Apis Mellifera Research Articles

1117. Crepidiastrum grandicollum (Koidz.) Nakai: Compositae: Plants in peril 41

SummaryCrepidiastrum grandicollum (Koidz.) Nakai (Compositae: Lactuceae: Crepidinae) is described and illustrated. The current synonymy is provided, together with type citations for each of the names and statements of the type material. A selection of verified illustrations of the species in the literature is provided. Statements of the species' distribution, habitat and ecological preferences (with observations on the phytosociological classification), phenology, conservation status, and the etymology of both generic and specific epithets are given along with vernacular names, some of which are apparently literal translations of the Latin binomial. Cultivation, propagation, and availability notes are provided, although the species is Critically Endangered and currently only cultivated Koishikawa Botanical Garden, University of Tokyo, Japan, as part of the Ministry of the Environment's Rare Wild Fauna and Flora Species Protection and Breeding Project. Discussions include pollination syndromes in Crepidiastrum in the Bonin Islands, the intricacies of the involvement of the Honey Bee in their pollination (compared with conservation measures) and the displacement of native insect pollinators, mention of seed/achene dispersal and evolution within the genus, conservation proposals, including the use of exclosures to prevent destruction by feral goats (Capra hircus), and electric fences, adhesive traps and Teflon™ sheets to help control the lizard known as the Green Anole (Anolis carolinensis); typhoon damage and the potential for issues with ants ‐ Pheidole (Westwood) spp. (including the African Big‐headed Ant, P. megacephala) are also mentioned. Some consideration for the rôle of Arbuscular Mycorrhizal (AM) associations with the endemics in conservation programmes should not be overlooked. Attention is drawn to observations on some bizarre web sites with somewhat bogus information on the species, and why they should be disregarded.

Stable pollinator communities in different white clover populations suggest potential win-win scenarios for crop yield and biodiversity

Compared to monocultures, intercropping systems offer many agronomic benefits, including higher yield stability. In this study, we assessed whether cropping systems that are beneficial for yield stability are also beneficial for pollinator communities and whether the effect is modulated by the landscape type. Using a replicated block design in one heterogeneous and one homogeneous agricultural landscape, we studied the pollinator communities in eight populations (i.e., genotypes) of white clover (Trifolium repens) grown as a monoculture or as a two-species mixture (together with perennial ryegrass, Lolium perenne) or three-species mixture (together with perennial ryegrass and chicory, Cichorium intybus). We recorded 1486 honey bees and 1254 wild pollinators belonging to 46 species. Bumble bees were the most abundant wild pollinators (49.6 %), followed by hover flies (23.4 %), and non-Bombus wild bees (21.5 %). Lepidoptera accounted for only 5.4 % of the wild pollinators. We found a higher species richness and abundance of wild pollinators in monocultures than in two-species mixtures, but white clover population did not influence pollinators. Moreover, species richness and abundance were also higher in the homogeneous landscape than in the heterogenous one. Most species were foraging on white clover. However, 18 species (39.1 %, n = 18/46) were recorded foraging on chicory and/or weeds, and ten of these wild pollinator species were never recorded on white clover. Our study highlights that diverse pollinator communities require both abundant floral resources and diverse plant communities, that their needs are not in conflict with the goal of achieving yield stability, and that the landscape type can modulate the effect of the cropping system. Moreover, the lack of pollinator preference for different white clover populations suggests that farmers can select mixtures that enhance yield stability without negatively affecting pollinator communities. Overall, these results highlight that intercropping systems comprising several plant species and plant genotypes can guarantee yield stability without compromising the pollinator community, showing that win-win situations for farmers and biodiversity are possible.

Routing algorithm for sparse unstructured P2P networks using honey bee behavior

SummaryUnstructured peer‐to‐peer (P2P) networks pose unique challenges for efficient and scalable routing. In this study, we introduce a novel routing algorithm inspired by the foraging behavior of honey bees named Honey Bee Optimization in P2P Networks (HBO_P2P) to address the inherent limitations of routing in unstructured P2P networks, focusing on improving packet delivery, minimizing hop count, reducing message overhead, and optimizing overall throughput. To evaluate the performance of our proposed algorithm, we conducted comprehensive experiments comparing it with existing algorithms commonly used in P2P networks, namely, particle swarm optimization (PSO), genetic algorithm (GA), and ant colony optimization (ACO). After the simulation, we got the results as follows: Our algorithm outperforms ACO, GA, and PSO by exhibiting the highest number of data hops indicating potential efficiency in route optimization. Routing overhead is also minimal as compared to ACO, GA, and PSO. The average data packet delay is also low in our algorithm as compared to ACO, GA, and PSO. HBO_P2P achieves the highest throughput, nearly reaching 100 Mbps. While ACO and GA exhibit similar throughput of around 80 Mbps, and PSO has the lowest throughput, approximately 60 Mbps.

Elevated atmospheric CO2 alters the multi-element stoichiometry of pollen-bearing oak flowers, with possible negative effects on bees

Increasing atmospheric CO2 levels change the elemental composition in plants, altering their nutritional quality and affecting consumers and ecosystems. Ecological stoichiometry provides a framework for investigating how CO2-driven nutrient dilution in pollen affects bees by linking changes in pollen chemical element proportions to the nutritional needs of bees. We investigated the consequences of five years of Free Air CO2 Enrichment (FACE) in a mature oak-dominated temperate forest on the elemental composition of English oak (Quercus robur) pollen. We measured the concentrations and proportions of 12 elements (C, N, P, S, K, Na, Ca, Mg, Cu, Zn, Fe, and Mn) in Q. robur pollen-bearing flowers collected from the Birmingham Institute for Forest Research (BIFoR) FACE facility. An elevated CO2 (eCO2) level of 150 ppm above ambient significantly reduced the S, K, and Fe levels and altered the multi-element ratio, with different elements behaving differently. This shift in pollen multi-element composition may have subsequent cascading effects on higher trophic levels. To assess the impact on bees, we calculated the stoichiometric mismatch (a measure of the discrepancy between consumer needs and food quality) for two bee species, Osmia bicornis (red mason bee) and Apis mellifera (honey bee), that consume oak pollen in nature. We observed stoichiometric mismatches for P and S, in pollen under eCO2, which could negatively affect bees. We highlight the need for a comprehensive understanding of the changes in pollen multi-element stoichiometry under eCO2, which leads to nutrient limitations under climate change with consequences for bees.

Synergistic effects between microplastics and glyphosate on honey bee larvae

Microplastic (MPs) pollution has emerged as a global ecological concern, however, the impact of MPs exposure, particularly in conjunction with other pollutants such as glyphosate (GLY) on honey bee remains unknown. This study investigated the effects of exposure to different concentrations of MPs and their combination with GLY on honey bee larvae development, or during the larvae period, regulation of major detoxification, antioxidant and immune genes, and oxidative stress biomarkers. Results revealed that combined exposure to MPs and GLY decreased larvae survivorship and weight, while exposure to MPs alone showed no significant differences. Both MPs and GLY alone downregulated the defensin-1 gene, but only combined exposure with GLY downregulated the hymenoptaecin gene and increased catalase enzyme activity. The data suggest a synergistic effect of MPs and GLY, leading to immunosuppression and reduced larvae survival and weight. These findings highlight potential risks of two prevalent environmental pollutants on honey bee health.

Effect of Flowering Period on Drone Reproductive Parameters (Apis mellifera L.).

Insufficient protein intake during the larval phase of drones affects the development of reproductive organs and spermatogenesis. The aim of the study was to evaluate the effect of the flowering-scarcity and flowering-onset periods on the eversion of the copulatory apparatus, ejaculation, and sperm quality of drones (Apis mellifera L.). To stimulate the laying of drone eggs during the flowering-scarcity period, 1 L of sugar syrup was supplied weekly to the hives, along with a protein supplement made of 20% pollen and 80% brewer's yeast. During the periods of flowering scarcity and the onset of flowering, 800 drones were collected (200 per month). At the onset of flowering, 270 drones showed eversion of the copulatory apparatus, of which 162 ejaculated, compared to the flowering-scarcity period, where 112 drones showed eversion of the copulatory apparatus and 39 drones ejaculated. During the period of flowering onset, sperm parameters such as volume, concentration, motility, viability, acrosome integrity, and mitochondrial activity were higher compared to the period of flowering scarcity. In conclusion, we observed a greater number of drones with eversion of the copulatory apparatus and ejaculation, as well as better sperm quality with the drones bred during the period of flowering onset. These differences indicate that the flowering-scarcity period significantly impacts the reproductive parameters of drones.

Chalkbrood Disease Caused by Ascosphaera apis in Honey Bees (Apis mellifera)-Morphological and Histological Changes in Infected Larvae.

Chalkbrood is a mycological brood disease of the Western honey bee (Apis mellifera), caused by the fungus Ascosphaera apis. The aim of this study was the investigation of the pathology of artificially reared Apis mellifera larvae, experimentally infected with A. apis spores (1.0 × 103 spores/larva). Non-infected larvae served as control. Five living larvae and every dead larva were collected daily (day 1-7 p.i.). All larvae were macroscopically measured, photographed, formalin-fixed, and histologically processed (hematoxylin-eosin stain, Grocott silvering). Histological sections were digitized, and the size of the larvae was measured (mouth-after length, area) and statistically analyzed. Twenty-six larvae from the collected larvae (n = 64; 23 dead, 3 alive) showed histological signs of infection from 3 d p.i. onwards. The dead larvae showed macroscopically white/brown deposits, indistinct segmentation, and a lack of body elongation. Infected larvae were significantly smaller than the controls on days 3 p.i. (p < 0.05), 4 p.i. (p < 0.001), and 6 p.i. (p < 0.05). The early time of death, the low number of transitional stages, and the strong penetration of the larval carcass with fungal mycelium indicate a rapid and fulminant infection process, which is probably relevant for spreading the disease within the colony.

Detection of Entomological Origin of Honey Sold in Indonesia Based on &lt;i&gt;16S rRNA&lt;/i&gt; Gene Analysis

Honey is known for its various benefits for health, cosmetic ingredients, and other industrial materials. Especially, during the Covid-19 pandemic, many people consume honey to maintain body endurance. In Indonesia, the honey produced is dominated by Apis mellifera honey. With a cheaper price and a larger quantity, A. mellifera honey is often offered as forest honey or stingless bee honey to get more profit. Therefore, this study aims to determine the entomological origin of honey claimed as forest honey and stingless bee honey sold in the Indonesian market using the detection of 16S rRNA gene amplicon. This study tested 30 samples of forest honey and 30 samples of stingless bee honey. DNA that has been isolated from honey samples was amplified by PCR using 16S rRNA primers. The results from the sequence analysis showed that nine of honey samples were identified as honey fraud. Two samples were confirmed as falsification of the origin of honey-producing bees and four honey samples were confirmed as honey mislabelling. From this study it can be concluded that, it is possible to determine the entomological origin of honey molecularly by sequencing the 16S rRNA gene. Therefore, this method can be used to identify honey fraud that may occur on the market.

The Status of Beekeeping in Simada District, Amhara, Ethiopia, with Its Challenges and Opportunities

The study was designed to assess the existing beekeeping practices, constraints, and potential of honeybee production in Simada district. The study was carried out in four proportionally selected kebeles of highland, midland, and lowland agro-ecology. Accordingly, a total sample size of 146 beekeepers, depending on their potential, was interviewed using a structured and semi-structured questionnaire. A semi-structured questionnaire, field observation, and focal group discussion were employed to collect primary data. Descriptive statistics such as mean, frequency, and standard deviation were used to analyze the data. The majority of beekeepers in the district are mail-headed, and the majority can read and write. Beekeepers practiced three hive types but mostly used traditional hives. The majority of honeybee colonies are found in midland agro-ecology, but they are not significantly different (P&amp;lt;0.05). About 57.5% of beekeepers obtain their colony through buying, and their colony increases through reproductive swarming. Beekeepers construct both traditional and top-bar hives from the surrounding available material. Frame hives were obtained from GOs on a credit basis. Beekeepers indicated that the majority of honey was harvested in October and November. The second minor harvesting period was from May to June, which depends on the nature of the yearly rainfall conditions. As the respondent&amp;apos;s described, they stored honey below one year in a plastic jar, clay jar, and plastic sack when plenty of products were obtained and for medicinal value, unless they used honey during harvesting as a source of income. Predators and pests are major constraints on honey bee production, followed by pesticides and herbicides in the study area. Other identified beekeeping constraints were shown in relative order of importance: drought, death of colony, lack of water, migration, and disease are some of the problems that hinder productivity. Honeybees required feed supplementation during the dry season; about 28% of beekeepers fed their colonies with higher supplements made from February to April. The commonly used supplements were peas and bean flour (Shiro), barley flour (Besso), sugar, honey, and others, including Niger.

Analysis of fast calcium dynamics of honey bee olfactory coding

Odour processing exhibits multiple parallels between vertebrate and invertebrate olfactory systems. Insects, in particular, have emerged as relevant models for olfactory studies because of the tractability of their olfactory circuits. Here, we used fast calcium imaging to track the activity of projection neurons in the honey bee antennal lobe (AL) during olfactory stimulation at high temporal resolution. We observed a heterogeneity of response profiles and an abundance of inhibitory activities, resulting in various response latencies and stimulus-specific post-odour neural signatures. Recorded calcium signals were fed to a mushroom body (MB) model constructed implementing the fundamental features of connectivity between olfactory projection neurons, Kenyon cells (KC), and MB output neurons (MBON). The model accounts for the increase of odorant discrimination in the MB compared to the AL and reveals the recruitment of two distinct KC populations that represent odorants and their aftersmell as two separate but temporally coherent neural objects. Finally, we showed that the learning-induced modulation of KC-to-MBON synapses can explain both the variations in associative learning scores across different conditioning protocols used in bees and the bees' response latency. Thus, it provides a simple explanation of how the time contingency between the stimulus and the reward can be encoded without the need for time tracking. This study broadens our understanding of olfactory coding and learning in honey bees. It demonstrates that a model based on simple MB connectivity rules and fed with real physiological data can explain fundamental aspects of odour processing and associative learning.

Seasonal variation and characterisation of pollen collected by honeybee Apis mellifera scutellata Lepeletier in southwest Ethiopia

The ability of honeybees to successfully grow, reproduce and build strong colonies and produce honey depends on their ability to obtain enough resources from flowering plants within appropriate seasons. However, little is known about seasonal variations and characterisation of honeybee pollen collected in Ethiopia. Therefore, to address this, a total of 2160 pollen samples were collected from five districts in different seasons for two years. The pollen samples were acetolysed and taxonomically identified. The pollen type was classified into frequency categories based on its relative abundance. Diversity indices and species richness were also calculated and compared between districts and seasons. The highest species richness was recorded in Guraferda district, while the lowest was recorded in Godare district. The spring season was considered the most suitable as it has the highest richness in all districts. The ‘predominant’ and ‘secondary’ pollen sources were identified from different plant genera in Asteraceae (62.23%), Mimosaceae (23.59%), Myrtaceae (43.76%), Poaceae (27.25%), Rubiaceae (36.64%), Combretaceae (28.14%), Euphorbiaceae (18.97%), Burseraceae (16.35%), Convolvulaceae (16.52%), Solanaceae (21.40%), Icacinaceae (17.86%), and Dichapetalaceae (16.35%). Terminalia spp. (Combretaceae) had the highest pollen counts and are common in the area. Other species with significant pollen counts included Acacia spp. (Mimosaceae), Croton macrostachyus (Euphorbiaceae), Eucalyptus camaldulensis (Myrtaceae), Vernonia spp. (Asteraceae) and Iodes spp. (Icacinaceae). This study indicated that southwest Ethiopia has great potential for honey production and beekeeping business based on the study of pollen collected. Thus, these results help as a guide to the optimal use of flora resources by a honeybee in the areas.

Distribution of honey bee mitochondrial DNA haplotypes in an Italian region where a legislative act is protecting the Apis mellifera ligustica subspecies

The conservation of the genetic integrity of Apis mellifera subspecies has emerged as an important objective. In 2019, the Emilia-Romagna region became the first Italian regional authority to issue a law specifically addressing the protection of the native Apis mellifera ligustica subspecies. In this study we analysed a highly informative portion of the mitochondrial DNA (mtDNA), widely used for assessing genetic diversity of honey bee populations. By analysing 1143 honey bees sampled after the introduction of this law, we provided a snapshot of the distribution of mtDNA haplotypes in this region. The two most frequent mtDNA haplotypes were C1 (characteristic of A. m. ligustica) and C2 (characteristic of A. m. carnica), reported in 86.5% and 11.0% of the analysed bees, respectively. About 1.3% and 1.1% of the analysed bees carried mtDNA haplotypes of the A and M lineages (haplotypes A1a, A1e, A4, A26, A65 and two novel ones, A2w and A6a; M3, M3a, M4 and M79). Continued genetic monitoring will be important to assess the impact of this regional law over the coming years. Based on the obtained results, we recommend a more stringent policy to prevent the erosion of the genetic integrity of the native subspecies A. m. ligustica.

Study of Eucalyptus pauciflora L. characteristics from Algeria and its impact on the mite affecting honeybees Apis mellifera

Essential oils play a crucial role in biological control against parasites threatening the beekeeping stock, both in Algeria and globally. Their appropriate use helps reduce the adverse effects of chemical products on human health and the environment. The purpose of this study is to analyze the components of Eucalyptus pauciflora essential oil grown in Algeria and to evaluate its impact on the marine shrimp Artemia salina and the mite Varroa destructor, while also comparing it to other species of Eucalyptus from the same region namely, Eucalyptus robusta, globulus, sideroxylon, and amygdalina, which have been examine in previous research. Steam distillation of fresh leaves from Eucalyptus pauciflora yielded 0.73% essential oils. This plant contains a total of thirty-nine chemical compounds, among which the most significant are 1,8-cineole (57.45%), β-cymene (5.44%), spathulenol (5.38%), trans-verbenol (4.31%), and α-pinene (3.11%). A lethality test on brine shrimp (BSL) revealed that Eucalyptus pauciflora exhibits toxicity with a median lethal concentration (LC50) of 53.51 ppm. Field trials conducted on hives infested with Varroa destructor showed that the acaricidal effect of Eucalyptus pauciflora is superior to that of amygdalina and sideroxylon species, but inferior to that of globulus and robusta species, all sourced from the same herbarium (Draa Naga) in northeastern Algeria. The results of this research highlight the benefits of Eucalyptus essential oils to be integrated into the formulation of natural acaricides that are environmentally friendly to combat Varroa destructor infestation.

Estimating genus-specific effects of non-native honey bees and urbanization on wild bee communities: A case study in Maryland, United States

Non-native species have the potential to detrimentally affect native species through resource competition, disease transmission, and other forms of antagonism. The western honey bee (Apis mellifera) is one such species that has been widely introduced beyond its native range for hundreds of years. There are strong concerns in the United States, and other countries, about the strain that high-density, managed honey bee populations could pose to already imperiled wild bee communities. While there is some experimental evidence of honey bees competing with wild bees for resources, few studies have connected landscape-scale honey bee apiary density with down-stream consequences for wild bee communities. Here, using a dataset from Maryland, US and joint species distribution models, we provide the largest scale, most phylogenetically resolved assessment of non-native honey bee density effects on wild bee abundance to date. As beekeeping in Maryland primarily consists of urban beekeeping, we also assessed the relative impact of developed land on wild bee communities. Six of the 33 wild bee genera we assessed showed a high probability (> 90 %) of a negative association with apiary density and/or developed land. These bees were primarily late-season, specialist genera (several long-horned genera represented) or small, ground nesting, season-long foragers (including several sweat bee genera). Conversely, developed land was associated with an increase in relative abundance for some genera including invasive Anthidium and other urban garden-associated genera. We discuss several avenues to ameliorate potentially detrimental effects of beekeeping and urbanization on the most imperiled wild bee groups. We additionally offer methodological insights based on sampling efficiency of different methods (hand netting, pan trapping, vane trapping), highlighting large variation in effect sizes across genera. The magnitude of sampling effect was very high, relative to the observed ecological effects, demonstrating the importance of integrated sampling, particularly for multi-species or community level assessments.

Assessment of oxidative status, detoxification capacity and immune responsiveness in honey bees with ageing

The honey bee (Apis mellifera L.), as an eusocial insect species, is an important model organism in research focusing on ageing and longevity, due to prominent seasonal lifespan plasticity within the worker caste (summer and winter worker bees). In this study, we employed a screening approach to evaluate several molecular parameters, providing comprehensive insights into the antioxidative (superoxide dismutase and catalase activity, reduced glutathione and sulfhydryl group content, total antioxidative capacity), detoxifying (glutathione S-transferase and acetylcholinesterase activity), and immune (phenol oxidase and glucose oxidase activity) status, as well as vitellogenin content, in the summer and winter generation of honey bees, across ageing stages and in two body compartments: the whole abdomen and the head. Summer worker bees were collected weekly for six weeks, while winter bees were collected monthly for five months. The results of our study clearly indicate a reduced overall antioxidative capacity of older groups of worker bees from both generations, while the parameters of immune responsiveness mostly contributed to the separation between the two generations based on season rather than age categories. Detoxification ability appeared to be more susceptible to environmental factors. An age-dependent increase in vitellogenin content was recorded in the abdomen, but without seasonal differences. These findings provide an excellent starting point for further investigations into age-related changes, particularly within the context of honey bee sociality.

The Cytotoxic Effects of Turkish Bee Venom (Apis mellifera) on Selected Cancer Cell Lines

The Cytotoxic Effects of Turkish Bee Venom (Apis mellifera) on Selected Cancer Cell Lines

Investigation of apoptotic efficacy of propolis in MCF-7 cell line

Objective: Propolis, also known as bee glue, is a resinous compound collected by honey bees from various plants and processed by their saliva enzymes. Propolis and its components have been studied for their cytotoxic effects on cell lines in vitro, and recent studies have shown that they also have an antitumor effect in vivo. This study aimed to investigate the in-vitro apoptotic effects of propolis on the human breast cancer cell line (MCF-7). Method: The MTT test was used to determine the effect of propolis on cell viability and the doses to be administered. The GraphPad Prism Version 6.01 program was used to analyze the MTT results, while the qRT-PCR method was used to determine the expression levels of Caspase-8, Caspase-9, and Bcl-2 genes. The RT2 profiler PCR Assay Data Analysis version 3.5 was used to analyze gene expression data. Results: This study it was found that doses of 3.9 and 7.8 µg/ml of propolis showed no cytotoxic effect, while doses of 15.625 µg/ml and above had a cytotoxic effect. There was no change in the expression levels of genes at concentrations of 3.9 µg/ml and 7.8 µg/ml of propolis. However, at 15.625 µg/ml of propolis, Caspase-9 gene expression increased 11.89-fold (p=0.033). Although there was no significant difference in Caspase-8 gene expression in the extrinsic pathway of apoptosis (p=0.437), a 0.04-fold decrease in anti-apoptotic Bcl-2 gene expression was observed (p=0.000098). Conclusion: In conclusion, propolis showed a dose-dependent cytotoxic effect on the MCF-7 cell line, induced apoptosis, and did so via the intrinsic pathway of apoptosis. The study suggests that propolis has high potential as an anticancer agent since its apoptotic effects have been demonstrated in the MCF-7 cell line.

Colonies under dysbiosis benefit from oxalic acid application: the role of landscape and beekeeping practices in microbiota response to treatment

AbstractThe Varroa destructor mite causes severe losses of Apis mellifera colonies, requiring recurring treatments. One such treatment is oxalic acid (OA), considered ecological. However, it is unclear whether OA affects the honey bee gut microbiota or other hive-associated microbiotas. Herein, we studied the effect of three OA treatments (trickling at 2.1% or 4.2%, and sublimation through Varrox®) upon microbial communities associated with workers’ gut, hive bee bread and pupae, sampled from conventionally or ecologically managed colonies under different anthropization levels (located in urban, rural or mountainous landscapes). We hypothesized that treatment with OA would impact the diversity and composition of bacteria and/or eukaryotic communities, and that the effect would be dose-dependent and specific to the beehive niche. Results showed that the microbiomes of apiaries under different anthropization levels and management strategies differed prior to OA application. Neither the bacterial nor the fungal communities of bee bread and pupae shifted due to OA treatment. Independent of the dosage and the application method (trickling or sublimation), OA induced slight compositional changes in the bacterial profiles of honeybee guts. Those changes were stronger the higher the anthropization (in colonies from urban areas under conventional management). OA treatment reduced the relative abundance of several pathogens, such as Nosema ceranae, and decreased the overall bacterial diversity down to values found in less anthropized colonies. Thus, our results suggest that, aside from managing Varroa infestations, OA could have beneficial effects for stressed colonies while not impairing honey bee resilience from a microbial point of view.

Phytochemical profiles of honey bees (Apis mellifera) and their larvae differ from the composition of their pollen diet.

Pollen and nectar consumed by honey bees contain plant secondary metabolites (PSMs) with vital roles in plant-insect interactions. While PSMs can be toxic to bees, they can also be health-promoting, e.g. by improving pesticide and pathogen tolerances. As xenobiotics, PSMs undergo post-ingestion chemical modifications that can affect their bioactivity and transmission to the brood. Despite the importance of understanding honey bee PSM metabolism and distribution for elucidating bioactivity mechanisms, these aspects remain largely unexplored. In this study, we used HPLC-MS/MS to profile 47 pollen PSMs in honey bees and larvae. Both adult bees and larvae had distinct PSM profiles that differed from their diet. This is likely due to post-ingestion metabolism and compound-dependent variations in PSM transmission to the brood via nurse bee jelly. Phenolic acids and flavonoid aglycones were most abundant in bees and larvae, whereas alkaloids, cyanogenic glycosides and diterpenoids had the lowest abundance despite being consumed in higher concentrations. This study documents larval exposure to a variety of PSMs for the first time, with concentrations increasing from early to late larval instars. Our findings provide novel insights into the post-ingestion fate of PSMs in honey bees, providing a foundation for further exploration of biotransformation pathways and PSM effects on honey bee health.

Spermidine supplementation influence on protective enzymes of Apis mellifera (Hymenoptera: Apidae).

Dietary supplementation has been proposed as a sustainable way to improve the health and resilience of honey bees (Apis mellifera, L.), as the decline in their numbers in recent decades has raised scientific, environmental, and economic concerns. Spermidine, a natural polyamine, has been shown to be a promising substance for honey bee supplementation, as its health-promoting effects have been demonstrated in numerous studies and in different organisms. As already shown, supplementation with spermidine at a certain concentration prolonged lifespan, reduced oxidative stress, and increased antioxidative capacity in honey bees. The aim of the present study was to investigate whether spermidine supplementation affects gene expression and/or enzyme activity of antioxidative and detoxification enzymes and immune response markers in honey bee workers. The different gene expression and enzyme activity patterns observed in abdominal and head tissues in response to spermidine supplementation suggest tissue-specific and concentration-dependent effects. In addition, the immune response markers suggest that spermidine has the ability to boost honey bee immunity. The observed changes make a valuable contribution to understanding the molecular mechanisms by which spermidine may exert its beneficial effects on the bee's health and lifespan. These results support the idea of the use of spermidine supplementation to promote bee health and resilience to environmental stressors, emphasizing that the dose must be carefully chosen to achieve a balance between the pro- and antioxidant effects of spermidine.