Inheritance of reduced Varroa mite reproductive success in reciprocal crosses of mite-resistant and mite-susceptible honey bees (Apis mellifera)

International audienceAbstractA well-documented population of honey bees on Gotland, Sweden is resistant to Varroa destructor mites and is able in some way to reduce the mite’s reproductive success. The aim of this study was to determine the genetic and maternal contribution to the inheritance of the reduced mite reproductive success trait in this population. Four genotypic groups of colonies were established by crossing the mite-resistant population of Gotland with a mite-susceptible population in Uppsala, Sweden, through artificial insemination of reared queens with drone semen. All the colonies in groups with a genetic origin from the resistant population expressed reduced mite reproductive success regardless if the genetic origin was maternal, paternal or both, and no statistical differences were observed between the reciprocal crosses. These results strongly imply a dominant genetic component to the trait’s inheritance, as opposed to maternal effects or epigenetic mechanisms, and that the trait can be easily produced through selective breeding using the mite-resistant Gotland bee stock

Natural Varroa mite-surviving Apis mellifera honeybee populations

International audienceAbstractThe Varroa destructor mite is the largest threat to apiculture worldwide and has been responsible for devastating losses of wild honeybee populations in Europe and North America. However, Varroa mite-resistant populations of A. mellifera honeybees have been reported and documented around the world with a variety of explanations for their long-term survival with uncontrolled mite infestation. This review synthesizes the work on naturally occurring survival to Varroa mites and discusses what these honeybee populations can signify for apiculture

Host-parasite adaptations and interactions between honey bees, Varroa mites and viruses

The ectoparasitic mite, Varroa destructor, has become the largest threat to apiculture and honey bee health world-wide. Since it was introduced to the new host species, the European honey bee (Apis mellifera), it has been responsible for the near complete eradication of wild and feral honey bee populations in Europe and North America. Currently, the apicultural industry depends heavily on chemical Varroa control treatments to keep managed colonies alive. Without such control the mite populations in the colony will grow exponentially and the honey bee colony will succumb to the development of overt virus infections that are vectored by the mite typically within three years. Two unique sub-populations of European honey bees (on Gotland, Sweden and in Avignon, France) have adapted to survive for extended periods (over ten years) without the use of mite control treatments. This has been achieved through a natural selection process with unmanaged mite infestation levels enforcing a strong selection pressure. This thesis reveals that the adaptation acquired by these honey bee populations mainly involve reducing the reproductive success of the parasite, that the different populations may have evolved different strategies to do so, and that this mite-resistant trait is genetically inherited. In addition, results of this thesis demonstrate that chemical mite control treatments used by beekeepers to inhibit the mite population growth within a colony can actually worsen bee health by temporarily increasing the bee's susceptibility to virus infection. The results of this thesis highlight the impact that apicultural practices otherwise have on host-parasite interactions and the development of disease in this system. Possible solutions to the threat of Varroa are discussed such as the potential to breed for mite-resistant honey bees, which may offer a sustainable long-term solution, and the need for better general beekeeping techniques that reduce the use of chemical treatments and inhibit the spread of disease

a study of adult recreation in East Boston

Thesis (M.S.)--Boston Universit

Service-learning and leadership life skills: an experimental study

This study examined the effect of service activities on the development of leadership life skills in youth and if having a reflection component as part of the activity makes a difference. Additionally, the study examined the impact of selected demographics including age, gender, type of service completed monthly and 4-H membership on the development of leadership life skills. Participants in the study were from two samples. One group represented the El Paso National Youth Service Day, the other represented the District 11 4-H Leadership Lab in Brenham, Texas. Participants were randomly assigned to a control (no reflection) or treatment (with reflection) group. Youth participants self rated their leadership life skills using a 33-question post-test only questionnaire. Demographics were reported in nine additional questions. The major findings of the study are as follows: 1) Overall, the participants reported their perceived leadership life skills to be high in four of the five subscales; 2) The inclusion of a reflection component did not significantly affect perceived leadership life skills; 3) Type of service, whether direct or indirect, had a significant impact on perceived leadership life skills; 4) 4-H membership had a significant impact on the Personal Leadership Development subscale

SLU:s verksamhet med bin

Under 2014/15 var vi sammanlagt sju personer i den grupp på SLU som arbetar med olika aspekter på hälsa och sjukdomar hos honungsbin. Gruppen utökades under sommaren 2014 med två nya forskarstuderande/doktorander; Sepideh Lamei som ska studera mjölksyrabakteriers betydelse för bins hälsa, och Srinivas Thaduri som ska studera sammansättningen av mikroorganismer hos den gotländska population av bin som överlevt och klarar sig utan behandling mot varroakvalstret (de så kallade Bondbina). En kortfattad beskrivning av deras respektive projekt kan ni läsa om längre ned i texten

Reproductive success of the parasitic mite (Varroa destructor) is lower in honeybee colonies that target infested cells with recapping

Cell recapping is a behavioural trait of honeybees (Apis mellifera) where cells with developing pupae are uncapped, inspected, and then recapped, without removing the pupae. The ectoparasitic mite Varroa destructor, unarguably the most destructive pest in apiculture world-wide, invades the cells of developing pupae to feed and reproduce. Honeybees that target mite infested cells with this behaviour may disrupt the reproductive cycle of the mite. Hence, cell recapping has been associated with colony-level declines in mite reproduction. In this study we compared the colony-level efficacy of cell recapping (how often infested cells are recapped) to the average mite fecundity in A. mellifera. Our study populations, known to be adapted to V. destructor, were from Avignon, France, Gotland, Sweden, and Oslo, Norway, and were compared to geographically similar, treated control colonies. The results show that colonies with a higher recapping efficacy also have a lower average mite reproductive success. This pattern was likely driven by the adapted populations as they had the largest proportion of highly-targeted cell recapping. The consistent presence of this trait in mite-resistant and mite-susceptible colonies with varying degrees of expression may make it a good proxy trait for selective breeding on a large scale

Do published guidelines for evaluation of Irritable Bowel Syndrome reflect practice?

BACKGROUND: The only US guidelines listed in the National Guideline Warehouse for the diagnosis of Irritable Bowel Syndrome (IBS) are the expert opinion guidelines published by The American Gastroenterology Association. Although the listed target audience of these guidelines includes family physicians and general internists, the care recommended in the guidelines has not been compared to actual primary care practice. This study was designed to compare expert opinion guidelines with the actual primary care provided and to assess outcomes in the 3 years following the IBS diagnosis. METHODS: This is a retrospective medical record review study using a random sample of incident IBS cases from all Olmsted County, Minnesota providers diagnosed between January 1, 1993 and December 31, 1995. Data was collected on all care and testing provided to the subjects as well as 3-year outcomes related to the IBS diagnosis. RESULTS: Of the 149 IBS patients, 99 were women and the mean age was 47.6 years. No patient had all of the diagnostic tests recommended in the guidelines. 42% had the basic blood tests of CBC and a chemistry panel. Sedimentation rate (2%) and serum thyroxine level (3%) were uncommon. Colon imaging studies were done in 41% including 74% of those over the age of 50. In the 3 years following the diagnosis, only one person had a change in diagnosis and no diagnoses of gastro-intestinal malignancies were made in the cohort. CONCLUSIONS: Primary care practice based diagnostic evaluations for IBS differ significantly from the specialty expert opinion-based guidelines. Implementation of the specialty guidelines in primary care practice would increase utilization with apparent limited improvement in diagnostic outcomes

Honey bee survival mechanisms against the parasite Varroa destructor: a systematic review of phenotypic and genomic research efforts

The ectoparasitic mite Varroa destructor is the most significant pathological threat to the western honey bee, Apis mellifera, leading to the death of most colonies if left untreated. An alternative approach to chemical treatments is to selectively enhance heritable honey bee traits of resistance or tolerance to the mite through breeding programs, or select for naturally surviving untreated colonies. We conducted a literature review of all studies documenting traits of A. mellifera populations either selectively bred or naturally selected for resistance and tolerance to mite parasitism. This allowed us to conduct an analysis of the diversity, distribution and importance of the traits in different honey bee populations that can survive V. destructor globally. In a second analysis, we investigated the genetic bases of these different phenotypes by comparing 'omics studies (genomics, transcriptomics, and proteomics) of A. mellifera resistance and tolerance to the parasite. Altogether, this review provides a detailed overview of the current state of the research projects and breeding efforts against the most devastating parasite of A. mellifera. By highlighting the most promising traits of Varroa-surviving bees and our current knowledge on their genetic bases, this work will help direct future research efforts and selection programs to control this pest. Additionally, by comparing the diverse populations of honey bees that exhibit those traits, this review highlights the consequences of anthropogenic and natural selection in the interactions between hosts and parasites. (C) 2020 The Authors. Published by Elsevier Ltd on behalf of Australian Society for Parasitology