Better explicating the strengths and shortcomings of these models will help refine projections and improve transparency in the years ahead.
Image credit: Witsawat.S.
Edited by David L. Denlinger, Ohio State University, Columbus, OH, and approved January 26, 2016 (received for review December 1, 2015)
Article Figures & SI
Figures
- Fig. 1.
Immunocompetence of honey bee larvae as affected by DWV infection. (A) Nylon threads at 24 h after implantation into the body of fifth instar honey bee larvae with increasing DWV infection levels. (B) Level of melanization of a nylon thread implant in honey bee larvae with different levels of viral infection, measured as number of DWV genome copies (ρ = −0.656, n = 28, P < 0.001). (C) Level of encapsulation of a nylon thread implant in honey bee larvae with different levels of viral infection, measured as number of DWV genome copies (ρ = −0.390, n = 28, P = 0.040).
- Fig. 2.
Amel\102 transcriptional profile and regulation. (A) Amel\102 transcription profile in honey bee larval tissues (adjusted H = 11.52, df = 2, P = 0.003). (B) Transcription level of dorsal-1A in honey bees maintained for different time intervals on a sucrose/protein solution containing a dsRNA targeting this gene (dsRNA dorsal) or dsRNA GFP as a control. (C) Transcription level of Amel\102 as affected by silencing of dorsal-1A. The error bars indicate the SD of the mean. The significant drop in dorsal-1A transcription (H = 11.57, df = 1, P < 0.001) was associated with a significant transcriptional down-regulation of Amel\102 (H = 14.29, df = 1, P < 0.001).
- Fig. S1.
(A) Alignment of H. virescens, S. littoralis, D. melanogaster, and A. mellifera 102 protein sequences. Black and gray shadings indicate identity and high conservation of amino acids, respectively. (B) Predicted secondary structure and conserved domains of Amel\102 protein.
- Fig. 3.
Gene expression in honey bee larvae as affected by DWV infection. (A–C) Effect of DWV infection level on transcription of (A) Amel\102 (ρ = −0.575, n = 28, P = 0.001), (B) apidaecin (ρ = −0.636, n = 28, P < 0.001), and (C) Amel\LRR (ρ = 0.511, n = 28, P = 0.005). (D) Amel\102 transcription as affected by DWV infection (F = 66.37, df = 1, P < 0.001) and feeding activity by the Varroa mite (F = 2.74, df = 1, P = not significant; interaction: F = 1.69, df = 1, P = not significant). Error bars indicate SD.
- Fig. S2.
Transcription level of apidaecin as affected by silencing of dorsal-1A. Error bars indicate the SD of the mean (H = 14.29, df = 1, P < 0.001).
- Fig. 4.
Viral infection and mite reproduction. (A) Proportion of reproducing Varroa mites (i.e., fertility) on honey bees with different levels of DWV infection. The equation of the curve describing the observed trend and the correlation coefficient are y = −0.0122x2 + 0.1979x – 0.2437 and R2 = 0.868 (df = 3, P = 0.048). The black squares represent the values expected under this model. (B) Mite fertility on honey bees with deformed or normal wings at eclosion (χ2 = 4.64, df = 1, P = 0.031). Error bars indicate the 95% confidence limits of the proportions.
- Fig. S3.
V. destructor adult on a honey bee larva kept in the gelatin capsule used for in vitro experiments on mite reproduction.
- Fig. S4.
A honey bee with deformed wings obtained from a larva artificially infested with a Varroa mite, which reproduced within the rearing cell. The mother mite and an immature offspring are seen on the abdomen.
- Fig. S5.
Fecundity of mites infesting honey bees showing normal and deformed wings at eclosion (A) and the distribution of mites according to the number of offspring (B and C). (B) Mites kept on bees with normal wings on eclosion. (C) Mites on bees with deformed wings. Error bars indicate the SD. The hyphens in B and C indicate the proportion expected according to the Poisson distribution. The significant deviation observed in both normal-winged bees and deformed-winged bees (χ2 = 18.02, df = 1, P < 0.001 and χ2 = 30.32, df = 2, P < 0.001, respectively) suggests that the first and subsequent ovipositions are not independent events, and that reproduction needs to be triggered once for continuing as long as conditions are suitable.
Tables
Analysis Name Sequence, bp Fragment, bp RACE 5′ Amel\102 GSP ATGGTTTCATTTATATCCTCGA (22) 473 Amel\102 NESTED GSP GATATAATGTTATATGTCATGC (22) RACE 3′ Amel\102 GSP CCTCGAAGTAAAGGAATAACTG (22) 444 Amel\102 NESTED GSP GAACATGTATTTATAGGAGAAAG (23) qRT-PCR DWV, forward GCGCTTAGTGGAGGAAATGAA (21) 69 DWV, reverse GCACCTACGCGATGTAAATCTG (22) qRT-PCR Amel\102, forward CAACTCCAGAATTGGAAATAGCA (23) 160 Amel\102, reverse TTTGCAATAGGAAAAGCAGTTG (22) qRT-PCR Actin, forward GATTTGTATGCCAACACTGTCCTT (24) 69 Actin, reverse TTGCATTCTATCTGCGATTCCA (22) qRT-PCR Dorsal, forward TCGGATGGTGCTACGAGCGA 153 Dorsal, reverse AGCATGCTTCTCAGCTTCTGCCT qRT-PCR Apidaecin, forward TTTTGCCTTAGCAATTCTTGTTG 81 Apidaecin, reverse GAAGGTCGAGTAGGCGGATCT qRT-PCR Amel\LRR, forward CTTGGTGAAGGCCTTGATG 87 Amel\LRR, reverse ATGCAAAGAGCTATCATCA
Data supplements
Supporting Information
A mutualistic symbiosis undermining bee health
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- Biological Sciences
- Agricultural Sciences
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