Shift in virus composition in honeybees (Apis mellifera) following worldwide invasion by the parasitic mite and virus vector Varroa destructor

Invasive vectors can induce dramatic changes in disease epidemiology. While viral emergence following geographical range expansion of a vector is well known, the influence a vector can have at the level of the host's pathobiome is less well understood. Taking advantage of the formerly heterogeneous spatial distribution of the ectoparasitic mite Varroa destructor that acts as potent virus vector among honeybees Apis mellifera, we investigated the impact of its recent global spread on the viral community of honeybees in a retrospective study of historical samples. We hypothesized that the vector has had an effect on the epidemiology of several bee viruses, potentially altering their transmissibility and/or virulence, and consequently their prevalence, abundance, or both. To test this, we quantified the prevalence and loads of 14 viruses from honeybee samples collected in mite-free and mite-infested populations in four independent geographical regions. The presence of the mite dramatically increased the prevalence and load of deformed wing virus, a cause of unsustainably high colony losses. In addition, several other viruses became more prevalent or were found at higher load in mite-infested areas, including viruses not known to be actively varroa-transmitted, but which may increase opportunistically in varroa-parasitized bees.

Liquid Side Streams from Mussel and Herring Processing as Sources of Potential Income

The seafood industry generates significant amounts of process waters which can generate value upon recovery of their nutrients. Process waters from the herring marination chain and cooking of mussels were here characterized in terms of crude composition, volatile compounds, and nutritional and potentially toxic elements. Protein and total fatty acid contents of herring refrigerated sea water (RSW) reached 3 and 0.14 g/L, respectively, while herring presalting brine (13%) reached 16.3 g/L protein and 0.77 g/L total fatty acid. Among three herring marination brines vinegar brine (VMB), spice brine (SPB), and salt brine (SMB), SPB reached the highest protein (39 g/L) and fatty acids (3.0 g/L), whereas SMB and VMB at the most had 14 and 21 g protein/L, respectively, and 0.6 and 9.9 g fatty acids/L, respectively. Essential amino acid (EAA) in marination brines accounted for up to 59% of total amino acid (TAA). From mussel processing, cooking juice had more protein (14-23 g/L) than the rest of the process waters, and in all water types, EAA reached up to 42% of TAA. For all process waters, the most abundant nutritional elements were Na, K, P, Ca, and Se. The content of all potentially toxic elements was mostly below LOD, except for As which ranged from 0.07 to 1.07 mg/kg among all tested waters. Our findings shed light on liquid seafood side streams as untapped resources of nutrients which can be valorized into food/feed products.

Variable pollen viability and effects of pollen load size on components of seed set in cultivars and feral populations of oilseed rape

Pollination success is important for crop yield, but may be cultivar dependent. Less is known about which floral traits influence pollination success. Floral traits, e.g. traits related to attraction and reward, can also contribute to gene flow via pollen, the latter being of particular importance in oilseed rape (Brassica napus) where gene flow occurs between plants of crop, volunteer and feral origin as well as related taxa. We investigated the relationship between pollen load size and seed set in winter oilseed rape. We compared variability in pollen-viability traits, flower production (flowers from the main raceme times number of branches) and seed number and weight per siliqua among cultivars and feral populations (growing outside of agricultural fields) under controlled conditions. Both seed number and weight were saturated at relatively low pollen loads in the tested cultivar. Pollen viability and estimated flower production differed among cultivars, indicating that these traits could contribute to yield variability. Seed weight per siliqua, but not pollen traits or flower production, was lower in ferals compared to cultivars. Thus, while the probability of establishment may be reduced in ferals (due to lower seed weight per siliqua) this will not necessarily impact their contribution to gene flow via pollen. In oilseed rape a relatively low pollen load may be sufficient for full seed set in some cultivars, suggesting less dependence on insect pollination for high yield than generally expected. Our results also showed that previously less investigated floral traits, such as pollen viability, pollen tube growth rate and flower number, can differ between cultivars. Studies of these traits may provide targets for increasing crop yield and provide general knowledge about gene flow between cultivated, feral and related wild populations.