Modelling biocontrol of

The two haplotypes of Varroa destructor that have been identified as parasites of the Western honeybee (Apis mellifera L.) show disparate levels of virulence towards honeybee colonies. The Korea haplotype has been associated with severe colony mortality, whereas untreated colonies of European A. mellifera have survived long-term infestation by the Japan haplotype. The possible existence of a benign haplotype of V. destructor raises the prospect that it be used to “inoculate” colonies to provide biocontrol of the virulent haplotype. The feasibility of such a strategy was investigated using a mathematical model. Competition for resources during reproduction is known to reduce varroa mites’ reproduction rates as their infestation levels increase. Results from modelling suggested this density-dependent effect is sufficient for an established benign population to prevent the virulent population reaching destructive levels if a colony is subject to sporadic influxes of virulent mites. A colony faced with a continuous influx of mites could be protected if the proportion of virulent mites in the influx were below a threshold level (dependent on length of breeding season and intensity of influx). This condition might be achieved by “inoculating” neighbouring apiaries and controlling feral colonies in the vicinity. Decreased brood cell invasion rate by the benign haplotype decreased the threshold level. Any reproductive isolation between the benign and virulent haplotypes would cause further reproductive suppression, driving sporadic influxes of the virulent haplotype to extinction and conferring greater tolerance to a colony faced with a virulent influx. Increased colony resistance to varroa in the model was synergistic with the inoculation of colonies in the absence of reproductive isolation, but potentially antagonistic in its presence—although not to an extent that would preclude their joint use.     

Inference on microsatellite mutation processes in the invasive mite, Varroa destructor, using reversible jump Markov chain Monte Carlo

Varroa destructor is a parasitic mite of the Eastern honeybee Apis cerana. Fifty years ago, two distinct evolutionary lineages (Korean and Japanese) invaded the Western honeybee Apis mellifera. This haplo-diploid parasite species reproduces mainly through brother-sister matings, a system which largely favors the fixation of new mutations. In a worldwide sample of 225 individuals from 21 locations collected on Western honeybees and analyzed at 19 microsatellite loci, a series of de novo mutations was observed. Using historical data concerning the invasion, this original biological system has been exploited to compare three mutation models with allele size constraints for microsatellite markers: stepwise (SMM) and generalized (GSM) mutation models, and a model with mutation rate increasing exponentially with microsatellite length (ESM). Posterior probabilities of the three models have been estimated for each locus individually using reversible jump Markov Chain Monte Carlo. The relative support of each model varies widely among loci, but the GSM is the only model that always receives at least 9% support, whatever the locus. The analysis also provides robust estimates of mutation parameters for each locus and of the divergence time of the two invasive lineages (67,000 generations with a 90% credibility interval of 35,000-174,000). With an average of 10 generations per year, this divergence time fits with the last post-glacial Korea-Japan land separation.     

Phylogeographic Analysis of the Firefly, Luciola lateralis, in Japan and Korea Based on Mitochondrial Cytochrome Oxidase II Gene Sequences (Coleoptera: Lampyridae)

Luciola lateralis is widely distributed throughout the Korean Peninsula, northeast China, Sakhalin, and Japan. Two ecological types are recognized in Japan based on flash and hatching time characteristics. The mitochondrial cytochrome oxidase II gene was surveyed by restriction fragment length polymorphism analysis for Japan (46 populations) and Korea (two populations). Eleven haplotypes were detected. Gene trees revealed that haplotypes between Japan and Korea are much more differentiated in nucleotide sequences (8.1%) than those within Japan (0.3-1.4%) and Korea (0.7%). Haplotypes between Honshu and Hokkaido are not separated as clades, and the two ecological types cannot be segregated from each other phylogenetically. We suggest that the Japanese populations of this species may have dispersed within one million years ago and that ecological differences may be the result of physiological adaptation to cold climates.     

Prevalence of African DNA RELP alleles in neotropical African honeybees

A few queens of the honeybee, Apis mellifera scutellata, were imported from Africa and released in Brazil in 1957. Progeny of these bees have now largely colonized the American tropics. Their imminent arrival in the United States poses a serious threat to the beekeeping industry and to agriculture dependent on honeybee pollination. African and European bees are morphologically very similar. DNA restriction fragment length polymorphisms are proving successful in distinguishing between the two. Several DNA markers specific to European honeybees have been described previously. Reported here are three cloned honeybee DNA probes that reveal polymorphisms that appear to be either African or European specific. Of fourteen alleles or haplotypes identified, five were present only in African and neotropical (Venezuelan and Mexican) African bees but absent in European-derived bees, two were present only in European-derived bees but absent in samples from South Africa. Another allele showed apparent frequency differences among populations. Such markers are useful in studying the genetics of neotropical African bee populations. Venezuelan and Mexican honeybee colonies show a preponderance of the African alleles with low levels of the European alleles. These observations of nuclear DNA, revealing limited paternal European introgression, together with previous mitochondrial DNA findings showing negligible European maternal gene flow into feral African populations, indicate that neotropical African bees are primarily African.     

蜜蜂幼虫血淋巴游离氨基酸和微量元素含量的差异对其抗螨特性的影响

重新界定的外寄生螨类---狄斯瓦螨Varroa destructor(Anderson and Trueman),严重危害全世界的西方蜜蜂Apis mellifera。但是对其原始寄主东方蜜蜂Apis cerana不构成可见的危害。在西方蜜蜂群中,狄斯瓦螨在雄蜂房和工蜂房都能进行繁殖。在其亚洲的原始寄主东方蜜蜂群中,它们可以寄生于雄蜂和工蜂,但在工蜂房中不育。蜜蜂的血淋巴是狄斯瓦螨生存和繁殖需要摄取的惟一食物来源,推测血淋巴中的某种物质含量会影响狄斯瓦螨的繁殖。对中华蜜蜂Apis ceranaFabricius和意大利蜜蜂ApismelliferaL.工蜂和雄蜂封盖幼虫血淋巴中游离氨基酸和与营养有关的微量元素含量进行了比较,发现其存在明显差异,并推测这些差异与东方蜜蜂抗螨能力强有关。     

Mitochondrial DNA variability in the Canary Islands honeybees (Apis mellifera L.)

The mitochondrial DNA (mtDNA) of individuals from 79 colonies of Apis mellifera from five Canary Islands was studied using the Dra I test based on the restriction of PCR products of the tRNAleu–COII intergenic region. Five haplotypes of the African (A) lineage and one of the west European (C) lineage were found. The haplotypes A14 and A15 are described for the first time. These haplotypes have a new P sequence named P₁. The wide distribution and high frequency of haplotype A15 suggest that it is characteristic of the Canarian Archipelago. Sources of haplotype variability of honeybee mtDNA in the Canary Islands (waves of colonization from Africa, queen importations, habitat diversification) are discussed.     

Population differentiation in the Pacific white-sided dolphin Lagenorhynchus obliquidens inferred from mitochondrial DNA and microsatellite analyses

We investigated genetic diversity and differentiation of the Pacific white-sided dolphin (Lagenorhynchus obliquidens) in Japanese coastal waters and offshore North Pacific by analyzing mitochondrial DNA and nuclear microsatellite variation. A total of 519 bp of the mitochondrial control region was sequenced and five microsatellite locus were genotyped for 59 individuals. A high level of haplotypic diversity (h=96.1%), moderate level of nucleotide diversity (pi=1.65%) and average expected heterozygosity (HE=0.66-0.76) were within an extent of those reported for other odontocetes. Consistent genetic difference between the samples from Japanese coastal Pacific-Sea of Japan and offshore North Pacific was indicated by analyses of molecular variance (AMOVAs) based on mtDNA and microsatellite variations, comparison of genetic variabilities, and geographical distributions of mtDNA haplotypes and microsatellite alleles. This result suggests that Pacific white-sided dolphins in each of the above two areas belong to different populations between which gene flow has been severely restricted. The low genetic diversity and mtDNA genealogy of the population in Japanese coastal waters suggest that it originated from a small population that colonized the Sea of Japan or that experienced population reduction when this Sea was isolated from the North Pacific during a glacial period in the Late Pleistocene.     

Microsatellite analysis of non-migratory colonies of Apis mellifera iberica from south-eastern Spain

Forty‐five unmanaged honeybee colonies from the south‐east of the Iberian Peninsula (Apis mellifera iberica) were selected for analysing their genetic structure using eight microsatellite loci. These colonies were not subjected to management for queen replacement, rearing or migratory movements and previous studies showed that they had mitochondrial DNA (mtDNA) of African origin. Six of the microsatellite loci show intermediate levels of polymorphism with a total number of alleles detected per locus ranging from 4 to 10. Microsatellite data relate these Iberian populations to the African A. m. intermissa, although the presence of some alleles and the observed heterozygosity are characteristic of the European A. m. mellifera, thus corroborating the postulated hybrid origin of A. m. iberica. The results suggest that no recent introgression from Africa has happened and that the populations of A. m. iberica are differentiated in many demes.     

Genetic Variation of the Siberian Sturgeon (<Emphasis Type="Italic">Acipenser baerii</Emphasis> Brandt, 1869) in Aquaculture

Genetic variation of aquaculture broodstocks of the Siberian sturgeon of different origin from 13 farms across the Russian Federation was assessed at five tetraploid microsatellite loci and the mitochondrial DNA control region. At present, in aquaculture stocks of Siberian sturgeon originating from the Lena and Ob rivers, a sharp decline of haplotype diversity is observed. The most part of aquaculture individuals carry two major haplotypes characteristic of the European part of Russia (the Lena aquaculture) and two haplotypes characteristic of the western part of Siberia (the Ob aquaculture). According to the results of the microsatellite analysis, in sturgeon aquaculture stock originating from the Lena River, two genetic clusters can be distinguished. One of these clusters is represented by the stocks composed of inbred individuals and, because of this, is characterized by depleted allelic variation and the loss of rare alleles.     

Genetic differentiation among populations and color variants of sea cucumbers (Stichopus japonicus) from Korea and China

The Far Eastern sea cucumber, Stichopus japonicus, is a favored food in Eastern Asia, including Korea, Japan, and China. Aquaculture production of this species has increased because of recent declines in natural stocks and government-operated stock release programs are ongoing. Therefore, the analyses of genetic structure in wild and hatchery populations are necessary to maintain the genetic diversity of this valuable marine resource. In addition, given that sea cucumber color affects market price, with the rare, possibly reproductively isolated, red type being the most valuable, an understanding of the genetic structure and diversity in color variation of green and red types is necessary. We analyzed the genetic structure of wild and hatchery-produced green type S. japonicus from Korea and China, and wild red type from Korea using 9 microsatellite makers. The number of alleles per locus ranged from 11 to 29 across all populations. The mean allele numbers of the green types from Korea (10.6) and China (10.1) were similar, but differed slightly from that of the red type (9.1). Pairwise multilocus F(ST) and genetic distance estimations showed no significant differences between the green types from Korea and China, whereas the differences between the green and red types were significant. This was clearly illustrated by a UPGMA dendrogram, in which the two close subclusters of green types were completely separated from the red type. In addition, the allele frequencies of the green and red types were significantly different. Assignment tests correctly assigned 100% (quality index 99.97%) of individuals to their original color types and demonstrated the feasibility of microsatellite analysis for discrimination between color types.     

Y chromosomal DNA variation and the peopling of Japan.

Four loci mapping to the nonrecombining portion of the Y chromosome were genotyped in Japanese populations from Okinawa, the southernmost island of Japan; Shizuoka and Aomori on the main island of Honshu; and a small sample of Taiwanese. The Y Alu polymorphic (YAP) element is present in 42% of the Japanese and absent in the Taiwanese, confirming the irregular distribution of this polymorphism in Asia. Data from the four loci were used to determine genetic distances among populations, construct Y chromosome haplotypes, and estimate the degree of genetic diversity in each population and on different Y chromosome haplotypes. Evolutionary analysis of Y haplotypes suggests that polymorphisms at the YAP (DYS287) and DXYS5Y loci originated a single time, whereas restriction patterns at the DYS1 locus and microsatellite alleles at the DYS19 locus arose more than once. Genetic distance analysis indicated that the Okinawans are differentiated from Japanese living on Honshu. The data support the hypotheses that modern Japanese populations have resulted from distinctive genetic contributions involving the ancient Jomon people and Yayoi immigrants from Korea or mainland China, with Okinawans experiencing the least amount of admixture with the Yayoi. It is suggested that YAP+ chromosomes migrated to Japan with the Jomon people > 10,000 years ago and that a large infusion of YAP- chromosomes entered Japan with the Yayoi migration starting 2,300 years ago. Different degrees of genetic diversity carried by these two ancient chromosomal lineages may be explained by the different life-styles (hunter-gatherer versus agriculturalist). of the migrant groups, the size of the founding populations, and the antiquities of the founding events.     

Varying degrees of Apis mellifera ligustica introgression in protected populations of the black honeybee, Apis mellifera mellifera, in northwest Europe

The natural distribution of honeybee subspecies in Europe has been significantly affected by human activities during the last century. Non-native subspecies of honeybees have been introduced and propagated, so that native black honeybee (Apis mellifera mellifera) populations lost their identity by gene-flow or went extinct. After previous studies investigated the remaining gene-pools of native honeybees in France and Spain, we here assess the genetic composition of eight northwest European populations of the black honeybee, using both mitochondrial (restriction fragment length polymorphisms of the intergenic transfer RNAleu-COII region) and nuclear (11 microsatellite loci) markers. Both data sets show that A. m. mellifera populations still exist in Norway, Sweden, Denmark, England, Scotland and Ireland, but that they are threatened by gene flow from commercial honeybees. Both Bayesian admixture analysis of the microsatellite data and DraI-RFLP (restriction fragment length polymorphism) analysis of the intergenic region indicated that gene-flow had hardly occurred in some populations, whereas almost 10% introgression was observed in other populations. The most introgressed population was found on the Danish Island of Laeso, which is the last remaining native Danish population of A. m. mellifera and the only one of the eight investigated populations that is protected by law. We discuss how individual admixture analysis can be used to monitor the restoration of honeybee populations that suffer from unwanted hybridization with non-native subspecies.     

Geographical overlap of two mitochondrial genomes in Spanish honeybees (Apis mellifera iberica)

Restriction enzyme cleavage maps of mitochondrial DNA from the Spanish honeybee, Apis mellifera iberica (Hymenoptera: Apidae), were compared with those from the European subspecies A. m. mellifera, A. m. ligustica, and A. m. carnica, and the African subspecies A. m. intermissa and A. m. scutellata. The mitochondrial DNA (mtDNA) of the two African subspecies can be distinguished by restriction fragment polymorphisms revealed by Hinf I digests. Two distinct mtDNA types were found among Spanish honeybees: a west European mellifera-like type, which predominates in the north of Spain, and an African intermissa-like type, which predominates in the south. Spain appears to be a region of contact and hybridization between the two subspecies A. m. intermissa and A. m. mellifera, which respectively represent African and west European honeybee lineages. This natural boundary between European and African honeybee populations in the Old World may provide a model for predicting the eventual outcome of the colonization of North America by introduced African honeybees.     

Diversity of Apis mellifera Subspecies from Turkey Revealed by Sequence Analysis of Mitochondrial 16s rDNA Region

Mitochondrial DNA sequence variation can be used to infer honeybee evolutionary relationships. In this study, DNA sequence diversity of the mitochondrial 16s rDNA region was investigated in 112 honeybees from 15 populations in Turkey, which is mainly populated with Apis mellifera anatoliaca, A. m. caucasica, and A. m. meda. The study revealed 11 haplotypes for this segment, with 13 variable sites and nine parsimony informative sites. The haplotypes were not discriminated according to their geographical locations in a neighbor-joining dendrogram based on 16s rDNA sequences available in Genbank, but all the haplotypes obtained in this study are clustered with published haplotypes such as A. mellifera TAS (AF214666) and A. m. ligustica (EF116868) and with some unpublished Genbank records (HQ318928, HQ318934, and HQ318938). This study expands the knowledge of the mitochondrial 16s rDNA region, and it presents the first comprehensive sequence analysis of this region in Turkish honeybees.     

蜜蜂（Apis）苹果酸脱氢酶同工酶的研究进展

苹果酸脱氢酶（MDH）是糖代谢中重要的酶。在西方蜜蜂（Apis mellifera L.）中,MDH分为3个区带MDHⅠ、MDHⅡ和MDH Ⅲ。不同级型和不同发育阶段,MDHⅠ和MDH Ⅲ变化不大;MDHⅡ呈现多态现象,由a、b、c3个等位基因编码。东方蜜蜂（A.cerana F.）的MDH由S、F两个等位基因编码,也有报道它是单态性的。MDH在西方蜜蜂研究中应用较多,主要有处女王交配次数;蜂群中的劳动分工;蜜蜂种群遗传组成分析等。MDH和分子生物学的结合研究势必将推动蜜蜂研究的深入和发展。 Research Progress in Malate Dehydrogenase(MDH) of Honeybees LIU Yan-he1,ZHANG Chuan-xi1,XU Bao-hua2,3,CHEN Sheng-lu1 1.Institute of Applied Entomology,Zhejiang University,Hangzhou 310029,China; 2.College of Animal Science,Zhejiang University,Hangzhou 310029,China; 3.College of Animal Sciences,Shandong Agricaltural University,Taian 271018,China Abstract:Malate dehydrogenase(MDH) is an important enzyme in glycometabolism.MDH of Apis mellifera showed three enzyme active zones,MDHⅠ,MDHⅡand MDHⅢ.MDHⅠand MDHⅢ maintained relative stability in different castes and developmental phases,but MDHⅡwas polymorphic,and controlled by three alleles,a,b and c.MDH of Apis cerana was coded by S and F alleles,but some authors reported it is monomorphic.MDH was applied to the studies of A.mellifera,which included several aspects as follows:the number of queen matings,labor division in honeybee societies,the analysis of genetic constitution in honeybee populations and so on.The combination of both MDH and molecular biology will certainly promote honeybee studies. Key words：honeybees;malate dehydrogenase(MDH)     

Phylogeography and population structure of the saker falcon (Falco cherrug) and the influence of hybridization: mitochondrial and microsatellite data

Microsatellite as well as sequence analysis of the mitochondrial control region were applied to infer phylogeography and population genetic structure of the saker falcon (Falco cherrug). Furthermore, we compared the patterns of mitochondrial haplotypes with the variation of microsatellite alleles among the species of the hierofalcon complex (F. cherrug, Falco rusticolus, Falco biarmicus, Falco jugger) to test hypotheses on population history. Historical samples from museum specimens of F. cherrug were analysed together with samples from contemporary populations to investigate possible influences of hybrid falcons escaped from falconry on the genetic composition. In the mitochondrial DNA analysis, none of the four species represents a monophyletic group. Moreover, there are no clearly defined groups of haplotypes corresponding to taxonomic entities. In the microsatellite analysis most of the variation is shared between species and no clear differentiation by private alleles is found. Yet, with a Bayesian clustering method based on allele frequencies, a differentiation of F. cherrug, F. rusticolus and two geographic groups of F. biarmicus was detected. Results from both nuclear and mitochondrial markers are compatible with the previously postulated 'Out of Africa' hypothesis assuming an African origin of the hierofalcons. From an ancestral African population, F. cherrug, F. rusticolus and F. jugger split off in separate waves of immigration into Eurasia and South Asia. A combination of evolutionary processes, including incomplete lineage sorting as well as hybridization, may be responsible for the currently observed genetic patterns in hierofalcons.     

Genetic diversity and population structure of the Black-faced Spoonbill (Platalea minor) among its breeding sites in South Korea: Implication for conservation

The endangered Black-faced Spoonbill Platalea minor has experienced drastic reductions in population size, geographic distribution, and habitat availability throughout East Asia. In the present study, we examined population genetic structure and genetic diversity of Black-faced Spoonbills inhabiting five sites off the west coast of South Korea encompassing a few of its major breeding sites. Ten microsatellite loci and the mitochondrial sequence were used to assess patterns of genetic variation based on 63 individuals. Three ND2 haplotypes were found among 61 individuals; the remaining two were identified as Eurasian Spoonbills, revealing an unexpected hybridization between these two species having different ecological niches in South Korea—the Eurasian Spoonbill overwinters in inland areas, whereas the Black-faced Spoonbill inhabits coastal areas during the summer. Analyses of microsatellite variation revealed no discrete population structure among the five breeding sites but very weak genetic differentiation among geographically distant regions. Assignment tests identified several possible migrants among sites. Our findings suggested that Black-faced Spoonbills from the five breeding sites could be managed as a single population and highlighted the importance of conserving the populations from Maedo, Suhaam, and Namdong reservoir, which are geographically close and have retained high levels of genetic diversity and large populations.     

Mitochondrial microsatellite variability in common wheat and its ancestral species

On the basis of the entire mitochondrial DNA sequence of common wheat, Triticum aestivum, 21 mitochondrial microsatellite loci having more than ten mononucleotide repeats were identified. The mitochondrial microsatellite variability at all loci was examined with 43 accessions from 11 Triticum and Aegilops species involved in wheat polyploidy evolution. Polymorphic banding patterns were obtained at 15 out of 21 mitochondrial microsatellite loci. The number of alleles per polymorphic microsatellite ranged from 2 to 5 with an average of 3.07, and the diversity values (H) ranged from 0.09 to 0.50 with an average of 0.29. These values are almost two third of wheat chloroplast microsatellite values, indicating that variability of mitochondrial microsatellite is much less than that of chloroplast microsatellite. Based on the allele variation at all loci, a total of seven mitochondrial haplotypes were identified among common wheat and its ancestral species. Three diploid species showed their own specific haplotypes and timopheevi group (11 accessions) had three types, whereas 29 accessions of emmer and common wheat groups shared the same haplotype. These results indicate that a single mitochondrial haplotype determined by microsatellite analysis has conservatively been maintained in the evolutionary lineage from wild tetraploid to cultivated hexaploid species.     

The population genetics of a biological control introduction: mitochondrial DNA and microsatellie variation in native and introduced populations of Aphidus ervi, a parisitoid wasp

Introductions of biological control agents may cause bottlenecks in population size despite efforts to avoid them. We examined the population genetics of Aphidius ervi (Hymenoptera: Braconidae), a parasitoid that was introduced to North America from Western Europe in 1959 to control pea aphids. To explore the phylogeographical relationships of A. ervi we sequenced 1249 bp of mitochondrial DNA (mtDNA) from 27 individuals from the native range and 51 individuals from the introduced range. Most individuals from Western Europe, the Middle East and North America shared one of two common haplotypes, consistent with the known history of the introduction. However, some A. ervi from the Pacific Northwest have a haplotype that is most similar to haplotypes found in Japan, raising the possibility of a second accidental introduction. To examine population structure and assess whether a bottleneck occurred upon introduction to North America, we assayed variation at 5 microsatellite loci in 62 individuals from 2 native populations and 230 individuals from 6 introduced populations. Introduced samples had fewer rare alleles than native samples (F1,34 = 13.5, P = 0.0008), but heterozygosity did not differ significantly. These results suggest that a mild bottleneck occurred in spite of the introduction of over 1000 individuals. Using a hierarchical Bayesian approach, the founding population size was estimated to be 245 individuals. amova showed significant genetic differentiation between the European and North American samples, and a Bayesian assignment approach clustered individuals into four groups, with most European individuals in one group and most North American individuals in the other three. These results highlight that genetic changes are associated with founder events in rapidly growing natural populations, even when the founding population size is relatively large.     

Genetic structure and distinctness of Apis mellifera L. populations from the Canary Islands

The genetic structure of Apis mellifera populations from the Canary Islands has been assessed by mitochondrial (restriction fragment length polymorphisms of the intergenic transfer RNAleu-COII region) and nuclear (microsatellites) studies. These populations show a low level of genetic variation in terms of average number of alleles and degree of heterozygosity. Significant differences in the distribution of alleles were found in both data sets, confirming the genetic differentiation among some of the islands but not within them. Two mitochondrial haplotypes characteristic of the Canary Islands are found at high frequencies, although populations are introgressed by imported honeybees of eastern European C lineage. This introgression is rather high on Tenerife and El Hierro and low on Gran Canaria and La Gomera, whereas on La Palma it has not been recorded. The finding of microsatellite alleles characteristic of the eastern European lineage corroborates the genetic introgression. Phylogenetic analyses indicate that the Canarian honeybees are differentiated from other lineages and provide genetic evidence of their African origin.