Prevalence and distribution of Varroa destructor and Nosema spp. in symptomatic honey bee colonies across the USA from 2015 to 2022.

USDA-ARS Bee Research Laboratory received symptomatic honey bee (Apis mellifera L.) samples across the United States for disease diagnosis. Here, we present a retrospective study and cartography of ectoparasite Varroa destructor and intracellular microsporidia parasite Nosema spp. These two major parasites were identified in the diseased honey bee samples between 2015 and 2022. Varroa infestation level (VIL) was examined by a wash technique (Mites/100 bees) and calculated as a percentage, while Nosema infection was quantified by microscopical spore count (Million Spores/Bee). Data were analyzed by month, year, state, and by nine geographical climate regions described in the U.S. Of adult bee samples (n = 4039) that were analyzed for Varroa mite infestation, the overall VIL in the U.S. ranged between 0.4 and 30.85%, with an overall national VIL and Varroa prevalence of 8.21% and 85.14%, respectively. Overall monthly data showed VIL constantly exceeded the critical level of 4% except from June to September and reached a maximum of 15% in January and December. Nationwide, VIL significantly (p < 0.001) increased from 2015 to 2018 (1.1-4.7%), plateaued from 2018 to 2021 (4.7-4.5%), followed by a significant decrease in 2022 (3.6%). Significant VIL differences (p < 0.001) were recorded among climate regions, with the highest mite infestation levels in the Upper Midwest region (13.9%) and the lowest in the West region (5.1%). Of adult bee samples (n = 2,994) that were analyzed for Nosema infection, Nosema spore count ranged between (1-16.8) million spores per bee among states, with a national average of 6.8 and a prevalence of 99.7%. The lowest and highest Nosema loads were respectively recorded in the South region (3.1) and Upper Midwest (10.5), a significant difference (p < 0.001). No statistical differences were recorded among the six other climate regions. Overall, VIL and Nosema infection correlated significantly (p < 0.001) with a regression coefficient of (R2 = 0.6). Our data, which originated from ailing bee colonies, showed significantly higher rates of maladies compared to data from healthy colonies obtained by the USDA-APHIS National Honey Bee Survey, demonstrating the role of bee diseases caused by Varroa mite and Nosema in honey bee population declines.

Bacterial diversity using metagenomics of 16s rDNA in water kefir, an innovative source of probiotics for bee nutrition.

Water kefir is a sparkling, slightly acidic fermented beverage made from sugar, water, and water kefir grains, which are a mixture of yeast and bacteria. These grains produce a variety of fermentation compounds such as lactic acid, acetaldehyde, acetoin, ethanol and carbon dioxide. In this study, a high-throughput sequencing technique was used to characterize the bacterial composition of the original water kefir from which potential probiotics were obtained. We studied the bacterial diversity of both water kefir grains and beverages. DNA was extracted from three replicate samples of both grains and beverages using the Powerlyzer Microbial Kit. The hypervariable V1-V2 region of the bacterial 16S ribosomal RNA gene was amplified to prepare six DNA libraries. Between 1.4M and 2.4M base-pairs were sequenced for the library. In total, 28721971 raw reads were obtained from all the samples. Estimated species richness was higher in kefir beverage samples compared to grain samples. Moreover, a higher level of microbial alpha diversity was observed in the beverage samples. Particularly, the predominant bacteria in beverages were Anaerocolumna and Ralstonia, while in grains Liquorilactobacillus dominated, with lower levels of Leuconostoc and Oenococcus. Although the bacterial diversity in kefir grains was low because only three genera were the most represented, all of them are LAB bacteria with the potential to serve as probiotics in the artificial feeding of bees.

Synthesis of Composites for the Removal of F- Anions.

This work presents the synthesis of amine and ferrihydrite functionalized graphene oxide for the removal of fluoride from water. The synthesis of the graphene oxide and the modified with amine groups is developed by following the modified Hummer's method. Fourier transform infrared spectrometry, X-ray, Raman spectroscopy, thermogravimetric analysis, surface charge distribution, specific surface area and porosity, adsorption isotherms, and the van't Hoff equation are used for the characterization of the synthesized materials. Results show that the addition of amines with ferrihydrite generates wrinkles on the surface layers, suggesting a successful incorporation of nitrogen onto the graphene oxide; and as a consequence, the adsorption capacity per unit area of the materials is increased.

Microbiological and Chemical characterization of water kefir: An innovative source of potential probiotics for bee nutrition / Caracterización microbiológica y química del kéfir de agua: una fuente innovadora de potenciales probióticos para la nutrición de las abejas

Abstract We evaluated the microbial composition of water kefir grains and beverage overthe course of one year to determine whether the number and type of microorganisms changedover the time. Bacteria and yeast colonies with different morphologies were isolated fromwater kefir and their antimicrobial activity was evaluated against Paenibacillus larvae andAscosphaera apis. A chemical characterization of kefir was also carried out. Our results con-firmed that bacteria and yeasts were more numerous in kefir grains compared with those in thebeverage. The counts of microorganisms declined, although an important microbial community was still present in kefir after the long storage period. Eleven strains which inhibited bee pathogens were isolated from kefir. Genotypic results demonstrated that these isolates included Lentilactobacillus hilgardii, Lentilactobacillus buchneri and Saccharomyces cerevisiae. Thus, water kefir may be an innovative source of potential probiotic strains for bee nutrition in order to control honeybee diseases.

Resumen Evaluamos la composición microbiana del kéfir de agua durante un ano para determinar si la cantidad y el tipo de microorganismos cambiaban con el tiempo. Se aislaron colonias de bacterias y de levaduras con diferentes morfologías, y su actividad antimicrobiana se evaluó frente a Paenibacillus larvaey Ascosphaeraapis. También se realizó una caracterización química del kéfir. Nuestros resultados confirmaron que las bacterias y las levaduras eran más numerosas en los gránulos de kéfir en comparación con la parte líquida. Los recuentos de microorganismos disminuyeron, aunque una cantidad igualmente importante se encontró en el kéfir después de un año. Se aislaron del kéfir once cepas que inhibieron los mencionados patógenos de abejas. Los resultados genotípicos demostraron que estos aislamientos eran Lentilactobacillus hilgardii, Lentilactobacillus buchneri y Saccharomyces cerevisiae. Por lo tanto, el kéfir de agua podría ser una fuente innovadora de potenciales cepas probióticas para contribuir a la nutrición y sanidad de las abejas.

Decoupling the effects of nutrition, age, and behavioral caste on honey bee physiology, immunity, and colony health.

Nutritional stress, especially a dearth of pollen, has been linked to honey bee colony losses. Colony-level experiments are critical for understanding the mechanisms by which nutritional stress affects individual honey bee physiology and pushes honey bee colonies to collapse. In this study, we investigated the impact of pollen restriction on key markers of honey bee physiology, main elements of the immune system, and predominant honey bee viruses. To achieve this objective, we uncoupled the effects of behavior, age, and nutritional conditions using a new colony establishment technique designed to control size, demography, and genetic background. Our results showed that the expression of storage proteins, including vitellogenin (vg) and royal jelly major protein 1 (mrjp1), were significantly associated with nursing, pollen ingestion, and older age. On the other hand, genes involved in hormonal regulation including insulin-like peptides (ilp1 and ilp2) and methyl farnesoate epoxidase (mfe), exhibited higher expression levels in young foragers from colonies not experiencing pollen restriction. In contrast, pollen restriction induced higher levels of insulin-like peptides in old nurses. On the other hand, we found a strong effect of behavior on the expression of all immune genes, with higher expression levels in foragers. In contrast, the effects of nutrition and age were significant only the expression of the regulatory gene dorsal. We also found multiple interactions of the experimental variables on viral titers, including higher Deformed wing virus (DWV) titers associated with foraging and age-related decline. In addition, nutrition significantly affected DWV titers in young nurses, with higher titers induced by pollen ingestion. In contrast, higher levels of Black queen cell virus (BQCV) were associated with pollen restriction. Finally, correlation, PCA, and NMDS analyses proved that behavior had had the strongest effect on gene expression and viral titers, followed by age and nutrition. These analyses also support multiple interactions among genes and virus analyzed, including negative correlations between the expression of genes encoding storage proteins associated with pollen ingestion and nursing (vg and mrjp1) with the expression of immune genes and DWV titers. Our results provide new insights into the proximal mechanisms by which nutritional stress is associated with changes in honey bee physiology, immunity, and viral titers.

Mediating a host cell signaling pathway linked to overwinter mortality offers a promising therapeutic approach for improving bee health.

INTRODUCTION: Honey bees provides valuable pollination services for world food crops and wild flowering plants which are habitats of many animal species and remove carbon dioxide from the atmosphere, a powerful tool in the fight against climate change. Nevertheless, the honey bee population has been declining and the majority of colony losses occur during the winter. OBJECTIVES: The goal of this study was to understand the mechanisms underlying overwinter colony losses and develop novel therapeutic strategies for improving bee health. METHODS: First, pathogen prevalence in overwintering bees were screened between 2015 and 2018. Second, RNA sequencing (RNA-Seq) for transcriptional profiling of overwintering honey bees was conducted and qRT-PCR was performed to confirm the results of the differential expression of selected genes. Lastly, laboratory bioassays were conducted to measure the effects of cold challenges on bee survivorship and stress responses and to assess the effect of a novel medication for alleviating cold stress in honey bees. RESULTS: We identified that sirtuin signaling pathway is the most significantly enriched pathway among the down-regulated differentially expressed genes (DEGs) in overwintering diseased bees. Moreover, we showed that the expression of SIRT1 gene, a major sirtuin that regulates energy and immune metabolism, was significantly downregulated in bees merely exposed to cold challenges, linking cold stress with altered gene expression of SIRT1. Furthermore, we demonstrated that activation of SIRT1 gene expression by SRT1720, an activator of SIRT1 expression, could improve the physiology and extend the lifespan of cold-stressed bees. CONCLUSION: Our study suggests that increased energy consumption of overwintering bees for maintaining hive temperature reduces the allocation of energy toward immune functions, thus making the overwintering bees more susceptible to disease infections and leading to high winter colony losses. The novel information gained from this study provides a promising avenue for the development of therapeutic strategies for mitigating colony losses, both overwinter and annually.

Microbiological and chemical characterization of water kefir: An innovative source of potential probiotics for bee nutrition.

We evaluated the microbial composition of water kefir grains and beverage over the course of one year to determine whether the number and type of microorganisms changed over the time. Bacteria and yeast colonies with different morphologies were isolated from water kefir and their antimicrobial activity was evaluated against Paenibacillus larvae and Ascosphaera apis. A chemical characterization of kefir was also carried out. Our results confirmed that bacteria and yeasts were more numerous in kefir grains compared with those in the beverage. The counts of microorganisms declined, although an important microbial community was still present in kefir after the long storage period. Eleven strains which inhibited bee pathogens were isolated from kefir. Genotypic results demonstrated that these isolates included Lentilactobacillus hilgardii, Lentilactobacillus buchneri and Saccharomyces cerevisiae. Thus, water kefir may be an innovative source of potential probiotic strains for bee nutrition in order to control honeybee diseases.

Antiparasitic effects of three floral volatiles on trypanosomatid infection in honey bees.

Trypanosomatid gut parasites are common in pollinators and costly for social bees. The recently described honey bee trypanosomatid Lotmaria passim is widespread, abundant, and correlated with colony losses in some studies. The potential for amelioration of infection by antimicrobial plant compounds has been thoroughly studied for closely related trypanosomatids of humans and is an area of active research in bumble bees, but remains relatively unexplored in honey bees. We recently identified several floral volatiles that inhibited growth of L. passim in vitro. Here, we tested the dose-dependent effects of four such compounds on infection, mortality, and food consumption in parasite-inoculated honey bees. We found that diets containing the monoterpenoid carvacrol and the phenylpropanoids cinnamaldehyde and eugenol at > 10-fold the inhibitory concentrations for cell cultures reduced infection, with parasite numbers decreased by > 90 % for carvacrol and cinnamaldehyde and > 99 % for eugenol; effects of the carvacrol isomer thymol were non-significant. However, both carvacrol and eugenol also reduced bee survival, whereas parasite inoculation did not, indicating costs of phytochemical exposure that could exceed those of infection itself. To our knowledge, this is the first controlled screening of phytochemicals for effects on honey bee trypanosomatid infection, identifying potential treatments for managed bees afflicted with a newly characterized, cosmopolitan intestinal parasite.

Analysis of the economic effects on biopsychosocial homeostasis from a three-dimensional probability measurement system.

OBJECTIVE: Describes the economic effects on bio-psychosocial homeostasis from a three-dimensional analysis of the joint interaction of biological, psychological and economic-social comorbidities, in order to know the probabilities of occurrence of these conditions simultaneously. METHOD: It is a cross-sectional study and random quota sampling. 353 men and women over 20 years of age participated, and answered a 27 questions application (bio-psycho-economic-social), the data was analyzed three-dimensionally in order to know the probability of occurrence of the variables studied and their possible location in the probabilistic unit cube. RESULTS: Based on the unit cube proposal, it can be observed that in the block of people with incomes from 2200 to 6600 pesos in the group of men there is a probability of 12.9 per 1000 inhabitants of presenting debt problems, overweight and severe depression, while in the case of women, the probability is 2.08 per 1000 inhabitants. CONCLUSIONS: There is a priority axis that determines the change of the remaining variables, in this case it is the economic axis the one that determines the biological and psychological conditions.

OBJETIVO: Describir los efectos económicos en la homeostasis biopsicosocial a partir de un análisis tridimensional de la interacción conjunta de la comorbilidad biológica, psicológica y económico-social, con la finalidad de conocer las probabilidades de ocurrencia a partir de estas condiciones de forma simultánea. MÉTODO: Estudio transversal y muestreo aleatorio por cuotas. Participaron 353 hombres y mujeres mayores de 20 años que contestaron un cuestionario con 27 preguntas (biopsicosociales-económicas). Se analizaron los datos tridimensionalmente con la finalidad de conocer la probabilidad de ocurrencia de las variables estudiadas y su posible localización en el cubo unitario probabilístico. RESULTADOS: Con base en la propuesta del cubo unitario se obtiene que, en las personas con ingresos de 2200 a 6600 pesos, en los hombres existe una probabilidad de 12.9 por cada 1000 habitantes de presentar deudas, sobrepeso y depresión grave; en las mujeres, la probabilidad es de 2.08 por cada 1000 habitantes. CONCLUSIONES: Existe un eje prioritario que determina el cambio de las variables restantes, en este caso el eje económico que determina las condiciones biológicas y psicológicas.

A case report, bilateral spontaneous pneumothorax as a late complication for SARS CoV-2 infection.

The beta-coronavirus discovered in Wuhan in 2019 (COVID-19) provokes a series of affections from mild symptoms to life-threatening complications. There is evidence that associates the disease to spontaneous pneumothorax, however, the mechanism is unknown. The patient was a 45-year-old male with previous pneumonia due to COVID-19 who was attended the emergency department, where chest radiography was taken, confirming the diagnosis of right pneumothorax. However, the patient developed a new episode of pleuritic pain three days later, and a new radiograph showed left pneumothorax requiring a new chest tube. The simple tomography shows intraparenchymal bullae in the apical region of both lungs. The patient was kept under observation, and when improving, both endopleural chest drains were removed, and the patient was discharged. Spontaneous bilateral pneumothorax is a rare and potentially life-threatening complication. Identifying pulmonary bullae in patients with COVID-19 could be an early sign for these patients to develop spontaneous pneumothorax.

Localization of irritative zones in epilepsy with thermochromic silicone.

BACKGROUND: During epilepsy surgery, the gold standard to identify irritative zones (IZ) is electrocorticography (ECoG); however, new techniques are being developed to detect IZ in epilepsy surgery and in neurosurgery in general, such as infrared thermography mapping (ITM), and the use of thermosensitive/thermochromic materials. METHODS: In a cohort study of consecutive patients with focal drug-resistant epilepsy of the temporal lobe treated with surgery, we evaluated possible adverse effects to the transient placement of a thermochromic/thermosensitive silicone (TTS) on the cerebral cortex and their postoperative evolution. Furthermore, we compared the precision of TTS for detecting cortical IZ against the gold standard ECoG and with ITM, as proof of concept. RESULTS: We included 10 consecutive patients, 6 women (60%) and 4 men (40%). Age ranges from 15 to 56 years, mean 33.2 years. All were treated with unilateral temporal functional lobectomy. The mean hospital stay was 4 days. There were no immediate or late complications associated with the use of any of the modalities described. In the 10 patients, we obtained consistency in locating the IZ with ECoG, ITM, and the TTS. CONCLUSION: The TTS demonstrated biosecurity in this series. The accuracy of the TTS to locate IZ was similar to that of ECoG and ITM in this study. More extensive studies are required to determine its sensitivity and specificity.

Africanized honey bees in Colombia exhibit high prevalence but low level of infestation of Varroa mites and low prevalence of pathogenic viruses.

The global spread of the ectoparasitic mite Varroa destructor has promoted the spread and virulence of highly infectious honey bee viruses. This phenomenon is considered the leading cause for the increased number of colony losses experienced by the mite-susceptible European honey bee populations in the Northern hemisphere. Most of the honey bee populations in Central and South America are Africanized honey bees (AHBs), which are considered more resistant to Varroa compared to European honey bees. However, the relationship between Varroa levels and the spread of honey bee viruses in AHBs remains unknown. In this study, we determined Varroa prevalence and infestation levels as well as the prevalence of seven major honey bee viruses in AHBs from three regions of Colombia. We found that although Varroa exhibited high prevalence (92%), its infestation levels were low (4.5%) considering that these populations never received acaricide treatments. We also detected four viruses in the three regions analyzed, but all colonies were asymptomatic, and virus prevalence was considerably lower than those found in other countries with higher rates of mite-associated colony loss (DWV 19.88%, BQCV 17.39%, SBV 23.4%, ABPV 10.56%). Our findings indicate that AHBs possess a natural resistance to Varroa that does not prevent the spread of this parasite among their population, but restrains mite population growth and suppresses the prevalence and pathogenicity of mite-associated viruses.

[Uncertainty, dynamic systems, principles of quantum mechanics and their relationship to the health-disease process (analysis proposal).] / Incertidumbre, sistemas dinámicos, principios de mecánica cuántica y su relación con el proceso salud-enfermedad (propuesta de análisis).

The purpose of this work is to discuss the importance and possible application of some foundations of quantum mechanics in the health-disease process, considering for this, that the laws and foundations of atomic theory are the same that govern displacement in space and time in human beings. Based on the impossibility of determining the displacement of subatomic particles in a given space and time, as a consequence of not having measuring instruments for said microscales, we propose feasible that the same happens with the uncertainty generated by the times and movements of human beings in really large spaces, reason why the analysis of the temporo-spatial location of a moving subject, in a certain time and space is impossible, fact that we consider, could represent the behavior in Pandemics. The foundations of quantum mechanics that have been considered for this purpose are dynamic systems, the Schrödinger cat paradox, the Heisenberg uncertainty principle, the law of gases, times and movements, and the Maxwell-Boltzmann entropy. On the other hand, it is proposed to consider the adaptation of measurement ecis ecisión statistical procedures (decisión tree and set theory) and finally the implementation of a unitary probabilistic cube is proposed, which allows locating a subject immersed in the health process disease through three axes developed considering the definition of health stipulated by the WHO.

El presente trabajo tuvo como finalidad discutir la importancia y la posible aplicación de algunos fundamentos de la mecánica cuántica en el proceso de salud-enfermedad, considerando para esto que las leyes y fundamentos de la teoría atómica son los mismos que rigen los desplazamientos en el espacio y el tiempo en los seres humanos. Con base en la imposibilidad de determinar el desplazamiento de las partículas subatómicas en un espacio y tiempo determinado, como consecuencia de no contar con instrumentos de medición para dichas microescalas, consideramos factible que lo mismo suceda con la incertidumbre generada por los tiempos y movimientos de los seres humanos en espacios realmente grandes, por lo que el análisis de la ubicación temporo-espacial de un sujeto en movimiento, en un tiempo y en un espacio determinado, es imposible. Creemos que este hecho podría representar el comportamiento en las pandemias. Los fundamentos de la mecánica cuántica que se han considerado con dicho fin son: los sistemas dinámicos; la paradoja del gato de Schrödinger; el principio de incertidumbre de Heisenberg; la ley de gases, tiempos y movimientos; la entropía de Maxwell-Boltzmann. Por otra parte, se propone considerar la adaptación de herramientas de medición basadas en procedimientos estadísticos (árbol de decisiones y teoría de conjuntos) y, finalmente, se propone la implementación de un cubo probabilístico unitario, el cual permita ubicar a un sujeto inmerso en el proceso de salud-enfermedad mediante tres ejes desarrollados según la definición de salud estipulada por la Organización Mundial de la Salud.

Thermography mapping patterns in temporal lobe epilepsy surgery.

BACKGROUND: In several epilepsy etiologies, the macroscopic appearance of the epileptogenic tissue is identical to the normal, which makes it hard to balance between how much cytoreduction or disconnection and brain tissue preservation must be done. A strategy to tackle this situation is by evaluating brain metabolism during surgery using infrared thermography mapping (IrTM). METHODS: In 12 epilepsy surgery cases that involved the temporal lobe, we correlated the IrTM, electrocorticography, and neuropathology results. RESULTS: Irritative zones (IZ) had a lower temperature in comparison to the surrounding cortex with normal electric activity (difference in temperature (ΔT) from 1.2 to 7.1, mean 3.40°C standard deviation ± 1.61). The coldest zones correlated exactly with IZ in 9/10 cortical dysplasia (CD) cases. In case 3, the coldest area was at 1 cm away from the IZ. In 10/10 dysplasia cases (cases 1-4, 6-11), there was a radial heating pattern originating from the coldest cortical point. In 2/2 neoplasia cases, the temporal lobe cortical temperature was more homogeneous than in the CD cases, with no radial heating pattern, and there were no IZ detected. In case 8, we found the coldest IrTM recording in the hippocampus, which correlated to the maximal irritative activity recorded by strip electrodes. The ΔT is inversely proportional to epilepsy chronicity. CONCLUSION: IrTM could be useful in detecting hypothermic IZ in CD cases. As the ΔT is inversely proportional to epilepsy chronicity, this variable could affect the metabolic thermic patterns of the human brain.

Propuesta para la determinación del cambio de velocidad, velocidad instantánea y aceleración con base en el puntaje APACHE II en pacientes en estado crítico / Proposal for the determination of velocity change, instantaneous velocity and aceleration from the APACHE II score in critically ill patients / Proposta para a determinação da mudança de velocidade, velocidade instantânea e aceleração baseada no escore APACHE II em pacientes críticos

Resumen: Las herramientas de evaluación de la gravedad en el enfermo grave proporcionan información objetiva intra e interobservador relacionada con la gravedad de la enfermedad, su evolución en relación al tiempo y la estratificación de riesgo son parte fundamental en la toma de decisiones. El objetivo de este trabajo es presentar una nueva propuesta de la evaluación del APACHE II basada en un modelo matemático de cambio en el tiempo/velocidad, velocidad instantánea y aceleración.

Abstract: The illness severity scoring systems provide objetive measures for inter and intra comparisons with time, provide useful information for comparing the severity of illness are an essencial part of the improvment in clinical decisions and in stratifying patients. Appropiated application of these models helps in decision making at the right time. The aim of this paper is to submit a proposal for the evaluation of the APACHE II score based on a vectorial mathematical model of chance in time/velocity, instant velocity and aceleration.

Resumo: Os instrumentos de avaliação da gravidade do paciente grave fornecem informações objetivas intra e interobservadores relacionadas à gravidade da doença, sua evolução em relação ao tempo, estratificação de risco são fundamentais para tomada de decisão. O objetivo deste trabalho é apresentar uma nova proposta para a avaliação do APACHE II baseada em um modelo matemático de mudança de tempo/velocidade, velocidade instantânea e aceleração.

Comparative transcriptome analysis on the synthesis pathway of honey bee (Apis mellifera) mandibular gland secretions.

Secretions from mandibular glands (MGs) have important caste-specific functions that are associated with the social evolution of honey bees. To gain insights into the molecular architecture underlying these caste differences, we compared the gene expression patterns of MGs from queens, queenright workers (WQRs) and queenless workers (WQLs) using high-throughput RNA-sequencing technology. In total, we identified 46 candidate genes associated with caste-specific biosynthesis of fatty acid pheromones in the MG, including members of cytochrome P450 (CYP450) family and genes involved in fatty acid ß-oxidation and ω-oxidation. For further identification of the CYP450s genes involved in the biosynthesis of MG secretions, we analyzed by means of qPCR, the expression levels of six of the CYP450 genes most abundantly expressed in the transcriptome analysis across different castes, ages, tasks and tissues. Our analysis revealed that CYP6AS8 and CYP6AS11, the most abundantly expressed CYP450 genes in worker and queen MGs, respectively, are selectively expressed in the MGs of workers and queens compared to other tissues. These results suggest that these genes might be responsible for the critical bifurcated hydroxylation process in the biosynthesis pathway. Our study contributes to the description of the molecular basis for the biosynthesis of fatty acid-derived pheromones in the MGs.

Molecular mechanisms of phenotypic plasticity in social insects.

Polyphenism in insects, whereby a single genome expresses different phenotypes in response to environmental cues, is a fascinating biological phenomenon. Social insects are especially intriguing examples of phenotypic plasticity because division of labor results in the development of extreme morphological phenotypes, such as the queen and worker castes. Although sociality evolved independently in ants, bees, wasps and termites, similar genetic pathways regulate phenotypic plasticity in these different groups of social insects. The insulin/insulin-like growth signaling (IIS) plays a key role in this process. Recent research reveals that IIS interacts with other pathways including target of rapamycin (TOR), epidermal growth factor receptor (Egfr), juvenile hormone (JH) and vitellogenin (Vg) to regulate caste differentiation.

Overwintering Is Associated with Reduced Expression of Immune Genes and Higher Susceptibility to Virus Infection in Honey Bees.

The eusocial honey bee, Apis mellifera, has evolved remarkable abilities to survive extreme seasonal differences in temperature and availability of resources by dividing the worker caste into two groups that differ in physiology and lifespan: summer and winter bees. Most of the recent major losses of managed honey bee colonies occur during the winter, suggesting that winter bees may have compromised immune function and higher susceptibility to diseases. We tested this hypothesis by comparing the expression of eight immune genes and naturally occurring infection levels of deformed wing virus (DWV), one of the most widespread viruses in A. mellifera populations, between summer and winter bees. Possible interactions between immune response and physiological activity were tested by measuring the expression of vitellogenin and methyl farnesoate epoxidase, a gene coding for the last enzyme involved in juvenile hormone biosynthesis. Our data show that high DWV loads in winter bees correlate with reduced expression of genes involved in the cellular immune response and physiological activity and high expression of humoral immune genes involved in antibacterial defense compared with summer bees. This expression pattern could reflect evolutionary adaptations to resist bacterial pathogens and economize energy during the winter under a pathogen landscape with reduced risk of pathogenic viral infections. The outbreak of Varroa destructor infestation could have overcome these adaptations by promoting the transmission of viruses. Our results suggest that reduced cellular immune function during the winter may have increased honey bee's susceptibility to DWV. These results contribute to our understanding of honey bee colony losses in temperate regions.