The MountBuzz Borneo team 2026 consisted of Andrea Errante – his third trip within the MountBuzz project now! – Julian Gericke, Isabella Fresner and Hong Chen. They were further accompanied by PAIn lab member Ben Lazarus, who introduced the team to artificial vibration experiments and single visit experiments with bees. The team was lucky in finding many species in flower, but unlucky with equipment failure. The air particle counters we use for pollen counting stopped working – despite having worked perfectly fine when tested the day before departure in the lab. The team readjusted the fieldwork plan somewhat, decided to use an alternative method for pollen collection (in Eppendorf tubes) and further refined the single visit experiments test stand! Julian in particular turned out to be a bee whisperer and just recently surpassed the 200^th single bee visit, for which he also obtained accurate bee size measurements and audio recordings! Another great surprise for the team waited at one of our lower elevation sites – while in 2025, the team could only locate a single species in flower (Melastoma malabathricum), this time, they found three other species in full flower, covering tribes that we had not sampled previously! Discoveries like those show how valuable it is for us to go back to the same field sites at different times, because they might hold treasures previously unnoticed! Congratulations to the whole team for working through many challenges and keeping up the spirit!

Lalaina and Tsito from our Madagascar MountBuzz team had just finished their first year of data collection in December 2025, when starting to make plans to go back to the field in February 2026. The reason was that during the October-December fieldwork, while highly successful for finding certain genera such as Medinilla in flower, few species of the genus Gravesia flowered, and especially few at the lowest elevations. Because we need assessments of plant-pollinator interactions across the entire elevational gradient, capturing the low elevation species is equally important as capturing the high elevation species. For this reason, Lalaina and Tsito went back to the field for another month and conducted a highly successful fieldtrip, finishing pollinator observations at low elevations, with many different bee species visiting the available Gravesia flowers! They further had a chance to monitor flower and fruiting phenology, adding to the dataset collected last year, and revealing exciting patterns of stacked flowering of different Melastomataceae genera. Hiking back up to the summit further allowed them to evaluate the results of the hand pollination treatments performed by Andrea and Gregor in 2025. Lalaina and Tsito are now busy reviewing the pollinator video data collected in 2025 and 2026 to estimate flower visitation rates, as well as working on bee identifications. If all goes well, they will visit the PAIn lab at the University of Vienna later in 2026 to work on pollen counting and complete datasets for their respective PhD projects on Medinilla and Gravesia.

In late March 2026, the MountBuzz Brazil team wrapped up fieldwork in the Atlantic Forest in Eastern Brazil, where they had spent three months revisiting sites we had worked at in 2025, and scouting for a few new sites and species. Throughout the fieldwork, the team struggled with heavy rainfalls and bad weather – which also, on the other hand, led to several exciting discoveries, such as that it is literally impossible to extract pollen through mechanical vibrations from Melastomataceae anthers when it is rainy. Likely, this inability to extract pollen comes from humidity-induced clumping of pollen grains, and makes it even more understandable why bees don’t forage under these rainy conditions! This second year’s fieldwork was structured around filling small gaps in the dataset collected last year, but primarily oriented towards new experiments, particularly single-visit pollination experiments with different bees. In single visit experiments, a previously unvisited flower is made available to a single bee visit only, and then collected in order to count pollen grains deposited on the stigma, and pollen remaining in the anthers. We will compare the remaining pollen to pollen available in unvisited flowers to obtain a measure of how much pollen the bee has removed. For these experiments, we have developed a novel test stand where we fix the flower in a standardized way and connect it to a piezo-microphone with which we can measure the tissue-borne vibrations. Amongst other things, we hope to obtain reliable measurements of vibration amplitude, which generally cannot be measured accurately under field conditions. Apart from single-visit experiments, the team was also busy performing artificial vibration experiments for as many species as possible to explore how morphologically distinct species release pollen when exposed to the full spectrum of the bee-vibration parameter space. César, who led the fieldwork, is getting ready to present preliminary findings at several conferences later this year, including the 6^th Pollination Biological Symposium in Brazil in August, the 13^th Colombian Botanical Congress in October, and the 40^th SCAPE meeting in Sweden in October! If you are going to any of these conferences, make sure you get to listen to his talk! =)

In early September, the MountBuzz Ecuador team united in Ecuador, consisting of César Arvelos and Juliane Nazari-Montazer (University of Vienna), Laura Lopresti (James Cook University, Australia), and Madelén Quistial and Juan Carlos (INABIO, Ecuador). During the first weeks, the fieldwork team was joined by Diana Fernández-Fernández and Agnes Dellinger for an exploration trip to all the study sites. At first, we thought we were only going to find fruits… Diana had visited the area a few months prior (July) and found many Melastomataceae species with flowers – understanding phenological patterns still is a major challenge in tropical ecosystems, and obviously, Agnes’ observations from her PhD did not fully match up – Agnes had worked in the same area during her PhD and normally found many species in flower in the months between September and November. Eventually, however, more intense explorations paid off, and the team could locate good areas with many flowering Melastomataceae, such as in the few remnant rainforests in the Chocó. The trip to the Chocó, coming from the high Andes and cloud forests around Quito, was particularly impressive, troublesome and thought-provoking. The Chocó is one of the most biodiverse (and wettest!) areas of our planet, yet has suffered from intense deforestation, which we could unpleasantly testify when driving through barren grasslands where only about 30 years ago, there had been pristine primary rainforests. For the trip to the Chocó, we were joined by our long-term friend and colleague Pancho Sornoza, bird specialist and conservationist in Ecuador, who had been instrumental in preserving some of the remaining forest patches of the Ecuadorian Chocó. Waking up to the calls of howler monkeys and falling asleep to a tropical frog concert, getting a glimpse of ice shields of the majestic Cayambe volcano when the cloud forest clouds lifted for a moment, and watching many buzzing bees on Melastomataceae flowers certainly stick out as highlights from the exploratory trip.

After settling on the field sites, we started training and data collection in the high elevation cloud forests, and were immediately rewarded by exciting discoveries. Besides the bee-pollinated Melastomataceae, we could record new instances of pollinator shifts to vertebrate pollinators, namely hummingbirds and bats, by putting up cameras during day and nighttime. We further performed a range of manual pollination experiments to understand whether reproductive strategies of Melastomataceae change to reproductive autonomy at high elevations (where bee pollination is often limited by adverse weather conditions). At this point, also a big shout out to the Ecuador team – this type of fieldwork is all but easy, and besides harsh conditions during work in the field, living conditions may also be harsh – like sleeping in a tent on a cold stone floor at 3000 masl. The upside: a bucket-shower under the starry sky 😉