Search Results (63)

Cuticular proteins (CPs)—key components of the insect exoskeleton—not only regulate development but also serve as structural barriers that enhance resistance against environmental stressors. This study identified CP gene families in Apis mellifera and analyzed their expression patterns during the worker capped brood development stages from mature larva to pre-eclosion. Using a comprehensive genome-wide bioinformatic approach, we identified 85 CP genes in A. mellifera which comprise six families: CPR (n = 43), CPAPs (n = 27), CPF (n = 2), Tweedle (n = 2), CPLCP (n = 8) and Apidermin (n = 3). Analysis of CP gene evolutionary relationship revealed that each CP family forms a distinct, relatively independent clade. Domain and motif analyses confirmed that all CPR members harbor a conserved Chitin_Bind_4 domain, consistent with CPR family structures in other taxa. Additionally, CPAP members possess one or three Chitin-binding Peritrophin-A domain (CBM_14), CPF members possess a conserved Pupal cuticle protein C1 domain (Cuticle_3), and Tweedle members contain a conserved domain of unknown function (DUF243). In addition, the analysis found no conserved domain within the CPLCP and Apidermin families. RNA-seq data revealed dynamic expression patterns of AmCPs during pupal development, with each gene family displaying a relatively characteristic temporal profile. Quantitative PCR validation of eight highly expressed CPR genes at 9 days post-capping confirmed the RNA-seq results. This work provides a comprehensive bioinformatic characterization and transcriptional analysis of CP genes in A. mellifera, offering a foundation for future functional studies on cuticle formation and identifying candidate genes potentially involved in cuticle development in honeybees. This work relies on transcriptomic data and in silico analyses. All proposed biological roles are hypothetical and require experimental validation. Full article

Honey bees (Apis mellifera L.) are considered highly significant economic insects. It is a source of valuable food and medicinal products such as honey, bee pollen, royal jelly, bee brood, and beeswax, which possess excellent nutritional and pharmacological properties. Nevertheless, honey bee health and productivity were often challenged by various environmental factors. Therefore, bee colony management is of the utmost importance. In this light, bee supplements and gut microbiota are crucial to ensure that bees receive sufficient nutritional value to maintain their health and productivity. In this study, we isolate and characterize lactic acid bacteria from the hindgut of the worker bee. 16S rRNA sequencing revealed that three isolated bacteria were Apilactobacillus kunkeei (AK), Lactiplantibacillus sp. (LP), and Lactobacillus brevis (LB). Three species of lactic acid bacteria were investigated for potential probiotic properties by supplementing 50% (w/w) sucrose syrup in the form of a direct-fed microorganism (DFM). The supplement with DFM had no negative effect on average lifespan. Examination took place of the impact of probiotics on the development of the hypopharyngeal glands (HPGs) in the bee’s head at days 3, 6, and 9 post-treatments. The cage-bees fed by pollen and DFM syrup exhibited acini surface areas ranging from 0.020 to 0.023 mm². The L. brevis (LB) group exhibited enhanced HPG development, with an average acini size of 0.027 ± 0.007 mm² at day 6, while the non-treatment control had an average acini size of 0.023 ± 0.006 mm². The significant size differences were maintained throughout the 9-day period. In addition, the DFM syrup enhanced microbial protein content in the bee head, digestibility, and community complexity compared with the negative control groups. Therefore, the DFM syrup with a potential strain of probiotic may enhance overall honey bee health status. Full article

Nestmate recognition is the primary defense mechanism maintaining the integrity of eusocial insect colonies. While social parasitism is widespread in Hymenoptera, it is rarely documented in termites, and the behavioral boundaries preventing interspecific infiltration remain poorly understood. Here, we investigated the potential for interspecific integration between two closely related termite species under laboratory conditions. We introduced Reticulitermes labralis workers and reproductives (queens and kings) into orphaned groups of R. aculabialis. We found that host workers exhibited caste-dependent aggression: introduced workers were immediately attacked and eliminated, whereas alien reproductives were partially tolerated. Surviving alien reproductives successfully integrated into host group, receiving allogrooming and trophallactic care from host workers. Crucially, these integrated pairs produced viable eggs and larvae. Molecular analysis confirmed that the brood reared by the host workers were the genetic offspring of the introduced R. labralis pair, demonstrating successful “cuckoo-like” reproduction. These findings reveal that termite colony recognition is sufficiently flexible to permit the acceptance of heterospecific reproductives when native royals are absent. While field evidence remains to be discovered, our results demonstrate that the behavioral and physiological prerequisites for social parasitism exist in termites, supporting the hypothesis that close phylogenetic relatedness (Emery’s rule) facilitates the breach of social barriers. Full article

The queen, as the reproductive core of a honeybee colony, has declining reproductive capacity with age, making it necessary to rear new queens to replace older ones. Traditional artificial queen-rearing methods face challenges, such as difficulties in larval grafting, particularly for Apis cerana. To address these issues, we developed a queen-rearing technology by cutting the comb. This study compared queen-rearing technology using comb cutting (CC) with larval grafting in A. cerana, measuring egg traits (length, width, weight), capped brood number, worker offspring initial weight, forager honey sac weight, worker morphology traits, and colony foraging efficiency. Queens reared using comb-cutting technology exhibited superior egg quality compared with those reared by larval grafting. The CC group showed significant improvements in egg length, egg weight, and number of capped brood cells (p < 0.05). Worker offspring from the CC group demonstrated significantly superior morphological traits—including forewing length, hindwing width, and lengths of the third and fourth tergites—as well as higher daily colony foraging activity, compared with those from the grafting larvae group (p < 0.05). Queen-rearing technology using CC effectively enhances the reproductive capacity and productive performance of colonies, promising high-quality queen rearing in A. cerana and sustainable beekeeping optimization. Full article

Stingless bees, particularly Tetragonula pagdeni, are vital for both ecosystems and the economy due to their pollination services and nest products. However, little is known about their nesting habits. This study investigated the nesting ecology of Tetragonula pagdeni in West Bengal, India. The species was found inhabiting a variety of landscapes, including agricultural, forest, rural, semi-urban, and urban areas, with a greater abundance in rural areas featuring mixed vegetation. Colonies, which were eusocial, perennial, and cavity-nesting, occupied diverse substrates, including tree trunks, building walls, rock crevices, electric poles, and field ridges—tree trunks and walls being the most common. Wild nests were located at heights ranging from 0 to 13.46 m, mostly around 2 m. Nest entrances varied in shape (circular, oval, slit-like, or irregular), with a longest opening axis of 10.50 ± 2.94 mm, and were oriented in multiple directions. Internally, nests measured 198.31 ± 86.36 mm in length and 142.73 ± 17.28 mm in width. Nests featured brood zones surrounded by honey and pollen pots, along with structure-supporting elements like the involucra and pillars. Brood cells were light brown and oval; those for workers and drones were similar, while queen cells were larger. Honey pots were light to dark brown, oval, dome-shaped, or irregular. Each involucrum was a thin, flat sheet, and the pillar was short, narrow, thread-like. These findings offer valuable insights into the distribution, nesting behaviour, and nest architecture of Tetragonula pagdeni, supporting its conservation and sustainable management. Full article

Dearth periods associated with less floral resources negatively impact Apis mellifera colony performance. Artificial diets offer nutritional supplements to sustain bee colonies under stressful conditions. An eight-week feeding trial was conducted using various artificial diets (eight diets, including a control diet), formulated with varying quantities of pulses, yeast, fenugreek powder, vegetable oil, dry apricot powder, and powdered sugar. Colony performance of bees subjected to different artificial diets was evaluated based on diet consumption, brood area, adult bee population, worker bee longevity, honey production, and enzymatic activity. Diet-7, which uniquely combined lupin, mung bean, and chickpea flours, proved the most efficacious and was the most consumed diet (84.29 ± 1.61 g), while diet-1 showed the lowest consumption (35.30 ± 1.08 g). Maximum brood area was recorded in colonies which were offered diet-7 (1385.95 ± 14.91 cm²), followed by diet-6, whereas the lowest was observed in the control (831.03 ± 18.95 cm²). The adult bee population was highest in diet-7 (21,594.50 ± 94.55 bees/hive), while lowest in the control (diet-0) (12,625.43 ± 385.06 bees/hive). Worker bee longevity was greatest in diet-7 (49.40 ± 0.41 days) and lowest in the control group (37.01 ± 0.39 days). Honey production was also highest in diet-7 (8.86 ± 0.21 kg), while lowest in the control (2.79 ± 0.35 kg). The results further showed that the enzymatic activities of bees were significantly improved due to diet-7, with the highest values for amylase (48.62 ± 0.23 U/mg), lipase (16.85 ± 0.20 U/mg), proteinase (25.21 ± 0.18 U/mg), and α-glucosidase (39.21 ± 0.21 U/mg). In conclusion, statistical analyses confirmed that diet-7 emerged as the most effective artificial diet, enhancing colony performance across all evaluated parameters. Future research should aim to optimize diet formulations and evaluate their effectiveness on colony health, including gut microbiome and immune function, across different seasons and ecological regions. Full article

Honeybees (Apis mellifera ligustica Spin.) are the most significant pollinating insects, playing a vital role in maintaining biodiversity. In healthy colonies, the reproductive success of the queen and the genetic contribution of drones are essential for long-term survival, directly affecting brood production, genetic diversity, and environmental adaptability. While the physiological and behavioral impacts of chemical pesticides on worker bees are relatively well documented, the risks to reproductive bees (queens and drones) remain poorly understood. In this study, we comprehensively assessed the effects of the widely used neonicotinoid thiamethoxam on the key developmental and physiological parameters in reproductive bees, including survival, pupation rate, eclosion rate, hormone titers, and detoxification enzyme activities. Our finding reveals that thiamethoxam exerts sublethal effects on larvae, significantly impairing the fitness of reproductive bees. Specifically, exposure altered juvenile hormone III, ecdysone titer, and acetylcholinesterase activity in reproductive larvae, with these effects showing a negative correlation with pesticide concentration. Notably, CYP450 activity exhibits a biphasic dose–response, with an initial elevation followed by a decline after reaching peak levels. These results demonstrate that thiamethoxam adversely affects the growth and development of reproductive bees, potentially compromising colony stability. By elucidating these sublethal effects, our study provides critical insights for mitigating pesticide-related threats to honeybee health. Our findings may help to scientifically and rationally avoid the potential risks of chemical pesticides to honeybees. Full article

This study investigated the effects of preheat hardening on the egg-laying capacity of honeybee queens and the flight performance of their daughter workers. A honeybee queen was confined in a cage with a two-section frame for 12 h. Then, 48 h old eggs from one section were incubated for 15 min at 41 °C and 70% relative humidity (RH). The queens (n = 12) raised in this section were named the pre-heat-treated queens (pH-TQs). Eggs from the second section were exposed to 34.5 °C and 70% RH for 15 min, and the queens raised in this section were named the non-heat-treated queens (nH-TQs) (n = 12). After mating, both groups were introduced to queenless hives in order to produce workers. The results show that, during the study period (2021 and 2022), the colonies headed by the pH-TQs reared significantly more brood cells and worker adults (especially during the summer), collected and stored more pollen, had less tendency to rear drone brood, and constructed fewer swarm cells than the colonies headed by the nH-TQs. Preheat hardening can be a promising method for improving honeybee workers’ reproductive potential and adaptability, allowing for better adaptation to environmental changes, thus compensating for the mass fatalities of honeybees globally. Full article

Effective control of the parasitic mite Varroa destructor in honey bee (Apis mellifera) colonies relies on integrated pest management (IPM) strategies to prevent mite populations from reaching economic injury levels. Formulations of oxalic acid combined with glycerin may provide a viable summer treatment option in continental Northern climates. This study evaluated the efficacy of oxalic acid and glycerin strips compared to oxalic acid dribble and 65% formic acid when applied in mid-August. Mite levels and colony health parameters were assessed, and honey samples from oxalic acid-treated colonies were analyzed for residue levels. Results showed that the oxalic acid and glycerin strips had a moderate acaricidal efficacy (55.8 ± 3.2%), which was significantly higher than those of 65% formic acid (42.6 ± 3.2%) and oxalic acid dribble (39.5 ± 4.3%), which did not differ between them, suggesting potential for summer mite control. No significant adverse effects on cluster size, worker mortality, queen status, or colony survival were observed. Oxalic acid and glycerin increased the proportion of spotty brood patterns at early timepoints after treatment, but recovery was noted after 45 days of starting the treatment. Similar effects on brood were observed with 65% formic acid 14 days after starting the treatment, with recovery by 28 and 45 days after starting the treatment. No significant differences in oxalic acid residues in honey from the control and treatment colonies were found. Oxalic acid and glycerin strips might help control varroa mite populations, delaying their exponential growth and helping reduce economic losses for beekeepers, but this treatment should be considered as part of an IPM strategy and not a stand-alone method for V. destructor control. Full article

Exposing insects to mild and/or severe heat can protect them from future heat stress by regulating the expression of certain stress markers. In this study, 60 queen larvae, one day old, were divided into the following two groups: a control group of non-heat-treated mother queens (nH-T MQ) kept for 15 min at 34.5 °C and 70% relative humidity (RH) and a pre-heat-treated mother queen group (pH-T MQ) that was kept for 15 min at 41 °C and 70% RH. Then, 500 daughter workers were collected from brood combs of each group and incubated at room temperature (22 °C) for 30 min, then divided into five groups (n = 100); each group was incubated for one hour at 35, 40, 45, 50, and 55 °C, respectively. The expression levels of several antioxidant genes and markers in 10 workers of each treatment were assessed by relative quantitative Real-Time qPCR and/or ELISA. The pH-T MQ showed improved basal and dynamic expression of several genes and enzymes, which indicated a protective response against heat stress and the effectiveness of tissue hardening on the biological process and/or mechanisms in oxidative stress and antioxidant activity response. These recorded changes may have global implications by improving thermotolerance acquisition during heat stress conditions. Full article

This study specifically examines the post-reproductive lifespan and ovarian activation in honeybee workers (Apis mellifera) with differing life expectancies. Drawing on the “grandmother hypothesis”, which postulates that older females enhance the survival and reproductive success of their descendants, we aimed to determine if similar patterns exist in eusocial insects. We conducted an experiment with newly emerged honeybee workers, dividing them into two groups: an untreated control group and an injured group with shortened lifespans due to thorax puncturing. The workers were monitored in an experimental apiary, and observations regarding ovarian development and hypopharyngeal gland size were recorded at various age intervals. Our results demonstrated a significant difference in lifespan between the control and injured bees, with injured individuals living notably shorter lives. The size of the hypopharyngeal gland, crucial for brood food production, varied significantly with respect to age and treatment, suggesting that physical injuries adversely affected physiological development. More intriguingly, our findings indicated that older honeybee workers displayed reduced ovarian activation, implying a potential reproductive cessation. This phenomenon can be interpreted as a form of menopause, which represents a strategic shift in energy investment from personal reproduction toward contributing to the colony as older individuals age. Full article

Melanin is an important component of the body color of honeybees, and its formation changes with the age of a capped brood of bees. However, up to now, the regulatory mechanism of melanin formation in honeybees remains unclear. To analyze the differential expression profile of microRNAs (miRNAs) in worker bees of Apis mellifera and to reveal the regulatory roles of differentially expressed miRNAs (DEmiRNAs) and mRNAs in the formation process of melanin during the capped brood stage, we used sRNA-seq technology and related software to analyze samples from four key developmental stages during the capped brood stage, when body color develops in Apis mellifera, namely, mature larvae (L0), pre-pupae (PP3), early pupae (P6) and mid-pupae (P9). A total of 1291 miRNAs were identified by bioinformatics. Three comparison groups were analyzed: L0 vs. PP3, PP3 vs. P6, and P6 vs. P9. A total of 171, 94, and 19 DEmiRNAs were identified in these groups, respectively, which regulate 1481, 690, and 182 differentially expressed target mRNAs (target DEmRNAs). The functional analysis of target DEmRNAs indicated that DEmiRNAs might regulate the formation of capped brood melanin in honeybees by activating expression changes in key genes in signaling pathways, such as the Wnt signaling pathway, melanogenesis, and the Toll and Imd signaling pathway, through activating miR-315-x, miR-8, ple, yellow family genes, wnt1, etc. Our research provides a theoretical basis for future analysis of the regulatory role of miRNAs in the formation of melanin in honeybees. Full article

P450 enzymes are integral to insect physiology, metabolism, hormone regulation, and adaptation to environmental challenges. By leveraging transcriptomic and genomic data, this study characterized the expression of 68 unique P450 genes across developmental stages and castes in the red imported fire ant (Solenopsis invicta), uncovering stage- and caste-specific differential expression patterns. Genes from the CYP4, CYP6, and CYP9 families, known for metabolizing exogenous and endogenous compounds, were highly expressed in early larval stages and minim workers, underscoring their roles in supporting rapid growth, hormone metabolism, colony maintenance, and brood care. The overexpression of CYP4AA1—linked to pheromone production—in queens, female alates, and female alate pupae highlights its critical functions in reproductive dominance, social structure maintenance, and colony dynamics. Here, juvenile hormone biosynthesis genes, including CYP305A1 and CYP315A1, exhibited significant overexpression in later instar larvae and larger workers, emphasizing their roles in development and in fulfilling colony-wide physiological demands. The “Halloween genes” (CYP302A1, CYP306A1, CYP315A1, CYP307A1, and CYP314A1) and CYP18A1 demonstrated dynamic regulation across developmental stages and castes, reflecting their essential contributions to hormonal production and balance throughout S. invicta’s lifecycle. These findings offer valuable insights into the molecular and biological mechanisms driving S. invicta’s social organization, developmental transitions, physiological adaptations, and evolutionary success. They also provide a foundation for future research into the regulatory pathways governing P450 gene expression and function. Full article

The honeybee comb serves as the primary site for all essential colony activities, and its structural and functional integrity plays a crucial role in colony development. As combs age through successive brood-rearing cycles, their physicochemical properties undergo significant changes, which can negatively affect colony health and productivity. This review synthesizes the current knowledge on the biological functions of combs, the aging process, and the negative impacts of old combs on cell structure, worker morphology, colony strength, and bee product quality. Additionally, it examines the adaptive strategies employed by honeybees and the recommended beekeeping management practices to mitigate these effects. Specifically, old combs undergo structural changes in cell dimensions and reduced spatial capacity, leading to the growth of smaller bees with diminished foraging and productivity. Furthermore, bee products, such as honey and beeswax, collected from old combs demonstrate compromised quality and higher levels of environmental contaminants. To counteract these challenges, colonies engage in hygienic behaviors, such as cell cleaning and comb rebuilding, while their enhanced immune and detoxification systems help mitigate comb-derived stressors. This review demonstrates that the systematic replacement of old brood combs is a critical management strategy to optimize bee health and ensure sustainable apiculture. Full article

The size of comb cells is a key factor influencing the body size of honey bee workers. Comb cells and the body size of Chinese honey bee workers are smaller than those of Italian honey bee workers. To increase the size of Chinese honey bee workers, this study used newly built combs from Chinese honey bee colonies (control group) and Italian honey bee colonies (treatment group). These combs were provided to Chinese honey bee colonies for queens to lay fertilized eggs with the aim of rearing larger workers. Workers emerging from the control and treatment combs were designated as control and treatment workers, respectively. We compared 13 external morphological traits, including right forewing length and width; linear length of veins a, b, c, and d; proboscis length; right hind femur length; tibia length; metatarsal length and width; and the longitudinal diameters of the third and fourth tergites between the two groups. The results identified six types of cell contents in the combs, excluding empty cells: capped honey (most abundant), followed by capped brood, uncapped honey, and smaller amounts of pollen, larvae, and eggs. Additionally, the average body weights of 6-day-old worker bee larvae, white-eyed pupae, adult worker bees, and honey stomachs containing sucrose solution were significantly higher in the treatment group than in the control group. Except for proboscis length, the average size of 12 out of 13 traits in the treatment group was significantly larger than in the control group, indicating that increasing cell size can produce larger Chinese honey bee workers. In the control group, only the left forewing was significantly shorter than the right, with no significant side-to-side differences in the other morphological traits. In the treatment group, the left forewing width, hind leg femur length, tibia length, and hind leg metatarsus width were significantly smaller than their right-side counterparts, while the other six traits showed no significant side-to-side differences. These findings provide a basis for using Italian honey bee combs to rear larger workers in Chinese honey bee colonies, offering beekeepers a strategy to enhance foraging capacity and improve honey production. Full article