Sex-specific differences in pathogen susceptibility in honey bees (Apis mellifera).
Sex-related differences in susceptibility to pathogens are a common phenomenon in animals. In the eusocial Hymenoptera the two female castes, workers and queens, are diploid and males are haploid. The haploid susceptibility hypothesis predicts that haploid males are more susceptible to pathogen infections compared to females. Here we test this hypothesis using adult male (drone) and female (worker) honey bees (Apis mellifera), inoculated with the gut endoparasite Nosema ceranae and/or black queen cell virus (BQCV). These pathogens were chosen due to previously reported synergistic interactions between Nosema apis and BQCV. Our data do not support synergistic interactions between N. ceranae and BQCV and also suggest that BQCV has limited effect on both drone and worker health, regardless of the infection level. However, the data clearly show that, despite lower levels of N. ceranae spores in drones than in workers, Nosema-infected drones had both a higher mortality and a lower body mass than non-infected drones, across all treatment groups, while the mortality and body mass of worker bees were largely unaffected by N. ceranae infection, suggesting that drones are more susceptible to this pathogen than workers. In conclusion, the data reveal considerable sex-specific differences in pathogen susceptibility in honey bees and highlight the importance of ultimate measures for determining susceptibility, such as mortality and body quality, rather than mere infection levels.
Swiss Bee Research Centre, Research Station Agroscope Liebefeld-Posieux ALP-HARAS, Bern, Switzerland ; Institute of Bee Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
Gina
G
Retschnig
Swiss Bee Research Centre, Research Station Agroscope Liebefeld-Posieux ALP-HARAS, Bern, Switzerland ; Institute of Bee Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland ; Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada.
Geoffrey R
GR
Williams
Swiss Bee Research Centre, Research Station Agroscope Liebefeld-Posieux ALP-HARAS, Bern, Switzerland.
Marion M
MM
Mehmann
Swiss Bee Research Centre, Research Station Agroscope Liebefeld-Posieux ALP-HARAS, Bern, Switzerland ; Institute of Bee Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
Orlando
O
Yañez
Department of Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden.
Joachim R
JR
de Miranda
Swiss Bee Research Centre, Research Station Agroscope Liebefeld-Posieux ALP-HARAS, Bern, Switzerland ; Institute of Bee Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland ; Social Insect Research Group, Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa.
Peter
P
Neumann
D000818:Animals; D001516:Bees / Q000382:microbiology* / Q000821:virology*; D001835:Body Weight; D056629:Dicistroviridae / Q000502:physiology*; D005260:Female; D006608:Hierarchy, Social; D054884:Host-Pathogen Interactions; D008297:Male; D016818:Nosema / Q000502:physiology*; D012727:Sex Characteristics; D013045:Species Specificity; D013172:Spores, Fungal / Q000502:physiology; D016019:Survival Analysis