle Harmonia axyridis and current status of the invader in Spain

The multicoloured Asian ladybeetle, Harmonia axyridis (Pallas), an invasive biocontrol agent introduced in North and South America, as well as in Europe for aphid control, drastically affected assemblages of native coccinellid species, local communities and people. Although the insect is common in several European countries and it was released in Spain for aphid control in 1995, no evidence of population establishment has been reported until 2011. In the present paper, 1) we summarize the records of the invasive ladybeetle in Spain and provide numerous new mentions, and 2) we follow for the first time an overwintering aggregation from autumn to spring and characterize some individual features which allow us to determine its phenology of the establishment and spreading. The results establish clearly that: 1) H. axyridis is (until now) restricted to Catalonia (NE Spain) but the invading process is in progress and the insect is able to occupy different habitats; 2) the ladybeetle overwinters successfully in Spain without significant natural mortality or parasitism; 3) the form succinea represents 73-81% of the overwintering individuals, and 4) the invasion takes probably its origin from Southern France. The potential impact of the invasion by H. axyridis in Spain is discussed

Harmonia axyridis: what will stop the invader?

Copyright © International Organization for Biological Control (IOBC) 2007.In recent years Harmonia axyridis (Pallas, 1773) (Coleoptera: Coccinellidae) has become a very popular insect among biological control practitioners and scientists, not only for its potential to be an efficient biological control agent but also because it is considered invasive. Individuals of this species were deliberately introduced into several countries for biological control of different arthropods pests. However the predator itself became an invasive species, affecting the dynamics and composition of several guilds through direct or indirect interactions with established species, including intraguild predation. In this paper we discuss the reasons why the species has a high invasiveness and what are the limits to invasion by this species. It is not clear if the invasiveness of the beetle is linked to its biological, ecological and behavioural abilities, or to other factors such as invasibility and interactions between the invaders, the noninvaders, and the habitat, which may in part explain the reasons of its success and help us to answer the question “what will stop the invader?” We also discuss the reason for the absence of the predator in the Azores islands. Despite the intentional introduction of H. axyridis in the Azores and the high number of individuals released, there are no records of this species in the wild, despite recent extensive sampling effort. In this paper we discuss the reasons for the apparent failure or the delay in establishment of the predator. One factor which may hamper the establishment of H. axyridis in some of the Azores islands is the absence of winter environmental conditions, mainly the temperature which is seldom lower than 12°C, essential for the induction of diapause. The lack of success in the establishment could be also related to functional diversity saturation, that is species saturation and competitive exclusion of H. axyridis by other previously established species may be operating

Costs and Benefits of Wax Production in the Larvae of the Ladybeetle Scymnus nubilus

BACKGROUND: Larvae of the minute aphidophagous Scymnus nubilus Mulsant (Coleoptera: Coccinellidae) are common predators in apple orchards, covered by a wax layer that might act as a defense mechanism against natural enemies. However, the costs and benefits of protection conferred by wax remain to be assessed. We tested the following hypothesis: there is a trade-off in wax producing ladybeetles between the protection conferred by wax cover and the physiological or behavioral costs associated with its production. We predict that: (1) wax production is an efficient defensive mechanism (against intraguild predation), (2) wax production is associated with detrimental physiological (growth, reproduction) or behavioral effects (behavioral compensation: increased biomass consumption). RESULTS: Tests were carried out in the laboratory with wax and waxless larvae of S. nubilus, with and without lacewing larvae of Chrysoperla agilis (Neuroptera: Chrysopidae) being used as a potential intraguild predator of the coccinellid. Waxless individuals were more susceptible to intraguild predation by lacewing larvae. Adults originating from waxless larvae were lighter than the ones originating from wax larvae, suggesting a metabolic cost resulting from a constant need of wax production. Body-weight gain and conversion efficiency were lower in waxless larvae. Biomass consumption was similar, showing that waxless larvae did not compensate for the physiological cost by eating more aphid biomass. CONCLUSION: The results indicate the potential existence of a trade-off between growth and protection associated with wax production.This work was financed by the research project "PRO-BIO: Profiling Reliable Organisms as Bioindicators: an integrated approach for island systems" financed by the FLAD (Fundação Luso-Americana para o Desenvolvimento) and partially funded by a grant from the Direção Regional dos Recursos Florestais of Secretaria Regional dos Recursos Naturais, Governo Regional dos Açores, Portugal to the research project: PICONIA: Controlo biológico de populações de pragas de plantas endémicas produzidas em viveiro.info:eu-repo/semantics/publishedVersio

Radial distribution of the carbonaceous nano-grains in the protoplanetary disk around HD 169142

HD 169142 is part of the class of (pre-)transitional protoplanetary disks showing multiple carbon nanodust spectroscopic signatures (aromatic, aliphatic) dominating the infrared spectrum. Precise constraints on the spatial distribution and properties of carbonaceous dust particles are essential to understanding the physics of the disk. The HD 169142 disk is seen almost face-on and thus offers a unique opportunity to study the dust radial evolution. We investigate the spatial distribution and properties of the carriers of several dust aromatic emission features in the disk across a broad spatial range (10-200 AU). We analysed imaging and spectroscopic observations in the 8-12 microns range from VLT/VISIR, as well as adaptive optics spectroscopic observations in the 3-4 microns range from VLT/NACO. The data probes the spatial evolution of the 3.3, 8.6, and 11.3 microns aromatic bands. To constrain the radial distribution of carbonaceous nano-grains, the observations were compared to models using The Heterogeneous dust Evolution Model for Interstellar Solids (THEMIS), integrated into the POLARIS radiative transfer code by calculating the thermal and stochastic heating of sub-micrometer dust grains. Our data show predominant nano-particle emission at all radii (resolution of about 0.1", 12 AU at 3 microns and 0.3", 35 AU at 10 microns) in the HD 169142 disk. This unambiguously shows that carbonaceous nano-grains dominate radiatively the infrared spectrum in most of the disk, as suggested by previous studies. In order to account for both VISIR and NACO emission maps, we show the need for aromatic particles distributed within the disk from the outermost regions to a radius of 20 AU, corresponding to the outer limit of the inner cavity derived from previous observations. In the inner cavity, these aromatic particles might be present but their abundance would then be significantly decreased.Comment: 11 pages, 8 figure

Contrasting Phenotypic Variability of Life-History Traits of Two Feral Populations of Macrolophus pygmaeus (Hemiptera: Miridae) under Two Alternative Diets

Tuta absoluta is a major pest attacking tomato crops. This invasive species emerged in Europe (Spain) in 2006, and 3 years later it spread to Portugal. In 2009/2010, it was recorded for the first time in the Azores archipelago. Macrolophus pygmaeus is a predator widely used as biological control agent against the tomato leaf miner. This study contrasted the life-history traits and population growth parameters of two feral populations of M. pygmaeus, one from Portugal mainland and one from the Azores archipelago. The predators were tested on single prey diet, either of Ephestia kuehniella eggs, a factitious prey used for mass rearing of mirids, or T. absoluta eggs. We predicted that populations would express differences in its phenotypic characteristics, with the Azorean population displaying low performance due to likely low genetic diversity, as expected for insular populations. Our results revealed the inexistence of phenotypic differences in several life history traits, such as immature developmental time, female longevity, males’ body weight and sex ratio. Contrary to our predictions, traits with direct impact on fitness, such as lifetime fertility (95.78 ± 14.23 vs. 61.38 ± 13.52 nymphs), explain better performances for the population of the Azores. Azorean M. pygmaeus females were larger, matured earlier and reproduced at a higher rate for longer periods, than mainland females. Therefore, population growth parameters show a positive advantage for the population of the Azores, fed on T. absoluta (time required for doubling the population Azores, Ek: 8.42 ± 0.50, Ta: 5.76 ± 0.31 and mainland, Ek: 10.88 ± 1.94, Ta: 12.07 ± 3.15). Biological performance of M. pygmaeus was similar when fed with T. absoluta or E. kuehniella that could be beneficial both to optimize mass production of the predator and biological control of the pest. Our results are discussed as well in a fundamental perspective, seeking if differences in biological performance can be explained by lower genetic diversity driven by geographic isolation.FUNDING: This study was financed by FEDER in 85% and by Azorean Public funds by 15% through Operational Program Azores 2020, under the project ECO2–TUTA (ACORES-01-0145-FEDER-000081). L.O. was funded by Portuguese national funds FCT under the project UIDP/05292/2020 and UIDB/05292/2020. E.F. was funded by Portuguese national funds FCT Umbert-ECO PTDC/ASPPLA/29110/2017. J.C.F. and E.F. received backing from Forest Research Centre (CEF) and Linking Landscape, Environment, Agriculture and Food (LEAF) research center, respectively, research units funded by Fundação para a Ciência e a Tecnologia (FCT), Portugal (UIDB/00239/2020 and UIDB/04129/2020, respectively), and both researchers from the Laboratory for Sustainable Land Use and Ecosystem Services–TERRA (LA/P/0092/2020).info:eu-repo/semantics/publishedVersio

n-3 Fatty acid intake from marine food products among Quebecers: comparison to worldwide recommendations

Objective: To quantify marine food product consumption and EPA + DHA intake among Quebecers, and to compare the results with the most recent recommendations. Design: Data were obtained from a representative cross-sectional telephone survey (June 2006). Intakes of marine food product species and EPA + DHA were estimated from a validated FFQ on the consumption of marine food products during the previous month. Prevalence of fish oil consumption in the last 6 months was also assessed. Setting: Province of Quebec (Canada). Subjects: A representative sample (n 1001) of adults in the province of Quebec. Of these, eight were excluded from the present analysis (n 993). Results: Mean and median EPA + DHA intakes for all participants were estimated to be 291 mg/d (sem 11) and 207 mg/d, respectively. 85·0 % (95 % CI 82·7, 87·3) of Quebecers had an EPA + DHA intake lower than 500 mg/d, which is the amount internationally recommended for the prevention of CVD. Mean and median DHA intakes among women of childbearing age (n 128, 18–34 years) were estimated to be 169 mg/d (sem 17) and 126 mg/d, respectively. Of these women, 27·7 % had a daily intake >200 mg DHA and 15·9 % had an intake >300 mg DHA. We noted that 13 % of Quebecers take ≥1 capsule of fish oil/d. Conclusions: Consumption of marine food products and EPA + DHA among Quebecers clearly appears to be lower than international recommendations. Since EPA + DHA confer health benefits and may reduce health costs, strategies to increase their consumption should be implemented to improve public health in Quebec

Bourdeilles – La grotte ornée des Bernoux

Lien Atlas (MCC) :http://atlas.patrimoines.culture.fr/atlas/trunk/index.php?ap_theme=DOM_2.01.02&ap_bbox=0.536;45.285;0.613;45.363 La reprise de l'étude du site des Bernoux en 2011 a enrichi et diversifié la connaissance du dispositif pariétal de la grotte. Ces découvertes nous ont conduit à initier un programme triennal d'étude décliné dans plusieurs directions. Il était essentiel, dans une approche globale du site, d'appréhender les entités graphiques dans leur complexité, le contexte arché..

Bourdeilles – La grotte ornée des Bernoux

Lien Atlas (MCC) :http://atlas.patrimoines.culture.fr/atlas/trunk/index.php?ap_theme=DOM_2.01.02&ap_bbox=0.536;45.285;0.613;45.363 La reprise de l'étude du site des Bernoux en 2011 a enrichi et diversifié la connaissance du dispositif pariétal de la grotte. Ces découvertes nous ont conduit à initier un programme triennal d'étude décliné dans plusieurs directions. Il était essentiel, dans une approche globale du site, d'appréhender les entités graphiques dans leur complexité, le contexte arché..