578 results on '"Harvey, J.A."'
Search Results
2. Scientists' warning on climate change and insects
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Harvey, J.A., Tougeron, K., Gols, R., Heinen, R., Hallmann, C., Verberk, W.C.E.P., Wagner, D.L., Weisser, W.W., Wetzel, W.C., Woods, H.A., Wyckhuys, K.A.G., Chown, S.L., Harvey, J.A., Tougeron, K., Gols, R., Heinen, R., Hallmann, C., Verberk, W.C.E.P., Wagner, D.L., Weisser, W.W., Wetzel, W.C., Woods, H.A., Wyckhuys, K.A.G., and Chown, S.L.
- Abstract
05 december 2022, Contains fulltext : 286471.pdf (Publisher’s version ) (Open Access)
- Published
- 2023
3. code from: Soil legacy effects of plants and drought on aboveground insects in native and range-expanding plant communities
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Li, K., Veen, G.F., ten Hooven, Freddy, Harvey, J.A., van der Putten, W.H., Li, K., Veen, G.F., ten Hooven, Freddy, Harvey, J.A., and van der Putten, W.H.
- Abstract
Soils contain biotic and abiotic legacies of previous conditions that may influence plant community biomass and associated aboveground biodiversity. However, little is known about the relative strengths and interactions of the various belowground legacies on aboveground plant–insect interactions. We used an outdoor mesocosm experiment to investigate the belowground legacy effects of range-expanding versus native plants, extreme drought and their interactions on plants, aphids and pollinators. We show that plant biomass was influenced more strongly by the previous plant community than by the previous summer drought. Plant communities consisted of four congeneric pairs of natives and range expanders, and their responses were not unanimous. Legacy effects affected the abundance of aphids more strongly than pollinators. We conclude that legacies can be contained as soil ‘memories’ that influence aboveground plant community interactions in the next growing season. These soil-borne ‘memories’ can be altered by climate warming-induced plant range shifts and extreme drought.
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- 2023
4. code from: The role of male body size in mating success and male–male competition in a false widow spider
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Dong, Yuting, Harvey, J.A., Steegh, Robin, Gols, Rieta, Rowe, M., Dong, Yuting, Harvey, J.A., Steegh, Robin, Gols, Rieta, and Rowe, M.
- Abstract
In many animals, body size is correlated with reproductive success. Selection sometimes generates striking differences in body size between males and females (i.e. sexual size dimorphism, SSD). SSD is common in spiders (Araneae), and is typically explained by selection for larger, more fecund females and rapidly maturing, and consequently smaller, males. Within a species males and females also often vary in body size. In the false widow spider, Steatoda grossa, females are larger than males and males trade body size for rapid development and early maturation. Moreover, males vary considerably in body size, suggesting that under certain conditions there may be advantages to large size. Here, we tested the role of male body size on mating success under noncompetitive and competitive mating conditions (i.e. male–male competition) in S. grossa. We found that body size did not influence mating success or copulation duration under noncompetitive conditions, but that larger males were more successful at obtaining access to females under competitive mating conditions. Additionally, we found that total copulation duration was significantly lower when a rival male was present. Our results show a large male advantage under male–male competition, which we suggest may contribute to the high variation in male body size observed in S. grossa. We further suggest that the reduced copulation duration observed under competitive mating conditions may have potential ramifications for male and female reproductive success and we discuss how patterns of selection acting on male body size might limit the extent of SSD in this species.
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- 2023
5. Mechanistic analysis by NMR spectroscopy: A users guide
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Yael Ben-Tal, Patrick J. Boaler, Harvey J.A. Dale, Ruth E. Dooley, Nicole A. Fohn, Yuan Gao, Andrés García-Domínguez, Katie M. Grant, Andrew M.R. Hall, Hannah L.D. Hayes, Maciej M. Kucharski, Ran Wei, and Guy C. Lloyd-Jones
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Kinetics ,Nuclear and High Energy Physics ,Magnetic Resonance Spectroscopy ,Isotopes ,Biochemistry ,Spectroscopy ,Analytical Chemistry - Abstract
A ‘principles and practice’ tutorial-style review of the application of solution-phase NMR in the analysis of the mechanisms of homogeneous organic and organometallic reactions and processes. This review of 345 references summarises why solution-phase NMR spectroscopy is uniquely effective in such studies, allowing non-destructive, quantitative analysis of the wide range of nuclei common to organic and organometallic reactions, providing exquisite structural detail, and using instrumentation that is routinely available in most chemistry research facilities. The review is in two parts. The first comprises an introduction to general techniques and equipment, and guidelines for their selection and application. Topics include practical aspects of the reaction itself, reaction monitoring techniques, NMR data acquisition and processing, analysis of temporal concentration data, NMR titrations, DOSY, and the use of isotopes. The second part comprises a series of 15 'Case Studies', each selected to illustrate specific techniques and approaches discussed in the first part, including in situ NMR (1/2H, 10/11B, 13C, 15N, 19F, 29Si, 31P), kinetic and equilibrium isotope effects, isotope entrainment, isotope shifts, isotopes at natural abundance, scalar coupling, kinetic analysis (VTNA, RPKA, simulation, steady-state), stopped-flow NMR, flow NMR, rapid injection NMR, pure shift NMR, dynamic nuclear polarisation, 1H/19F DOSY NMR, and in situ illumination-NMR
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- 2022
6. Enhancing the predictability of ecology in a changing world
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Musters, C.J.M., DeAngelis, D.L., Harvey, J.A., Mooij, W.M., Bodegom, P.M. van, and Snoo, G.R. de
- Abstract
Ecology is usually very good in making descriptive explanations of what is observed, but is often unable to make predictions of the response of ecosystems to change. This has implications in a human-dominated world where a suite of anthropogenic stresses are threatening the resilience and functioning of ecosystems that sustain mankind through a range of critical regulating and supporting services. In ecosystems, cause-and-eect relationships are dicult to elucidate because of complex networks of negative and positive feedbacks. Therefore, being able to eectively predict when and where ecosystems could pass into dierent (and potentially unstable) new states is vitally important under rapid global change. Here, we argue that such better predictions may be reached if we focus on organisms instead of species, because organisms are the principal biotic agents in ecosystems that react directly on changes in their environment. Several studies show that changes in ecosystems may be accurately described as the result of changes in organisms and their interactions. Organism-based theories are available that are simple and derived fromfirst principles, but allow many predictions. Of these we discuss Trait-based Ecology, Agent Based Models, and Maximum Entropy Theory of Ecology and show that together they form a logical sequence of approaches that allow organism-based studies of ecological communities. Combining and extending them makes it possible to predict the spatiotemporal distribution of groups of organisms in terms of how metabolic energy is distributed over areas, time, and resources. We expect that this “Organism-based Ecology” (OE) ultimately will improve our ability to predict ecosystem dynamics.
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- 2023
7. Prey availability affects developmental trade-offs and sexual-size dimorphism in the false widow spider, Steatoda grossa
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Harvey, J.A. and Harvey, J.A.
- Abstract
In many spiders, females are significantly larger than males. Several theories have been postulated to explain sexual size dimorphism (SSD), including differential predation risks experienced by each sex early in life (including female cannibalism of males), male-male competition, and the more costly production of eggs than sperm. However, there is considerable intraspecific variation in the relative size of males and females that is reflected in trade-offs on traits such as growth rate and body size. When SSD favors female size, the body mass ratios between the smallest and largest males is expected to be much greater than in females. Here, growth trajectories and body masses of the false widow spider, Steatoda grossa, were compared in male and female spiders fed continually or intermittently. Males provided with unlimited prey (fruit flies and house crickets) took about 15 weeks to attain full size and sexual maturity and grew to a mean of 25 mg. By contrast, males fed only once every three weeks took approximately 6 weeks longer to reach maturity but were only about half as large (mean 13 mg) as males fed constantly. Females fed intermittently took almost twice as long (45 weeks versus 24 weeks) as constantly-fed females to reach maturity, but were almost 90% as large when fully grown. These results reveal that, although both sexes trade-off development time and body size to achieve the optimal phenotype, rapid development is more important than larger body size in males whereas the opposite is true in females. This finding supports life-history theory underpinning sexual-size dimorphism in some spider lineages.
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- 2022
8. Extrinsic Inter- and Intraspecific Competition in Parasitoid Wasps
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Ode, Paul J., Vyas, Dhaval K., Harvey, J.A., Ode, Paul J., Vyas, Dhaval K., and Harvey, J.A.
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The diverse ecology of parasitoids is shaped by extrinsic competition, i.e., exploitative or interference competition among adult females and males for hosts and mates. Adult females use an array of morphological, chemical, and behavioral mechanisms to engage in competition that may be either intra- or interspecific. Weaker competitors are often excluded or, if they persist, use alternate host habitats, host developmental stages, or host species. Competition among adult males for mates is almost exclusively intraspecific and involves visual displays, chemical signals, and even physical combat. Extrinsic competition influences community structure through its role in competitive displacement and apparent competition. Finally, anthropogenic changes such as habitat loss and fragmentation, invasive species, pollutants, and climate change result in phenological mismatches and range expansions within host-parasitoid communities with consequent changes to the strength of competitive interactions. Such changes have important ramifications not only for the success of managed agroecosystems, but also for natural ecosystem functioning.
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- 2022
9. Evaluating the effects of the invasive cane toad (Rhinella marina) on island biodiversity, focusing on the Philippines
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Harvey, J.A., Ambavane, Priyanka, Williamson, Mark, Diesmos, Arvin, Harvey, J.A., Ambavane, Priyanka, Williamson, Mark, and Diesmos, Arvin
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- 2022
10. Data underlying the publication 'Within-patch and edge microclimates vary over a growing season and are amplified during a heatwave: Consequences for ectothermic insects'
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Ojeda-Prieto, L.M., Gols, R., Harvey, J.A., Li, K., van der Putten, W.H., Ojeda-Prieto, L.M., Gols, R., Harvey, J.A., Li, K., and van der Putten, W.H.
- Abstract
Temperatures were measured in a small-scale mesocosm (1 m2) experiment during an 8-week period in the summer of 2020, in the Netherlands. The period included a heatwave. Forty mesocosms, each devided in 4 quadrants, were planted with forbs. Temperatures were measured three time a week, during the warmest part of the day, i.e. between 1400 and 1500 h. using an infrared thermometer gun (BOSCH Thermodetector PTD1). Temperatures were mearured near the soil surface at the edge of the mesocosm, near the soil surface between two quadrants in each mesocosm. Within each mesocosm, as well as within the plant canopy. In addition the ambient temperature was measured., Temperatures were measured in a small-scale mesocosm (1 m2) experiment during an 8-week period in the summer of 2020, in the Netherlands. The period included a heatwave. Forty mesocosms, each devided in 4 quadrants, were planted with forbs. Temperatures were measured three time a week, during the warmest part of the day, i.e. between 1400 and 1500 h. using an infrared thermometer gun (BOSCH Thermodetector PTD1). Temperatures were mearured near the soil surface at the edge of the mesocosm, near the soil surface between two quadrants in each mesocosm. Within each mesocosm, as well as within the plant canopy. In addition the ambient temperature was measured.
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- 2022
11. Ecological Fitting and Novel Species Interactions in Nature
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Malcicka, M., primary and Harvey, J.A., additional
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- 2016
- Full Text
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12. LB752 A cross sectional survey of skin cancer knowledge, attitudes, and sun care practices in an underserved Phoenix population
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Besch-Stokes, J., primary, Harvey, J.A., additional, Brumfiel, C.M., additional, Patel, M.H., additional, Montoya, J., additional, Severson, K., additional, Cumsky, H., additional, Buras, M.R., additional, González Fagoaga, J., additional, and Mangold, A., additional
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- 2021
- Full Text
- View/download PDF
13. Within-patch and edge microclimates vary over a growing season and are amplified during a heatwave: Consequences for ectothermic insects
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Gols, R., primary, Ojeda-Prieto, L.M., additional, Li, K., additional, van der Putten, W.H., additional, and Harvey, J.A., additional
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- 2021
- Full Text
- View/download PDF
14. Reflections on the SARS-Covid-2 pandemic after one year: predictable, preventable but inevitable: an ecologist’s perspective
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Harvey, J.A. and Terrestrial Ecology (TE)
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NIOO ,Plan_S-Compliant_NO - Published
- 2021
15. Within-patch and edge microclimates vary over a growing season and are amplified during a heatwave : Consequences for ectothermic insects
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Gols, R., Ojeda-Prieto, L.M., Li, K., van der Putten, W.H., Harvey, J.A., Gols, R., Ojeda-Prieto, L.M., Li, K., van der Putten, W.H., and Harvey, J.A.
- Abstract
Embedded in longer term warming are extreme climatic events such as heatwaves and droughts that are increasing in frequency, duration and intensity. Changes in climate attributes such as temperature are often measured over larger spatial scales, whereas environmental conditions to which many small ectothermic arthropods are exposed are largely determined by small-scale local conditions. Exposed edges of plant patches often exhibit significant short-term (daily) variation to abiotic factors due to wind exposure and sun radiation. By contrast, within plant patches, abiotic conditions are generally much more stable and thus less variable. Over an eight-week period in the summer of 2020, including an actual heatwave, we measured small-scale (1 m2) temperature variation in patches of forbs in experimental mesocosms. We found that soil surface temperatures at the edge of the mesocosms were more variable than those within mesocosms. Drought treatment two years earlier, amplified this effect but only at the edges of the mesocosms. Within a plant patch both at the soil surface and within the canopy, the temperature was always lower than the ambient air temperature. The temperature of the soil surface at the edge of a patch may exceed the ambient air temperature when ambient air temperatures rise above 23 °C. This effect progressively increased with ambient temperature. We discuss how microscale-variation in temperature may affect small ectotherms such as insects that have limited ability to thermoregulate, in particular under conditions of extreme heat.
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- 2021
16. Divergent composition but similar function of soil food webs of individual plants: plant species and community effects
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Bezemer, T.M., Fountain, M.T., Barea, J.M., Christensen, S., Dekker, S.C., Duyts, H., Van Hal, R., Harvey, J.A., Hedlund, K., Maraun, M., Mikola, J., Mladenov, A.G., Robin, C., De Ruiter, P.C., Scheu, S., Setala, H., Smilauer, P., and Van Der Putten, W.H.
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Plant communities -- Research ,Plant nematodes -- Research ,Plant-soil relationships -- Research ,Biological sciences ,Environmental issues - Abstract
Soils are extremely rich in biodiversity, and soil organisms play pivotal roles in supporting terrestrial life, but the role that individual plants and plant communities play in influencing the diversity and functioning of soil food webs remains highly debated. Plants, as primary producers and providers of resources to the soil food web, are of vital importance for the composition, structure, and functioning of soil communities. However, whether natural soil food webs that are completely open to immigration and emigration differ underneath individual plants remains unknown. In a biodiversity restoration experiment we first compared the soil nematode communities of 228 individual plants belonging to eight herbaceous species. We included grass, leguminous, and non-leguminous species. Each individual plant grew intermingled with other species, but all plant species had a different nematode community. Moreover, nematode communities were more similar when plant individuals were growing in the same as compared to different plant communities, and these effects were most apparent for the groups of bacterivorous, carnivorous, and omnivorous nematodes. Subsequently, we analyzed the composition, structure, and functioning of the complete soil food webs of 58 individual plants, belonging to two of the plant species, Lotus corniculatus (Fabaceae) and Plantago lanceolata (Plantaginaceae). We isolated and identified more than 150 taxa/groups of soil organisms. The soil community composition and structure of the entire food webs were influenced both by the species identity of the plant individual and the surrounding plant community. Unexpectedly, plant identity had the strongest effects on decomposing soil organisms, widely believed to be generalist feeders. In contrast, quantitative food web modeling showed that the composition of the plant community influenced nitrogen mineralization under individual plants, but that plant species identity did not affect nitrogen or carbon mineralization or food web stability. Hence, the composition and structure of entire soil food webs vary at the scale of individual plants and are strongly influenced by the species identity of the plant. However, the ecosystem functions these food webs provide are determined by the identity of the entire plant community. Key words: biodiversity; ecosystem function; food web composition; food web model; Lotus corniculatus; macrofauna; mesofauna; microfauna: Plantago lanceolata; soil biota.
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- 2010
17. Tolerance of Brassica nigra to Pieris brassicae herbivory
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Blatt, S.E., Smallegange, R.C., Hess, L., Harvey, J.A., Dicke, M., and van Loon, J.J.A.
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Mustard -- Physiological aspects ,Butterflies -- Environmental aspects ,Biological sciences - Abstract
Abstract: Black mustard, Brassica nigra (L.) Koch, is a wild annual species found throughout Europe and fed on by larvae of the large cabbage-white butterfly, Pieris brassicae L. We examined [...]
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- 2008
18. Range-expansion in processionary moths and biological control
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De Boer, J.G., Harvey, J.A., De Boer, J.G., and Harvey, J.A.
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Global climate change is resulting in a wide range of biotic responses, including changes in diel activity and seasonal phenology patterns, range shifts polewards in each hemisphere and/or to higher elevations, and altered intensity and frequency of interactions between species in ecosystems. Oak (Thaumetopoea processionea) and pine (T. pityocampa) processionary moths (hereafter OPM and PPM, respectively) are thermophilic species that are native to central and southern Europe. The larvae of both species are gregarious and produce large silken ‘nests’ that they use to congregate when not feeding. During outbreaks, processionary caterpillars are capable of stripping foliage from their food plants (oak and pine trees), generating considerable economic damage. Moreover, the third to last instar caterpillars of both species produce copious hairs as a means of defence against natural enemies, including both vertebrate and invertebrate predators, and parasitoids. These hairs contain the toxin thaumetopoein that causes strong allergic reactions when it comes into contact with human skin or other membranes. In response to a warming climate, PPM is expanding its range northwards, while OPM outbreaks are increasing in frequency and intensity, particularly in northern Germany, the Netherlands, and southern U.K., where it was either absent or rare previously. Here, we discuss how warming and escape from co-evolved natural enemies has benefitted both species, and suggest possible strategies for biological control. View Full-Text. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
- Published
- 2020
19. Exogenous application of plant hormones in the field alters aboveground plant–insect responses and belowground nutrient availability, but does not lead to differences in plant–soil feedbacks
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Heinen, R., Steinauer, K., De Long, J., Jongen, R., Biere, Arjen, Harvey, J.A., Bezemer, T.M., Heinen, R., Steinauer, K., De Long, J., Jongen, R., Biere, Arjen, Harvey, J.A., and Bezemer, T.M.
- Abstract
Plant–soil feedbacks of plants that are exposed to herbivory have been shown to differ from those of plants that are not exposed to herbivores. Likely, this process is mediated by jasmonic acid (JA) and salicylic acid (SA) defense pathways, which are induced by aboveground herbivory. Furthermore, exogenous application of these phytohormones to plants alters belowground communities, but whether this changes plant–soil feedbacks in natural systems is unknown. We applied exogenous sprays of JA and SA individually and in combination to field plots in a restored grassland. Control plots were sprayed with demineralized water. After three repeated application rounds, we transplanted seedlings of the plant–soil feedback model plant Jacobaea vulgaris as phytometer plants to test the effects of potential phytohormone-mediated changes in the soil, on plant performance during the response phase. We further measured how exogenous application of phytohormones altered plant-related ecosystem characteristics (plot-level); soil chemistry, plot productivity, insect communities and predation. Biomass of the phytometer plants only co-varied with plot productivity, but was not influenced by phytohormone applications. However, we did observe compound-specific effects of SA application on insect communities, most notably on parasitoid attraction, and of JA application on soil nitrogen levels. Although we did not find effects on plant–soil feedbacks, the effects of exogenous application of phytohormones did alter other ecosystem-level processes related to soil nutrient cycling, which may lead to legacy effects in the longer term. Furthermore, exogenous application of phytohormones led to altered attraction of specific insect groups.
- Published
- 2020
20. The ecological role of bacterial seed endophytes associated with wild cabbage in the United Kingdom
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Tyc, Olaf, Putra, Rocky, Gols, Rieta, Harvey, J.A., Garbeva, Paolina, Tyc, Olaf, Putra, Rocky, Gols, Rieta, Harvey, J.A., and Garbeva, Paolina
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- 2020
21. New neutron cross-section measurements at ORELA and their application in nuclear criticality calculations
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Guber, K.H., Leal, L.C., Sayer, R.O., Koehler, P.E., Valentine, T.E., Derrien, H., and Harvey, J.A.
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- 2005
- Full Text
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22. Klimaatverandering en ijsberenblogs revisited: het belang van wetenschappers aan het woord
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de Jong, Perro, Rienks, Froukje, Harvey, J.A., de Jong, Perro, Rienks, Froukje, and Harvey, J.A.
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- 2019
23. Spatial and temporal diversity in hyperparasitoid communities of Cotesia glomerata on garlic mustard, Alliaria petiolata
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Heinen, R., Harvey, J.A., Heinen, R., and Harvey, J.A.
- Abstract
1. Interactions between two trophic levels can be very intimate, often making species dependent on each other, something that increases with specialisation. Some specialised multivoltine herbivores may depend on multiple plant species for their survival over the course of a growing season, especially if their food plants are short‐lived and grow at different times. Later generations may exploit different plant species from those exploited by previous generations. 2. Multivoltine parasitoids as well as their natural enemies must also find their hosts on different food plants in different habitats across the season. Secondary hyperparasitoid communities have been studied on cocoons of the primary parasitoid, Cotesia glomerata (Hymenoptera: Braconidae), on black mustard (Brassica nigra) – a major food plant of its host, the large cabbage white (Pieris brassicae) – which grows in mid‐summer. 3. Here, hyperparasitoid communities on C. glomerata pupal clusters were studied on an early‐season host, garlic mustard, Alliaria petiolata, over ‘time’ (one season, April–July) in six closely located ‘populations’ (c. 2 km apart), and within two different ‘areas’ at greater separation (c. 100 km apart). At the plant level, spatial effects of pupal ‘location’ (canopy or bottom) on the plant were tested. 4. Although large‐scale separation (area) did not influence hyperparasitism, sampling time and small‐scale separation (population) affected hyperparasitism levels and composition of hyperparasitoid communities. Location on the plant strongly increased proportions of winged species in the canopy and proportions of wingless species in bottom‐located pupae. 5. These results show that hyperparasitism varies considerably at the local level, but that differences in hyperparasitoid communities do not increase with spatial distance.
- Published
- 2019
24. Data from: Differential effects of climate warming on reproduction and functional responses on insects in the fourth trophic level
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Chen, Cong, Gols, R., Biere, Arjen, Harvey, J.A., Chen, Cong, Gols, R., Biere, Arjen, and Harvey, J.A.
- Abstract
Understanding effects of Anthropogenic Global Warming (AGW) on species interactions is essential for predicting community responses to climate change. However, while effects of AGW on resource-consumer interactions at the first- and second trophic level have been well studied, little is known about effects on interactions at higher trophic levels at the terminal end of food chains (e.g. in the third and fourth trophic levels). 2. Here, we examined the effects of temperature variability by simulating heatwaves on functional responses of two species at the fourth trophic level (hyperparasitoids) that parasitize host species at the third trophic level (parasitoid cocoons). 3. We found that host cocoons developed faster under simulated heatwave conditions, decreasing the temporal window of susceptibility of the host cocoons to parasitism by the two hyperparasitoids, and consequently parasitism declined with temperature. However the effects of a simulated heatwave markedly differed among the two hyperparasitoid species; temperature and host quality had a much stronger effect on early reproduction in the less fecund hyperparasitoid Gelis agilis, than in the more fecund species Acrolyta nens. 4. Our results suggest that exposure to heatwaves, which are expected to increase in frequency, will affect the ability of species at higher trophic levels to exploit transient resources whose suitability is temperature-dependent. In turn, the observed effects of AGW on the functional responses of the hyperparasitoids may disrupt trophic interactions and have profound impact on population dynamics and ecological processes.
- Published
- 2019
25. Fast neutron-induced changes in net impurity concentration of high-resistivity silicon
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Tsveybak, I., Bugg, W., Harvey, J.A., and Walter, J.
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Electric resistance -- Research ,Silicon -- Electric properties ,Detectors -- Testing ,Business ,Electronics ,Electronics and electrical industries - Abstract
Resistivity changes produced by 1 Mev neutron irradiation at room temperature have been measured in float-zone grown n and p-type silicon with initial resistivities ranging from 1.8 to 100 k ohms cm. Observed changes are discussed in terms of net electrically active impurity concentration. A model is presented which postulates escape of Si self-interstitials and vacancies from damage clusters and their subsequent interaction with impurities and other pre-existing defects in the lattice. These interactions lead to transfer of B and P from electrically active substitutional configurations into electrically inactive positions (B(sub i), P(sub i), and E-center), resulting in changes of net electrically active impurity concentration. The changes in spatial distribution of resistivity are discussed, and the experimental data are fit by theoretical curves. Differences in the behavior of n-type and p-type material are explained on the basis of a faster removal of substitutional P and a more nonuniform spatial distribution of the original P concentration.
- Published
- 1992
26. Effects of soil organisms on aboveground plant-insect interactions in the field: patterns, mechanisms and the role of methodology
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Heinen, R., Biere, A., Harvey, J.A., Bezemer, T.M., Heinen, R., Biere, A., Harvey, J.A., and Bezemer, T.M.
- Abstract
Soil biota-plant interactions play a dominant role in terrestrial ecosystems. Through nutrient mineralization and mutualistic or antagonistic interactions with plants soil biota can affect plant performance and physiology and via this affect plant-associated aboveground insects. There is a large body of work in this field that has already been synthesized in various review papers. However, most of the studies have been carried out under highly controlled laboratory or greenhouse conditions. Here, we review studies that manipulate soil organisms of four dominant taxa (i.e. bacteria, fungi, nematodes and soil arthropods) in the field and assess the effects on the growth of plants and interactions with associated aboveground insects. We show that soil organisms play an important role in shaping plant-insect interactions in the field and that general patterns can be found for some taxa. Plant growth-promoting rhizobacteria generally have negative effects on herbivore performance or abundance, most likely through priming of defenses in the host plant. Addition of arbuscular mycorrhizal fungi (AMF) has positive effects on sap sucking herbivores, which is likely due to positive effects of AMF on nutrient levels in the phloem. The majority of AMF effects on chewers were neutral but when present, AMF effects were positive for specialist and negative for generalist chewing herbivores. AMF addition has negative effects on natural enemies in the field, suggesting that AMF may affect plant attractiveness for natural enemies, e.g. through volatile profiles. Alternatively, AMF may affect the quality of prey or host insects mediated by plant quality, which may in turn affect the performance and density of natural enemies. Nematodes negatively affect the performance of sap sucking herbivores (generally through phloem quality) but have no effect on chewing herbivores. For soil arthropods there are no clear patterns yet. We further show that the methodology used plays an impo
- Published
- 2018
27. Plant community composition but not plant traits determine the outcome of soil legacy effects on plants and insects
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Heinen, R., van der Sluijs, M., Biere, A., Harvey, J.A., Bezemer, T. Martijn, Heinen, R., van der Sluijs, M., Biere, A., Harvey, J.A., and Bezemer, T. Martijn
- Abstract
1.Plants leave species-specific legacies in the soil they grow in that can represent changes in abiotic or biotic soil properties. It has been shown that such legacies can affect future plants that grow in the same soil (plant-soil feedback, PSF). Such processes have been studied in detail, but mostly on individual plants. Here we study PSF effects at the community level and use a trait-based approach both in the conditioning phase and in the feedback phase to study how twelve individual soil legacies influence six plant communities that differ in root size. 2.We tested if (I) grassland perennial species with large root systems would leave a stronger legacy than those with small root systems, (II) grass species would leave a more positive soil legacy than forbs and (III) communities with large root systems would be more responsive than small-rooted communities. We also tested (IV) whether a leaf chewing herbivore and a phloem feeder were affected by soil legacy effects in a community framework. 3.Our study shows that the six different plant communities that we used respond differently to soil legacies of twelve different plant species and their functional groups. Species with large root systems did not leave stronger legacies than species with small root systems, nor were communities with large root systems more responsive than communities with root systems. 4.Moreover, we show that when communities are affected by soil legacies, these effects carry over to the chewing herbivore Mamestra brassicae (Lepidoptera: Noctuidae) through induced behavioral changes resulting in better performance of a chewing herbivore on forb-conditioned soils than on grass-conditioned soils, whereas performance of the phloem feeder Rhopalosiphum padi (Hemiptera: Aphididae) remained unaffected. 5.Synthesis: The results of this study shed light on the variability of soil effects found in previous work on feedbacks in communities. Our study suggests that th
- Published
- 2018
28. Data from: Responses of insect herbivores and their food plants to wind exposure and the importance of predation risk
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Chen, C., Biere, Arjen, Gols, R., Halfwerk, Wouter, Oers, C.H.J., Harvey, J.A., Chen, C., Biere, Arjen, Gols, R., Halfwerk, Wouter, Oers, C.H.J., and Harvey, J.A.
- Abstract
1. Wind is an important abiotic factor that influences an array of biological processes, but it is rarely considered in studies on plant-herbivore interactions. 2. Here, we tested whether wind exposure could directly or indirectly affect the performance of two insect herbivores, Plutella xylostella and Pieris brassicae, feeding on Brassica nigra plants. 3. In a greenhouse study using a factorial design, B. nigra plants were exposed to different wind regimes generated by fans before and after caterpillars were introduced on plants in an attempt to separate the effects of direct and indirect wind exposure on herbivores. 4. Wind exposure delayed flowering, decreased plant height and increased leaf concentrations of amino acids and glucosinolates. 5. Plant-mediated effects of wind on herbivores, i.e., effects of exposure of plants to wind prior to herbivore feeding, were generally small. However, development time of both herbivores was extended and adult body mass of P. xylostella was reduced when they were directly exposed to wind. By contrast, wind-exposed adult P. brassicae butterflies were significantly larger, revealing a trade-off between development time and adult size. 6. Based on these results, we conducted a behavioral experiment to study preference by an avian predator, the Great Tit (Parus major) for last instar P. brassicae caterpillars on plants that were exposed to either control (no wind) or wind (fan-exposed) treatments. Tits captured significantly more caterpillars on still than on wind-exposed plants. 7. Our results suggest that P. brassicae caterpillars are able to perceive the abiotic environment and to trade off the costs of extended development time against the benefits of increased size depending on the perceived risk of predation mediated by wind exposure. Such adaptive phenotypic plasticity in insects has not yet been described in response to wind exposure.
- Published
- 2018
29. Automated Volumetric Mammographic Breast Density Measurements May Underestimate Percent Breast Density for High-density Breasts
- Author
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Rahbar, K., Gubern Merida, A., Patrie, J.T., Harvey, J.A., Rahbar, K., Gubern Merida, A., Patrie, J.T., and Harvey, J.A.
- Abstract
Contains fulltext : 191364.pdf (Publisher’s version ) (Closed access), RATIONALE AND OBJECTIVES: The purpose of this study was to evaluate discrepancy in breast composition measurements obtained from mammograms using two commercially available software methods for systematic trends in overestimation or underestimation compared to magnetic resonance-derived measurements. MATERIALS AND METHODS: An institutional review board-approved, Health Insurance Portability and Accountability Act-compliant retrospective study was performed to calculate percent breast density (PBD) by quantifying fibroglandular volume and total breast volume derived from magnetic resonance imaging (MRI) segmentation and mammograms using two commercially available software programs (Volpara and Quantra). Consecutive screening MRI exams from a 6-month period with negative or benign findings were used. The most recent mammogram within 9 months was used to derive mean density values from "for processing" images at the per breast level. Bland-Altman statistical analyses were performed to determine the mean discrepancy and the limits of agreement. RESULTS: A total of 110 women with 220 breasts met the study criteria. Overall, PBD was not different between MRI (mean 10%, range 1%-41%) and Volpara (mean 10%, range 3%-29%); a small but significant difference was present in the discrepancy between MRI and Quantra (4.0%, 95% CI: 2.9 to 5.0, P < 0.001). Discrepancy was highest at higher breast densities, with Volpara slightly underestimating and Quantra slightly overestimating PBD compared to MRI. The mean discrepancy for both Volpara and Quantra for total breast volume was not significantly different from MRI (p = 0.89, 0.35, respectively). Volpara tended to underestimate, whereas Quantra tended to overestimate fibroglandular volume, with the highest discrepancy at higher breast volumes. CONCLUSIONS: Both Volpara and Quantra tend to underestimate PBD, which is most pronounced at higher densities. PBD can be accurately measured using automated volumetric software programs, but v
- Published
- 2017
30. Gold Open Access Publishing in Mega Journals: Developing Countries Pay the Price of Western Premium Academic Output
- Author
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Ellers, J., Crowther, T.W., Harvey, J.A., Ellers, J., Crowther, T.W., and Harvey, J.A.
- Abstract
Open access publishing (OAP) makes research output freely available, and several national governments have now made OAP mandatory for all publicly funded research. Gold OAP is a common form of OAP where the author pays an article processing charge (APC) to make the article freely available to readers. However, gold OAP is a cause for concern because it drives a redistribution of valuable research money to support open access papers in ‘mega-journals’ with more permissive acceptance criteria. We present a data-driven evaluation of the financial ramifications of gold OAP and provide evidence that gold OAP in mega-journals is biased toward Western industrialized countries. From 2011 to 2015, the period of our data collection, countries with developing economies had a disproportionately greater share of articles published in the lower-tier mega-journals and thus paid article APCs that cross-subsidize publications in the top-tier journals of the same publisher. Conversely, scientists from Western developed countries had a disproportionately greater share of articles published in those same top-tier journals. The global inequity of the cross-subsidizing APC model was demonstrated across five different mega-journals, showing that the issue is a common problem. We need to develop stringent and fair criteria that address the global financial implications of OAP, as publication fees should reflect the real cost of publishing and be transparent for authors.
- Published
- 2017
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31. Honey and honey-based sugars partially affect reproductive trade-offs in parasitoids exhibiting different life-history and reproductive strategies
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Harvey, J.A., Essens, Tijl, Las, Rutger, van Veen, Cindy, Visser, B., Ellers, Jacintha, Heinen, R., Gols, Rieta, Harvey, J.A., Essens, Tijl, Las, Rutger, van Veen, Cindy, Visser, B., Ellers, Jacintha, Heinen, R., and Gols, Rieta
- Abstract
Adult dietary regimes in insects may affect egg production, fecundity and ultimately fitness. This is especially relevant in parasitoid wasps where many species serve as important biological control agents of agricultural pests. Here, we tested the effect of honey and sugar diets on daily fecundity schedules, lifetime reproductive success and longevity in four species of parasitoid wasps when reared on their respective hosts. The parasitoid species were selected based on dichotomies in host usage strategies and reproductive traits. Gelis agilis and G. areator are idiobiont ecto-parasitoids that develop in non-growing hosts, feed on protein-rich host fluids to maximize reproduction as adults and produce small numbers of large eggs. Meteorus pulchricornis and Microplitis mediator are koinobiont endoparasitoids that develop inside the bodies of growing hosts, do not host-feed, and produce greater numbers of small eggs. Parasitoids were reared on diets of either pure honey (containing trace amounts of proteins), heated honey (with denatured proteins) and a honey-mimic containing sugars only. We hypothesized that the benefits of proteins in honey would enhance reproduction in the ectoparasitoids due to their high metabolic investment per egg, but not in the koinobionts. Pure honey diet resulted in higher lifetime fecundity in G. agilis compared with the honey-mimic, whereas in both koinobionts, reproductive success did not vary significantly with diet. Longevity was less affected by diet in all of the parasitoids, although there were variable trade-offs between host access and longevity in the four species. We argue that there are both trait-based and association-specific effects of supplementary nutrients in honey on reproductive investment and success in parasitoid wasps.
- Published
- 2017
32. Neutron Total Cross Sections of {sup 235}U From Transmission Measurements in the Energy Range 2 keV to 300 keV and Statistical Model Analysis of the Data
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Derrien, H., primary, Harvey, J.A., additional, Larson, N.M., additional, Leal, L.C., additional, and Wright, R.Q., additional
- Published
- 2000
- Full Text
- View/download PDF
33. Direct and indirect genetic effects in life-history traits of flour beetles (Tribolium castaneum)
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Ellen, E.D., Peeters, Katrijn, Verhoeven, Merel, Gols, Rieta, Harvey, J.A., Wade, M.J., Dicke, Marcel, Bijma, Piter, Animal Ecology, Amsterdam Global Change Institute, and Terrestrial Ecology (TE)
- Subjects
Pupal body mass ,Growth rate ,fungi ,Animal Breeding and Genomics ,Social interactions ,PE&RC ,Laboratorium voor Entomologie ,pupal body mass ,016-3911 ,international ,WIAS ,social interactions ,Fokkerij en Genomica ,Development time ,growth rate ,IGE ,EPS ,Laboratory of Entomology - Abstract
Indirect genetic effects (IGEs) are the basis of social interactions among conspecifics, and can affect genetic variation of nonsocial and social traits. We used flour beetles (Tribolium castaneum) of two phenotypically distinguishable populations to estimate genetic (co)variances and the effect of IGEs on three life-history traits: development time (DT), growth rate (GR), and pupal body mass (BM). We found that GR was strongly affected by social environment with IGEs accounting for 18% of the heritable variation. We also discovered a sex-specific social effect: male ratio in a group significantly affected both GR and BM; that is, beetles grew larger and faster in male-biased social environments. Such sex-specific IGEs have not previously been demonstrated in a nonsocial insect. Our results show that beetles that achieve a higher BM do so via a slower GR in response to social environment. Existing models of evolution in age-structured or stage-structured populations do not account for IGEs of social cohorts. It is likely that such IGEs have played a key role in the evolution of developmental plasticity shown by Tenebrionid larvae in response to density. Our results document an important source of genetic variation for GR, often overlooked in life-history theory.
- Published
- 2016
34. Intrinsic competition between primary hyperparasitoids of the solitary endoparasitoid Cotesia rubecula
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Zhu, Feng, Lammers, Mark, Harvey, J.A., Poelman, E.H., Terrestrial Ecology (TE), Animal Ecology, and Amsterdam Global Change Institute
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Contest competition ,Baryscapus galactopus contest competition insect parasitoid intrinsic competition Mesochorus gemeilus primary hyperparasitoid. induced plant volatiles parasitoid wasps interspecific competition gregarious development heliothis-virescens larval competition pieris-brassicae aphidius-ervi host hymenoptera Entomology ,Eco-evolutionary dynamics ,national ,017-3928 ,Intrinsic competition ,Baryscapus galactopus ,Laboratorium voor Entomologie ,Mesochorus gemellus ,Insect parasitoid ,Primary hyperparasitoid ,EPS ,Laboratory of Entomology - Abstract
1. In nature, competitive interactions occur when different species exploit similar niches. Parasitic wasps (parasitoids) often have narrow host ranges and need to cope with competitors that use the same host species for development of their offspring. When larvae of different parasitoid species develop in the same host, this leads to intrinsic and often contest com.petition. Thus far, m.ost studies on intrinsic competition have focused on primary parasitoids. However, competition among primary.hyperparasitoids, parasitic wasps that use primary parasitoids as a host, has been little studied. 2. This study investigated intrinsic competition between two primary hyperparasitoids, the gregarious Baryscapus galactopus and the solitary Mesochoru,s gemellu,s, which lay their eggs in primary parasitoid larvae of tesla rubecula, while those in turn are developing inside their herbivore host, Pieris rapae. The aims were to identify: (i) which hyperparasitoid is the superior competitor; and (ii) whether oviposition sequence affects the outcome of intrinsic competition. 3. The results show that B. galactopus won 70% of contests when the two hyperparasitoids parasitised the host at the same time, and 90% when 13. galactopus oviposited first. When M. gemellus had a 48 h head start, the two hyperparasitoids had an equal chance to win the competition. This suggests that M. galactopus is an intrinsically superior competitor to M. gemellu,s, Moreover, the outcome of competition is affected by time lags in oviposition events. 4. In contrast to what has been reported for primary parasitoids, we found that a. gregarious hyperparasitoid species had a competitive advantage over a solitary species.
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- 2016
35. Wasp-associated factors act in interspecies competition duing multparasitism
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Magdaraog, P.M., Tanaka, T., Harvey, J.A., Animal Ecology, and Amsterdam Global Change Institute
- Subjects
fungi - Abstract
Coexistence or displacement of parasitoids in hosts during intrinsic competitive interactions between different parasitoid species (multiparasitism) may depend on their life history traits and behavior. Intense competition for possession of hosts may lead to the elimination of the inferior competitor through physical attack and/or physiological suppression. However, the mechanisms of physiological suppression during multiparasitism remain unclear. Previous work has shown that first instar larvae of the solitary endoparasitoid Meteorus pulchricornis possess well-developed mandibles that are used to kill competitors. Two gregarious endoparasitoids, Cotesia kariyai and C. rufricus, share host resources especially when the time gap of oviposition is short. Here, we investigated the physiological influence of wasp-regulatory factors of the three endoparasitoids, M. pulchricornis, C. kariyai, and C. ruficrus, in their common host Mythimna separata. We found that MpVLP alone (or with venom) deleteriously affected the development of the two gregarious species. Similarly, CkPDV plus venom had toxic effect on M. pulchricornis eggs and immature larvae, although they were not harmful to immature stages of C. ruficrus. Cotesia kariyai and C. ruficrus were able to coexist mainly through the expression of regulatory factors and both could successfully emerge from a multiparasitized host. The injection of CkPDV plus venom after oviposition in L5 host larvae facilitated C. ruficrus development and increased the rate of successful parasitism from 9% to 62%. This suggests that the two gregarious parasitoid wasps exhibit strong phylogenetic affinity, favoring their coexistence and success in multiparasitized hosts.
- Published
- 2016
36. The importance of ecological fitting and novel resource consumer interactions in nature
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Malcicka, M., Harvey, J.A., Animal Ecology, and Amsterdam Global Change Institute
- Published
- 2016
37. Multi-trait mimicry of ants by a parasitoid wasp
- Author
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Malcicka, M., Bezemer, T.M., Visser, B., Bloemberg, M., Snart, C., Hardy, I.C.W., Harvey, J.A., HarveyJ.A., Netherlands Institute of Ecology, Institut de recherche sur la biologie de l'insecte UMR7261 (IRBI), Université de Tours (UT)-Centre National de la Recherche Scientifique (CNRS), University of Nottingham, UK (UON), School of Biosciences, Animal Ecology, Amsterdam Global Change Institute, HarveyJ.A., UCL - SST/ELI/ELIB - Biodiversity, and Terrestrial Ecology (TE)
- Subjects
Wasps ,Article ,Gas Chromatography-Mass Spectrometry ,Parasitoid wasp ,Black garden ant ,Animals ,Body Size ,Semiochemical ,Ecosystem ,Volatile Organic Compounds ,Multidisciplinary ,biology ,Ecology ,Ants ,Lasius ,Spiders ,Ant mimicry ,Ketones ,Cotesia glomerata ,biology.organism_classification ,[SDV.BA.ZI]Life Sciences [q-bio]/Animal biology/Invertebrate Zoology ,Ichneumonidae ,Drosophila melanogaster ,Predatory Behavior ,international ,Mimicry ,[SDV.EE.IEO]Life Sciences [q-bio]/Ecology, environment/Symbiosis - Abstract
International audience; Many animals avoid attack from predators through toxicity or the emission of repellent chemicals. Defensive mimicry has evolved in many species to deceive shared predators, for instance through colouration and other morphological adaptations, but mimicry hardly ever seems to involve multi-trait similarities. Here we report on a wingless parasitoid wasp that exhibits a full spectrum of traits mimicing ants and affording protection against ground-dwelling predators (wolf spiders). In body size, morphology and movement Gelis agilis (Ichneumonidae) is highly similar to the black garden ant (Lasius niger) that shares the same habitat. When threatened, G. agilis also emits a volatile chemical that is similar to an ant-produced chemical that repels spiders. In bioassays with L. niger, G. agilis, G. areator, Cotesia glomerata and Drosophila melanogaster, ants and G. agilis were virtually immune to spider attack, in contrast the other species were not. Volatile characterisation with gas chromatography-mass spectrometry identified G. agilis emissions as 6-methyl-5-hepten-2-one, a known insect defence semiochemical that acts as an alarm pheromone in ants. We argue that multi-trait mimicry, as observed in G. agilis, might be much more common among animals than currently realized.
- Published
- 2015
38. Effects of plant diversity and structural complexity on parasitoid behaviour in a field experiment
- Author
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Kostenko, O., Lammers, M., Grootemaat, S., Kroon, T., Harvey, J.A., Geem, M. van, Bezemer, T.M., Terrestrial Ecology (TE), Animal Ecology, and Amsterdam Global Change Institute
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Jacobaea vulgaris ,NIOO ,Dacnusa sibirica ,Natural enemies ,Structural complexity ,Biodiversity experiment ,Eulophidae ,Laboratory of Nematology ,Leaf-miner ,PE&RC ,Laboratorium voor Nematologie ,Plant species richness - Abstract
1. In natural ecosystems, plants containing hosts for parasitoids are often embedded within heterogeneous plant communities. These plant communities surrounding host-infested plants may influence the host-finding ability of parasitoids. 2. A release-recapture-approach was used to examine whether the diversity and structural complexity of the community surrounding a host-infested plant influences the aggregation behaviour of the leaf-miner parasitoid Dacnusa sibirica Telenga and naturally occurring local leaf-miner parasitoids. Released and locally present parasitoids were collected on potted Jacobaea vulgaris Gaertn.plants infested with the generalist leaf-miner Chromatomyia syngenesiae Hardy. The plants were placed in experimentally established plant communities differing in plant diversity (1-9 species) and habitat complexity (bare ground, mown vegetation, and tall vegetation). Additionally, parasitoids were reared out from host mines on the trap plants. 3. Plant diversity did not influence the mean number of recaptured D. sibirica or captures of other locally present parasitoids but the number of recaptured parasitoids was influenced by habitat complexity. No D. sibirica parasitoids were recaptured in the bare ground plots or plots with mown vegetation. The mean number of recaptured D. sibirica generally increased with increasing complexity of the plant community, whereas locally present parasitoids were captured more frequently in communities with more bare ground. There was a unimodal relationship between the number of reared out parasitoids and diversity of the surrounding vegetation with the highest density of emerged parasitoids at intermediate diversity levels. 4. The present study adds to the thus far limited body of literature examining the aggregation behaviour of parasitoids in the field and suggests that the preference of parasitoids to aggregate in complex versus simple vegetation is association specific and thus depends on the parasitoid species as well as the identity of the plant community.
- Published
- 2015
39. Integrating more biological and ecological realism into studies of multitrophic interactions
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Harvey, J.A., Malcicka, M., Ellers, J., Animal Ecology, Amsterdam Global Change Institute, and Terrestrial Ecology (TE)
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trait ,generation ,genotype ,voltine ,national ,Development ,parasitoid ,phenology - Published
- 2015
40. Climate change, range shifts and multitrophic interactions
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Harvey, J.A., Malcicka, M., Blanco, J.A., Blanco, J.A., Animal Ecology, and Amsterdam Global Change Institute
- Subjects
Extinction event ,biology ,Woolly mammoth ,Anthropocene ,Deforestation ,Woolly rhinoceros ,Ecology ,Biodiversity ,Environmental science ,Climate change ,Ecosystem ,biology.organism_classification - Abstract
Climate change represents one of the most serious threats to biodiversity and ecosystem functioning. The current rate of temperature change, driven primarily by the human combus‐ tion of fossil fuels, far exceeds rates that have occurred in at least 10,000 years (lower Pleisto‐ cene) and perhaps much longer (IPCC, 2014). That last major climate change event precipitated a mass extinction that led to the sudden demise of many large quadrupeds, including such characteristic species as the woolly mammoth, woolly rhinoceros, mastodon, giant elk, sabertoothed tiger and dire wolf [1]. One of the major differences between landscapes at the time of previous climate change events and the current one is that the biosphere is now dominated by a single species, Homo sapiens sapiens, which has profoundly altered and simplified many terrestrial and aquatic ecosystems. Thus, in addition to climate change, natural ecosystems have been altered by other human-induced changes including deforestation, eutrophication, over-harvesting, the introduction of non-native species and various types of pollution. Consequently, species and populations are being challenged by multiple stressors, making it more difficult for them to adapt to rapid shifts in climate regimes. One can strongly argue that we no longer live in the Holocene but in the Anthropocene [2,3].
- Published
- 2015
41. Recent neutron scattering results on high-temperature superconductors
- Author
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Mook, H.A., primary, Dai, P., additional, Aeppli, G., additional, Mason, T.E., additional, Hecker, N.E., additional, Harvey, J.A., additional, Armstrong, T., additional, Salama, K., additional, and Lee, D., additional
- Published
- 1994
- Full Text
- View/download PDF
42. Host size and spatiotemporal patterns mediate the coexistence of specialist parasitoids
- Author
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Universitat Politècnica de València. Instituto Agroforestal Mediterráneo - Institut Agroforestal Mediterrani, Ministerio de Educación, Pekas, Apostolos, Tena Barreda, Alejandro, Harvey, J.A., Garcia Marí, Ferran, Frago, Enric, Universitat Politècnica de València. Instituto Agroforestal Mediterráneo - Institut Agroforestal Mediterrani, Ministerio de Educación, Pekas, Apostolos, Tena Barreda, Alejandro, Harvey, J.A., Garcia Marí, Ferran, and Frago, Enric
- Abstract
[EN] Many insect parasitoids are highly specialized and thus develop on only one or a few related host species, yet some hosts are attacked by many different parasitoid species in nature. For this reason, they have been often used to examine the consequences of competitive interactions. Hosts represent limited resources for larval parasitoid development and thus one competitor usually excludes all others. Although parasitoid competition has been debated and studied over the past several decades, understanding the factors that allow for coexistence among species sharing the same host in the field remains elusive. Parasitoids may be able to coexist on the same host species if they partition host resources according to size, age, or stage, or if their dynamics vary at spatial and temporal scales. One area that has thus far received little experimental attention is if competition can alter host usage strategies in parasitoids that in the absence of competitors attack hosts of the same size in the field. Here, we test this hypothesis with two parasitoid species in the genus Aphytis, both of which are specialized on the citrus pest California red scale Aonidiella aurantii. These parasitoids prefer large scales as hosts and yet coexist in sympatry in eastern parts of Spain. Parasitoids and hosts were sampled in 12 replicated orange groves. When host exploitation by the stronger competitor, A. melinus, was high the poorer competitor, A. chrysomphali, changed its foraging strategy to prefer alternative plant substrates where it parasitized hosts of smaller size. Consequently, the inferior parasitoid species shifted both its habitat and host size as a result of competition. Our results suggest that density-dependent size-mediated asymmetric competition is the likely mechanism allowing for the coexistence of these two species, and that the use of suboptimal (small) hosts can be advantageous under conditions imposed by competition where survival in higher quality larger hosts m
- Published
- 2016
43. Black and Garlic Mustard Plants Are Highly Suitable for the Development of Two Native Pierid Butterflies
- Author
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Heinen, R., Harvey, J.A., Gols, Rieta, Heinen, R., Harvey, J.A., and Gols, Rieta
- Abstract
In multivoltine insects that oviposit and develop on short-lived plants, different herbivore generations across a growing season often exploit different plant species. Here, we compare the development time, pupal mass, and survival of two closely related oligophagous herbivore species on two species of brassicaceous plants that grow in different habitats and which exhibit little overlap in temporal growth phenology. In central Europe, the green-veined white butterfly, Pieris napi L., is bivoltine, whereas the small cabbage white butterfly, Pieris rapae L., has two to three generations a year. Moreover, P. napi is primarily found in moist, open (e.g., meadow), and forest habitats, whereas P. rapae prefers drier, open habitats. Both butterflies were reared on Garlic mustard (Alliaria petiolata), which is shade-tolerant and grows early in spring in forest undergrowth, and Black mustard (Brassica nigra), which prefers open disturbed habitats and is most common in summer. Both host plant species differ in other traits such as secondary chemistry. We hypothesized that, owing to habitat preference, P. napi would develop equally well on both plants but that P. rapae would perform better on B. nigra The results provide partial support for this hypothesis, as both herbivores performed equally well on A. petiolata and B. nigra However, there were differences in these parameters that were species-specific: on both plants P. rapae developed faster and had larger pupae than P. napi Our results show that specialized herbivores can exploit different species of related plants that grow at different times of the season, enabling them to have multiple generations.
- Published
- 2016
44. Plant quantity affects development and survival of a gregarious insect herbivore and its endoparasitoid wasp.
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Fei, M., Gols, R., Zhu, F., Harvey, J.A., Fei, M., Gols, R., Zhu, F., and Harvey, J.A.
- Abstract
Virtually all studies of plant-herbivore-natural enemy interactions focus on plant quality as the major constraint on development and survival. However, for many gregarious feeding insect herbivores that feed on small or ephemeral plants, the quantity of resources is much more limiting, yet this area has received virtually no attention. Here, in both lab and semi-field experiments using tents containing variably sized clusters of food plants, we studied the effects of periodic food deprivation in a tri-trophic system where quantitative constraints are profoundly important on insect performance. The large cabbage white Pieris brassicae, is a specialist herbivore of relatively small wild brassicaceous plants that grow in variable densities, with black mustard (Brassica nigra) being one of the most important. Larvae of P. brassicae are in turn attacked by a specialist endoparasitoid wasp, Cotesia glomerata. Increasing the length of food deprivation of newly molted final instar caterpillars significantly decreased herbivore and parasitoid survival and biomass, but shortened their development time. Moreover, the ability of caterpillars to recover when provided with food again was correlated with the length of the food deprivation period. In outdoor tents with natural vegetation, we created conditions similar to those faced by P. brassicae in nature by manipulating plant density. Low densities of B. nigra lead to potential starvation of P. brassicae broods and their parasitoids, replicating nutritional conditions of the lab experiments. The ability of both unparasitized and parasitized caterpillars to find corner plants was similar but decreased with central plant density. Survival of both the herbivore and parasitoid increased with plant density and was higher for unparasitized than for parasitized caterpillars. Our results, in comparison with previous studies, reveal that quantitative constraints are far more important that qualitative constraints on the performance of
- Published
- 2016
45. Integrating insect life history and food plant phenology: flexible maternal choice is adaptive.
- Author
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Fei, Minghui, Harvey, J.A., Weldegergis, B., Huang, T., Reijngoudt, K., Vet, L.E.M., Gol, R., Fei, Minghui, Harvey, J.A., Weldegergis, B., Huang, T., Reijngoudt, K., Vet, L.E.M., and Gol, R.
- Abstract
Experience of insect herbivores and their natural enemies in the natal habitat is considered to affect their likelihood of accepting a similar habitat or plant/host during dispersal. Growing phenology of food plants and the number of generations in the insects further determines lability of insect behavioural responses at eclosion. We studied the effect of rearing history on oviposition preference in a multivoltine herbivore (Pieris brassicae), and foraging behaviour in the endoparasitoid wasp (Cotesia glomerata) a specialist enemy of P. brassicae. Different generations of the insects are obligatorily associated with different plants in the Brassicaceae, e.g., Brassica rapa, Brassica nigra and Sinapis arvensis, exhibiting different seasonal phenologies in The Netherlands. Food plant preference of adults was examined when the insects had been reared on each of the three plant species for one generation. Rearing history only marginally affected oviposition preference of P. brassicae butterflies, but they never preferred the plant on which they had been reared. C. glomerata had a clear preference for host-infested B. rapa plants, irrespective of rearing history. Higher levels of the glucosinolate breakdown product 3-butenyl isothiocyanate in the headspace of B. rapa plants could explain enhanced attractiveness. Our results reveal the potential importance of flexible plant choice for female multivoltine insects in nature
- Published
- 2016
46. The importance of phenology in studies of plant-herbivore-parasitoid interactions
- Author
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Vet, Louise, Harvey, J.A., Gols, Rieta, Fei, Minghui, Vet, Louise, Harvey, J.A., Gols, Rieta, and Fei, Minghui
- Abstract
Thesis title: The importance of phenology in studies of plant-herbivore-parasitoid interactionsAuthor: Minghui FeiAbstractAs food resources of herbivorous insects, the quality and quantity of plants can directly affect the performance of herbivorous insects and indirectly affect the performance of natural enemies of the herbivorous insects. In nature, plant quality and quantity are dynamic and can change in individual plants over the course of a single growing season. Many multivoltine insects are known to attack short-lived annual plants that are present for only 2 or 3 months in the field. These short-lived plants may germinate and grow at different times and locations during the growing season. In this situation, each generation of insects is obligated to search for potentially new species of food plants across the growing season, which may differ in qualitative and quantitative traits. The aim of this thesis was to explore how seasonal phenology of potential food plants effects a multivoltine herbivore-parasitoid interaction. In particular, I examined potential qualitative and quantitative constraints imposed by the seasonal phenology of several food-plant species on the development and survival as well as on oviposition decisions of a gregarious specialist herbivorous insect and its natural enemy that both have multiple generations per year. As a model system, I used a multivoltine specialist herbivorous insect associated with different plant species, the large cabbage white butterfly, Pieris brassicae L., and its specialized multivoltine endoparasitoid, Cotesia glomerata L.. Pieris brassicae primary feed on plants in the large family Brassicaceae. I used three annual brassicaceous plants, Brassica rapa L., Sinapis arvensis L., and Brassica nigra L., which grow rapidly and exhibit differing phenologies, each growing within a short period of time and with little temporal overlap amongst them. These plants are known to serve as food plants for successive generati
- Published
- 2016
47. Genetic variation in plant chemistry : consequences for plant-insect interactions
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van der Putten, Wim, Harvey, J.A., Gols, Rieta, van Geem, Moniek, van der Putten, Wim, Harvey, J.A., Gols, Rieta, and van Geem, Moniek
- Abstract
Plants form the basis of many food webs and are consumed by a wide variety of organisms, including herbivorous insects. Over the course of evolution, plants have evolved mechanisms to defend themselves against herbivory, whereas herbivorous insects have evolved counter-mechanisms to overcome these defences (a.k.a. co-evolutionary arms races). Plant-insect interactions are not restricted to plants and their herbivores (bi-trophic interactions), but also involve natural enemies of the herbivores such as parasitoids and predators (tri-trophic interactions). Plant quality can affect the quality of the host or prey for parasitoids and predators, respectively. In addition, other plant traits are important in providing shelter, alternative food sources, or chemical cues that can be used for host/prey location. Moreover, as plants reside in both soil and air, they mediate interactions between organisms above- and belowground through changes in plant quality. Plant quality is determined by secondary metabolites and morphological traits that may negatively affect the performance of insects, as well as by primary metabolites that plants produce in order to grow, develop and reproduce, which also provide essential nutrients for insects. Natural plant populations often exhibit genetic variation in various plant traits that include, amongst others, primary and secondary chemistry. Genetic variation in plant defence traits, such as the production of secondary metabolites, can be under selection pressure from a suite of biotic and abiotic factors that vary in space and time. Herbivorous insects may encounter a wide range of plant metabolites because the total concentrations of primary and secondary metabolites and the concentrations of individual compounds vary between genetically different plants. Also as a consequence of genetic variation, plants can respond differently to herbivory in terms of induced defence chemistry and re-allocation of metabolites. The main aim of this thesi
- Published
- 2016
48. sup 56 Fe resonance parameters for neutron energies up to 850 keV
- Author
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Perey, C.M., primary, Perey, F.G., additional, Harvey, J.A., additional, Hill, N.W., additional, and Larson, N.M., additional
- Published
- 1990
- Full Text
- View/download PDF
49. Desiccation and cold storage of Galleria mellonella cadavers and effects on in vivo production of Steinernema carpocapsae
- Author
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Wang, Xin, Wang, Huan, Feng, Qing-zhou, Cui, Xi-yang, Liu, Ri-yue, Sun, Yan-bo, Li, Guo-chao, Tan, Hao, Song, Dong-min, Liu, Wen, Ruan, Wei-bin, Harvey, J.A., Animal Ecology, and Amsterdam Global Change Institute
- Subjects
fungi - Abstract
BACKGROUND: Direct application of insect cadavers infected with entomopathogenic nematodes (EPN) can successfully control target pest insects. Little is known about the effects of environmental factors (desiccation and temperature) on the production process for infective juveniles (IJ) in insects. RESULTS: We examined the effects of desiccation time and cold storage (6.7°C) on IJ production of the nematode Steinernemacarpocapsae in Galleriamellonella cadavers at 30.8 and 57% humidity. Under desiccation, the IJ yield in cadavers increased gradually and reached a maximum on day5. IJ yield gradually declined from day6 onwards and was almost zero by day15. In general, cold storage at 6.7°C caused negative effects on IJ production in desiccated cadavers. Approximately 56h post infection was the time at which nematodes were most sensitive to low temperatures during development in cadavers. Five-day desiccated cadavers generated higher mortality and more rapid death of Galleriamellonella larvae than using newly (day0) desiccated cadavers. CONCLUSION: This study describe methods of optimizing rearing techniques such as desiccation and cold storage to promote the mass production and application of EPN- infected host cadavers for the field control of insect pests. © 2013 Society of Chemical Industry.
- Published
- 2014
50. Habitat complexity reduces parasitoid foraging efficiency, but does not prevent orientation towards learned host plant odours
- Author
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Kruidhof, H.M., Roberts, A.L., Magdaraog, P.M., Muñoz, D., Gols, R., Vet, L.E.M., Hoffmeister, T.S., Harvey, J.A., Kruidhof, H.M., Roberts, A.L., Magdaraog, P.M., Muñoz, D., Gols, R., Vet, L.E.M., Hoffmeister, T.S., and Harvey, J.A.
- Abstract
It is well known that many parasitic wasps use herbivore-induced plant odours (HIPVs) to locate their inconspicuous host insects, and are often able to distinguish between slight differences in plant odour composition. However, few studies have examined parasitoid foraging behaviour under (semi-)field conditions. In nature, food plants of parasitoid hosts are often embedded in non-host-plant assemblages that confer both structural and chemical complexity. By releasing both naïve and experienced Cotesia glomerata females in outdoor tents, we studied how natural vegetation surrounding Pieris brassicae-infested Sinapis arvensis and Barbarea vulgaris plants influences their foraging efficiency as well as their ability to specifically orient towards the HIPVs of the host plant species on which they previously had a positive oviposition experience. Natural background vegetation reduced the host-encounter rate of naïve C. glomerata females by 47 %. While associative learning of host plant HIPVs 1 day prior to foraging caused a 28 % increase in the overall foraging efficiency of C. glomerata, it did not reduce the negative influence of natural background vegetation. At the same time, however, females foraging in natural vegetation attacked more host patches on host-plant species on which they previously had a positive oviposition experience. We conclude that, even though the presence of natural vegetation reduces the foraging efficiency of C. glomerata, it does not prevent experienced female wasps from specifically orienting towards the host-plant species from which they had learned the HIPVs.
- Published
- 2015
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