Brood Pheromone Foraging

Foraging experiments conducted as described in Ma et al 2018 during Summer 2015. Camera indicates the recording equipment used to record foraging. Colony ID identifies each unique colony, that were randomly assigned Screen treatments. Repeated measures were conducted for 3 different pheromone treatments on 3 different Days. Foraging was recorded at 3 time points following pheromone treatment. The number of foaragers carrying pollen or not carrying pollen were recorded

EAG_2016

Electroantennography (EAG) data associated with Ma et al 2018. Colony represents the source colony from which individual nurses and foragers were taken. Behavior categorizes individual bees as nurses or foragers. Four concentrations for each of two pheromones were used for the analysis. Raw values were divided by eag response to average of hexane controls to produce standardized responses. Hexane responses were taken before and after pheromone exposure

BPO Forage May2018

R code in Rmarkdown format used to analyze foraging data

EAG May 2018

R code in Rmarkdown format used to anlayze EAG data

Honey Bee (<i>Apis mellifera</i>) Queen Reproductive Potential Affects Queen Mandibular Gland Pheromone Composition and Worker Retinue Response

<div><p>Reproductive division of labor is one of the defining traits of honey bees (<i>Apis mellifera</i>), with non-reproductive tasks being performed by workers while a single queen normally monopolizes reproduction. The decentralized organization of a honey bee colony is maintained in large part by a bouquet of queen-produced pheromones, the distribution of which is facilitated by contact among workers throughout the hive. Previous studies have shown that the developmental fate of honey bee queens is highly plastic, with queens raised from younger worker larvae exhibiting higher measures of reproductive potential compared to queens raised from older worker larvae. We investigated differences in the chemical composition of the mandibular glands and attractiveness to workers of “high-quality” queens (i.e., raised from first instar worker larvae; more queen-like) and “low-quality” queens (i.e., raised from third instar worker larvae; more worker-like). We characterized the chemical profiles of the mandibular glands of high-quality queens and low-quality queens using GC-MS and used the worker retinue response as a measure of the attractiveness to workers of high-quality queens vs. low-quality queens. We found that queen quality affected the chemical profiles of mandibular gland contents differently across years, showing significant differences in the production of the queen mandibular pheromone (“QMP”) components HVA and 9-HDA in 2010, but no significant differences of any glandular compound in 2012. We also found that workers were significantly more attracted to high-quality queens than to low-quality queens in 2012, possibly because of increased attractiveness of their mandibular gland chemical profiles. Our results indicate that the age at which honey bee larvae enter the “queen-specific” developmental pathway influences the chemical composition of queen mandibular glands and worker behavior. However, these changes are not consistent across years, suggesting that other external factors may play important roles in modulating queen quality.</p></div

Compounds identified using GC-MS from mandibular gland extracts of honey bee queens that were either raised from first-instar worker larvae (i.e., "high-quality" queens) or third-instar worker larvae (i.e., "low-quality" queens) in 2010 and 2012.

<p>The relative amount (in %) of each compound is given for each treatment group (mean ± s.e.m.). Kovats index values were calculated for the <i>N</i>-methyl-<i>N</i>-(trimethylsilyl)-trifluoroacetamide (MSTFA) derivatives obtained from the GC retention times. Differences in relative amounts of compounds between high-quality queens and low-quality queens were analyzed with two-tailed non-parametric Wilcoxon tests because of unequal variances. All tests were performed separately for queens raised in 2010 and queens raised in 2012 (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0156027#sec002" target="_blank">Methods</a> for details).</p

Levels of worker attraction to honey bee queens varied during retinue response bioassays depending on the age at which a worker larvae are chosen to be raised as queen (i.e., "grafting age," see Methods for details).

<p>Worker retinue size was significantly higher when observation colonies were headed by queens raised from first instar worker larvae (i.e., "high-quality" queens) compared to those headed by queens raised from third instar worker larvae (i.e., "low-quality" queens). The total number of instantaneous sampling points for each queen type (n) is denoted within each bar. Retinue size across both treatments was compared with a matched-pair t-test (* <i>P</i> < 0.0001).</p

Modulation of the honey bee queen microbiota: Effects of early social contact

<div><p>As the sole reproductive female in a honey bee (<i>Apis mellifera</i>) colony, the queen’s health is critical to colony productivity and longevity. Beekeeping operations typically rely on the commercial mass production of queens for colony multiplication, which involves manipulating and isolating the queens by confining them in cages during early development. Using common queen-rearing techniques, this study shows that segregating newly eclosed queens from their worker attendants for 72 hours using queen protector cages has a significant impact on the total amount of gut bacteria carried by those queens compared to queens that have unrestricted access to attendants upon eclosion. Isolated virgin queens sampled immediately after isolation at 4 days post eclosure had significantly more bacteria and a less consistent microbiota composition than their non-isolated peers. Furthermore, this effect lasted into the mating life of queens, since mated queens that had been isolated after emergence and then sampled at 14 days post eclosure also had significantly more microbiota compared to non-isolated mated queens of the same age. The causes and potential impacts of this alteration are not clear and deserve further investigation. This study also verifies earlier findings that honey bee queens lack the core microbiome found within honey bee workers.</p></div

Queen grafting age significantly altered the chemical profile of mandibular gland contents.

<p>The chemical composition of mandibular gland extracts of honey bee queens raised from either first instar worker larvae (i.e., “high-quality” queens) or third instar worker larvae (i.e., “low-quality” queens) were analyzed using gas chromatography and mass spectrometry. Principal component analysis of the mandibular extracts from both queen types was done based on the relative proportion of each compound. The first principal component (PC1) explained 46.7% of the variation in mandibular gland composition. The second principal component (PC2) explained an additional 32.6% of the variation. There was a significant difference in the two-dimensional composite measure between high-quality queens (black squares) and low-quality queens (open circles). Solid and dashed ellipses signify 50% confidence intervals for PC1 and PC2 for high-quality queens and low-quality queens, respectively.</p

Bray-Curtis PCA plots of gut microbial community composition.

<p>PCA Plots were based on sampling OTUs at a depth of 1800 reads. a) Plot of all samples, coded by mating state. The yellow outer ellipsoid denotes the area occupied by workers and the inner ellipsoid shows dense clustering by 14-day-old workers. Significant differences were observed between workers and the mating states (mated vs. virgin) of queens (Adonis PERMANOVA, R² = 0.39; F_4,43 = 6.88; <i>p</i>< 0.001). b) Plot of virgin queens (4 days post eclosure) only. c) Plot of mated queens (14 days post eclosure) only. No significant differences were observed between isolated and non-isolated queens within the two age groups (<i>p</i>>0.05, Adonis PERMANOVA). The distances are based on an abundance-weighted Bray-Curtis analysis.</p