Geographical variation in host–ant specificity of the parasitic butterfly Maculinea alcon in Denmark

Abstract  1. Maculinea alcon uses three different species of Myrmica host ants along a north–south gradient in Europe. Based on this geographical variation in host ant use, Elmes et al . (1994) suggested that M. alcon might consist of three or more cryptic species or host races, each using a single and different host-ant species.
2. Population-specific differences in allozyme genotypes of M. alcon in Denmark ( Gadeberg & Boomsma, 1997 ) have suggested that genetically differentiated forms may occur in a gradient across Denmark, possibly in relation to the use of different host ants.
3. It was found that two host-ant species are indeed used as hosts in Denmark, but not in a clear-cut north–south gradient. Furthermore, specificity was not complete for many M. alcon populations. Of five populations investigated in detail, one used primarily M. rubra as a host, another exclusively used M. ruginodis , while the other three populations used both ant species. No population in Denmark used M. scabrinodis as a host, although this species was present in the habitat and is known to be a host in central and southern Europe.
4. In terms of number of parasites per nest and number of nests parasitised, M. rubra seems to be a more suitable host in populations where two host species are used simultaneously. Host-ant species has an influence on caterpillar size but this varies geographically. Analyses of pupae did not, however, show size differences between M. alcon raised in M. rubra and M. ruginodis nests.
5. The geographical mosaic of host specificity and demography of M. alcon in Denmark probably reflects the co-evolution of M. alcon with two alternative host species. This system therefore provides an interesting opportunity for studying details of the evolution of parasite specificity and the dynamics of host-race formation.     

Microsatellite markers for the large blue butterflies Maculinea nausithous and Maculinea alcon (Lepidoptera: Lycaenidae) and their amplification in other Maculinea species

We developed microsatellite markers for Maculinea nausithous and Maculinea alcon, two of five species of endangered large blue butterflies found in Europe. Two separate microsatellite libraries were constructed. Eleven markers were developed for M. nausithous and one for M. alcon. The primers were tested on both species as well as on the three other European Maculinea species. The number of alleles per locus ranged from two to 14. These markers will be useful tools for population genetic studies of Maculinea species.     

Pattern of genetic differentiation in the Maculinea alcon species group (Lepidoptera, Lycaenidae) in Central Europe

The taxonomic status of Alcon Blues living in Central and Western Europe (conventionally: Maculinea alcon and Maculinea rebeli ) is quite confused. Some authors distinguish them as separate species of the M. alcon species group, while others consider them as subspecies or simply ecological forms. Our aim was to study the pattern of genetic differentiation among several populations of these taxa with reference to their taxonomic position. Imagoes were collected from 27 localities in Central Europe between 1999 and 2003. Samples originated from four regions: northern Hungary, central Hungary, Romania: Transylvania and Slovenia. Enzyme polymorphism was analysed using polyacrylamide gel electrophoresis. In all samples 16 enzyme loci were studied. In the analysis of the data, F -statistics was computed and the total genetic variation was partitioned into within and between population components. Nei's genetic distances were calculated and UPGMA dendrogram was constructed on the basis of the distance matrix. Hierarchical F -statistics and amova was computed to study the pattern of genetic differentiation among the samples. Principal component analysis (PCA) was also carried out using the allele frequencies of the samples. The results of all analyses indicated a high level of differentiation among the samples. The differences among the samples collected in different years from the same population accounted for a considerable amount of the between sample variation. The distribution of the between sample variation did not exhibit a species pattern. The results of amova and PCA indicated that the geographic pattern was slightly more expressed in the between sample variation compared with the species pattern of it. These results seem to contradict with the conventional taxonomical subdivision.     

Population structure of a large blue butterfly and its specialist parasitoid in a fragmented landscape

Habitat fragmentation may interrupt trophic interactions if herbivores and their specific parasitoids respond differently to decreasing connectivity of populations. Theoretical models predict that species at higher trophic levels are more negatively affected by isolation than lower trophic level species. By combining ecological data with genetic information from microsatellite markers we tested this hypothesis on the butterfly Maculinea nausithous and its specialist hymenopteran parasitoid Neotypus melanocephalus. We assessed the susceptibility of both species to habitat fragmentation by measuring population density, rate of parasitism, overall genetic differentiation (theta(ST)) and allelic richness in a large metapopulation. We also simulated the dynamics of genetic differentiation among local populations to asses the relative effects of migration rate, population size, and haplodiploid (parasitoid) and diploid (host) inheritance on metapopulation persistence. We show that parasitism by N. melanocephalus is less frequent at larger distances to the nearest neighbouring population of M. nausithous hosts, but that host density itself is not affected by isolation. Allelic richness was independent of isolation, but the mean genetic differentiation among local parasitoid populations increased with the distance between these populations. Overall, genetic differentiation in the parasitoid wasp was much greater than in the butterfly host and our simulations indicate that this difference is due to a combination of haplodiploidy and small local population sizes. Our results thus support the hypothesis that Neotypus parasitoid wasps are more sensitive to habitat fragmentation than their Maculinea butterfly hosts.     

Genetic differentiation among the Maculinea species (Lepidoptera: Lycaenidae) in eastern Central Europe

The present study aimed to analyse the level of genetic variation in the eastern Central European (Slovenia, Hungary, and Romania/Transylvania) populations of the Large Blues ( Maculinea ) to analyse the pattern of differentiation both between and within the species. One objective was to compare the level of differentiation between the two disputed species ( Maculinea alcon and Maculinea rebeli ) with that among the other species. Imagos were collected from 23 localities in eastern Central Europe in 2002. Enzyme polymorphism was analysed using polyacrylamide gel electrophoresis. Fourteen enzyme loci were studied in all samples. In the analysis of the data, F -statistics and Nei's genetic distances were calculated and a dendrogram (unweighted pair group method with arithmetic mean) was constructed on the basis of the distance matrix. A multivariate analysis of variance was performed to study the pattern of genetic differentiation among the samples. Principal component analysis analysis was also carried out using the allele frequency data of the samples. Our results indicated that the large blues are generally less polymorphic than other European lycaenid butterflies studied. At the same time, the level of genetic differentiation was high, even among local populations within the species. A low level of genetic variation within the populations coupled with strong differentiation among them implies the effect of genetic drift. Strong genetic differentiation of four Maculinea species ( M. alcon , Maculinea teleius, Maculinea nausithous , and Maculinea arion ) was confirmed. Significant differentiation was not found between M. alcon and M. rebeli .  © 2007 The Linnean Society of London, Biological Journal of the Linnean Society , 2007, 91 , 11–21.     

Comparison of genetic population structure of the large blue butterflies Maculinea nausithous and M. teleius

We investigated the genetic population structure of two rare myrmecophilous lycaenid butterflies, Maculinea nausithous and M. teleius, which often live sympatrically and have similar biology. In Europe, both species occur in highly fragmented populations and are vulnerable to local extinction. The proportion of variable allozyme loci, average heterozygosity and genetic differentiation among populations was higher in M. nausithous than in sympatrically living M. teleius populations. We hypothesise that the differences in heterozygosity are mainly due to the known higher efficiency of typical host ant nests in rearing M. nausithous pupae compared to M. teleius pupae. This implies a larger probability of larval survival in M. nausithous, which buffers populations against environmental and demographic stochasticity. In contrast, the lower carrying capacity of ant nests in rearing M. teleius pupae requires higher nest-densities and makes M. teleius populations more prone to losing genetic variation through drift if this condition is not fulfilled. The single investigated Russian population of M. teleius showed much higher levels of heterozygosity than any of the Polish populations, suggesting a more viable and still intact metapopulation structure.     

利用InDel标记分析中国香菇菌株的遗传多样性与群体结构

通过对5个香菇菌株重测序,以香菇L808-1菌株的全基因组序列为参考基因组,分析了这些菌株中插入/缺失（InDel）标记位点在香菇基因组10条染色体上的分布,并筛选了插入/缺失碱基数≥15的位点,合成了449对InDel标记引物。经过PCR和电泳检测,其中237对引物条带清晰。最终筛选出107个PIC≥0.3的标记作为核心InDel标记对来自国内的44份香菇菌株进行遗传多样性分析。聚类分析显示栽培菌株和野生菌株各自聚为一支,所选香菇菌株间存在明显的群体分层。群体结构分析显示香菇种质资源可分为4个亚群,主成分分析显示香菇菌株之间的位置及距离与聚类分析和群体结构分析结果相符。香菇InDel分子标记的开发与应用,为香菇核心种质的构建和种质资源育种引用提供了基础。     

Dispersal and gene flow in the rare, parasitic Large Blue butterfly Maculinea arion

Dispersal is crucial for gene flow and often determines the long‐term stability of meta‐populations, particularly in rare species with specialized life cycles. Such species are often foci of conservation efforts because they suffer disproportionally from degradation and fragmentation of their habitat. However, detailed knowledge of effective gene flow through dispersal is often missing, so that conservation strategies have to be based on mark–recapture observations that are suspected to be poor predictors of long‐distance dispersal. These constraints have been especially severe in the study of butterfly populations, where microsatellite markers have been difficult to develop. We used eight microsatellite markers to analyse genetic population structure of the Large Blue butterfly Maculinea arion in Sweden. During recent decades, this species has become an icon of insect conservation after massive decline throughout Europe and extinction in Britain followed by reintroduction of a seed population from the Swedish island of Öland. We find that populations are highly structured genetically, but that gene flow occurs over distances 15 times longer than the maximum distance recorded from mark–recapture studies, which can only be explained by maximum dispersal distances at least twice as large as previously accepted. However, we also find evidence that gaps between sites with suitable habitat exceeding ～20 km induce genetic erosion that can be detected from bottleneck analyses. Although further work is needed, our results suggest that M. arion can maintain fully functional metapopulations when they consist of optimal habitat patches that are no further apart than ～10 km.     

Genetic diversity and population structure of Elytrigia pycnantha (Godr.) (Triticeae) in Mont Saint-Michel Bay using microsatellite markers

During the last decade, an invasive wheatgrass species (Elytrigia pycnantha) has colonized the low salt marshes of the Mont Saint Michel Bay resulting in an accelerated change in the vegetation. This study was conducted using microgeographical genetic diversity in order to understand the genetic structure of this invasive and clonal species. Genetic variation and population structure of fifteen populations collected in high and low marsh habitats around the Bay were analyzed using five microsatellite loci. Because E. pycnantha is an allohexaploid, the application of standard genetic diversity statistics was not possible; we chose to summarize genetic diversity using statistics calculated from banding phenotypes. The mean number of alleles per locus was 10.2, the mean number of different alleles per sample was 6.87. The mean number of allelic phenotypes across all populations was 7.21. The mean value of genetic diversity for the species, calculated as the average number of alleles by which pairs of individuals differ, was H's = 1.91 and H't = 2.04. Little genetic differentiation among populations was detected (0.067). The association between pairwise genetic differentiation and geographic distances exhibited no evidence for isolation by distance. A geographical pattern of population differentiation, where a single population GI was clearly separated from the remaining population groups (considered as a metapopulation), was revealed by principal component analysis (PCA), and we propose that this is because GI represents a new genotype.     

Lessons from the reintroduction of Maculinea teleius and M. nausithous in the Netherlands

Details of a reintroduction of Maculinea teleius (scarce large blue butterfly) and Maculinea nausithous (dusky large blue butterfly) into a nature reserve in the Netherlands are given. The introduced population of M. teleius expanded during the first three years. In contrast, the newly established population of M. nausithous declined in the year after the reintroduction but expanded later. After a considerable increase in numbers, this species can nowadays be seen in two subpopulations: one in and one outside the nature reserve. Although the results are quite positive with respect to the numbers of butterflies, some alarming features have also been found. Both species, but especially M. teleius, have a very low mean minimal lifetime, which makes them more susceptible to stochastic catastrophes. While the area populated by M. nausithous is still expanding, M. teleius can only be found on the meadow where it was released and has not dispersed at all. The possible consequences of reintroductions are discussed. © Rapid Science Ltd. 1998     

Genetic diversity and population structure of an insular tree, Santalum austrocaledonicum in New Caledonian archipelago

We present a study of the genetic diversity and structure of a tropical tree in an insular system. Santalum austrocaledonicum is endemic to the archipelago of New Caledonia and is exploited for oil extraction from heartwood. A total of 431 individuals over 17 populations were analysed for eight polymorphic microsatellite loci. The number of alleles per locus ranged from 3 to 33 and the observed heterozygosity per population ranged from 0.01 in Mare to 0.74 in Ile des Pins. The genetic diversity was lowest in the most recent islands, the Loyautes, and highest in the oldest island, Grande Terre, as well as the nearby small Ile des Pins. Significant departures from panmixia were observed for some loci-population combinations (per population FIS = 0-0.03 on Grande-Terre and Ile des Pins, and 0-0.67 on Loyautes). A strong genetic differentiation among all islands was observed (FST = 0.22), and the amount of differentiation increased with geographic distance in Iles Loyaute and in Grande Terre. At both population and island levels, island age and isolation seem to be the main factors influencing the amount of genetic diversity. In particular, populations from recent islands had large average FIS that could not be entirely explained by null alleles or a Wahlund effect. This result suggests that, at least in some populations, selfing occurred extensively. Conclusively, our results indicate a strong influence of insularity on the genetic diversity and structure of Santalum austrocaledonicum.     

Genetic variation and population structure of the mosquito Anopheles jeyporiensis in southern China

Genetic differentiation among populations of Anopheles jeyporiensis was examined using 76 mtDNA COII sequences from 16 sites throughout southern China and northern Vietnam. The COII sequences are AT-rich (74.58%) and reveal high levels of diversity with 39 of 685 sites polymorphic and 50 different haplotypes present. Genetic variation is high within populations and significant geographical structure was detected at both population and regional levels. In the larger samples, the distributions of haplotypes suggest recent population expansion.     

Genetic variation and population structure ofCarex breviculmis (Cyperaceae) in Korea

We determined the genetic diversity and population structures ofCarex breviculmis (Cyperaceae) populations in Korea, using genetic variations at 23 allozyme loci.C. breviculmis is a long-lived herbaceous species that is widely distributed in eastern Asia. A high level of genetic variation was found in 15 populations. Twelve enzymes revealed 23 loci, of which 11 were polymorphic (47.8%). Genetic diversity at the speciesand population levels were 0.174 and 0.146, respectively. Total genetic diversity (H_T = 0.363) and within-population genetic diversity (H_s = 0.346) were high, whereas the extent of the population divergence was relatively low (G_ST = 0.063). Deviation from random mating (Fis) within the 15 populations was 0.206. An indirect estimate of the number of migrants per generation(Nm = 3.69) indicated that gene flow was extensive among Korean populations of this species. Analysis of fixation indices revealed a substantial heterozygote deficiency in some populations and at some loci. Genetic identity between popu-lations was high, exceeding 0.956.     

Genetic variation and population structure in the endangered greater horseshoe bat Rhinolophus ferrumequinum

Following a dramatic decline last century, the British population of the endangered greater horseshoe bat Rhinolophus ferrumequinum is highly fragmented. To examine the consequences of fragmentation and limited dispersal on patterns of genetic structure and variation, we used microsatellite markers to screen bats from around 50% of the known maternity colonies in Britain, and two areas from continental Europe. Analyses revealed that Welsh and English colonies were genetically isolated. This, and lower variability in Britain than north France, may result from either genetic drift, or the species' colonization history. Gene flow among most neighbouring colonies was not generally restricted, with one exception. These findings have important implications for the ongoing conservation management of this species.     

欧洲刺槐种源群体遗传结构和多样性

对来自欧洲和美国的 18个刺槐种源子代进行了等位酶分析。可进行遗传分析的 7个酶系统 (Amy,Fe,L ap,Idh,Mdh,6 Pgd,Skd)中有 14个基因位点 ,其中 12个位点具有多态性。每个多态位点平均等位基因数 (A/L )变化在 1.5 6～ 3.6 7之间 ,平均基因型数 (G/L)变化在 1.6 1～ 7.11之间 ,平均等位基因有效数目 (Ae)变化在 1.0 2～ 2 .5 0之间 ,预期杂合度 (H e)变化在0 .0 2～ 0 .5 6之间。不同种源群体之间也存在较大的遗传差异 ,在 8个德国种源中 ,各群体的 A、Ae、和 H e等相对较小 ,但不同群体间差异较大。各位点等位基因频率在不同种源群体间变化也较大 ,表明德国各种源群体内遗传变异相对较小 ,但群体间差异较大。来自匈牙利和斯洛伐克的 8个种源群则相反 ,各群体的 A、Ae、和 H e等相对较大 ,而不同种源群体间差异则较小 ,各位点等位基因频率在种源群体间变化相对一致 ,表明这两个国家的种源群体内变异较大 ,但不同种源群体间差异较小。欧洲的刺槐种源并未形成明显的地理变异模式 ,而且欧洲的种源和来自原产地的美国种源相比 ,没有发现明显的差异。经过 Hardy-Weinberg平衡检测证明 ,88.4 1%位点符合 H- W遗传平衡 ,表明各群体基因频率和基因型频率保持较高的稳定性 ,且种源内的变异大于种源间变异 ,94 .     

REVIEW: The recent distribution of the European Maculinea species

The genus Maculinea is confined to the Palaearctic region. Four species occur from Central Europe to China and/or Japan, while M. rebeli is probably restricted to Europe. Although within many Western European countries the distribution of the species is well known, there are still many questions. The exact status of some of the species is still unclear and the amount of decline in this century is unknown. In Asia, especially within the nations of the former USSR, the distributions of species are even less well known and as a basis for good research and effective nature conservation, knowledge on these subjects is needed. © Rapid Science Ltd. 1998     

Genetic diversity and population structure of five Ethiopian chicken ecotypes

This study aimed to analyse the genetic diversity and population structure of five Ethiopian chicken ecotypes (N = 155), which were compared with six commercial purebreds (N = 180). For the analysis of genetic diversity, 26 AVIANDIV microsatellite markers were used. The number of alleles in Ethiopian ecotypes ranged from 2 to 19 per locus, with a mean of 6.1. The average observed heterozygosity within ecotype varied between 0.53 and 0.57. The overall heterozygote deficiency (F(IT)) in Ethiopian ecotypes was 0.124 ± 0.037. Over 68% of F(IT) was because of within-ecotype deficiency (F(IS)). In the phylogenetic tree, Ethiopian ecotypes clustered into two groups. The analysis of the relationship between populations using the structure program provided further evidence for the occurrence of at least two subgroups in the Ethiopian ecotypes. Findings of this study may provide the background for future studies to identify the origin of the two gene pools representing the Ethiopian chicken ecotypes and to characterize the gene variants influencing economically important traits.