Insect Communities

Global study on the forest diversity and its drivers

The number of tree species in local ecosystems is a key measure of biodiversity. A well-known ecological rule states that species numbers increase from the poles to the equator. But why is this trend not completely universal, and what can influence local biodiversity? The scientific journal Nature Ecology and Evolution has just published a study that, by analysing an unrivalled database, compared the species richness of forests across virtually the entire planet and shed light on the reasons responsible for differences in tree diversity in different places. An international consortium of 249 authors from 50 countries collected data on more than 55 million trees in 1.3 million study plots, representing 97% of the world’s forest ecosystems. As the authors of the study point out, the collection of this amount of data and subsequent analysis was made possible not only by the collaboration of a large number of scientific capacities from different countries and institutions, but also by the participation of scientists from otherwise overlooked tropical areas. Our group confirmed by data from Mount Cameroon.

Press release:

Full citation: Liang J. et al. (incl. Delabye S., Janeček Š., Klomberg Y., Maicher V., Tropek R.) (in press) Co-limitation toward lower latitudes shapes global forest diversity gradientsNature Ecology & Evolution.

A call for a Ph.D. student in our group!

For a project entitled Latitudinal patterns in specialization of wild bees: Metabarcoding of pollen loads along a cross-continental gradient, we are seeking a highly motivated Ph.D. student. It combines modern Next Generation Sequencing metabarcoding of pollen loads from wild bees, the most important pollinators in terrestrial ecosystems, with a standardised observational sampling of interactions at a whole-community level. The material and data are sampled at seven localities along the cross-continental (Africa and Europe) latitudinal gradient. The length of the study is 4 years and the position starts in October 2022.

The position will be co-funded by the STARS program ( of the Charles University, and by a project awarded to Dr. Robert Tropek (supervisor) by the Czech Science Foundation. !! Deadline 13th March 2022 (no possibility for extensions…). The complete call is here: 

Three new graduates in our group!

Last week, three of our students successfully completed their degrees at the Charles University. Dominik Anýž and Jan (Honza) Filip have been awarded by MSc degrees for their theses in pollination ecology at the Department of Ecology. Dominik has performed preliminary analyses on patterns in plant reproduction strategies along elevation in Afromontane grasslands on Mount Cameroon. Because of covid difficulties, his data have still not been final and we will finish the sampling in November. Honza’s thesis stayed in Czechia, as he focused on the role of hoverflies in pollination networks of the Železné hory Mts. Václav Koďousek has defended his BSc thesis at the Institute for Environmental Studies. In his BSc thesis, he has reviewed the available information on effect of fires on butterflies and moths. We are also extremely happy that all three will continue working with us, Václav as a Master’s student, whilst Dominik and Jan as our newest Ph.D. students. Congratulations to all of them, and best of luck for their journeys ahead!


Summer sampling of plant-pollinator networks in Norway

After successfully sampling at Milovice despite the interfering wildlife, we continued fieldwork for our project focused on latitudinal trends of plant-pollinator interactions. This time, six team members drove to northern Norway to sample at the northernmost site in the project (and to experience the midnight sun!). Four days and six countries later, we made it to Sommerdalen in Borselv, where we spent the next three weeks setting up cameras, collecting nectar, and measuring flowers, among many other kinds of data. We studied various aspects of the pollination systems of 24 flowering plant species, some even growing in bogs. Unlike in Milovice, the animals left our cameras in peace, and we wrapped up fieldwork without a hitch. We shall return here in the the subarctic spring to finish the sampling and to take in more of the beautiful Norwegian landscapes!

Photo collage from Norway: clockwise from top left: a view of one of the sampling plots, a butterfly feeding on a flower, the team on a gorge, a bumblebee feeding on a flower

Sampling of plant-pollinator networks in Milovice

After many months of computer work, we have enjoyed almost the entire May in the field. We have started a large project recently supported by the Czech Science Foundation (Junior Star project, PI-ed by Rob), focused on latitudinal trends of plant-pollinator interactions as sampled at seven localities from South Africa to northern Norway. The pandemics has slightly postponed the project beginnng, so we have started in Czechia, in the adandoned military training area of Milovice, recently rewilded by European bisons, aurochs and wild horses (more details in Czech and some pictures here: Virtually the entire team has optimised all sampling protocols to get prepared for the future abroad localities. We have also sampled various data on pollination systems of ~40 currently flowering plant species, despite the ‘sub-optimal’ in many days, and the wild horses loving to play with our camera systems. It was very nice to be in the field, especially in such nice and diverse piece of nature!

Three new doctors in our group!

In the past two weeks, three of our members defended their Ph.D. theses! (Isn’t this some kind of record?!) First, Sylvain defended his thesis on biodiversity of Afrotropical butterflies and moths at the University of South Bohemia, Czechia. The next week, Mercy has defended her thesis on fruit-feeding butterflies on Mount Cameroon at the University of Buea, Cameroon. And just a few days later, Yannick defended his thesis on plant-pollinator interactions at the Charles University, Czechia. We all are very proud, all three theses brought a lot of interesting results and even more fun. Congratulations, Dr. Murkwe, Dr. Delabye and Dr. Klomberg!


New research sites in Krkonose montane grasslands

Štěpán and Antigone identifying flowering herbs.

As a conclusion to the busy month, a large part of our team (Rob, Stepan, Kobe, Antigone, Dominik and Sailee) spent the last week of June in the Krkonose mountains. We hiked along the ridge of the mountain range, looking for suitable areas to study pollination networks with the Czech Science Foundation (GAČR) project PI-ed by Rob. As opposed to our spring sampling in the semi-natural forests, we were scouting for natural grasslands above the timberline. All throughout (minus a foggy day), we hiked through beautiful landscapes and fair weather.With Stepan and Antigone proceeding at “botanical” pace, we spotted numerous interesting plant species, some of them endemic! Not surprisingly, there were plenty of insects too. Our trip has been highly successful, and we now have a few potential sites to choose from for our longer sampling sessions next summers!

Field courses for students in Czechia

June has been a rather busy month! We’ve been on and off field quite a bit, but we have also did some field teaching of ecology. In early June, Kobe and Sailee assisted with teaching a field course of the Department of Ecology, Charles University, for bachelor’s students in Lomy u Kunžaku, South Bohemia. Despite the frequent spells of rain, the students made the most of the course and learnt basic insect sampling techniques among other things. In mid-June, they also helped with a field course of the Plant-Animal Interactions lectures for MSc and PhD students of the University of South Bohemia in Holubov, South Bohemia. The more specific focus of the course helped students learn about pollination biology, ant-plant mutualisms and herbivory. Assisting with these courses has been rather rewarding to Kobe and Sailee; teaching concepts to students has helped reinforce ideas and notice gaps in understanding. We look forward to more of such opportunities!

Sailee (under Stepan’s supervision) is helping students to measure floral colours by a spectrometer during the field course.

Spring sampling in the Krkonoše Mts.

During May, our group (mainly Sailee, Kobe, Antigone and Eliska, but with a strong support of many others) resumed sampling in the Krkonoše Mts. in northern Czechia. We recorded floral visitors of plants in semi-natural forests along their altitudinal gradient. For comparability, we followed our protocol from Mount Cameroon. Having sampled lower elevations in the last year, we moved on to two higher elevations this spring. The fieldwork was interrupted by snow, which led to some mixed reactions from us. Fortunately the spring insects weren’t affected much, and we finished sampling successfully. Although we’ve got a lot of desk work ahead of us, our sampling in the forests of Krkonoše is complete!

Snapshots from Krkonoše: Some of the species we recorded, our study area, and our team.


Popularising of our research

Štěpán being interviewed in Krkonoše.

In the past months, our research has repeatedly appeared in media, especially in Český rozhlas Plus, the Czech public radio focused on science and society. Our last sampling trip to Kruger NP was accompanied by a journalist Ondřej Novák who recorded rich material. Mainly, it resulted in an episode of the Adventure of Science, a series specialised on international research of Czech Scientists. Some additional material from Kruger was used for three (1, 2, 3) episodes of the Natura broadcast dissecting particular aspects of our work, as well as biodiversity and protection of African savanna. Ondřej Novák also accompanied us to our fieldwork in Krkonoše where he recorded a long interview with Robert on ecological and evolutionary aspects of pollination interactions. Our research has appeared also in a broadcast on biological research in the Krkonoše NP. Last but not least, Robert also gave an interview on urban biodiversity in Prague, including its efficient protection. It is always fun for us to participate on popularising of ecological knowledge in media. (Unfortunately, all above-mentioned broadcasts and interviews are in Czech.)