A scientific note on the natural merger of two honeybee colonies (Apis mellifera capensis)

Natural mergers of honeybee colonies are commonplace in tropical Africa (Hepburn and Radloff, 1998), but their consequences on organizational structure are unknown. Here we determine the spatial distribution and division of labor of workers (Apis mellifera capensis Esch.) following a merger of two colonies. Two unrelated colonies (each ~3000 bees) were placed in threeframe observation hives. When workers emerged from the sealed brood of each colony, they were individually labeled and reintroduced into their respective mother hives. They are referred to as cohorts Aand B, each comprising 300 workers of the same age. The behaviors and positions of all labeled workers and queens were recorded twice daily for 24 days (Kolmes, 1989; Pirk et al., 2000). On day 14 colony B was dequeened, left its nest and merged with colony A on day 15

Honey bees save energy in honey processing by dehydrating nectar before returning to the nest

Honey bees process nectar into honey by active evaporation on the tongue and passive evaporation involving nest ventilation and fanning behaviour, as well as enzymatic action. The elimination of excess water from nectar carries considerable energetic costs. The concentration of the nectar load is assumed to remain constant during transport. However, some of this water elimination may occur before foragers return to the nest and pass their nectar loads to receiver bees. In honey bees captured while foraging in Macadamia orchards, we show that the nectar in their crops has approximately twice the sugar concentration of the fresh nectar in fowers. This was true for four Macadamia cultivars, with up to 75% of the initial water content being removed. There is a further concentration increase in the crops of returning bees captured at the hive entrance. The only possible route of water elimination from the crop is via evaporation from the mouthparts. We calculate the savings in honey processing costs to be on average 35 times more than the reduction in fight costs due to reduced body mass. Pre-concentration of nectar in foraging honey bees may be widespread, and of crucial importance for honey storage.SAMAChttps://www.nature.com/srepZoology and Entomolog

Spatial variability of CO \u3c inf\u3e 2 uptake in polygonal tundra: Assessing low-frequency disturbances in eddy covariance flux estimates

The large spatial variability in Arctic tundra complicates the representative assessment of CO2 budgets. Accurate measurements of these heterogeneous landscapes are, however, essential to understanding their vulnerability to climate change. We surveyed a polygonal tundra lowland on Svalbard with an unmanned aerial vehicle (UAV) that mapped ice-wedge morphology to complement eddy covariance (EC) flux measurements of CO2. The analysis of spectral distributions showed that conventional EC methods do not accurately capture the turbulent CO2 exchange with a spatially heterogeneous surface that typically features small flux magnitudes. Nonlocal (low-frequency) flux contributions were especially pronounced during snowmelt and introduced a large bias of -46 gCm-2 to the annual CO22 budget in conventional methods (the minus sign indicates a higher uptake by the ecosystem). Our improved flux calculations with the ogive optimization method indicated that the site was a strong sink for CO2 in 2015 (82 gCm2). Due to differences in light-use efficiency, wetter areas with lowcentered polygons sequestered 47% more CO2 than drier areas with flat-centered polygons. While Svalbard has experienced a strong increase in mean annual air temperature of more than 2K in the last few decades, historical aerial photographs from the site indicated stable ice-wedge morphology over the last 7 decades. Apparently, warming has thus far not been sufficient to initiate strong ice-wedge degradation, possibly due to the absence of extreme heat episodes in the maritime climate on Svalbard. However, in Arctic regions where ice-wedge degradation has already initiated the associated drying of landscapes, our results suggest a weakening of the CO2 sink in polygonal tundra

Honeybees and nectar nicotine : deterrence and reduced survival versus potential health benefits

Secondary metabolites produced by plants for herbivore defence are often found in floral nectar, but their effect on the foraging behaviour and physiological performance of pollinators is largely unknown. Nicotine is highly toxic to most herbivores, and nicotine-based insecticides may contribute to current pollinator declines. We examined the effects of nectar nicotine on honeybee foraging choices and worker longevity. Free-flying honeybee (Apis mellifera scutellata) workers from six colonies were given a choice between multiple nicotine concentrations (0–1000 lM) in artificial nectar (0.15–0.63 M sucrose). The dose-dependent deterrent effect of nicotine was stronger in lower sugar concentrations, but even the highest nicotine concentrations did not completely repel honeybees, i.e. bees did not stop feeding on these diets. Nicotine in nectar acts as a partial repellent, which may keep pollinators moving between plants and enhance cross-pollination. In the second part of the study, newly emerged workers from 12 colonies were caged and fed one of four nicotine concentrations (0–300 lM) in 0.63 M sucrose for 21 days. Moderate (630 lM) nicotine concentrations had no significant detrimental effect, but high nicotine concentrations reduced the survival of caged workers and their nectar storage in the honey comb. In contrast, worker groups that survived poorly on sugar-only diets demonstrated increased survival on all nicotine diets. In the absence of alternative nectar sources, honeybees tolerate naturally occurring nectar nicotine concentrations; and low concentrations can even be beneficial to honeybees. However, high nicotine concentrations may have a detrimental effect on colony fitness.http://www.elsevier.com/ locate/ jinsphyshb2014ab201

Reproductive traits and mandibular gland pheromone of anarchistic honey bee workers Apis mellifera occurring in China

International audienceAbstractIn honey bee colonies, workers, in particular of “anarchistic” lineages, can activate their ovaries and lay eggs, even in the presence of the queen. We identified three queenright colonies showing typical signs of worker reproduction. To characterize this new lineage, we extracted the mandibular gland and analyzed it using gas chromatography. The total amounts of the five main components of the mandibular gland, namely methyl p-hydroxyben-zoate (HOB), 9-oxo-2(E)-decenoic acid (9-ODA), (S)-9-hydroxy-(E)-2-decenoic acid (9-HDA), 10-HDA, and 10-hydroxyde-canoic acid (10-HDAA) were significantly higher in the mandibular gland profiles of workers with activated ovaries (AWs, 8.88 ± 1.71 μg) compared to workers with inactivated ovaries (IAWs, 4.00 ± 2.09 μg). Furthermore, the chemical profiles of IAWs were dominated by the “worker substances” 10-HDA (34.64 ± 8.19 %) and its precursor 10-HDAA (22.88 ± 4.95 %), while the chemical profiles in AWs were dominated by the precursor of the queen substance 9-HDA (40.04 ± 7.55 %). The ratios of two precursor substances 10-HDAA/9-HDA of IAWs were more worker like (>1.0) whereas AWs were more queen like (≤1.0). These results suggest that the mandibular pheromones of anarchistic workers resemble a more queen-like reproductive active profile and that these workers may represent a reversion to a more basal reproductive phenotype

A new design for honey bee hoarding cages for laboratory experiments

Honey bees are the subject of research around the world due to their great economic importance and current population declines (vanEngelsdorp and Meixner, 2010). Many studies cannot be conducted at the colony level. Controlled cage experiments provide insight into behavioural interactions (Elzen et al., 2001), diseases (Martín-Hernández et al., 2009), nutritional requirements (Altaye et al., 2010) and effects of insecticides and genetically engineered plants on these important pollinators (Malone et al., 1999; Medrzycki et al., 2003).A grant from BBSRC, Defra, NERC, the Scottish Government and the Wellcome Trust, under the Insect Pollinators Initiative (BBI000968/1)http://www.ibra.org.uk/am2014ab201

The northernmost hyperspectral FLoX sensor dataset for monitoring of high-Arctic tundra vegetation phenology and Sun-Induced Fluorescence (SIF)

A hyperspectral field sensor (FloX) was installed in Adventdalen (Svalbard, Norway) in 2019 as part of the Svalbard Integrated Arctic Earth Observing System (SIOS) for monitoring vegetation phenology and Sun-Induced Chlorophyll Fluorescence (SIF) of high-Arctic tundra. This northernmost hyperspectral sensor is located within the footprint of a tower for long-term eddy covariance flux measurements and is an integral part of an automatic environmental monitoring system on Svalbard (AsMovEn), which is also a part of SIOS. One of the measurements that this hyperspectral instrument can capture is SIF, which serves as a proxy of gross primary production (GPP) and carbon flux rates. This paper presents an overview of the data collection and processing, and the 4-year (2019–2021) datasets in processed format are available at: https://thredds.met.no/thredds/catalog/arcticdata/infranor/NINA-FLOX/raw/catalog.html associated with https://doi.org/10.21343/ZDM7-JD72 under a CC-BY-4.0 license. Results obtained from the first three years in operation showed interannual variation in SIF and other spectral vegetation indices including MERIS Terrestrial Chlorophyll Index (MTCI), EVI and NDVI. Synergistic uses of the measurements from this northernmost hyperspectral FLoX sensor, in conjunction with other monitoring systems, will advance our understanding of how tundra vegetation responds to changing climate and the resulting implications on carbon and energy balance. Chlorophyll fluorescenceSolar Induced Fluorescence (SIF)ReflectancePhotosynthetic functionMERIS terrestrial chlorophyll index (MTCI)High-Arctic tundrapublishedVersio