Genetic diversity of <Emphasis Type="Italic">Salanx ariakensis</Emphasis> (Salangidae) from Korea and Japan inferred from AFLP

The genetic diversity and population structures within and between Korean and Japanese populations of Salanx ariakensis were investigated using AFLP (amplified fragment length polymorphism). Using seven primer pair sets, 411 fragments were amplified from 31 specimens of S. ariakensis, 393 fragments (96%) being polymorphic. The expected heterozygosities were 0.211 and 0.245 for the Japanese and Korean populations, respectively, levels similar to those of other freshwater and diadromous fishes, but lower than those of marine fishes. The difference in genetic diversity between the two populations may result from their different habitat sizes. Principal coordinate analysis using 393 polymorphic fragments resulted in specimens from each population being plotted separated, suggesting an absence (or little if present) gene flow between them since Tsushima Strait has been open. Therefore, each population of S. ariakensis is relevant from the conservation perspective and should at least be treated as a “management unit” for conservation purposes.     

Mitochondrial DNA analysis of the introduced fall webworm, showing its shift in life cycle in Japan

The fall webworm, Hyphantria cunea (Drury) (Lepidoptera: Arctiidae), was introduced from North America into Japan in 1945. For the first three decades after its introduction, its life cycle was bivoltine. Thereafter, its life cycle shifted to trivoltine in south‐western areas of Japan. Two hypotheses have been proposed for the process that led to the shift in voltinism: one based on a single and the other on multiple independent colonizations. To test these hypotheses, mitochondrial (mt)DNA sequences were analyzed in the black‐headed type of 14 Japanese, one Korean and two North American populations of H. cunea. In addition, the same regions of mtDNA were compared with the red‐headed type of two North American populations. In the black‐headed type, mtDNA sequences were the same in all Japanese populations and in the Korean population, but sequences of the North American populations differed from each other and from those of the other populations. These results suggest that the process of the shift in voltinism occurred originally in Japan, and that the Japanese and the Korean population of H. cunea originated from a relatively small area in North America.     

Phylogenetic relationships of silver crusian carp Carassius auratus gibelio, C. auratus cuvieri, crucian carp Carassius carassius, and common carp Cyprinus carpio as inferred from mitochondrial DNA variation

PCR-RFLP analysis of the ND3/ND4L/ND4 and 12S/16S rRNA regions and nucleotide sequence variation of the cytochrome b gene were used to study the mtDNA divergence in species of the family Cyprinidae, to examine the phylogenetic relationships of the species, and to identify their taxonomic status. The results indicated that an ancestral form diverged into silver crucian carp and crucian carp after its separation from the common carp lineage. The divergence of continental Carassius auratus gibelio and Japanese C. auratus cuvieri occurred more recently. Two well distinguishable mtDNA phylogroups, suggesting divergent evolution, were observed in continental C. auratus gibelio populations. The divergence was possibly related to the formation of two silver crucian carp groups with different types of reproduction, triploid gynogenetic and diploid gonochoric. At the same time, the results supported the high probability of current genetic exchange between the forms. In view of these findings and high morphological similarity of the two forms, they were not considered to be separate species.     

Phylogeography and conservation genetics of the hellbender salamander (Cryptobranchus alleganiensis)

We investigated hellbender phylogeography through phylogenetic analyses of individuals sampled from 16 locations throughout their range in the eastern United States. Analyses were conducted on concatenated cytochrome-oxidase I (COI), cytochrome-b (Cytb) and NADH dehydrogenase subunit 4 (ND4) mtDNA sequence, totaling 2160 nucleotides. Hellbender haplotypes differed by 0.1 to 5.8% maximum likelihood (ML) corrected sequence divergence. Phylogenetic analyses reveal that hellbenders are separated into 8 reciprocally monophyletic populations or clades differentiated by a minimum of 0.7 to 5.4% sequence divergence, each of which constitutes a separate Management Unit (MU). High among population divergence and reciprocal monophyly suggest that female-mediated gene flow is severely restricted or non-existent among each MU. Hellbenders are currently divided into two subspecies, Cryptobranchus alleganiensis alleganiensis and C. a. bishopi based on morphological characters. The phylogenetic analyses presented here strongly indicate that these subspecies are paraphyletic. Management priorities for the hellbender should be reconsidered in light of these new molecular data. Results from Bayesian rooting indicate the root of the hellbender mtDNA tree lies on the branch leading to hellbender haplotypes from the Current, Eleven Point and New Rivers. The rooted tree suggests that a common ancestor in the southern Ozarks and/or southern Appalachians gave rise to northern hellbender populations, consistent with a Pleistocene refuge hypothesis.     

Molecular variation of Spiranthes sinensis (Orchidaceae) in Japan, with special reference to systematic treatment of seasonally differentiated groups and a dwarf form, f. gracilis, from Yakushima Island

Molecular variations of Spiranthes sinensis Ames var. australis (R.Br.) H. Hara et Kitam. ex Kitam. in Japan were examined to evaluate the validity of the seasonally differentiated groups and a dwarf form of the species, which is endemic to Yakushima Island, Japan. Sequence differences in the plastid trnL-F locus clearly distinguished Japanese S. sinensis var. australis from S. sinensis var. sinensis collected from Ryukyu. In contrast, the trnL-F sequence of S. sinensis var. australis from Sabah, Malaysia, clearly differed from that of Japanese S. sinensis var. australis, suggesting genetic heterogeneity of Spiranthes sinensis var. australis in Asia. Moreover, a molecular analysis based on the sequences of nuclear ITS1 regions indicated that there are two major groups of S. sinensis var. australis in Japan, with a geographic distribution boundary on Kyushu Island. However, the trnL-F and ITS1 sequences did not support the genetic differentiation of the seasonally differentiated groups or the dwarf form from the other Japanese individuals. Based on these molecular data, the systematic treatment of physiological and morphological variations in the Japanese population of S. sinensis. var. australis is discussed.     

Evidence of a secondary interspecific mitochondrial DNA introgression in the pond loach Misgurnus dabryanus (Teleostei: Cobitidae) population introduced in Japan

The pond loach Misgurnus dabryanus is a freshwater fish with a distribution range spanning the eastern part of the Asian continent, the Korean Peninsula, and Taiwan. The pond loach was transplanted to the Japanese archipelago through the co-inclusion with dojo loach (Misgurnus anguillicaudatus species complex) populations, which were imported live from China for food materials, and it is currently distributed widely across Japan. A previous mitochondrial DNA (mtDNA) analysis revealed that a pond loach population in Ehime Prefecture (Shikoku Island, Japan) included two highly diverged mtDNA groups (Groups I and II). To examine the origin of these two distinct forms of mtDNA within the Japanese pond loach population, we performed phylogenetic analyses using sequences based on the mtDNA of cytochrome oxidase b (cyt b) and the nuclear DNA recombination activating gene 1 (RAG-1). We also conducted a random amplified polymorphic DNA (RAPD) analysis to examine the establishment of reproductive isolation between sympatric pond loaches with two different mtDNA groups. Our mtDNA phylogenetic results indicated that the two diverged pond loach mtDNA sequences showed polyphyletic relationships among Misgurnus species and its related genus Cobitis. In contrast, there were no clear divergence in nuclear DNA among the pond loaches irrespective of their mtDNA groups, and they all formed monomorphic clades in the phylogenetic relationships among the species. The discrepancy between the mtDNA and nuclear DNA genes support that the existence of two diverged forms of DNA within the pond loach population could be attributed to past mtDNA introgressions from other species rather than convergent evolution. Previous mtDNA phylogenetic studies among Cobitidae revealed that the dojo loach also consisted of two genetically diverged polyphyletic clades: an original Misgurnus mtDNA and an introgressed mtDNA from Cobitis species. In our mtDNA result, the Group II haplotype of the pond loach was included in the mtDNA from the introgressed dojo loach. This suggested that the Group II haplotype was derived from introgressed dojo loach mtDNA. The close relationships between the introgressed dojo loach and the pond loach mtDNA indicated that this secondary introgression had recently occurred via hybridization in a recent artificial aquaculture or transportation process. Common RAG-1 alleles and RAPD bands were shared between the sympatric pond loaches with original and introgressed mtDNAs. This indicates that the introgressed mtDNA haplotype is included as one of the polymorphic genotypes within the pond loach populations, and does not represent existence of different cryptic species.     

The endangered Sonoran topminnow: Examination of species and ESUs using three mtDNA genes

There has been controversy over the species status of Sonoran topminnows and debate about the presence of ESUs in the Gila topminnow. From examination of sequence variation at 2626 base pairs over three mtDNA genes, we found a 29 (1.1%) nucleotide genetic difference between Gila and Yaqui topminnows. This provides strong support that these two taxa are separate species, Poeciliopsis occidentalis (Gila topminnow) and P. sonoriensis (Yaqui topminnow) and have been separated for approximately one million years. All the Gila topminnows within Arizona have the same sequence for the three mtDNA genes, that is, there is not reciprocal monophyly for mtDNA sequence data for the two previously designated ESUs. However, evidence of the unique habitat for Monkey Spring, its long-term isolation from other Gila topminnow habitats, and the presence of unique fish and invertebrate taxa in Monkey Spring support the designation of the Monkey Spring topminnows as an ESU. Finally, theoretical considerations using molecular data and estimates of heterozygosity and genetic distance for nuclear genes between populations of the Gila topminnow show that the lack of mtDNA variation is not inconsistent with the level and pattern of nuclear genetic variation observed.     

Patterns of nuclear and mitochondrial DNA variation in Iberian populations of <Emphasis Type="Italic">Emys orbicularis</Emphasis> (Emydidae): conservation implications

The European pond turtle (Emys orbicularis) is threatened and in decline in several regions of its natural range, due to habitat loss combined with population fragmentation. In this work, we have focused our efforts on studying the genetic diversity and structure of Iberian populations with a fine-scale sampling (254 turtles in 10 populations) and a representation from North Africa and Balearic island populations. Using both nuclear and mitochondrial markers (seven microsatellites, ∼1048 bp nDNA and ∼1500 bp mtDNA) we have carried out phylogenetic and demographic analyses. Our results show low values of genetic diversity at the mitochondrial level although our microsatellite dataset revealed relatively high levels of genetic variability with a latitudinal genetic trend decreasing from southern to northern populations. A moderate degree of genetic differentiation was estimated for Iberian populations (genetic distances, F _ST values and clusters in the Bayesian analysis). The results in this study combining mtDNA and nDNA, provide the most comprehensive population genetic data for E. orbicularis in the Iberian Peninsula. Our results suggest that Iberian populations within the Iberian–Moroccan lineage should be considered as a single subspecies with five management units, and emphasize the importance of habitat management rather than population reinforcement (i.e. captive breeding and reintroduction) in this long-lived species.     

Genetic Variation in Wild and Hatchery Stocks of Suminoe Oyster (Crassostrea ariakensis) Assessed by PCR-RFLP and Microsatellite Markers

Genetic variation in wild Asian populations and U.S. hatchery stocks of Crassostrea ariakensis was examined using polymerase chain reactions with restriction fragment length polymorphism (PCR-RFLP) analysis of both the mitochondrial COI gene and the nuclear internal transcribed spacer (ITS) 1 region and using 3 microsatellite markers. Hierarchical analysis of molecular variance and pairwise comparisons revealed significant differentiation (P < 0.05) between samples from the northern region, represented by collections from China and Japan, and 2 of 3 samples from southern China. PCR-RFLP patterns were identified that were diagnostic for the northern (N-type) and southern (S-type) groups. Microsatellite marker profiles were used to assign each oyster to one of the two northern or two southern populations. Results for more than 97% of the oysters were consistent with the PCR-RFLP patterns observed for each individual in that oysters with N-type patterns were assigned to one of the northern populations and those with S-type patterns to one of the southern populations. At one site of the Beihai (B) region in southern China a mix of individuals with either the N-type or S-type PCR-RFLP genotypes was found. No heterozygotes at the nuclear ITS-1 locus were found in the sample, possibly indicating reproductive isolation in sympatry. Microsatellite assignment test results of the B individuals were also consistent with identifications as either the N-type or S-type based on PCR-RFLP patterns. The parental population for one hatchery stock was this B sample, which initially was composed of almost equal numbers of northern and southern genetic types. After hatchery spawns, however, more than 97% of the progeny fell into the northern genetic group by PCR-RFLP and microsatellite assignment test analyses, indicating that the individuals with the southern genotype contributed little to the spawn, owing to gametic incompatibility, differential larval survival, or a difference in timing of sexual maturity. Overall, results suggested that oysters collected as C. ariakensis in this study, and likely in other studies as well, include two different sympatric species with some degree of reproductive isolation.     

Geographic variations in Pacific sand eels <Emphasis Type="Italic">Ammodytes personatus</Emphasis> (Ammodytidae) from Korea and Japan using multivariate morphometric analysis

Multivariate methods were used to compare meristic and morphometric characters of Ammodytes personatus from four populations in Korea (3) and Japan (1). ANCOVA showed the slopes of head length (Japan > East > South > West) and body depth (South > Japan > East > West) relative to total length to differ significantly among populations. Vertebrae and fin rays’ numbers differed significantly among populations, the former ranging between 64 and 67 (mode = 65, 66) in the East population, 62–67 (63, 64) in the West population and 62–64 (62, 63) in the South population in Korea. PCA and CDA, based on 14 morphometric characters, showed that scores plotted on axes 1-2 and 2-3 separated the three Korean populations but overlapped between the South and Japanese populations. These results suggest that the Korean A. personatus may comprise at least two populations. The text was submitted by the authors in English.     

Species limits and population differentiation in New Zealand snipes (Scolopacidae: <Emphasis Type="Italic">Coenocorypha</Emphasis>)

At least four species of New Zealand snipes (Coenocorypha) became extinct following the introduction of predatory mammals, and another two species suffered massive range reductions. To investigate species limits and population differentiation in six of the seven remaining offshore populations, we assayed variation in nine microsatellite loci and 1,980 base pairs of four mitochondrial DNA (mtDNA) genes. Genetic diversity in all populations except the largest one on Adams Island in the Auckland Islands was very low in both genomes. Alleles were fixed at many microsatellite loci and for single mtDNA haplotypes, particularly in the populations in the Chathams, Snares, Antipodes and Campbell Islands. Strong population structure has developed, and Chathams and Snares Islands populations are effectively genetically isolated from one another and from the more southern island populations. Based on reciprocal monophyly of lineages and their morphological distinctiveness we recommend that three phylogenetic species should be recognized, C. pusilla in the Chatham Islands, C. huegeli in the Snares Islands and C. aucklandica in the southern islands. The populations of C. aucklandica in the Auckland Islands, Antipodes Island and Campbell Island may warrant recognition as subspecies, and all should be managed as separate conservation units.     

Variation between laboratory populations of Encarsia formosa in their parasitization behavior on the host Bemisia tabaci

We tested the hypothesis that two populations of the parasitoid Encarsia formosa Gahan (Hymenoptera: Aphelinidae) differed in their behavioral interactions with the whitefly host Bemisia tabaci Gennadius (Homoptera: Aleyrodidae). The two wasp populations were studied because previous work suggested large differences between the populations in performance on this host. In this study the populations differed behaviorally in both the number of hosts encountered and their reactions to hosts once encountered. The population reared for many years on Trialeurodes vaporariorum Westwood (Homoptera: Aleyrodidae) that previously performed more poorly on B. tabaci had a higher host encounter rate but rejected hosts more frequently. The population reared for a number of years on B. tabaci encountered fewer hosts but accepted a higher percentage of hosts for oviposition. The number of parasitized hosts did not differ between the two populations, however. These data demonstrate that there are heritable differences between these two populations of asexual wasps in host-associated behavioral traits. These behavioral differences in host acceptance do not explain performance differences seen in the earlier study, however, possibly due to different conditions between the two experiments.     

Reproductive Isolation and Genetic Variation between Two “Strains” ofBracon hebetor(Hymenoptera: Braconidae)

Bracon hebetorSay(Hymenoptera: Braconidae) is known primarily as a parasitoid of pyralid moth larvae infesting stored grain. In the 1970s, a parasitoid identified asB. hebetorwas released for control ofHeliothis/Helicoverpaspp. (Lepidoptera: Noctuidae) on the island of Barbados. Because life-history traits of this parasitoid differed from those reported forB. hebetorfrom the United States, we conducted a series of laboratory experiments to determine whether this parasitoid was (i) a population ofB. hebetorthat attacks noctuids in the field or (ii) a different species fromB. hebetor.We confirmed thatHeliothis virescens(F.) was a more suitable host for the Barbados strain than forB. hebetor.However, a stored-grain infesting pyralid,Plodia interpunctella(Hübner), was a more suitable host for the Barbados strain than wasH. virescens.Reciprocal crosses between the Barbados strain andB. hebetorshowed that the two populations were reproductively isolated. No mating was observed during a series of 30-min observations of reciprocal crosses, and the crosses produced only male offspring. Examination of each female's spermatheca confirmed that females were not fertilized. Sequence analysis of a 517-bp fragment of the mitochondrial 16S rRNA gene revealed that two populations ofB. hebetorfrom our laboratory were identical but differed in sequence by 2% from the Barbados strain. Collectively, our results indicate that the Barbados strain is a distinct species fromB. hebetor.     

Geographic phenetic variation of two eastern-Mediterranean non-commensal mouse species, Mus macedonicus and M. cypriacus (Rodentia: Muridae) based on traditional and geometric approaches to morphometrics

We tested the hypothesis that skull shape within the genus Mus may vary with geographic location by assessing the extent and spatial distribution of phenotypic skull variation within and among two wild mouse species, M. macedonicus and M. cypriacus, using traditional and geometric morphometrics including a rather novel application of sliding semilandmarks. Shape was shown to be significantly correlated both with longitude and latitude in M. macedonicus, yet the correlation between morphometric and geographic distances was not significant, and morphometric differences between Asian and European populations were not higher than those within the particular continents. The phylogenetic signal was found to be stronger in dental characters than in cranial ones, however, overall concordance between the pattern of morphometric variation and the presumed history of M. macedonicus was rather weak. In both species, the dorsal and ventral sides of the skull were shown to covary in many aspects though there were also some differences between them, making the functional interpretation of these differences difficult. Discrimination between M. cypriacus and M. macedonicus as well as discrimination between two M. macedonicus subspecies was highly reliable using both traditional and geometric morphometric tools to analyze skull measurements.     

Genetic identification of larvae and juveniles reveals the difference in the spawning site among Cyprininae fish species/subspecies in Lake Biwa

To understand the differences in the spawning sites among Cyprininae fishes in Lake Biwa, we conducted periodic sampling of larvae and juveniles at three sites (irrigation ditch, St. 1; river, St. 2; and satellite lake, St. 3). On the basis of species/subspecies identification by using RAPD analysis, we examined the species composition of the larvae and juveniles at these three sampling sites. The number of specimens was 616, 68, and 117 at St. 1, St. 2, and St. 3, respectively. Based on morphological and genetic identification, the specimens were found to include nine fish species/subspecies, namely, Carassius auratus grandoculis, Carassius cuvieri, Carassius auratus langsdorfii, Cyprinus carpio, Sarcocheilichthys sp., Silurus asotus, Oryzias latipes, Odontobutis obscura obscura, and Rhinogobius sp. The species composition at the three sites also differed. Among the Cyprininae fishes, C. auratus grandoculis, C. auratus langsdorfii, and Cyprinus carpio were found in abundance at St. 1; C. cuvieri was not collected from St. 1 but was found at the other two sites, particularly St. 3. Among the other fishes, Rhinogobius sp. was collected at St. 1 and St. 3, whereas the other four occurred only at St. 1. These results suggest that the selection of spawning sites by C. cuvieri differs to a certain extent from that of the other Cyprininae fishes, and the irrigation ditch in the lake is an important habitat for the larvae and juveniles of native fish species.     

Genetic relationships among the Japanese and Korean striated spined loach complex (Cobitidae: Cobitis) and their phylogenetic positions

The striata complex, a group of spined loaches included in the genus Cobitis and characterized by a striped coloration pattern on the lateral midline, is distributed in rivers in northeastern Asia to western Japan. The complex comprises 2 continental species (Cobitis tetralineata and Cobitis lutheri) and 3 Japanese races of species rank (large race, middle race, and small race), the small race further comprising 6 local forms of subspecific rank (Tokai form, Biwa form, Yodo form, Sanyo form, San-in form, and Kyushu form). Previous karyological studies have revealed that the large race is an allotetraploid, the others being diploid. In this study, mitochondrial (mt) DNA analyses were conducted for 30 diploid populations of the Cobitis striata complex from Japan and Korea to examine: (1) their phylogenetic relationships and the position of the complex among the major lineages of Cobitis; and (2) the genetic relationships among the Japanese and Korean populations. The results, based on cytochrome b sequences (724 base pairs) analyzed with those of the main lineage of European and Japanese Cobitis, indicated that the striata complex should be considered as a monophyletic group, which evolved in northeastern Asia. Initially considered as a subspecies of Cobitis taenia, widely distributed from Europe to Asia, the striata complex does not have a sister-relationship with the former. Although the Korean species C. tetralineata was formerly believed to be closely related to the middle race in Japan, and a second continental species, C. lutheri, closely related to the Kyushu or San-in forms of the small race in Japan, the trees resulting from the present study revealed that the two Korean species were clustered with each other and separated from all Japanese races.     

Phylogeography and phylogeny of the epineritic cosmopolitan bonitos of the genus Sarda (Cuvier): inferred patterns of intra‐ and inter‐oceanic connectivity derived from nuclear and mitochondrial DNA data

Aim To reconstruct the phylogenetic relationships of the four species of the genus Sarda (Sarda sarda, Sarda orientalis, Sarda australis and Sarda chilensis) and their phylogeographic history in the context of historical and ecological biogeography. Also, to reconstruct within‐species phylogenetic relationships to test whether the North Atlantic and Mediterranean populations of Atlantic bonito (S. sarda) warrant subspecies status, and the validity of the allopatric northern and southern populations of eastern Pacific bonito (S. chiliensis), recognized as S. chiliensis lineolata and S. chiliensis chiliensis. Location Representative samples of all four Sarda species collected world‐wide were analysed. Methods Phylogenetic inference was carried out with neighbour‐joining, maximum parsimony and maximum likelihood, employing nucleotide sequences of the mitochondrial DNA (mtDNA) control region I (CR‐I) and of the single‐copy nuclear DNA (nDNA) Tmo‐4c4 gene. Analysis of molecular variance was used on the mtDNA data to estimate the extent of geographic population structuring. Results Gene trees derived from mtDNA and nDNA data yielded concordant phylogenies that support the monophyly of the genus Sarda. The following sibling pairs received strong statistical support: striped bonito (S. orientalis) with Australian bonito (S. australis), and Atlantic bonito (S. sarda) with eastern Pacific bonito (S. chiliensis). Furthermore, the origin of S. sarda mtDNA is paraphyletic with respect to S. chiliensis, and these results are indicative of introgression. The analysis of Tmo‐4c4 sequences corroborates the ancestral hybridization between these allopatric species. Comparisons of north‐west Atlantic and Mediterranean populations of S. sarda using mtDNA CR‐I data revealed substantial genetic differentiation. By contrast, no differences between the putative northern and southern allopatric subspecies of S. chiliensis were detected. Main conclusions The monophyly of the genus Sarda as indicated by morphology is corroborated using both molecular markers. However, molecular phylogenies depicted a paraphyletic relationship between S. sarda and S. chiliensis. This phylogeographical relationship is better explained by an ancestral introgression facilitated by trans‐Arctic contact during the Pleistocene. The pronounced genetic differentiation between S. sarda samples from the north‐west Atlantic and the Mediterranean is consistent with the differentiation of these two regions, but not with the amphi‐Atlantic speciation hypothesis. Finally, the S. chiliensis lineolata and S. chiliensis chiliensis subspecies status is not supported by the molecular data.     

Phylogeography of the Korean pine (Pinus koraiensis) in northeast Asia: inferences from organelle gene sequences

Range-wide genetic variation of Korean pine (Pinus koraiensis) was assessed using maternally inherited mtDNA and paternally inherited cpDNA for 16 natural populations throughout northeast Asia in order to study its phylogeographical history during the Quaternary. The cpDNA variation indicated that there was no difference between populations on the Asian continent and those in the Japanese archipelago. In contrast, the mtDNA variation indicated that there was significant difference between the populations from the two regions, with each region having a different lineage. The continental populations exhibited no diversity in the mtDNA examined despite the species’ current extensive range and large populations. Conversely, while the Korean pine is rare in Japan, the Japanese populations exhibited greater levels of mtDNA diversity (H _T?=?0.502). The higher mtDNA diversity and evidence from numerous Korean pine macrofossil remains dated to the Pleistocene and recovered various sites in Japan suggest that the Japanese archipelago once served as a refugium to a much larger Korean pine population with a more extensive range than is the case today. The presence of the single mtDNA haplotype across the Asian continent suggests that the present widespread populations could have expanded from a single refugium population after the last glacial periods.     

Morphological and molecular characterization of the Landes honey bee (<Emphasis Type="Italic">Apis mellifera</Emphasis> L.) ecotype for genetic conservation

A population of honey bees (Apis mellifera mellifera L.) with an annual colony brood cycle adapted to a locally abundant floral source in the Landes region of Southwest France is the subject of genetic conservation efforts. This population is maintained by local beekeepers in an area that experiences both an annual seasonal influx of non-local colonies and the permanent culture of imported stock. However, some colonies native to the Landes do not have the adapted brood cycle and their status as ecotypic are in question. The present study used morphology, mitochondrial DNA and microsatellites to characterize the endemic population and suggests further genetic conservation strategies. These methods yielded different degrees of discrimination of native and imported colonies and provided a powerful suite of tools for local resource managers. Colonies from the Landes could be differentiated from non-local French A. m. mellifera populations using morphometric analysis, and from non-native and reference populations using mtDNA and microsatellites. Seven morphological characters were identified by discriminant analysis as informative for delineating the Landes ecotype from other A. m. mellifera populations. Mitochondrial haplotypes for the population were characterized and five microsatellite loci were found to be informative in characterizing the Landes population. Asymmetric gene flow detected with microsatellite alleles was observed to be 5.5–5.9% from imported to native stocks of honey bees while introgression of native microsatellite alleles into imported colonies was 21.6%.     

3种无脊椎动物对近江牡蛎Crassostrea ariakensis和熊本牡蛎C. sikamea的捕食研究

捕食是影响牡蛎种群建立和牡蛎礁发育的重要生物因子之一。通过室内受控实验测定了日本蟳（Charybdis japonica）、脉红螺（Rapana venosa）和黄口荔枝螺（Thais luteostoma）对4组规格（W1：壳高10-20mm;W2：壳高20-30mm;W3：壳高30-40mm;W4：壳高>40mm）近江牡蛎（Crassostrea ariakensis）和熊本牡蛎（C.sikamea）的捕食偏好性和捕食效率。双因子方差分析结果表明,日本蟳对2种牡蛎的捕食效率没有显著性差异（P>0.05）,但牡蛎规格大小显著影响着日本蟳的捕食效率（P<0.05）,即日本蟳对W1组近江牡蛎的捕食效率显著高于W2和W4组（P<0.05）,W3组的被捕食效率介于中间（P>0.05）;日本蟳对W1组熊本牡蛎的捕食效率显著高于W2和W3组（P<0.05）,W4组的被捕食效率与其他处理组均没有显著性差异（P>0.05）。牡蛎种类（P=0.590）和规格大小（P=0.357）对脉红螺的捕食效率均无显著性影响,不同规格的两种牡蛎均呈现较低的被捕食效率。黄口荔枝螺对2种牡蛎的捕食效率无显著性差异（P=0.917）,但牡蛎规格大小显著影响其捕食效率（P=0.035）,即对W1组熊本牡蛎捕食效率显著高于其他3个规格组（P<0.05）,但其对不同规格近江牡蛎的捕食效率没有显著性差异（P>0.05）。2种牡蛎的壳厚与其壳高之间均存在极显著的正相关关系（P<0.001）。研究结果表明,3种无脊椎动物捕食者对近江牡蛎和熊本牡蛎并未表现出差异性的捕食偏好,但对不同规格牡蛎的捕食效率具有种间差异。