Africanized Honey Bees Research Articles

Phenotypic and genetic characterization of Africanized Apis mellifera colonies with natural tolerance to Varroa destructor and contrasting defensive behavior.

Africanized Apis mellifera colonies with promising characteristics for beekeeping have been detected in northern Argentina (subtropical climate) and are considered of interest for breeding programs. Integral evaluation of this feral material revealed high colony strength and resistance/tolerance to brood diseases. However, these Africanized honeybees (AHB) also showed variable negative behavioral traits for beekeeping, such as defensiveness, tendency to swarm and avoidance behavior. We developed a protocol for the selection of AHB stocks based on defensive behavior and characterized contrasting colonies for this trait using NGS technologies. For this purpose, population and behavioral parameters were surveyed throughout a beekeeping season in nine daughter colonies obtained from a mother colony (A1 mitochondrial haplotype) with valuable characteristics (tolerance to the mite Varroa destructor, high colony strength and low defensiveness). A Defensive Behavior Index was developed and tested in the colonies under study. Mother and two daughter colonies displaying contrasting defensive behavior were analyzed by ddRADseq. High-quality DNA samples were obtained from 16 workers of each colony. Six pooled samples, including two replicates of each of the three colonies, were processed. A total of 12,971 SNPs were detected against the reference genome of A. mellifera, 142 of which showed significant differences between colonies. We detected SNPs in coding regions, lncRNA, miRNA, rRNA, tRNA, among others. From the original data set, we also identified 647 SNPs located in protein-coding regions, 128 of which are related to 21 genes previously associated with defensive behavior, such as dop3 and dopR2, CaMKII and ADAR, obp9 and obp10, and members of the 5-HT family. We discuss the obtained results by considering the influence of polyandry and paternal lineages on the defensive behavior in AHB and provide baseline information to use this innovative molecular approach, ddRADseq, to assist in the selection and evaluation of honey bee stocks showing low defensive behavior for commercial uses.

Effects of simulated tropical heat waves during development on the morphological and reproductive traits of Africanized honey bee

Effects of simulated tropical heat waves during development on the morphological and reproductive traits of Africanized honey bee

The Genomic Basis of Adaptation to High Elevations in Africanized Honey Bees.

A range of different genetic architectures underpin local adaptation in nature. Honey bees (Apis mellifera) in the Eastern African Mountains harbor high frequencies of two chromosomal inversions that likely govern adaptation to this high-elevation habitat. In the Americas, honey bees are hybrids of European and African ancestries and adaptation to latitudinal variation in climate correlates with the proportion of these ancestries across the genome. It is unknown which, if either, of these forms of genetic variation governs adaptation in honey bees living at high elevations in the Americas. Here, we performed whole-genome sequencing of 29 honey bees from both high- and low-elevation populations in Colombia. Analysis of genetic ancestry indicated that both populations were predominantly of African ancestry, but the East African inversions were not detected. However, individuals in the higher elevation population had significantly higher proportions of European ancestry, likely reflecting local adaptation. Several genomic regions exhibited particularly high differentiation between highland and lowland bees, containing candidate loci for local adaptation. Genes that were highly differentiated between highland and lowland populations were enriched for functions related to reproduction and sperm competition. Furthermore, variation in levels of European ancestry across the genome was correlated between populations of honey bees in the highland population and populations at higher latitudes in South America. The results are consistent with the hypothesis that adaptation to both latitude and elevation in these hybrid honey bees are mediated by variation in ancestry at many loci across the genome.

Effect of Improved Hive Cover Designs on Internal Microclimate and Colony Establishment of West African Honeybees (Apis mellifera adansonii L.) in Awka, Nigeria

Hive cover designs majorly affects the microclimate and colony establishment of African honeybee colonies in Nigeria. It became pertinent therefore to assess the effect of modified hive cover designs on the internal microclimate and colony establishment of West African honeybee (Apis mellifera adansonii L.) Colonies in Awka, Nigeria. Four insulating materials were used to construct the covers of twelve modified frame bar hives and designated: Control (plywood); T1 (warped boards); T2 (PVC) and T3 (foam). Each hive treatment was replicated three times. Data on ambient and hive microclimate as well as the colonization of honeybees’ colonies were observed and reported. The results indicated that the control had the highest temperature (31.86 ºC) while T1 (30.40ºC) had the least. The hive temperature was higher in March, 2023 (32.72°C) while August (29.87°C) had the least. The highest relative humidity (73.18%) was recorded in T1 while the control had the least (64.38%). The hive temperature and relative humidity was significantly affected by hive cover designs and different months of the study period (P<0.05). The highest colonization by African honeybees was observed in the control (100%) but none occurred in T2 (0.00%). Colonization of the Control hives occurred in July, October, and November, 2022 while that of T1 and T3 occurred in December, 2022. Colony establishment of African honeybees was not significantly affected by hive cover designs (p=0.26) and different months of the study period (p=0.24). It was concluded that beekeepers should adopt the insulation of hiver covers with plywood wood since it had 100% colonization of West African honeybees’.

Impact of acute oral exposure to paraquat and glyphosate on food consumption and survival rates of the African honeybee Apis mellifera scutellata Lepeletier (Hymenoptera: Apidae)

Impact of acute oral exposure to paraquat and glyphosate on food consumption and survival rates of the African honeybee Apis mellifera scutellata Lepeletier (Hymenoptera: Apidae)

Selectivity of fungi used in pest control to Africanized Apis mellifera L. (Hymenoptera: Apidae)

Side effects of fungi used for pest control on Apis mellifera, such as longevity and behavior should be made because these bees are beneficial to pollination. The objective was to evaluate the effects of commercial biological products, based on fungi, on the longevity and displacement behavior of Africanized bees A. mellifera. Different bioassays were carried out: 1) Ingestion of products; 2) Topical application by spraying; 3) Insect contact with the treated surface; 4) Residual effect and behavior analysis. The treatments were Control (distilled water), Beauveria bassiana; Isaria fumosorosea; Metarhizium anisopliae and Trichoderma harzianum. In bioassay 1, B. bassiana was the product that most reduced the longevity of bees by 39% after 168 h of evaluation. In bioassay 2, the product I. fumosorosea reduced the survival of bees, where only 5% of the bees were alive after 68 h. The other treatments did not affect the survival of A. mellifera workers. In bioassay 3, there was a reduction in the survival of worker bees of A. mellifera, from treatments B. bassiana and I. fumosorosea, after 168 h. These two products showed residual effects three and six days after application. In the vertical displacement, none of the products interfered, in the fall, all the products interfered. And in walking, no treatment interfered with the evaluated parameters. Of the tested fungi in the laboratory, T. harzianum was the selective fungus, for the Africanized A. mellifera workers, being considered safe. The other fungi were less selective in laboratory bioassays on Africanized A. mellifera workers.

Interactions between integrated pest management, pollinator supplementation, and normalized difference vegetation index in pumpkin, Cucurbita maxima (Cucurbitales: Cucurbitaceae), production.

Sustainable production of pumpkin (Cucurbita maxima Duchesne) partly relies on integrated pest management (IPM) and pollination services. A farmer-managed field study was carried out in Yatta and Masinga Sub-Counties of Machakos County, Kenya, to determine the effectiveness of a recommended IPM package and its interaction with stingless bee colonies (Hypotrigona sp.) for pollinator supplementation (PS). The IPM package comprised Lynfield traps with cuelure laced with the organophosphate malathion, sprays of Metarhizium anisopliae (Mechnikoff) Sorokin isolate ICIPE 69, the most widely used fungal biopesticide in sub-Saharan Africa, and protein baits incorporating spinosad. Four treatments-IPM, PS, integrated pest and pollinator management (which combined IPM and PS), and control-were replicated 4 times. The experiment was conducted in 600 m2 farms in 2 normalized difference vegetation index (NDVI) classes during 2 growing seasons (October 2019-March 2020 and March-July 2020). Fruits showing signs of infestation were incubated for emergence, fruit fly trap catches were counted weekly, and physiologically mature fruits were harvested. There was no effect of IPM, PS, and NDVI on yield across seasons. This study revealed no synergistic effect between IPM and PS in suppressing Tephritid fruit fly population densities and damage. Hypotrigona sp. is not an efficient pollinator of pumpkin. Therefore, we recommend testing other African stingless bees in pumpkin production systems for better pollination services and improved yields.

The Fungus Nosema ceranae and a Sublethal Dose of the Neonicotinoid Insecticide Thiamethoxam Differentially Affected the Health and Immunity of Africanized Honey Bees.

Honey bees (Apis mellifera L.) are affected by different biotic and abiotic stressors, such as the fungus Nosema ceranae and neonicotinoid insecticides, that negatively impact their health. However, most studies so far conducted have focused on the effect of these stressors separately and in European honey bees. Therefore, this study was conducted to analyze the impact of both stressors, singly and in combination, on honey bees of African descent that have demonstrated resistance to parasites and pesticides. Africanized honey bees (AHBs, Apis mellifera scutellata Lepeletier) were inoculated with N. ceranae (1 × 105 spores/bee) and/or chronically exposed for 18 days to a sublethal dose of thiamethoxam (0.025 ng/bee) to evaluate their single and combined effects on food consumption, survivorship, N. ceranae infection, and immunity at the cellular and humoral levels. No significant effects by any of the stressors were found for food consumption. However, thiamethoxam was the main stressor associated to a significant decrease in AHB survivorship, whereas N. ceranae was the main stressor affecting their humoral immune response by upregulating the expression of the gene AmHym-1. Additionally, both stressors, separately and combined, significantly decreased the concentration of haemocytes in the haemolymph of the bees. These findings indicate that N. ceranae and thiamethoxam differentially affect the lifespan and immunity of AHBs and do not seem to have synergistic effects when AHBs are simultaneously exposed to both stressors.

Bee species newly recorded for the Moroccan fauna, including two new species of Ammobatoides and Thyreus (Hymenoptera: Anthophila)

Summary Morocco has a large and species-rich bee fauna, but due to its large size and diversity of habitats, it remains understudied. Expeditions during 2022 discovered 16 new species for the country, including several very rarely collected or poorly studied taxa. The female of Thyreus mauretaniensis (Strand, 1911) is described for the first time, and Melitturga (Australomelitturga) rubricata Morice, 1916 is rediscovered and confirmed as a valid species; a female specimen is designated as a neotype for this taxon. Additionally, two new species of brood parasitic bees were discovered: Ammobatoides schwarzi n. sp. is described from southern Morocco where it is probably the parasite of Melitturga (Australomelitturga) albescens Pérez, 1895, and Thyreus rasmonti n. sp. is described from south-western Morocco where it likely parasitises Anthophora (Paramegilla) species. Lasioglossum (Evylaeus) marginatum (Brullé, 1832) is confirmed as present in Morocco in the Middle Atlas. Additional data are presented on the ecology and taxonomy of poorly known species. These findings further emphasise the understudied nature of both the Moroccan and broader North African bee fauna.

Three decades of “Africanized” honey bees in California

“Africanized” honey bees (AHB) have been part of California's agricultural and natural landscapes for nearly three decades. Prior to their arrival in 1994, leading honey bee experts expressed concern over the potentially disastrous impact of AHB on California agriculture and public safety. Despite these concerns, the state's agricultural production has not been significantly impacted by AHB. However, some evidence suggests that the abundance of AHB in natural habitats can have negative consequences for native pollinators. At the same time, AHB may provide a genetic resource for improving managed honey bee health. We recommend updating the term “Africanized” honey bees to more accurately reflect their biology and to avoid unfortunate connotations.

Melissopalynological analysis and floral spectra of Apis mellifera scutellata Lepeletier bees in different agroecologies of southwest Ethiopia

The availability of bee forage limits honeybee productivity and is very important for beekeepers. Therefore, the current study aimed to identify the major botanical resources of honeybee, A. mellifera scutellata, in Southwest Ethiopia. Between October 2019 and October 2020, 69 group discussions (8–12 beekeepers), field observations, and pollen analysis were used to collect data. A total of 72 honey samples were collected from five districts at different seasons for pollen analysis. Most of the honey samples tested (93.06%) were multifloral, while 6.94% were monofloral. Melissopalynological analysis indicated that Eucalyptus camaldulensis (52.02%) was the predominant pollen type and is considered monofloral honey. Terminalia spp. (25.96%), Guizotia spp. (17.80%), and Bidens spp. (17.61%) were secondary pollen types and classified as multifloral honey. Terminalia spp., Guizotia spp., Vernonia spp., Bidens ssp., Plantago spp., and E. camaldulensis were pollen types recorded in honey samples in all agroecologies. Beekeepers ranked Schefflera abyssinica, Vernonia amygdalina, and Cordia africana as the first source of pollen and nectar for honeybees in highland, midland, and lowland, respectively. Additionally, V. amygdalina, Coffea arabica, Croton macrostachyus, and C. africana were commonly observed bee flora in all agroecologies. Honey bee management, such as bee forage shortages, the occurrence of brood and swarming, varied significantly (P < 0.05) among different agroecologies. In the present study, 53 honeybee plants were identified as pollen and nectar sources for honeybees. Various herbs (41.50%), trees (30.20%), and shrubs (28.30%) played a major role in honey production. Thus, beekeeping should be integrated with vegetation conservation for livelihood improvement and food security. Furthermore, existing bee flora should be cultivated in areas to increase the harvesting of honeybee products and improve the apiculture industry.

Residual effect of imidacloprid and beta-cyfluthrin on Africanized Apis mellifera L. (Hymenoptera: Apidae) workers

Residual effect of imidacloprid and beta-cyfluthrin on Africanized Apis mellifera L. (Hymenoptera: Apidae) workers

Recruitment Behaviour in an African Meliponine Bee Species (hymenoptera, Apidae: Meliponini): Understanding Glandular Origin and Pheromonal Components

Meliponine bees are speculated to use a variety of communication mechanisms to effectively recruit workers of a colony to collect sufficient amounts of food to nourish the entire nest population. Mechanisms used to convey such information include thoracic vibrations and trophallaxis within the nest; footprint secretions and pheromone marks deposited in the field, or a combination of these signals and cues. There have been numerous discrepancies about the origin of trail pheromone production from the head, thorax, abdomen and leg regions of meliponine bees. Because the glandular origin of pheromone marks deposited by African meliponine bee’s species has not yet been investigated, we first confirmed if these species actually carry out scent marking and recruitment behaviour at visited food sources. Secondly, we tested if either nasonov or tarsal gland secretions elicited trail-following behaviour in newly recruited bees by means of chemical and electro-physiological analyses as well as with bio-assays testing both natural extracts and synthetic pheromone compounds from both glands. Significant differences were observed in the foraging patterns of the four bee species on collected resources (nectar, pollen and water) as the synthetic compound, (E)-β-farnesene was significantly as attractive to foragers of the four species when compared to the natural nasonov gland extract. Our results showed a significantly higher proportion of foragers from the four species been attracted to food resources baited with natural extracts from their own glands and recruited additional foragers to such baited food sites.&#x0D; Keywords: Meliponine bee species, recruitment behaviour, nasonov glands, tarsal glands

Can the shape of the wing help in the identification of African stingless bee species? (Hymenoptera: Apidae: Meliponini)

Can the shape of the wing help in the identification of African stingless bee species? (Hymenoptera: Apidae: Meliponini)

Geometric Morphometric Analysis of Wing Shape to Identify Populations of Apis mellifera in Camagüey, Cuba.

A total of 45 Apis mellifera colonies were sampled from nine centers for rearing queens in the Camagüey province, Cuba. Wing geometric morphometric analysis was used to determine the ancestry and identify Africanization processes at different altitudes in managed honeybee populations on the island. A total of 350 reference wings were obtained from the pure subspecies: Apis mellifera mellifera, Apis mellifera carnica, Apis mellifera ligustica, Apis mellifera caucasia, Apis mellifera iberiensis, Apis mellifera intermissa, and Apis mellifera scutellata for the study. Our results showed that altitude influences wing shape; and that 96.0% (432) of the individuals were classified as Cuban hybrids, with a tendency to the formation of a new morphotype. In addition, a great similarity was found with the subspecies Apis mellifera mellifera, and it was confirmed that there is no Africanization due to the low presence of 0.44% (2) of this morphotype in the population under study. The greatest Mahalanobis distances were obtained for the comparisons between the center rearing of queens in the Camagüey province with the subspecies A. m. scutellata (D2 = 5.18); A. m. caucasia (D2 = 6.08); A. m. ligustica (D2 = 6.27); and A. m. carnica (D2 = 6.62). The well-defined pattern of wing shape produced by honeybee populations in Camagüey's centers for queen rearing suggests a Cuban hybrid. Moreover, it is essential to note that the populations of bees under investigation lack Africanized morphotypes, indicating that Camagüey bees have not interacted with the African lineage.

Neonicotinoid effects on tropical bees: Imidacloprid impairs innate appetitive responsiveness, learning and memory in the stingless bee Melipona quadrifasciata

Together with other anthropogenic factors, pesticides play a major role in pollinator decline worldwide. Most studies on their influence on pollinators have focused on honey bees given the suitability of this insect for controlled behavioral testing and raising. Yet, studies on pesticide impact should also contemplate tropical species, which contribute a major part of biodiversity and which have remained so far neglected. Here we focused on the stingless bee Melipona quadrifasciata and asked if the widely used neonicotinoid imidacloprid disrupts its learning and memory capabilities. We fed stingless bees with 0.1, 0.5 or 1 ng of imidacloprid, tested their innate appetitive responsiveness and trained them to associate odors and sucrose reward using the olfactory conditioning of the proboscis extension response. The same experiments were performed on Africanized honey bees. One hour after intoxication, both species decreased their innate responsiveness to sucrose but the effect was more accentuated in stingless bees. In both species, learning and memory were affected in a dose-dependent manner. These results indicate that pesticides have dramatic consequences on tropical bee species and claim for rational policies regulating their use in the tropics.

Effect of bee bread on Africanized honey bees infected with spores of Nosema spp.

Floral diversity allows honey bees, Apis mellifera L. (including its hybrids between subspecies) (Hymenoptera: Apidae), to meet their nutritional requirements. However, infection by Nosema spp. (Microsporidia: Nosematidae) destroys a bee's digestive epithelium, hindering the ability to absorb nutrients. In some subtropical regions, such as the Yucatan Peninsula, Mexico, nosemosis is one of the most widespread diseases in commercial apiaries. To date, there have been no reports of colony deaths attributable to the disease. It is possible that the naturally occurring diet in the Yucatan Peninsula sustains honey bee health. We tested this hypothesis by evaluating the effect of four diets – bee bread collected in the Yucatan's rainy and dry seasons, sucrose syrup, and a pollen substitute – on the response of caged Africanized honey bees (A. m. scutellata × A. m. adansonii × A. mellifera) to nosemosis infection (treatment with spores of Nosema apis Zander and Nosema ceranae Fries). We found that infected and uninfected bees consumed food in similar amounts regardless of the diet, although, overall, they fed at significantly lower rates when provided the pollen-substitute diet. Bees fed either of the bee bread diets had relatively low fat-body weight and expression of Vg, proPO, and GOx genes, three genes related to immune function. Bees fed sucrose syrup had low fat-body weight but relatively high gene expression. Infection from Nosema spores only reduced the individual survival probability for bees fed the bee bread collected in the dry season, yet bees fed the dry-season bee bread had the lowest infection rates. Our results indicate that natural stored bee bread in honey bee colonies from the Yucatan Peninsula could be one of the main factors influencing their survival and reducing Nosema spp. spore load.

Prospects, challenges and perspectives in harnessing natural selection to solve the 'varroa problem' of honey bees.

Honey bees, Apis mellifera, of European origin are major pollinators of crops and wild flora. Their endemic and exported populations are threatened by a variety of abiotic and biotic factors. Among the latter, the ectoparasitic mite Varroa destructor is the most important single cause behind colony mortality. The selection of mite resistance in honey bee populations has been deemed a more sustainable solution to its control than varroacidal treatments. Because natural selection has led to the survival of some European and African honey bee populations to V. destructor infestations, harnessing its principles has recently been highlighted as a more efficient way to provide honey bee lineages that survive infestations when compared with conventional selection on resistance traits against the parasite. However, the challenges and drawbacks of harnessing natural selection to solve the varroa problem have only been minimally addressed. We argue that failing to consider these issues could lead to counterproductive results, such as increased mite virulence, loss of genetic diversity reducing host resilience, population collapses or poor acceptance by beekeepers. Therefore, it appears timely to evaluate the prospects for the success of such programmes and the qualities of the populations obtained. After reviewing the approaches proposed in the literature and their outcomes, we consider their advantages and drawbacks and propose perspectives to overcome their limitations. In these considerations, we not only reflect on the theoretical aspects of host-parasite relationships but also on the currently largely neglected practical constraints, that is, the requirements for productive beekeeping, conservation or rewilding objectives. To optimize natural selection-based programmes towards these objectives, we suggest designs based on a combination of nature-driven phenotypic differentiation and human-directed selection of traits. Such a dual strategy aims at allowing field-realistic evolutionary approaches towards the survival of V. destructor infestations and the improvement of honey bee health.

Influence of Hive Cover Modifications and Ambient Microclimate on Colonization of African Honeybees in Awka, Nigeria

Poor colonization of hives by African honeybees is one of the constraints facing the beekeeping sector. This study aimed to determine the influence of some hive cover modifications on the colonization of African honeybees in Awka. The hive covers of top bar hives were modified by insulating them with different materials and grouped into four treatments, namely: T1 (plywood), T2 (warped boards), T3 (polyvinyl chloride ceiling material), and T4 (foam). At various months, data on the ambient microclimate (temperature and relative humidity) and the number of hives colonized per treatment were collected. The colonization rate was highest in treatment 1 (100%), followed by treatment 2 (33.33%) while treatments 3 and 4 (0.00%) had the least. Hive treatments did not significantly affect the colonization of honeybees (p = 0.09). Treatment 1 colonized in the months of July, October, and November, while that of Treatment 2 occurred in December. Months had significant effect on the mean colonization of African honeybees (p&lt;0.05). The mean colonization of hives and ambient temperature had a negative correlation while there was a positive correlation between the mean colonization of hives and ambient relative humidity. Hive covers insulated with ply wood were recommended since they achieved earlier colonization than other treatments.

Meta-analysis of genetic diversity and intercolony relatedness among reproductives in commercial honey bee populations.

Honey bee colonies are large kin groups, each with a single mother queen and thousands of female workers. Queen bees are highly polyandrous, each mating with an average of approximately 12 drones from other colonies. We used a meta-analysis approach to compare the pedigree relationships of honey bee reproductives (queens and their mates) across five different studies and to quantify the overall genetic diversity of breeding populations. We compared the inferred genotypes of queens and their mates from microsatellite analyses of worker offspring from a feral Africanized honey bee population (which served as a negative control for inbreeding), an experimentally derived population of sister queens (which served as a positive control for inbreeding), and three separate commercially managed populations. We then compared the relatedness of all drones mated to each queen (mate-mate), all queens within each population (queen-queen), each queen with each of her mates (queen-mate), and all drones within each population (drone-drone). We found, as expected, the lowest levels of genetic similarity in the outcrossed population and highest levels of genetic similarity in the inbred population. Levels of genetic similarity among the managed honey bee populations were intermediate but closer to that of the inbred population. Genetic structuring of the entire breeding population resulted in two major subpopulations, likely deriving from breeders on the east and west coast. The effects that these findings have on the overall population genetic diversity of managed honey bees is discussed.