European Honey Bee Apis Mellifera Research Articles

Water Deprivation and Sowing Times Alter Plant-Pollination Interactions and Seed Yield in Sunflower, Helianthus annuus L. (Asteraceae).

Climate change effects, including temperature extremes and water stress, cause abiotic stress in plants. These changes directly affect flowering and the flower reward system for pollinators, influencing plant-pollinator interactions and ultimately seed production in flowering plants. Here, we tested the effects of water deprivation on the behavior of various pollinator species, plant-pollinator interactions, and the seed yield of sunflower, Helianthus annuus L. (Asteraceae). Sunflower was sown during four different months (January-April) and subjected to two different water availability levels (well-watered and water-deprived). Pollinator abundance was recorded five times a day (8:00 am, 10:00 am, 12:00 pm, 2:00 pm, and 4:00 pm) from flower heads and the florets. In addition, foraging behavior was also recorded. We found that lowest abundance, visit duration, and visitation rate occurred in April-sown sunflower. The European honey bee Apis mellifera L. (Hymenoptera: Apidae) was the most abundant visitor to sunflower, the hover fly Eristalinus aeneus (Diptera: Syrphidae) exhibited the longest visit duration, while Xylocopa sp. (Hymenoptera: Apidae) exhibited the highest visitation rate. The visitation rate of bees was significantly affected by water stress, with more bee visits occurring under well-watered conditions. Additionally, plant parameters, including flower head diameter, head weight, seed number, and seed weight, were significantly lower in the water-deprived treatments in April-sown sunflower. Open flowers without the pollination exclusion cages showed a higher yield, indicating the pollination dependence of sunflower. In conclusion, the plant modifications induced by sowing months and water-deprived conditions may alter pollinator behavior and may ultimately affect sunflower yield.

Exposure to constant artificial light alters honey bee sleep rhythms and disrupts sleep

Artificial light at night (ALAN) changes animal behavior in multiple invertebrates and vertebrates and can result in decreased fitness. However, ALAN effects have not been studied in European honey bees (Apis mellifera), an important pollinator in which foragers show strong circadian rhythmicity. Colonies can be exposed to ALAN in swarm clusters, when bees cluster outside the nest on hot days and evenings, and, in limited cases, when they build nests in the open. We captured and maintained foragers in incubated cages and subjected them to constant light (LL), constant dark (DD), or 12 h light:12 h dark (LD) cycle, and observed them with infrared cameras. After 79 h, there was a significant interaction of treatment and time because LL bees slept less. In detail, the bees maintained a regular sleep pattern for three days but LL bees showed a shift on the fourth day. LL bees had the largest sleep differences from LD controls, with trends of lengthened periods and increased phase misalignment from both LD and DD bees. LL bees also experienced significantly more disturbances from their nestmates and preferred to sleep in the lower portion of the cages, which had significantly lower light intensity. These findings suggest that ALAN can disrupt the sleep of honey bee foragers, which has implications for their behavior and overall colony health.

Exposure to organophosphate insecticides induces behavioral changes and acetylcholinesterase inhibition in Apis mellifera

European honey bee (Apis mellifera L.) is an essential pollinator that contributes significantly to the global ecosystem and agricultural productivity. However, their population has been facing unprecedented threats, primarily due to their exposure to various pesticides, including organophosphates. These pesticides are being widely used in agriculture to control insect pests due to their efficacy, but their non-selective nature raises concerns about their impact on honey bees. Insecticides viz., chlorpyriphos 20 Emulsifiable Concentrate, dimethoate 30 Emulsifiable Concentrate, and profenophos 50 Emulsifiable Concentrate at a range of 0.005–0.09 per cent concentration were evaluated through two modes of application viz., topical and oral. Acetylcholinesterase (AChE) activity was measured at various intervals (1 and 24 hours) to assess enzyme inhibition. Behavioral observations and statistical analyses, including factor analysis with Eigen values, were employed to evaluate the impact of exposure on bee behavior and physiological responses.The results revealed two factors with Eigen value > 0.95 in both topical as well as oral method which accounted for 88.28 and 88.80 per cent of the variation in behaviour, respectively. Insecticides applied to honey bee A. mellifera in both topical as well as oral methods resulted in significant inhibition of the Acetyl choline esterase enzyme (AChE) activity. Studies revealed higher AChE inhibition (%) in oral method as compared to topical method. AChE inhibition percentage increased from 25.15 (1 Hour after treatment) to 58.25 (24 Hours after treatment) with lower concentration (0.005) of chlorpyriphos in topical method while as it reached from 27.66 to 60.94 with same concentration and same time in oral method of application. AChE inhibition percentage increased from 35.81 (1 Hour after treatment) to 78.30 (24 Hours after treatment) with higher concentration (0.06) of chlorpyriphos in topical method while as it reached from 40.35 to 80.18 with same concentration and same time in oral method. Similar trend was observed in dimethoate, and profenophos where AChE inhibition increased from 17.30, 27.15 (1 Hour after treatment) to 57.18, 61.81 (24 Hours after treatment), respectively in topical method and 20.67, 28.80 (1 Hour after treatment) to 59.85 64.04 (24 Hours after treatment), respectively in oral method. Similarly, with higher concentrations of dimethoate (0.07), and profenophos (0.09), per cent inhibition increased from 34.54, 38.60 (1 Hour after treatment) to 75.68, 79.62 (24 Hours after treatment), in topical method and 37.25, 41.23 (1 Hours after treatment) to 77.86, 82.73 (24 Hours after treatment), in oral method, respectively. Thorough risk assessments are vital for evaluating the effects of agrochemicals on Apis mellifera. The findings highlight the necessity for updated pesticide regulations and broadened conservation strategies that take into account the diverse ways pollinators are exposed to agrochemicals in the environment. The study assessed the impact of different insecticides on Apis mellifera by comparing topical and oral exposure methods. The study also aimed to analyze the behavioral effects of insecticide exposure on Apis mellifera, assessing variations in response and enzyme inhibition.The research focused on evaluating Acetylcholinesterase (AChE) inhibition to better understand the risks posed to honeybees in agricultural environments.

The Effect of Hive Type on Colony Homeostasis and Performance in the Honey Bee (Apis mellifera).

The colonies of honey bees are mostly sessile organisms. Consequently, the type of nest boxes that beekeepers provide to their bees should impact a colony's ability to maintain homeostasis, which is a key determinant of performance and fitness. Here, we used European honey bees (Apis mellifera) and provided them with two hive setups widely used and known as Langstroth and Warré. We compared colony performance in a Mediterranean climate for five months from late spring to early autumn, which covered the most active time of bees and included periods of heat and drought. We found that irrespective of hive type or season, honey bees kept hive temperature and humidity within a remarkably narrow range. Nevertheless, the hive type impacted the daily fluctuations in temperature and humidity. In Warré hives, where bees have more autonomy to build and maintain their combs, we found that bees were able to reduce daily fluctuations in temperature and humidity and kept both measures closer to the overall average. This increase in colony homeostasis found in Warré hives negatively correlated with other hive performance indicators, such as immunocompetence. We conclude that different hive types affect key areas, such as the central part of the colony with frames of developing brood or the queen, which are the most susceptible individuals. This implies that climatic changes resulting in extreme weather events are expected to impact colony performance and fitness, especially in non-managed honey bees that are limited by available nesting sites. For managed bees, adaptations to existing hive setups could be provided to help bees minimize the effects of abiotic stress.

Targeted viromes and total metagenomes capture distinct components of bee gut phage communities

BackgroundDespite being among the most abundant biological entities on earth, bacteriophage (phage) remain an understudied component of host-associated systems. One limitation to studying host-associated phage is the lack of consensus on methods for sampling phage communities. Here, we compare paired total metagenomes and viral size fraction metagenomes (viromes) as methods for investigating the dsDNA viral communities associated with the GI tract of two bee species: the European honey bee Apis mellifera and the eastern bumble bee Bombus impatiens.ResultsWe find that viromes successfully enriched for phage, thereby increasing phage recovery, but only in honey bees. In contrast, for bumble bees, total metagenomes recovered greater phage diversity. Across both bee species, viromes better sampled low occupancy phage, while total metagenomes were biased towards sampling temperate phage. Additionally, many of the phage captured by total metagenomes were absent altogether from viromes. Comparing between bees, we show that phage communities in commercially reared bumble bees are significantly reduced in diversity compared to honey bees, likely reflecting differences in bacterial titer and diversity. In a broader context, these results highlight the complementary nature of total metagenomes and targeted viromes, especially when applied to host-associated environments.ConclusionsOverall, we suggest that studies interested in assessing total communities of host-associated phage should consider using both approaches. However, given the constraints of virome sampling, total metagenomes may serve to sample phage communities with the understanding that they will preferentially sample dominant and temperate phage.6S3bFgh36a8k5RNed1PpF4Video

Sacbrood viruses and select Lake Sinai virus variants dominated Apis mellifera colonies symptomatic for European foulbrood.

European foulbrood (EFB) is a prevalent disease in the European honey bee (Apis mellifera) in the United States, which can lead to colony decline and collapse. The bacterial components of EFB are well-studied, but the diversity of viral infections within infected colonies has not been explored. In this study, we use meta-transcriptomics sequencing of 12 honey bee hives, symptomatic (+, n = 6) and asymptomatic (-, n = 6) for EFB, to investigate viral infection associated with the disease. We assembled 41 viral genomes, belonging to three families (Iflaviridae, Dicistroviridae, and Sinhaliviridae), all previously reported in honey bees, including Lake Sinai virus, deformed wing virus, sacbrood virus, Black queen cell virus, and Israeli acute paralysis virus. In colonies with severe EFB, we observed a higher occurrence of viral genomes (34 genomes) in contrast to fewer recovered from healthy colonies (seven genomes) and a complete absence of Dicistroviridae genomes.We observed specific Lake Sinai virus clades associated exclusively with EFB + or EFB - colonies, in addition to EFB-afflicted colonies that exhibited an increase in relative abundance of sacbrood viruses. Multivariate analyses highlighted that a combination of site and EFB disease status influenced RNA virome composition, while EFB status alone did not significantly impact it, presenting a challenge for comparisons between colonies kept in different yards. These findings contribute to the understanding of viral dynamics in honey bee colonies compromised by EFB and underscore the need for future investigations to consider viral composition when investigating EFB.IMPORTANCEThis study on the viromes of honey bee colonies affected by European foulbrood (EFB) sheds light on the dynamics of viral populations in bee colonies in the context of a prevalent bacterial brood disease. The identification of distinct Lake Sinai virus and sacbrood virus clades associated with colonies affected by severe EFB suggests a potential connection between viral composition and disease status, emphasizing the need for further investigation into the role of viruses during EFB infection. The observed increase in sacbrood viruses during EFB infection suggests a potential viral dysbiosis, with potential implications for honey bee brood health. These findings contribute valuable insights related to beekeeping practices, offering a foundation for future research aimed at understanding and mitigating the impact of bacterial and viral infection in commercial honey bee operations and the management of EFB.

Investigation of landscape risk factors for the recent spread of varroa mite (Varroa destructor) in European honeybee (Apis mellifera) colonies in New South Wales, Australia.

In June 2022, an exotic pest of the European honeybee (Apis mellifera), the varroa mite (Varroa destructor), was detected in surveillance hives at the Port of Newcastle, New South Wales (NSW). Previously, Australia remained the only continent free of the varroa mite. In September 2023, the National Management Group decided to shift the focus of the response from eradication to management. It is estimated that the establishment of varroa mite in Australia could lead to more than $70 million in losses each year due to greatly reduced pollination services. Currently, there are no reported studies on the epidemiology of varroa mite in NSW because it is such a recent outbreak, and there is little knowledge of the factors associated with the presence of V. destructor in the Australian context. We sourced publicly available varroa mite outbreak reports from June 22 to December 19, 2022, to determine if urbanization, land use, and distance from the incursion site are associated with the detection of varroa mite infestation in European honeybee colonies in NSW. The outcome investigated was epidemic day, relative to the first detected premises (June 22, 2022). The study population was comprised of 107 premises, which were declared varroa-infested. The median epidemic day was day 37 (July 29, 2022), and a bimodal distribution was observed from the epidemic curve, which was reflective of an intermittent source pattern of spread. We found that premises were detected to be infected with varroa mite earlier in urban areas [median epidemic day 25 (July 17, 2022)] compared to rural areas [median epidemic day 37.5 (July 29, 2022)]. Infected premises located in areas without cropping, forests, and irrigation were detected earlier in the outbreak [median epidemic days 23.5 (July 15, 2022), 30 (July 22, 2022), and 15 (July 7, 2022), respectively] compared to areas with cropping, forests, and irrigation [median epidemic days 50 (August 11, 2022), 43 (August 4, 2022), and 47 (August 8, 2022), respectively]. We also found that distance from the incursion site was not significantly correlated with epidemic day. Urbanization and land use are potential factors for the recent spread of varroa mite in European honeybee colonies in NSW. This knowledge is essential to managing the current varroa mite outbreak and preventing future mass varroa mite spread events.

Pollination by birds, non-flying mammals, and European honeybees in a heathland shrub, Banksia catoglypta (Proteaceae)

Abstract Vertebrate pollination has evolved in many plant lineages, with pollination by birds the most prevalent strategy. However, in Banksia (Proteaceae) many species are visited by a combination of nectarivorous birds, non-flying mammals (NFMs), and insects, though the relative importance of these pollen vectors for reproduction remains poorly understood. Here, we investigate the contribution to fruit set of birds, NFMs, and insects in Banksia catoglypta—a heathland shrub from south-west Australia. This species flowers in winter and produces large, golden-yellow inflorescences that are typically presented near the ground and consist of rigid, strongly scented flowers with a long stigma-nectary distance—suggesting pollination by vertebrates. The primary floral visitors were white-cheeked honeyeaters (Phylidonyris niger), honey possums (Tarsipes rostratus), house mice (Mus musculus), and introduced European honeybees (Apis mellifera), all of which carried B. catoglypta pollen. Banksia catoglypta was found to be obligately outcrossing with no evidence of pollen limitation. Selective exclusion of flying pollinators revealed that inflorescences pollinated solely by NFMs produced 50% fewer fruit than open-pollinated controls. Therefore, while mammals are pollinators of B. catoglypta, they may contribute comparatively little to fruit set in some Banksia species displaying floral traits considered adaptations to NFM pollination. Exclusion of vertebrate pollinators had no effect on fruit set, demonstrating that European honeybees can be effective pollinators of some primarily vertebrate-pollinated plants.

Can Bees Detect Perfluorooctane Sulfonate (PFOS)?

The European honey bee (Apis mellifera) is an important crop pollinator threatened by multiple stressors, including exposure to contaminants. Perfluorooctane sulfonate (PFOS) is a persistent global contaminant that accumulates and biomagnifies in food chains and is detected in honey. Even sublethal exposure to PFOS is detrimental to bee health, but exposure routes are unclear and nothing is known about bee response (detection, avoidance, or attraction) to PFOS. Using Y-mazes, we studied the response of individual bees to PFOS-spiked sugar syrup at four concentrations, 0.02, 30, 61 and 103 µg L-1. Bee activity, choice behavior, and drink duration for unspiked and spiked sugar syrup was recorded for 10 min in the Y-maze system. Most bees (≥80%) tasted and then drank the sugar syrup solutions, including the PFOS-contaminated syrup. Only at 61 and 103 µg L-1 did bees significantly avoid drinking PFOS-spiked syrup, and only when given a choice with unspiked syrup. When the choice of consuming unspiked syrup was removed, the bees drank PFOS-spiked syrup at all the PFOS concentrations tested, and avoidance was not evident. Avoidance was not observed in any treatment at 0.02 or 30 µg L-1 PFOS, concentrations that are frequently reported in environmental waters in contaminated areas. These findings confirm that bees will access PFOS-contaminated resources at concentrations detrimental to the colony health, and provide evidence of potential exposure pathways that may threaten crop pollination services and also human health via food chain transfer in PFOS-contaminated areas. Environ Toxicol Chem 2024;43:1638-1647. © 2024 SETAC.

The dark European honey bee Apis mellifera mellifera in Lithuania: data on mitotype diversity of native bee population

In Europe, the population of the dark European honey bee Apis mellifera mellifera L. has been significantly affected by the introduction and propagation of non-indigenous subspecies of honey bees. For a long time, the status of the native Lithuanian A. m. mellifera bees was unknown. Thus, the aim of this study was to determine the current distribution of the subspecies population in Lithuania and the diversity of its mitotypes. A total of 598 honey bee colonies from traditionally managed apiaries were studied to determine their maternal ancestry using the COI–COII intergenic spacer sequences of mtDNA. The results revealed that 52% of the maternal lines investigated belonged to A. m. mellifera. They represented 20 unique COI–COII intergenic spacer mitotypes, 11 of which were detected for the first time. We hypothesised that a small proportion of ancestral A lineage mitotypes among the dominant M lineage mitotypes could be the relict of the maternal line.

Amplicon and Cas9-targeted nanopore sequencing of Varroa destructor at the onset of an outbreak in Australia

Varroa destructor is a major pest of European honey bees (Apis mellifera), causing significant economic and welfare impacts. Australia remained the last continent free from V. destructor. In June 2022, a detection of V. destructor was reported in sentinel colonies at the Port of Newcastle, Australia. Rapid and accurate identification of the species was critical for timely response and management. In this case study, two Nanopore DNA sequencing methods, PCR amplicon sequencing and Cas9-targeted sequencing, were used to rapidly diagnose the species and mitochondrial haplotype of Varroa mites in parasitized colonies. Nanopore PCR amplicon sequencing provided molecular identification of the species and halogroup determination within 24 hours based on a 458 bp amplicon of the mitochondrial Cytochrome c oxidase subunit I (COXI) gene. We also developed and applied a Cas9-targeted Nanopore sequencing technique that used eight guide RNAs to enrich for 5240 bp of the mitochondrial genome. This method delivered richer data for identification within the same timeframe. Our results underscore the efficacy of Nanopore amplicon sequencing and represent the first reported application of Cas9-targeted Nanopore sequencing within a biosecurity framework. These findings enhance the repertoire of diagnostic tools available for biosecurity applications.

Gut microbiota contribute to variations in honey bee foraging intensity.

Gut microbiomes are increasingly recognized for mediating diverse biological aspects of their hosts, including complex behavioral phenotypes. Although many studies have reported that experimental disruptions to the gut microbial community result in atypical host behavior, studies that address how gut microbes contribute to adaptive behavioral trait variation are rare. Eusocial insects represent a powerful model to test this, because of their simple gut microbiota and complex division of labor characterized by colony-level variation in behavioral phenotypes. Although previous studies report correlational differences in gut microbial community associated with division of labor, here, we provide evidence that gut microbes play a causal role in defining differences in foraging behavior between European honey bees (Apis mellifera). We found that gut microbial community structure differed between hive-based nurse bees and bees that leave the hive to forage for floral resources. These differences were associated with variation in the abundance of individual microbes, including Bifidobacterium asteroides, Bombilactobacillus mellis, and Lactobacillus melliventris. Manipulations of colony demography and individual foraging experience suggested that differences in gut microbial community composition were associated with task experience. Moreover, single-microbe inoculations with B. asteroides, B. mellis, and L. melliventris caused effects on foraging intensity. These results demonstrate that gut microbes contribute to division of labor in a social insect, and support a role of gut microbes in modulating host behavioral trait variation.

Effect of dietary supplement on the reproductive traits, products and behavioral characteristics of the European honey bee (Apis mellifera)

We evaluated the effects of dietary supplements on hive populations of the European honey bee (Apis mellifera) through experimental trials. The population, reproduction rate, quality of honey, quantity and quality of venom, and behavioral characteristics of 15 hives were assessed in a randomized experimental design with three groups and five replicates. Each replicate contained one modern Langstroth–Hive. The experimental period was 86 days, and each hive in the control group (control), received 500 mL syrup without dietary supplement per day (sugar and water in equal quantities), Group 1 received 500 mL syrup with 5 g dietary supplement added, and Group 2 received 500 mL syrup with 10 g dietary supplement added. The colony population and reproduction rate increased significantly in both treatment groups (p < 0.01). Honey production increased significantly in Group 2 (p < 0.05). Diastase activity and protein and sucrose content in honey increased significantly in both groups (p < 0.05). The general behavior of the bees improved significantly in both groups (p < 0.01). Aggressive behavior decreased significantly in Group 2 (p < 0.01). Overall, Group 2 showed statistically significant improvements which were better than Group 1.

Free-living colonies of native honey bees (Apis mellifera mellifera) in 19th and early 20th century Sweden

Little information exists on the history and ecology of free-living colonies of European honey bees (Apis mellifera L.) in Europe, including its dark north-western subspecies (Apis mellifera mellifera). Our aim was to investigate the presence of colonies of free-living, native honey bees (A. m. mellifera) during the last two centuries in Sweden. For this we examined systematic interviews of beekeepers (176 answers from 158 questionnaires) performed in the years 1928–1981, with information dating back to the early 1800s. An overwhelming majority of answers (96%) confirmed the past presence of free-living colonies of honey bees in Sweden. While some stated that free-living colonies were simply absconded swarms from managed hives, the majority of interviewees (69%) believed that free-living colonies were of a truly wild origin. A decreasing trend in first-hand accounts of free-living colonies suggests that free-living populations underwent a dramatic decline at the end of the 19th century. This was also expressed in words by many interviewees, who in 14 cases stated that the loss of old forests and tree-cavity nest sites at the end of the 1800s was the primary cause of the decline. Direct accounts of perennial, free-living colonies, combined with detailed descriptions of the collection of large free-living colonies and/or wild honey, is strong evidence of free-living honey bees being well adapted to winter survival. These accounts contradict the officially supported view that the honey bee is a recently imported, domesticated, non-native species in Sweden. The results give a scientific underpinning and provide inspiration for the restoration of native forests which could facilitate populations of free-living colonies of A. m. mellifera exposed to natural selection. This could potentially lead to its return as a fully wild species. In an uncertain future, allowing for a natural lifestyle could increase resilience and reinstate characteristics that are otherwise lost in honey bees due to the increasing effects of artificial trait selection.Implications for insect conservationOur results present strong evidence for populations of free-living colonies of A. m. mellifera in the recent past, which calls for a revised look at its conservation status and management. Allowing and supporting free-living colonies of this subspecies should be evaluated as a method for conservation.

Annotated checklist of the Swiss bees (Hymenoptera, Apoidea, Anthophila): hotspots of diversity in the xeric inner Alpine valleys

We present a checklist of the Swiss bees and provide information on the distribution of every bee species in all 26 Swiss cantons. 632 species are reported, including the European honeybee Apis mellifera Linnaeus, 1758 and the exotic species Megachile sculpturalis Smith, 1853. Species richness in each canton was correlated with the canton area, with the four largest cantons hosting the highest number of species. Bee diversity hotspots were located in some Alpine inner valleys characterized by a dry and warm climate due to the rain shadow effects of surrounding mountains. These hotspots are mostly located in the steppe-like habitats of the Valais and Graubünden cantons. They host diverse wild bee communities which include a unique assemblage of submediterranean faunal elements and subalpine species. In addition, these habitats host rare species with strongly disjunct distributions in Europe, further stressing the conservation priority of these habitats for wild bee conservation. Intensive faunistic surveys performed in the last 20 years have revealed that about 20 bee species, either previously unknown for Switzerland or which had disappeared from the country for several decades, have colonised areas close to the borders of France and Italy. Most of these new or reappeared species were observed in the warmest area of the country and presumably colonized or recolonized the country from neighbouring regions following global warming. Lastly, DNA barcodes are presented for 394 specimens, including for many species so far not represented in the BOLD database. The taxonomic status of numerous unclear taxa is briefly discussed based on combined genetic and morphological analyses.

The golden native drone fly (Eristalinus punctulatus) is an effective hybrid carrot pollinator that lives within Australian crop agroecosystems

Abstract Native insect flower visitors can be important contributors to crop pollination, yet little is known of their pollination abilities and the resources (habitat) they need to be supported within crop agroecosystems. Here, we compared the abundance and pollination abilities of the golden drone fly (Eristalinus punctulatus) to the European honey bee (Apis mellifera) in hybrid carrot crop fields known to produce variable seed yields in regional New South Wales, Australia. We further observed the egg‐laying behaviours of female golden drone flies at a commercial berry orchard to provide insight into the habitat needs of this species. In hybrid carrot crop fields, golden drone flies were far less abundant flower visitors than European honey bees; however, these flies deposited more carrot pollen grains on average (8.21 ± 3.04 SE) onto carrot flowers than European honey bees (3.45 ± 1.06 SE). Both insects also deposited pollen onto a similar number of carrot flowers (pollinated) per visit (about 2 out of 18). Golden drone flies were observed laying eggs within masses of discarded red raspberry plant roots and soil (root balls) at a commercial berry orchard. The natural habitat utilised by these flies, as well as their egg‐laying behaviours, were described for the first time. Our results indicate that golden drone flies are effective pollinators of hybrid carrot crop plants. The habitat that these flies utilised to lay eggs (discarded plants and water) is cheap and commonly found in crop agroecosystems. Therefore, we recommend placing this low‐cost habitat within, or nearby, crop fields as a potential management practice to support the lifecycle needs of golden drone flies and other non‐bee pollinators.

Differences in the suitability of published honey bee (Apis mellifera) reference genes between the African subspecies Apis mellifera scutellata and European derived Apis mellifera.

Quantitative real-time polymerase chain reaction (qPCR) is a method widely used to determine changes and differences in gene expression. As target gene expression is most often quantified relative to the expression of reference genes, the validation of suitable reference genes is of critical importance. In practice, however, such validation might not be thoroughly conducted if the same species and the same tissue or body parts are used for qPCR experiments. Here we show, that qPCR reference genes published for workers of European honey bee (Apis mellifera) subspecies fail to be stably expressed in workers of the African subspecies Apis mellifera scutellata. This is the case even when the sampled workers are in the same life stage, the same organ was dissected and the same reagents were used. Thus, reference genes need to be thoroughly re-tested before they can be used as suitable references even when the only thing that changes is the subspecies used.

Image background assessment as a novel technique for insect microhabitat identification

Habitat fragmentation under increased urbanisation, industrial agriculture and land clearing, are changing the way insects occupy habitat. Some species are highly adaptable and may occupy urbanised areas, utilising anthropogenic microhabitat-scale features. Other species are dependent on natural elements of their habitats, having to locate small regions of natural microhabitat within increasingly hostile landscapes. Consequently, humans are encountering insects in new settings. Identifying and analysing insects’ use of natural and anthropogenic microhabitats is therefore important to assess their responses to a changing environment, for instance to improve pollination or manage invasive pests. But such studies are labour-intensive.Traditional studies of insect microhabitat use can now be supplemented by machine learning-based insect image analysis. Typically, research has focused on automatic insect classification, but valuable data appearing in image backgrounds has been ignored. In this research, we analysed the backgrounds of insect images available in the Atlas of Living Australia database to determine the microhabitats in which they were commonly photographed. We analysed the image backgrounds of three globally distributed insect species that are common across Australia: Drone flies (Eristalis tenax), European honey bees (Apis mellifera), and European wasps (Vespula germanica). Image backgrounds were classified broadly as either natural or anthropogenic using computer vision and machine learning tools benchmarked against a manual classification algorithm.Our automated image background classification achieved 97.4% accuracy when compared against manual classification. Mis-classifications were scarce, usually less than 1%, and primarily for backgrounds of wood and soil or bare ground. Our results indicate that drone flies and European honey bees were predominantly photographed against natural backgrounds (flies manual classifier 95±3%, automated classifier 94%, bees 89±2%,87%), implying frequent observations by humans in natural microhabitat. European wasps were less frequently photographed against natural backgrounds (70±6%,63%). Within this data set, observations of the wasps in anthropogenic microhabitats were more common than for flies and bees.Our results are aligned with the expectation that the wasps are relatively well-suited to urban environments, and that European honey bees and drone flies utilise natural features of their environment. In general, although biases in data collected without formal protocols limits their application, our new automated approach for image background analysis can provide valuable data about insects’ interactions with humans, our artefacts, and natural features of their environments.

Can the examination of different types of hive samples be a non-invasive method for detection and quantification of viruses in honey bee (Apis mellifera L.) colonies?

Honey bee viruses have been shown to negatively affect the vigour and longevity of European honey bees (Apis mellifera L). In the present work, beehive materials were tested for their potential to serve as non-invasive samples for honey bee virus detection. Honey, pollen, hive debris, hive grid smears and forager honey bees were collected from 24 hives at four locations in the Czech Republic. Deformed wing virus (DWV), acute bee paralysis virus (ABPV), sacbrood virus (SBV) and black queen cell virus (BQCV) were detected using a reverse transcription PCR (RT-PCR) and real-time quantitative RT-PCR and the results for bees and alternative materials compared. All forager bee samples contained DWV, BQCV and SBV and 54.2% had ABPV. When comparing beehive materials to bees, the most promising results were obtained from honey and pollen samples, with BQCV and SBV detected in all honey samples and ABPV in 12.5%. Detection of SBV was achieved in 91.6% of pollen samples, detection of BQCV in 87.5% and detection of DWW in 75%. The results for debris and smears were less consistent with the viral profile of the forager samples. The best candidate materials for honey bee virus detection in a non-invasive technique are honey and pollen.

Dim-light colour vision in the facultatively nocturnal Asian giant honeybee, Apis dorsata.

We discovered nocturnal colour vision in the Asian giant honeybee Apis dorsata-a facultatively nocturnal species-at mesopic light intensities, down to half-moon light levels (approx. 10-2 cd m-2). The visual threshold of nocturnality aligns with their reported nocturnal activity down to the same light levels. Nocturnal colour vision in A. dorsata is interesting because, despite being primarily diurnal, its colour vision capabilities extend into dim light, while the 'model' European honeybee Apis mellifera is reported to be colour-blind at twilight. By employing behavioural experiments with naturally nesting A. dorsata colonies, we show discrimination of the trained colour from other stimuli during the day, and significantly, even at night. Nocturnal colour vision in bees has so far only been reported in the obligately nocturnal carpenter bee Xylocopa tranquebarica. The discovery of colour vision in these two bee species, despite differences in the extent of their nocturnality and the limitations of their apposition compound eye optics, opens avenues for future studies on visual adaptations for dim-light colour vision, their role in pollination of flowers at night, and the effect of light pollution on nocturnal activity in A. dorsata, a ubiquitous pollinator in natural, agricultural and urban habitats in the Asian tropics and sub-tropics.