Honey Bee Subspecies Apis Mellifera Research Articles

Parasite and virus dynamics in the honeybee Apis mellifera unicolor on a tropical island recently invaded by Varroa destructor

In La Réunion, the established honeybee subspecies Apis mellifera unicolor, an endemic subspecies of African lineage, is facing considerable challenges. Since the introduction of the Varroa destructor mite in 2017 high colony losses have been recorded. We investigated the dynamics of V. destructor and two viruses, the Deformed Wing Virus (DWV), known to be transmitted by the mite, and the Chronic Bee Paralysis Virus (CBPV), in A. m. unicolor. Colonies from two apiaries located at 300 and 900 m a.s.l were monitored twice for one year without any acaricide treatment. The brood area, V. destructor infestation rates, DWV and CBPV prevalence and load were recorded monthly. A. m. unicolor maintained brood rearing throughout the year. Varroa destructor infestation resulted in high colony mortality (up to 85 %) and high phoretic mite rates (up to 52 mites per hundred bees). The establishment of DWV in colonies occurred after that of V. destructor and the mite infestation rate had a significant effect on the virus prevalence and load. CBPV appeared only transiently throughout the surveys. The data showed that, in tropical colonies with permanent brood rearing, V. destructor and DWV can reach high levels, but are still subject to seasonal variations that appear to be influenced by environmental conditions. This suggests that beekeeping practices could be adapted by favouring sites and periods for transhumance or acaricide treatment.

Procruste analysis of forewing shape in two endemic honeybee subspecies Apis mellifera intermissa and A. m. sahariensis from the Northwest of Algeria

Abstract. Abed F, Bachir-Bouiadjra B, Dahloum L, Yakubu A, Haddad A, Homrani A. 2021. Procruste analysis of forewing shape in two endemic honeybee subspecies Apis mellifera intermissa and A. m. sahariensis from the Northwest of Algeria. Biodiversitas 22: 154-164. Honey bees play an important role as pollinators of many crops. Thus they are collectively considered as a veritable economic source. The present study was undertaken to describe variation in the right forewing geometry in two Algerian honeybee subspecies Apis mellifera intermissa and Apis mellifera sahariensis using landmark-based geometric morphometrics. A total of 1286 honeybees were sampled from 12 provinces in the northwest of Algeria. The forewing geometry was evaluated using 20 homologous landmarks by applying Procrustes superimposition analysis. The top four principal components accounted for only 41.1% of wing shape variation between the two subspecies. There was a significant difference in wing shape between the two subspecies (Mahalanobis distance = 1.0626 ; P<0.001), whereas their wing size seemed similar (P>0.05). Regarding the allometric effect, the percentage of variation in wing shape explained by size changes was relatively small, with 1.28% and 4.37% for A. m. intermissa and A.m sahariensis, respectively. The cross-validation procedure correctly classified 68.3% of specimens into their original groups. PERMANOVA test revealed significant differences in the right forewing shape among all geographic areas studied (P<0.001). The results clearly showed that the landmark-based geometric approach applied to forewings venation is a powerful and reliable tool in the discrimination of native honey bee subspecies and should be considered in local honey bee biodiversity improvement and conservation initiatives.

Southern limit of Africanized honey bees in Argentina inferred by mtDNA and wing geometric morphometric analysis

African honey bee subspecies Apis mellifera scutellata began to spread in the American continent from southern Brazil in 1956. The process of Africanization involved both maternal and paternal bidirectional gene flow between European and Africanized honey bees. In Argentina, Africanized honey bees dominate in the northern semitropical regions and a hybrid area is defined between (ca. 32°–34°latitude). Although previous analysis has been carried out in Buenos Aires province, no analysis has been made south of this latitude. We used mitochondrial DNA (mtDNA) assays and wing geometric morphometrics to determine the prevalence of Africanized honey bees in managed populations. African mitotype origin and subspecies identity, were determined at three regions from Argentina. In our study, we analyzed 480 samples by wing morphometry and 157 by cytochrome-b assays, collected during 2013–2016. Our results show that North of 35°N latitude, honey bees with African mitotype were quite common (88.64%) finding high similarity with A. m. scutellata. South of that latitude, in temperate regions, we found African mitotype in only 18 of 133 colonies analyzed and a mixture of both European (A. m. ligustica, A. m. cárnica, A. m. mellifera) and African subspecies, most likely derived from North African honey bee (A. m. intermissa). Our results confirmed the existence of Africanized honey bee populations with a gradual cline from north to south, as a result from recent A. m. scutellata-derived bee expansion. Beyond the transition area between the 30°–35°S parallels bees carrying the European mitotype were fairly common.

Hydroxylation patterns associated with pheromone synthesis and composition in two honey bee subspecies Apis mellifera scutellata and A. m. capensis laying workers

Colony losses due to social parasitism in the form of reproductive workers of the Apis mellifera capensis clones results from the production of queen-like pheromonal signals coupled with ovarian activation in these socially parasitic honey bees. While the behavioral attributes of these social parasites have been described, their genetic attributes require more detailed exploration. Here, we investigate the production of mandibular gland pheromones in queenless workers of two sub-species of African honey bees; A. m. scutellata (low reproductive potential) and A. m. capensis clones (high reproductive potential). We used standard techniques in gas chromatography to assess the amounts of various pheromone components present, and qPCR to assess the expression of cytochrome P450 genes cyp6bd1 and cyp6as8, thought to be involved in the caste-dependent hydroxylation of acylated stearic acid in queens and workers, respectively. We found that, for both subspecies, the quality and quantity of the individual pheromone components vary with age, and that from the onset, A. m. capensis parasites make use of gene pathways typically upregulated in queens in achieving reproductive dominance. Due to the high production of 9-hydroxy-decenoic acid (9-HDA) the precursor to the queen substance 9-oxo-decenoic acid (9-ODA) in newly emerged capensis clones, we argue that clones are primed for parasitism upon emergence and develop into fully fledged parasites depending on the colony's social environment.

Comparative analysis of mitochondrial genomes of the honey bee subspecies A. m. caucasica and A. m. carpathica and refinement of their evolutionary lineages

The complete mitochondrial genome sequences of the honey bee subspecies Apis mellifera caucasica and Apis mellifera carpathica were analyzed for the first time. The length of the mitochondrial DNA (mtDNA) sequences of A. m. caucasica and A. m. carpathica are 16,341 and 16,336 bps, respectively. Both sequences contain 13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes, and 1 AT-rich region. The overall composition of the nucleotides in the mtDNA of A. m. caucasica/A. m. carpathica is as follows: A (43.2/43.3%), C (9.5/9.6%), G (5.6/5.5%), and T (41.6/41.6%). Most of the mtDNA genes of both subspecies (ND2, COX1, COX2, ATP8, ATP6, COX3, ND3, ND6, CYTB, and 14 tRNA genes) are located on the heavy strand, and less (ND1, ND4, ND4L, ND5, SrRNA, LrRNA, and 8 tRNA genes) are located on the light strand. Phylogenetic analysis based on the complete mtDNA showed that both subspecies A. m. caucasica and A. m. carpathica are representatives of the C lineage. Thirty-five unique markers (ND5/XbaI and 34 SNPs) were found which enable the differentiation of the honey bee subspecies A. m. caucasica and A. m. carpathica. These genetic markers can contribute to purebred beekeeping and will help to prevent hybridization between these endangered honey bee subspecies in Europe.

Performance of two honey bee subspecies during harsh weather and Acacia gerrardii nectar-rich flow

Both climatic factors and bee forage characteristics affect the population size and productivity of honey bee colonies. To our knowledge, no scientific investigation has as yet considered the potential effect of nectar-rich bee forage exposed to drastic subtropical weather conditions on the performance of honey bee colonies. This study investigated the performance of the honey bee subspecies Apis mellifera jemenitica Ruttner (Yemeni) and Apis mellifera carnica Pollmann (Carniolan) in weather that was hot and dry and in an environment of nectar-rich flora. The brood production, food storage, bee population and honey yield of Yemeni (native) and Carniolan (imported) colonies on Talh trees (Acacia gerrardii Benth.), a nectar-rich, subtropical, and summer bee forage source in Central Arabia were evaluated. Owing to their structural and behavioral adaptations, the Yemeni bees constructed stronger (high population size) colonies than the Carniolan bees. Although both groups yielded similar amounts of Talh honey, the Yemeni bees consumed their stored honey rapidly if not timely harvested. A. m. jemenitica has a higher performance than A. m. carnica during extremely hot-dry conditions and A. gerrardii nectar-rich flow.

The complete mitochondrial genome of the Egyptian honey bee, Apis mellifera lamarckii (Insecta: Hymenoptera: Apidae)

The complete mitochondrial genome of the western honey bee subspecies Apis mellifera lamarckii was sequenced. This mitochondrial genome is 16,589 bp in length with 37 classical eukaryotic mitochondrial genes and an A + T-rich region. Gene directions and arrangements are similar to those of other Apis mitogenomes. Seven genes begin with ATT, four with ATG, and two with ATA (none with ATC) and all genes terminate with TAA. Four genes are encoded on the heavy strand and nine are encoded on light strand. All of the 22 tRNA genes, ranging from 66 to 80 bp, have a typical cloverleaf structure. A phylogenetic tree showed that A.m. lamarckii clusters with other A. mellifera subspecies, as expected.

The complete mitochondrial genome of Apis mellifera meda (Insecta: Hymenoptera: Apidae)

The complete mitochondrial genome of the western honey bee subspecies Apis mellifera meda was sequenced. This mitochondrial genome is 16,248 bp in length, with 37 classical eukaryotic mitochondrial genes and an A + T-rich region. Gene direction and arrangement are similar to those of other Apis mitogenomes. All genes initiate with ATT (six genes), ATG (four genes), ATA (two genes), and ATC (one gene) start codons and terminate with a TAA stop codon. Four genes are encoded on the heavy and nine on the light strands, respectively. All of the 22 tRNA genes, ranging from 66 to 78 bp, have a typical cloverleaf structure. The complete mitogenome of A.m. meda provides information on the biogeography and evolution of A. mellifera subspecies.

Fertility and reproductive rate of Varroa mite, Varroa destructor, in native and exotic honeybee, Apis mellifera L., colonies under Saudi Arabia conditions.

Varroa mite is the most destructive pest to bee colonies worldwide. In Saudi Arabia, preliminary data indicated high infestation levels in the exotic honeybee colonies; such as Apis mellifera carnica and Apis mellifera ligustica, compared to native honeybee subspecies Apis mellifera jemenitica, which may imply higher tolerance to Varroasis. In this study, fertility and reproductive rate of Varroa mite, Varroa destructor, in capped brood cells of the native honeybee subspecies were investigated and compared with an exotic honeybee subspecies, A. m. carnica. Mite fertility was almost alike (87.5% and 89.4%) in the native and craniolan colonies respectively. Similarly, results did not show significant differences in reproduction rate between both subspecies (F = 0.66, Pr > F = 0.42). Number of adult Varroa daughters per fertile mother mite was 2.0 and 2.1 for native and craniolan honeybee subspecies respectively. This may indicate that mechanisms of keeping low infestation rates in the native honeybee colonies are not associated with Varroa reproduction. Therefore, potential factors of keeping lower Varroa infestation rates in native honey bee subspecies should be further investigated.

New SNP markers of the honeybee vitellogenin gene (Vg) used for identification of subspecies Apis mellifera mellifera L.

Preservation of the gene pool of honeybee subspecies Apis mellifera mellifera is of vital importance for successful beekeeping development in the northern regions of Eurasia. An effective method of genotyping honeybee colonies used in modern science is the mapping of sites of single nucleotide polymorphism (SNP). The honeybee vitellogenin gene (Vg) encodes a protein that affects reproductive function, behavior, immunity, longevity, and social organization in the honeybee Apis mellifera and is therefore a topical research subject. The results of comparative analysis of honeybee Vg sequences show that there are 26 SNP sites that differentiate M and C evolutionary branches and can be used as markers in selective breeding, DNA-barcoding, and the creation of genetic passports for A. m. mellifera colonies.

Climate rather than geography separates two European honeybee subspecies

Both climatic and geographical factors play an important role for the biogeographical distribution of species. The Carpathian mountain ridge has been suggested as a natural geographical divide between the two honeybee subspecies Apis mellifera carnica and A. m. macedonica. We sampled one worker from one colony each at 138 traditional apiaries located across the Carpathians spanning from the Hungarian plains to the Danube delta. All samples were sequenced at the mitochondrial tRNA(Leu)-cox2 intergenic region and genotyped at twelve microsatellite loci. The Carpathians had only limited impact on the biogeography because both subspecies were abundant on either side of the mountain ridge. In contrast, subspecies differentiation strongly correlated with the various temperature zones in Romania. A. m. carnica is more abundant in regions with the mean average temperature below 9 °C, whereas A. m. macedonica honeybees are more frequent in regions with mean temperatures above 9 °C. This range selection may have impact on the future biogeography in the light of anticipated global climatic changes.

A colony defence difference between two honey bee subspecies (Apis mellifera cypria and Apis mellifera caucasica)

SummaryColony defence differences between two honey bee subspecies Apis mellifera cypria and A. m. caucasica are reported. A. m. cypria formed significantly (P < 0.001) more defensive balls of bees covering intruders than A. m. caucasica in response to a predatory wasp attack. Although there were differences in ball formation, the number of bees attacking the wasp did not differ in the balls that were formed (P > 0.10). In addition to ball formation, A. m. cypria was tested for differences in frequency of attacking, shaking, shimmering, line formation and lunging when confronted with a live tethered wasp, dead tethered wasp or just the tethering line. Only the dead wasp elicited differential response. It is suggested that these difference in anti-predator behaviour are related to the high predation risks of A. m. cyrpria. Caucasian bees and their hybrids do not face to such wasp predation due to the cool weather in the Caucasus region.

Human Factors Facilitating the Spread of a Parasitic Honey Bee in South Africa

Workers of the honey bee subspecies Apis mellifera capensis (Eschscholtz) produce female offspring by thelytokous parthenogenesis and can parasitize colonies of other subspecies. In 1990, translocation of 400 colonies of A. m. capensis into the distribution area of A. m. scutellata by a commercial beekeeper triggered a dramatic parasitic phenomenon. Parasitized colonies died within a few months of infestation, and this resulted in the loss of tens of thousands of colonies by commercial beekeepers in the A. m. scutellata range in South Africa. To deal with the problem and to identify methods that would limit the impact of the social parasite, we investigated the link between beekeeping management and severity of parasitic infestations in terms of colony mortality and productivity. We demonstrate that colonies from apiaries subjected to migrations are very susceptible to infestation and consequently show dramatic mortality. Their productivity is also inferior to sedentary colonies and those in isolated apiaries in terms of honey yield and brood quantity. Furthermore, by concentrating hives in small areas and often in the vicinity of other beekeepers, cross-infestations can easily occur. This can undermine previously parasite-free beekeeping businesses. As a result of our surveys, we propose beekeeping practices based on locally trapped bees, reduced migration, and better control of parasite spread, thus promoting the conservation of these pollinators. If followed by all the South African beekeepers, these measures should limit the spread of the parasite until it is eliminated within a few years, after which full migratory beekeeping practices could resume.

Human Factors Facilitating the Spread of a Parasitic Honey Bee in South Africa

Workers of the honey bee subspecies Apis mellifera capensis (Eschscholtz) produce female offspring by thelytokous parthenogenesis and can parasitize colonies of other subspecies. In 1990, translocation of 400 colonies of A. m. capensis into the distribution area of A. m. scutellata by a commercial beekeeper triggered a dramatic parasitic phenomenon. Parasitized colonies died within a few months of infestation, and this resulted in the loss of tens of thousands of colonies by commercial beekeepers in the A. m. scutellata range in South Africa. To deal with the problem and to identify methods that would limit the impact of the social parasite, we investigated the link between beekeeping management and severity of parasitic infestations in terms of colony mortality and productivity. We demonstrate that colonies from apiaries subjected to migrations are very susceptible to infestation and consequently show dramatic mortality. Their productivity is also inferior to sedentary colonies and those in isolated apiaries in terms of honey yield and brood quantity. Furthermore, by concentrating hives in small areas and often in the vicinity of other beekeepers, cross-infestations can easily occur. This can undermine previously parasite-free beekeeping businesses. As a result of our surveys, we propose beekeeping practices based on locally trapped bees, reduced migration, and better control of parasite spread, thus promoting the conservation of these pollinators. If followed by all the South African beekeepers, these measures should limit the spread of the parasite until it is eliminated within a few years, after which full migratory beekeeping practices could resume.

A single locus determines thelytokous parthenogenesis of laying honeybee workers (Apis mellifera capensis)

The evolution and maintenance of parthenogenetic species are a puzzling issue in evolutionary biology. Although the genetic mechanisms that act to restore diploidy are well studied, the underlying genes that cause the switch from sexual reproduction to parthenogenesis have not been analysed. There are several species that are polymorphic for sexual and parthenogenetic reproduction, which may have a genetic basis. We use the South African honeybee subspecies Apis mellifera capensis to analyse the genetic control of thelytoky (asexual production of female workers). Due to the caste system of honeybees, it is possible to establish classical backcrosses using sexually reproducing queens and drones of both arrhenotokous and thelytokous subspecies, and to score the frequency of parthenogenesis in the resulting workers. We found Mendelian segregation for thelytoky of egg-laying workers, which appears to be controlled by a single major gene (th). The segregation pattern indicates a recessive allele causing thelytoky. We found no evidence for maternal transmission of bacterial endosymbionts controlling parthenogenesis. Thelytokous parthenogenesis of honeybee workers appears to be a classical qualitative trait, because we did not observe mixed parthenogenesis (amphitoky), which might be expected in the case of multi-locus inheritance.

The African honey bee: factors contributing to a successful biological invasion.

The African honey bee subspecies Apis mellifera scutellata has colonized much of the Americas in less than 50 years and has largely replaced European bees throughout its range in the New World. The African bee therefore provides an excellent opportunity to examine the factors that influence invasion success. We provide a synthesis of recent research on the African bee, concentrating on its ability to displace European honey bees. Specifically, we consider (a) the genetic composition of the expanding population and the symmetry of gene flow between African and European bees, (b) the mechanisms that favor the preservation of the African genome, and (c) the possible range and impact of the African bee in the United States.

Bacterial diversity in worker adults of Apis mellifera capensis and Apis mellifera scutellata (Insecta: Hymenoptera) assessed using 16S rRNA sequences

High-fidelity PCR of 16S rRNA sequences was used to identify bacteria associated with worker adults of the honeybee subspecies Apis mellifera capensis and Apis mellifera scutellata. An expected ≈1.5-kb DNA band, representing almost the entire length of the 16S rRNA gene, was amplified from both subspecies and cloned. Ten unique sequences were obtained: one sequence each clustered with Bifidobacterium (Gram-positive eubacteria), Lactobacillus (Gram-positive eubacteria), and Gluconacetobacter (Gram-negative α-proteobacteria); two sequences each clustered with Simonsiella (β-proteobacteria) and Serratia (γ-proteobacteria); and three sequences each clustered with Bartonella (α-proteobacteria). Although the sequences relating to these six bacterial genera initially were obtained from either A. m. capensis or A. m. scutellata or both, newly designed honeybee-specific 16S rRNA primers subsequently amplified all sequences from all individual workers of both subspecies. Attempts to amplify these sequences from eggs have failed. However, the wsp primers designed to amplify Wolbachia DNA from arthropods, including these bees, consistently produced a 0.6-kb DNA band from individual eggs, indicating that amplifiable bacterial DNA was present. Hence, the 10 bacteria could have been acquired orally from workers or from other substrates. This screening of 16S rRNA sequences from A. m. capensis and A. m. scutellata found sequences related to Lactobacillus and Bifidobacterium which previously had been identified from other honeybee subspecies, as well as sequences related to Bartonella, Gluconacetobacter, Simonsiella/Neisseria, and Serratia, which have not been identified previously from honeybees.

Evolution of extreme polyandry: an estimate of mating frequency in two African honeybee subspecies, Apis mellifera monticola and A.m. scutellata

Mating frequencies in two related honeybee subspecies Apis mellifera monticola and A. m. scutellata were compared using a set of five microsatellite loci in order to discriminate among the major factors which have affected the evolution of extreme polyandry. We found that the queens of eight A.m. monticola colonies collected from an apiary in Malawi, mated 5-19 times producing an average relatedness among workers of 0.328 ± 0.049. The six A.m. scutellata colonies collected from an apiary in South Africa displayed a significantly larger degree of polyandry, i.e. queens mated 10-25 times and the genetic relatedness among nestmates was 0.283 ± 0.020. The difference in the degree of polyandry observed between the populations suggests that socially based selective pressures are not of primary importance in the evolution of extreme polyandry but that ecological selective pressures play a more significant role. However, exploring the relative contributions of these factors to the variation in levels of polyandry will require the use of colonies in which the level of polyandry is experimentally controlled.