Principal component analysis of lipid profile for honey bees and their hive components.

<p>Score plot shows variation in PLFA-FAME profiles by hive components. Lines drawn delineate sample aggregates. Inlay displays one propolis sample that skewed the plot. Main plot is redrawn without that data point. When produced by sample year, individual hive or location, no clustering is readily apparent.</p

Unique Honey Bee (<i>Apis mellifera</i>) Hive Component-Based Communities as Detected by a Hybrid of Phospholipid Fatty-Acid and Fatty-Acid Methyl Ester Analyses

<div><p>Microbial communities (microbiomes) are associated with almost all metazoans, including the honey bee <i>Apis mellifera</i>. Honey bees are social insects, maintaining complex hive systems composed of a variety of integral components including bees, comb, propolis, honey, and stored pollen. Given that the different components within hives can be physically separated and are nutritionally variable, we hypothesize that unique microbial communities may occur within the different microenvironments of honey bee colonies. To explore this hypothesis and to provide further insights into the microbiome of honey bees, we use a hybrid of fatty acid methyl ester (FAME) and phospholipid-derived fatty acid (PLFA) analysis to produce broad, lipid-based microbial community profiles of stored pollen, adults, pupae, honey, empty comb, and propolis for 11 honey bee hives. Averaging component lipid profiles by hive, we show that, in decreasing order, lipid markers representing fungi, Gram-negative bacteria, and Gram-positive bacteria have the highest relative abundances within honey bee colonies. Our lipid profiles reveal the presence of viable microbial communities in each of the six hive components sampled, with overall microbial community richness varying from lowest to highest in honey, comb, pupae, pollen, adults and propolis, respectively. Finally, microbial community lipid profiles were more similar when compared by component than by hive, location, or sampling year. Specifically, we found that individual hive components typically exhibited several dominant lipids and that these dominant lipids differ between components. Principal component and two-way clustering analyses both support significant grouping of lipids by hive component. Our findings indicate that in addition to the microbial communities present in individual workers, honey bee hives have resident microbial communities associated with different colony components.</p></div

Set of Detected Lipids and Their Indications.

<p>Widespread—lipid is found within many domains of life. Blank—lipid was not described as indicating a specific group in referenced reports. Abbreviations: Gram-negative (Gm-); Gram-positive (Gm+); γ-Proteobacteria (γ-proteo EV = <i>Enterobacter/Vibrio</i>); <i>Bacillus-Clostridium</i> group (BC); Actinobacteria (Act); Anaerobes (An); Saprotrophic Fungi (SP); Arbuscular mycorrhizal fungi (AMF); Ectomycorrhizal fungi (Ecto).</p><p>Set of Detected Lipids and Their Indications.</p

Average abundance of the most common lipids within honey bee colonies.

<p>Bar graph representing the average biomass of the most common lipids on a whole hive basis, generated by combining the individual hive components. Presented are those lipids that represent more than 1%. Error bars represent standard error of the mean. Abbreviations: Gram-negative (Gm-); Gram-positive (Gm+); γ-Proteobacteria (γ-proteo EV = <i>Enterobacter/Vibrio</i>); <i>Bacillus-Clostridium</i> group (BC); Saprotrophic Fungi (SP); Ectomycorrhizal fungi (Ecto).</p

P-Values from Tukey-Kramer HSD Pairwise Comparisons of Lipid Profiles by Year.

<p>*—Comparison Not Valid;</p><p>NS—Not Significant</p><p>P-Values from Tukey-Kramer HSD Pairwise Comparisons of Lipid Profiles by Year.</p

Lipid-based microbial community profile for honey bees and their hive components.

<p>Relative abundance of Actinobacteria, Gram-positive, Gram-negative, general bacteria, and fungi associated with honey bees and the different components of honey bee colonies.</p

Rarefaction and lipid accumulation curves for honey bees and their hive components.

<p><b>A.)</b> Observed and estimated curves resulting from community analyses of adults, honey, and pollen using <i>Mao Tau</i> and <i>Chao2</i> methods. <b>B.)</b> Observed and estimated curves from comb, pupae, and propolis community analyses. Dashed lines represent corresponding confidence intervals.</p

P-values from Tukey-Kramer HSD Pairwise Comparisons of Total Number of Lipids Detected in Each Component.

<p>NS—Not Significant</p><p>P-values from Tukey-Kramer HSD Pairwise Comparisons of Total Number of Lipids Detected in Each Component.</p

Lipid richness for honey bees and their hive components.

<p>Average number of individual lipids detected from each hive component. Error bars represent standard error of the mean. Letters represent Tukey-Kramer HSD pairwise comparisons, with those groups not possessing overlap in letters being significantly different. Those groups sharing letters do not significantly differ.</p

P-Values from Significant Tukey-Kramer HSD Pairwise Comparisons of Lipid Profiles By Component.

<p>*—Comparison Not Valid;</p><p>NS—Not Significant</p><p>P-Values from Significant Tukey-Kramer HSD Pairwise Comparisons of Lipid Profiles By Component.</p