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  • 1
    Electronic Resource
    Electronic Resource
    Odour-mediated responses of phytophagous mites to conspecific and heterospecific competitors (1997)
    Springer
    Oecologia 110 (1997), S. 179-185 
    Details
    ISSN: 1432-1939
    Keywords: Key words Herbivore  ;  Avoidance  ;  Odour  ;   Competition  ;  Intra-guild predation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Plants under herbivore attack produce volatiles, thus attracting natural enemies of the herbivores. However, in doing so, the plant becomes more conspicuous to other herbivores. Herbivores may use the odours as a cue to refrain from visiting plants that are already infested, thereby avoiding competition for food, or, alternatively, to visit plants with defences weakened by earlier attacks. We investigated the response of one species of herbivore (the spider mite Tetranychus urticae) to odours emanating from cucumber plants infested by conspecific or heterospecific (the western flower thrips, Frankliniella occidentalis) herbivores. Olfactometer experiments in the laboratory showed that spider mites have a slight, but significant, preference for plants infested with conspecifics, but strongly avoid plants with thrips. These results were substantiated with greenhouse experiments. We released spider mites on the soil in the centre of a circle of six plants, half of which were infested with either conspecifics or heterospecifics (thrips), whereas the other half were uninfested. It was found that 60–70% of the mites were recaptured on the plants within 5 h after release. Results of these experiments were in agreement with results of the olfactometer experiments: (1) significantly fewer spider mites were found on plants infested with thrips than on uninfested plants and (2) more mites were found on plants with conspecifics than on clean plants (although this difference was not significant). From a functional point of view it makes sense that spider mites prefer clean plants over thrips-infested plants, since thrips are not only competitors, but are also known as intraguild predators of spider mites. Possible reasons for the slight attraction of spider mites to plants infested with conspecifics are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004420050147
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  • 2
    Electronic Resource
    Electronic Resource
    Habitat structure and population persistence in an experimental community (2001)
    [s.l.] : Macmillian Magazines Ltd.
    Nature 412 (2001), S. 538-543 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Understanding spatial population dynamics is fundamental for many questions in ecology and conservation. Many theoretical mechanisms have been proposed whereby spatial structure can promote population persistence, in particular for exploiter–victim systems (host–parasite/pathogen, ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/35087580
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  • 3
    Electronic Resource
    Electronic Resource
    Absence of odour-mediated avoidance of heterospecific competitors by the predatory mite Phytoseiulus persimilis (1999)
    Springer
    Entomologia experimentalis et applicata 92 (1999), S. 73-82 
    Details
    ISSN: 1570-7458
    Keywords: biological control ; food web interactions ; volatiles ; Phytoseiidae ; predatory bugs ; thrips ; predator-predator interactions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Arthropods use odours associated with the presence of their food, enemies and competitors when searching for patches. Responses to these odours therefore determine the spatial distribution of animals, and are decisive for the occurrence and strength of interactions among species. Therefore, a logical first step in studying food web interactions is the analysis of behaviour of individuals that are searching for patches of food. We followed this approach when studying interactions in an artificial food web occurring on greenhouse cucumber in the Netherlands. In an earlier paper we found that one of the predators of the food web, the predatory mite Phytoseiulus persimilis Athias-Henriot, used to control spider mites, discriminates between odours from plants with spider mites, Tetranychus urticae Koch, and plants with spider mites plus conspecific predators. The odours used for discrimination are produced by adult prey in response to the presence of predators, and probably serve as an alarm pheromone to warn related spider mites. Other predator species may also trigger production of this alarm pheromone, which P. persimilis could use in turn to avoid plants with heterospecific predators. We therefore studied the response of the latter to odours from plants with spider mites and 3 other predator species, i.e. the generalist predatory bug Orius laevigatus (Fieber), the polyphagous thrips Frankliniella occidentalis and the spider-mite predator Neoseiulus californicus (McGregor). Both olfactometer and greenhouse release experiments yielded no evidence that P. persimilis avoids plants with any of the 3 heterospecific predators. This suggests that these predators do not elicit production of alarm pheromones in spider mites, and we argue that this is caused by a lack of coevolutionary history. The consequences of the lack of avoidance of heterospecific predators for interactions in food webs and biological control are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003708512701
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  • 4
    Electronic Resource
    Electronic Resource
    Plants with spider-mite prey attract more predatory mites than clean plants under greenhouse conditions (1999)
    Springer
    Entomologia experimentalis et applicata 90 (1999), S. 191-198 
    Details
    ISSN: 1570-7458
    Keywords: olfactory searching ; synomones ; tritrophic interactions ; Phytoseiidae ; cucumber
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Although many predators and parasitoids are known to respond to odours produced by plants infested with their prey under laboratory conditions, there are actually few studies that show that this response leads to higher numbers of predators or parasitoids on the plants under natural conditions. Here we study the response of predatory mites (Phytoseiulus persimilis Athias-Henriot, Acari, Phytoseiidae) to odours from cucumber plants infested with two-spotted spider mites (Tetranychus urticae Koch, Acari, Tetranychidae) in greenhouse release experiments, where predators were released in the centre of a hexagon of cucumber plants. Forty to 57% of all predators released were recaptured on plants within 7 h. Of these, an average of 79.5% were found on infested plants, indicating that these attract about 4 times as many predators as do clean plants. Hence, the blind predatory mites were guided to the plants with prey by herbivore-induced odours produced by the plant, as was indicated by olfactometer experiments, where it was found that P. persimilis preferred odours from infested cucumber plants to odours from clean cucumber plants. The long-range searching behaviour of P. persimilis is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003551931509
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  • 5
    Electronic Resource
    Electronic Resource
    Attraction of a generalist predator towards herbivore-infested plants (1999)
    Springer
    Entomologia experimentalis et applicata 93 (1999), S. 303-312 
    Details
    ISSN: 1570-7458
    Keywords: Orius laevigatus ; Tetranychus urticae ; Frankliniella occidentalis ; searching behaviour ; preference ; conditioning
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The occurrence and strength of interactions among natural enemies and herbivores depend on their foraging decisions, and several of these decisions are based on odours. To investigate interactions among arthropods in a greenhouse cropping system, we studied the behavioural response of the predatory bug Orius laevigatus (Fieber) (Hemiptera: Anthocoridae) towards cucumber plants infested either with thrips (Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae)) or with spider mites (Tetranychus urticae Koch (Acari: Tetranychidae)). In greenhouse release-recapture experiments, the predatory bug showed a significant preference for both thrips-infested plants and spider mite-infested plants over clean plants. Predatory bugs preferred plants infested with spider mites to plants with thrips. Experience with spider mites on cucumber leaves prior to their release in the greenhouse had no effect on the preference of the predatory bugs. However, this experience did increase the percentage of predators recaptured. Y-tube olfactometer experiments showed that O. laevigatus was more attracted to odours from plants infested with spider mites than to odours from clean plants. Thus, O. laevigatus is able to perceive odours and may use them to find plants with prey in more natural conditions. The consequences of the searching behaviour for pest control are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003954022130
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  • 6
    Electronic Resource
    Electronic Resource
    Metapopulation dynamics of a persisting predator–prey system in the laboratory: time series analysis (1997)
    Springer
    Experimental and applied acarology 21 (1997), S. 415-430 
    Details
    ISSN: 1572-9702
    Keywords: metapopulations ; persistence ; acarine predator–prey dynamics ; Tetranychus urticae ; Phytoseiulus persimilis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The scarcity of experimental evidence for the persistence of predator–prey systems at the metapopulation level inspired us to developa simple predator–prey experiment that could be used for testingseveral theoretical predictions concerning persistence and its causes.The experimental system used consisted of one or several islands withsmall bean plants, the phytophagous mite Tetranychus urticaeand the predatory mite Phytoseiulus persimilis. In the firstexperiment, one large system was used consisting of 90 small bean plants,prey and predators. The system persisted for only 120 days. Second, asystem was used consisting of eight islands with ten plants each wherethe islands were connected by bridges. Two replicate experiments showedpersistence for at least 393 days. The difference between the first andthe second experiments suggests that the longer persistence is causedby a limited migration between the eight islands. Despite efforts to startboth replicates of the second experiment with similar initial conditions,the dynamics of both replicates varied substantially. In one replicatethe prey and predator numbers showed a trend through time, whereas thenumbers fluctuated around a fixed value in the other replicate. A timeseries analysis of the data of the prey and predators showed the presenceof periodicity with a lag of 8.5 weeks in one replicate, whereas such cyclicbehaviour was not found in the other replicate. The differences betweenthe two replicates suggest that it is difficult to perform experimentswhere one replicate is perturbed and the other serves as an undisturbedcontrol. We suggest using a longer time series, where a system is disturbedonly during the second half of the experiment. The data from the firstand second halves can subsequently be used to estimate the effect of theperturbation. The advantages and disadvantages of this method are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018479828913
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  • 7
    Electronic Resource
    Electronic Resource
    Improved control capacity of the mite predator Phytoseiulus persimilis (Acari: Phytoseiidae) on tomato (1997)
    Springer
    Experimental and applied acarology 21 (1997), S. 507-518 
    Details
    ISSN: 1572-9702
    Keywords: Phytoseiulus persimilis ; Tetranychus urticae ; biological control ; selection ; adaptation ; life-history traits ; food quality
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The predatory mite Phytoseiulus persimilis is frequently reported to perform poorly on greenhouse tomatoes. As the predators are mass-reared on another host plant (bean), we supposed that they are poorly adapted to tomato, a plant densely packed with poisonous and sticky glandular hairs. This hypothesis was tested by comparing the control capacity of a stain of P. persimilis directly obtained from a mass rearing with the same strain after four generations on tomato. Both strains were released in a tomato crop in two identical compartments of a greenhouse and the population dynamics of prey (a tomato strain of Tetranychus urticae) and predator were recorded at weekly time intervals. It was found that the strain previously exposed to a tomato environment performed better than the unexposed strain: (1) its population increased faster; (2) the prey population declined faster; and (3) the damage to new-grown tomato leaved was considerably lower. To investigate the caused of the difference in performance between the exposed and unexposed strains, oviposition and survival rates were assessed on a diet of two spotted spider mites on tomato leaf sections. In addition, the unexposed strian was tested on a diet of two-spotted spider mites on bean leaf sections. The difference in oviposition rates of both predator strains was small compare to the overall mean. however, the oviposition rate of the first generaton of predators since transfer from hean to tomato dropped to less than half of the original value. Moreover, mortality in the first generation increased from 14% to 89%, whereas it decreased to 0% after four generations. Future research should clarify whether these changes in life history are due to selection or tho physiological adaptation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/B:APPA.0000018885.35044.c6
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  • 8
    Electronic Resource
    Electronic Resource
    Review Behaviour and indirect interactions in food webs of plant-inhabiting arthropods (1998)
    Springer
    Experimental and applied acarology 22 (1998), S. 497-521 
    Details
    ISSN: 1572-9702
    Keywords: Food web ; intraguild predation ; apparent competition ; indirect interactions ; biological control ; semiochemicals ; searching behaviour ; odour-mediated avoidance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract With the increased use of biological control agents, artificial food webs are created in agricultural crops and the interactions between plants, herbivores and natural enemies change from simple tritrophic interactions to more complex food web interactions. Therefore, herbivore densities will not only be determined by direct predator–prey interactions and direct and indirect defence of plants against herbivores, but also by other direct and indirect interactions such as apparent competition, intraguild predation, resource competition, etc. Although these interactions have received considerable attention in theory and experiments, little is known about their impact on biological control. In this paper, we first present a review of indirect food web interactions in biological control systems. We propose to distinguish between numerical indirect interactions, which are interactions where one species affects densities of another species through an effect on the numbers of an intermediate species and functional indirect interactions, defined as changes in the way that two species interact through the presence of a third species. It is argued that functional indirect interactions are important in food webs and deserve more attention. Subsequently, we discuss experimental results on interactions in an artificial food web consisting of pests and natural enemies on greenhouse cucumber. The two pest species are the two-spotted spider mite Tetranychus urticae and the western flower thrips, Frankliniella occidentalis. Their natural enemies are the predatory mite Phytoseiulus persimilis, which is commonly used for spider mite control and the predatory mites Neoseiulus cucumeris and Iphiseius degenerans and the predatory bug Orius laevigatus, all natural enemies of thrips. First, we analyse the possible interactions between these seven species and we continue by discussing how functional indirect interactions, particularly the behaviour of arthropods, may change the significance and impact of direct interactions and numerical indirect interactions. It was found that a simple food web of only four species already gives rise to some quite complicated combinations of interactions. Spider mites and thrips interact indirectly through resource competition, but thrips larvae are intraguild predators of spider mites. Some of the natural enemies used for control of the two herbivore species are also intraguild predators. Moreover, spider mites produce a web that is subsequently used by thrips to hide from their predators. We discuss these and other results obtained so far and we conclude with a discussion of the potential impact of functional indirect and direct interactions on food webs and their significance for biological control.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006089924336
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  • 9
    Electronic Resource
    Electronic Resource
    Reproductive success ofAmblyseius idaeus andA. anonymus on a diet of two-spotted spider mites (1988)
    Springer
    Experimental and applied acarology 4 (1988), S. 41-51 
    Details
    ISSN: 1572-9702
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Amblyseius idaeus is a drought-resistant predatory mite of tetranychid spider mites. In this paper, life-history parameters ofA. idaeus and a morphologically similar species,A. anonymus, are measured and compared on a diet ofTetranychus urticae. Intrinsic rates of increase of both phytoseiids are similar, and are comparable to rates of phytoseiids that successfully controlTetranychus species. This makes both species promising candidates as biological control agents,A. idaeus especially under dry conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01213840
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  • 10
    Electronic Resource
    Electronic Resource
    Influence of humidity and water availability on the survival ofAmblyseius idaeus andA. anonymus (Acarina: Phytoseiidae) (1988)
    Springer
    Experimental and applied acarology 4 (1988), S. 27-40 
    Details
    ISSN: 1572-9702
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Amblyseius idaeus (Denmark & Muma) andA. anonymus Chant & Baker are morphologically very similar species of phytoseiids inhabiting areas in South America that have very different levels of humidity. Above 60% RH, nearly all eggs of both species hatch successfully, but below 60% RH the egg hatching rate ofA. anonymus is very poor, whereas eggs ofA. idaeus hatch at humidities as low as 30% RH. The mobile stages ofA. idaeus are better able to survive in absence of food and water than those ofA. anonymus. Water availability promotes survival of both species, but its effect onA. idaeus exceeds that onA. anonymus. These differences in low-humidity tolerance and survival ability are consistent with the climatic origin of these phytoseiid species;Amblyseius ideaus has been reported from very dry and humid areas, andA. anonymus from humid areas only. In comparison with other phytoseiid species, the eggs ofA. idaeus have the highest tolerance to low humidities reported to date, and, among the phytoseiids that are shown to be capable of controllingTetranychus spp., this tolerance appears to be exceptionally high. The impact of this result on the scope of biological control ofTetranychus spp. is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01213839
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