Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    The art of being small : brain-body size scaling in minute parasitic wasps
    Woude, Emma van der - \ 2017
    Wageningen University. Promotor(en): M. Dicke, co-promotor(en): H.M. Smid. - Wageningen : Wageningen University - ISBN 9789463436564 - 231
    brain - insects - neurons - scaling - cognitive development - vespidae - parasitoid wasps - cum laude - hersenen - insecten - neuronen - schaalverandering - cognitieve ontwikkeling - vespidae - sluipwespen

    Haller’s rule states that small animals have relatively larger brains than large animals. This brain-body size relationship may enable small animals to maintain similar levels of brain performance as large animals. However, it also causes small animals to spend an exceptionally large proportion of energy on the development and maintenance of energetically expensive brain tissue. The work that is presented in this thesis reveals how the smallest animals face the challenge to maintain ecologically required levels of cognitive performance, while being limited by small numbers of neurons and a restricted energy balance. Developing into a small adult has cognitive costs for the parasitic wasp Nasonia vitripennis, and relative brain size is strongly constrained in this species. The extremely small parasitic wasp Trichogramma evanescens forms an exception to Haller’s rule by showing isometric brain-body size scaling. Miniaturized insect species may apply this strategy to avoid the excessive energetic costs of relatively large brains, thereby achieving smaller brain and body sizes than would be possible in the situation that is described by Haller’s rule. This brain-scaling strategy does not result in affected memory performance of small T. evanescens compared to larger individuals, and appears to be facilitated by a large flexibility in the size of neural components, rather than in their number or structural complexity. Maintaining neural complexity may the underlying mechanism that maintains the cognitive abilities of the smallest brains, possibly at the cost of reduced longevity as a consequence of the small size of neuronal cell bodies. This strategy could form the art of being small.

    Sociale wespen zijn geweldige roofdieren
    Lucas Gomes Marques Barbosa, D. ; Dicke, M. - \ 2013
    Dierplagen informatie 16 (2013)3. - ISSN 1388-137X - p. 4 - 7.
    vespidae - vespula - ongedierte - sociale insecten - diergedrag - roofinsecten - zoekgedrag - vermin - social insects - animal behaviour - predatory insects - searching behaviour
    De meeste mensen zien sociale wespen als insecten die ons aan het eind van de zomer lastig vallen en kunnen steken. In die periode is de kolonie flink gegroeid en zoeken de wespen naar suikerbronnen, zie zij vinden in ons drinken, voedsel en ijsjes. Sociale wespen zijn echter niet alleen vervelende insecten, het zijn ook geweldige roofdieren.
    Zoekkaart Bewoners van het Bijenhotel, onderdeel van onderzoek bijen en bloemen in de stad
    Alebeek, F.A.N. van - \ 2013
    Lelystad :
    apidae - vespidae - mijten - parasieten - drosophilidae - beschrijvingen - activiteit - foto's - apidae - vespidae - mites - parasites - drosophilidae - descriptions - activity - photographs
    Zoekkaart met informatie en afbeelingen van bewoners van het bijenhotel en een zoekkaart met overige bezoekers van het bijenhotel zoals parasieten en andere beestjes. Deze zoekkaart is onderdeel van het project ' Bijen & Bloemen in de Stad 'van Landschapsbeheer Flevoland en Wageningen UR – PPO - AGV Lelystad.
    Overlast van wespen, maar welke soorten?
    Vliet, A.J.H. van - \ 2011
    Wageningen : Nature Today
    vespidae - insectenplagen - zoögeografie - vespidae - insect pests - zoogeography
    De verkoopcijfers van bestrijdingsmiddelen bieden interessante inzichten in de ontwikkeling van wespen door het jaar heen. Ze geven mede aan dat het wespenoverlastseizoen is begonnen. Van de verschillende wespensoorten zijn het vooral de Duitse wesp en gewone wesp die voor de overlast zorgen. De laatste jaren nemen de bergveldwesp en de Franse veldwesp toe. Ook de hoornaars nemen door heel Nederland toe nadat ze halverwege vorige eeuw vrijwel helemaal uit ons land verdwenen waren.
    Wesp doodt en demonteert zweefvlieg
    Vliet, A.J.H. van - \ 2009
    Nature Today 2009 (2009)09-08-2009.
    vespidae - hymenoptera - natuurlijke vijanden - diergedrag - vespidae - hymenoptera - natural enemies - animal behaviour
    In augustus zijn wespen op zoek naar zoetigheid en kunnen maar weinig mensen ze waarderen. Tot voor kort waren de wespen nog niet vervelend omdat ze de zoetigheid van de larven in het nest kregen. Als tegenprestatie moesten de werksters voedsel brengen. Het voedsel bestaat uit vliegen, muggen, rupsen en spinnen. In het bijgevoegde filmpje is te zien hoe een wesp een zweefvlieg in stukken bijt en de eetbare onderdelen een voor een naar het nest brengt
    Tailor-made memory: natural differences in associative olfactory learning in two closely related wasp species
    Berg, M. van den - \ 2009
    Wageningen University. Promotor(en): Marcel Dicke; Louise Vet, co-promotor(en): Hans Smid. - [S.l. : S.n. - ISBN 9789085853725 - 171
    cotesia glomerata - cotesia rubecula - vespidae - insectenplagen - pieris brassicae - pieris rapae - reuk - leren - geheugen - africhten van dieren - genexpressie - aminozuursequenties - modellen - sluipwespen - multitrofe interacties - cotesia glomerata - cotesia rubecula - vespidae - insect pests - pieris brassicae - pieris rapae - smell - learning - memory - training of animals - gene expression - amino acid sequences - models - parasitoid wasps - multitrophic interactions
    Learning and memory formation are often seen as traits that are purely beneficial, but they are associated with metabolic costs as well. Since costs and gains of learning and memory are expected to vary between species, the ease and speed with which stable (consolidated) long-term memory (LTM) is formed, is expected to differ between species. For animals that occupy different ecological niches, ‘slow’ learning may be as adaptive as ‘fast’ learning. If an animal encounters a relatively predictable environment during its lifetime, fast learning is a good strategy. If the environment is relatively unpredictable, however, an animal may need more time and experiences to evaluate information before storing it as long-lasting memories. This concept is known as tailor-made memories: a species learns in the way that is most favourable, given the circumstances. In order to assess how such tailor-made memories evolve, I have used a multitrophic model system. This system consisted of (1) two closely related parasitic wasps (Cotesia glomerata and C. rubecula) that show a profound difference in learning, (2) the herbivorous cabbage white butterfly larvae Pieris brassicae and P. rapae, in which the parasitic wasps lay their eggs, and (3) the host plants Brussels sprouts (Brassica oleracea var. Gemmifera) and nasturtium (Tropaeolum majus).

    In my experiments, the wasps could learn to associate the odours of a plant with the presence of suitable hosts, by having one or more oviposition experiences (‘conditioning trials’) on that plant. Previous experiments showed that C. glomerata needs only one conditioning trial to form LTM, whereas C. rubecula needs three trials spaced in time to do so. In addition to LTM, another form of consolidated memory exists; anaesthesia-resistant memory (ARM). Both LTM and ARM are resistant to retrograde amnesia, which can be induced by cooling the wasps after conditioning. In contrast to LTM however, ARM is not protein synthesis-dependent. It can therefore be seen as a ‘cheap’ form of long lasting memory. Consolidated memory in C. glomerata is thought to consist exclusively of LTM, whereas in C. rubecula it appears to be a mixture of both ARM and LTM.

    LTM formation requires protein synthesis, a process in which the transcription factor cAMP response element-binding protein (CREB) plays a key role. As a result of alternative splicing of the CREB mRNA transcript, the CREB protein occurs in different forms called isoforms. In model organisms such as the fruit fly Drosophila melanogaster, the mollusc Aplysia californica, and also in mammals such as mice and men, CREB isoforms have been shown to activate or repress transcription. Therefore, it has been hypothesized that the ratio of activator and repressor isoforms acts as a molecular switch for LTM formation. Such a switch could be responsible for species-specific differences in learning and memory.

    In this study the CREB gene of C. glomerata and C. rubecula was cloned and sequenced, and nine isoforms were identified in the two Cotesia species. The abundance of two of the nine mRNA variants coding for these isoforms differs significantly between C. glomerata and C. rubecula; the other variants are expressed similarly in both species. A conditioning trial, however, seems to induce changes in the expression of some of the major isoforms, indicating that the learning process itself may establish a ratio between activators and repressors that determines whether LTM is consolidated or not.

    Although such molecular mechanisms can potentially act very quickly, it may sometimes take up to days or weeks before information is stored in long-lasting memories. To explain how and why such differences in memory dynamics occur, we need insight in what happens when selection acts on natural variation in learning rate. In order to investigate this, I applied a bidirectional selection regime and reared two lines of C. glomerata wasps that differed significantly in learning rate (the decreased-learning line (DLL) and the increased-learning line (ILL)).

    By applying the protein synthesis inhibitor anisomycin before conditioning and measuring memory retention after conditioning, I showed that the memory consolidation dynamics of the selection lines differed. The DLL did not consolidate LTM anymore, whereas the ILL still did. By combining this study with experiments in which I induced retrograde amnesia by cooling at certain time intervals after conditioning, I demonstrated that in C. glomerata, anaesthesia-sensitive short-term memory directly consolidates into LTM, without an intermediate ARM phase. ARM represents a low-cost form of long-lasting memory (since it is not protein synthesis-dependent) and its presence is assumed to be favourable in animals that need more time to evaluate information, before storing it in the form of consolidated memories (e.g., in C. rubecula). The inability of C. glomerata to form ARM is costly because it may lead to an expenditure of energy (i.e., protein synthesis) on the ‘premature’ storage of unreliable information.

    Comparison of my selection lines showed that a high learning rate has costs. Longevity appeared to be significantly higher in wasps from the DLL than in those from the ILL. Moreover, females of the ILL have significantly larger brains than females from the DLL, while retaining a similar body size. These exciting results show that trade-offs occur (i.e., brain size vs. longevity) as a result of the bidirectional selection pressure that we applied. Moreover, the costs associated with a high learning rate seem to be of a constitutive nature. This means that animals that are able to quickly form consolidated memory pay for it by maintaining a large, costly brain and having a decreased lifespan, even when they do not actually use their learning abilities.

    The results of my work show that comparative research involving a model system consisting of two closely related animals with a natural difference in learning rate yields unique information, and is preferred over the use of ‘traditional’ model organisms. It enables testing of various hypotheses with an ecologically relevant learning paradigm. Neuroscience (and biology in general) would benefit greatly from an increase in the use of model systems that consist of closely related species that show differences in the trait of interest. The work described in this thesis shows how fruitful such a comparative approach can be.
    De betekenis van agrarisch natuurbeheer voor bijen en wespen op een melkveebedrijf in de Graafschap
    Guldemond, J.A. ; Pijfers, J.H.N. ; Belder, E. den - \ 2007
    Entomologische Berichten 67 (2007). - ISSN 0013-8827 - p. 198 - 203.
    apidae - soortenrijkdom - vespidae - natuurbescherming - broedplaatsen - habitats - agrarisch natuurbeheer - landschapselementen - achterhoek - apidae - species richness - vespidae - nature conservation - breeding places - habitats - agri-environment schemes - landscape elements - achterhoek
    Er is weinig bekend over het voorkomen van bijen en wespen op agrarische bedrijven. Daarom is op het Praktijkcentrum voor Melkveehouderij en Milieu ‘De Marke’ bij Hengelo, Gelderland, onderzoek gedaan naar de bijen- en wespensoorten die er voorkomen in samenhang met het gevoerde agrarisch natuurbeheer. Opvallend veel soorten zijn waargenomen: 81 bijensoorten, waarvan 14% op de Rode Lijst staat en 87 wespensoorten, waarvan 37% afneemt in Nederland. Dit illustreert wat een dergelijk beheer aan natuurwaarden kan opleveren. We doen aanbevelingen over de aanleg van natuurlijke elementen
    Nieuwe vindplaatsen van de zwamplatkopwesp Cephalonomia formiciformis (Hymenoptera: Bethylidae)
    Moraal, L.G. ; Rond, J. de - \ 2007
    Entomologische Berichten 67 (2007)4. - ISSN 0013-8827 - p. 150 - 151.
    vespidae - dode bomen - schimmels - bosecologie - waardplanten - vespidae - dead trees - fungi - forest ecology - host plants
    Onderzoek leverde 68 vindplaatsen op van insecten, die zich op zwammen van dikke dode bomen bevonden. Hun aanwezigheid zou er op kunnen wijzen, dat het doodhoutbeleid in Nederland zijn vruchten afwerpt. Dit was de reden voor onderhavig onderzoek, waarbij specifiek werd gezocht naar insecten, levend in de echte tonderzwam
    Courtship pheromones in parasitic wasps: comparison of bioactive and inactive hydrocarbon profiles by multivariate statistical methods
    Steiner, S. ; Mumm, R. ; Ruther, J. - \ 2007
    Journal of Chemical Ecology 33 (2007)4. - ISSN 0098-0331 - p. 825 - 838.
    female sex-pheromone - cuticular hydrocarbons - lariophagus-distinguendus - hymenoptera - pteromalidae - lipids - bethylidae - coleoptera - vespidae - behavior
    Cuticular hydrocarbons play a significant role in the regulation of cuticular permeability and also in the chemical communication of insects. In the parasitoid Lariophagus distinguendus (Hymenoptera: Pteromalidae), male courtship behavior is mediated by a female-produced sex pheromone. Previous studies have shown that the chemicals involved are already present in the pupal stage of both males and females. However, pheromonal activity in males decreases shortly after emergence. This pheromonal deactivation occurs only in living males, suggesting an active process rather than simple evaporation of bioactive compounds. Here, we present evidence that the sex pheromone of L. distinguendus is composed of a series of cuticular hydrocarbons. Filter paper disks treated with nonpolar fractions of cuticular extracts of freshly emerged males and females, 72-hr-old females, and yellowish pupae caused arrestment and stimulated key elements of courtship behavior in males, whereas fractions of 72-hr-old males did not. Sixty-four hydrocarbons with chain length between C25 and C37 were identified in the fractions by gas chromatography-mass spectrometry (GC-MS). Methyl-branched alkanes with one to four methyl groups were major components, along with traces of n-alkanes and monoalkenes. Principal component analysis, based on the relative amounts of the compounds, revealed that cuticular hydrocarbon composition differed among all five groups. By using partial least squares-discriminant analysis, we determined a series of components that differentiate bioactive and bioinactive hydrocarbon profiles, and may be responsible for pheromonal activity of hydrocarbon fractions in L. distinguendus.
    Gulzige vreters en irriterende brandharen
    Moraal, L.G. - \ 2006
    Tuin en Landschap 28 (2006)161. - ISSN 0165-3350 - p. 36 - 39.
    bomen - insectenplagen - bosplagen - bosschade - verspreiding - vespidae - coleoptera - thaumetopoea processionea - rupsen - trees - insect pests - forest pests - forest damage - dispersal - vespidae - coleoptera - thaumetopoea processionea - caterpillars
    Hoewel de eikenprocessierupsen vaak als eerste het nieuws halen, veroorzaakt een voorjaarstrio van groene eikenbladroller en de kleine en de grote wintervlinder de meeste schade bij Nederlandse bomen. Een overzicht van opvallende vreters en irriterende brandharen
    Associative learning in two closely related parasitoid wasps: a neuroecological approach
    Bleeker, M.A.K. - \ 2005
    Wageningen University. Promotor(en): Louise Vet, co-promotor(en): Hans Smid; Joop van Loon. - [S.l.] : S.n. - ISBN 9789085043201 - 135
    nuttige insecten - cotesia glomerata - cotesia rubecula - leervermogen - geurstoffen - reuk - neurofysiologie - vespidae - neurobiologie - beneficial insects - cotesia glomerata - cotesia rubecula - learning ability - odours - smell - neurophysiology - vespidae - neurobiology
    Insects are useful model organisms to study learning and memory. Their brains are less complex than vertebrate brains, but the basic mechanisms of learning and memory are similar in both taxa. In this thesis I study learning and subsequent memory formation in two parasitoid wasp species that differ in associative learning of the odours of plants on which they have encountered a host caterpillar. After ovipositing in a caterpillar on a certain plant species C. glomerata shifts its preference to the experienced plant odour, whereas C. rubecula does not shift plant odour preference after a similar experience. This difference in learning between these two closely related wasp species provides an attractive model to study physiological and ecological factors that could influence learning.

    As a first step to analyse possible physiological differences that could influence learning, I describe morphological, anatomical and histochemical aspects of the neural pathways that mediate associative learning of odours in these wasps. The two wasp species display a high degree of similarity in morphology of the olfactory pathway at both the level of the sensilla, and the level of the glomeruli, the primary olfactory neuropile. I furthermore identify the octopaminergic neurons that could mediate the reward stimulus in the two wasp species, but the results did not allow us to distinguish possible dissimilarities between the species.

    In addition I redefined the difference in preference learning between the two species in terms of associative and non-associative learning and analysed the temporal dynamics of the memory trace. Both wasps display associative learning after an oviposition reward conditioning, but the temporal dynamics differ. C. glomerata displays a stable memory for the experienced odour that lasts for at least five days, whereas in C. rubecula the memory starts to wane after one day.

    Finally, I studied the effect of physiological and ecological traits of hosts as possible factors influencing memory formation. For this I used two geographically disjunct populations of C. glomerata that differ in their host use. Both populations only change preference after an oviposition reward on their preferred host species, suggesting that physiological factors exert a major influence on learning in these two populations. I discuss the ultimate factors that could have contributed to a difference in learning in C. glomerata and C. rubecula
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