High sample throughput genotyping for estimating C-lineage introgression in the dark honeybee: an accurate and cost-effective SNP-based tool

The natural distribution of the honeybee (Apis mellifera L.) has been changed by humans in recent decades to such an extent that the formerly widest-spread European subspecies, Apis mellifera mellifera, is threatened by extinction through introgression from highly divergent commercial strains in large tracts of its range. Conservation efforts for A. m. mellifera are underway in multiple European countries requiring reliable and cost-efficient molecular tools to identify purebred colonies. Here, we developed four ancestry-informative SNP assays for high sample throughput genotyping using the iPLEX Mass Array system. Our customized assays were tested on DNA from individual and pooled, haploid and diploid honeybee samples extracted from different tissues using a diverse range of protocols. The assays had a high genotyping success rate and yielded accurate genotypes. Performance assessed against whole-genome data showed that individual assays behaved well, although the most accurate introgression estimates were obtained for the four assays combined (117 SNPs). The best compromise between accuracy and genotyping costs was achieved when combining two assays (62 SNPs). We provide a ready-to-use cost-effective tool for accurate molecular identification and estimation oinfo:eu-repo/semantics/publishedVersio

Behavioral genomics of honeybee foraging and nest defense

The honeybee has been the most important insect species for study of social behavior. The recently released draft genomic sequence for the bee will accelerate honeybee behavioral genetics. Although we lack sufficient tools to manipulate this genome easily, quantitative trait loci (QTLs) that influence natural variation in behavior have been identified and tested for their effects on correlated behavioral traits. We review what is known about the genetics and physiology of two behavioral traits in honeybees, foraging specialization (pollen versus nectar), and defensive behavior, and present evidence that map-based cloning of genes is more feasible in the bee than in other metazoans. We also present bioinformatic analyses of candidate genes within QTL confidence intervals (CIs). The high recombination rate of the bee made it possible to narrow the search to regions containing only 17–61 predicted peptides for each QTL, although CIs covered large genetic distances. Knowledge of correlated behavioral traits, comparative bioinformatics, and expression assays facilitated evaluation of candidate genes. An overrepresentation of genes involved in ovarian development and insulin-like signaling components within pollen foraging QTL regions suggests that an ancestral reproductive gene network was co-opted during the evolution of foraging specialization. The major QTL influencing defensive/aggressive behavior contains orthologs of genes involved in central nervous system activity and neurogenesis. Candidates at the other two defensive-behavior QTLs include modulators of sensory signaling (Am5HT(7) serotonin receptor, AmArr4 arrestin, and GABA-B-R1 receptor). These studies are the first step in linking natural variation in honeybee social behavior to the identification of underlying genes

Synergistic Parasite-Pathogen Interactions Mediated by Host Immunity Can Drive the Collapse of Honeybee Colonies

The health of the honeybee and, indirectly, global crop production are threatened by several biotic and abiotic factors, which play a poorly defined role in the induction of widespread colony losses. Recent descriptive studies suggest that colony losses are often related to the interaction between pathogens and other stress factors, including parasites. Through an integrated analysis of the population and molecular changes associated with the collapse of honeybee colonies infested by the parasitic mite Varroa destructor, we show that this parasite can de-stabilise the within-host dynamics of Deformed wing virus (DWV), transforming a cryptic and vertically transmitted virus into a rapidly replicating killer, which attains lethal levels late in the season. The de-stabilisation of DWV infection is associated with an immunosuppression syndrome, characterized by a strong down-regulation of the transcription factor NF-κB. The centrality of NF-κB in host responses to a range of environmental challenges suggests that this transcription factor can act as a common currency underlying colony collapse that may be triggered by different causes. Our results offer an integrated account for the multifactorial origin of honeybee losses and a new framework for assessing, and possibly mitigating, the impact of environmental challenges on honeybee health

Evaluation of appendicitis risk prediction models in adults with suspected appendicitis

Background Appendicitis is the most common general surgical emergency worldwide, but its diagnosis remains challenging. The aim of this study was to determine whether existing risk prediction models can reliably identify patients presenting to hospital in the UK with acute right iliac fossa (RIF) pain who are at low risk of appendicitis. Methods A systematic search was completed to identify all existing appendicitis risk prediction models. Models were validated using UK data from an international prospective cohort study that captured consecutive patients aged 16–45 years presenting to hospital with acute RIF in March to June 2017. The main outcome was best achievable model specificity (proportion of patients who did not have appendicitis correctly classified as low risk) whilst maintaining a failure rate below 5 per cent (proportion of patients identified as low risk who actually had appendicitis). Results Some 5345 patients across 154 UK hospitals were identified, of which two‐thirds (3613 of 5345, 67·6 per cent) were women. Women were more than twice as likely to undergo surgery with removal of a histologically normal appendix (272 of 964, 28·2 per cent) than men (120 of 993, 12·1 per cent) (relative risk 2·33, 95 per cent c.i. 1·92 to 2·84; P < 0·001). Of 15 validated risk prediction models, the Adult Appendicitis Score performed best (cut‐off score 8 or less, specificity 63·1 per cent, failure rate 3·7 per cent). The Appendicitis Inflammatory Response Score performed best for men (cut‐off score 2 or less, specificity 24·7 per cent, failure rate 2·4 per cent). Conclusion Women in the UK had a disproportionate risk of admission without surgical intervention and had high rates of normal appendicectomy. Risk prediction models to support shared decision‐making by identifying adults in the UK at low risk of appendicitis were identified

Relative effect of four characteristics that restrain the population growth of the mite Varroa destructor in honey bee (Apis mellifera) colonies

This study was conducted to determine the existence of phenotypic and genotypic variation in the ability of honey bee colonies to restrain the population growth of the mite Varroa destructor Anderson and Trueman, and to asses the relative effect of four characteristics that may confer tolerance to honey bees toward the mite. Fifty-eight colonies infested with an equal number of mites were sampled monthly during six months to determine their levels of infestation on adult bees and in worker brood. At the end of this period, 16 colonies were selected to study the effect of grooming behavior, hygienic behavior, brood attractiveness, and host-induced non-reproduction. The infestation-levels in adult bees varied significantly between colonies (range: 6.6-44.7% ), but no differences were found in the brood infestation levels. The variation between colonies was partially genetic in origin. Grooming behavior explained most of the variation ($r^2 = 0.38$). Negative correlations were found between the mite population growth and both the total number of mites and the number of injured mites collected from the bottom-boards ($r = -0.65$ and $r = -0.76$, respectively). Differences were found for hygienic behavior but the effect of this mechanism was not clear. No differences were found among colonies for brood attractiveness, or for the effect of the brood on the mite's reproduction

Susceptibility of European and Africanized honey bees (Apis mellifera L.) to Varroa jacobsoni Oud. in Mexico

The knowledge generated from several studies conducted in Mexico on the susceptibility of European and Africanized honey bees to Varroa jacobsoni is reviewed and compared with the situation in Brazil. There is evidence of genotypic variation for mite population growth, and for tolerance to the mite in honey bee colonies located in Mexico. However, Mexican honey bees seem to be relatively less tolerant to the parasite than bees in Brazil. The main difference is that mite fertility rates in Mexico are higher than those reported from Brazil. Hypotheses for why the situation is different in Mexico than in Brazil are discussed. © Inra/DIB/AGIB/Elsevier, Pari

Efecto de tres dietas energético-proteicas en la población y producción de miel de colonias de abejas melíferas (Apis mellifera)

Abstract The objective of this study was to compare the population, weight and honey production of honey bee (Apis mellifera) colonies fed with three different energy-protein diets based on a feed supplement made with brewer's yeast and pollen, in combination with 55% high fructose corn syrup (JMAF), or sucrose syrup (JA), or inverted sucrose syrup (JAI). Ninety colonies equalized in terms of population size, food stores and queen origin and age were used. All colonies were fed the protein supplement, but 30 of them were fed JMAF, 30 JA and 30 JAI. The adult bee population, capped brood area, weight and honey production of the colonies was determined at 27, 49 and 76 days after they were established and fed with the diets. Colonies fed JMAF were significantly heavier than those fed JA and JAI, between which there were no differences. JMAF-fed colonies produced significantly more honey (35.8 ± 3.35 kg) than those fed JA (28.2 ± 2.65) and JAI (24.8 ± 2.70 kg), between which there were no differences. These results suggest that the use of JMAF in combination with a protein supplement to stimulate honey bee colonies represents a more efficient option than the use of JAI and JAI with protein supplementation.Resumen El objetivo del presente trabajo fue comparar el desarrollo poblacional, peso y producción de miel en colonias de abejas melíferas (Apis mellifera) alimentadas con tres dietas energético-proteicas a base de un suplemento elaborado con levadura de cerveza y polen, en combinación con jarabe de maíz de alta fructosa al 55% (JMAF), jarabe de sacarosa (JA), o jarabe de sacarosa invertido (JAI). Se utilizaron 90 colonias homogeneizadas en cuanto a tamaño poblacional, reservas de alimento y origen y edad de las reinas, todas alimentadas con el suplemento proteico, pero además, 30 de ellas recibieron JMAF, 30 JA y 30 JAI. La población de abejas adultas, área de cría operculada, peso y producción de miel de las colonias se determinó a los 27, 49 y 76 días después de haber sido establecidas y alimentadas con las dietas. Las colonias alimentadas con JMAF fueron significativamente más pesadas que las alimentadas con JA y JAI entre las cuales no hubo diferencias. Las colonias alimentadas con JMAF produjeron significativamente más miel (35.8±3.35 kg) que las alimentadas con JA (28.2±2.65) y con JAI (24.8±2.70 kg), entre las cuales no hubo diferencias. Los resultados sugieren que el uso de JMAF en combinación con un suplemento proteico en la alimentación artificial de las colonias de abejas melíferas estimula su crecimiento poblacional y la producción de miel, representando una opción más eficiente en comparación con las alimentadas con el suplemento proteico más el JA y JAI

Confirmation of QTL effects and evidence of genetic dominance of honey bee defensive behavior: Results of colony and individual behavioral assays

The stinging and guarding components of the defensive behavior of European, Africanized, hybrid, and backcross honeybees (Apis mellifera L.) were compared and analyzed at both colony and individual levels. Hybrid and Africanized backcross colonies stung as many times as Africanized ones. European backcross colonies stung more than European bees but not as many times as Africanized or Africanized backcross colonies. The degree of dominance for the number of times that worker bees stung a leather patch was estimated to be 84.3%, 200.8%, and 145.8% for hybrid, backcross European, and backcross Africanized colonies, respectively. Additionally, both guards at the colony entrance and fast-stinging workers of one European backcross colony had a significantly higher frequency of an Africanized DNA marker allele, located near “sting1,” a QTL previously implicated in stinging behavior at the colony level. However, guards and faststinging bees from a backcross to the Africanized parental colony did not differ from control bees in their frequency for the Africanized and European markers, as would be expected if large genetic dominance effects for sting1 exist. These results support the hypothesis that genetic dominance influences the defensive behavior of honeybees and confirm the effect of sting1 on the defensiveness of individual worker bees. KEY WORDS: Apis mellifera; defensive behavior; Africanized honeybees; genetic dominance; QTL