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Lina Kawaguchi and Tetsukazu Yahara of the Department of Biology, Faculty of Sciences, Kyushu University along with Tomoyuki Yokoi of the Department of Environmental Ecology, Graduate School of Environmental Science, Okayama University report on the JSPS International Symposium on Pollinator Conservation—Conservation and Sustainable Use of Pollinators: Towards Global Assessments, held at Kyushu University, Fukuoka, Japan from 27th to 29th January, 2012.

To examine the evolution of gynodioecy under biparental inbreeding, we developed a new theoretical model and tested it by estimating paramaeters incorporated in the model in a gynodioecious population ofChionographis japonica var.kurohimensis. The model and the results showed biparental inbreeding affects the evolution of gynodioecy, but the effect is very small.

The number of flowers open at any one time on a plant, i.e., floral display size, varies greatly among plant species. For example, some species flower during a brief period and have many open flowers, while others have extended flowering with only a few open flowers at one time (Gentry 1974; Bawa 1983). Also, floral display size often varies among individuals of the same plant species (e.g., Willson & Price 1977; Pleasants & Zimmerman 1990). The causes of such variations in floral display size are enduring interest to plant ecologists (reviewed by de Jong et al . 1992). Numerous studies have reported that variation in floral display size produces marked alterations in pollinator behavior. Especially, two types of pollinator response to increased floral display size have been recognized from the perspective of their influences on pollen dispersal. First, larger floral displays attract more pollinators per unit of time (Fig 14.1A; reviewed by Ohashi & Yahara 1998). This will promote cross-pollination in terms of increased pollen receipt, removal, or potential mate diversity (Harder & Barrett 1996). Second, the number of flowers that individual pollinators probe per plant also increases with floral display size (Fig. 14.1B; also reviewed by Ohashi & Yahara 1998). This will increase self-pollination among flowers on the same plant (“geitonogamy”; Richards 1986; de Jong et al . 1993). Thus, variation in floral display size may lead to a substantial difference in pollen dispersal and, in turn, plant fitness.

Floral resource allocation was compared on a whole-plant basis between two varieties of Impatiens hypophylla that differ in flower size. There were significant negative correlations between flower number and investments to a flower at both the within-population and between-variety levels. In individual flowers, var. hypophylla with larger flowers invested significantly more resources to male and pollinator-attractive functions, whereas investments to female function did not differ between the varieties. In experimental populations placed in the field, pollinators preferred the larger flowers of var. hypophylla even within the same habitat of var. microhypophylla, which has smaller flowers. There was a significant lack of observed heterozygosity only in var. microhypophylla. Thus, the outcrossing variety had more attractive but fewer flowers, while the selfing variety had less attractive but more abundant flowers.

Eighteen polymerase chain reaction (PCR) products of the partial sequence of the Adh (alcohol dehydrogenase) gene from 10 Brachyscome species were sequenced and compared. These products contained the 5′ three fourths of exon 4 and whole sequences of intron 3. They varied extensively in length due to the differences in length of intron 3. A total of 10 long insertions were flanked by direct repeats of 5 to 12 bp sequences, indicating inserted elements. These inserted elements were classified into the following five categories based on nucleotide sequence characteristics and length; (1) a region homologous to that of 5S RNA genes (5S DNA), (2) A-rich structure at the 3′ end-like short interspersed elements (SINEs) in animals, (3) a sequence of 280 bp with no characteristic features, (4) a sequence of 125 bp with no characteristic features, (5) termini of 11 bp inverted repeats flanked by 5 bp sequence of direct repeats characteristics of a transposon.

The daylily (Hemerocallis fulva) and nightlily (H. citrina) are typical examples of a butterfly-pollination system and a hawkmoth-pollination system, respectively. H. fulva has diurnal, reddish or orange-colored flowers and is mainly pollinated by diurnal swallowtail butterflies. H. citrina has nocturnal, yellowish flowers with a sweet fragrance and is pollinated by nocturnal hawkmoths. We evaluated the relative roles of flower color and scent on the evolutionary shift from a diurnally flowering ancestor to H. citrina. We conducted a series of experiments that mimic situations in which mutants differing in either flower color, floral scent or both appeared in a diurnally flowering population. An experimental array of 6 × 6 potted plants, mixed with 24 plants of H. fulva and 12 plants of either F1 or F2 hybrids, were placed in the field, and visitations of swallowtail butterflies and nocturnal hawkmoths were recorded with camcorders. Swallowtail butterflies preferentially visited reddish or orange-colored flowers and hawkmoths preferentially visited yellowish flowers. Neither swallowtail butterflies nor nocturnal hawkmoths showed significant preferences for overall scent emission. Our results suggest that mutations in flower color would be more relevant to the adaptive shift from a diurnally flowering ancestor to H. citrina than that in floral scent.

It is impractical to avoid all kinds of ecological risk. Risk assessment is becoming common in a wide range of natural and social sciences, but the extinction risk of threatened species is usually based on inadequately known factors. We should develop a conservation program for threatened species as soon as possible, even though we need much more time to investigate the extinction risks of these species. Uncertainty is a significant aspect of environmental problems, global warming, the effect of endocrinedisrupting chemicals, and ecosystem management. Risk is a probability, based on some uncertainties. IUCN (the World Conservation Union) determmed five quantitative criteria for classification within the threatened categories (IUCN 1994). Among these, criterion E directly refers to extinction probability. However, it is difficult to apply this criterion to data-poor situations. For most of the threatened species that are not commercially exploited, we rarely know the population size. Therefore, IUCN’s criterion A is solely based on the population decline rate, no matter how large the population size. This criterion is applied to any species, including commercially exploited marine species, despite the fact that extinction risk depends on the rate of decline, its variation, and the absolute size of

Pathogenic DNA paints summer foliage gold, and inspired a poet over a millennium ago. The Man'yoshu, meaning 'collection of ten thousand leaves', is the largest and earliest anthology of Japanese poetry — it contains over 4,500 poems written between the early seventh century and the middle of the eighth century, and provides a glimpse of Japanese life during that period. One poem, attributed to the Empress Koken and written in the summer of 752 ad (Fig. 1), describes the autumnal appearance of eupatorium plants in summer1 and is reputedly the earliest written record of the symptoms of a plant virus disease2. Here we show that a geminivirus and an accompanying satellite component isolated from affected eupatorium plants are together responsible for the spectacular foliar display that was first noted by the Empress more than a millennium ago.

Variation in the number of flowers open at any one time on a plant or an inflorescence, i.e. floral display size, is probably the major factor that affects pollen flow and plant fitness through behavioral responses of pollinators on plants. Many authors have reported that pollinators visit large floral displays more frequently than small ones (e.g. Heinrich 1979, Ohara and Higashi 1994), whilst also visiting more flowers on larger displays (e.g. Geber 1985, Harder and Barrett 1995). With regard to these two types of pollinator response to increased display size, it has often been explained that pollinators visit large floral displays more frequently as a consequence of the associated lower flight costs per flower (Harder and Cruzan 1990, Robertson and Macnair 1995). However, it seems that pollinators do not always behave in a way that will minimize flight costs per flower. Rather, it has often been observed that a smaller proportion of open flowers was probed on larger displays (Pleasants and Zimmerman 1990 and references therein). This fact seems to contradict the above explanation. Why do pollinators visit a smaller fraction of open flowers during their visit to a large floral display? And if they do, then why should they visit larger displays more frequently than smaller ones? In this article, we propose a new idea for answering these questions by exploring theoretically how foraging patterns of pollinators may depend on floral display size, from the perspective of pollinators' optimal foraging. We then test whether observed patterns in the literature support the predictions of our model.

Time of flower opening (anthesis) is one of the floral traits comprising a pollination syndrome. The time when pollinators are active has been thought to exert selective pressures on anthesis, but no models have been developed to explain it. Using a simulation model, we estimated the number of pollen grains transferred by both diurnal and nocturnal pollinators in flowers opened at dusk, midnight, morning, and noon. We assumed that pollen removal is proportional to the amount of pollen in the flower and that poller: deposition is an increasing and decelerating function of pollen removal. Pollen removal efficiencies and pollen deposition efficiencies of nocturnal and diurnal pollinators were estimated from field data for Lonicera japonica. Anthesis at dusk was favored, even with a larger number of diurnal pollinators, up to ten, versus two nocturnal pollinators. As long as both the pollen removal efficiency of nocturnal pollinators was lower and their pollen deposition efficiency was higher than those of diurnal pollinators. anthesis at dusk was favored, even when diurnal pollinators transferred more pollen than nocturnal ones. Anthesis at dusk may not be a specialization for nocturnal pollinators.

An electrophoretic study of isozyme number for seven soluble enzymes revealed extensive gene duplications in eight diploid species of American Eupatorium belonging to three morphological groups. The enzymes isocitrate dehydrogenase, phosphoglucomutase, phosphoglucose isomerase, 6-phosphogluconate dehydrogenase, and shikimate dehydrogenase occur as three to six isozymes in all species, whereas the minimal conserved number typical of diploid plants is two isozymes for each. Fructose 1, 6-biphosphate aldolase is expressed as multibanded pattern suggesting fixed heterozygosity in all examined species. It was not possible to document gene duplication for triosephosphate isomerase from the electrophoretic patterns. All species examined have a chromosome number of 2n = 20, which has been regarded as the basic diploid number for Eupatorium. However, the detection of extensive duplications suggests that 2n = 10 may be the original diploid chromosome number in Eupatorium and that plants with 2n = 20 are of polyploid origin. This hypothesis would mean that extensive duplications at isozyme gene loci have been maintained since the origin of the genus, despite chromosomal diploidization having occurred. IT HAS BEEN documented that diploid vascular plants have a minimal highly conserved number of isozymes for most of the enzymes routinely examined by electrophoresis (Gottlieb, 1981 a, 1982, 1983, 1984). This means that an increase in isozyme number for a given enzyme is the result either of gene duplication at the diploid level or of polyploidy. If a plant is polyploid, then it should have duplications at many isozyme loci, whereas a diploid plant would exhibit much less extensive increase in isozymenumber(Gottlieb, 1981a, 1983,1984). While inferences about whether given plants are diploids or polyploids have often rested primarily on their chromosome numbers, Gottlieb (1981b) employed isozyme number to infer the ploidy level of plants when chromosome data per se were inconclusive. Gottlieb (198 lb) argued that an essential feature of polyploid is the number of genomes being expressed, and that chromosome number alone

Peroxidase phenotypes of two all-agamospermous “species” of Eupatorium in the southeastern United States were examined. The result supported a hybrid origin (E. recurvans × E. rotundifolium) for E. scabidum and an autopolyploid origin from E. recurvans for E. mohrii. Notable variations of E. scabridum in its leaf morphology and peroxidase phenotype were suggestive of occasional sexuality in this agamospermous “species”.

Examinations of chromosome number voucher specimens show that sexual diploid and agamospermous polyploid plants of Eupatorium in Asia can be distinguished by morphology, fertility, and stainability of pollen grains. Using these criteria, reproductive systems (sexual vs. agamospermous) were estimated for 558 herbarium specimens of Eupatorium in East Asia. Of 22 taxa examined, six included both sexual and agamospermous specimens; those of one taxon were all agamospermous; and those of 15 taxa were all sexual. This result shows that 21 taxa are not agamospermous microspecies but are differentiated at the diploid level. Sexual populations of most taxa had restricted geographical distributions. Eupatorium chinense var. chinense and var. oppositifolium consisted of both sexual and agamospermous populations. Sexual populations of these two varieties were allopatric and distinct in external morphology, suggesting differentiation at the species level. The specimens of E. heterophyllum s. str. were all agamospermous, while those of E. mairel, often treated as synonymous with E. heterophyllum, were sexual. In comparing East Asian and North American Eupatorium for the distributional patterns of sexual and agamospermous populations, three differences can be pointed out: (1) Agamospermous plants of autopolyploid origin have evolved in eight species and are widespread in North America; while most agamospermous plants in East Asia may be of allopolyploid origin, have relatively restricted ranges, and are less frequent than the diploid plants with the exception of in E. chinense var. oppositifolium, (2) The number of sexual species with wide range is greater in North America than in East Asia. (3) The number of sexual species with restricted ranges is greater in East Asia than in North America. The results obtained suggest that speciation among the plants of Eupatorium has occurred more recently in East Asia than in North America.

The frequency of hybrids was monitored using progenies grown from seeds collected from open-pollinated plants in mixed populations of Farfugium hiberniflorium and F. japonicum. The results showed that hybrids are more frequently derived from F. japonicum than from F. hiberniflorum. This directionality of hybridization and extraordinarily high frequency of hybrids among progenies grown from seeds from open-pollinated plants of F. japonicum enabled us to derive an empirical equation describing the frequency of hybridization as a decreasing exponential function of interspecific plant distance. The relationship between these two variables fitted a function describing pollen flow from a particular plant. This finding suggests that interspecific pollen exchange can be viewed simply as a process dependent of interspecific plant distance, and the actual rate of hybridization is determined by the level of cross-compatibility of a particular species.

The examination of 1976 herbarium specimens ofEupatorium chinense subsp.sachalinense var.oppositifolium and 908 of var.sachalinense revealed their distinct geographical and ecologial distribution patterns. Var.oppositifolium includes two distinct groups: the diploid type and the polyploid one. The distribution of the diploid type is restricted to the “Sohayaki-Region”, and its habitat appears to be restricted to fragile gravitational slopes and rocky areas which lack tall competitors. In contrast, the polypoid type is widely distributed throughout the Japan Archipelago. The polyploids grow successfully in recently cleared dry habitats and in repeatedly disturbed tall grass and forb communities. Climatic warming after the last-glaciation combined with explosive agricultural developments and the polyploids rapid and tall growth habits with agamospermous reproduction seem to have facilitated their northward migration and distributional expansion. Karyotype analyses were made on 29 populations of var.oppositifolium which comprised eight cytotypes: 2x, 3x, 4x, 5x based on x=10, 3 chromosomally deficient polyploids and an aneuploid with 2n=39. Most populations exhibited various combinations of polyploid cytotypes. Different polyploid cytotypes show no apparent habitat preferences. None of the polyploid cytotypes appear to compete with each other in colonizing and exploiting newly disturbed habitats. This, together with their agamospermous propagation, rare sexuality and random association when colonizing, can result in an intricate mixture of various cytotypes within local populations.

The taxonomic status ofEupatorium chinese var.oppositofolium andE. glehni (=E. chinense subsp.sachalinense) inE. chinense complex semsu Kitamura has long been controversial. In this paper, the degree of divergence between diploids of these two taxa was examined by means of morphological studies including principal component analysis, the electrophoretic analysis of esterase isozyme variation and observations on habitats. The data obtained through the examinations indicate these two taxa are diverged enough to be recognized as distinct biological species. Since the polyploidE. chinense var.oppositifolium is more or less intermediate in morphology between the two diploid taxa, it is considered to have masked the distinction between the two diploid taxa. Also, electrophoretic evidence suggests that polyploidE. chinense var.oppositifolium is not a hybrid or hybrid derivative withE. glehni as a parental species. Possible origin of polyploidE. chinense varoppositifolium is also discussed.

Observations in two populations of Asarum caulescens belonging to sect. Asarum indicate that inbreeding predominates becuase (1) no effective pollinator was observed, (2) bagged flowers set fruits with well-swollen seeds, and (3) the behaviour of filaments, changing from recurved to straight posture, results in direct deposition of pollen grains on the stigmas. This result agrees with reports on three other species of sect. Asarum in Europe and North America. We suggest that species of sect. Asarum diverged from an autogamous ancestor.

The Global Legume Diversity Assessment (GLDA) proposes the legume family (Fabaceae or Leguminosae) – one of the largest and economically important plant families – as a target for a global botanical diversity assessment project. Where in the Neotropics and Africa legumes dominate the rain forest in terms of diversity and abundance, the Dipterocarpaceae claim this role in South East Asia and on Sundaland in particular. This raises the question whether legumes are an indicator for overall botanical diversity on Sundaland? To answer this question we use the largest compiled database of collection records of the region and species distribution modelling techniques. As a proxy for total botanical diversity we selected seven plant families; Dipterocarpaceae, Ericaceae, Fagaceae, Lauraceae, Moraceae, Myristicaceae, and Sapindaceae. Although the legumes were the most diverse family, the predictive power of legume diversity for overall botanical diversity was poor. This related to the fact that the other seven selected families largely represent trees, whereas legume species more equally represent all different growth forms. After assigning individual legume species to different growth habits (tree, liana, herb, miscellaneous) we were able to predict 78% of the variance in botanical diversity on Sundaland. The lianas represent the single growth habit that best predicted (66%) the variance in botanical diversity. The herb- and miscellaneous growth habits had an inverse relationship to botanical diversity. Legumes can be used as a predictor of overall botanical diversity in tropical and seasonal rain forests, but the relationship should be fitted for different biogeographic regions individually.

(x=17 and 25), Ageratina (x=17) and Sclerolepis (x=15) with the higher chromosome base numbers, and the other includes Mikania (x=17) and the remaining genera with lower chromosome base numbers (x=10–11). However, the monophyly of the former clade is supported with a low bootstrap value. In the latter clade, Mikania (x=17) diverged first, then Stevia (x=11), and finally eight genera with x=10 diverged in succession. This result supports the hypothesis that the genera in the tribe Eupatorieae with x =10 evolved from an ancestor with a higher base number, and the tribe is of polyploid origin.

Researchers have often assumed that the reproductive success of a plant increases with flower production. However, if predispersal seed predation also increases with flower production, this may counteract the increase in reproductive success expected with such increased flower production. To investigate this, we examined the effect of flower number and predispersal seed predation on seed production in two field populations of Cirsium purpuratum (Maxim.) Matsum. At both sites, the proportion of seeds or heads preyed upon per plant increased with the number of flowers (florets or heads) on each plant, while the proportion of mature seeds per plant was independent of flower number per plant. Based on these results, we predicted that an increased level of seed predation at the population level would reduce the annual flower production of each plant. The observed pattern of flower production supported this prediction. Our results suggest that increased flower production may not always improve plant reproductive success under the influence of predispersal seed predation.Key words: plant reprodutive success, predispersal seed predation, Cirsium purpuratum, flower production, plant-animal interaction.

Few studies have been made on the molecular divergence of plant viruses. To remedy this deficiency, we examined the molecular divergence of the tobacco leaf curl geminivirus (TLCV). TLCV infects not only tobacco but alsoEupatorium andLonicera in the field and causes yellow vein disease. A total of 29 nucleotide sequences of the replication protein gene (ORF C1) of geminiviruses infecting wild plants ofE. makinoi, E. glehni andL. japonica collected from ten localities was determined. Highly divergent sequences were obtained not only among host plant populations but also within a host population. Phylogenetic analyses showed that the TLCVs infectingEupatorium andLonicera were clustered into three different clades, and were either paraphyletic or polyphyletic. This result is the first evidence demonstrating that wild populations of single plant species possess genetically diversified virus strains. Comparison with recently reported genetic variations of tobacco mild green mosaic tobamovirus (TMGMV) revealed three characteristics of TLCV evolution: (1) a higher nucleotide substitution rate, (2) more frequent migration among geographically isolated host populations, and (3) more frequent host changes to different plant families. While TMGMV is an RNA virus, TLCV has DNA genomes. In animal viruses, RNA viruses tend to evolve faster than DNA viruses. Our results indicated that this trend may not hold for plant viruses.