Mobbing is a prey antipredator behaviour aimed to reduce the risk of predation. The behaviour may be innate and/or learned. Evaluating this behaviour on a large spatial scale can help to explore the ...mechanisms behind it. Using a playback experiment, I investigated variation in antipredator behaviour in small passerines in response to vocalisation from a potential predator, Eurasian pygmy owl (
Glaucidium passerinum
), at 105 sites in 35 localities within and outside the owl’s breeding range. While the birds outside the owl’s breeding range did not respond to the owl’s call, they mobbed at about 60% of the sites within the owl’s breeding range. At sites where the birds did not respond to the owl presentation, alarm calls of forest passerines were broadcasted to them. The birds always mobbed in response to the playback of these alarm calls. These results indicate that the birds’ response to the owl call may be a plastic trait induced by learning, while the response to the alarm calls of birds may be innate, as predation pressure in general can be strong enough to cause directional selection on the prey’s response to the alarm signalling of other birds.
Introduction
Knowledge on the mobility of threatened species is a clue to understanding population dynamics and is needed to develop appropriate conservation strategies. Here, we investigate movement ...patterns of the Bei-Bienko’s Plump Bush-cricket (
Isophya beybienkoi
), an example of a flightless and critically endangered species endemic to the Slovak Karst (southern Slovakia, Central Europe). The capture-mark-recapture method was used to estimate the mobility of the species using fluorescent dye as a marking medium. We found that the mean (± SD) daily distance travelled by this species was only 3.2 ± 2.6 m, with significant differences between males (4.1 ± 3.0 m) and females (2.7 ± 2.1 m). Our results indicate that
I. beybienkoi
is a short-distance disperser. Males disappeared faster than females from the study plots (at maximum, two females were recaptured even after 41 days). The observed movement patterns suggest that the most urgent conservation measure for this species is to improve the habitat quality of sites, which suffer from overgrowth, and to maintain the quality of other suitable sites that might increase the size of the existing subpopulations.
Implications for insect conservation
Our results show that
I. beybienkoi
is a short-distance disperser and wanders only within its optimal habitat. Hence, to incorporate movement behaviour into conservation, one of the measures that should mitigate this threat is to preserve or improve the quality of habitats that suffer from overgrowth, in order to increase the size of existing subpopulations. The observed movement patterns suggest that the species is probably incapable of responding to changes in the availability of suitable habitats by dispersing, indicating a limited exchange of individuals between isolated populations. Thus, to enhance structurally diverse mosaic of high-quality habitats, restoration of migration corridors former used as movement corridors for grazing animals may support the dispersal of the threatened bush-cricket.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The composition of spider communities in forests is affected by habitat characteristics, such as canopy openness, vegetation cover or tree species diversity; therefore, we assume that the effect of ...canopy will differ among tree species.
As research in European beech forests has not been conducted, we studied the effect of understory environmental characteristics associated with a gradient of overstory canopy openness in beech forest on ground‐dwelling spider richness, abundance and guild composition in the Western Carpathians, Slovakia. Canopy openness, the cover of understory vegetation and litter, litter thickness and variability and soil reaction were recorded. In total, 17 332 individuals of 174 spider species were trapped during 518 days. We used Generalised Linear Models to explain the effect of environmental characteristics on the assemblages of ground‐dwelling spiders; the unique and shared contributions of the predictors were calculated using variation partitioning.
The association of canopy openness with spider species richness was hump‐shaped and displayed positive linear relationship with abundance. Abundance was also affected by soil pH.
The composition of spider communities was significantly affected by canopy openness and understory characteristics; a major part of this variation was shared between all variables. The guild composition of the assemblages interacted with canopy openness, as sheet‐web weavers were dominant under the most closed canopy, that below 20% of canopy openness, while ground hunters dominated in the rest of the canopy gradient.
The gradient of beech forest canopy openness affected spider species richness, abundance and guild composition and supported distinct assemblages.
Species richness of ground‐dwelling spiders in European beech forests was more strongly associated with canopy openness or understory vegetation cover than their activity density.
Canopy openness, cover of understory vegetation, characteristics of litter, soil pH and plot identity explained 62.6% of variation in spider communities' composition; however, a major part of this variation (39.8%) was shared between these explanatory variables.
Guild of sheet‐web weavers were dominant under the most closed canopy, while ground hunters dominated in the rest of the canopy openness gradient.
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BFBNIB, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
1. Phenotypic plasticity and/or genetic adaptation may allow species to live in a variable environment. It has been shown that eggs of the dark bush‐cricket, Pholidoptera griseoaptera, which ...experienced an insufficient warm treatment (shorter and/or colder), had a longer development time and hatched predominantly after the second diapause.
2. Given the broad distribution of this species from sea level to the timber line, we expected variation in voltinism along a climatic gradient. To reveal the role of natural selection in egg‐hatching patterns, we compared different and unrelated populations sampled along a 1000 m elevational gradient in a common laboratory experiment.
3. In the same rearing microclimate, we found that populations from mountains had mostly a shorter life cycle, whereas semivoltinism prevailed in lowland populations.
4. This demonstrated the genetically underpinned local adaptation of this insect to harsh mountain environments with a shorter growing season determined by elevation.
Egg hatching pattern of bush‐cricket Pholidoptera griseoaptera populations sampled along a 1000 m elevational graident was studied in a common laboratory environment.
Development rate of embryos increased with elevation of parental population, thus in lowland populations it took longer to hatch after being exposed to warm temperatures, than in populations from highlands.
This suggests the genetically underpinned local adaptation of this insect to a shorter growing season in a harsher mountain environment.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Abstract
The first biogeographical division of the Carpathians, the second largest mountain range in Europe, was based on qualitative observational floristic data > 100 years ago and has also been ...applied for the regional zoogeography. In this study, the recent availability of detailed quantitative data allowed us to perform a more powerful evaluation of the classical biogeographical regions of the area. Thus, we analysed updated distribution patterns of 137 Orthoptera species native to the Carpathian Mountains and, by using published species range maps, we compiled data on species presence or absence within 2576 cells of a 10 km × 10 km universal transverse mercator grid in the area. Pattern analysis of the data was based on non-metric multidimensional scaling and clustering using six different algorithms applied to a β sim dissimilarity matrix. The unweighted pair-group method using arithmetic averages, which gave the best performance in the analysis of species turnover, delineated four regions. Environmental variables and species richness were used in logistic regression as predictors of delineated clusters, and indicator species were identified for each of the inferred regions. The pattern can be explained, in part, by environmental variables and species richness (34.2%) and was also influenced by connections with the orthopterofauna from adjacent areas. The observed discrepancy between regionalization based on expert knowledge and the pattern revealed using quantitative data provides a warning that the biogeography of the Carpathians might also have been revised in other taxa, where only classical qualitative regionalization exists.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Abstract
Forest disturbances are intensifying globally, yet regional drivers of these dynamics remain poorly understood. We investigated recent disturbance intensities in Norway spruce (Picea abies ...L.) forests in Slovakia (Central Europe) with different management objectives in 2000–2017 based on Landsat imagery. We focused on 122 strict reserves without any management, their actively managed surroundings (500 m and 2000 m buffers), and managed production forests beyond the buffer areas. We used generalized additive mixed models to test for differences in temporal trends of disturbance intensity among these management categories. We found that disturbance intensity was increasing in all management categories during the studied period. The increase was more pronounced in the managed forests (compound annual disturbance rate 1.76% year−1) and the 2000 m buffer (2.21% year−1) than in the strict reserves (0.58% year−1). The predicted cumulative disturbance during the 18-year period was 9.9% in the reserves and 30.5% in the 2000 m buffer. We found that forests in nature reserves can be more resistant to disturbances than forests managed for timber production, despite management efforts to control disturbances in managed forests. Our findings can help reconcile the different perceptions of natural disturbances and their management in Central Europe and support climate-adapted management strategies that consider natural disturbances as an indispensable component of ecosystem dynamics.
Reproductive interference can shape regional distribution patterns in closely related species, if prezygotic isolation barriers are weak. The study of such interaction could be more challenging in ...nuptial gift‐giving species due to the direct nutritional effects on both sexes of both species during copulation. We mapped the distribution of two sister bush‐cricket species, Pholidoptera aptera and Pholidoptera transsylvanica, at the northern margin of their overlapping ranges in Europe, and with a behavioral experiment, we tested the possibility of heterospecific mating. We found a very rare coexistence of species locally (0.5%, n = 391 sites) with mostly mutually exclusive distribution patterns, resulting in a mosaic pattern of sympatry, whereas they occupied the same climate niche in forest‐dominated mountain landscape. Over 14 days of a mating experiment with seven mixed groups of conspecifics and heterospecifics (n = 56 individuals in total), the number of received spermatophores per female was 3–6 in P. aptera and 1–7 in P. transsylvanica. In total, we found 8.1% of heterospecific copulations (n = 99 transferred spermatophores with genetic identification of the donor species), while we also confirmed successful transfer of heterospecific sperms into a female's reproductive system. Because bush‐cricket females also obtain required nutrition from a heterospecific spermatophylax what should increase their fitness and fecundity, we suggest that their flexibility to mate with heterospecifics is beneficial and drives reproductive interference. This may substantially limit the reproductive success of the less frequent species (P. transsylvanica), coupled with eventual detrimental effects from hybridization, and result in the competitive exclusion of that species from their areas of coexistence.
We found a very rare coexistence of Pholidoptera aptera and Pholidoptera transsylvanica with mostly mutually exclusive distribution patterns, whereas they occupied the same climate niche in forest‐dominated mountain landscape. Experimental trials revealed 8% of heterospecific copulations, while successful transfer of heterospecific sperms into a female's reproductive system was also confirmed. Because females also obtain required nutrition from a heterospecific spermatophylax, we suggest that this reproductive interference may result in the competitive exclusion of the inferior species from their areas of coexistence.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
During 2013-2017, assemblages of bush-crickets and grasshoppers were surveyed in two neighbouring flysch mountains - Čergov Mts (48 sites) and Levočské vrchy Mts (62 sites) - in northern part of ...Western Carpathians. Species were sampled mostly at grasslands and forest edges along elevational gradient between 370 and 1220 m a.s.l. Within the entire area (ca 930 km
2
) we documented 54 species, representing 38% of Carpathian Orthoptera species richness. We found the same species number (45) in both mountain ranges with nine unique species in each of them. No difference in mean species richness per site was found between the mountain ranges (mean ± SD = 12.5 ± 3.9). Elevation explained 2.9% of variation in site species richness. Elevation and mountain range identity explained 7.3% of assemblages composition. We found new latitudinal as well as longitudinal limits in the distribution for several species. Occurrence and distributional patterns of some noteworthy species (
Isophya stysi
,
Pholidoptera transsylvanica
,
Poecilimon schmidtii
,
Polysarcus denticauda
,
Pseudopodisma nagyi
,
Chorthippus tatrae
), as well as habitat specialists (
Chorthippus pullus
,
Tetrix tuerki
) are discussed.
The reproductive interests of females and males often diverge in terms of the number of mating partners, an individual’s phenotype, origin, genes, and parental investment. This conflict may lead to a ...variety of sex‐specific adaptations and also affect mate choice in both sexes. We conducted an experiment with the bush‐cricket Pholidoptera griseoaptera (Orthoptera, Tettigoniidae), a species in which females receive direct nutritional benefits during mating. Mated individuals could be assigned due to the genotype of male spermatodoses, which are stored in the female’s spermatheca. After 3 weeks of possible copulations in established mating groups which were random replications with four females and males we did not find consistent assortative mating preference regarding to body size of mates. However, our results showed that the frequency of within‐pair copulations (192 analyzed mating events in 128 possible pairwise combinations) was positively associated with the body size of both mated individuals with significant interaction between sexes (having one mate very large, association between body size and the number of copulations has weaken). Larger individuals also showed a higher degree of polygamy. This suggests that body size of this nuptial gift‐giving insect species is an important sexual trait according to which both sexes choose their optimal mating partner.
In mating experiment with the bush‐cricket Pholidoptera griseoaptera, we did not find consistent size‐assortative mating preference; however, our results showed that the frequency of within‐pair copulations was positively associated with the body size of both mated individuals with significant interaction between sexes. Larger individuals also showed a higher degree of polygamy.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
KEY MESSAGE : After controlling for the effects of size and light, partial regression revealed that height growth of common beech saplings was negatively affected by sapling age. Common beech (Fagus ...sylvatica L.) saplings were studied along gradients of light availability (4–82 % of full sunlight), initial size (9–290 cm), and age (2–25 years) to examine the interactive effect of these variables on saplings’ annual height growth. Although age was non-significant as a main effect in a linear model, sapling age had a significant interaction with the other variables. After controlling for the effects of size and light, partial regression revealed that height growth was negatively affected by sapling age. Observed growth decline in older common-sized saplings may be explained not as effect of age per se, but as indirect age-related effect probably induced through plastic response of saplings to past growth conditions.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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