Breeding the Mite-Resistant Honeybee by Nutritional Crossbreed Technology

Mite （Varroa destructor） is one of the most serious parasite threats to the honey bee （Apis mellifera） reared in China. The beekeepers mainly use the drug to control and kill the mite in the past years, but the honey products may be contaminated and the mite is becoming drug-resistant. The main idea of this paper is to research the possibility of mite-resistant honeybee rearing by nutritional crossbreed. The larvae （Apis mellifera ligustica） are bred with the royal jelly of Apis carana carana, and then the morphological index of the worker generation, genotypic frequency and gene frequency of the MDH Ⅱ, genetic resemblance, and mite resistance are measured. The results show that： compared to the parent workers, the proboscis length, anterior wing area, the total length of the third and fourth dorsal plate of the abdomen, the length of the fourth dorsal plate of the tuberculum, the area of the sixth abdominal segment, and the area of wax mirrors are significantly different, but the differences in the brachium index, dactylus index, and wing claw are not significant. Moreover, there are some mutations in the genotypic frequency and gene frequency of the MDH Ⅱ. The mite resistance of the nutritional crossbreed worker is significantly higher. The morphological, physical, and biochemical characters, genetic resemblance, and the mite-resistant ability of the worker generation can be changed by nutritional crossbreeding. Nutritional crossbreeding can be a new way to breed the honeybee.

RFID monitoring indicates honeybees work harder before a rainy day

Storms are usually accompanied by a drop in tempera- ture, and an increase in wind and barometric pressure and rainfall, which have negative impacts on most activ- ities, survival and reproduction in insects （Gillot, 2005）. The majority of studies have mainly focused on how the flight activity of various flying insects such as honey- bees, bumble bees, horse flies and leafminers were directly influenced by intraday weather changes （Burnett ＆ Hays, 1974; Lundberg, 1980; Casas, 1989; Vicens ＆ Bosch, 2000）.

A comparison of honeybee (Apis mellifera) queen, worker and drone larvae by RNA-Seq

Honeybees (Apis mellifera) have haplodiploid sex determination: males develop from unfertilized eggs and females develop from fertilized ones. The differences in larval food also determine the development of females. Here we compared the total somatic gene expression profiles of 2-day and 4-day-old drone, queen and worker larvae by RNASeq. The results from a co-expression network analysis on all expressed genes showed that 2-day-old drone and worker larvae were closer in gene expression profiles than 2-day-old queen larvae. This indicated that for young larvae (2-day-old) environmental factors such as larval diet have a greater effect on gene expression profiles than ploidy or sex determination. Drones had the most distinct gene expression profiles at the 4-day larval stage, suggesting that haploidy, or sex dramatically affects the gene expression of honeybee larvae. Drone larvae showed fewer differences in gene expression profiles at the 2-day and 4-day time points than the worker and queen larval comparisons (598 against 1190 and 1181), suggesting a different pattern of gene expression regulation during the larval development of haploid males compared to diploid females. This study indicates that early in development the queen caste has the most distinct gene expression profile, perhaps reflecting the very rapid growth and morphological specialization of this caste compared to workers and drones. Later in development the haploid male drones have the most distinct gene expression profile, perhaps reflecting the influence of ploidy or sex determination on gene expression.

Varroa destructor mite infestations in capped brood cells of honeybee workers affect emergence development and adult foraging ability

Given recent higher declines in managed Apis mellifera honeybees,which are the most commonly managed bee species around the world(Garibaldi et al.2013),numerous health threats involved in the losses have been received great attention.To date,Varroa destructor mite infestation has become the biggest challenge in commercial beekeeping,which is considered as a thorn stuck in the throat of beekeepers.The Varroa mite threatens bee health by absorbing the fat body and hemolymph of immature and mature bees(Ramsey et al.2019).Varroa mite infestation during the development of worker bees was found to reduce birth weight,influence water content and protein level in hemolymph of newly emerged worker bees,decrease flight performance of drones,change gene expression patterns related to immune system of honeybees,and result in honeybee colony losses(Duay et al.2002;Bowen-Walker and Gunn 2010;Zhang et al.2010;Annoscia et al.2012;Dooremalen et al.2013;Locke 2016).The Varroa mite,as an ectoparasite of the honeybee,prefers living in the sealed brood cells(Bogdanov 2006).Thus,bees are more likely to become hosts of mites in the pupal stage.In this study,we systematically investigated the current impacts of V.destructor infestations on the development from capped larvae to emerged bees.

The difference in composition and nutritional potency of honey extracted by centrifugation and pressed processes

In traditional beekeeping,the two most important methods for extracting honey are centrifugation and honeycomb-pressing.In this study,the physicochemical composition of honey samples extracted using two distinct procedures was compared,as well as the impact of antioxidant capacity and nutritional potency on the lifespan and learning memory of worker bees.Honey samples were collected from ten colonies of Apis cerana:five samples via centrifugation and five via honeycomb-pressing.Our results showed that honey extraction methods influence the nutri-tional composition and potency of honey.Most parameters were superior in pressed honey,and the amylase activity in centrifuged honey was higher.The effects of antioxidant capacity and nutritional potency on worker bees'lifespans and learning memory were also superior in pressed honey.Pressed honey had higher nutritional composition and potency.However,whether pressed honey,which is rich in pollen,spoils more easilyrequiresfurtherinvestigation.

The integrative analysis of microRNA and mRNA expression in Apis mellifera following maze-based visual pattern learning

The honeybee （Apis mellifera） is a social insect with strong sensory capacity and diverse behavioral repertoire and is recognized as a good model organism for studying the neurobiological basis of learning and memory. In this study, we analyzed the changes in microRNA （miRNA） and messenger RNA （mRNA） following maze-based visual learning using next-generation small RNA sequencing and Solexa/lllumina Digital Gene Expression tag profiling （DGE）. For small RNA sequencing, we obtained 13 367 770 and 13 132 655 clean tags from the maze and control groups, respectively. A total of 40 differentially expressed known miRNAs were detected between these two samples, and all of them were up-regulated in the maze group compared to the control group. For DGE, 5 681 320 and 5 939 855 clean tags were detected from the maze and control groups, respectively. There were a total of 388 differentially expressed genes between these two samples, with 45 genes up-regulated and 343 genes down-regulated in the maze group, compared to the control group. Additionally, the expression levels of 10 differentially expressed genes were confirmed by quantitative reverse transcription polymerase chain reaction （qRT-PCR） and the expression trends of eight of them were consistent with the DGE result, although the degree of change was lower in amplitude. The integrative analysis of miRNA and mRNA expression showed that, among the 40 differentially expressed known miRNAs and 388 differentially expressed genes, 60 pairs of miRNA/mRNA were identified as co-expressed in our present study. These results suggest that both miRNA and mRNA may play a pivotal role in the process of learning and memory in honeybees. Our sequencing data provide comprehensive miRNA and gene expression information for maze-based visual learning, which will facilitate understanding of the molecular mechanisms of honeybee learning and memory.

csd alleles in the red dwarf honey bee （Apis florea, Hymenoptera： Apidae） show exceptionally high nucleotide diversity

The single locus complementary sex determination （sl-csd） gene is the primary gene determining the gender of honey bees （Apis spp.）. While the csd gene has been well studied in the Western honey bee （Apis mellifera）, and comparable data exist in both the Eastern honey bee （Apis cerana） and the giant honey bee （Apis dorsata）, no studies have been conducted in the red dwarf honey bee, Apisflorea. In this study we cloned the genomic region 3 of the A. florea csd gene from 60 workers, and identified 12 csd alleles. Analysis showed that similar to A. mellifera, region 3 of the csd gene contains a RS domain at the N terminal, a proline-rich domain at the C terminal, and a hypervariable region in the middle. However, the A. florea csd gene possessed a much higher level of nucleotide diversity, compared to A. mellifera, A. cerana and Apis dorsata. We also show that similar to the other three Apis species, in A. florea, nonsynonymous mutations in the csd gene are selectively favored in young alleles.