A New Threat to Honey Bees, the Parasitic Phorid Fly Apocephalus borealis

Honey bee colonies are subject to numerous pathogens and parasites. Interaction among multiple pathogens and parasites is the proposed cause for Colony Collapse Disorder (CCD), a syndrome characterized by worker bees abandoning their hive. Here we provide the first documentation that the phorid fly Apocephalus borealis, previously known to parasitize bumble bees, also infects and eventually kills honey bees and may pose an emerging threat to North American apiculture. Parasitized honey bees show hive abandonment behavior, leaving their hives at night and dying shortly thereafter. On average, seven days later up to 13 phorid larvae emerge from each dead bee and pupate away from the bee. Using DNA barcoding, we confirmed that phorids that emerged from honey bees and bumble bees were the same species. Microarray analyses of honey bees from infected hives revealed that these bees are often infected with deformed wing virus and Nosema ceranae. Larvae and adult phorids also tested positive for these pathogens, implicating the fly as a potential vector or reservoir of these honey bee pathogens. Phorid parasitism may affect hive viability since 77% of sites sampled in the San Francisco Bay Area were infected by the fly and microarray analyses detected phorids in commercial hives in South Dakota and California's Central Valley. Understanding details of phorid infection may shed light on similar hive abandonment behaviors seen in CCD

Towards the modular decomposition of the metabolic network

International audienceModular systems emerged in biology through the natural selection and evolution, even at the scale of the cell with the cellular processes which perform elementary and specialized tasks. However, the existence of modules is questionable when the regulatory networks of the cell are superimposed, in particular for the metabolic network. In this chapter, a theoretical framework is introduced allowing to break down the metabolic network into elementary modules in steady-state. The modular decomposition confers to the whole system good systemic and control properties, like the decoupling of the steady-state regime with respect to co-metabolites or co-factors. Biological configurations, and their impact on module properties, are deeply discussed. In particular, irreversible enzymes are critical in the module definition. Moreover, through the proposed framework, the dynamics of module components can be qualitatively predicted and used to analyze biological datasets