16 research outputs found

    Effect of larval exposure to <i>N</i>. <i>ceranae</i> on adult survival.

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    <p>Survival curves for the treatments are shown. A total of 238 individuals from four different colonies emerged as adults and were monitored in cages to measure survival.</p

    <i>Nosema</i> spores developing intracellularly in the midgut cells of bees at an early pre-pupal stage.

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    <p>(a-f) Images are shown at relative magnifications from 400-1400X, and scale bars correspond to 50 μm. The abbreviations refer to the following: lu = lumen (interior of midgut), bm = basement membrane, sp = <i>Nosema</i> spore, and n = midgut cell nucleus (relatively large blue-green ovoid structures shown in part b).</p

    Detailed spore count data for pre-pupae and adults. Mean spore counts ± 1 standard error are shown in Fig 2a and 2b.

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    <p>Detailed spore count data for pre-pupae and adults. Mean spore counts ± 1 standard error are shown in Fig <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0126330#pone.0126330.g002" target="_blank">2a</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0126330#pone.0126330.g002" target="_blank">2b</a>.</p

    <i>Nosema ceranae</i> spore counts in pre-pupae and adults.

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    <p>Effect of larval exposure to <i>N</i>. <i>ceranae</i> on midgut spore count in (a) pre-pupae and (b) adults upon death. (a) The average number of spores per bee midgut is shown. Error bars show standard errors. Different letters indicate significantly different treatments. (b) A higher percentage of bees fed <i>N</i>. <i>ceranae</i> as larvae were infected as (c) pre-pupae and (d) adults. These graphs show the percentage of bees with different levels of infection.</p

    The effect of imidacloprid on the percentage of bees choosing a safe over a dangerous feeder.

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    <p>Stars above bars indicate treatments in which bees significantly avoided the dangerous feeder (<i>P</i><0.05). Different shades of gray correspond to different imidacloprid concentrations. A dashed line shows the null hypothesis expectation: 50% of bees choose the safe feeder.</p

    Mean proportion of choices for the safe feeder over five trials.

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    <p>The different treatments are identified above each plot (1 = all choices for safe feeder). Different shades of gray correspond to different imidacloprid concentrations. Standard error bars are shown.</p

    Hornets are a threat.

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    <p>Hornets (scaled photos shown) are (A) attacked by <i>A. cerana</i> colonies and (B) attack <i>A. cerana</i> foraging on natural flowers. Standard error bars are shown. We indicate significant differences with different letters.</p

    How bee colonies allocate foraging among food sources with different food qualities and levels of predator danger.

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    <p>Sucrose-only feeders are shown as white bars, the butterfly control as a striped bar and the small (sm) and big hornet species as gray and black bars, respectively. Standard error bars are shown. In each graph, different letters indicate significant differences. We show the mean number of foragers at the feeder arrays in (A) experiment 1, (B) experiment 2, and (C) experiment 3 parts A and B. In experiment 3 part A, feeders had sucrose only (bars with thick lines). Part B used the same range of sucrose concentrations, but with the indicated hornet species at the higher sucrose concentrations.</p

    Effects of food quality and predator danger on individual feeding time.

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    <p>Bar patterns and standard error bars as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0075841#pone-0075841-g002" target="_blank">Fig. 2</a>. Different letters indicate significant differences. Mean feeding times at the feeder arrays in (A) experiment 1, (B) experiment 2, and (C) experiment 3 parts A and B. In experiment 3 part A, feeders had sucrose only (bars with thick lines). Part B used the same range of sucrose concentrations, but with the indicated hornet species at the higher sucrose concentrations.</p

    Effect of stop signals (SS) elicited by unknown natural causes, the small hornet, and the large hornet upon waggle dancing (dances performed by 51, 58, and 51 different bees from three colonies; the number of stop signals is shown in each plot).

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    The effect of naturally elicited stop signals was observed with bees waggle dancing for natural food sources. All other dances were from bees trained to a feeder, none of which directly experienced the predator. If stop signals had no effect upon waggle dancing, they would be uniformly distributed (shown by a dashed line). However, all distributions are significantly different from a uniform distribution (p large hornet forager) were significantly more inhibitory (p small hornet forager).</p
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