Robert Tropek

Charles University in Prague | CUNI

Elevated environmental levels of elements originating from anthropogenic activities threaten natural communities and public health, as these elements can persist and bioaccumulate in the environment. However, their environmental risks and bioaccumulation patterns are often habitat-, species- and element-specific. We studied the bioaccumulation patt...

Deposits of fly ash and other coal combustion wastes are common remnants of the energy industry. Despite their environmental risks from heavy metals and trace elements, they have been revealed as refuges for threatened terrestrial biodiversity. Surprisingly, freshwater biodiversity of fly ash sedimentation lagoons remains unknown despite such lack...

Africa has undergone a progressive aridification during the last 20 My that presumably impacted organisms and fostered the evolution of life history adaptations. We test the hypothesis that shift to living in ant nests and feeding on ant brood by larvae of phyto-predaceous Lepidochrysops butterflies was an adaptive response to the aridification of...

Bergmann's Rule describes an increase in the body size of endothermic animals with decreasing environmental temperatures. However, in ectothermic insects including moths, some of the few existing studies investigating size patterns along temperature gradients do not follow the Bergmann's Cline. Intraspecific differences in moth sizes along spatiote...

Environmental productivity, i.e., the amount of biomass produced by primary producers, belongs among the key factors for the biodiversity patterns. Although the relationship of diversity to environmental productivity differs among studied taxa, detailed data are largely missing for most groups, including insects. Here, we present a study of moth di...

Background Thanks to the high diversity of ecosystems and habitats, South Africa harbours tremendous diversity of insects. The Kruger National Park, due to its position close to the border between two biogeographic regions and high heterogeneity of environmental conditions, represents an insufficiently studied hotspot of lepidopteran diversity. Dur...

The latitudinal diversity gradient (LDG) is one of the most recognized global patterns of species richness exhibited across a wide range of taxa. Numerous hypotheses have been proposed in the past two centuries to explain LDG, but rigorous tests of the drivers of LDGs have been limited by a lack of high-quality global species richness data. Here we...

• Nectar robbing and thieving can substantially affect the reproduction of animal pollinated plants. Although the intensity of nectar exploitation remains unexplored at the community level, it probably varies along environmental gradients. • We video-recorded flower visits to animal-pollinated plants in Afrotropical rainforests along a complete el...

To identify factors that drive plant species richness in South-African savanna and explore their relative importance, we sampled plant communities across habitats difering in water availability, disturbance, and bedrock, using the Kruger National Park as a model system. We made plant inventories in 60 plots of 50 × 50 m, located in three distinct h...

The pollination syndrome hypothesis predicts that plants pollinated by the same pollinator group bear convergent combinations of specific floral functional traits. Nevertheless, some studies have shown that these combinations predict pollinators with relatively low accuracy. This discrepancy may be caused by changes in the importance of specific fl...

Deposits of coal combustion wastes, especially fly ash, are sources of environmental and health risks in industrial regions. Recently, fly ash deposits have been reported as habitat surrogates for some threatened arthropods in Central Europe. However, the potential environmental risks of fly ash have not yet been assessed in the region. We analysed...

1. Post-mining freshwater habitats can serve as secondary habitats for threatened species. Being globally plentiful, their efficient restoration should be based on detailed evidence, especially under the current global decline of freshwater biodiversity. Synthetic studies focusing on the effects of restoration on freshwater communities are surprisi...

Many tropical plants are pollinated by birds and several bird phylogenetical lineages have specialised to a nectar diet. The long-assumed, intimate ecological and evolutionary relationship between ornithophilous plants and phenotypically specialised nectarivorous birds has nevertheless been questioned in recent decades, where such plant–pollinator...

Despite a growing number of studies, the role of pollinators as a selection agent for nectar traits remains unclear. Moreover, the lack of data from some biogeographic regions prohibits us from determining their general importance and global patterns. We analyzed nectar carbohydrate traits and determined the main pollinators of 66 plant species in...

Butterflies and moths are conspicuous flower visitors but their role in plant-pollinator interactions has rarely been quantified, especially in tropical rainforests. Moreover, we have virtually no knowledge of environmental factors affecting the role of lepidopterans in pollination networks. We videorecorded flower-visiting butterflies and hawkmoth...

Mechanisms structuring tropical communities are still under‐studied, especially in Afrotropical rainforests. Although insect herbivores are considered to depend on plant diversity, we hypothesized that vegetation structure, together with other microhabitat characteristics, can be more important for some insects. Here, we compared habitat associatio...

1. Butterflies and moths are well-visible flower visitors. Nevertheless, almost no quantification of their role in plant-pollinator interactions exists at a community level, especially from tropical rainforests. Moreover, we have virtually no knowledge on environmental and other factors affecting lepidopteran flower visits. 2. We focused on the ro...

Natural disturbances are essential for tropical forests biodiversity. In the Afrotropics, megaherbivores have played a key role before their recent decline. Contrastingly to savanna elephants, forest elephants' impact on ecosystems remains poorly studied. Few decades ago, forests on Mount Cameroon were divided by lava flows, not being crossed by a...

Southern Africa hosts a high diversity of ecosystems and habitats with a tremendous diversity of Lepidoptera. Although it is one of the most studied parts of the Afrotropics, the knowledge on diversity and distribution of south African moth fauna remains insufficient. To partly fill this gap, we surveyed macromoths by automatic light traps in five...

Background Phylogenetically closely related strains of maternally inherited endosymbiotic bacteria are often found in phylogenetically divergent, and geographically distant insect host species. The interspecies transfer of the symbiont Wolbachia has been thought to have occurred repeatedly, facilitating its observed global pandemic. Few ecological...

The pollination syndrome hypothesis predicts that plants pollinated by the same pollinator group bear convergent combinations of specific floral traits. Nevertheless, some studies have shown relatively low predictive power for these floral trait combinations. This discrepancy may be caused by changes in the importance of specific floral traits for...

In arthropod community ecology, species richness studies tend to be prioritised over those investigating patterns of abundance. Consequently, the biotic and abiotic drivers of arboreal arthropod abundance are still relatively poorly known. In this cross-continental study, we employ a theoretical framework in order to examine patterns of covariance...

Protected areas play an important role as refuges from invasive species impacts on biodiversity. Within the MOSAIK (Monitoring Savanna Biodiversity in the Kruger National Park) project, plant species were recorded in a representative set of 60 plots, 50 × 50 m in size, across the entire KNP, distributed so as to cover a range of savanna habitats, i...

Background Phylogenetically closely related strains of maternally inherited endosymbiotic bacteria are often found in phylogenetically divergent, and geographically distant insect host species. The interspecies transfer of the symbiont Wolbachia has been thought to have occurred repeatedly, facilitating its observed global pandemic. Few ecological...

Background Phylogenetically closely related strains of maternally inherited endosymbiotic bacteria are often found in phylogenetically divergent, and geographically distant insect host species. The interspecies transfer of the symbiont Wolbachia has been thought to have occurred repeatedly, facilitating its observed global pandemic. Few ecological...

Background Phylogenetically closely related strains of maternally inherited endosymbiotic bacteria are often found in phylogenetically divergent, and geographically distant insect host species. The interspecies transfer of the symbiont Wolbachia has been thought to have occurred repeatedly, facilitating its observed global pandemic. Few ecological...

Natural disturbances are essential for dynamics of tropical rainforests, contributing to their tremendous biodiversity. In the Afrotropical rainforests, megaherbivores have played a key role before their recent decline. Although the influence of savanna elephants on ecosystems has been documented, their close relatives, forest elephants, remain poo...

Mount Cameroon, SW Cameroon, has already been described as a unique hotspot of the many-plumed moth (Lepidoptera, Alucitidae), with their local diversity unrivalled in the entire Afrotropics. We confirm its importance with description of seven new species: Alucita bakweri Ustjuzhanin & Kovtunovich, sp. nov., Alucita jana Ustjuzhanin & Kovtunovich,...

The deficiency of pollen grains for ovule fertilization can be the main factor limiting plant reproduction and fitness. Because of the ongoing global changes, such as biodiversity loss and landscape fragmentation, a better knowledge of the prevalence and predictability of pollen limitation is challenging within current ecological research. In our s...

The pollination syndrome hypothesis has been under debate over the past decades. It is criticized as an oversimplification of complex interactions: its validity varies across plant families and depends on spatio-temporal variability of plant–pollinator interactions, yet exact patterns are unclear. We tested the pollination syndrome predictability i...

The biodiversity of West and Central Africa is understudied, including butterflies and moths (Lepidoptera). Cameroon, through its position in between few biogeographic regions and diversity of habitats, is an important hotspot of lepidopteran diversity. However, the country also ranks low when it comes to local biodiversity knowledge. During our lo...

Aim Temporal dynamics of biodiversity along tropical elevational gradients are unknown. We studied seasonal changes of Lepidoptera biodiversity along the only complete forest elevational gradient in the Afrotropics. We focused on shifts of species richness patterns, seasonal turnover of communities and seasonal shifts of species’ elevational ranges...

During extensive field research of fruit-feeding Lepidoptera in various West African forests, we have collected a rich material of several rare or poorly known species. Among them we identified four species, where only one of the sexes was described. Here, we describe unknown females of Euriphene lomaensis Belcastro, 1986, E. taigola Sáfián & Warre...

Research on canopy arthropods has progressed from species inventories to the study of their interactions and networks, enhancing our understanding of how hyper-diverse communities are maintained. Previous studies often focused on sampling individual tree species, individual trees or their parts. We argue that such selective sampling is not ideal wh...

Apart from floral morphology and colours perceived by the human eye, ultraviolet reflectance (UV) acts as an important visual advertisement of numerous flowering plant species for pollinators. However, the effect of UV signalling on attracting pollinators of particular plant species is still insufficiently studied, especially in the Afrotropics. Th...

Amerila is one of the most studied Afrotropical genera of Arctiinae. However, based on a regionally constrained sample of specimens from Mount Cameroon, we show how superficial our knowledge on these tiger moths is. Among six collected Amerila species, A. femina’s female is described here for the first time, and A. mulleri and A. roseomarginata had...

Apart from floral morphology and colours perceived by the human eye, ultraviolet (UV) reflectance acts as an important visual advertisement of numerous flowering plant species for pollinators. However, the effect of UV signalling on attracting pollinators of particular plant species is still insufficiently studied, especially in the Afrotropics. Th...

During extensive field work in West Africa (Cameroon, Ivory Coast, Liberia, Sierra Leone), the authors collected two skipper species in the genus Andronymus (Lepidoptera, Hesperiidae), which would not fit the descriptions of any existing taxa. Both are described as new, A. magma sp. nov. is known only from Cameroon, while A. fenestra sp. nov. was f...

Leptotina butterflies (Lycaenidae, Polyommatiinae) are found mostly in tropical and subtropical areas around the globe, marginally penetrating into temperate regions. Here, we investigated phylogenetic and biogeographical relationships of most representatives of the subtribe, using both likelihood and Bayesian approaches. We also estimated the timi...

Although seasonality in the tropics is often less pronounced than in temperate areas, tropical ecosystems show seasonal dynamics as well. Nevertheless, individual tropical insects’ phenological patterns are still poorly understood, especially in the Afrotropics. To fill this gap, we investigated biodiversity patterns of Lepidoptera communities at t...

Floral preferences of generalist foragers such as eusocial bees influence the success of pollination of many flowering plants, as well as competition with many other bee species in tropical communities. Eusocial bees are important for the pollination success of many flowering plants, as well as for food resources availability for many other species...

Fifteen species of many-plumed moths are recorded from the Mount Cameroon area, SW Cameroon, West Africa. Nine species: Alucitalongipenis Ustjuzhanin & Kovtunovich, sp. n. , A.lidiya Ustjuzhanin & Kovtunovich, sp. n. , A.ludmila Ustjuzhanin & Kovtunovich, sp. n. , A.escobari Ustjuzhanin & Kovtunovich, sp. n. , A.mischenini Ustjuzhanin & Kovtunovich...

Heterogeneity of environmental conditions is the crucial factor supporting biodiversity in various habitats, including post-mining sites. The effects of micro-topographic heterogeneity on biodiversity and conservation potential of arthropod communities in post-industrial habitats had not been studied before now. At one of the largest European brown...

Post-industrial sites, including fly ash deposits, are common landscape components in many Central European regions. Their effective restoration is thus crucial because such habitats have been recognised as critical secondary refuges for many endangered and declining species. Controversially, the overwhelming majority of restoration projects consid...

Mining activities, specifically open cast mining, generate massive ecological damage. However, recently it has been demonstrated that unreclaimed post-mining sites can provide valuable habitats for many rare and endangered species and hence are more favored rather than the reclamation approach. Yet, the species diversity and its related variability...

Post-mining sites often offer secondary habitats for various amphibians endangered in common agricultural landscapes. On the other hand, there is a general lack of quantitative studies on the effects of the common restoration practices on colonisation of such artificial freshwater habitats by amphibians. Here, we focus on two newts decreasing in Ce...

The marbled crayfish (Procambarus fallax f. virginalis) has become one of the potentially most dangerous non-indigenous crayfish species spreading in European countries and elsewhere. This taxon reproduces parthenogenetically and recently has been verified as a vector of the crayfish plague pathogen. Here, we report on two established populations o...

Temperate open woodlands are recognized as biodiversity hotspots. They are characterised by the presence of scattered, open-grown, often old and large trees (hereafter referred to as ‘‘solitary trees”). Such trees are considered keystone ecological features for biodiversity. However, the ecological role of solitary trees and their importance for wo...

The damselfly Coenagrion ornatum is a threatened species, specialized for lowland headwater streams. As the species is declining and protected across Europe, it represents a species of particular conservation interest. This work aims to provide the first evaluation of fine-scale spatial ecology in this species, especially to assess its general mobi...

The damselfly Coenagrion ornatum represents a threatened species of lowland headwater streams. Although the species is threatened in Western and Central Europe, it is known at a system of post-mining drainage ditches in the Radovesicka spoil heap (northwestern Bohemia, Czech Republic). This study aimed to estimate its population size in this post-m...

During our surveys of fruit-feeding Lepidoptera at the Mount Cameroon National Park and the Bimbia Bonadikombo Community Forest (both southwestern Cameroon) we recorded nineteen species of Erebidae moths not previously reported from Cameroon. Simultaneously, we provide the first records of genera Ametropalpis and Lacera from the country.

A field survey of Mount Cameroon, SouthWest Province, Cameroon, revealed two butterfly species new to science. Lep-idochrysops liberti sp. nov. (Lycaenidae) flies in the extensive mosaic of natural clearings in sub-montane forest above 1100 m a.s.l., whereas Ceratrichia fako sp. nov. (Hesperiidae) locally inhabits the forested narrow gullies in the...

Open interior sands represent a highly threatened habitat in Europe. In recent times, their associated organisms have often found secondary refuges outside their natural habitats, mainly in sand pits. We investigated the effects of different restoration approaches, i.e. spontaneous succession without additional disturbances, spontaneous succession...

Headwaters and small streams are crucial components of riverine systems, harbouring many highly specialized and unique invertebrate species. Unfortunately, the overwhelming majority of the Central European lowland headwaters are channelized, eutrophicated and/or polluted, and many related species have become critically endangered. Artificial stream...

We present new information about distribution of the following species: Chrysidoidea: Chrysididae: Chrysis clarinicollis Linsenmaier, 1951. New species for Moravia and confirmed occurrence in Bohemia. Chrysis comta Förster, 1853. New species for Moravia. Chrysis corusca Valkeila, 1971. New species for the Czech Republic. Chrysis gribodoi gribodoi A...

The species Hypolycaena anara Larsen, 1986, is reported as a new record for Cameroon, together with a description of two new montane localities. We also describe two previously unpublished localities of the species in Nigeria. Potential contribution of the discovery of this hilly-savannah butterfly in the Gulf of Guinea Highlands to the recent deba...

The degree of specialization in plant–pollinator relationships is probably the most intensively discussed topic of pollination biology. Phenotypically generalized flowers are typically also considered to be generalized ecologically and/or functionally. Our study focuses on visitors to flowers of Hypericum roeperianum and H. revolutum, two closely r...