Search

Grooming behavior confers resistance to honey bees against Varroa destructor, being of interest to social immunity studies and breeding programs. The objective of this study was to characterize at the individual level the grooming behavior of mite-resistant (R) and susceptible (S) A. mellifera stocks from Argentina. Assays were performed in experimental arenas by applying two treatments to nurse bees: (1) placing a V. destructor mite on the bee’s thorax and (2) touching the bee with a paintbrush. Grooming reactions were recorded on bees from both stocks at the ages of 6, 10, and 14 days after emergence. R bees exhibited lower time of first response against the mite, performed more cleaning attempts, and used all their legs with a higher probability compared to S bees. The same pattern was evident when younger and older bees from the R stock were compared. The results demonstrate that bee age and genetic origin are critical factors of grooming behavior in honey bees. [ABSTRACT FROM AUTHOR]

A longitudinal study was carried out in order to evaluate Nosema spp. spore counts in two key moments of the year (late autumn and spring) in honeybee colonies from five eco-regions of Argentina. Three hundred and sixty colonies were randomly selected and the infestation level of Nosema spp. and Varroa destructor was assessed in autumn and spring of 2015. In addition, a questionnaire concerning all management practices applied in the colonies was answered by the beekeepers. Generalized linear mixed effect models were performed to determine the relationship between risk factors associated with Nosema spp. spore counts in each eco-region. Data were scanned to identify colonies cluster with a higher probability of achieving high values of Nosema spp. abundance for each sampling period. Spatial distribution of colonies with a higher risk of achieving high Nosema spp. abundance seems to be explained by geographical conditions associated to climatic conditions and some management practices implemented in each eco-region. [ABSTRACT FROM AUTHOR]

During a reproductive cycle, not all daughter mites of Varroa destructor mate and thus leave the brood cells as virgins. Here, we show that virgin mites are present within both the phoretic (10%) and reproductive (8%) mite population. Most (n = 29 of n = 33) of these encountered virgins laid unfertilized (= male) eggs, and some (n = 10) mated later on with their own son. These findings were verified by tests with artificially reared virgin mites. Obviously, mating is not a prerequisite for Varroa reproduction. However, due to the small number of reproductive cycles, the contribution of virgins to the Varroa population is regarded as low. This study also confirms conclusively that sex of V. destructor is determined via arrhenotokous parthenogenesis and not—as previously assumed—via pseudo-arrhenotoky. Furthermore, reproductive parameters of naturally invaded and artificially introduced Varroa females were compared, and artificial infestation was reconfirmed as a suitable method. [ABSTRACT FROM AUTHOR]

Varroa destructor, a parasitic mite of the western honey bee, Apis mellifera L., is a serious threat to colonies and beekeeping worldwide. Population genetics studies of the mite have provided information on two mitochondrial haplotypes infecting honey bee colonies, named K and J (after Korea and Japan, respectively, where they were originally identified). On the American continent, the K haplotype is much more prevalent, with the J haplotype only detected in some areas of Brazil. The aims of the present study were to assess the genetic diversity of V. destructor populations in the major beekeeping region of Argentina and to evaluate the presence of heteroplasmy at the nucleotide level. Phoretic mites were collected from managed A. mellifera colonies in ten localities, and four mitochondrial DNA (mtDNA) regions (COXI, ND4, ND4L, and ND5) were analyzed. Based on cytochrome oxidase subunit I (COXI) sequencing, exclusively the K haplotype of V. destructor was detected. Furthermore, two sub-haplotypes (KArg-N1 and KArg-N2) were identified from a variation in ND4 sequences and the frequency of these sub-haplotypes was found to significantly correlate with geographical latitude. The occurrence of site heteroplasmy was also evident for this gene. Therefore, ND4 appears to be a sensitive marker for detecting genetic variability in mite populations. Site heteroplasmy emerges as a phenomenon that could be relatively frequent in V. destructor. [ABSTRACT FROM AUTHOR]

Gluten-free muffins with squash seed flour (SSF) were developed for contribute to reduce nutritional deficiencies and improving the health of the celiac population. Physicochemical and sensory properties of muffins were evaluated. SSF was incorporated at two levels (10 and 20% w/w) in commercial gluten-free premix (control). Incorporation of SSF increased total dietary fiber content, protein and unsaturated fatty acids. The addition of SSF at 10% resulted in a muffin that did not differ significantly from the control muffin; and also that formulations with SSF at 20% caused an increase in the browning index. Browning was favored by the increase of SSF with higher levels of fiber content. Incorporation of SSF at 20% had a significant effect on the textural parameters (firmness and chewiness) of the muffin. Also, both formulations containing SSF showed a higher overall acceptability, particularly muffins with 20% of SSF that rendered the highest scores for sponginess, texture, taste and colour. [ABSTRACT FROM AUTHOR]