The transfer involved 35 adults—two males and 33 females—collected in June 2002 from a mountain population in the Türnitz Alps and transferred to Nové Údolí in Šumava National Park. The release site was approximately 160 aerial kilometres from the source and contained grasslands and fens in which the butterfly’s principal larval host, Bistorta officinalis, was dominant. Butterflies remained near the release patches for three years before expanding into adjacent grasslands. A mark-recapture study in 2011 and 2012 estimated about 110 adults in three hectares of patches and found records up to 900 metres from the release point.

For the 2023 study, the authors surveyed all identifiable grassland and fenland patches around Nové Údolí, along the Studená Vltava River, beside Hraniční potok, near the Czech-German border and around Stožec and Černý Kříž. Surveys were conducted from June 1 to 10 during suitable butterfly activity. Each of the 212 patches, with a combined area of 285.7 hectares, was visited once and surveyed along a zigzag route. Presence was recorded as present or absent, while abundance was assigned to an ordinal scale from one individual to more than 20.

During the survey, the authors made 557 observations of L. helle. The butterfly was concentrated around the former Nové Údolí village, along the Studená Vltava River and near Spálený luh bog. Records became less frequent northward, and the most distant observation was 4,210 aerial metres northwest of the release point. The species was not detected in the surveyed fenlands around Stožec or Černý Kříž, which were separated from the occupied range by extensive mature spruce forests.

Principal-component analysis associated butterfly presence and abundance with wet, relatively impenetrable and unmanaged grasslands, generally on flat terrain with closed edges and substantial Bistorta cover. Regression models produced similar associations. Presence and abundance generally increased with wetness, closed habitat edges and host-plant cover, and declined with active management, slope, cloud cover and wind. Bistorta officinalis covered a mean 49.6% of occupied patches, compared with 23.4% of unoccupied patches, although the observed values varied substantially among patches.

The habitat associations were consistent with reports from other populations of L. helle in Central and Western Europe. The butterfly was most closely associated with waterlogged grasslands in an advanced stage of succession, where B. officinalis remained abundant but woody encroachment had not eliminated the host plant. Regular mowing or grazing tended to reduce the host plant, whereas complete abandonment could allow taller grasses, sedges and woody vegetation to dominate. The survey therefore identified a narrow habitat window rather than a simple association with either management or abandonment.

The 2023 observations do not directly establish the total adult population because abundance was scored ordinally rather than counted at every patch. The authors extrapolated an estimate of approximately 2,400 adults by applying the earlier 2011–2012 estimate from a smaller, high-density area to the 66.6 hectares occupied in 2023. They explicitly cautioned that this figure may be inflated because the earlier mark-recapture survey sampled dense patches. The more direct evidence was the recording of more than 500 individuals during the 2023 survey and the substantially larger occupied habitat area than in the earlier assessment.

The occupied range expanded from a most distant record of 900 metres after the first decade to 4,210 metres after two decades. This corresponds to an average expansion rate of 0.1 kilometres per year during the first decade and 0.2 kilometres per year over the full 20 years. The authors estimated that the Šumava population expanded more slowly than translocated L. helle populations in France, where rates of 0.52 kilometres per year in Morvan and 0.45 kilometres per year in Forez were reported. Available genetic-heterozygosity measurements did not support genetic impoverishment as the explanation for the slower expansion.

This observational field study has several bounded limitations. Each patch was visited only once during the species’ short adult flight period, so variation among survey dates and weather conditions could affect presence and ordinal abundance estimates. The study covered a defined landscape around the release area rather than the species’ complete European distribution, and it did not directly measure total adult numbers in 2023. Its findings indicate that the transferred population was established and expanding across suitable grasslands, while also showing that it had not crossed the surrounding continuous forest barriers during the study period.

Subject of Research: Field assessment of the distribution and habitat associations of a translocated Violet Copper population in the Šumava Mountains

Article Title: Population status of the highly endangered Lycaena helle ( Papilionoidea , Lycaenidae ) in the Šumava Mts. two decades after establishment

Article References: Peškařová, T., Pavlíčko, A., Kuras, T., Fric, Z. F., & Konvička, M. (2024). Population status of the highly endangered Lycaena helle (Papilionoidea, Lycaenidae) in the Šumava Mts. two decades after establishment. Nota Lepidopterologica, 47, 171-186. https://doi.org/10.3897/nl.47.126025

Image Credits: AI Generated

DOI: 10.3897/nl.47.126025

Keywords: Violet Copper, Lycaena helle, species translocation, Šumava Mountains, butterfly conservation, habitat selection, grassland management, population monitoring, Czech Republic, Population, status, highly

Aposematic colouration is associated with animals that are unpalatable, toxic or otherwise dangerous, and can take the form of conspicuous contrasting colours such as black with yellow or red. Among bees and wasps, aposematic signals are associated with the sting, although some non-stinging groups can also display warning-like coloration. The survey classified patterns into four categories: black-and-yellow, including white or creamy white; black-and-red; black-yellow-red; and metallic. The first three were pigment-based, whereas metallic coloration arose through physical effects within the insect cuticle.

The study examined the fauna of the Czech Republic, which the authors described as rich in the groups considered and representative of the European fauna for them. Its principal subject was Hymenoptera: Aculeata, or bees and wasps, with the families Bethylidae, Dryinidae, Embolemidae and Formicidae excluded because they have different life strategies. The three main mimic groups were clearwing moths in Lepidoptera, hoverflies in Diptera and longhorn beetles in Coleoptera. Species lists were drawn from established regional faunas for bees, wasps and each mimic group.

Colouration was assessed separately for males and females using the first author’s private collection, the National Museum in Prague and major online photographic resources, including iNaturalist, Flickr and Biolib. A species was recorded as aposematic when it possessed one of the four designated pattern types, with records made for body colour and body hairs. Bands of yellow or white hairs counted as aposematic patterns, as did combinations of black and red body colour with white hairy spots or bands. When males and females differed in colouration, the researchers entered half of each pattern for that species in the dataset.

Clearwing moths had the highest proportional representation of aposematic species in the comparison, with 36 of 43 species, or 83.72%. Hoverflies followed with 322 of 424 species, or 75.94%. Longhorn beetles had a lower overall prevalence, with 104 of 205 species, approximately 50.73%, displaying aposematic coloration. Despite these differences, black-and-yellow was the most frequent pattern in each of the four groups. It appeared in 271 of the 322 aposematic hoverflies, or 84% of that aposematic subset, and in 51% of the aposematic longhorn beetles recorded in the analysis.

The other patterns were less common overall but had distinctive distributions. Black-and-red coloration accounted for 23% of aposematic longhorn beetles, the highest proportion among the groups, compared with 8% of aposematic hoverflies. Metallic coloration was also relatively prominent in longhorn beetles, reaching 22% of their aposematic species. Among the bees and wasps, bees included 433 aposematic species, representing 71% of the bee species analyzed, and black-and-yellow was especially prominent among non-parasitic bees. In many of those species, the pale component of the pattern was produced by bands or spots of body hairs rather than pigmented skin.

Family-level comparisons revealed still greater concentrations of particular signals. Every cuckoo wasp in the family Chrysididae had metallic coloration and no other recorded aposematic type. Black-and-red was strongly represented in spider wasps, Pompilidae, while black-and-yellow predominated in Vespidae. Black-yellow-red coloration was more prevalent in Mutillidae. On average, the aposematic share of species in Chrysididae was only slightly above half that of Apoid wasps, which comprised 165 of 281 species, or 58%. These contrasts show that a broad survey category can conceal sharply different colour patterns among related insect lineages.

Foraging strategy also corresponded with differences in warning coloration. Nesting predators and nesting herbivores had similar proportions of aposematic representatives, while 96% of the parasitic species examined used aposematic signals frequently. Almost 87% of breeding herbivores had black-and-yellow coloration, whereas that pattern occurred in only 21% of parasites. Metallic coloration was the most common pattern among parasites at 34%, but the authors noted that this result was driven by cuckoo wasps. With Chrysididae excluded, metallic coloration was absent from the other parasitic species, and the three pigment-based patterns were approximately equally common, each accounting for between 32% and 40%.

Males and females differed in coloration in 67 of the 1,221 bee and wasp species, or 5.49%. One recurring arrangement involved females with white hair bands that were absent or less pronounced in males, as in several Andrena and Eucera species. More pronounced differences appeared in the cuckoo bees Ammobatoides abdominalis and Epeoloides coecutiens, whose males were cryptically coloured while their females had aposematic black-and-red patterns with white markings. Several Mutillidae and Pompilidae also combined aposematic females with entirely black males. In some Mutillidae, the difference coincided with wingless females and winged males, although the survey did not experimentally test the function of the dimorphism.

Sex-related differences also appeared among the mimics. Twenty-six hoverfly species showed some distinction between the sexes, usually the absence or reduction of yellow or red markings in males. Eight longhorn beetle species differed, and in most of them males were cryptically coloured while females were aposematic. Tetropium castaneum showed the reverse pattern, while the male Oxymirus cursor was black and the female metallic. No sex-based colour difference was recorded among the clearwing moth species examined, although Synanthedon culiciformis combined black-red with metallic coloration and S. cephiformis combined black-yellow with metallic coloration. Some mimics also reproduced behaviour as well as appearance: certain clearwing moths imitate the flight and buzzing of their models, while Plagionotus arcuatus resembles a wasp most strongly when moving.

The survey identifies a regional pattern of widely shared warning signals, but it does not directly measure predator responses, attack rates or survival benefits. Its authors interpret the abundance of aposematism among bees and wasps as compatible with protective mutual resemblance, while clearwing moths and other similarly coloured insects may gain protection through Batesian mimicry of defended models. They also note that coloration can serve purposes beyond defence, including thermoregulation, and that chemical communication may mediate some interactions between parasitic insects and their hosts. The analysis is geographically limited to the Czech fauna, relies on visual records from collections and photographs, and condenses varied patterns into four broad categories. Within those limits, it shows that nearly three-quarters of the bee and wasp species examined carried aposematic patterns and that clearwing moths, hoverflies and longhorn beetles displayed many of the same combinations.

Subject of Research: Comparative survey of aposematic colour patterns in Czech bees, wasps and their principal mimic groups

Article Title: Proportions of aposematic colouration in bees and wasps ( Hymenoptera , Aculeata ) and their main mimics – hoverflies, clearwing moths and longhorn beetles

Article References: Bogusch, P., & Zahradníková, A. (2025). Proportions of aposematic colouration in bees and wasps (Hymenoptera, Aculeata) and their main mimics – hoverflies, clearwing moths and longhorn beetles. Journal of Hymenoptera Research, 98, 325-338. https://doi.org/10.3897/jhr.98.141208

Image Credits: AI Generated

DOI: 10.3897/jhr.98.141208

Keywords: aposematism, warning colouration, bees, wasps, hoverflies, clearwing moths, longhorn beetles, mimicry, Czech Republic, insect colouration, Proportions, aposematic

Euphydryas maturna, the scarce fritillary, is a Eurosiberian woodland butterfly distributed from eastern France across Central Europe and southern Scandinavia to the Urals and beyond, toward the Baikal region. It depends on open-canopy broadleaf woodlands with species-rich herb layers, habitats that once thrived under historical forestry practices such as forest pasture and coppicing. When those practices were abandoned across much of Europe during the twentieth century, the woodlands darkened and the butterfly retreated. In the Czech Republic the decline was especially severe: the species was historically recorded from 29 mapping squares out of 675, but today survives at a single locality. By the late twentieth century it was even considered nationally extinct, until the naturalist Vrabec discovered a hitherto unknown population roughly 12 kilometres from a historically known, then already unoccupied site.

That discovery set the stage for one of the longest continuous monitoring efforts devoted to a single butterfly population in the region. Since 2001, experienced surveyors equipped with binoculars have systematically combed the Dománovice forest reserve each summer, counting the communal silken larval nests that the species builds on ash saplings and low-hanging branches between mid-July and mid-August. Every nest detected is GPS-recorded, and the resulting maps are handed to woodland managers to guide their work. The full survey takes six to ten person-days per season. In four years, mark-recapture studies added estimates of adult numbers, allowing researchers to relate flying butterflies to the nests they produce.

The 20-year time series tells a dramatic story. Two population peaks occurred, reaching 164 larval nests in 2006 and 202 in 2017. Each peak was preceded by a multi-season plateau with more than 100 nests, and each was followed by a season with diminished but still high numbers, then by a bust in which nest counts fell to roughly eight percent of the peak values. The lowest counts ever recorded were just 11 nests in 2010 and 7 in 2020. The gap between the arithmetic mean of 92.6 nests per year and the harmonic mean of 36.3 reveals just how skewed the distribution is toward the bust years. The mark-recapture data showed that about four adults are needed to produce each larval nest, a ratio that varied little with the stage of the cycle.

What makes the pattern scientifically valuable is the population’s complete isolation. Immigration into the Dománovice forest is practically impossible, so the observed dynamics cannot be explained by individuals moving among local populations with independent local dynamics, a factor that often obscures cyclic patterns elsewhere. The 11-year period is long, but it falls within the range known for cyclically fluctuating woodland moths, which spans from three to eight years in species such as the gypsy moth to 12 to 20 years in some budworms. Similar fluctuations have been documented in scarce fritillary populations in Salzburg in Austria, in Steigerwald in Germany, and in Hungary, with the Austrian data showing amplitude and period remarkably similar to the Czech population.

The authors attribute the cycling to pressures of natural enemies, the classic suspect behind abundance cycles in woodland defoliating insects. The butterfly’s communal egg batches and gregarious young larvae attract large numbers of predators and parasitoids, and microbial or fungal infections are also possible. Until recently, the species’ rarity and legal protection precluded experimental quantification of infestation levels. An indirect line of support comes from the spatial distribution of the nests. During peaks, the nests spread evenly across the inhabited forest, concentrating at suitable open-canopy patches, whereas during busts most nests occupy marginal, peripheral positions. Contagion-like threats such as natural enemies or diseases tend to affect populations from their centroids toward the peripheries, sparing the edges, and it may also be harder for searching enemies to locate peripherally situated hosts. A trade-off may thus exist for the butterfly between developing in half-shaded mature forest, which is microclimatically suboptimal but less exposed to enemies, and developing at microclimatically suitable but infestation-exposed clearings.

Notably, the trajectory of increase, boom and bust followed an identical shape before and after 2011, when active management for the species began. Favourable management probably heightened and prolonged the boom phase, contributing to the longer plateau above 100 nests and the higher amplitude of the second peak, but it did not alter the overall pattern. The second cycle nonetheless ended with a steeper decline, a 90 percent reduction from 2018 to 2019, and the authors suggest that unfavourable weather deepened this bust. The year 2018 was historically the hottest ever recorded, and in ex-situ breeding a third of the larvae produced by unusually early-eclosing 2018 adults pupated and generated a partial second generation of 25 adults in September. In natural conditions such late-season adults would perish from scarcity of nectar and larval diet in the advancing autumn. The mild 2018 winter was followed by an Arctic spell in May 2019 that killed half of the pupae during a dozen nights with freezing temperatures, suggesting a lack of pupal cold hardiness in this species.

The cycling pattern also resolves contradictions in earlier reports based on shorter time frames. Alarm calls prompted by the low counts of 2002 and again in 2009 appeared unnecessarily alarmist shortly thereafter, when numbers recovered, but those warnings accelerated the adoption of more favourable site management and propelled the establishment of ex-situ rearing in 2017. Understanding that single-site conservation is doomed in the long term for strongly fluctuating insects, conservationists have already used captive-bred progeny to re-establish a population at the Libice forest, 11 kilometres away, releasing thousands of larvae between 2018 and 2020; searches there yielded 24 egg batches in 2019 and 16 larval nests in 2020. A further transfer is planned for the Žiželice forest, just 800 metres from the Dománovice forest, where open canopy structure is being restored.

The strategy follows metapopulation theory, which predicts that colonies connected by transfers of individuals should achieve mutually asynchronous abundance dynamics, stabilising the entire system against regional extinction. If all goes well, the remnant deciduous woodlands of the Elbe river alluvium will be re-settled by the scarce fritillary, with individual woods rather than clearings within them functioning as local colonies. A looming threat is ash dieback, caused by the fungus Hymenoscyphus fraxineus, which is already visibly declining ashes at all the Czech sites; planting ash saplings and increasing the abundance of the alternative host plant Lonicera nigra are considered possible rescue measures. For now, the 20-year record from Dománovice forest stands as a vivid demonstration that nature’s rhythms can defeat even the most dedicated single-site rescue, and that saving a cycling species means thinking in terms of woods, not clearings.

Subject of Research: Cyclic abundance fluctuations in a completely isolated population of the endangered butterfly Euphydryas maturna

Article Title: Cyclic abundance fluctuations in a completely isolated population of Euphydryas maturna

Article References: John, V., Pavlíčko, A., Vrabec, V., Rybová, V., Andres, M., & Konvicka, M. (2021). Cyclic abundance fluctuations in a completely isolated population of Euphydryas maturna. Nota Lepidopterologica, 44, 213-222. https://doi.org/10.3897/nl.44.69153

Image Credits: AI Generated

DOI: 10.3897/nl.44.69153

Keywords: Euphydryas maturna, checkerspot butterflies, population cycles, natural enemies, metapopulation, butterfly conservation, Czech Republic, larval nest monitoring, habitat management, ex-situ breeding, ash dieback, Cyclic

The hornet’s story in Europe began quietly in 2004, when a queen, possibly just a single individual, was accidentally transported from China to France. Genetic analyses suggest this tiny founding population was enough to seed an invasion. By 2017, Vespa velutina had colonized nearly all of France, and from there it spread with remarkable speed: Spain in 2010, Portugal in 2011, Italy in 2013, Germany in 2014, and the United Kingdom in 2016. By 2020, individuals were turning up in Switzerland, the Netherlands, and Ireland. More recently, nests were discovered in 2023 in the Czech Republic and Hungary, and in Slovakia in 2024, while a lone individual was recorded in Austria. The invasion has now jumped continents, with the first colonies found near Savannah, Georgia, in the United States in 2023, and queens reported in New Zealand in November 2025.

The ecological and economic stakes are high. Vespa velutina hunts honeybees, locates apiaries, and decimates colonies, threatening local beekeeping operations and the livelihoods tied to them. It also preys on pollinators and decomposers more broadly, feeds on fruit, and reduces the abundance of insects that underpin ecosystem functioning. Because rising temperatures across Europe are expected to accelerate its spread, researchers emphasize that continuous efforts to stop or slow the invasion are urgently needed. Management typically operates on three levels: prevention, early detection, and eradication. Successful eradications have been achieved in the United Kingdom and on the Spanish island of Mallorca, but these victories depended on rapid detection and the elimination of every nest before the population could gain a foothold.

This is where public engagement becomes critical, and where current approaches fall short. Citizen reporting dramatically expands the area under surveillance, but the general public turns out to be surprisingly poor at identifying the hornet. In Guernsey, only 16.8 percent of public reports over three years were correct identifications. Other studies estimated public accuracy at roughly 30 percent, and among visitors at a bee festival, a motivated and experienced audience, only 33 percent identified the species correctly. In Mallorca, despite a successful eradication, a specially developed reporting app was downloaded by fewer than 3,700 people, less than half a percent of the island’s population. The researchers behind the new study identified two main bottlenecks: only a small fraction of the public is even aware of the threat, and those who do report often misidentify the species, complicating nest searches and wasting expert resources.

To test whether education could overcome these barriers, the team developed a targeted program for pupils aged 10 to 11 in České Budějovice, a South Bohemian city that the hornet has not yet reached but where its arrival is considered highly probable. Twenty classes took part between October and December 2024. The curriculum covered the hornet’s biology, its ecological and economic impacts, and its key identification features, with a strong emphasis on practical demonstration. Crucially, instead of photographs, the children examined real specimens embedded in transparent resin, including Vespa velutina workers and commonly confused native species such as the common wasp, the German wasp, and the European hornet. Handling resin-embedded insects avoided the fear or disgust that direct contact with stinging insects might provoke, while physical specimens helped prevent the misidentification errors that images alone can cause. A leaflet with a reporting telephone number was displayed in classrooms, and pupils without phones were encouraged to report sightings through their teachers.

The educational impact was measured rigorously. Pupils completed a short pre-test immediately before the program, the same test one week afterward, and a follow-up test two to three months later. Statistical analysis using repeated-measures ANOVA revealed a highly significant improvement in both knowledge scores and identification accuracy, with p-values below 0.001 in each case. Importantly, the gains were retained months later, indicating that the information had entered long-term memory. Before the program, awareness of the hornet was almost entirely limited to children already involved in beekeeping through their families. Afterward, the majority could correctly recognize the invasive species and distinguish it from its harmless native look-alikes.

The most striking test came six months after the program, in June 2025, when the researchers placed a dead Vespa velutina specimen on the classroom windowsill in participating schools. Fourteen of the twenty teachers consented to this covert experiment, and school staff were instructed not to alert pupils or remove the specimen during cleaning. The dead hornet sat in plain view for up to five consecutive days. In nine of the fourteen classes, or 64.3 percent, its presence was reported. Five classes reported it on the very first day, and four more the following day. In one memorable case, a pupil noticed the specimen on day one, took it home for careful examination overnight, and reported it to the teacher the next morning after confirming the identification. The scenario deliberately mimicked real-world conditions: the first recorded observation of the hornet in Austria in 2024 was a dead individual found on a hospital windowsill, and a hornet trapped indoors over a weekend would plausibly end up in exactly the same way.

Just as important as the successful detections was what did not happen next. Three months later, in September 2025, the researchers repeated the experiment with a dead European hornet, Vespa crabro, a large native vespid frequently mistaken for the invader. Not a single false report of Vespa velutina came in, either from the trained classes or from five additional classes that had not taken part in the earlier phase. The children had not merely learned to flag anything big and striped; they had learned the diagnostic features well enough to hold their fire when the wrong species appeared. This precision addresses one of the most persistent weaknesses of citizen science programs, in which floods of inaccurate reports raise verification costs and erode the value of public data.

The authors acknowledge limitations. The practical assessment ran in only fourteen classrooms, which constrained the original design of simultaneously testing the invasive and native species in different rooms. Because the control phase took place after the summer holidays, class compositions had shifted slightly, with most pupils retained but some turnover in a few classes. The study also tested recognition of dead specimens rather than flying hornets or individuals feeding on fruit, a constraint imposed by safety considerations and the need for a realistic simulation. Still, the researchers argue that June and September are comparable testing windows, since children are distracted at the end of the school year just as they are readjusting at the start of a new one, and attention to the hornet had already waned by the time of the June test.

The broader implications reach well beyond one Czech city. School-based programs are cheap, easy to implement, and can rapidly create hundreds of informed observers who understand the threat and know how to report it. Even if only a fraction of trained children remain vigilant over time, the sheer numbers involved mean that reliable reports could increase substantially, easing the shortage of citizen scientists and reducing the expert verification burden that drives up eradication costs. Involving children in a genuine, consequential task also boosts motivation and awareness, benefits that extend beyond biosecurity. The researchers recommend repeating such programs yearly, potentially woven into science curricula on invasive species, and deploying them urgently in Central European countries at the invasion front, such as Austria, Slovakia, and Hungary, as well as in the United States, New Zealand, and Mexico, where the hornet has arrived or is expected. In regions where the related and even more dangerous Asian giant hornet, Vespa mandarinia, is beginning to spread, educational content could cover both species. As warming climates push invasive hornets into new territory, the study suggests that the frontline of early detection may run straight through the classroom, where a modest investment in education can yield a distributed, accurate, and motivated detection network at almost no cost.

Subject of Research: School-based education programs for early detection of the invasive yellow-legged hornet Vespa velutina

Article Title: Children as frontline detectors: School-based programs can enhance early monitoring of Vespa velutina

Article References: Ditrich, T., & Lustová, Š. (2025). Children as frontline detectors: School-based programs can enhance early monitoring of Vespa velutina. NeoBiota, 104, 381-392. https://doi.org/10.3897/neobiota.104.174530

Image Credits: AI Generated

DOI: 10.3897/neobiota.104.174530

Keywords: Vespa velutina, yellow-legged hornet, invasive species, citizen science, early detection, school education, biological invasions, apiculture, pollinators, Czech Republic, species identification, eradication

The study, published in the journal Acta Ichthyologica et Piscatoria, draws on records from five fishing grounds spanning four rivers in the Czech Republic between 2007 and 2020. Researchers from local angling associations compiled stocking dates, fish numbers and weights alongside mandatory entries in anglers’ yearly fishing permits, then analyzed how quickly stocked rainbow trout, Oncorhynchus mykiss, were caught and whether returns differed between two distinct types of water management. The comparison pitted non-trout fishing grounds, where anglers may use natural baits with few restrictions, against designated trout grounds, where only artificial flies and lures are permitted and the season is limited to mid-April through the end of November.

The rainbow trout is not native to Europe. Introduced to the Czech Republic at the end of the nineteenth century, the species now supports a substantial aquaculture industry that produced 438 tonnes in 2022, of which 81 tonnes were taken by anglers in open waters. Because natural reproduction in Czech rivers is highly unlikely, every rainbow trout an angler catches was almost certainly stocked. Between 2017 and 2022, the mean annual catch reported by the two major angling unions reached 167,563 fish weighing 73,488 kilograms, making the rainbow trout the third most commonly caught species in the country after common carp and common bream.

The centerpiece of the analysis was the Svitava River, a non-trout fishing ground that flows directly through the city of Brno and its 400,000 residents. There, the pattern was dramatic. Across three sampled years, between 72.8 and 96.6 percent of all rainbow trout caught on local permits were landed within the first two weeks after a stocking event. Catch numbers spiked immediately after each release and fell essentially to zero in the days just before the next batch of fish arrived, indicating that fish from earlier stockings contributed almost nothing to later catches. By contrast, the four designated trout grounds showed a significantly lower two-week share, averaging 64.1 percent compared with 92.3 percent on the non-trout ground, a difference the authors confirmed as highly significant using generalized linear mixed models.

The researchers attribute this contrast to the rules of the game. On trout grounds, anglers are limited to three one-day trips per week and must fish with barbless artificial flies and lures, and only holders of a trout permit may fish at all. On the non-trout ground, no weekly trip limit exists, baited hooks are allowed, and fishing is legal year-round. The result is intense, bait-driven fishing pressure concentrated in the fortnight after each release on the Svitava, while trout grounds spread catches more evenly across the season, with roughly 30 to 50 percent of fish typically taken later than two weeks after stocking.

Return rates over the full year, however, turned out to be remarkably similar between the two management regimes. Individual return rates ranged from 36.8 to 53.4 percent on the non-trout ground and from 29.8 to 68.4 percent on trout grounds, while weight-based returns spanned 47.7 to 79.5 percent and 34.4 to 75.3 percent respectively, with no statistically significant differences in either measure. In other words, regardless of how the river was regulated, only about half of the stocked rainbow trout were ever caught and harvested, leaving the fate of the other half largely unknown.

That missing half is a familiar puzzle in put-and-take fisheries. Studies from North America suggest hatchery rainbow trout disperse rapidly from stocking sites, with nearly all fish either dying quickly or emigrating through long-range movements. The Czech authors point to additional pressures including transport stress, predation by fish-eating birds, illegal fishing and unregistered removals. Somewhat surprisingly, the density of human population around each fishing ground did not predict return rates. The Brno city stretch and sparsely populated headwaters delivered comparable returns, and neither the number of stocking events nor the number of release sites appeared to matter, suggesting weather, hydrology and the timing of releases relative to weekends and holidays are the real drivers of fishing success.

The data also revealed an amusing quirk of self-reported catch records. On average, anglers reported fish heavier than those stocked, most dramatically in 2019 on the Svitava, where fish averaging 314 grams at release were reported at 468 grams when caught. Given that most fish were caught within days of stocking, the authors suggest anglers may consult an indicative weight table in their regulation booklets or simply overestimate their catch, a phenomenon they describe as subjectively distorted reporting. Slightly longer residence times on trout grounds, where fish can genuinely feed and grow after release, may account for part of the pattern, since stocked trout do begin taking natural drift and benthic prey almost immediately even if their post-hatchery diets differ from those of wild salmonids.

The findings carry practical weight well beyond the Czech Republic. Put-and-take stocking is a widespread tool for sustaining recreational fisheries on non-native salmonids, and the Czech return rates of roughly 30 to 60 percent compare favorably with figures from North American and Australian waters, which often hover near 23 to 27 percent, likely because those lakes and rivers are far larger and the fish harder to catch. The results also touch on animal welfare, since catch-and-release mortality is known to be far higher with baited barbed hooks, common on non-trout grounds, than with the barbless artificial flies and lures mandated on trout grounds. For managers, the message is clear: in put-and-take systems, most stocked trout are essentially a short-term delivery of harvestable fish, and the timing of releases matters as much as the number of fish in the tank.

Subject of Research: Stocking efficiency and catch timing of rainbow trout in Czech recreational fisheries

Article Title: Annual catch of rainbow trout, Oncorhynchus mykiss ( Actinopterygii , Salmoniformes , Salmonidae ), in fishing grounds in the Czech Republic, related to stocking

Article References: Adámek, Z., Šlapanský, L., & Jurajda, P. (2025). Annual catch of rainbow trout, Oncorhynchus mykiss (Actinopterygii, Salmoniformes, Salmonidae), in fishing grounds in the Czech Republic, related to stocking. Acta Ichthyologica et Piscatoria, 55, 151-160. https://doi.org/10.3897/aiep.55.148612

Image Credits: AI Generated

DOI: 10.3897/aiep.55.148612

Keywords: rainbow trout, Oncorhynchus mykiss, stocking, recreational fishing, put-and-take fisheries, Czech Republic, return rates, trout fishing grounds, fisheries management, anglers' catches, non-indigenous species, Annual

The research team, working with material housed in the palaeontological collections of the National Museum in Prague, abandoned the traditional route of hunting for discrete anatomical characters, because there simply are none to find. The fossils preserve only the general vaulted outline of the cephalon, a raised longitudinal region, and a vague indication of the eyes; a single Zonozoe specimen shows what may be glabellar furrows, and Zonoscutum preserves similar structures in a different position. Crucially, all of the diagnostic features of the groups these fossils have been linked to, including the aglaspidids and their relatives within the clade Vicissicaudata, are post-cephalic, meaning they lie in body regions that were never preserved. Standard phylogenetic analysis, which depends on a matrix of observable traits, has therefore been effectively impossible. Earlier workers, including a major 2013 analysis of Vicissicaudata and a 2022 revision of the material, had concluded that the most anyone could honestly say was that the fossils belonged somewhere within the broad clade Artiopoda, the great assembly of extinct arthropods that includes trilobites and their kin.

The new study took a different path: instead of asking what features the fossils have, it asked what shape they are. The researchers compiled cephalic outlines from thirty-three early Palaeozoic arthropod species, spanning nine euchelicerates, six aglaspidids, three cheloniellids, two nektaspids, and a selection of other artiopodans, alongside Zonozoe and Zonoscutum themselves. Trilobites were deliberately excluded, a decision grounded in three practical reasons: Ordovician trilobite cephalic morphology is so extraordinarily diverse that it would have swamped the signal with noise, Zonozoe and Zonoscutum have never seriously been considered trilobite relatives, and the position of the eyes and glabella in the two enigmatic genera differs markedly from any contemporaneous trilobite. Each outline was traced as a black silhouette and converted into a mathematical description using elliptical Fourier analysis, a technique that decomposes a closed shape into a series of harmonic coefficients, capturing its geometry in a form that computers can compare objectively.

The mathematics behind the approach is elegant in its simplicity. Fifteen harmonics were retained, sufficient to capture 99.9 percent of the harmonic power in the dataset, meaning that nearly all of the meaningful shape information was preserved in the analysis. These coefficients were then fed into two complementary statistical frameworks. A principal component analysis compressed the high-dimensional shape data into a visual morphospace, where similar shapes cluster together and dissimilar ones drift apart. A linear discriminant analysis, trained on the known group memberships, tested how well the major groupings, euchelicerates, non-vicissicaudatan artiopodans, and vicissicaudatans, could be told apart on outline shape alone. The first two principal components alone explained 87.1 percent of the variation in the dataset, with PC1 accounting for 67.4 percent and PC2 for 19.7 percent, an unusually clean separation for fossil material this fragmentary.

The results were striking. In the principal component space, Zonozoe plotted squarely within the vicissicaudatan morphospace, nestled between the cheloniellid Neostrabops martini and the aglaspidid Aglaspis barrandei. Zonoscutum landed nearby, close to the cheloniellids Triopus and Drabovaspis complexa and the artiopodan Naraoia, in the lower region of the vicissicaudatan area. Both taxa fell far from the euchelicerate cluster, which occupied its own distinct corner of the morphospace. The discriminant analysis reinforced the pattern: euchelicerates were cleanly separated from all other groups, achieving 77.8 percent classification accuracy in leave-one-out cross-validation, while Zonozoe and Zonoscutum plotted at the edge of the artiopodan space, decisively outside the euchelicerate region. In plain terms, the shapes of these mysterious head shields look like vicissicaudatan artiopodans, and they emphatically do not look like the horseshoe crab relatives that some nineteenth-century workers once imagined.

This matters because the two genera have been dragged through nearly every possible interpretation since Barrande first described Zonozoe as a large ostracod carapace. Novák, in an unpublished 1887 manuscript, considered it a merostomate close to the synziphosurines. Chlupáč assigned it to Aglaspidida in 1963, an assignment he himself flagged as uncertain, and the same tentative label was later applied to Zonoscutum. Part of the confusion stemmed from the aglaspidids’ own turbulent taxonomic history: during the twentieth century they were shuffled between Xiphosura, Merostomata, and positions as sister group to the chelicerates, before modern phylogenies anchored them firmly within Vicissicaudata, a branch of Artiopoda. For much of that period, Aglaspidida functioned as something of a wastebasket taxon, a destination for any Ordovician arthropod too incomplete to place elsewhere, and Zonozoe and Zonoscutum, with their aglaspid-like head shields and their occurrence in the same palaeogeographic region as known aglaspidids, were natural candidates for that fate.

The authors are careful about the limits of their method, and that caution is itself instructive. Both Zonozoe and Zonoscutum plotted closer to cheloniellids than to aglaspidids in the two-dimensional outline space, but the team argues this is likely an artefact of compression: Zonoscutum has a highly vaulted cephalon and cheloniellids extremely flattened ones, and flattening three-dimensional shapes into two-dimensional outlines distorts exactly such extremes. Three-dimensional volume data would address the problem, but such data are difficult to obtain for fossils scattered across collections on multiple continents, and are themselves affected by flattening during fossilisation. The researchers therefore decline to overturn the 2022 conclusion that rejected a close relationship with the coeval and sympatric cheloniellid Triopus. What the analysis does firmly support is the negative result: an euchelicerate affinity is effectively excluded, and the most conservative classification of both genera within Artiopoda gains quantitative backing, with a more specific affinity to Vicissicaudata now considerably strengthened.

There is even a bonus finding buried in the morphospace. The proximity of Zonozoe to Neostrabops martini, a Late Cambrian form whose own classification has long rested on limited evidence, prompted the authors to suggest that Neostrabops itself may deserve re-examination, potentially toward Aglaspidida or, more parsimoniously, toward Xenopoda. Meanwhile, the close placement of Zonozoe beside Aglaspis barrandei is consistent with older qualitative observations, such as the position of the eyes and glabellar furrows behind them, traits that are not strongly diagnostic on their own but now align with an independent line of quantitative evidence. Neither conclusion is presented as definitive, but together they show how a method designed to squeeze information from unpromising material can generate genuinely new hypotheses about specimens that formal phylogenetics cannot touch.

The broader significance of the study extends well beyond two obscure Czech fossils. Mould-preserved specimens, which rarely retain fine anatomical detail, are routinely excluded from evolutionary and palaeoecological analyses precisely because the discrete characters needed for phylogenetic matrices are absent. Outline-based morphometrics offers a reproducible, quantitative alternative: less precise than a full phylogenetic analysis, but capable of admitting specimens that would otherwise sit forever in the too-difficult drawer. In this case, the technique has provided evidence for the presence of non-cheloniellid vicissicaudatans in the Letná Formation based on material that traditional qualitative methods would have overlooked entirely. A 150-year-old puzzle has not been solved with a new specimen or a spectacular discovery, but with a ruler’s worth of geometry applied to the outlines of what little remains, and that may prove to be the study’s most enduring legacy: a demonstration that even the most fragmentary fossils in the world’s museum drawers still have stories their shapes can tell.

Subject of Research: Morphometric reclassification of the enigmatic Ordovician arthropod fossils Zonozoe drabowiensis and Zonoscutum solum from the Czech Republic

Article Title: A morphometric approach to the taxonomic dilemma of Zonozoe drabowiensis Barrande, 1872 and Zonoscutum solum Chlupáč, 1999 (Upper Ordovician, Czech Republic)

Article References: Lustri, L., Laibl, L., Collantes, L., Bruthansová, J., Nohejlová, M., Liu, Y., & Pates, S. (2026). A morphometric approach to the taxonomic dilemma of Zonozoe drabowiensis Barrande, 1872 and Zonoscutum solum Chlupáč, 1999 (Upper Ordovician, Czech Republic). Swiss Journal of Palaeontology, 145, 145-155. https://doi.org/10.3897/sjp.145.179154

Image Credits: AI Generated

DOI: 10.3897/sjp.145.179154

Keywords: palaeontology, Zonozoe drabowiensis, Zonoscutum solum, Ordovician, arthropods, morphometrics, elliptical Fourier analysis, Vicissicaudata, Artiopoda, Aglaspidida, Czech Republic, taxonomy

The encounter took place on 19 July 2016 at approximately 13:25 CEST near the village of Hynčice in the Protected Landscape Area of Broumovsko, in the Czech Republic, at an elevation of roughly 400 metres beside the river Stěnava. One of the authors of the study took random photographs of butterflies throughout the survey as part of routine documentation. Only during later analysis of the photo archive did the team notice that what had initially appeared to be an interesting shot of two species sharing a single inflorescence was in fact something far more unusual: the abdomen tips of a female P. nausithous and a male P. teleius were visibly connected, indicating an attempt to copulate. The researchers do not know how long the pair remained in copula, because the connection was discovered only in the photographs.

Both species belong to the genus Phengaris, a group whose members are famous for a parasitic relationship with Myrmica ants. The caterpillars of these large blues are carried into ant nests, where they are fed or feed on ant brood, a life history so complex that it has made the genus a model system for evolutionary ecology. Despite this intensive research attention, and despite the fact that P. teleius and P. nausithous frequently occur side by side at the same sites and share the same food plant across Europe, no previous record of interspecific mating or hybridization between members of this genus has ever been documented. The new observation therefore fills a surprising gap in the knowledge of one of the best-studied butterfly lineages in Europe.

The sighting was made during a systematic survey conducted from 4 July to 5 August 2016 across 13 habitat patches near the villages of Hynčice, Ruprechtice and Vižňov, all of them containing flowering great burnet, the exclusive larval food plant of both species in Europe. The survey was carried out as part of conservation monitoring obligations, since both butterflies are listed for protection under the EU Habitats Directive. The researchers used the Mark-Release-Recapture method, analysed with the program MARK 8.1 and modified according to established procedures for Phengaris, to estimate the density of the butterflies. The colonies in the area form a single metapopulation, with individuals dispersing between patches.

The population estimates reveal that the mating attempt occurred in a community where both species were well represented. Using the Cormack-Jolly-Seber method, the team calculated that the metapopulation contained approximately 802 individuals of P. teleius and 1487 individuals of P. nausithous. These figures matter for interpreting the event: the researchers considered whether unusually high densities might have caused confusion between the species, but concluded that the density at the observation site was neither higher than average nor so low that finding a conspecific partner would have been difficult. The abundance of both species at the site was, in other words, entirely ordinary, which makes the unusual behaviour harder to explain.

Interspecific mating is a rare phenomenon in butterflies generally, and it is far more commonly documented in some families than in others. Records from the wild are relatively rich for swallowtails in the genera Ornithoptera, Papilio and Troides, for whites of the genus Colias, and for nymphalids including Danaus, Erebia, Heliconius and Limenitis. The family Lycaenidae, to which Phengaris belongs, has produced only a handful of such observations. Previous lycaenid examples include matings between species of Callophrys and between species of Lycaena, as well as reports from India of copulation between Castalius rosimon and Talicada nyseus and between Chilades parrhasius and Zizina otis. For the genus Phengaris itself, the authors of the new study found no comparable record anywhere in the literature.

The vast majority of documented interspecific copulations in butterflies occur between species of the same genus, as in Limenitis, Colias, Danaus, Heliconius and the classic examples in Papilio. Rarer still are matings between different genera, and exceptional are cases spanning entire families, such as an observed union between the burnet moth Zygaena filipendulae and the tiger moth relative Amata phegea, or even between a nymphalid butterfly, Melitaea athalia, and that same moth species. Interspecific mating is a prerequisite for hybridization, yet natural hybridization in Lepidoptera remains rare. One celebrated natural hybrid is Erebia serotina, produced by males of E. pronoe and females of E. epiphron. Most known hybrids, by contrast, have been created in captivity, particularly among Papilio species, where hybrids can remain fertile for several generations.

Why would two species that normally maintain separate identities attempt to mate at all? Reproductive barriers in butterflies typically operate on several levels, combining olfactory recognition with species-specific behaviour, pheromones and other signals. However, mating pheromones often share similar chemical compositions across related species, and their content varies not only between species but also within single species. The lock-and-key mechanism of butterfly genitalia, long assumed to prevent mechanical mating between different species, does not always function reliably. Molecular studies have repeatedly shown that reproductive barriers in Lepidoptera usually hold firm, but when they fail, the willingness to mate is often strongly asymmetric between the species involved, as demonstrated by observations of male Papilio canadensis showing strong preferences for females of Papilio glaucus.

The authors of the new report propose possible explanations for the Bohemian encounter. Because species of Phengaris differ in the number of androconia, the scent-producing scales on their wings, one possibility is that individuals became confused when pheromones of both species mixed in the air, particularly if many butterflies were concentrated at the spot. Alternatively, a suitable partner of the same species might have been harder to detect if the pheromones of the two species are chemically similar. Yet the researchers note that neither explanation seems particularly convincing, given that population densities at the site were unremarkable. The true cause of the behaviour therefore remains unresolved.

The consequences of such events can range from negligible to profound. Hybridization can threaten vulnerable species when a related species colonizes or is introduced into a landscape, but it can also trigger the emergence of new species, as documented in Heliconius butterflies. In the case of the Bohemian observation, the photographic evidence confirms that the butterflies achieved a physical connection, but it remains far from certain whether the copulation was successful or whether deeper isolation mechanisms prevented any possibility of hybrid offspring. What the images do establish is that even in a genus whose ecology has been scrutinized more intensively than almost any other butterfly group, the boundaries between species can still, on rare summer afternoons, briefly dissolve.

Subject of Research: First photographic record of an attempted interspecies mating between the butterflies Phengaris nausithous and Phengaris teleius in the Czech Republic

Article Title: An attempt of interspecies mating between Phengaris nausithous and P. teleius ( Lepidoptera , Lycaenidae )

Article References: Pilařová, A., Zachardová, S., Fric, Z. F., & Vrabec, V. (2024). An attempt of interspecies mating between Phengaris nausithous and P. teleius (Lepidoptera, Lycaenidae). Nota Lepidopterologica, 47, 105-111. https://doi.org/10.3897/nl.47.118947

Image Credits: AI Generated

DOI: 10.3897/nl.47.118947

Keywords: Phengaris, Phengaris nausithous, Phengaris teleius, Lycaenidae, interspecies mating, butterflies, hybridization, reproductive barriers, Czech Republic, Sanguisorba officinalis, lepidoptera, conservation

The work, published in the journal MycoKeys, combines classical herbarium detective work with modern DNA sequencing. The newly described species, Myriospora hilitzeri, is named after Alfred C. Hilitzer, a Czech lichenologist who collected extensively in the 1920s and who also happened to write science fiction. In 1933 Hilitzer published a novel called Mitigen, gas against war, in which a scientist invents a gas that makes people no longer want to fight. Honoring a collector whose specimens still generate discoveries a hundred years later, the authors note, is a fitting tribute to a man who worked at the intersection of rigorous science and bold imagination.

Myriospora is a small but widespread genus of crustose lichens in the family Acarosporaceae. Until this study it contained thirteen accepted species found on every continent except Australia and Africa. The genus is defined by a set of microscopic traits: a tall spore-producing layer called the hymenium, usually exceeding 150 micrometers, extremely thin fertile filaments known as paraphyses measuring roughly one micrometer across, and an algal layer that is interrupted rather than continuous. Most species in the group produce few or no secondary metabolites, the chemical compounds lichenologists often rely on for identification, which makes morphology and DNA especially important for telling species apart.

To untangle the relationships within the genus, the team extracted DNA from seven dried herbarium specimens and sequenced four genetic markers: the nuclear internal transcribed spacer, the nuclear large subunit ribosomal DNA, the mitochondrial small subunit, and the protein-coding beta-tubulin gene. The concatenated alignment totaled 2,894 characters, of which 592 were parsimony-informative. Phylogenetic trees were built using both Bayesian inference and maximum likelihood, with the lichen Pycnora sorophora serving as the outgroup. The resulting well-supported phylogeny confirmed that Myriospora is a monophyletic clade, meaning all its species descend from a single common ancestor, and revealed that the sequences of the new species form a distinct lineage separate from all other members of the genus except its two closest relatives.

Myriospora hilitzeri itself is easy to overlook and has been misidentified repeatedly. It forms pale brown, smooth to lumpy areoles, small tile-like patches of the lichen body, typically around two millimeters wide, each bearing one to four immersed fruiting bodies called apothecia. Under the microscope it can be distinguished from its lookalike Myriospora myochroa by its flatter areoles, a much narrower parathecium, the rim of tissue surrounding the apothecium, a lower hymenium, and crucially the absence of norstictic acid, a compound that M. myochroa produces. The species grows on siliceous, acid rocks, sometimes in sheltered underhangs, at elevations ranging from 130 meters in the Czech lowlands to about 2,750 meters in the Maritime Alps of Italy.

The story of the second species is more dramatic. In August 1925, Hilitzer collected a lichen on the summit of Keprník Mountain at 1,424 meters in the Jeseníky Mountains. The Swedish lichenologist Adolf Hugo Magnusson studied the specimen and in 1929 described it as a form of Acarospora smaragdula, naming it Acarospora smaragdula form macrophylla. The lichen is unmistakable: its squamules, scale-like lobes of the thallus, reach four to ten millimeters wide and up to 1.35 millimeters thick, borne on stout stalks, with ten to twenty apothecia embedded in each one. Such large squamules overshadow and apparently destroy neighboring lichens, a competitive habit unusual in the genus. Hilitzer himself wrote that only a small number of low gneiss rocks existed at the Keprník summit, and it was there, and only there, that he found the species.

No one has collected it since. Hilitzer never found it again, and generations of Czech lichenologists, from early twentieth-century figures to contemporary researchers, have failed to rediscover it. In April 2019, a team revisited the Keprník summit and found only Myriospora hilitzeri tucked in a rock underhang, not the large, sun-exposed squamules of macrophylla. Because the species is conspicuous and could not easily be missed by any skilled lichenologist, and because repeated targeted searches have come up empty, the authors consider Myriospora macrophylla probably extinct in the Czech Republic. Because no material suitable for DNA extraction could be obtained, the species was not included in the molecular phylogeny; its recognition rests on its unique morphology, its historical description, thin-layer chromatography of a tiny fragment, and examination of the type specimens and photographs of the holotype held in Sweden.

The genetic work also produced a surprise from North America. A specimen of Myriospora smaragdula collected in Canada by Jesuit lichenologist John McCarthy on calcareous rock rich in iron fell squarely within the M. smaragdula lineage. That is remarkable because no Myriospora species had ever been reported on calcareous rock, and M. smaragdula was known to favor copper-rich substrates. A lichen curator at the Slovakia National Museum examined the specimen with Raman spectroscopy searching for novel mineral oxalates, but found only whewellite, calcium oxalate monohydrate, one of the most common oxalates in lichens, crystallized on the underside of the squamules where they touched the rock. The finding hints that the ecological tolerances of even well-known lichens may be broader than current records suggest.

The study also tidies up the genus’s boundaries. The authors reject Myriospora himalayensis, published in 2021 from the Himalayas, arguing that the traits used to justify its placement, a high hymenium, small ascospores, norstictic acid and pruinose apothecia, are not restricted to Myriospora, and that the single known specimen needs sequencing before it can be assigned to the genus. They likewise flag reports of the Californian species M. hassei from Europe and interior North America as doubtful, noting that some may represent undescribed taxa or even M. hilitzeri itself. With the two additions, the genus now contains fifteen accepted species, and the paper supplies a worldwide identification key to all of them, a practical tool for lichenologists everywhere.

Beyond the taxonomy, the study is a reminder of how much biodiversity history is stored in herbarium packets. Hilitzer’s collections from the 1920s, some with illegible labels and others annotated by Magnusson with identifications later shown to be wrong, turned out to hold a species new to science hiding in plain sight for a century. They also preserve the only trace of a distinctive lichen that may have vanished from its single mountaintop home. As genomic methods grow more powerful and old specimens are re-examined with modern tools, researchers expect more such revelations, and more sobering reckonings with what has been lost while it sat, unrecognized, on a museum shelf.

Subject of Research: Taxonomy and phylogenetics of two new European lichen species in the genus Myriospora

Article Title: Two new species of Myriospora ( Lecanoromycetes , Acarosporomycetidae , Acarosporales , Acarosporaceae ) from Europe, one last observed in 1925

Article References: Knudsen, K., Pušová, T., Kocourková, J., & Kondrysová, E. (2026). Two new species of Myriospora (Lecanoromycetes, Acarosporomycetidae, Acarosporales, Acarosporaceae) from Europe, one last observed in 1925. MycoKeys, 139, 73-87. https://doi.org/10.3897/mycokeys.139.200273

Image Credits: AI Generated

DOI: 10.3897/mycokeys.139.200273

Keywords: lichenology, Myriospora, Acarosporaceae, new species, phylogenetics, DNA sequencing, Czech Republic, biodiversity, possibly extinct, taxonomy, MycoKeys, Europe

The study, conducted in the Vysočina Region of the central Czech Republic, evaluated two types of combined deterrents that had never before been verified in published research. The first, Deer Deter DD430 Generation 5 from the Austrian manufacturer iPTE Traffic Solutions, is an optical-acoustic device activated by an internal daylight sensor from dusk until dawn. When a vehicle’s headlamps are detected at distances of 300 to 500 metres, the device flashes royal blue and amber LEDs while simultaneously emitting a high-frequency acoustic alert in the range of 3.5 to 6.5 kilohertz. The second, Hagopur Kombiset Multiwarn Wildlife Protector from Germany, combines an optical component of eight multi-coloured honeycomb platelets with an olfactory element: a semi-circular chamber containing a sponge soaked in odour concentrate, renewed every three months as the manufacturer recommends. The researchers hypothesised that combining two different stimuli in each device would prove more effective than single-stimulus approaches tested in earlier studies.

The experimental design was unusually rigorous for this field. The team selected seven road sections totalling 18.6 kilometres, all identified as animal-vehicle collision hotspots using the KDE+ method, which pinpoints road segments where collisions cluster at higher frequencies than the surrounding network. Four sections received the Deer Deter devices and three received the Hagopur Kombiset, with units installed every 50 metres along both sides of the road on triangular delineator posts. Crucially, the researchers also monitored seven control sections spanning 88 kilometres of adjacent road, 4.7 times longer than the test sections, to capture any landscape-wide trends in mortality that might otherwise be misattributed to the deterrents. Cadaver monitoring was carried out continuously at weekly intervals: 21 months before installation, from March 2022 to November 2023, and 18 months after, from December 2023 to May 2025.

Data collection drew on three independent sources, an above-standard methodological approach. The researchers themselves walked the test sections back and forth on both sides of the road, recording species, photographs, dates and GPS coordinates for every carcass of roe deer, fallow deer, wild boar, red fox, European brown hare and stone marten. Local hunting association managers from 11 hunting grounds contributed records, as Czech law places responsibility for documenting and removing road-killed game within their competence. Finally, the police database of wildlife collisions provided a third stream of data covering both test and control sections. The team acknowledged that police records capture only a subset of animal-vehicle accidents, but assumed underreporting was evenly distributed across the study area, excluding spatial bias. Traffic intensity was measured directly using mobile automatic counters employing Doppler-effect radar, deployed for at least 168 hours during May and November of 2023 and 2024, periods chosen to coincide with peak roe deer and wild boar migration and mortality.

The statistical analysis followed the Before-After-Control-Impact design widely recommended in road ecology literature. Mortality data were annualised and adjusted for section length, expressing wildlife deaths per kilometre per year, and effect sizes were calculated as standardised mean differences using Hedges’ d, adapted to a before-after comparison. Five analytical models were run, ranging from the researchers’ own data alone to combinations incorporating police and hunter records, including one conservative specification that excluded hunter data from treated sections to ensure structural comparability with control sections. Parametric paired t-tests, non-parametric sign tests, Mann-Whitney U tests, ANOVA and regression models were all applied, with the sign test chosen specifically because very small sample sizes rendered conventional non-parametric methods unreliable.

The results delivered an unexpected twist. Mean annual wildlife mortality per kilometre did decrease after deterrent installation across most sections and most models, but the reductions were statistically weak. Sections treated with the Hagopur Kombiset showed a mean mortality reduction of 22.0 percent, while Deer Deter sections averaged only 7.2 percent, neither reaching statistical significance, with confidence intervals so wide they spanned both meaningful reductions and negligible effects. The control sections, where no deterrents were installed at all, recorded a 45.5 percent decline in mortality, a statistically significant decrease. In other words, mortality fell more on untreated roads than on roads fitted with the devices, suggesting the observed declines reflected natural fluctuations operating at landscape scale rather than any effect of the deterrents themselves.

The Control-Impact comparisons confirmed this interpretation. None of the statistical tests, whether Mann-Whitney U, t-tests or ANOVA across all three groups, revealed significant differences between deterrent-equipped and control sections. Regression models estimating how device type influenced effect size produced coefficients for both the Deer Deter and Hagopur Kombiset variables that were statistically non-significant across all five models, with p-values far above standard thresholds. The researchers noted that the negative intercepts, significant in four of five models, indicated a general decline in mortality across the region during the study period, probably driven by unmonitored external influences such as natural population fluctuations, crop distribution along roads, road characteristics, weather conditions and disturbance, rather than by any sharp decline in local game populations, since hunting rates remained stable.

Traffic intensity emerged as a more meaningful correlate of mortality. In the researchers’ own monitoring data, traffic volume after installation showed a strong positive correlation with mortality, with Pearson’s r reaching 0.84 and Spearman’s rank correlation 0.71, both statistically significant. The percentage change in mortality was also significantly associated with traffic intensity in this dataset. This aligns with a 2020 review reporting that traffic had a predominantly positive effect on animal-vehicle collisions in 75 percent of examined studies, meaning collision risk rises with traffic volume. The researchers also documented practical shortcomings: roughly 20 percent of Deer Deter devices failed night functionality checks, largely because insufficient solar charging, caused by shading vegetation, roads in cuttings or improper panel orientation, drained their batteries, particularly during short winter days and on heavily trafficked roads.

Behavioural observations reinforced doubts about the devices’ underlying principle. Hunters reported seeing fallow deer and wild boars at night near sections equipped with Deer Deter devices, showing no signs of disturbance from the sound and light signals while cars passed by. The study’s authors point to stimulus habituation, a core principle in behavioural ecology, as a likely explanation for the broader failure of light and sound deterrents: animals rapidly learn to ignore predictable, non-threatening cues that lack consistent negative reinforcement. Devices emitting wavelengths or frequencies outside a target species’ perceptual range may be undetectable or meaningless altogether. The team emphasised that no ethological validation, testing whether animals respond to the deterrent stimuli at all, was ever conducted for these specific products, and argued such investigations should precede any field deployment.

The researchers conclude that the tested deterrents showed no statistically significant effect in reducing mortality of the selected wildlife groups, and that despite decades of use, strikingly few studies have evaluated their real effectiveness in field conditions. They call for an end to trusting testimonial reports from product manufacturers, urging rigorous applied ethological research, standard performance protocols and multi-site validation studies so that only measures with proven efficacy are deployed at scale. The findings apply exclusively to the tested device types from specific manufacturers within the particular landscape and traffic context of the Vysočina Region and cannot be generalised to other devices operating on the same principle. For wildlife conservation, human safety and public finances, the knowledge gap remains concerning, and the elusive solution to safer road crossings continues to demand evidence before hardware.

Subject of Research: Effectiveness of combined wildlife deterrent devices for reducing animal-vehicle collisions on roads

Article Title: On the road chasing the elusive solution: Evaluating combined deterrents for safer wildlife road crossings

Article References: Strnad, M., Křápek, M., Dostál, I., Uhlíková, J., Slepica, M., & Hlaváč, V. (2026). On the road chasing the elusive solution: Evaluating combined deterrents for safer wildlife road crossings. Nature Conservation, 63, 173-198. https://doi.org/10.3897/natureconservation.63.170760

Image Credits: AI Generated

DOI: 10.3897/natureconservation.63.170760

Keywords: wildlife road crossings, animal-vehicle collisions, road ecology, wildlife deterrents, optical-acoustic deterrents, olfactory repellents, BACI design, road mortality, habituatation, traffic intensity, Czech Republic, Nature Conservation

Nowhere is the problem more insidious than in the eyes of ordinary observers. Because the three species are so similar externally, anglers, pond owners, and citizen scientists who submit photo-based records may simply be guessing wrong. A new study published in Nature Conservation put that concern to a direct test, asking hundreds of visitors at a major Czech angling fair to identify photographs of the three species. The results reveal a striking pattern: identification success depended far more on which individual fish was shown than on who was doing the identifying, and the errors were not random but flowed in directions that could actively distort conservation data.

The experiment took place at the For Fishing 2023 fair in Prague, an enormous gathering that drew more than 27,000 anglers to over 18,000 square metres of exhibition space. As part of outreach for the Save the Crucian Carp campaign, researchers set up a forced-choice identification quiz. Each participant received a printed sheet with nine photographs, three per species, all taken under controlled lighting, background, distance, and angle. Crucially, the fish selected were not idealised textbook specimens but realistic individuals spanning the genuine phenotypic variation encountered in the field, including deliberately confusion-prone types such as small-bodied gibel carp and a dark, naturalised goldfish. Participants had to label every photograph with one of three species names; no do-not-know option was offered, and outside help was prohibited.

After quality control, responses from 325 participants yielded 2,925 identification trials. Overall accuracy across answered trials was a moderate 64.3 percent, a figure that might seem encouraging until it is unpacked. Descriptively, goldfish fared best at 77.6 percent, crucian carp came in at 63.1 percent, and gibel carp languished at 52.4 percent, barely better than a coin flip. But the statistical modelling told a subtler story. When the researchers fitted binomial generalised linear mixed models with random intercepts for both respondents and photographs, the species-level differences dissolved into statistical insignificance, while the photograph itself emerged as the dominant source of variation.

That image-level effect was enormous. Adding photograph identity as a random effect dramatically improved model fit, and within each species the three images differed significantly in how easily they were recognised. The gibel carp photographs were the most extreme case: two small-bodied individuals were correctly identified only about a third of the time, while a large, robust adult was identified 89.5 percent of the time. Model-based predicted probabilities of a correct answer ranged from 0.33 to 0.92 depending purely on which photograph was shown. In other words, the salience of diagnostic traits in a specific individual fish, not the species it belonged to, largely determined whether an observer got it right.

The direction of the mistakes is what should concern conservationists most. For the two small gibel carp images, the most frequent wrong answer was crucian carp, selected in over 51 percent of answered trials for each. Meanwhile, one crucian carp photograph was labelled as gibel carp in 39.3 percent of responses, and the naturalised, bronze-coloured goldfish drew substantial confusion, with 31.6 percent of respondents calling it a crucian carp. Only the bright orange ornamental goldfish images were essentially unambiguous, scoring above 88 percent. The pattern fits classic categorisation research on typicality effects: people recognise prototypical examples easily but stumble badly when a species presents a phenotype that overlaps visually with another.

Why does this matter for the fate of a critically endangered fish? Because photo-based citizen science records feed directly into monitoring, early detection of invasives, and management decisions. Directional confusions translate into systematic false positives and false negatives rather than noise that averages out. When small gibel carp are routinely reported as crucian carp, the apparent range of the endangered native species is inflated while the spread of the invader is masked. Worse, well-intentioned anglers or pond managers might move, stock, or protect fish they believe are crucian carp, inadvertently aiding gibel carp dispersal. The reverse error, labelling a genuine crucian carp as an invasive, can discourage protection or even trigger lethal management of the wrong fish. Recent participatory monitoring of crucian carp in Central Europe underscored the stakes: field verification confirmed the species in only 35 percent of submitted tips.

Experience helped, but only modestly. Model selection based on the corrected Akaike Information Criterion supported a parsimonious model in which angling-related expertise and education contributed to explaining accuracy, with anglers showing a small but statistically reliable improvement over other visitors, an odds ratio of 1.56. Age and sex received little support. The key insight is that even among fair attendees, a self-selected crowd with strong interest in fish, performance remained constrained by image ambiguity. Expertise and training can reduce misidentification, but they cannot compensate for diagnostic cues that are simply invisible or weakly expressed in a particular photograph, a limitation also documented in professional fisheries monitoring contexts.

The underlying biology compounds the problem. Crucian carp body depth varies with ecological conditions, gibel carp shows substantial phenotypic plasticity, and goldfish spans an enormous spectrum from ornamental orange to dark wild-type forms after decades of domestication and feralisation in European waters. Moreover, several of the formally diagnostic characters used by taxonomists, including gill-raker counts, lateral-line scale counts, peritoneum colour, and the serration of fin rays, simply cannot be assessed from a standard lateral photograph. Some individuals may therefore remain genuinely unassignable from images alone, even for experienced observers.

The study’s authors argue that the solution lies in redesigning how photo-based records are collected and validated. Reporting tools should record uncertainty explicitly, for example through confidence ratings, rather than forcing a categorical choice that converts doubt into a false definitive claim. Training and outreach materials should deliberately include small-bodied and ambiguous individuals, not just prototypical specimens, so the public learns the true range of variation. Records matching known confusion-prone phenotypes should trigger verification workflows, with expert review and, where feasible, molecular confirmation for atypical individuals or suspected hybrids. Even the rare skipped answer, just 0.62 percent of trials here, could serve as a behavioural signal of ambiguity worth capturing in reporting interfaces. As citizen science takes on a growing role in freshwater fish conservation across Europe, the humble goldfish and its relatives have delivered a clear lesson: in the battle to save the crucian carp, knowing exactly what you are looking at is not a luxury but a conservation necessity.

Subject of Research: Public photo-based identification accuracy of crucian carp, gibel carp, and goldfish and its implications for citizen science monitoring

Article Title: Goldfish, gibel carp, or crucian carp? Testing public recognition of Carassius species

Article References: Gottwald, M., Stepanyshyna, Y., & Šmejkal, M. (2026). Goldfish, gibel carp, or crucian carp? Testing public recognition of Carassius species. Nature Conservation, 65, 135-152. https://doi.org/10.3897/natureconservation.65.185650

Image Credits: AI Generated

DOI: 10.3897/natureconservation.65.185650

Keywords: crucian carp, gibel carp, goldfish, Carassius, citizen science, misidentification, invasive species, freshwater conservation, phenotypic plasticity, species identification, Czech Republic, angling