The ectoparasitic mite, Varroa destructor is one of the most destructive pests of the honeybee (Apis mellifera) leading to the collapse honey bee colony in many regions of the world. RNA interference (RNAi) is a novel approach recently proposed for insect pest control. However, the efficiency of RNAi in insects is low due to the lack of effective delivery methods for dsRNA and sensitivity to nuclease degradation. Therefore, the success of RNAi technology largely depends on the stability of dsRNA. To explore the possibility of using RNAi to control varroa mite, we determined the effects of dsRNA targeting a subunit of the cytoplasmic coatomer protein complex B2, D, and E subunits on target gene expression for varroa mite. We observe that dsRNA ingested by bees is transferred to the varroa mite, resulting in knockdown of COPB2 expression. Furthermore, we demonstrate that chitosan nanoparticles-dsRNA complexes were more stable for 7 days in honeybee tissue fluids. The dsRNA-conjugated with chitosan was protected from degradation in hemolymph, fat body, and midgut extracts collected from the honeybee. These results possibly suggest that nanoparticles-dsRNA complexes might be horizontally transferred from treated honeybee to varroa mite, in which case the honeybees could serve as RNAi vectors. We confirmed, moreover, dsRNA fed nontarget insects, honeybee, were unaffected, and no toxicity was observed for honeybee. Overall, these data suggest that dsRNA-conjugated with chitosan help escape effectively from degradation by honeybee tissue fluids and could improve RNAi efficiency in varroa mite.

Honeybees are pollinating agent of economic importance, and a model organism for microbiome analysis. The microbiota plays a great role in honeybee health and development as such needs to be fully elucidated among Apis mellifera in Korea. using 16S rRNA gene illumina sequencing, the gut microbiota of Apis mellifera at four developmental stages under natural condition shows dysbiosis of essential microbiota, especially between the 5-days larvae and workers.

The adult of honey bee, Apis mellifera, performs an age-dependent division of labor with nurse bees and foragers. Foragers fly outside the hive to collect pollen and nectar, while nurses feed and care for the larvae and queen inside the hive. Foragers are considered to be frequently exposed to agrochemicals, although nurses, stayed inside the hive, are potentially exposed to pesticides through application of miticides and pesticidecontaminated food provided by forager. Therefore, physiological effects of pesticides to nurses should be elucidated to understand the adverse effects of the chemicals on entire honey bee colony. In this study, we investigated the expression changes of the genes associated with labor division (task genes) and the nursing behavior of nurse bees fed four pesticides: acetamiprid (ACE), carbaryl (CB), imidacloprid (IMI), and fenitrothion (FEN). When nurses were exposed to ACE, IMI, and FEN, expression levels of task genes were up- and down-regulated, and their nursing behaviors were also suppressed and enhanced, respectively. CB did not alter the gene expression levels, however increased nursing behavior. These suggest the potential of pesticide that breaks the balance of labor distribution in honey bee colony.

양봉꿀벌은 한 마리 여왕벌을 중심으로 일벌 및 수벌들이 군집을 이루고 있는 사회성 곤충이다. 꿀벌은 여왕벌 이 깨어나면 처녀비행 (반경 2.4~7.4km )을 하여 공중에서 여러 마리의 수벌들과 교미를 한 후, 자신의 봉군 내부로 돌아와 평생을 살아가는 생태적 특성을 가지고 있다. 이와 같은 이유로 계통 증식 또는 품종 육종에서 외부의 오염원을 차단하기 위해서는 여왕벌과 수벌이 격리된 지역에서 교미가 이루어져야 한다. 본 연구는 여왕벌과 수벌이 격리될 수 있는 국내 도서지역을 중심으로 격리교미 연구를 2020년부터 2023년 봄부터 가을까지 수행하 였으며, 육종을 위한 격리교미의 효율성을 분석하고자 하였다. 도서지역은 전남 - 낙월도, 전북 - 위도, 왕등도, 식도에서 수행되었으며, 섬 크기, 경관 환경 요인, 교미 시기 등에 의해 격리교미의 성공률이 어떻게 변하는지를 확인하였다.

Honey bees are crucial pollinators for agricultural and natural ecosystems, but are experiencing heavy mortality in Korea due to a complex suite of factors. Extreme winter losses of honey bee colonies are a major threat to beekeeping but the combinations of factors underlying colony loss remain debatable. Finding solutions involves knowing the factors associated with high loss rates. To investigate whether loss rates are related to Varroa control and climate condition, we surveyed beekeepers in korea after wintering (2021–2022 to 2022–2023). The results show an average colony loss rate of 46%(2022) and 17%(2023), but over 40% colony loss before wintering at 2022. Beekeepers attempt to manage their honey bee colonies in ways that optimize colony health. Disentangling the impact of management from other variables affecting colony health is complicated by the diversity of practices used and difficulties handling typically complex and incomplete observational datasets. We propose a method to 1) Varroa mite population Control by several methods , and 2) Many nursing bee put in hive before wintering.

Pesticides are indispensable in contemporary agriculture but are mainly attributed to honey bee population decline. In order to understand the approximate physiological response to pesticides, honey bees were exposed to seven pesticides (Acetamiprid, Imidacloprid, Flupyradifurone, Carbaryl, Fenitrothion, Amitraz, and Bifenthrin), and expression changes of the genes categorized into four physiological functions (insecticide targets, immune-, detoxification-, and reactive oxygen species response-related gene) were analyzed in the head and abdomen of honey bee exposed to pesticides using quantitative PCR. Based on the heat map analysis, immune-related genes seem to be more up-regulated by pesticide exposure in head than abdomen. Among detoxification genes, only cytochrome P450 families were up-regulated in head. Interestingly, regardless of the insecticide target, expressions of Nicotinic acetylcholine receptor beta 1 and Acetylcholinesterase 1 were notably induced by pesticide exposure in head. Heat map analysis expressing the transcription profiles of various genes in the head and abdomen of the honey bee exposed to various pesticides can be used to diagnose pesticide damage in honey bees in the future.

국내 생산 감로꿀의 기능성 식품 소재로 활용하기 위하여 DPPH (1,1-diphenyl-2-picryl hydrazyl)와 ABTS [2,2-azobis (3-ethylbenzothiazoline- 6-sulfonate)] 라디칼 소거능, FRAP (Ferric reducing antioxidant power) 활성, 총 폴리페놀 함량 분석을 통하여 항산화 활 성을 평가하였다. 국내 생산 감로꿀은 DPPH와 ABTS 라디칼 소거 활성을 보였으며 최고농도 10 mg/mL에서 DPPH에 비하여 ABTS 라디칼 소거능이 3배 이상 높게 측정되었다. FRAP 분석에서는 ferric ion (Fe3+)를 126 μM의 ferrous (Fe2+)로 환원시켰다. 또한, 국내 생산 감로꿀에 함유된 폴리페놀성 화합물의 총량은 73.41 mg GAE/kg로 확인되었다. 이상의 연구결과에 비추어 볼 때, 국내 생산 감로꿀의 우수한 라디칼 소 거능과 환원력을 가지며 천연 항산화제로 알려진 페놀성 화합물을 존재로 인하여 항산화 활성을 가지는 것으로 확인되었다. 본 연구결과는 국내 생산 감로꿀의 기능성 식품 소재로 활용할 수 있는 기초자료로 제공하는 바이다.