Colonization of eucalyptus in Brazil by an insect herbivore and its enemies: Herbivores find enemy-free space on a novel host plant
Grosman, A.H. - \ 2011
University of Amsterdam (UvA). Promotor(en): M.W. Sabelis; S.B.J. Menken. - - 143 p.
Towards spatial assessment of carbon sequestration in peatlands: spectroscopy based estimation of fractional cover of three plant functional types
Schaepman-Strub, G. ; Limpens, J. ; Menken, M. ; Bartholomeus, H. ; Schaepman, M.E. - \ 2009
Biogeosciences 6 (2009)2. - ISSN 1726-4170 - p. 275 - 284.
spectral reflectance measurements - growth forms - vegetation - sphagnum - leaf - boreal - bog - accumulation - stress
Peatlands accumulated large carbon (C) stocks as peat in historical times. Currently however, many peatlands are on the verge of becoming sources with their C sequestration function becoming sensitive to environmental changes such as increases in temperature, decreasing water table and enhanced nitrogen deposition. Long term changes in vegetation composition are both, a consequence and indicator of future changes in C sequestration. Spatial continuous accurate assessment of the vegetation composition is a current challenge in keeping a close watch on peatland vegetation changes. In this study we quantified the fractional cover of three major plant functional types (PFTs; Sphagnum mosses, graminoids, and ericoid shrubs) in peatlands, using field spectroscopy reflectance measurements (400-2400 nm) on 25 plots differing in PFT cover. The data was validated using point intercept methodology on the same plots. Our results showed that the detection of open Sphagnum versus Sphagnum covered by vascular plants (shrubs and graminoids) is feasible with an R-2 of 0.81. On the other hand, the partitioning of the vascular plant fraction into shrubs and graminoids revealed lower correlations of R-2 of 0.54 and 0.57, respectively. This study was based on a dataset where the reflectance of all main PFTs and their pure components within the peatland was measured at local spatial scales. Spectrally measured species or plant community abundances can further be used to bridge scaling gaps up to canopy scale, ultimately allowing upscaling of the C balance of peatlands to the ecosystem level.
Origins of asexuality in Bryobia mites (Acari: Tetranychidae)
Ros, V.I.D. ; Breeuwer, J.A.J. ; Menken, S.B.J. - \ 2008
BMC Evolutionary Biology 8 (2008). - ISSN 1471-2148 - 16 p.
wolbachia-induced parthenogenesis - oxidase subunit-i - leptopilina-clavipes hymenoptera - drosophila-simulans - mitochondrial-dna - phylogenetic-relationships - muscidifurax-uniraptor - bdelloid rotifers - spider-mite - sex
Background Obligate asexual reproduction is rare in the animal kingdom. Generally, asexuals are considered evolutionary dead ends that are unable to radiate. The phytophagous mite genus Bryobia contains a large number of asexual species. In this study, we investigate the origin and evolution of asexuality using samples from 111 populations in Europe, South Africa and the United States, belonging to eleven Bryobia species. We also examine intraspecific clonal diversity for one species, B. kissophila, by genotyping individuals from 61 different populations. Knowledge on the origin of asexuality and on clonal diversity can contribute to our understanding of the paradox of sex. Results The majority (94%) of 111 sampled populations reproduces asexually. Analysis of part of nuclear 28S rDNA shows that these asexuals do not form a monophyletic clade. Analysis of the mitochondrial COI region shows that intraspecific variation is extensive (up to 8.8%). Within B. kissophila, distinct clades are found, which are absent at the nuclear 28S rDNA level. Moreover, paraphyletic patterns are found at the mitochondrial DNA. Conclusion Asexuality is widespread in the genus Bryobia, signifying that some animal taxa do contain a high number of asexuals. We argue that asexuality originated multiple times within Bryobia. Wolbachia bacteria cause asexuality in at least two Bryobia species and may have infected different species independently. The high intraspecific clonal diversity and the patterns of paraphyly at the mitochondrial DNA in B. kissophila might be explained by a high mutation fixation rate and past hybridization events. Reproductive parasites like Wolbachia and Cardinium might influence these processes. We discuss the role these bacteria could play in the evolutionary success of asexual species.
|Water, gewoon bijzonder
Lyklema, J. - \ 2007
In: Water, bron van leven en ontwikkeling / Menken, S., Den Haag : Stichting Bio-wetenschappen en maatschappij (Cahiers bio-wetenschappen en maatschappij 26, no. 1) - ISBN 9789073196551 - p. 13 - 15.
|Towards the assessment of carbon sequestration in peatlands: estimation of the fractional cover of three plant functional types
Menken, M. ; Schaepman-Strub, G. ; Limpens, J. ; Schaepman, M.E. - \ 2007
- p. 1 - 1.
|Towards the Assessment of Carbon Sequestration in Peatlands - Estimating Plant Functional Type Fractional Cover
Menken, M. ; Schaepman-Strub, G. ; Limpens, J. ; Schaepman, M.E. - \ 2007
Butterfly, seedling, sapling and tree diversity and composition in a fire-affected Bornean rainforest
Cleary, D.F.R. ; Priadjati, A. ; Suryokusumo, B.K. ; Menken, S.B.J. - \ 2006
Austral Ecology: a journal of ecology in the Southern Hemisphere 31 (2006)1. - ISSN 1442-9985 - p. 46 - 57.
enso-induced fires - tropical forests - east kalimantan - el-nino - biodiversity - indicator - scale - consequences - communities - indonesia
Fire-affected forests are becoming an increasingly important component of tropical landscapes. The impact of wildfires on rainforest communities is, however, poorly understood. In this study the density, species richness and community composition of seedlings, saplings, trees and butterflies were assessed in unburned and burned forest following the 1997/98 El Nino Southern Oscillation burn event in East Kalimantan, Indonesia. More than half a year after the fires, sapling and tree densities in the burned forest were only 2.5% and 38.8%, respectively, of those in adjacent unburned forest. Rarefied species richness and Shannon's H' were higher in unburned forest than burned forest for all groups but only significantly so for seedlings. There were no significant differences in evenness between unburned and burned forest. Matrix regression and Akaike's information criterion (AIC) revealed that the best explanatory models of similarity included both burning and the distance between sample plots indicating that both deterministic processes (related to burning) and dispersal driven stochastic processes structure post-disturbance rainforest assemblages. Burning though explained substantially more variation in seedling assemblage structure whereas distance was a more important explanatory variable for trees and butterflies. The results indicate that butterfly assemblages in burned forest were primarily derived from adjacent unburned rainforest, exceptions being species of grass-feeders such as Orsotriaena medus that are normally found in open, disturbed areas, whereas burned forest seedling assemblages were dominated by typical pioneer genera, such as various Macaranga species that were absent or rare in unburned forest. Tree assemblages in the burned forest were represented by a subset of fire-resistant species, such as Eusideroxylon zwageri and remnant dominant species from the unburned forest.
Dipterocarpaceae: forest fires and forest recovery
Priadjati, A. - \ 2002
Wageningen University. Promotor(en): R.A.A. Oldeman; J. Soedarsono; S.B.J. Menken. - Wageningen : Tropenbos International - ISBN 9789058087539 - 214
dipterocarpaceae - bosbranden - verjonging - effecten - branden - shorea leprosula - milieufactoren - indonesië - dipterocarpaceae - forest fires - regeneration - effects - fires - shorea leprosula - environmental factors - indonesia
One of the serious problems Indonesia is facing today is deforestation. Forests have been playing a very important role in Indonesia as the main natural resources for the economic growth of the country. Large areas of tropical forests, worldwide considered to be among the richest in plant diversity, have been lost in recent years mainly due to inappropriate logging, illegal logging, shifting cultivation, and forest fires. The negative repercussions of these activities are felt from an economical as well as from an ecological point of view.
Time and again, Indonesia has experienced severe droughts often resulting in large forest fires. The fires used to occur only sporadically but now occur regularly every approx. 4 years in the area, with the largest and most destructive ones so far taking place in 1997-98. This climatic phenomenon was linked to a particularly pronounced El Niño Southern-Oscillation (ENSO), combined with numerous fires closely connected with human activities.
'Dipterocarpaceae: Forest fires and forest recovery' discusses a comprehensive ecological understanding of fires, an overview of forest dynamics after fires, and the restoration strategies of the forest. Planting materials are reviewed in terms of their genetic diversity and their growth in different soil substrates, with various mycorrhizal inoculations and levels of light. The present publication is the last in a series adding information to the earlier projects conducted by Smits (1994), Yasman (1995), Hatta (1999) and Omon (2002).
Microclimatic conditions change considerably after forest fires. The burned forest was characterized by elevated levels of light intensity and heat, and significantly reduced levels of humidity. After the fires, the natural dynamics of forest, in terms of regeneration of plants and butterfly communities, was set back to an earlier development phase where there were no more trees, only 2.5% of saplings survived and all saplings shorter than 5 m died. The butterfly community in the burned area had high densities of pioneer species associated with disturbed habitats. Burning caused a significant shift in the forest butterfly community. There was a highly significant variation in sapling and seedling density, diameter, and species richness between burned and unburned forest. Even though sapling height was significantly greater in burned than in unburned forest, there was no significant difference between their growth in both forests. The growth of both saplings and seedlings was completely unaffected by any edge effect in both forest types. The species richness, density and height of seedlings were significantly greater in unburned forest but their growth was significantly greater in burned forest. The diverse seedling community of unburned forest was replaced by a species-poor community of pioneers dominated by Euphorbiaceae.
Dipterocarp forests can recover from fire impact if the damage is not too extensive and the fires are not recurrent, but their natural recovery is too slow to make it economically interesting, and therefore foresters try to restore the desired state of high forest as soon as possible. Their measures are based on the fact that similar microclimatic conditions in both forest types were reached within two years, so assisted recovery can be implemented soon in the burned area by introducing valuable climax tree species i.e dipterocarp species, before they would arrive spontaneously.
Such operations require seedlings. Key issues for the management of dipterocarp stock plants in the nurseries included genetic diversity of the seedlings, choice and preparation of appropriate potting mixes, species-soil original matching, nursery hygiene and mycorrhizal inoculation. Cuttings grown in sandy loam showed a stronger and faster growth than the cuttings in sandy clay loam and loam. The higher sand fraction in the soil provided a good aeration for mycorrhizae and plants roots. Pasteurised soil media increased the growth of seedlings in the nursery. It is assumed that composition, acidity, moisture content and heat of the rooting media can be combined in a treatment optimising the conditions for both root development and root colonisation by fungi, thus increasing the quality and quantity of seedlings produced. It was found that interactions between so many factors lead to a highly complex situation, far from easy to control.
S. leprosulaproved to be very homogeneous as expressed from the similarities in frequencies of the band patterns. The similarity was relatively high between eastern, central and western Kalimantan populations but the nearer the geographic distance the more similar the populations.
The initial inoculation supported S. leprosula to start growing in the greenhouse. In the established dipterocarp nursery, the spores of mycorrhizal fungi inoculated seedlings easily and freely. In 15 months in the greenhouse, all seedlings were colonised by these mycorrhizal weed fungi. Laccaria sp. was the most common one, followed by Thelephora sp. , Riessiella sp. and Inocybe sp . After 12 months in the field, the species composition of mycorrhizal fungi involved in root colonisation changed again. Inocybe sp . was still there, with two new other species being most abundant, namely Amanita sp. and Scleroderma sp. Even though the growth of S. leprosula seedlings in the nursery was supported by initial inoculation, in the field, no initial inoculation seedlings showed a stronger growth because they benefited more from the late stage fungi infecting the plants at the planting location.
When dipterocarps are used, the key to success for a dipterocarp planting is species choice and light control. Selecting species suited to the local soil and site conditions is essential. Light control should correspond to the light requirements of a species during its growing stages, so planting methods should reflect site conditions and growth characteristics of the species. S. leprosula is a light-demanding species at the early stage, 60 to 73% (relative light intensity) for seedlings and 74 to 100% for saplings.
The assisted recovery of pure Imperata cylindrica areas after fires is accelerated using mixed plantations composed of indigenous fast-growing pioneer tree species, i.e Peronema canescens that offer suitable conditions for the establishment of indigenous dipterocarp species. In circumstances without stress by fire, a young P. canescens tree has a well-developed monopodial trunk with a light canopy so that the light intensity under this species is very high or not much lower than in the open site. This shade condition (semi-closed) is not very suitable for S. leprosula seedlings when under-planted under this species. The capacity of P. canescens after fires to reiterate abundantly ('traumatic reiteration') and converge architecturally from Scarrone's model to a physiognomy resembling Leeuwenberg's model provided more favourable environmental conditions for S. leprosula to grow under the canopy of these trees (closed stand). Within almost three years, S. leprosula saplings in a closed stand and in a semi-open area reached a height of 281 to 283 cm and a diameter of 33 to 34 mm, whereas in the open area and under the semi-closed canopy of. P. canescens they were only 165 to 193 cm high and 22 to 27 mm in diameter.
Long-term survival of a species depends on its ability to adapt to environmental change. Adaptability is a two-sided process. It rests on the optimal match between a genotype (organism) and its direct environment (ecosystem patch or 'eco-unit'). It is important to understand the reaction of the plants, so as to select genotypes adapted and adaptable to environmental stress in new environments. For this reason, next to the taxonomical data of S. leprosula , the architectural model and its reiteration are also described in this book.
In Chapter 7 an overview is provided of the fire and forest regeneration issues with special reference to the Dipterocarpaceae and Shorea leprosula . Much practical information is provided on conditions for a successful regeneration of Dipterocarpaceae. It is concluded that the Dipterocarpaceae have become a threatened plant family and that safeguarding the genetic diversity of Shorea leprosula is highly urgent. If Dipterocarpaceae are to survive, the issue of fires must be resolved and dealt with.
Effects of thrips feeding on tospovirus transmission in chrysanthemum
Wetering, F. van de - \ 1999
Agricultural University. Promotor(en): R.W. Goldbach; S.B.J. Menken; D. Peters; C. Mollema. - S.l. : S.n. - ISBN 9789058080103 - 120
chrysanthemum - thrips - voedering - plantenvirussen - plantenziekten - ziekteoverdracht - vectoren, ziekten - chrysanthemum - thrips - feeding - plant viruses - plant diseases - disease transmission - disease vectors
The introduction and rapid spread of Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) in Western Europe since the 1980s led to a considerable increase of losses in different, mainly ornamental crops due to tomato spotted wilt tospovirus (TSWV) infections. Besides the losses inflicted by TSWV, F. occidentalis itself is also an important pest on many of these crops. Chrysanthemum is one of those crops which is affected by both TSWV and its vector. Breeding and selection of this plant species has resulted in the identification of a few chrysanthemum cultivars with some partial resistance to thrips. However, resistant cultivars to TSWV have not been successfully developed yet, meaning that the control of TSWV has to rely on other strategies. Besides sanitation programs, other successful strategies to control TSWV or F. occidentalis are currently not available.
To develop durable and effective control measures and integrated pest management strategies, more detailed knowledge of the precise interactions between the virus, its vector and the threatened crop is required. Since transmission of TSWV is associated with ingestion of food, the feeding behaviour of thrips is one of the most determining factors in virus transmission. This study was therefore aimed to analyse the interactions between virus, vector and (chrysanthemum) plant in relation to thrips feeding.
Tospovirus is acquired by larvae and transmitted by old second instar larvae and adults after their emergence. As a first feature, the ability of larvae to acquire TSWV was analysed in relation to their age. The results obtained in a study with several F. occidentalis populations showed that the ability to acquire virus (defined as ingestion of virus by larvae, subsequently developing in viruliferous adults), dropped with the age of larvae. A notable result was obtained with one of the populations (NL3), which could only acquire TSWV when larvae were in their first larval (L1) stage.
Besides the age of the larvae at which they acquire virus, other parameters such as the F. occidentalis population involved, the feeding behaviour by the amount of food ingested, the virus species acquired and the host plant involved were studied for their effect on virus acquisition and transmission. Large and significant differences were found in TSWV transmission competencies between fourteen F. occidentalis populations which originated from different countries all over the world. These differences were not affected by the amount of virus ingested or the host used as virus source. However, the use of another tospovirus species, impatiens necrotic spot virus (INSV), influenced the transmission differences between populations. The transmission efficiencies found appeared to be rather constant, supporting the view that the competence of a population to transmit TSWV is a stable, and, therefore, inherited property.
The efficiency at which the F. occidentalis populations transmitted INSV was higher than that of TSWV. This observation confirms earlier reports that the different tospovirus species are transmitted at distinct rates by the same thrips population. It is likely that various isolates of TSWV will also be transmitted at different rates by one and the same F. occidentalis population as has been shown for some Thrips tabaci populations. In contrast to TSWV, INSV is acquired by L1s as well as second larval instars (L2s) of the NL3 population.
Further studies revealed that males of F. occidentalis are more efficient TSWV transmitters than females. This feature was found for all fourteen F. occidentalis populations tested. The differences in virus transmission competencies between both sexes can be explained by differences in their feeding behaviour. Males produce less silvery scars and make more frequent inoculation punctures than females. These punctures may represent the event during which the virus is successfully transmitted, as cells remain viable allowing virus to be replicated after virus-containing saliva injection. In addition, cells which are pierced and drained in the feeding process (resulting in silvery scars) are probably so destroyed that they will not support virus replication.
The different efficiencies by which males and females transmit virus may have an impact on the spread of the virus in a crop. Males may infect more plants than females as they show a higher mobility and the sex ratios in flights are male-biased. However, the contribution of males to the spread may be compensated or outweighed by the greater life expectation of females. Quantification of the development of an epidemic in terms of which part is caused by males and which by females, will be extremely difficult as the ratio between males and females will change continuously and their age can not accurately be determined.
To analyse whether thrips resistant chrysanthemum cultivars could effectively be used to control TSWV spread in this crop, fifteen cultivars were assessed for their susceptibility for this virus. All cultivars were susceptible, irrespective their degree of thrips resistance. However, the number of plants that attracted an infection varied for each cultivar. lt appeared in this study that the infection proceeds poorly in the infected plants and that the virus became unevenly distributed over the plant. A consequence of these observations is that in the chrysanthemum crop the virus will disperse slowly from primary infected plants. No L1s emerging on such plants, or only a small proportion of them, will acquire virus. With the development of the infection in the plant and development of the thrips population, more larvae will be able to acquire virus and thus become transmitters. This means that the early developing population of thrips found on primary infected plants by incoming (dispersing) adults will hardly contribute to the (intercrop) spread of the virus an that, with time, the infection pressure may increase from these primary infected plants. Studies on assessing the development of viruliferous thrips in a population on a primary infected chrysanthemum plant should enhance our understanding of TSWV spread in chrysanthemum.
In most cases, tospovirus infections have been attributed to virus introduction from sources located outside the crop, and less to secondary (intercrop) spread in the crop as reported for groundnut, tomato and pepper. The incidence of TSWV infections in the Dutch chrysanthemum crops is low, despite the fact that TSWV transmission to chrysanthemum occurs highly efficiently. Since the virus is not seed transmitted, the first infections may arise as a result from primary infections, subsequently followed by some secondary spread.
Using plants in testing the susceptibility of chrysanthemum for TSWV and vector resistance is a time- and labour-consuming activity. An expeditious leaf disk assay was introduced to assess this susceptibility. This assay was also used to quantify TSWV transmission to a partially vector-resistant and a susceptible cultivar. It was shown that the inoculation access period in which 50% of the disks became infected (IAP 50 ) was shorter for a partially vector-resistant cultivar than for a susceptible cultivar, indicating that TSWV is more efficiently transmitted to the more vector resistant cultivar. This may be the result of a different feeding behaviour on the less preferred, partially resistant cultivar, resulting in a higher frequency of inoculation punctures in a unit of time, and subsequently in greater probability of successful transmission.
The spread of TSWV will certainly be affected by the attractiveness of the plant as food source of the thrips. The lower development rate of viruliferous thrips and the shorter life expectancy on partially vector-resistant cultivars likely reduces secondary spread. On the contrary, the mobility and dispersal of thrips and subsequent TSWV transmission in enhanced on partially resistant vector plants, and hence, the use of vector-resistant cultivars may not under all circumstances lead to an effective control of TSWV spread.
Evolution of gustatory sensitivity in Yponomeuta caterpillars : sensitivity to the stereo-isomers dulcitol and sorbitol is localized in a single sensory cell
Roessingh, P. ; Hora, K.H. ; Loon, J.J.A. van; Menken, S.B.J. - \ 1999
Journal of Comparative Physiology A-Sensory Neural and Behavioral Physiology 184 (1999). - ISSN 0340-7594 - p. 119 - 126.
|Plants are better protected after exposure to infested conspecifics
Bruin, J. ; Groot, A.T. ; Sabelis, M.W. ; Dicke, M. - \ 1992
In: Proc.8th Int.Symp.Insect Plant Relationships / Menken, S.B.J., Visser, J.H., Harrewijn, P., Wageningen : - p. 357 - 358.
|Parasitoids foraging for leaf damage: do they see beyond the end of their antennae?
Wäckers, F. - \ 1992
In: Proc. 8th Int. Symp. Insect-plant relationships, S.B.J. Menken et al. (eds.). Wageningen. Kluwer Acad. Publ., Dordrecht - p. 359 - 360.
|Infochemicals that mediate plant-carnivore communication systemically induced by herbivory.
Dicke, M. - \ 1992
In: Proc. 8th Int. Symp. Insect-plant relationships, S.B.J. Menken et al. (eds.). Wageningen. Kluwer Acad. Publ. Dordrecht - p. 355 - 356.
|Mite herbivory causes better protection in downwind uninfested plants.
Bruin, J. ; Groot, A.T. ; Sabelis, M.W. ; Dicke, M. - \ 1992
In: Proc. 8th Int. Symp. Insect-plant relationships, S.B.J. Menken et al. (eds.). Wageningen. Kluwer Acad. Publ. Dordrecht - p. 357 - 358.
|Effects of spider mite infestation on biochemical characteristics of different gerbera cultivars.
Kielkiewicz, M. ; Dicke, M. - \ 1992
In: Proc. 8th Int. Symp. Insect-plant relationships, S.B.J. Menken et al. (eds.). Wageningen. Kluwer Acad. Publ. Dordrecht - p. 311 - 312.
|The behaviour of Nasonovia ribisnigri on resistant and susceptible lettuce lines.
Helden, M. van; Thijssen, M.H. ; Tjallingii, W.F. - \ 1992
In: Proc. 8th Int. Symp. Insect-plant relationships, S.B.J. Menken et al. (eds.). Wageningen. Kluwer Acad. Publ., Dordrecht - p. 286 - 288.
|Resistance of lettuce to the leaf aphid Macrosiphum euphorbiae.
Reinink, K. ; Dieleman, F.L. - \ 1992
In: Proc. 8th Int. Symp. Insect-plant relationships, S.B.J. Menken et al. (eds.). Wageningen. Kluwer Acad. Publ., Dordrecht - p. 291 - 292.
|Associative learning in host-finding by female Pieris brassicae butterflies: relearning preferences.
Loon, J.J.A. van; Everaarts, T.C. ; Smallegange, R.C. - \ 1992
In: Proc. 8th Int. Symp. Insect-plant relationships, S.B.J. Menken et al. (eds.). Wageningen. Kluwer Acad. Publ., Dordrecht - p. 162 - 164.
|Ultrastructure and electrical recording of sieve element punctures by aphid stylets.
Hogen Esch, Th. ; Tjallingii, W.F. - \ 1992
In: Proc. 8th Int. Symp. Insect-plant relationships, S.B.J. Menken et al. (eds.). Wageningen. Kluwer Acad. Publ., Dordrecht - p. 283 - 285.
|Criteria for host-plant acceptance by aphids.
Tjallingii, W.F. ; Mayoral, A. - \ 1992
In: Proc. 8th Int. Symp. Insect-plant relationships, S.B.J. Menken et al. (eds.). Wageningen. Kluwer Acad. Publ., Dordrecht - p. 280 - 282.