RECENT HONEYBEE SCIENTIFIC PUBLICATIONS By the SNGTV* Honeybee Commission & other contributors Number 5 – February, 2020

Number – main topic that can motivate you to read the article
(First author et al ; Year ; Scientific Journal ; Impact Factor)
1- Miticides, especially formic acid, have adverse effects on memory in honey
bees (Gashout et al 2020 ; Journal of Insect Physiology ; IF 2.86)
2- Boric acid interesting to fight against Aethina tumida?
(Stuhl 2020 ; Apidologie ; IF 2.25)
3- A new genotype identified of the agent responsible for American foulbrood
(Beims et al 2020 ; International Journal of Medical Microbiology ; IF 3.36)
4- Varroa can overcome tolerance acquired by honey bees
(Eliash & Mikheyev 2020 ; Current Opinion in Insect Science ; IF 3.78)
5- A tool to measure the level of parasitic infestation without opening the hives
(Bjerge et al 2020 ; Computers and Electronics in Agriculture ; IF 3.17)
6- Honey bees, sentinels of antimicrobial resistance
(Cenci-Goga et al 2020 ; Environmental Science and Pollution Research ; IF 2.91)
7- More or less large eggs depending on several conditions
(Amiri et al 2020 ; Journal of Insect Physiology ; IF 2.54)
8- A discovery that makes the cover of the journal Science
(Leonard et al 2020 ; Science ; IF 41.06)
9- A controversy over scientific publications announcing insects decline
(Saunders et al 2020 ; BioScience ; IF 6.59)
10- Varroa sensitivity and resistance to amitraz, study in the United States
(Rinkevich 2020 ; Plos One ; IF 2.78)
11- APIMONDIA Statement on honey Fraud
International Press Review by SNGTV Honeybee commission 2
1- Miticides, especially formic acid, have adverse effects on memory in honey
Gashout, H.A., Guzman-Novoa, E., Goodwin, P.H., Correa-Benítez, A., 2020. Impact of sublethal exposure to synthetic and natural
acaricides on honey bee (Apis mellifera) memory and expression of genes related to memory. Journal of Insect Physiology
Abstract: Acaricides are used by beekeepers in honey bee (Apis mellifera L.) colonies to control
parasitic mites, but may also have adverse effects to honey bees. In this study, five commonly
used acaricides were tested for their sublethal effects on memory and expression of neuralrelated genes in honey bees. Memory measured with the proboscis extension reflex (PER) assay
was significantly reduced by topical treatment of bees with a single LD05 dose of formic acid at 2
and 24 h post treatment (hpt). However, tau-fluvalinate, amitraz, coumaphos, and formic acid,
but not thymol, resulted in memory loss at 48 hpt. The LD05 doses of the acararicides did not
affect expression of neuroligin-1, related to memory, or expression of major royal jelly protein-1,
related to both memory and development, although expression of both genes was affected at
LD50 doses. The LD05 doses of thymol, formic acid, amitraz and coumaphos increased defensin-1
expression, which is related to both memory and immunity. The effect of thymol, however, may
have been due to its impact on the immune response rather than memory. This study
demonstrates that acaricides vary in their effects on bee’s memory, and that the widely used
acaricide, formic acid, is particularly damaging.
Download not free
2- Boric acid interesting to fight against Aethina tumida?
Stuhl, C.J., 2020. The development of an attract-and-kill bait for controlling the small hive beetle (Coleoptera: Nitidulidae).
Apidologie. Abstract: This research investigates the development of an attract-and-kill bait for in-hive control
of the small hive beetle, Aethina tumida . The control method employs attracting the beetles to
an in-hive trap with a feeding attractant/stimulant where a toxicant is delivered by consuming an
edible bait. Investigations into mild insecticides led to the use of boric acid. At low doses, boric
acid is non-toxic to humans but lethal to insects. This research was designed to identify key
compounds that would attract small hive beetles, develop an edible bait using those compounds
and if the diet would be consumed by the beetle, determine the lethal dose with the lowest
amount of toxicant, and the effects the toxicant would have on the honey bee. Attractive
compounds were identified from honey bee pollen patties inoculated Kodamaea ohmeri yeast
and resulted in the identification of three key components: ethyl propionate, isobutyl
propionate, and ethyl butyrate. A diet comprised of corn gluten meal, barley flour, soy flour,
Brewer’s yeast, and glycerin containing the attractant/feeding stimulant was highly attractive and
readily consumed. In laboratory trials, the treatments containing the attract-and-kill with 2%
boric acid reduced the beetle population to zero within a few days. There was no significant
difference between the sex of the beetle for survival on any of the treatments. Honey bee
survival was reduced by ingesting the boric acid. The development of an inexpensive small hive
beetle trapping system is essential for in-hive control of this devastating pest. This system has
the potential to provide beekeepers a tool for control of this pest species that affects honey bee
health and survival worldwide.
Download not free
International Press Review by SNGTV Honeybee commission 3
3. A new genotype identified of the agent responsible for American foulbrood
Beims, H et al. 2020. Discovery of Paenibacillus larvae ERIC V: Phenotypic and genomic comparison to genotypes ERIC I-IV reveal different
inventories of virulence factors which correlate with epidemiological prevalences of American Foulbrood. Intern J of Med Microbiol 151394.
Abstract: Paenibacillus larvae is the etiological agent of American Foulbrood (AFB), a highly
contagious brood disease of honey bees (Apis mellifera). AFB requires mandatory reporting to
the veterinary authority in many countries and until now four genotypes, P. larvae ERIC I-IV, have
been identified. We isolated a new genotype, ERIC V, from a Spanish honey sample. After a
detailed phenotypic comparison with the reference strains of the ERIC I-IV genotypes, including
spore morphology, non-ribosomal peptide (NRP) profiling, and in vivo infections of A. mellifera
larvae, we established a genomic DNA Macrorestriction Fragment Pattern Analysis (MRFPA)
scheme for future epidemiologic discrimination. Whole genome comparison of the reference
strains and the new ERIC V genotype (DSM 106052) revealed that the respective virulence gene
inventories of the five genotypes corresponded with the time needed to kill 100 % of the
infected bee larvae (LT100) in in vivo infection assays. The rarely isolated P. larvae genotypes
ERIC II I-V with a fast-killing phenotype (LT100 3 days) harbor genes with high homology to
virulence factors of other insect pathogens. These virulence genes are absent in the
epidemiologically prevalent genotypes ERIC I (LT100 12 days) and ERIC II (LT100 7 days), which
exhibit slower killing phenotypes. Since killing-retardation is known to reduce the success of
hygienic cleaning by nurse bees, the identified absence of virulence factors might explain the
epidemiological prevalences of ERIC genotypes. The discovery of the P. larvae ERIC V isolate
suggests that more unknown ERIC genotypes exist in bee colonies. Since inactivation or loss of a
few genes can transform a fast-killing phenotype into a more dangerous slow-killing phenotype,
these rarely isolated genotypes may represent a hidden reservoir for future AFB outbreaks.
4. Varroa can overcome tolerance acquired by honey bees
Eliash, N., Mikheyev, A., 2020. Varroa mite evolution: A neglected aspect of worldwide bee collapses? Current Opinion in Insect Science
Abstract: While ectoparasitic Varroa mites cause minimal damage to their co-evolved ancestral
host, the eastern honey bee (Apis cerana), they devastate their novel host, the western honey
bee (Apis mellifera). Over several decades, the host switch caused worldwide population
collapses, threatening global food security. Varroa management strategies have focused on
breeding bees for tolerance. But, can Varroa overcome these counter-adaptations in a classic
coevolutionary arms race? Despite increasing evidence for Varroa genetic diversity and
evolvability, this eventuality has largely been neglected. We therefore suggest a more holistic
paradigm for studying this host-parasite interaction, one in which ‘Varroa-tolerant’ bee traits
should be viewed as a shared phenotype resulting from Varroa and honey bee interaction.
Non téléchargeable gratuitement
International Press Review by SNGTV Honeybee commission 4
5. A tool to measure the level of parasitic infestation without opening the hives
Bjerge, K., Frigaard, C.E., Mikkelsen, P.H., Nielsen, T.H., Misbih, M., Kryger, P., 2019. A computer vision system to monitor the
infestation level of Varroa destructor in a honeybee colony. Computers and Electronics in Agriculture 164, 104898.
Abstract: This paper presents a portable computer vision system, that is able to monitor the
infestation level of the Varroa destructor mite in a beehive by recording a video sequence of live
honeybees Apis mellifera for 5–20 min. A video monitoring unit with multispectral illumination
and camera was designed to be placed in front of the beehive, where bees from a selected frame
were shaken off. Subsequently, a computer vision algorithm (denoted as the Infestation Level
Estimator) based on deep learning analysis of the video stream counted the number of
honeybees and found the position of identified varroa mites. In this paper, the design and the
algorithm that were used to determine the number of bees and mites are presented. Based on a
video sequence with 1775 bees and 98 visual mites, the algorithm measured the infestation level
to 5.80% compared to a ground truth of 5.52%. The algorithm had a high F1-score accuracy for
counting bees (0.97), while the F1-score for detecting varroa mites was lower (0.91). The latter
was due to mispredictions, which can be resolved by improving both the trained varroa classifier
and the mechanical setup. Overall, the proposed computer vision system and algorithm showed
a promising results in nondestructive and automatic monitoring of infestation levels in honeybee
colonies and should be considered as an alternative to traditional methods, which require the
killing of bees.
Download not free
6. Honey bees, sentinels of antimicrobial resistance
Cenci-Goga, B.T., et al 2020. Cross-sectional study to identify risk factors associated with the occurrence of antimicrobial
resistance genes in honey bees (Apis mellifera) in Umbria, Central Italy. Environ Sci Pollut Res. Abstract: The use antimicrobials for therapeutic and metaphylactic purpose in humans and
agriculture exerts selective pressure on animal and environmental microbiota resulting in the
survival and spread of antimicrobial resistance genes among bacteria and subsequent
development of resistance in bacteria. Previous studies have shown that honey bees’ microbiota
(Apis mellifera) can accumulate antimicrobial resistance genes in their microbiome and act as
collectors and disseminators of resistance genes. The aim of this study was to investigate to what
extent honey bees act as reservoir of select antimicrobial resistance genes. This study was
conducted on 35 groups of bees. Bees were collected from 35 sites in Umbria, Italy. PCR was
used to screen pooled ground bees’ specimens for genes that code for resistance against
antimicrobials that are commonly used in humans and in veterinary medicine including
aminoglycosides (aph), beta-lactams (blaZ), tetracycline (tetM) and sulphonamides (sul1 and
sul2). Twenty four samples out of 35 (68.57%) were positive for at least one antimicrobial
resistance gene. Two samples were positive for the aph, 5.71%; eight for blaZ, 22.86%; three for
tetM, 8.57%; ten for sul1, 28.57% and eighteen for sul2, 51.43%. Positivity to more than one
antimicrobial resistance gene was observed in nine samples, 25.71%. The multivariate analysis
identified “presence of farms nearby” as the factor most closely related to PCR positivity. Honey
bees (Apis mellifera) from Umbria, Italy, carry antimicrobial resistance genes and can be used as
indicators of the presence of resistance genes in the environment.
Download not free
International Press Review by SNGTV Honeybee commission 5
7. More or less large eggs depending on several conditions
Amiri, E., Le, K., Melendez, C.V., Strand, M.K., Tarpy, D.R., Rueppell, O., 2020. Egg-size plasticity in Apis mellifera : honey bee
queens alter egg size in response to both genetic and environmental factors. Journal of Evolutionary Biology jeb.13589.
Abstract: Social evolution has led to distinct life-history patterns in social insects, but many
colony level and individual traits, such as egg size, are not sufficiently understood. Thus, a series
of experiments was performed to study the effects of genotypes, colony size, and colony
nutrition on variation in egg size produced by honey bee (Apis mellifera) queens. Queens from
different genetic stocks produced significantly different egg sizes under similar environmental
conditions, indicating standing genetic variation for egg size that allows for adaptive evolutionary
change. Further investigations revealed that eggs produced by queens in large colonies were
consistently smaller than eggs produced in small colonies, and queens dynamically adjusted egg
size in relation to colony size. Similarly, queens increased egg size in response to food
deprivation. These results could not be solely explained by different numbers of eggs produced
in the different circumstances but instead seem to reflect an active adjustment of resource
allocation by the queen in response to colony conditions. As a result, larger eggs experienced
higher subsequent survival than smaller eggs, suggesting that honey bee queens might increase
egg size under unfavorable conditions to enhance brood survival, and to minimize costly brood
care of eggs that fail to successfully develop, and thus conserve energy at the colony level. The
extensive plasticity and genetic variation of egg size in honey bees has important implications for
understanding life history evolution in a social context and implies this neglected life history
stage in honey bees may have trans-generational effects.
Download not free
8. A discovery that makes the cover of the journal Science
Leonard, S.P., Powell, J.E., Perutka, J., Geng, P., Heckmann, L.C., Horak, R.D., Davies, B.W., Ellington, A.D., Barrick, J.E., Moran,
N.A., 2020. Engineered symbionts activate honey bee immunity and limit pathogens. Science 367, 573–576.
Abstract: Honey bees are essential pollinators threatened by colony losses linked to the spread
of parasites and pathogens. Here, we report a new approach for manipulating bee gene
expression and protecting bee health. We engineered a symbiotic bee gut bacterium,
Snodgrassella alvi, to induce eukaryotic RNA interference (RNAi) immune responses. We show
that engineered S. alvi can stably recolonize bees and produce double-stranded RNA to activate
RNAi and repress host gene expression, thereby altering bee physiology, behavior, and growth.
We used this approach to improve bee survival after a viral challenge, and we show that
engineered S. alvi can kill parasitic Varroa mites by triggering the mite RNAi response. This
symbiont-mediated RNAi approach is a tool for studying bee functional genomics and potentially
for safeguarding bee health.
Download not free
International Press Review by SNGTV Honeybee commission 6
9. A controversy over scientific publications announcing insects decline
Saunders, M.E., Janes, J.K., O’Hanlon, J.C., 2020. Moving On from the Insect Apocalypse Narrative: Engaging with Evidence-Based
Insect Conservation. BioScience, Volume 70, Issue 1, January 2020, Pages 80–89.
Abstract: Recent studies showing temporal changes in local and regional insect populations
received exaggerated global media coverage. Confusing and inaccurate science communication
on this important issue could have counterproductive effects on public support for insect
conservation. The insect apocalypse narrative is fuelled by a limited number of studies that are
restricted geographically (predominantly the United Kingdom, Europe, the United States) and
taxonomically (predominantly some bees, macrolepidoptera, and ground beetles). Biases in
sampling and analytical methods (e.g., categorical versus continuous time series, different
diversity metrics) limit the relevance of these studies as evidence of generalized global insect
decline. Rather, the value of this research lies in highlighting important areas for priority
investment. We summarize research, communication, and policy priorities for evidence-based
insect conservation, including key areas of knowledge to increase understanding of insect
population dynamics. Importantly, we advocate for a balanced perspective in science
communication to better serve both public and scientific interests.
Download not free
10. Varroa sensitivity and resistance to amitraz, study in the United States
Rinkevich, F.D., 2020. Detection of amitraz resistance and reduced treatment efficacy in the Varroa Mite, Varroa destructor,
within commercial beekeeping operations. PLoS ONE 15, e0227264.
Abstract: The parasitic mite Varroa destructor and the associated viruses it transmits are
responsible for most instances of honey bee colony losses in the United States. As such,
beekeepers utilize miticides to control Varroa populations. Widespread resistance has developed
to the miticides fluvalinate and coumaphos. However, Varroa has largely maintained
susceptibility to amitraz despite a long and extensive use history. Anecdotal reports of reduced
amitraz effectiveness have been a widely discussed contemporary issue among commercial
beekeepers. Amitraz resistance was measured by in vitro bioassays with technical amitraz as well
as Apivar® efficacy tests. Amitraz resistance was evaluated in commercial beekeeping operations
in Louisiana, New York, and South Dakota with a long history of amitraz use. This research shows
that amitraz remains an effective Varroa control product in many operations. However, apiaries
across operations displayed a wide range of amitraz resistance from no resistance to high
resistance that resulted in Varroa control failure. The resistance ratios from in vitro amitraz
bioassays were correlated with reduced Apivar® efficacy, demonstrating bona fide cases of
Varroa control failures due to amitraz resistance. Therefore, amitraz resistance monitoring
protocols need to be developed. A resistance monitoring network should be established to
ensure the sustainability of miticide use for Varroa control.
International Press Review by SNGTV Honeybee commission 7
11. APIMONDIA Statement on honey Fraud
APIMONDIA Statement on Honey Fraud is the official position of APIMONDIA regarding honey
purity, authenticity, fair modes of production, and the best available recommended methods to
detect and prevent honey fraud.
This Statement aims to be a trusted source for authorities, traders, supermarkets, retailers,
manufacturers, consumers, and other stakeholders of the honey trade chain to ensure they stay
updated with the current concepts and new testing developments regarding honey purity and
authenticity. It is also a guide to promote best practices for the prevention of honey fraud and all
of its insidious negative side effects on bees, beekeepers, crop pollination, and food security.