Search Results (24)

Due to the ongoing global spread of the small hive beetle (SHB), Aethina tumida, there is a significant need for detection and practical management strategies against this pest. The standard inspection strategies for SHBs involve (1) detailed visual examination of the colony, which is challenging in areas with defensive bees, or (2) sampling beetles via traps, which requires repeated visits to the apiary and can be difficult for beekeepers with apiaries in rural areas. In this study, we modified the inspection sequence to examine the in-hive distribution of the beetle and assess whether a limited, yet targeted, inspection could provide valuable information on beetle infestation. We conducted our modified sampling in three different countries: Hawai’i (USA), Mexico, and Costa Rica. We found that targeted screening of the top areas of the hive (cover and top-side frames) provided reliable information about the relative prevalence of SHBs in a colony. The results also suggested that SHBs do not naturally congregate on a bare bottom board but migrate downward during inspection. Trap placement on the bottom floor of the hive may underestimate beetle presence in low to medium pest levels. The proposed inspection protocol is not influenced by the genetic origin of the bees (Africanized or European) and could be a practical alternative for assessing SHB infestation levels in honeybee colonies. Full article

The small hive beetle (SHB) was first detected in Italy in 2014 and remains confined to the regions of Calabria and Sicily (Italy). The environmental and colony-related factors favorable to the development of SHBs are widely studied, but mainly at the laboratory level; it is not yet clear whether these factors also apply in the field within apiaries in regions affected by SHBs. In 2022, we conducted a study in the province of Reggio Calabria, Italy, to investigate if these factors influence SHB infestation levels in honey bee colonies. Data were collected from 67 hives in late winter and 81 hives in autumn, inspecting each hive three times per season. Overall, SHB infestation levels were low (an average 0.83 SHB/hive). Our analysis revealed a significant relationship between the SHB infestation level and the following six factors: the number of combs covered by adult bees, the total number of combs, combs surveillance, the previous month’s infestation, sun exposure, and season. GLM analysis predicted a higher number of SHBs in colonies with fewer combs covered by adult bees (2.543), with a greater number of combs (1.877), with lower comb surveillance (0.935), with a higher SHB infestation level in the previous month (1.192), in shaded locations compared to sunny ones (0.207), and in autumn compared to late winter (0.258), with peak infestations in September. These findings provide insights to inform surveillance plans, optimise sentinel apiaries setup in SHB-free regions, and offer practical guidance for beekeepers on implementing biosecurity measures to minimise infestation levels and enhance early detection. Future research should examine whether these factors have similar effects in regions with higher SHB infestation rates. Full article

Aethinosis, the honey bee disease caused by small hive beetle, is listed in the Animal Health Law and requires mandatory surveillance and control measures. The Mobile Divider (MD) method has been proposed as a time-saving alternative to the official surveillance method outlined by the Ministry of Health (MoH). The current study aimed to evaluate the efficacy of the MD method in concentrating SHBs behind the MD and optimizing the number of SHBs detected during hive inspections, thereby improving the surveillance strategies required by European regulations and the WOAH. In late winter and autumn 2022, we conducted 431 hive inspections across six apiaries in the province of Reggio Calabria, Italy. A total of 379 adult SHBs were collected and killed; no larvae were detected. Using the MD method, 238 SHBs were found behind the MD, while 141 SHBs were found in the remaining volume of the hive. Chi-square analysis confirmed the effectiveness of the MD method, showing that the SHB distribution behind the MD and in the remaining volume of the hive was not random (p < 0.0005). Further studies are needed to assess the effectiveness and potential benefits of the MD method in regions with higher SHB infestation levels. Full article

Aethina tumida, commonly known as the small hive beetle, poses a threat to honeybee populations, particularly Apis mellifera, across several European regions. Originating in sub-Saharan Africa, there is a risk of the infestation spreading from Calabria, a region in the south of Italy. The essential role played by Apis spp. in pollination biodiversity preservation, agricultural productivity, and the overall economy is related to the dangers posed by the invasion of Aethina tumida. Current detection methods often fail to identify infestations early, leading to significant colony losses. We focused on creating a biosensor to improve the detection of Kodamaea ohmeri, a recently identified yeast that coexists symbiotically with Aethina tumida. The biosensor was designed to exploit the highly sensitive quartz crystal microbalance to identify a specific peptide linked to Kodamaea ohmeri in honey specimens. Its gold-plated surface over quartz was functionalized with an antibody effective in recognizing the peptide associated with Kodamaea ohmeri, a potential warning for detecting Aethina tumida. Preliminary results support the possibility of using such biosensor technology to detect infestation and enhance colony management techniques for honeybees, enabling beekeepers to implement prompt and focused treatments. In addition, reducing the size and cost of these biosensors and offering user training would be very helpful in having them used in beekeeping. Full article

Currently, there is no integrated pest management approach for controlling small hive beetles (Aethina tumida), a widespread honey bee (Apis mellifera) pest. To date, only hive trapping has shown any effectiveness in controlling the pest. In this study, we tested several possible active ingredients that have been shown previously to demonstrate low toxicity towards honey bees. To test their toxicities, we treated both SHBs and honey bees topically and exposed SHBs to these compounds orally via pollen. Coumaphos (industry standard), a solvent control (acetone), and a positive control (dimethoate) were used for comparisons. Thiacloprid (LD₅₀ = 1.3 ng/SHB; LC₅₀ = 12 µg/g pollen) was the most toxic active ingredient tested against SHBs both topically and through pollen. Topically, thiacloprid was 340× more toxic to SHBs than coumaphos (LD₅₀ = 431 ng/SHB). However, acetamiprid (selectivity ratio = 152) was much more toxic to SHBs than to honey bees compared to thiacloprid (selectivity ratio = 3). These findings demonstrate the need to find other active ingredients other than coumaphos and that acetamiprid has the greatest potential to reduce SHB populations safely in a honey bee hive. Field research using acetamiprid should be conducted to explore possible sub-lethal effects on honey bees. Full article

Beekeepers need new treatment options for controlling small hive beetles (Aethina tumida), a devastating honey bee (Apis mellifera) pest. For many years, commercial beekeepers in the U.S. have used gel roach baits off-label as a method for treating SHBs. Herein, we evaluated the acute toxicity of active ingredients commonly found in gel roach baits, including abamectin, clothianidin, hydramethylnon, fipronil, and indoxacarb through topical and oral routes of exposure against SHBs and honey bees. Additionally, coumaphos, the active ingredient of the only registered in-hive control treatment for SHBs, was evaluated to provide a comparison to the gel roach bait active ingredients. Fipronil was the most toxic compound to SHBs topically (LD₅₀ = 0.23 ng/SHB) and through pollen (LC₅₀ = 0.06 µg/g pollen). Fipronil (LD₅₀ = 0.31 ng/honey bee) had a selectivity ratio of 1.3, suggesting that it is more toxic to SHBs than it is to honey bees, but only to a small degree. Abamectin, clothianidin, hydramethylnon, and indoxacarb had a higher toxicity to honey bees than to SHBs through topical exposure. Our results suggest that gel roach baits and their active ingredients are toxic to honey bees and pose a serious risk to colony safety if used as in-hive treatments. Full article

Mexico is a major honey producer, but not much information exists about the health status of honey bees (Apis mellifera L.) in the country. This study was conducted to determine the sanitary status of adult honey bees in Mexico’s five beekeeping regions. Samples from 369 apiaries were diagnosed to identify pathogens such as Varroa destructor, which was quantified, Acarapis woodi, Nosema spp., and five viruses. Colonies were also inspected for the presence of the small hive beetle (SHB), Aethina tumida. Varroa destructor was found in 83.5% of the apiaries, with the Pacific Coast region having the highest prevalence (>95%) and rates (4.5% ± 0.6). Acarapis woodi was detected in only one apiary from the Pacific Coast, whereas Nosema spp. were prevalent in 48.5% of the apiaries, with the highest and lowest frequencies in the Yucatan Peninsula and North regions (64.6% and 10.2%, respectively). For viruses, deformed wing virus (DWV) was detected in 26.1% of the apiaries, with the highest frequency in the Pacific Coast region (44.7%). Israeli acute paralysis virus (IAPV) was diagnosed in 3.2% of the samples and sacbrood bee virus (SBV) in 23.3% of them, with the highest frequency in the High Plateau region (36.4%). Chronic bee paralysis and Kashmir bee viruses were not detected. SHB prevalence was 25.2% nationwide, with the highest frequency in the Yucatan Peninsula (39.2%). This study shows that the most common parasites of adult honey bees in Mexico are V. destructor and Nosema spp., and that the most prevalent virus is DWV, whereas SHB is highly prevalent in the Yucatan Peninsula. This information could be useful to design disease control strategies for honey bee colonies in different regions of Mexico. Full article

Beekeepers need new registered products to control the small hive beetle (SHB), Aethina tumida, a significant pest of western honey bee (Apis mellifera) colonies. Few approved chemical controls exist, and there is no standardized system for screening compounds against SHBs. We outline a detailed method for an acute toxicity bioassay that delivers compounds via pollen. We provide a detailed method for a field trial that delivers treated pollen in traps made from modified compact disc cases. We applied both methods in proof-of-concept experiments to assess acetamiprid as a SHB control agent. Using the laboratory bioassay, we found acetamiprid (${\mathrm{LC}}_{50}$ = 20.5 µg/g) to be more toxic to SHBs than coumaphos was (${\mathrm{LC}}_{50}$ = 1250 µg/g), yet less toxic to SHBs than fipronil was (${\mathrm{LC}}_{50}$ = 1.78 µg/g). In our field trial, colonies treated with acetamiprid and fipronil significantly reduced (p < 0.001) live SHB populations over those of control colonies. Traps containing acetamiprid retained significantly higher (p < 0.001) numbers of dead SHBs than did traps containing fipronil. We outline the first detailed methods to assess the toxicity of compounds delivered in pollen for adult SHB control. Our proof-of-concept experiments showed acetamiprid to be a promising control agent for SHBs. Full article

The exotic alien species Aethina tumida, commonly known as the small hive beetle (SHB), was first detected in the Italian region of Calabria in 2014. The SHB is endemic in sub-Saharan Africa and is established in North and Central America, Australia, and many other world regions. Little is known about the effects of SHB introduction in new regions. This article focuses on the economic and regulatory aspects of SHB invasions. It presents the results of a survey questionnaire administered to Italian bee experts and extension agents in the spring of 2019, which documents opinions about the SHB invasion and its management in Italy. The results show that the SHB and Varroa are perceived as major threats to bee health. Over half of respondents agree that SHB eradication is no longer an attainable policy objective in Calabria, and support a policy shift from eradication to control of SHBs. Among respondents, extension agents are the most likely to agree with the need for a policy adjustment. Additional scientific and economic evidence and analysis can help resolve the differences in the opinions of stakeholders about feasible or preferable management policies for the SHB, and crucially, ensure the participation of beekeepers in the surveillance and control efforts. Full article

Environmental DNA (eDNA) contained in honey derives from the organisms that directly and indirectly have been involved in the production process of this matrix and that have played a role in the hive ecosystems where the honey has been produced. In this study we set up PCR-based assays to detect the presence of DNA traces left in the honey by two damaging honey bee pests: the small hive beetle (Aethina tumida) and the greater wax moth (Galleria mellonella). DNA was extracted from 82 honey samples produced in Italy and amplified using two specific primer pairs that target the mitochondrial gene cytochrome oxidase I (COI) of A. tumida and two specific primer pairs that target the same gene in G. mellonella. The limit of detection was tested using sequential dilutions of the pest DNA. Only one honey sample produced in Calabria was positive for A. tumida whereas about 66% of all samples were positively amplified for G. mellonella. The use of honey eDNA could be important to establish early and effective measures to contain at the local (e.g., apiary) or regional scales these two damaging pests and, particularly for the small hive beetle, to prevent its widespread diffusion. Full article

The Small Hive Beetle (Aethina tumida Murray, 1867) is an invasive scavenger of honeybees. Originally endemic in sub-Saharan Africa, it is regulated internationally in order to preserve the areas still free from this species. To ensure the reliability of official diagnoses in case of introduction, an inter-laboratory comparison was organised on the identification of A. tumida by morphology and real-time PCR. Twenty-two National Reference Laboratories in Europe participated in the study and analysed 12 samples with adult coleopterans and insect larvae. The performance of the laboratories was evaluated in terms of sensitivity and specificity. Sensitivity was satisfactory for all the participants and both types of methods, thus fully meeting the diagnostic challenge of confirming all truly positive cases as positive. Two participants encountered specificity problems. For one, the anomaly was minor whereas, for the other, the issues concerned a larger number of results, especially real-time PCR, which probably were related to inexperience with this technique. The comparison demonstrated the reliability of official diagnosis, including the entire analytical process of A. tumida identification: from the first step of the analysis to the expression of opinions. The performed diagnostic tools, in parallel with field surveillance, are essential to managing A. tumida introduction. Full article

The small hive beetle (SHB), Aethina tumida was first detected in the Calabria and Sicily region (Southern Italy) in 2014. In this regard, a more effective and faster inspection method than the Official one (Ministry of Health) was tested to detect the beetle in the hive. In collaboration with Calabria beekeepers’ association, a “mobile divider”-based method was tested, in order to facilitate the detection of A. tumida and save time during hive inspection. In this short communication, we provide an update on the mobile divider technique and its related inspection procedure, which was first proposed and used in Calabria (Southern Italy) from 2014 to 2016. We report preliminary data concerning the number of detected SHBs and the time spent for their detection, based on the inspection of two apiaries in Calabria region, using both methods (official method and mobile divider method). The preliminary data presented here show that, on average, the mobile divider method seems to be able to recover a slightly higher number of beetles (0.9 adults) per inspected hive, in a shorter time (25 s). Full article

Cuticular hydrocarbons (CHCs) cover insects’ bodies and play important roles in chemical communication, including nestmate recognition, for social insects. To enter colonies of a social host species, parasites may acquire host-specific CHCs or covertly maintain their own CHC profile by lowering its quantity. However, the chemical profile of small hive beetles (SHBs), Aethina tumida, which are parasites of honey bee, Apis mellifera, colonies, and other bee nests, is currently unknown. Here, adults of SHB and honey bee host workers were collected from the same field colonies and their CHC profiles were analysed using GC-MS. The chemical profiles of field-sampled SHBs were also compared with those of host-naive beetles reared in the laboratory. Laboratory-reared SHBs differed in their CHC profiles from field-sampled ones, which showed a more similar, but ten-fold lower, generic host CHC profile compared to host workers. While the data confirm colony-specific CHCs of honey bee workers, the profile of field-collected SHBs was not colony-specific. Adult SHBs often commute between different host colonies, thereby possibly preventing the acquisition of a colony-specific CHC profiles. An ester was exclusive to both groups of SHBs and might constitute an intraspecific recognition cue. Our data suggest that SHBs do not use any finely tuned chemical strategy to conceal their presence inside host colonies and instead probably rely on their hard exoskeleton and defence behaviours. Full article

Aethina tumida is a parasite and predator of honeybee causing severe loss to the bee industry. No effective and environmentally friendly methods are available to control this pest at present. Chemosensory genes play key roles in insect behavior which can potentially be used as targets for developing environmentally friendly pest control agents. In this study, the putative chemosensory genes in antennae and forelegs of A. tumida involved in olfaction or contact chemical communication of adults were investigated using RNA transcriptome sequencing and PCR methods. Based on transcriptomic data, unigenes encoding 38 odorant receptors (ORs), 24 ionotropic receptors (IRs), 14 gustatory receptors (GRs), 3 sensory neuron membrane proteins (SNMPs), 29 odorant binding proteins (OBPs), and 22 chemosensory proteins (CSPs) were identified. The analyses of tissue expression profiles revealed that genes encoding 38 ORs, 13 antennal IRs, 11 GRs, 1 SNMP, 24 OBPs, and 12 CSPs were predominately expressed in antennae. No significant differences in expression levels of these genes were found between males and females. Genes encoding 5 non-NMDA iGluRs, 3 GRs, 2 SNMPs, 5 OBPs, and 12 CSPs were predominately expressed in forelegs. RT-PCR assays for SNMPs, OBPs and CSPs further revealed that 3 OBPs (AtumOBP3, 26 and 28) and 3 CSPs (AtumCSP7, 8 and 21) were highly expressed in antennae. Our results enrich the gene inventory of A. tumida and facilitate the discovery of potential novel targets for developing new pest control measures. Full article

The small hive beetle (Aethina tumida Murray) is a serious threat to beekeeping and crops that rely on honeybees for pollination. The small hive beetle not only causes significant damage to honeybees by feeding on pollen and honey, attacking bee brood and causing stored honey to ferment, but also might serve as a vector of diseases. In addition, the small hive beetle has developed resistance to the pyrethroid and organophosphate insecticides registered for control of honeybee pests in the United States. The development of resistance in small hive beetle populations is a great concern to the beekeeping industry; thus, there is an urgent need for strategies to manage that resistance. Therefore, we used synergist probes to determine the mechanisms of resistance in a small hive beetle population to these insecticides. Our studies on the toxicity of insecticides alone or with the synergists piperonyl butoxide (PBO) and S,S,S,-tributyl phosphorotrithionate (DEF) suggested that mixed-function oxidases and esterases were the major resistance factors to these insecticides in a studied population of the small hive beetle. In contrast, there was no synergism with diethyl maleate (DEM), triphenyl phosphate (TPP) and formamidine. Therefore, glutathione-S-transferase, carboxylesterase and target site were not involved in insecticide resistance in the small hive beetle. Rotation of classes of insecticides (with different modes of action) and metabolic synergists were suggested for the development of successful resistance management programs. To the best of our knowledge, this is the first study of the mechanisms of resistance in small hive beetle populations in Florida and suggests an urgent need for alternative control strategies for these serious pests of honeybee colonies. Full article