A chemical perspective on the evolution of variation in Eucalyptus globulus

It is becoming increasingly easy to generate genotypic data but much harder to gather an equivalent amount of phenotypic information, particularly for chemical traits. In this study of Eucalyptus globulus ssp. globulus, we measured about 60 chemical leaf traits of trees growing in a common garden to address the following questions: (1) how much variation is there between geographic regions, populations within regions and within populations? (2) How do chemical traits vary over the species’ geographic range? (3) If so, does E. globulus ssp. globulus exhibit distinct chemotypes – plants that are morphologically similar but which differ chemically? (4) Are the affinities between E. globulus ssp. globulus and closely related subspecies apparent in the chemical variation? Variation among trees within populations contributed most variation in leaf chemistry followed by variation between geographic regions. For many traits, variation among populations within proposed races and variation among proposed races within geographic regions explained little of the total variation. There was a cline in the concentration of secondary chemicals with the lowest concentrations in Tasmanian populations and the highest in those from eastern Victoria, with intermediate concentrations in populations from Bass Strait Islands. We identified three chemotypes, characterised by specific terpenes and formylated phloroglucinol compounds. The frequency of occurrence of these chemotypes showed a geographic pattern also, with “chemotype 1” predominating in Tasmania, while “chemotypes 2 and 3” occurred at highest frequency in eastern Victoria. We suggest that the chemotypes reflect introgression between E. globulus ssp. globulus and the three closely related subspecies – E. globulus ssp. bicostata, E. globulus ssp. maidenii and E. globulus ssp. pseudoglobulus. Although the formation of land-bridges with fluctuating sea levels has no doubt shaped the evolutionary history of all four subspecies, we propose that the migratory swift parrot (Lathamus discolor), an important pollinator and a species closely associated with E. globulus, has helped shape the evolution of the four tree subspecies.     

Biogeography and designatable units of <Emphasis Type="Italic">Bombus occidentalis</Emphasis> Greene and <Emphasis Type="Italic">B. terricola</Emphasis> Kirby (Hymenoptera: Apidae) with implications for conservation status assessments

Conservation action for species of concern requires that “designatable units” (e.g., species, subspecies, geographic races, genetically distinct forms) are clearly defined, or that the species complex is treated as a whole. Several species of bumble bee are currently threatened, and some of these have cryptic colouration (resembling other species), or form complexes that vary considerably in colour patterning. Here we address the taxonomy and distribution of Bombus occidentalis Greene and B. terricola Kirby, both of which are currently of conservation concern in North America. Bombus occidentalis includes two apparently monophyletic groups of COI barcode haplotypes (recently considered as subspecies) with ranges mostly separated by that of their sister species, B. terricola. The southern B. o. occidentalis ranges throughout the western United States and into western Canada from southern Saskatchewan and Alberta, and throughout British Columbia north to ca. 55°N; the northern B. o. mckayi Ashmead, is restricted to north of this in British Columbia, westernmost Northwest Territories, Yukon Territory and Alaska. Bombus o. mckayi exists, as far as is known, only with a “banded” colour pattern. By contrast, B. o. occidentalis occurs in both banded and non-banded colour patterns, although the southern banded colour pattern is geographically isolated from the northern subspecies. Bombus o. occidentalis has declined throughout its range, perhaps due in part to exposure to novel parasites. Despite having similar levels of parasitism (ca. 40 %) as the southern subspecies, B. o. mckayi appears to have stable populations at present. There is therefore compelling evidence that the two subspecies should be distinguished for conservation and management purposes. We present the evidence for their distinction and provide tools for subspecies recognition.     

Polyploid races of earthworms (Lumbricidae, Oligochaeta) in the East European plain and Siberia

The distribution of polyploid races of earthworms in the East European plain and Siberia was analyzed. Amphimictic autopolyploid races of two species of the Asian genus Eisenia, E. nordenskioldi and E. atlaviniteae, are widespread in Siberia, from its southern boundary to the arctic region, while polyploid Lumbricidae in the East-European plain, except for the Volga region, are represented mainly by parthenogenetic forms of other genera. This is presumably related to differences in the Pleistocene environmental history between the two adjacent geographic regions of Eurasia.     

Ranges and cold hardiness of two earthworm subspecies (Eisenia nordenskioldi, Lumbricidae, Oligochaeta)

The ranges of two earthworm subspecies, Eisenia nordenskioldi nordenskioldi (Eisen 1879) and E. n. pallida Malevi 1956, differ in area and partially overlap. E. n. nordenskioldi populates the entire Asian Russia and eastern regions of the Russian Plain, from the lower reaches of the Volga and Don rivers to the Arctic Ocean coasts, while E. n. pallida has not expanded to the Asian permafrost zone and does not occur in European Russia and in the Urals. These subspecies “hold the record” in cold hardiness: the worms and cocoons of the nominotypical subspecies withstand temperatures down to ?34 and ?40°C, and those of E. n. pallida, to ?28 and ?23°C, respectively. Hence, their distribution is independent of subzero temperatures, and their ability to overwinter at any phase of the life cycle makes them also independent of heat supply during the summer period. Differences in geographic range may also be due to biological features of the subspecies. The nominotypical subspecies feeds belongs to the epiendogeic morphoecological type (feeding on the ground surface), whereas E. n. pallida is a true endogeic earthworm. Both subspecies have similar requirements for soil acidity; however, conditions in coarse-humus organomineral horizons of frozen soils appear to be unfavorable for E. n. pallida, which accounts for the absence of this subspecies in the permafrost zone.     

On the reality of local and ecological races in lymnaeid snails (Mollusca,Gastropoda, Lymnaeidae)

The reality of ecological and local races was investigated in two widespread Palearctic species of lymnaeid snails (Lymnaea stagnalis and Radix auricularia). Several methods of statistical analysis were used, including two-way ANOVA, cluster analysis, and discriminant analysis for six plastic shell characters. It was shown that none of the methods used could convincingly demonstrate that ecological and local races were present in the studied species. Even in cases when statistically significant differences among the populations in the morphology of shells were revealed, these differences were very small and did not correspond to the meaning that was put into the concept of “race” by malacologists in the past. Perhaps, the formation of such races in pond snails is possible only in case of populations being formed in suboptimal conditions, for example, in thermal springs or at large depths. This being the case, the distinguishing of races requires using other shell characters, both quantitative and qualitative ones.     

Facing the Heat: Thermoregulation and Behaviour of Lowland Species of a Cold-Dwelling Butterfly Genus,Erebia

Understanding the potential of animals to immediately respond to changing temperatures is imperative for predicting the effects of climate change on biodiversity. Ectothermic animals, such as insects, use behavioural thermoregulation to keep their body temperature within suitable limits. It may be particularly important at warm margins of species occurrence, where populations are sensitive to increasing air temperatures. In the field, we studied thermal requirements and behavioural thermoregulation in low-altitude populations of the Satyrinae butterflies Erebia aethiops, E. euryale and E. medusa. We compared the relationship of individual body temperature with air and microhabitat temperatures for the low-altitude Erebia species to our data on seven mountain species, including a high-altitude population of E. euryale, studied in the Alps. We found that the grassland butterfly E. medusa was well adapted to the warm lowland climate and it was active under the highest air temperatures and kept the highest body temperature of all species. Contrarily, the woodland species, E. aethiops and a low-altitude population of E. euryale, kept lower body temperatures and did not search for warm microclimates as much as other species. Furthermore, temperature-dependence of daily activities also differed between the three low-altitude and the mountain species. Lastly, the different responses to ambient temperature between the low- and high-altitude populations of E. euryale suggest possible local adaptations to different climates. We highlight the importance of habitat heterogeneity for long-term species survival, because it is expected to buffer climate change consequences by providing a variety of microclimates, which can be actively explored by adults. Alpine species can take advantage of warm microclimates, while low-altitude grassland species may retreat to colder microhabitats to escape heat, if needed. However, we conclude that lowland populations of woodland species may be more severely threatened by climate warming because of the unavailability of relatively colder microclimates.     

Concepts of macro- and microevolution as related to the problem of origin and global expansion of the plague pathogen Yersinia pestis

The relationship between macro- and microevolutionary processes is considered with reference to the ecological scenario of the origin of the plague pathogen and its subsequent natural and anthropogenic global expansion. The macroevolutionary transformation of the ancestral pseudotuberculosis microbe clone into the initial plague microbe Yersinia pestis tarbagani occurred in Central Asia at the end of the Late Pleistocene by a “vertical” Darwinian way in an inadaptive heterothermal continual intermediate environment—the Mongolian marmot Marmota sibirica—flea Oropsylla silantiewi system—via a sequence of unstable and currently extinct intermediate forms. Its natural geographic expansion on the “oil spot” principle in the postglacial time led to the microevolutionary formation of 20–30 hostal subspecies circulating in populations of the background species of burrowing rodents and pikas in arid areas of Eurasia. The intercontinental spread of the “marmot” and “rat” pathogen subspecies in the past few centuries has been exclusively anthropogenic, with the involvement of synanthropic (ship) rats.     

The karyology of the Common shrew, Sorex araneus Linné, 1758 (Insectivora, Soricidae) in southwestern Germany

Presented is the karyotype of Sorex araneus from 4 trapping sites in southwestern Germany. From this species nearly 20 chromosomal races have so far been described. In the study area autosomal numbers of 2n_a= 22–24 were recorded. The characteristical metacentrics jl, hi, gm, kr and the acrocentrics n, o, p, q were identified by G-banding. The element kr shows Robertsonian polymorphism. The metacentrics only allow a classification of the studied populations as chromosomal race “Vaud” from Switzerland. The postglacial recolonization and the possible presence of other chromosomal races in the central and northern parts of Germany are briefly discussed. Different selection pressures act on metacentrics and acrocentrics in central populations of a chromosomal race in contrast to those living in contact zones of different chromosomal races. It is suggested that the smaller autosomal arms are subject to weaker selection pressure to be fixed as metacentrics.     

Hybridization of Races of Heterodera glycines

Progeny from single females of four known races of Heterodera glycines Ichinohe were used to establish relatively uniform populations. Single females from these populations were mated with males of other races in all possible combinations to study compatibility and inheritance patterns. When race 1 or 3 was crossed with either race 2 or 4, there was a significant reduction in number of females and a greater number of eggless females than in crosses of races 1 × 3 and 2 × 4. More females matured and fewer were eggless when matings were of the same race. Parasitic capabilities of races 2 and 4 were dominant or partially dominant over those of races 1 and 3, based on parasitism of F₁ hybrids. Segregation patterns were generally similar for reciprocal crosses between races. There appeared to be either one or two major genes segregating for parasitism of ''Pickett'' soybean in the different crosses. A hybrid isolate (race 3 × 4) that differed in parasitic capability from the four known races produced as many females on the resistant soybean genotype, PI 90,763, as on the susceptible Lee cultivar. Those data indicate that isolates of H. glycines with a different parasitic capability may develop from gene recombination.     

Searching for the glacial refugia of Erebia euryale (Lepidoptera,Nymphalidae) – insights from mtDNA‐ and nDNA‐based phylogeography in the Western Carpathians

The refugial history and postglacial re‐colonization routes of Western Carpathian insects are insufficiently understood. Therefore, we investigated the spatio‐genetic structure (phylogeography) of Western Carpathian populations of Erebia euryale (Esper, 1805) (Lepidoptera, Nymphalidae) and inferred their colonization routes over the postglacial period. Our results provide new insights into the phylogeography and origin of Erebia euryale in the rarely studied region of the Western Carpathian Mountains. Their phylogeography, including glacial refugia and Pleistocene expansion routes, was reconstructed based on two mitochondrial (COI and CR) and three nuclear markers (CAD, MDH and IDH). Statistical parsimony networks showed the following geographic coherences: (1) populations from Romania and the Bukovské Mountains (Kremenec) grouped together; (2) a ?ergov group containing populations only from the ?ergov Mountains; (3) a Volovské Mountains group with populations from Koj?ovská ho?a and Slovak Paradise grouped together, most likely due to the lack of geographic isolation between the areas; (4) haplotypes characterized from the Volovské Mountains populations were widespread. Comparisons of Western Carpathian E. euryale COI‐haplotypes with haplotypes from the Southern Carpathians and Balkans suggest that the refugial areas were located in south‐eastern Europe in the Balkan region and Southern Carpathians. We also hypothesize possible central European contact zones in Slovakia for E. euryale in the Western Carpathians. Our results indicate that the Western Carpathians could have served as one of the contact zones between Eastern and Western populations, and additionally as an extra refugium in the southern part of the Volovské Mountains for populations also occurring in Czech mountain regions.     

MORPHOLOGICAL AND PHYSIOLOGICAL DIFFERENTIATION OF PHORADENDRON POPULATIONS IN TEXAS

Investigation of the morphology and physiology of the mistletoe, Phoradendron tomentosum subsp. tomentosum, in Texas reveals that the subspecies is differentiated into at least two ecological races, one in north central Texas, the other in south central Texas. The races differ in leaf length/width ratio, fruit diameter, seed set, spike internode length, freeze tolerance, and flavonoid patterns. Clines occur in leaf length/width ratio and fruit diameter between the races, and these characteristics are negatively correlated. The northern race generally exhibits greater freeze tolerance than the southern race. Field observations, herbarium specimens, and a collection of fresh specimens from northeastern Mexico indicate that a third race in the subspecies may exist there. Racial variation within the subspecies appears to permit it to occupy a diversity of habitats. Morphological and physiological patterns within the two Texas races suggest that introgressive hybridization has occurred between them, allowing for the occupation of intermediate habitats.     

Susceptibility of Soybean Introductions to Races 1, 2, 3, and 4 of Heterodera glycines

Thirteen soybean plant introduction (PI) lines, selected for their apparent susceptibility to Heterodera glycines, were compared with cultivar Lee 74 as hosts of H. glycines races 1, 2, 3, and 4. Race 3 produced the highest average number of females of the four races. Compared to Lee 74, more (P = 0.05) females of H. glycines race 1 were extracted from eI 274420, PI 274423, and PI 317333; PI 86457 had more females of H. glycines race 2; and PI 86443, PI 86457, PI 261467, PI 274420, PI 274421, and PI 274423 had more females of H. glycines race 3. Similar numbers of females of H. glycines race 4 developed on all of the soybean lines and Lee 74. PI 274421, PI 274420, or PI 196159 could provide a more or equally susceptible host for H. glycines races 1, 2, 3, and 4 than Lee 74. One of these three lines could be substituted for Lee as the standard susceptible cultivar in the race determination test.     

Gene flow between alien and native races of the holoparasitic angiosperm Orobanche minor (Orobanchaceae)

The holoparasitic angiosperm Orobanche minor parasitizes a diverse range of flowering plants from at least 16 orders in both the monocots and eudicots. However, populations of O. minor show host specificity at a local level. Our previous work identified the potential for host specificity to act as a catalyst for genetic divergence among populations of O. minor. Here we have extended this investigation by sampling populations from multiple hosts, across a broad geographic range. Sequence characterised amplified region (SCAR) data identified an exotic host-generalist lineage and a native host-specialist lineage of O. minor, suggesting genetic structure in this species is defined by both host specificity and geography. In addition, host-range overlap, discordant tree topologies, and cryptic morphology indicate the presence of gene flow between alien races and endemic populations. Therefore, repeated introductions of alien races of O. minor from disparate sources leading to introgression with native populations, and cryptic race formation, seem to have contributed to the taxonomic confusion associated with this species. We speculate that radiations associated with broad host range and divergent host ecologies may have promoted the unusually wide geographic distribution and diversification of this species. Finally, evidence of multiple shifts to exotic hosts, coupled with the predicted northward shift in climatic suitability, identify the potential for range expansion in alien races of O. minor, which may threaten nationally scarce native taxa with genetic assimilation. Our phylogenetic analysis provides a framework for identifying host races in Orobanche with a view to setting conservation priorities.     

MITOCHONDRIAL DNA PHYLOGEOGRAPHY OF HOST RACES OF THE GOLDENROD BALL GALLMAKER,EUROSTA SOLIDAGINIS (DIPTERA: TEPHRITIDAE)

We determined the phylogenetic relationships and geographic distribution of mitochondrial haplotypes of two host races of the tephritid fly Eurosta solidaginis, a gallmaker that attacks species of goldenrod (Solidago). We performed a preliminary survey by sequencing 492 bp from the 3′ ends of the mitochondrial cytochrome oxidase I and II subunits from a single individual from eight S. gigantea- and 10 S. altissima-associated populations across their range in eastern North America and from two outgroup species, Eurosta comma (two populations) and E. cribrata. Eurosta solidaginis haplotypes fell into two groups (“E” and “W” clades), which differed by four substitutions, one of which occurred within the recognition site of the DdeI restriction enzyme. We used the presence or absence of the restriction site to survey a total of 11 S. gigantea (20 individuals) and 20 S. altissima (43 individuals) host-race populations. All gigantea-fly haplotypes regardless of geographic origin carried the E-clade haplotype, whereas altissima-fly haplotypes were geographically partitioned. Altissima flies east of Michigan were of haplotype E, whereas those west of Michigan were of haplotype W, with mixed populations found in lower Michigan. These patterns confirm an earlier allozyme survey that suggested that S. altissima is the ancestral host for the gallmaker, but also suggest that the gigantea fly populations were derived from eastern U.S. altissima fly populations. The data support the conclusions of behavioral and ecological studies indicating that the shift to the derived host was facilitated by escape from natural enemies.     

Distribution and ecology of the earthworm Eisenia nordenskioldi pallida (Oligochaeta,Lumbricidae) dominant in southern Siberia and the Russian Far East

A literature review and the results of re-examination of collections of the earthworm Eisenia nordenskioldi are presented. Peculiarities of the geographic and habitat distribution, as well the ecology of the diploid subspecies E. n. pallida, originally described as a non-pigmented form of E. nordenskioldi, are analyzed. E. n. pallida inhabits mainly the south of Siberia and the Russian Far East, penetrating as far northwards as the forest-tundra zone along the valleys of large rivers. It is the most abundant in the low-mountain belt in dark coniferous forests, being the dominant form of Lumbricidae there, but it is quite rare above the timberline. The range of E. n. nordenskioldi, which can be found together with E. n. pallida in the south of the territories studied, is much wider, extending further to the north and including some Arctic islands. In addition, E. n. nordenskioldi is known from the eastern parts of European Russia. Both subspecies show high levels of resistance to unfavorable abiotic factors. Differences in the latitudinal and altitudinal distribution patterns of both subspecies of E. nordenskioldi are determined by their different morpho-ecological forms.     

Host Specificity and Morphometrics of Four Populations of Heterodera glycines (Nematoda: Heteroderidae)

Four populations of Heterodera glycines from four different states differed considerably in numbers of adult females developed on five resistant soybean cultivars, mungbean and lespedeza. Differences were observed also in body, tail and tail terminus lengths of second-stage larvae. No attempt was made to assign these populations to recognized races, and it is suggested that race designations should be applied only to representative samples of field populations and not to selected greenhouse populations or isolates.     

Population dynamics of pedigree leopards,Panthera pardus ssp,in captivity

The demographic history of 4 races or subspecies of leopard, Panthera pardus, was reviewed from international studbook records dating back to 1953. The Chinese leopard has been the most common pedigree race maintained in captivity, a factor linked to the length of time (29 years) this subspecies has been in captivity. The relative youth of the wild-born founders also helped them to adjust to captivity as well as live long reproductive lives. Today, however, this race is suffering from the ill effects of inbreeding due to the small founder size. This condition appears to be correctable now that additional specimens have been located. Persian leopards have a larger founder size than the former race, but some of their ancestors were older animals at the time of acquisition. Because of this, their potential fecundity was probably depressed from psychological problems related to adjustment and a shorter life span in captivity. Two founding females experienced pelvic deformities while young, and few of their cubs survived because they all had to be delivered via caesarian section. This procedure also shortened the reproductive life of the females involved because the owning zoos refrained from breeding the animals in the leopards' later years. Captive leopards appear to live longer than their wild counterparts, although precise data on wild populations is not available. In captivity many reach 12–15 years old, and exceptional individuals of several races have lived 20 years. Most captive-born leopards begin breeding when they are 3 years old and continue until they are 8–10 years old. Reproduction in females usually ceases at 12–14 years, although males have a longer reproductive life, with several successfully breeding when 19–20 years old.     

Behavioural discrimination among chromosomal races of the house mouse (Mus musculus domesticus)

This work is concerned with the extent of behavioural discrimination between three chromosomal races of the house mouse (the standard 40-chromosome race and a 32- and 36-chromosome races) found in the vicinity of a hybrid zone in northern Scotland. Mice were investigated for several elements of their social behaviour. Within-population dyadic encounters did not show consistent behavioural differences attributable to karyotype among five populations (two standard race, two 36-chromosome race, one 32-chromosome race). Between-population dyadic encounters revealed significant differences between three populations. The standard population examined appeared to be the most “open” to foreigners, the 32-chromosome population the most “closed” while the 36-chromosome mice displayed an intermediate response. Differences in behaviour displayed during between-population as compared to within-population dyadic encounters revealed the occurrence of behavioural discrimination between populations. The implication of these results on the dynamics of the hybrid zone are discussed.     

Karyology and Oogenesis of Radopholus similis (Cobb) Thorne

Two morphologically indistinguishable races of Radopholus similis from Florida are presently identifiable only by host preference tests. One race attacks banana and other hosts, but not citrus. The other race attacks both citrus and banana, as well as other hosts. The two races normally reproduce by amphimixis. The morphology of the female reproductive systems of both races were examined and appeared to be identical. However, slight differences were observed in developmental stages of oogenesis between the two races. The two races were distinct with respect to karyotype. There were four chromosomes in the banana race and five chromosomes i n the citrus race. Karyotypic uniformity was found i n the two Florida populations of the citrus race.