Tibor Kisbenedek

Hungarian Academy of Sciences, Budapest, Budapest fovaros, Hungary

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Publications (9)12.41 Total impact

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    ABSTRACT: Many hosts of the common cuckoo (Cuculus canorus) exhibit egg recognition, and reject parasitic eggs. How do hosts discriminate cuckoo eggs from their own? Hosts might be able to recognize their own eggs using the specific pigment pattern on the outer eggshell surface, which may serve as a cue for recognition. We tested if patterns of egg pigments (spottedness) contain this information by manipulating spot density of great reed warbler eggs (Acrocephalus arundinaceus). We also manipulated the colour of eggs when the original spot pattern remained the same. Spot density (approximately 15–75%) did not significantly affect rejection rate (8–20% rejection), but when spots fully covered the eggs, i.e. the eggshell was plain dark brown, rejection rate increased abruptly to 100%. A loglinear model revealed the significant influence of colour on rejection rates, although there was no interactive effect between spottedness and colour. Our results strongly support the differential use of egg markers in host’s egg discrimination, suggesting that spot density has limited importance compared to eggshell colour.
    Ethology 01/2008; 114(2):186-194. · 1.95 Impact Factor
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    ABSTRACT: The aims of this study were to test the influence of grazing intensity, effects of local and landscape parameters, and regional effects on orthopteran assemblages. We made our investigations on extensively and intensively grazed cattle pastures in three regions of the Hungarian Great Plain. The regions differed in landscape complexity; one region was situated in a structurally simple landscape with large landscape units, one in a structurally complex landscape with marshy patches and trees in the grasslands and one in a landscape with intermediate structural complexity. In each region we had seven pairs of differently managed grasslands, which differed in grazing intensity. Grasshoppers were recorded once in July 2003 using sweepnet catches and visual and acoustic observations in two 95 m long transects at each site (84 transects in total). Botanical surveys and measurements of other local factors were also made for each transect. After samplings, we digitised the most important land-use types using aerial photographs to produce landscape scale parameters within 100 and 500 m circles around every site. Analysing the management, regional, landscape and local effects on species richness with linear mixed models, we showed only strong significant regional differences. Linear mixed models for Orthoptera abundance yielded significant regional effects and marginal management effects. However, after including local and landscape parameters in a separate model a marginal local effect was found instead of a management effect in addition to the significant regional effect. Logistic regression models of 15 species also revealed the importance of local factors, particularly the importance of grass height, which is highly dependent on grazing intensity. We conclude that management intensity has indirect effects on Orthoptera species richness and abundance. Landscape scale parameters are also important, at least for some species.ZusammenfassungDas Ziel dieser Untersuchung war es, den Einfluss der Beweidungsintensität, die Effekte lokaler bzw. Landschaftsparameter sowie regionale Effekte auf die Vergesellschaftungen von Orthoptera zu testen. Wir führten unsere Untersuchung auf extensiv und intensiv beweideten Rinderweiden in drei Regionen der großen ungarischen Ebene durch. Die Regionen unterschieden sich in der Komplexität der Landschaft: eine Region lag in einer strukturell einfachen Landschaft mit großen Landschaftseinheiten, eine in einer strukturell komplexen Landschaft mit sumpfigen Flecken sowie Bäumen in den Grünländern und eine in einer Landschaft mit einer mittleren strukturellen Komplexität.In jeder Region befanden sich sieben Paare von unterschiedlich bewirtschafteten Grünländern, die sich in der Beweidungsintensität unterschieden. Die Grashüpfer wurden einmal im Juli 2003 erfasst, indem Streifnetzfänge sowie visuelle und akustische Beobachtungen auf zwei 95 m langen Transekten in jedem Gebiet durchgeführt wurden (insgesamt 84 Transekte). Es wurden darüber hinaus für jedes Transekt botanische Erfassungen und Messungen anderer lokaler Faktoren durchgeführt. Nach der Beprobung wurden die wichtigsten Landnutzungstypen mithilfe von Luftbildern digitalisiert um Parameter der Landschaftsskalen innerhalb eines Radius von 100 und 500 m um jedes Gebiet zu schaffen. Durch die Analyse der Effekte der Bewirtschaftung, regionaler und lokaler Effekte sowie von Landschaftseffekten auf den Artenreichtum mithilfe von linearen gemischten Modellen zeigten wir nur einen stark signifikanten regionalen Unterschied. Lineare gemischte Modelle für die Orthoptera-Abundanz zeigten signifikante regionale Effekte und geringfügige Bewirtschaftungseffekte. Wurden jedoch lokale und Landschaftsparameter in einem separaten Modell mit einbezogen, wurde ein geringfügiger lokaler Effekt anstelle eines Bewirtschaftungseffekts zusätzlich zum signifikanten regionalen Effekt gefunden. Logistische Regressionsmodelle von 15 Arten offenbarten auch die Wichtigkeit lokaler Faktoren, besonders der Grashöhe, die stark von der Beweidungsintensität abhängt. Wir schlossen daraus, dass die Bewirtschaftungsintensität indirekte Effekte auf den Artenreichtum und –abundanz der Orthoptera hat. Parameter der Landschaftsskala sind zumindest für einige Arten ebenfalls wichtig.
    Basic and Applied Ecology. 05/2007;
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    ABSTRACT: We tested the importance of nest cleaning in egg rejection behaviour of the great reed warbler Acrocephalus arundinaceus in a highly parasitised population in which about 64% of nests are parasitised by the common cuckoo Cuculus canorus. Three types of objects of the same weight, texture and colour but with different shapes (dummy cuckoo eggs, sticks and disks) were placed into great reed warbler nests. We investigated the response of hosts in two stages of breeding: pre-incubation when the risk of brood parasitism is high, and during incubation when the risk of parasitism is low. The dummy cuckoo eggs were rejected less often than the other objects in both breeding stages, although we did not find any difference in the frequency of rejection between pre-incubation and incubation. We integrate these results into current views on the evolution of host–parasite interactions, and propose a hierarchical concept to understand egg rejection behaviour: (1) hosts reject all non-egg shaped objects as a general cleaning mechanism; (2) adaptations for the hosts' ability to recognise their own eggs allows them to distinguish these eggs from similar objects and parasitic eggs.
    Journal of Avian Biology 02/2003; 34(1):16 - 19. · 2.02 Impact Factor
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    ABSTRACT: In the continuing arms race between hosts and brood parasites, hosts are expected to reduce variation in the appearance of their own eggs within clutches, as it facilitates recognition of parasitic eggs. At the same time, by increasing interclutch variation, hosts should make it more difficult for parasites to evolve perfectly mimetic eggs. In this study, we experimentally manipulated intraclutch variation in the great reed warbler, Acrocephalus arundinaceus, in Hungary, where this species is heavily (c. 64%) parasitized by the common cuckoo, Cuculus canorus. We placed artificial cuckoo eggs, which appeared moderately mimetic to humans, in two groups of nests; in one group we increased variability of egg appearance within clutches by exchanging host eggs among nests. These clutches showed a significantly higher intraclutch variability than natural clutches, which we used as a control group. Our results indicate that it has no effect on rejection behaviour in this species, neither when variation was increased experimentally, nor within the natural range of variation displayed by our population. We suggest that when parasitism is high, selection for reduced intraclutch variation may be less important than frequency-dependent selection for increased variation between individuals within a host population.
    Ethology 12/2002; 109(1):15 - 22. · 1.95 Impact Factor
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    ABSTRACT: Egg rejection behaviour towards parasitic eggs was studied in a great reed warbler Acrocephalus arundinaceus population in central Hungary, which was heavily (about 65%) parasitised by the common cuckoo Cuculus canorus. Clutches were experimentally parasitised during the egg-laying period with artificial, moderately mimetic cuckoo eggs or with conspecific eggs that were good mimics of the hosts' eggs. Great reed warblers rejected 76.2% of the artificial cuckoo eggs, mainly by ejection, but accepted most of the conspecific eggs (87.5%). Cuckoo eggs in naturally parasitised clutches were rejected at a lower rate (32%). When, in addition to the egg mimicry experiments, a stuffed cuckoo was placed near the nest, accompanied by the recording of a female cuckoo call, hosts' rejection rate of the artificial cuckoo egg increased from 76% to 96%. The sight of the cuckoo, on the other hand, did not influence host's rejection behaviour when a conspecific egg was used in the experiment. A stuffed collared dove Streptopelia decaocto, accompanied by its call, was used as a control, and did not cause any increased rejection. Great reed warblers were more aggressive towards the cuckoo than to the dove dummy. When the cuckoo eggs in naturally parasitised clutches were exchanged with artificial cuckoo eggs, we observed no increase in the rejection rate. We conclude that great reed warblers in our heavily parasitised population are capable of detecting brood parasitism in their clutch by identifying the parasitic egg. The efficiency of this identification depends mainly on the mimicry of the foreign egg. The sight of the cuckoo at the nest may increase rejection rate by stimulus summation, and this conditional effect is mainly affected by the degree of mimicry of the parasitic egg.
    Journal of Avian Biology 11/2002; 33(4):420 - 425. · 2.02 Impact Factor
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    András Báldi, Tibor Kisbenedek
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    ABSTRACT: 1 Bird species numbers were studied on 109 reed islands at Lake Velence, Hungary, in the 1993 and 1994 breeding seasons. The aim was to describe and account for the abundance and distribution patterns of the bird species.2 It was expected that an exponential model would fit the calculated species–area curves. However, for the 1993 data, both the power function (LogS ~ LogArea) and the exponential (S ~ LogArea) models did so, while the power function, exponential and linear (S ~ A) models fitted the curves for the 1994 data.3 The results showed that the pattern was not random: a collection of small islands held more species than a few large islands with the same total area.4 The relative species richness of small islands is a result of the preference of most common passerine bird species for the edges of reed islands. Most individuals were found in the first 5 m of the reedbed, and no edge avoidance was detected on a local spatial scale. Large, rarer species (e.g. Great White Egret), however, were found to be dependent on large reed islands.5 Comparison of results with two other studies on bird communities of reed islands revealed that the type of landscape matrix (e.g. deep water, shallow water or agricultural lands) among reed patches significantly influences bird communities. Deep water was dominated by grebes and coot, shallow water by reed-nesting passerines, and farmed areas by reed- and bush-nesting passerines.
    Global Ecology and Biogeography. 10/2000; 9(6):451 - 461.
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    András Báldi, Tibor Kisbenedek
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    ABSTRACT: Distribution of orthopterans were studied in 27 steppe patches in the Buda Hills, Hungary. The smallest patches were about 300 m2, the largest ‘continents’ were over 100 000 m2. We collected 692 imagoes of 32 species and 1 201 imagoes of 28 species in July 1992 and July 1993, respectively. We found that the best-fit models for the species-area curves were both the power function and exponential models. The multivariate regression model incorporated area and distance from large patches as significant factors in determining the number of species. The correlation analysis revealed that the elevation and the height of grass vegetation also influenced the distribution of species. We applied three methods for testing whether the distribution of orthopterans was random or not. First, we compared the observed species-area curves with the expected curves. Second, we compared the small-to-large and large-to-small cumulative curves. Finally, we compared the observed species-area curves with the rarefaction curves. All three methods for both years showed that the occurrence of orthopterans in the steppe patches was not random. A collection of small islands harboured more orthopteran species than one or two large patches of the same area.
    Acta Oecologica 01/1999; · 1.62 Impact Factor
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    Báldi A, Kisbenedek T
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    ABSTRACT: Grasslands are among the most threatened habitats on Earth, as large areas have been transformed into agricultural lands. Therefore, the registration of the state of grassland remnants is of crucial importance for conservation. An easy way to survey or monitor a habitat is to choose adequate indicator taxa. North American studies showed that grasshopper communities are good indicators of disturbance. We tested this observation for Hungarian steppes. The orthopteran assemblages of three steppe patches in the Buda Hills (Hungary) were sampled. One site was newly abandoned arable land, the second was a secondary meadow with large mammal grazing pressure, the third was a strictly protected seminatural steppe meadow. Our study in Hungarian steppe remnants supports earlier findings that orthopterans are good indicators for disturbance and naturalness. We found that density was highest on the most disturbed site, while species richness and diversity indices were greatest on the seminatural site. We argue that the use of simple statistical tests (X 2 and rank correlation analysis) may be favoured in inventories or monitoring programs instead of complicated multivariate analysis (e.g., detrended correspondence analysis). The rank correlation analysis on the species abundance/site matrices proved to be the most effective tool in finding differences and similarities between orthopteran communities. Published by Elsevier Science B.V.
    Agriculture Ecosystems & Environment 01/1997; 66:121-129. · 2.86 Impact Factor
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    ABSTRACT: A madarak költésparazitizmusa a gazdafaj és a költésparazita közötti koevolúció példái. A közismert kakukk (Cuculus canorus) Magyarországon szokatlanul nagymértékben (41-68%) parazitálja a nádirigót (Acrocephalus arundinaceus), lecsökkentve annak reprodukciós sikerét. A jelen OTKA pályázatban a két faj koevolúciós adaptációit kutattuk, így pl. a gazda tojásdiszkriminációs viselkedését (tojáseltemetés, tojáskidobás és fészekelhagyás). Kimutattuk, hogy a nádirigó fejlett tojásfelismeréssel rendelkezik, s a tojások alapszíne és nem a foltozottság játszik elsődleges szerepet az idegen tojások felsimerésében. Ugyancsak kimutattuk és egy modellel érzékeltettük, hogy a gazdák felismerik saját tojásaikat és memória-sablonnal rendelkeznek róla, s ennek szűk tartományában fogadnak el mimikris kakukktojásokat. A fészekaljon belüli tojások foltozottságnak viszont együttesen van szerepe, azok kis változatossága elősegíti az idegen tojás felismerését, míg azok nagy változatossága gyengíti. Többszörös parazitizmusban a nádirigók kisebb mértékben tudják elutasítani a kakukktojásokat, s így nagyobb lesz a költésparazita reprodukciós sikere. Többek között vizsgáltuk még a kakukkfióka kihordási ösztönének az okát, azaz a tojásból kikelő fióka minden tojást és fiókát kidob a fészekből 3 napon belül. Kísérleteink szerint ennek oka, hogy jobban ki tudja sajátítani a forrásokat ha egyedül van a fészekben, s a gazdákat nagyobb méretű táplálék gyűjtésére ösztönzi. | Cases of avian brood parasitism are examples for coevolution between hosts and brood parasites. In Hungary, the well-known common cuckoos (Cuculus canorus) parasitize great reed warblers (Acrocephalus arundinaceus) at an unusually high rate (41-68%), reducing their reproductive success. We studied coevolutionary adaptations between hosts and brood parasites within the framework of the present OTKA grant, e.g. egg discrimination ability of hosts (egg burial, egg ejection and nest desertion). We showed the well-developed egg discrimination ability of great reed warblers, and the importance of background colour of eggs in respect to spottedness in egg recognition. We also revealed and showed by a model that hosts know their own eggs and have a memory-template of these eggs. They accept mimetic cuckoo eggs if their characteristics fall below the acceptance threshold. We showed that intraclucth variation of eggshell spottedness facilitates foreign egg recognition if intraclucth variation is low, but it was found an opposite effect if it was high. In multiple parasitism hosts showed high tolerance toward cuckoo eggs, resulted in a higher fledging success of the brood parasite. We also revealed that the cuckoo chicks grow up alone in host nests to utilize parental provisioning ability of hosts better than in mixed broods of hosts and cuckoos.