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Adaptive introgression plays a vital role in allowing recipient species to adapt and colonize new environments. However, our understanding of such environment-dependent introgressions is primarily limited to specific plant taxa in particular settings. In Japan, two related orchid species, the autonomously self-pollinating Pogonia minor and the outcrossing Pogonia japonica , typically inhabit dry grasslands and wetlands, respectively. Intriguingly, an island ecotype of P. japonica exists in arid, wind-swept, open sites on volcanic mountain slopes on Kozu Island, in the oceanic Izu Islands. To investigate potential introgression and its implications between P. japonica and P. minor on Kozu Island, we applied a comprehensive approach that included examining morphological traits, genome-wide SNP data, and plastid DNA sequences. We also examined the breeding systems of these species on Kozu Island through artificial pollination experiments to determine if introgression from P. minor has endowed the P. japonica ecotype with selfing capabilities. Extensive sampling on Kozu Island revealed that all P. japonica specimens exhibit signs of introgression from P. minor , suggesting the absence of pure P. japonica populations on the island. Furthermore, the chloroplast haplotypes of the insular P. japonica ecotype consistently match those of P. minor , indicating a predominantly asymmetrical initial hybridization with P. minor acting mainly as the maternal parent in the formation of F1 hybrids. Despite the advantages of self-fertilization in isolated environments, the insular P. japonica does not exhibit autogamy. Consequently, the scarcity of moist habitats, rather than selection pressure for selfing, likely contributes to the observed widespread introgression. Our study strongly suggests that the arid-environment-adapted P. minor has introgressed into the insular ecotype of P. japonica , enabling its successful colonization of arid volcanic mountain slopes of the oceanic island. [ABSTRACT FROM AUTHOR]

Insular animals are thought to be under weak predation pressure and increased intraspecific competition compared with those on the mainland. Thus, insular populations are predicted to evolve 'slow' life histories characterized by fewer and smaller clutches of larger eggs, a pattern called the 'island syndrome'. To test this pattern, we collected data on egg volume, clutch size and laying frequency of 31 Aegean Island populations of the closely related geckos of the Mediodactylus kotschyi species complex. We tested how predation pressure, resource abundance, island area and isolation influenced reproductive traits. Isolation and predation were the main drivers of variation in life-history traits. Higher predator richness seemed to promote faster life histories, perhaps owing to predation on adults, whereas the presence of boas promoted slower life histories, perhaps owing to release from predation by rats on the eggs of geckos. Insular geckos followed only some of the predictions of the 'island syndrome'. Predation pressure seemed to be more complex than expected and drove life histories of species in two opposing directions. Our results highlight the importance of considering the identity of specific predators in ecological studies. [ABSTRACT FROM AUTHOR]

Many theoretical studies have suggested that disruptive selection plays an important role in phenotypic divergence, but few studies have determined the action of disruptive selection on phenotypic divergence via field studies. This study investigated the effect of disruptive selection on shell colour polymorphism in the Japanese land snail Euhadra peliomphala simodae to determine whether extreme phenotypes of snail shell colour are favoured over intermediate phenotypes. We conducted field surveys on an oceanic island with black, yellow and intermediate-coloured E. p. simodae snails. We captured and marked ~1800 individual snails and monitored their survival over 18 months. We quantified shell colours against images and examined the frequency distribution of shell colour variation. The variation exhibited a bimodal distribution with a far lower frequency of intermediate-coloured snails than of black or yellow snails. The population sizes of the three snail groups fluctuated synchronously with the changing seasons. Bayesian estimates showed lower survival rates for juvenile intermediate-coloured snails than for juvenile black and yellow snails, implying there was disruptive selection associated with shell colour. We suggest this disruptive selection may have resulted in the evolutionary divergence of the snail's shell colour within the lineage having high shell colour variation. [ABSTRACT FROM AUTHOR]

In the Cabo Verde archipelago, Campanula spp. (bellflowers) are currently represented by four endemic species restricted to mountainous islands (C. bravensis , C. feijoana , C. hortelensis and C. jacobaea), all of which are known for high floral polymorphism. Diagnostic features of the corolla often differ from original descriptions, bringing into question their taxonomic delimitation. Based on the variations in the corolla shape observed during fieldwork, eight morphogeographical entities were distinguished among the taxa in the archipelago. Geometric morphometrics was used to quantify and examine these floral variations. Corolla morphology of 221 photographed flowers was captured by 2D landmarks and semi-landmarks configurations and analysed with canonical variate analysis. The results show agreement between morphological groupings and their geographical ranges. For most entities, the geographical origin may be determined with accurate morphological examination of the flower. In this case, the corolla shape proves to be a taxonomically discriminant trait. Furthermore, the terminology used until now to characterize these different floral forms is discussed. The present study contributes significantly to clarifying the floral polymorphism in Cabo Verdean Campanula and suggests that taxonomic revision of this group is necessary. [ABSTRACT FROM AUTHOR]

Natural hybridization often occurs between insular and widespread species, and investigating these hybridization patterns is important in improving our understanding of the evolution of insular plant species. To this end, we studied the floral morphology and genetic structure of the widespread species Calanthe discolor , the insular closely related species C. izu-insularis and their putative natural hybrids on Honshu Island (mainland) and the Izu Islands (oceanic islands), Japan, using microsatellite markers. Natural hybridization probably occurred on all the investigated Izu Islands in Japan, although C. izu-insularis was morphologically and genetically different from C. discolor. Bumblebees and other relatively large bees are not distributed in the Izu Islands and therefore natural hybridization would have occurred via pollination by relatively small solitary bees that are pollinators of both Calanthe spp. We also showed that in the islands more remote from the mainland, the proportions of insular C. izu-insularis increased and the floral morphologies of both species changed. The results suggested that insular C. izu-insularis evolved on the Izu Islands and the widespread C. discolor adapted to the poor pollinator fauna on oceanic islands. [ABSTRACT FROM AUTHOR]

DNA barcoding has been largely successful in differentiating animal species, but the most effective loci and evaluative methods for plants are still debated. Floras of young, oceanic islands are a challenging test of DNA barcodes, because of rapid speciation, high incidence of hybridization and polyploidy. We used character-based, tree-based and genetic distance-based methods to test DNA barcoding of 385 species of native Hawaiian plants constituting 20 lineages at the nuclear ITS(2) locus, nine lineages at each of the plastid loci trnH-psbA and rbcL , eight lineages at the plastid locus matK and four lineages with concatenated data. We also incorporated geographical range information and tested if varying sample sizes within a lineage influenced identification success. Average discrimination success was low (22% maximum) with all methods of analysis across all loci. The character-based method generally provided the highest identification success, there were limited benefits from incorporating geographical data and no relationship between number of species sampled in a lineage and identification success was found. Percentages of identification success are the lowest reported in a DNA barcoding study of comparable scale, and multi-species groups that radiated in the Hawaiian archipelago probably cannot be identified based on current DNA barcoding loci and methodologies. [ABSTRACT FROM AUTHOR]

Recent revision of the fern diversity of the French Caribbean island of Guadeloupe and its dependencies (Marie Galante, Les Saintes and La Désirade) resulted in the listing of 292 native ferns and club mosses in 28 families and 88 genera, of which eight ferns are endemic to Guadeloupe and 20 taxa are only recorded from the Lesser Antilles. Additionally, 21 species have recently been found to be naturalized. Nineteen new combinations are made and a new hybrid is described. Many types from the Fée collection have been reassessed and a number of names are lecto- or neotypified. Studied specimens are cited and localities are provided. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 161, 213–277. [ABSTRACT FROM AUTHOR]

Ipomoea habeliana is an endemic, night-flowering member of the Galápagos flora. Pollination experiments, flower-visitor observations, nectar sampling, pollen transfer, and pollen to ovule ratio and pollen size studies were included in this project. The large, white flowers of this species set fruit via open pollination (55%), autonomous autogamy (51%), facilitated autogamy (91%), cross-pollination (80%), diurnal open pollination (60%) and nocturnal open pollination (60%). Fruit set is pollen-limited. Ants, beetles, crickets and hawk moths regularly visit the flowers. Ants are the most frequent visitors, but hawk moths are the only effective pollinators. Nectar is available throughout the night, but is most abundant early in the evening when hawk moth visits are most frequent. Experiments with fluorescent dust demonstrate intra- and inter-plant pollen movement by hawk moths. Although this species is adapted for hawk moth pollination, it readily sets fruit via autonomous autogamy when no visits are made. Thus, it is concluded that it is facultatively xenogamous. Additional support for this conclusion is provided by the pollen to ovule ratio of 1407 and by the fact that the plants grow in a region that has few or no faithful pollinators. Conservation efforts for I. habeliana should include hand pollinations, which could significantly increase seed set. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 160, 11–20. [ABSTRACT FROM AUTHOR]

Tournefortia rufo-sericea is an endemic member of the Galápagos angiosperm flora. Although not uncommon within the archipelago, its status is presently listed as vulnerable and, as such, a complete knowledge of its pollination biology may prove useful in preventing its decline. Pollination experiments, flower-visitor observations, nectar and fluorescence studies, as well as pollen : ovule ratio and pollen size studies were included in this investigation. The small, white flowers of this species set fruit via open pollination (81%), autonomous self-pollination (80%), diurnal pollination (80%), and nocturnal pollination (85%). Ants are the most common visitor to the flowers of this species, primarily during the day, whereas beetles and moths make visits at night. A small amount of nectar is presumably produced, as moths are often seen probing the corollas. Experiments with fluorescent dust did not support interflower pollen movement. The pollen : ovule ratio was 4972 : 1, which suggests xenogamy, and the mean pollen size was 21 µm. Despite the pollen : ovule ratio, it appears that this species exhibits a breeding strategy of facultative autogamy, in which the majority of flowers set fruit via autonomous self-pollination, but limited outcrossing may occur when pollinators are available. Conservation efforts for T. rufo-sericea should focus on the control or eradication of exotic species. © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society, 2007, 153, 21–31. [ABSTRACT FROM AUTHOR]

Most moths use ears solely to detect the echolocation calls of hunting, insectivorous bats and evoke evasive flight manoeuvres. This singularity of purpose predicts that this sensoribehavioural network will regress if the selective force that originally maintained it is removed. We tested this with noctuid moths from the islands of Tahiti and Moorea, sites where bats have never existed and where an earlier study demonstrated that the ears of endemic species resemble those of adventives although partially reduced in sensitivity. To determine if these moths still express the anti-bat defensive behaviour of acoustic startle response (ASR) we compared the nocturnal flight times of six endemic to six adventive species in the presence and absence of artificial bat echolocation sounds. Whereas all of the adventive species reduced their flight times when exposed to ultrasound, only one of the six endemic species did so. These differences were significant when tested using a phylogenetically based pairwise comparison and when comparing effect sizes. We conclude that the absence of bats in this habitat has caused the neural circuitry that normally controls the ASR behaviour in bat-exposed moths to become decoupled from the functionally vestigial ears of endemic Tahitian moths. [ABSTRACT FROM AUTHOR]