The study combined field nest collection with laboratory dissection, microscopy, species identification, DNA barcoding and non-parametric statistical comparisons. Sampling at Wenchang occurred during four periods in 2025, while Yongxing Island was sampled during two periods in 2023 and 2024. The researchers collected naturally dead twigs showing entrance holes and wood dust and also placed 30-centimetre, sun-dried S. taccada twigs horizontally in PVC hives near the shrub’s natural habitat. Twig diameter and total nest length were not systematically recorded, limiting analysis of how nest traits relate to particular sizes or classes of twigs.

Five species were identified: Braunsapis hewitti, Ceratina dentipes, Ceratina smaragdula, Ceratina taiwanensis and Heriades sauteri. Morphological identification was supported by mitochondrial COI sequencing; sequences from four species showed more than 98% similarity to conspecific records in GenBank, while C. taiwanensis sequences matched a record identified as Ceratina okinawana taiwanensis. C. smaragdula was the most abundant species in the sample, accounting for 105 nests, or 61.05%. H. sauteri accounted for 38 nests, or 22.09%; C. taiwanensis for 18 nests, or 10.47%; B. hewitti for seven nests, or 4.07%; and C. dentipes for four nests, or 2.33%.

Nest entrance diameter differed significantly among species in a Kruskal-Wallis test (χ² = 89.67, df = 4, p < 0.0001). Mean entrance diameters were 4.13 ± 0.52 mm for C. taiwanensis, 4.08 ± 0.18 mm for C. smaragdula, 3.38 ± 0.40 mm for H. sauteri, 3.20 ± 0.26 mm for B. hewitti and 2.73 ± 0.31 mm for C. dentipes. The two largest means did not differ significantly after Bonferroni-corrected pairwise tests. These measured differences are consistent with resource partitioning, but the study did not experimentally test whether entrance size reduces competition or permits use of different cavity-size classes.

The four species that constructed discrete brood cells also differed significantly in cell number (χ² = 38.72, df = 3, p < 0.0001). H. sauteri and C. taiwanensis averaged 5.29 ± 2.63 and 5.39 ± 3.53 cells per nest, respectively, compared with 2.54 ± 1.68 for C. smaragdula and 2.25 ± 1.89 for C. dentipes. The first two species had significantly more cells than the latter two in corrected pairwise comparisons. The authors did not systematically analyse how sampling season or nest developmental stage contributed to this variation, so differences in maternal investment, reproductive phenology and the number of cells in individual nests cannot be separated.

The species divided into two observed nesting guilds. C. smaragdula, C. taiwanensis and C. dentipes excavated linear tunnels in the soft pith of dead twigs and divided brood cells with thin partitions made from chewed pith. H. sauteri and B. hewitti reused pre-existing abandoned cavities rather than routinely excavating new tunnels. B. hewitti created a single unpartitioned linear brood chamber, with immature bees arranged from the entrance toward the blind end and progressive feeding by the mother. H. sauteri instead used thick, dark-brown resin partitions, firm cylindrical pollen provisions and silken cocoons. The coexistence of excavators and secondary cavity users was observed in the sampled shrub, although the study did not quantify competition or experimentally evaluate niche differentiation.

Social and developmental observations also varied among the species. Female C. dentipes, C. smaragdula and C. taiwanensis guarded nest entrances, and prolonged maternal care was documented for C. smaragdula and C. taiwanensis. Two adult females were occasionally seen together at some C. taiwanensis entrances, suggesting possible facultative semi-social nesting, but the proportion of multifemale nests was not systematically recorded. C. dentipes was represented by only four nests, precluding detailed characterization of its reproductive biology. C. taiwanensis had the most variable cell counts, ranging from one to 11, while H. sauteri also ranged from one to 11.

Microscopic examination of C. smaragdula nest material recovered intact, recognizable pollen grains from pollen-nectar provisions and larval feces. The authors proposed examining both sources to characterize pollen use: provisions reflect material collected by adult females, while larval feces integrate diet across the feeding period. Such nest-based analysis could help future investigators identify pollen sources, although this study did not complete a comparative dietary analysis of all five species or quantify dietary overlap.

Because S. taccada forms dense coastal thickets and produces persistent dead twigs with soft internal pith, the study identifies native coastal shrubs as a potential source of nesting habitat in environments where suitable substrates may be limited. Artificial hives containing cut, sun-dried S. taccada twigs were occupied by bees, demonstrating that the material remained attractive in the researchers’ managed setup. The results therefore support a conservation implication rather than a demonstrated intervention: protecting or restoring native coastal shrubs may help retain nesting resources, and locally sourced twigs could be evaluated in coastal trap-nesting programs. The study did not measure whether shrub protection or artificial deployment increases bee abundance, survival or pollination, nor did it directly evaluate effects of climate warming on the observed Hainan populations.

Subject of Research: Natural-history study of five stem-nesting bee species using Scaevola taccada twigs in coastal Hainan, China

Article Title: Scaevola taccada as a keystone nesting resource for sympatric cavity-nesting bees and its implications for coastal biodiversity conservation

Article References: Liu, Z.-X., Warrit, N., Song, M.-H., Wang, R.-C., Hao, K., Luo, S.-X., & Chen, H.-Y. (2026). Scaevola taccada as a keystone nesting resource for sympatric cavity-nesting bees and its implications for coastal biodiversity conservation. Journal of Hymenoptera Research, 99, 1109-1135. https://doi.org/10.3897/jhr.99.206488

Image Credits: AI Generated

DOI: 10.3897/jhr.99.206488

Keywords: Scaevola taccada, stem-nesting bees, coastal biodiversity, Hainan Island, nest architecture, cavity-nesting bees, Ceratina, Heriades sauteri, Braunsapis hewitti, pollinator conservation, Scaevola, taccada

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

Türkiye hosts more than 1,800 recorded bee species, making it amongst the most diverse regions in the Western Palaearctic and a presumed centre of diversity, and possibly even a region of origin, for several bee groups. The country’s remarkable habitat diversity, spanning Mediterranean shrublands, steppes, marshes, halophilic grasslands and subalpine and alpine grasslands, combined with a high level of plant endemism, presumably supports a correspondingly high level of bee endemism. Yet despite this richness, the national fauna remains broadly incomplete, as evidenced by the dozens of species that have been described or newly reported from the country over the last years alone.

The expedition, carried out in Spring 2025, covered 42 sites distributed across southern Türkiye: 38 in the Mediterranean Region, in the provinces of Adana, Antalya, Mersin and Osmaniye, and four in the south of the Central Anatolia Region, in Karaman and Konya. Sampling sites were selected using searches in Google Maps for potential high-quality habitats, mainly sites surrounded by ample natural habitats, followed by on-site surveys to confirm the presence of sufficient floral diversity for attracting a high diversity of bees. Wild bees were collected using hand nets, with collectors prioritising species diversity by sampling on a maximum diversity of flowering plants. Sampling generally ran from 9 a.m. to 5 p.m., and specimens were killed with cyanide or ethyl acetate and pinned in collection the same day, each labelled with locality, altitude, GPS coordinates, date, collector and a unique identification code.

Species-level identification was performed in the lab by a team of 18 specialists, each responsible for particular genera or groups, including Thomas Brau for Halictus and related genera, Frédéric Carion for Nomada, Achik Dorchin for Eucera, Simone Flaminio for Lasioglossum and related genera, Guillaume Ghisbain for Bombus and Dasypoda, Michael Kuhlmann for Colletes, Andreas Müller for Chelostoma, Hoplitis and Osmia, Pierre Rasmont for Amegilla, Anthophora and related genera, Jakub Straka for Nomada and Sphecodes, Michaël Terzo for Ceratina and Xylocopa, Clément Tourbez for Megachile and related genera, and Thomas J. Wood for Andrena, Camptopoeum and Panurgus. Reference material from the collection of the Laboratory of Zoology at the University of Mons in Belgium and from each expert’s personal research collection was used to achieve the identifications. Where conflicting identifications were provided by different experts, these were specified in the identification remarks column of the dataset.

The geographical consistency of the identifications was first verified for each species using centralised resources, then additional targeted documentation was sought and a double-check of the identifications was carried out by Rémi Santerre to confirm the validity of the taxa found outside of their known range. The complete dataset covers 246 confidently identified species belonging to the six bee families present in the Palaearctic Region: Andrenidae, Apidae, Colletidae, Halictidae, Megachilidae and Melittidae. It includes another seven taxa for which the uncertain species identity is marked by the notations ‘cf.’, ‘aff.’ or ‘gr.’, indicating uncertain identification, close relationship to a mentioned species, or membership of a species-group. In addition, 112 specimens remain unidentified, representing between 27 and 42 recognisable taxonomic units, some of which may correspond to species already identified. These unidentified specimens are distributed amongst the genera Amegilla, Andrena, Anthophora, Chelostoma, Eucera, Halictus, Lasioglossum and Seladonia, with Andrena alone accounting for 26 specimens and between 10 and 23 recognisable taxonomic units.

Amongst the six species new for the fauna of Türkiye, Andrena igraeca is a recently described species whose presence in the Hatay Province was presumed due to a record in north-west Syria. It is now confirmed to occur in Türkiye by 13 specimens collected in three locations in the Nur Mountains, near to the Hatay Province, at elevations ranging from 1,346 to 1,926 metres. Anthophora dalmatica, known from south-eastern Europe and Western Asia, was represented by two males collected in a Cistus-rich shrubland near Anamur in Mersin Province. Although the boundaries of its distribution are unclear due to the unresolved taxonomy of the species-group to which it belongs, its presence in Türkiye was likely, as it occurs in the surrounding areas. Existing records of Anthophora atroalba from Türkiye might actually pertain to this species.

Anthophora subterranea, a polytypic circum-Mediterranean species with numerous synonyms, was represented by a single female collected in the Nur Mountains at 1,926 metres, at the border with Hatay Province. Despite being relatively common, none of its numerous synonym names has been reported yet from Türkiye to the best of the authors’ knowledge. Eucera parnassia, already known from several surrounding countries including neighbouring Aegean islands, was represented by five females collected in a Brassicaceae-rich meadow in a valley near İbradi in Antalya Province. Eucera parvicornis, belonging to the small subgenus Cubitalia composed of eight species of which most are primarily distributed in Western Asia, was represented by one female and four males collected near Geçimli in Mersin Province at 1,235 metres. This species is oligolectic on Boraginaceae with a preference for Anchusa and is considered Near Threatened in Europe.

Osmia jason, the sixth species new for Türkiye, belongs to the subgenus Neosmia, whose members build their nests in empty snail shells. Its complex nesting behaviour is explained in detail in earlier taxonomic work: the cell partition is made with leaf pulp and the entry is sealed with a three-layer final plug of leaf pulp, mineral materials and leaf pulp; the shell is plastered with leaf pulp, buried in the ground and covered with dried plant material. The five females were collected on flower-rich grasslands in orchards from two locations near Adana, at elevations of 107 and 140 metres. Beyond the six new country records, the expedition also highlighted species of particular conservation interest in neighbouring regions. Ammobatoides abdominalis, considered Vulnerable in Europe and distributed from Central Europe to western China and southern Siberia, was represented by a single male collected near Güzelyalı in Antalya Province. Three specimens of Melitturga syriaca, a presumed host, were found at the same location. Lasioglossum laeve, also considered Vulnerable in Europe, was represented by a single female collected in the Nur Mountains at 1,926 metres.

Several additional noteworthy species of taxonomic and biogeographical interest were documented. Andrena etesiaca, closely related to Andrena bassana and formerly considered a subspecies of it, seems to be restricted to central Türkiye, where it is known from a very limited number of specimens; the new records come from Ereğli in Konya Province at 1,112 metres. Ceratina denesi was described based on a single male specimen collected in Silifke in 1995, and no other records have been published since then apart from a putative female identified near Antalya in 2002. The four males collected near Alaçeşme are larger than the holotype, but the shape of tergum 7, the absence of concavity on the apical half of the clypeus and overall blue colouration separate it from the similar species Ceratina loewi and Ceratina cypriaca.

Perhaps the most unexpected finding was Ceratina rasmonti, previously known only from the four females constituting the type series, collected in Erçek and Ağrı in eastern Türkiye at an altitude of around 1,800 metres. The finding of this species in south-western Türkiye, at 478 metres near Beydiğin and 956 metres near İbradi, was therefore surprising. The new specimens have the tibiae less extensively white-marked than the type specimens and were first misidentified as Ceratina dallatorreana, a related and much more common species. The two species could be distinguished only after a second careful examination, Ceratina rasmonti having sparser punctation on the scutum and between the ocelli, a depressed ocello-occipital area, a carinate occipital margin and less developed wax glands on sternum 3 than Ceratina dallatorreana. This suggests that this presumably rare species might be under-recorded due to the difficulty in detecting it amongst series of Ceratina dallatorreana, a cautionary reminder that even well-collected faunas can conceal species in plain sight.

Subject of Research: Biodiversity

Article Title: New records of wild bees from a spring expedition in southern Türkiye, with six new species for the country ( Hymenoptera , Apoidea , Anthophila )

Article References: Santerre, R., Michez, D., Aytekin, A., Aytekin, S., Benrezkallah, J., Brau, T., Carion, F., Dikmen, F., Dorchin, A., Eldem, V., Flaminio, S., Hopfenmüller, S., Kamalak, E., Maugendre, A., Özenirler, Ç., Rasmont, P., Rigaut, B., Terzo, M., Tourbez, C., & Ghisbain, G. (2026). New records of wild bees from a spring expedition in southern Türkiye, with six new species for the country (Hymenoptera, Apoidea, Anthophila). Biodiversity Data Journal, 14, Article e191847. https://doi.org/10.3897/bdj.14.e191847

Image Credits: AI Generated

DOI: 10.3897/BDJ.14.e191847

Keywords: wild bees, Türkiye, biodiversity, pollinators, new species records, Mediterranean, taxonomy, conservation, records, wild, bees, spring

Traditionally, rust fungi are understood to disperse primarily through wind or water, relying on the production of vast quantities of small, lightweight urediniospores adapted for aerial transport. However, recent field observations have challenged this singular view of abiotic dispersal. Researchers have documented Western honey bees, Apis mellifera, actively collecting urediniospores of A. psidii from infected host plants. These foragers store the spores in their pollen baskets and return them to the hive in a manner that is visually and behaviorally indistinguishable from standard pollen foraging. This behavior suggests a potential novel mutualistic interaction between two alien species, where the fungus gains a new mode of dispersal and the bee may obtain an alternative source of nutrition.

To validate this hypothesis, researchers investigated two critical conditions required for such a mutualism to function: whether the spores remain viable after entering the hive environment and whether they provide a nutritional benefit to the pollinator. The study focused on the persistence of A. psidii urediniospores within honey bee colonies and their nutritional composition. By testing these factors, the team aimed to determine if spore foraging is a viable strategy for honey bees rather than an aberration, and if this interaction could facilitate the long-distance dispersal of the pathogen.

The results indicated that A. psidii spores remain viable for at least nine days within honey bee colonies. In controlled trials, spores placed in hives maintained germination rates comparable to initial levels, showing no significant decline in viability over the nine-day period. This persistence is particularly concerning given that commercial hives are frequently transported over long distances for agricultural pollination services, typically within a three-to-seven-day window. The survival of viable spores during this timeframe suggests that managed hives could act as a significant vector for the pathogen, a pathway not currently incorporated into existing biosecurity frameworks.

Nutritional analysis revealed that A. psidii urediniospores match or exceed the nutritional quality of known high-protein pollens. The spores contained 22.5% protein, which is comparable to willow pollen and significantly higher than other fungal spores tested. Furthermore, the spores contained all ten essential amino acids required for honey bee development in amounts above the minimum thresholds for full protein absorption. These findings suggest that the spores are not merely contaminants but a potentially valuable dietary resource for the bees, especially in environments where floral resources are scarce due to drought, habitat loss, or the rust infection itself.

Artificial rearing trials further demonstrated that A. psidii spores support normal development and survival in honey bee brood. Larvae fed diets containing the rust spores developed at rates and achieved weights similar to those fed high-quality pollen sources. While survival rates were slightly lower than those on kiwifruit pollen, they remained well above the minimum thresholds for colony health. In contrast, larvae fed spores from a different rust species, Melampsora sp., showed reduced survival and lower body weight, indicating that not all fungal spores are equal in their nutritional value to bees. The specific amino acid balance in A. psidii spores appears to be key to their suitability as a food source.

This interaction exemplifies an “invasional mutualism,” a phenomenon where introduced species facilitate each other’s success, often exacerbating the speed and scale of invasion. In this case, the rust gains a new mode of urediniospore dispersal, while the bee obtains an alternative source of protein. This dynamic could create a positive ecological feedback loop: as myrtle rust reduces floral resources, bees may increasingly turn to fungal spores for nutrition, thereby enhancing the pathogen’s spread and further depleting the floral resources that support pollinator networks. Such a cycle could destabilize plant-pollinator interactions and forest regeneration, particularly in regions with high Myrtaceae endemism.

The implications for biosecurity are significant. Current national and regional strategies, such as the Australian Myrtle Rust Action Plan and New Zealand surveillance plans, do not yet include the potential of apiculture in the spread of plant pathogens. Recognizing pollinators as potential vectors is essential for developing more effective containment strategies. Integrating pollinator movement into management plans could help limit the geographic expansion of A. psidii and protect biodiversity in vulnerable areas. Future research should experimentally test the final condition for mutualism: successful infection of a new host following pollinator-mediated dispersal. Quantifying the relative contribution of insect-mediated versus windborne dispersal across different landscapes and seasons will be vital for forecasting future spread and designing evidence-based interventions.

Subject of Research: Honey bees as potential vectors of the invasive rust pathogen Austropuccinia psidii: nutritional mutualism and implications for pathogen spread

Article Title: Honey bees as potential vectors of the invasive rust pathogen Austropuccinia psidii : nutritional mutualism and implications for pathogen spread

Article References: Shin-Clayton, S., Mortensen, A. N., Beggs, J. R., Buxton, M. N., Hauxwell, C., Bateson, M. F., Jochym, M., Pegg, G. S., & Pattemore, D. E. (2026). Honey bees as potential vectors of the invasive rust pathogen Austropuccinia psidii: nutritional mutualism and implications for pathogen spread. NeoBiota, 106, 75-90. https://doi.org/10.3897/neobiota.106.169027

Image Credits: AI Generated

DOI: 10.3897/neobiota.106.169027

Keywords: Honey, bees, potential, vectors, invasive, rust, pathogen, Austropuccinia, psidii, nutritional, mutualism, implications

The mismatch between who visits and who actually pollinates is one of the most striking patterns to emerge from the study. Across 73 recorded visitation events on Calanthe discolor, flies in the order Diptera made up the bulk of the traffic, yet not a single fly or butterfly left the flowers carrying pollinaria. This pattern illustrates a central challenge in food-deceptive pollination systems: attracting visitors is relatively easy, but converting visits into pollen transfer is not. In deceptive orchids, insects that land on flowers expecting a reward quickly learn or simply fail to make the deep, sustained probing movements needed to contact the reproductive structures. The orchid’s pollinaria, with their sticky adhesive pads, attach only when an insect pushes deep into the floral spur, and shallow or brief visits simply do not produce that contact.

The bees that did carry pollinaria on C. discolor — the mining bee Andrena opacifovea, the Asian honeybee Apis cerana, the small carpenter bee Ceratina japonica and the sweat bee Lasioglossum formosae — represent a taxonomically diverse set of hymenopterans rather than a single specialised partner. This breadth matters for the orchid’s ecology. Generalised food deception, in which a plant mimics the general signals of rewarding flowers without imitating any specific model species, tends to attract a broad but inefficient visitor pool. The Korean observations fit this model well: many insects came, few carried pollen, and the effective pollinators were medium-to-large bees capable of probing deeply into the spur. This aligns with earlier work in Japan and China, where carpenter bees, long-horned bees, bumblebees and sweat bees have been documented as the principal pollinators of various Calanthe species.

Food deception is widespread among orchids and carries well-documented ecological consequences. Because visitors receive no reward, they tend to learn to avoid the deceptive flowers after one or a few unrewarded encounters, which typically depresses visitation rates and fruit set compared with rewarding plants. Deceptive orchids compensate in various ways — through variability in floral display, through exploiting newly emerged or naive insects, and through the sheer longevity of individual flowers, which can remain receptive long enough to accumulate rare effective visits. The low frequency of pollinaria-carrying visitors recorded in the Korean study is consistent with this broader picture: even during peak flowering on clear, sunny days chosen specifically to maximise insect activity, effective pollinator visits were rare events.

The single observation on C. striata is scientifically significant precisely because it is so sparse. One visitation event by the long-horned bee Eucera nipponensis, with pollinaria attached to the head and the insect moving between flowers, mirrors findings from Japan where the same species has been recorded pollinating hybrids between C. discolor and C. striata. Head-borne pollinaria are particularly consequential in orchids because their placement determines where pollen can be deposited on the next flower visited. If E. nipponensis forages across both taxa in Korean populations, as the Japanese evidence suggests it might, then pollen could move between the species, creating opportunities for hybridisation. This is a testable hypothesis rather than a demonstrated fact — the authors are careful to frame it that way — but it provides a concrete direction for future fieldwork involving more sites, longer observation windows and multiple flowering seasons.

The question of pollinator sharing carries real evolutionary weight. Closely related orchid taxa flowering in sympatry face a fundamental tension: shared pollinators can facilitate gene flow that erodes species boundaries, while pollinator partitioning can reinforce reproductive isolation. In orchids, where hybridisation is a well-known evolutionary force, the identity and behaviour of pollinators can therefore shape whether closely related species remain distinct or blend together. Korean botanical literature has long treated C. striata as a putative natural hybrid of C. discolor and C. sieboldii, and the two focal taxa of this study occur together on Jeju Island, where C. striata shows extensive morphological variation. Genetic work has already established that C. discolor and C. striata are closely related. Documenting which insects actually transport pollinaria between them is thus an essential first step toward understanding the reproductive dynamics of this system in Korea.

The fieldwork itself reflects the practical realities of studying pollination in shaded forest understoreys. Both study sites — a mixed forest on Anmyeon Island on the west coast and dense Japanese cedar stands at Darangswi Oreum on Jeju Island — shared a dense canopy that produced a shifting mosaic of sunflecks on the forest floor. Because insect activity tracks these ephemeral patches of light and warmth, the four trained observers moved continuously between orchid patches rather than remaining fixed at single plants. The surveys were timed to peak bloom, defined as the point when more than half the florets on each raceme were open, and conducted over twelve-hour spans from morning to evening on clear days in late April and early May, when ambient temperatures hovered around 15 degrees Celsius. Capturing insects only as they departed the inflorescences minimised disturbance, and every specimen was later re-examined under a stereomicroscope to confirm the presence or absence of pollinaria, with voucher specimens deposited at the Korea National Arboretum.

One methodological caveat deserves attention: because visitors were not individually marked and not all could be captured, the counts represent visitation events rather than unique individuals, and the same insect may have been recorded more than once. This is a standard and honest limitation of field pollination studies, but it means the true number of visiting insects could differ from the raw event counts. Similarly, a single season at two sites cannot capture the full temporal and geographic variation in pollinator assemblages, which is precisely why the authors present their results as baseline evidence and hypothesis-generating observations rather than definitive conclusions about pollinator identity across the Korean range of these orchids.

The conservation context adds urgency to this line of research. Calanthe species are prized ornamentals, and overcollection combined with habitat destruction has driven declines in wild populations, placing some species at risk. In South Korea, seven Calanthe species are recorded, and several carry formal conservation designations: C. aristulifera is listed as a Class II Endangered Wildlife species, while C. reflexa and C. sieboldii are classified as Endangered in the Korean National Red List. These orchids are largely restricted to the understorey of evergreen broad-leaved forests on the southern coastal islands and Jeju Island, where a mild oceanic climate prevails — habitats that are themselves limited and increasingly fragmented. Although artificial propagation techniques have been developed to support ex situ conservation, reintroduced or managed populations ultimately depend on natural pollination for long-term persistence. Understanding which insects actually move pollen, and under what conditions, is therefore not merely an academic question but a practical prerequisite for effective conservation planning.

The study also highlights how much basic pollination ecology remains undocumented even in well-studied temperate regions. Prior to this work, field data on floral visitor assemblages and pollinaria transport in wild Korean Calanthe populations were essentially absent, with only one recent field-based study of C. aristulifera providing a domestic point of comparison. The genus Calanthe comprises roughly 200 species of perennial terrestrial orchids distributed across Africa, Madagascar, China, Japan, tropical Asia and Australia, and only about eight species are known to self-pollinate, leaving the vast majority dependent on cross-pollination by animals. For most of these species, the identity of effective pollinators remains unknown or inferred from a handful of observations. Each regional study, such as this one, fills in a piece of that global picture while revealing how locally variable pollinator assemblages can be.

Looking forward, the framework established here suggests several productive avenues. Broader temporal sampling across multiple flowering seasons would reveal whether the bee-dominated pollinaria transport seen in 2025 is consistent year to year or reflects the particular conditions of a single spring. Population-level replication across the scattered island and coastal habitats where Korean Calanthe occur would show whether pollinator sharing between C. discolor and C. striata is geographically widespread or restricted to sites of sympatry such as Jeju Island. Direct tracking of pollen movement, whether through marked pollinaria or genetic paternity analysis, could confirm whether Eucera nipponensis and other shared visitors actually mediate gene flow between the taxa. And because the dataset underpinning the study has been deposited with the Global Biodiversity Information Facility, other researchers can independently examine and build upon the occurrence records. In the meantime, the study delivers a clear and useful message: in these deceptive Korean orchids, abundance of visitors is no measure of reproductive success, and the fate of each flowering season rests on the behaviour of a small, select guild of bees.

Subject of Research: Floral visitors and potential pollinators of the deceptive orchids Calanthe discolor and Calanthe striata in South Korea

Article Title: Floral visitors and potential pollinators of Calanthe discolor and C. striata in South Korea

Article References: Han, G. Y., Euo, S.-S., Son, S., Lee, H.-S., Choi, K., & Kim, C.-J. (2026). Floral visitors and potential pollinators of Calanthe discolor and C. striata in South Korea. Biodiversity Data Journal, 14, Article e201540. https://doi.org/10.3897/bdj.14.e201540

Image Credits: AI Generated

DOI: 10.3897/BDJ.14.e201540

Keywords: Calanthe discolor, Calanthe striata, food-deceptive orchids, pollination ecology, pollinaria transport, Eucera nipponensis, bees, South Korea, Orchidaceae, field observation, pollinator sharing, biodiversity

The story began in May 2024, when a single male A. onosmarum was captured in Bulgaria visiting flowers of the plant genus Onosma, a group of Boraginaceae known for their deep, tubular blossoms. Just weeks later, in June 2024, a targeted search in northern Greece revealed a thriving population: roughly ten males and five females patrolling and feeding among clumps of Onosma on dry slopes between 600 and 1000 metres above sea level. The researchers visited around twenty sites in the region, and the bee turned up at only one of them, hinting at how local and sporadic its appearance really is.

What makes the find even more striking is that the bee is not exactly small. A. onosmarum is a member of the genus Anthophora, which contains around 430 species worldwide and 77 in Europe, making it the seventh largest bee genus on the continent. A bee of this size, with distinctive yellow facial markings in the male and a metasoma covered in either pale yellow-orange or black pubescence in the female, somehow slipped past generations of European entomologists. The researchers suspect that the species was simply overlooked, mistaken for other similar-looking Anthophora or not recognised because no modern identification key exists for the genus in south-eastern Europe.

Museum collections helped fill in the picture. Searches turned up 23 previously unidentified specimens, including a male collected in Bulgaria as far back as 1987, sitting undetermined in the collection of the Oberösterreichisches Landesmuseum in Linz, Austria. The other specimens came from Turkey, Iran, and Georgia, confirming that the species is widespread across the Anatolian plateau and beyond. With altitude data available for some records, the bee is known to occur between 420 and 2200 metres above sea level, with most records above 1000 metres.

To confirm the identification, the team generated a full-length DNA barcode from a Greek male specimen. When compared against the Barcode of Life Data System, the closest matches were to other Anthophora species, but the barcode was clearly distinct from all others represented in the database. Tree-based analysis tentatively suggested that A. onosmarum is sister to a clade containing A. balneorum and A. nigrovittata, offering a first glimpse of its phylogenetic affinities.

The behavioural observations are perhaps the most exciting part of the story. The researchers watched females hang upside down from Onosma corollas, using their remarkably long tongues to reach the nectaries deep inside the flowers. Then came the buzz. The females were heard emitting a short, high-pitched vibration while gripping the flower tightly, and pollen could be seen falling onto the underside of their metasoma as they released their grip. This is buzz pollination, a technique more commonly associated with bumblebees, and it allows the bee to shake pollen loose from the anthers in a way that scraping alone cannot achieve.

Based on this behaviour, the bee’s long tongue, and its strong association with Onosma, the researchers consider A. onosmarum likely to be narrowly oligolectic, meaning it depends on a single plant genus for pollen. This kind of specialisation makes the bee vulnerable to changes in the availability of its host plant, and it also makes the discovery ecologically significant. Other Boraginaceae-associated bees show a range of strategies, from the broadly oligolectic Osmia apicata, which scrapes pollen with its forelegs, to buzz-pollinating specialists like Hoplitis onosmaevae and Eucera breviceps, which seem to be narrow oligoleges of Onosma.

The colour variation observed in females adds another layer of intrigue. Of nine female specimens examined, four showed black pubescence and five showed yellow pubescence, with a weak geographic gradient of darker individuals in the west and lighter ones in the east. Remarkably, two females of different colour morphs were collected at the same site in Turkey on separate occasions. The researchers make no decisive comments on the cause, noting only that the variation seems to be simple colour polymorphism, not accompanied by structural differences. Males, by contrast, appear much more consistent in colouration, fitting a broader pattern of reduced colour variation in male anthophorines.

The discovery fits into a growing trend. In recent years, several bee species with Caucasian, Anatolian, or Middle Eastern distributions have been turning up in under-surveyed mountainous parts of the Southern Balkans. The newly described Hoplitis onosmaevae, ranging from southern France to Turkey and northern Iraq, and the eucerine bee Eucera breviceps, newly reported for western Europe, both tell a similar story. The researchers suggest that A. onosmarum is almost certainly present in Albania and North Macedonia as well, given its known locality in north-western Greece.

For now, the bee remains rare and local in the Balkans, despite the wide distribution and abundance of its host plants. The researchers hope that a revised identification key to European Anthophora will be produced in the near future, making it easier for others to recognise this and other overlooked species. In the meantime, the discovery serves as a reminder that even large, distinctive bees can hide in plain sight, waiting for someone to look closely at the right flowers on the right dry slope at the right time of year.

Subject of Research: Discovery of Anthophora onosmarum Morawitz, 1876 in Europe (Hymenoptera, Apidae)

Article Title: Discovery of Anthophora onosmarum Morawitz, 1876 in Europe ( Hymenoptera , Apidae )

Article References: Wood, T. J., & Praz, C. J. (2024). Discovery of Anthophora onosmarum Morawitz, 1876 in Europe (Hymenoptera, Apidae). Alpine Entomology, 8, 153-160. https://doi.org/10.3897/alpento.8.138225

Image Credits: AI Generated

DOI: 10.3897/alpento.8.138225

Keywords: bees, entomology, biodiversity, conservation, Europe, oligolectic, Discovery, Anthophora, onosmarum, Morawitz, Hymenoptera, Apidae

The haploid chromosome numbers recorded for bees range from three to twenty-eight, a span that Owen argues probably represents the true range for the entire group. The most common count, the modal number, is seventeen, with a second peak at nine that reflects a single well-studied clade of stingless bees, the Meliponini. That bimodal distribution is itself instructive, because it shows how sampling bias can shape apparent patterns: more than half of all bee chromosome counts come from the meliponids, so the prominence of n equals nine is partly an artifact of where cytogeneticists have concentrated their efforts. Still, the underlying signal seems real, and it points to a broad evolutionary trend from low chromosome numbers in some lineages toward higher numbers in others.

That trend is best understood through the lens of the Minimum Interaction Theory, proposed by Hirotami Imai and colleagues to explain karyotype evolution in ants, bees and wasps. The theory holds that chromosome evolution proceeds in cycles: a centric fission splits one chromosome into two, reducing the size of each and thereby minimizing deleterious interactions between chromosomes during cell division. Over time, heterochromatin accumulates on one arm of the resulting fragments, and pericentric inversions can convert acrocentric chromosomes back into metacentrics. The net prediction is that chromosome numbers should tend to increase over evolutionary time, starting from a low ancestral count. Evidence from across the Hymenoptera supports this general picture, with the ancestral haploid number for the order estimated at eight or fewer, and many lineages having climbed steadily upward through repeated fissions.

Bees broadly conform to this pattern. The families Apidae, Colletidae, Halictidae and Megachilidae all show modal haploid numbers of sixteen or seventeen, consistent with an ancestral low number that has been increased by fission. But the pattern is not universal. The stingless bees, a highly social clade within the Apidae, have a modal number of nine, which is lower than their closest relatives and difficult to reconcile with a simple fission-driven trajectory. Owen notes that chromosome evolution in the Meliponini cannot be explained by a single process, and that while the Minimum Interaction Theory fits some taxa within the group, it fails for others, particularly the genus Melipona itself, where chromosome numbers are low and heterochromatin distribution does not follow the expected pattern.

The review also highlights how much remains unknown. Only twenty-eight species have been karyotyped across the four families Andrenidae, Colletidae, Halictidae and Megachilidae combined, and the single andrenid species examined, Andrena togashii, happens to have one of the lowest chromosome counts in all of bees, with a haploid number of just three. Owen argues that obtaining counts from additional andrenid species is essential to determine whether this is an isolated anomaly or a broader feature of the family, and to further test the Minimum Interaction Theory’s prediction of increasing chromosome number. Unpublished data from a doctoral dissertation suggest at least one other Andrena species also has a low count, hinting that the pattern may be real, but these observations have not appeared in the primary literature and are not included in the Bee Chromosome Database, an online resource that aggregates chromosome numbers and genome sizes for bee species worldwide.

Chromosome size and number are generally inversely related, a relationship that reflects the simple fact that the total amount of genetic material must be packaged somehow. The andrenid Andrena togashii, with only three chromosomes, has individual chromosomes that are relatively long, while the colletid Hylaeus species with twenty-eight chromosomes has chromosomes that are all quite short. Yet genome size itself shows no clear relationship with chromosome number across the Hymenoptera, a manifestation of the long-recognized C-value paradox. Hymenopteran genome sizes range from about 0.1 to 1.14 picograms, and the eighteen bee species for which data are available average 0.57 picograms, with no obvious correlation with how many chromosomes carry that DNA.

One of the most intriguing observations in the review concerns the social parasitic bumble bees of the subgenus Psithyrus, commonly known as cuckoo bumble bees. These bees, which invade the colonies of their Bombus relatives and rely on chemical mimicry to avoid detection by host workers, have a strikingly high haploid chromosome number of twenty-five, well above the modal eighteen found across the rest of the genus. Owen proposes a hypothesis to explain this: the high chromosome number may reduce the variance in the fraction of genes that are identical by descent among a queen’s female offspring, making them more uniform in traits such as cuticular hydrocarbon profiles, which are the chemical signatures that hosts use to recognize intruders. A more uniform brood would be better at blending in, giving the parasite’s offspring a selective advantage. The hypothesis is admittedly speculative, but it is testable, and Owen notes that it would be disproved if Psithyrus offspring turn out not to be unusually uniform in their chemical profiles.

Beyond chromosome counting, more sophisticated cytogenetic techniques are beginning to reveal the fine structure of bee genomes. Fluorescence in situ hybridization has been used to map ribosomal DNA and microsatellite sequences in Neotropical stingless bees, and genomic approaches are now identifying chromosomal rearrangements such as inversions directly from sequence data. In honeybees, for example, genomic studies have detected large inversion blocks on chromosomes seven and nine that differ between highland and lowland populations in Kenya and appear to be maintained by balancing selection, potentially carrying genes involved in foraging behavior. These tools promise to move the field beyond simple counts and toward a mechanistic understanding of how chromosomal architecture evolves and what adaptive significance it may hold.

The review makes clear that bee cytogenetics is a field with far more questions than answers. With over twenty thousand described bee species and chromosome counts for barely one percent of them, the sampling is thin enough that even the modal number of seventeen could shift as new data accumulate. Yet the framework provided by the Minimum Interaction Theory, combined with the growing power of genomic methods, offers a path forward. As Owen concludes, applying these techniques to other taxa of bees will undoubtedly reveal features of great interest, and the potential adaptive value of chromosome number itself remains one of the most compelling open questions in the field.

Subject of Research: Chromosome number evolution and karyotype diversity in bees

Article Title: Chromosome evolution in bees

Article References: Owen, R. E. (2025). Chromosome evolution in bees. Frontiers in Bee Science, 3, Article 1395037. https://doi.org/10.3389/frbee.2025.1395037

Image Credits: AI Generated

DOI: 10.3389/frbee.2025.1395037

Keywords: bees, chromosomes, karyotypes, Hymenoptera, cytogenetics, Minimum Interaction Theory, stingless bees, bumble bees, honeybees, chromosomal inversions, genome size, social parasitism

The research team, led by Willams Oliveira of the Universidade Federal de Pernambuco together with colleagues in Recife and at the University of East Anglia, focused on three native Brazilian crops chosen for a shared vulnerability: they are all self-incompatible, meaning they depend on cross-pollination to produce fruits and seeds, and yields collapse by at least 90% in the absence of pollinators. The trio comprises passionfruit (Passiflora edulis), the Brazil-nut tree (Bertholletia excelsa) and pitanga, also known as Brazilian cherry (Eugenia uniflora). Each was paired with its main effective pollinator: the large carpenter bee Xylocopa frontalis for passionfruit, the orchid bee Eulaema mocsaryi for Brazil-nut, and the European honeybee Apis mellifera for pitanga.

The stakes are considerable. Passionfruit carries an estimated annual Economic Value of Pollination of roughly US$284.5 million in Brazil, Brazil-nut about US$75.6 million, and pitanga around US$264,600. Brazil ranks among the world’s largest agricultural producers and exporters, and 60% of its crops depend on animal pollinators. Yet the country returned to the FAO hunger map in 2021, with more than 60 million people facing moderate to severe food insecurity in 2020 — a backdrop that makes any threat to pollination services a matter of national concern rather than an abstract ecological worry.

Technically, the study rests on species distribution modeling, a family of statistical approaches that relate georeferenced occurrence records to environmental variables to map where a species’ climate niche is currently suitable — and where it will remain suitable under future climates. The team compiled 3,479 plant and 2,241 pollinator occurrence coordinates from the Global Biodiversity Information Facility, the REFLORA virtual herbarium and the BIEN plant database. Climate surfaces came from WorldClim 2.1 at 2.5-minute resolution, covering the contemporary baseline of 1970–2000 and the 2081–2100 window drawn from the Coupled Model Intercomparison Project Phase 6, which the authors note exhibits heightened climate sensitivity compared with its predecessors.

Rather than betting on a single emissions trajectory, the researchers ran projections under three Shared Socioeconomic Pathways: SSP2-4.5, the optimistic

…continues SSP1-2.6, which assumes strong emissions reductions and roughly 1.8 degrees Celsius of warming by 2100; SSP2-4.5, an intermediate pathway in which emissions peak around mid-century before declining; and SSP5-8.5, a fossil-fuel-intensive scenario associated with warming approaching 4 degrees Celsius or more. Running the same models across all three pathways allowed the researchers to bracket the plausible range of futures rather than stake their conclusions on a single trajectory, and the negative signal held in every case.

The modeling machinery behind these projections deserves a closer look, because species distribution models are only as trustworthy as their construction. The team used an ensemble approach, combining multiple algorithms rather than relying on any single method, and validated each model against held-out occurrence data before projecting into future climates. Ensemble modeling matters because different algorithms can disagree about where a niche is suitable; averaging across them, and across the multiple global climate models available for each emissions scenario, smooths out the idiosyncrasies of any one method. The researchers also accounted for spatial autocorrelation in the occurrence records, a common pitfall that can inflate measures of model performance when nearby records share similar environmental conditions.

What emerged from the projections was a consistent pattern of contraction. Under all three scenarios, every one of the six species — three plants and three bees — was projected to lose suitable habitat, with losses intensifying as emissions rose. But the more consequential finding concerned overlap: the areas where a plant and its pollinator would both still find suitable conditions shrank more than either species’ range alone. For the Brazil-nut tree and its orchid bee pollinator Eulaema mocsaryi, the projected loss of shared suitable habitat reached 76 percent, the steepest of the three pairings. Passionfruit and the carpenter bee Xylocopa frontalis lost 51.5 percent of their overlapping area, while pitanga and the honeybee Apis mellifera lost 54 percent.

That asymmetry between individual range loss and joint range loss is the study’s central insight, and it stems from a simple geometric reality. When two species respond differently to changing climate — shifting their ranges in different directions, at different speeds, or contracting around different refugia — the zone where both persist is squeezed from both sides simultaneously. A plant might retain habitat in one region while its pollinator retains habitat in another, leaving each species biologically viable in isolation but reproductively stranded where it matters. For self-incompatible species, this is the crux: a population of passionfruit vines surviving in a climatically suitable pocket is of little use if the carpenter bees that move pollen between flowers have vanished from the same landscape.

The three pollinators themselves represent very different biologies, which strengthens the generality of the findings. Xylocopa frontalis is a large carpenter bee that buzz-pollinates, vibrating flowers at specific frequencies to shake pollen loose from pores — a service that passionfruit flowers, with their enclosed anthers, structurally demand. Eulaema mocsaryi is an orchid bee, a group of long-tongued, often solitary bees renowned for the males’ collection of fragrances, and it serves as the principal effective pollinator of the Brazil-nut tree, whose flowers are enclosed in a hooded structure that only sufficiently strong and appropriately shaped visitors can access. Apis mellifera, the European honeybee, is the world’s most managed pollinator and the backbone of commercial pollination services. The study’s finding that even this generalist, human-subsidized species faces substantial habitat contraction under future climates is particularly sobering, since managed hives cannot easily compensate when the underlying climate envelope of a region shifts beyond the species’ tolerance.

The Brazil-nut case carries implications beyond agriculture. Bertholletia excelsa is a canopy giant of Amazonian forests, and its regeneration depends on large-bodied bees capable of traversing the distances between widely scattered flowering trees. Orchid bees are also sensitive to deforestation, and the same landscapes that will lose climatic suitability for Eulaema mocsaryi are already under pressure from logging and land conversion. A 76 percent contraction in the area where tree and bee co-occur suggests that natural regeneration of one of the Amazon’s most economically and culturally significant trees could falter even in areas where the trees themselves might otherwise persist — a reminder that climate-driven mismatches can undermine forest dynamics, not just orchard yields.

Several caveats temper the projections. Species distribution models assume that current occurrence records reflect climatic tolerances, yet bees and plants may adapt physiologically or behaviorally to warming over decadal timescales. The models also treat each species independently, without explicitly simulating dispersal, competition, or the phenological timing of flowering and bee flight seasons — mismatches in seasonal timing, as distinct from geographic mismatch, represent an additional layer of risk the modeling framework cannot capture. Occurrence records for tropical insects are also sparser than for plants, which can widen uncertainty in pollinator niche estimates. The authors frame their results as plausible scenarios rather than deterministic forecasts, and the direction of the signal — consistent negative responses across all species and scenarios — is arguably more robust than any single percentage figure.

For agricultural planning, the practical implications point toward protecting and restoring climatic refugia where plant-pollinator overlap is projected to persist, maintaining habitat connectivity so that bees can track shifting suitable zones, and diversifying the pollinator communities associated with vulnerable crops so that no single species’ decline is catastrophic. The study adds to a growing body of evidence that the unit of conservation concern for pollination services is not the species but the interaction — and that interactions, being doubly exposed to the independent climate responses of two organisms, may be the most fragile link in the chain from flower to food.

Subject of Research: Science

Article Title: Climate change will lead to local extinctions and mismatched range contractions disrupting bee-dependent crop pollination

Article References: Oliveira, W., Cruz-Neto, O., Silva, J. L. S., Tabarelli, M., Peres, C. A., & Lopes, A. V. (2025). Climate change will lead to local extinctions and mismatched range contractions disrupting bee-dependent crop pollination. Frontiers in Bee Science, 3, Article 1510451. https://doi.org/10.3389/frbee.2025.1510451

Image Credits: AI Generated

DOI: 10.3389/frbee.2025.1510451

Keywords: climate change, pollinators, bees, food security, species distribution modeling, Brazil, pollination, biodiversity, Climate, change, will, lead

Environmental DNA, or eDNA, metabarcoding has transformed biodiversity monitoring over the past decade. Instead of catching and killing insects to identify them, scientists can now collect traces of genetic material that organisms shed in their environment and identify the species from those fragments. In pollinator research, the pioneering work of Thomsen and Sigsgaard in 2019 showed that flowers themselves can serve as a source of arthropod eDNA, allowing researchers to reconstruct pollination networks non-invasively. Since then, a growing number of studies have confirmed that eDNA collected from flowers can effectively reveal insect-plant interactions with high sensitivity, taxonomic breadth, and temporal resolution.

However, the method has faced persistent technical obstacles. One major problem is that flowers are not only visited by pollinators; they are also home to small insects such as thrips, aphids, and pollen beetles that may live on the flower and enter the sample as whole individuals. These flower-living organisms contribute orders of magnitude more DNA than the trace material left by transient pollinators. Because the polymerase chain reaction, or PCR, preferentially amplifies the most abundant DNA in a sample, the genetic signal of bees can be outcompeted by the overwhelming DNA of these abundant residents, producing false negatives. A second challenge lies in the universal arthropod primers themselves, which exhibit well-documented amplification bias toward certain taxonomic groups and often underrepresent bees in mixed floral community samples.

These biases are especially problematic for studies aiming to reconstruct plant-pollinator networks, because such inference requires extensive within-group taxonomic coverage rather than a focus on the most common arthropod taxa in general. The role of certain bee species may be underestimated, skewing network structure and leading to misleading conclusions for biodiversity assessments and conservation efforts. Despite bees being one of the most ecologically and economically important groups in pollination networks, no bee-specific metabarcoding primer had been available until now.

To close this gap, the research team targeted the mitochondrial cytochrome c oxidase subunit I gene, or COI, the most widely used DNA barcode for the animal kingdom. COI combines conserved primer-binding sites with sufficient sequence variation to discriminate between species, and it is well represented in public sequence databases such as BOLD and NCBI. BOLD currently contains approximately 112,000 publicly available bee sequences, of which roughly 108,000 correspond to the standard COI barcode region. The researchers downloaded COI sequences from flower-visiting arthropod families previously detected in flower wash samples, aligned them, and removed low-quality or suspect records, yielding a reference set representing 173,830 unique arthropod species, of which 2,394 were bees covering 39 percent of Austrian bee diversity.

From this alignment, the team identified conserved regions unique within bees, paying particular attention to avoiding shared consensus with non-target groups such as thrips and pollen beetles, which had previously dominated PCR output from flower wash samples. Using manual expert judgment alongside established primer design principles, they generated two forward and three reverse primer candidates with lengths of 20 to 30 base pairs, melting temperatures of 50 to 60 degrees Celsius, and expected amplicon sizes of roughly 200 to 400 base pairs. Degenerate bases were incorporated to account for sequence variation among bee taxa, and all candidates were checked for secondary structures such as hairpins and dimers. The selected pair, BeePrimeF and BeePrimeR, amplifies a short COI fragment of 198 base pairs, a length suitable for species-level resolution in most organismal groups and compatible with Illumina sequencing platforms.

Validation proceeded in two stages. In silico, the primers were screened against an alignment of 67,352 centroid sequences clustered from a total of 316,254 sequences retrieved from NCBI, using the R package PrimerMiner to calculate weighted penalty scores that account for mismatch position and type. Both primers showed high binding complementarity to bee sequences, while their affinity to non-target arthropod groups was substantially lower, with mismatches concentrated at the critical 3-prime ends where they strongly reduce amplification efficiency. In vitro, the primers were tested against DNA extracts from 48 bee specimens representing 38 species and 23 genera spanning all six bee families of Central Europe, alongside 34 non-target extracts including spiders, thrips, beetles, flies, bugs, butterflies, wasps, and ants. Thirty-three of the 38 bee extracts were successfully amplified, an 86.84 percent success rate, while only nine of the 34 non-target extracts yielded positive results, indicating a non-target exclusion rate of approximately 73.52 percent. Notably, no amplification occurred in groups known to be problematic in flower metabarcoding, such as thrips, pollen beetles, or aphids.

The decisive test came with field samples. The researchers applied BeePrime to eDNA extracted from 48 flower-wash samples collected in Austrian flower strips in 2024 and compared the results directly with the universal arthropod primer pair fwhF2/fwhR2n, one of the most widely recognized primers available. BeePrime detected bee DNA in 35 of the 48 samples, compared with only 17 for the universal primer, raising per-sample detection from 35.4 percent to 72.9 percent. At the species level, the universal primer identified 14 bee-positive samples, while BeePrime detected 87, a sixfold increase. Individual floral samples typically yielded multiple bee species rather than single detections, with a mean of 1.8 species-level detections per sample and a maximum of 6. Across the entire dataset, the universal primer recovered just six distinct bee species, whereas BeePrime detected 27.

The improvement in sequencing efficiency was equally striking. Amplifications with the universal primer produced only very low proportions of bee reads, with a median of 0.03 percent, in many cases approaching zero. BeePrime yielded a median of 15 percent and a mean of approximately 30 percent bee reads per sample, a difference confirmed as highly significant by a Wilcoxon rank-sum test. Thrips, which dominated the genus-level dataset with almost 85 percent of all reads under the universal primer, were reduced to roughly 30 percent under BeePrime, while wild bees rose from only a few percent to nearly 50 percent of reads. Together with honeybees, bees represented more than 60 percent of the total relative read proportion with the new primer pair.

Every bee taxon detected with BeePrime had previously been recorded at the same sites using traditional hand-net sampling and morphological identification, corroborating the molecular assignments. The authors caution, however, that empirical performance has so far been demonstrated only for common bee taxa in Central European agricultural landscapes, and that local testing is advised before applying the primer pair in other biogeographic regions. Several Apidae species, including some carpenter bees and long-horned bees, did not amplify successfully despite acceptable primer fit, so underdetected lineages should not automatically be interpreted as absent in ecological network analyses. The researchers also emphasize that read numbers do not translate directly into bee abundance, since DNA deposition depends on body size, body hairiness, and behavior. Nevertheless, by overcoming a key methodological bottleneck in pollinator eDNA metabarcoding, BeePrime substantially strengthens the molecular toolkit available for monitoring bee diversity and resolving plant-pollinator networks, marking a major step toward establishing floral eDNA as a routine approach in ecological monitoring and conservation.

Subject of Research: Development and validation of a bee-specific COI metabarcoding primer pair for non-invasive monitoring of plant-pollinator interactions

Article Title: A bee-specific metabarcoding primer pair for non-invasive assessments of plant–pollinator interactions

Article References: Gurten, S., Sint, D., Traugott, M., & Rennstam Rubbmark, O. R. (2026). A bee-specific metabarcoding primer pair for non-invasive assessments of plant–pollinator interactions. Metabarcoding and Metagenomics, 10, Article e183708. https://doi.org/10.3897/mbmg.10.183708

Image Credits: AI Generated

DOI: 10.3897/mbmg.10.183708

Keywords: bees, environmental DNA, metabarcoding, pollinators, primer design, COI barcode, plant-pollinator networks, biodiversity monitoring, bee-specific, primer, pair, non-invasive

The threats are layered and interacting. Global warming imposes thermal stress on social and solitary bees alike, while habitat loss and introduced parasites compound the damage. Honey bees, Apis mellifera, the world’s most economically important pollinator, are particularly vulnerable to a suite of pressures, most notably the parasitic mite Varroa destructor and the viruses it carries and spreads. The eleven studies span climate impacts, parasite dynamics, bee genetics, hive microbiota, and ways to improve pollination efficiency as an agricultural service, and the editorial’s authors argue that only by examining these threads together can researchers support the well-being of bees worldwide.

Climate-induced heat stress is a growing threat to bee diversity, and solitary bees appear especially vulnerable because they cannot thermoregulate their nests. Vilchez-Russell and Rafferty’s contribution shows that heat stress reduces survival and adult emergence rates in solitary bees and alters body size, development time, sex ratios, and diapause, the dormant state many insects rely on to time their life cycles. Rising temperatures can also break the synchrony between bee emergence and floral resource availability, meaning bees may wake from diapause to find the flowers they depend on already gone. The editorial calls for habitat management that provides thermal refugia and integrated conservation planning that accounts for climate variability and species-specific resilience mechanisms.

Acosta and colleagues propose a methodological framework to identify priority zones for monitoring wild bee responses to climate change, using the Brazilian stingless bee Melipona fasciculata as a case study. Their approach classifies habitat into three types: Loss zones, which will become unsuitable for the species; Gain zones, which will become suitable; and Persistent zones, which remain suitable and are therefore best for long-term monitoring. By achieving better spatial precision for conservation measures, the framework offers conservationists a practical tool for deciding where to invest limited monitoring resources as climates shift.

Urban heat adds another dimension. The Urban Heat Island Effect refers to elevated temperatures in cities caused by human infrastructure such as buildings and roads, and it disproportionately affects ectothermic organisms such as bees. Polidori and colleagues note that temperature increases generally affect bee physiology, reduce foraging efficiency and reproductive success, and that specialists and thermosensitive species risk local extinction. Urban heat can also shift flowering times and resource availability, creating mismatches between bees and the plants they pollinate. The editorial argues that more comprehensive, multi-scalar research combining urban ecology, thermal biology, and pollination science is needed to inform urban biodiversity planning.

Bumble bee populations are declining globally, with climate warming identified as a key driver. Kevan and colleagues highlight a striking biological constraint: bumble bee colonies maintain a remarkably consistent brood rearing temperature across species and biogeographic regions, suggesting limited evolutionary plasticity. Bumble bees are more susceptible to heat stress than to cold, and while nest placement and structure significantly affect nest temperatures, few data exist on thermal gradients and insulation properties inside bumble bee nests. Understanding how bumble bee physiology, ecology, and nest architecture shape responses to climate change is therefore a research priority.

For honey bees, the devastating interplay of bees, Varroa mites, and viruses is a major cause of colony losses worldwide. Common beekeeping practices, such as splitting colonies and transporting hives, inadvertently facilitate virus and mite dispersal. Miticides help control mites but do not eliminate circulating viruses, and mite resistance to acaricides is a growing problem. Morfin and colleagues show that Varroa infestation reduces honey bee lifespan and exacerbates viral infections by suppressing bee immune responses and increasing virus titers, and unmanaged infestations can lead to colony collapse. The editorial stresses that effective bee health management requires tackling the synergistic threat posed by mites and viruses together rather than separately.

Resistance traits such as Varroa Sensitive Hygiene, in which worker bees detect and remove infested brood, hold potential for selective breeding programs aimed at mite resistance. Lester’s contribution examines how overuse and reliance on acaricides have driven the evolution of resistance in Varroa populations, and proposes strategies including rotating acaricides with different modes of action, applying treatments only when infestation thresholds are exceeded, and improving monitoring of resistance alleles. Beekeepers, researchers, and regulators are encouraged to work collaboratively to preserve the efficacy of current treatments while integrative approaches combining genomics, ecology, and behavior are developed into multifaceted solutions.

Advances in bee biology are also reshaping crop pollination. Owen’s study of chromosome diversity across the bee superfamily Apoidea reveals a wide range of haploid chromosome numbers, from three to twenty-eight, but a lack of data for many species makes it difficult to determine relationships and evolutionary pathways. Improved methods for preserving and analyzing chromosomes, including C-banding and FISH techniques, are advancing understanding of chromosomal rearrangement, and modern genomic tools can now explore the adaptive significance of chromosomal variation. Anderson and Copeland’s meta-analysis of 35 studies of honey bee hive microbiota found a distinct and relatively stable hive microbiome dominated by aerobic or aerotolerant bacteria, shared across larval, worker and queen mouthparts, worker crops and hypopharyngeal glands, queen crops and midguts, beebread, royal jelly, and honey. This microbiota contributes to the preservation of stored pollen and honey, inhibition of pathogens, and colony-level disease resistance, and the editorial argues it should be considered in colony health diagnostics.

Honey bees can also be trained. Farina and colleagues showed that bees can associate floral scents with food rewards, and once trained, they visit target crops more frequently, potentially enhancing pollination precision. Continued improvement of automated within-hive conditioning could make honey bees more effective agents of pollination services, though additional research is needed to determine viability for specific crops. On the conservation front, Oddie and Dahle and related work suggest that conflicts between beekeepers and conservationists over competition between wild and managed pollinators can give way to common ground: honey bees and wild pollinators face shared threats, beekeepers can serve as early detectors of environmental stressors, and superior fruit set and quality are obtained when wild and managed bees visit the same flowers, showing additive or synergistic effects. The editorial concludes that a coordinated international effort, incorporating changes in management practices, is needed to address the adverse conditions currently confronting bees, and that the next challenge is prioritizing and implementing the improvements these studies identify.

Subject of Research: Biology

Article Title: Editorial: Horizons in bee science

Article References: De Jong, D., Kevan, P. G., Imperatriz-Fonseca, V. L., Lester, P. J., Fahrbach, S. E., & Mayfield, M. M. (2025). Editorial: Horizons in bee science. Frontiers in Bee Science, 3, Article 1667590. https://doi.org/10.3389/frbee.2025.1667590

Image Credits: AI Generated

DOI: 10.3389/frbee.2025.1667590

Keywords: bees, pollination, climate change, Varroa destructor, honey bee, bumble bee, bee health, microbiome, Editorial, Horizons, science, scientific research