Morphological,molecular and biological evidence reveal two cryptic species in Mecinus janthinus Germar (Coleoptera,Curculionidae), a successful biological control agent of Dalmatian toadflax,Linaria dalmatica (Lamiales,Plantaginaceae)

A combined morphological, molecular and biological study shows that the weevil species presently named Mecinus janthinus is actually composed of two different cryptic species: M. janthinus Germar, 1821 and M. janthiniformis To?evski & Caldara sp.n. These species are morphologically distinguishable from each other by a few very subtle morphological characters. On the contrary, they are more readily distinguishable by both molecular and biological characters. A molecular assessment based on the mitochondrial DNA cytochrome oxidase subunit II gene revealed fixed differences between the two species with p‐distances between samples of both species ranging from 1.3 to 2.4%. In addition to this, the larvae of the two species are found to develop on different species within the genus Linaria (Plantaginaceae): M. janthinus is associated with yellow toadflax (L. vulgaris) and M. janthiniformis with broomleaf toadflax (L. genistifolia) and Dalmatian toadflax (L. dalmatica). Molecular and host use records further suggest the occurrence of a third species associated with L. vulgaris within M. janthinus, sampled from north Switzerland, central Hungary and east Serbia. The significance of these new findings is of particular importance because species of the M. janthinus group are used, or are potential candidates, for the biological control of invasive toadflaxes in North America.     

A new subspecies of <Emphasis Type="Italic">Centaurea cassia</Emphasis> (Asteraceae) from Turkey

A new subspecies in sect. Jacea (Mill.) DC., Centaurea cassia Boiss. subsp. dumanii M. Dinç, A. Duran &; B. Bilgili subsp. nov., collected by the authors from South Anatolia, is described and illustrated. The new subspecies is restricted to Abies cilicica (Ant. &; Kotschy) Carr. subsp. cilicica forest above Göller Yaylas? (C6 Adana-Kozan). Diagnostic morphological characters from C. cassia subsp. cassia are discussed. The ecology, biogeography and conservation status of the new taxon are also presented.     

Astragalus raphaelis (Fabaceae), a critical species from Sicily and taxonomic remarks on A. sect. Sesamei

The taxonomic position of Astragalus raphaelis, a rare and misappreciated species endemic to Sicily, has been examined. In addition, its geographical distribution, ecology and conservation status, diagnostic morphological characters, pod and seed micro‐morphology and relationship with A. stella are provided. Phenetic and phylogenetic trees (based on morphological data) for A. sect Sesamei shows that A. raphaelis is a taxonomically quite isolated species, with some relationships to A. sesamoides.     

Germination behaviour of 14 Mediterranean species in relation to fire factors: smoke and heat

Fire is an ecological factor that has been present in the ecosystems of the Mediterranean region for thousands of years. Our study was undertaken to acquire knowledge of the effect of fire on the germination of Mediterranean species. We used high temperatures (up to 60°C) and smoke to determine the effect of these factors on the germination of species from the Mediterranean region. The species selected are characteristic of the central Mediterranean basin and are representative of both woody and herbaceous species: Rhamnus alaternus L., Cistus albidus L., Cistus monspeliensis L., Fumana ericoides (Cav.) Gand., Rosmarinus officinalis L., Melica ciliata L., Avena sterilis L., Bituminaria bituminosa (L.) C.H. Stirt., Anthyllis vulneraria L., Coronilla glauca L., Argyrolobium zanonii (Turra) P.W. Balland, Emerus major Mill., Genista scorpius (L.) D.C. and Spartium junceum L. The seeds were collected in Mediterranean shrubland (8) and woodland (6) ecosystems, around Montpellier, France (24°45′N and 3°50′E). Ten treatments were tested: a control, three smoke treatments and six heat treatments. The average germination level (germination percentage) and the average T₅₀ rates (time taken to reach 50% of germination) were calculated. The smoke and heat act in a different way on each of the species. The smoke enhanced the germination of two species, whilst moderate heat increased germination in all of the species excepting R. officinalis, F. ericoides, A. sterilis, A. vulneraria, and G. scorpius. Germination was fastest in M. ciliata and S. junceum and slowest in A. sterilis, E. major and C. albidus. The cues did not significantly affect the rate of germination. Fire modified the germination response of 12 of the 14 species studied.     

Host-plant preference of Brachypterolus pulicarius, an inadvertently introduced biological control insect of toadflaxes

Brachypterolus pulicarius (L.) (Coleoptera: Kateridae) is an inadvertently introduced biological control agent that can reduce seed set in two North American invasive species, yellow (Linaria vulgaris P. Mill.) (Scrophulariaceae) and Dalmatian toadflax (Linaria genistifolia (L.) P. Mill. ssp. dalmatica). The beetles are more common on yellow toadflax than on Dalmatian toadflax. To understand their distribution on the two host plants, we investigated whether they prefer one host to the other and whether individuals aggregate toward conspecifics. In field and laboratory experiments where beetles were presented with a choice of both toadflax species, B. pulicarius sampled from both host plants preferred yellow toadflax. However, in the laboratory experiment, beetles collected from Dalmatian toadflax showed a weaker preference for yellow toadflax than beetles collected from yellow toadflax. In the field experiment, all beetle populations sampled showed similar preferences. When given a choice between yellow toadflax plants with and without trapped adult B. pulicarius, beetles preferred plants with conspecifics, suggesting aggregation toward beetle pheromones or host‐plant volatiles induced by beetle activity. These results do not support the current practice of redistributing North American B. pulicarius onto Dalmatian toadflax because of their preference for yellow toadflax.     

Ecophysiological responses of six coastal dune species along the eastern seaboard of South Africa

Ecophysiological responses of six co‐occurring dune species were investigated in a field study to determine whether they exhibit similar functional traits in response to environmental stressors. The species included Brachylaena discolor DC, Chrysanthemoides monilifera (L.), Scaevola plumieri (L.) Vahl, Canavalia maritima (Aubl.) Thouars, Gazania rigens (L.) Gaertn. and Cyperus esculentis L. Carbon dioxide exchange was saturated at 1,800 μmol m^?2 s^?1 in S. plumieri and at 1,000–1,300 μmol m^?2 s^?1 in the others. Maximal CO₂ exchange occurred during mid‐morning. Midday stomatal closure occurred in S. plumieri, C. monilifera and B. discolor, while stomatal regulation was achieved by maintaining low conductance. Photoinhibition was minimized by efficient mechanisms for light dissipation. Species such as S. plumieri, C. maritima and B. discolor exhibited sclerophylly, a trait for survival in saline and nutrient‐ and water‐deficient environments. Concentrations of Na⁺ and Cl^?1 were high in C. monilifera, G. rigens, B. discolor and S. plumieri, while the high C:N ratio in S. plumieri and C. esculentis suggested nitrogen deficiency. The responses of the six species to environmental stressors in terms of light use, gas exchange, ion and water relations and degree of sclerophylly suggest similar strategies for survival in the dune environment.     

Molecular phylogeny reveals the existence of two sibling species in the aphid pest Brachycaudus helichrysi (Hemiptera: Aphididae)

Piffaretti, J., Vanlerberghe‐Masutti, F., Tayeh, A., Clamens, A.‐L., C?ur d’Acier, A. & Jousselin E. (2012). Molecular phylogeny reveals the existence of two sibling species in the aphid pest Brachycaudus helichrysi (Hemiptera: Aphididae). —Zoologica Scripta, 41, 266–280. Brachycaudus helichrysi is a worldwide polyphagous aphid pest that seriously damages its primary hosts (Prunus spp.) and the various cultivated plants among its secondary hosts (e.g. sunflower). A recent study of the Brachycaudus genus suggested that this species might encompass two differentiated lineages. We tested this hypothesis, by carrying out a phylogenetic study of this aphid pest based on worldwide sampling and the evaluation of mitochondrial, nuclear and Buchnera aphidicola DNA markers. We show that this species is actually an amalgamation of two sibling taxa, B. helichrysi H1 and B. helichrysi H2, that seem to have overlapping geographic ranges and herbaceous host plant preferences. These two taxa displayed levels of genetic divergence as great as those generally found between sister species in the Brachycaudus genus, suggesting that they actually correspond to two distinct species. Our phylogenetic reconstructions revealed a degree of incongruence between the topologies obtained with the aphid gene data set and with data for a DNA marker from its primary endosymbiont. We identified possible reasons for this observation and discuss the ecological and genotypic data suggesting that B. helichrysi H1 and B. helichrysi H2 have different life cycles.     

Mycorrhizal species identity affects plant community structure and invasion: a microcosm study

Previous studies have shown that arbuscular mycorrhizal fungi (AMF) can mediate plant interactions, thereby affecting plant community structure. Little is known, however, about whether the presence of different AMF species leads to differences in plant community structure or invasion success by introduced species. To investigate the effects of AMF species on community structure and invasion, we created replicate microcosms containing soil inoculated with one of three different AMF species (Glomus spurcum Pfeiffer, Walker & Bloss, Scutellospora erythropa (Koske & Walker) Walker & Sanders, or Scutellospora verrucosa (Koske & Walker) Walker & Sanders) or a mixture of all three AMF species. Seeds of seven naturally co‐occurring plant species (Ageratum conyzoides L., Cyperus compressus L., Chamaecrista nictitans (L.), Crotalaria incana L., Hyptis pectinata (L.) Poit., Sida rhombifolia L., Melinis repens (Willd.) Zizka) in Hawai‘i were sown equally into these microcosms, which were placed on outdoor benches. Plant community development was monitored over a season. Mid‐way through the experiment, an invader (Bidens pilosa L.) was added to the established communities to determine whether mycorrhizal species identity affected invasion success. Final aboveground and belowground phytomass were used to assess plant community differences among treatments. Although the identity of the dominant plant species (Melinis repens) remained the same in all treatments, community dominance, community productivity, plant species richness, Shannon index of diversity, and invasion success all varied with AMF species identity. Invasion success was not inversely related to species richness or diversity. Instead, increased richness, diversity, and invasion success all appeared to be related to decreased dominance by M. repens in the presence of certain AMF species. These results indicate that the composition of the AMF community belowground can influence the structure of the plant community aboveground, and may play a role in facilitating or repelling invasion.     

Twenty‐five years after: post‐introduction association of Mecinus janthinus s.l. with invasive host toadflaxes Linaria vulgaris and Linaria dalmatica in North America

Linaria vulgaris, common or yellow toadflax, and Linaria dalmatica, Dalmatian toadflax (Plantaginaceae), are Eurasian perennial forbs invasive throughout temperate North America. These Linaria species have been the targets of classical biological control programmes in Canada and the USA since the 1960s. The first effective toadflax biological control agent, the stem‐mining weevil Mecinus janthinus (Coleoptera: Curculionidae) was introduced from Europe in the 1990s. This weevil has become established on L. dalmatica and L. vulgaris in both countries, although it has shown greater success in controlling the former toadflax species. Genetic and ecological studies of native range M. janthinus populations revealed that weevils previously identified as a single species in fact include two cryptic species, now recognised as M. janthinus, associated with yellow toadflax, and the recently confirmed species Mecinus janthiniformis, associated with Dalmatian toadflax. The results of a comprehensive study characterising haplotype identities, distributions and frequencies within M. janthinus s.l. native range source populations were compared to those populations currently established in the USA and Canada. The presence of both Mecinus species in North America was confirmed, and revealed with a few exceptions a high and consistent level of host fidelity throughout the adopted and native ranges. Genetic analysis based on mitochondrial cytochrome oxidase subunit II gene (mtCOII) defined the origin and records the subsequent North American establishment, by haplotype, of the European founder populations of M. janthinus (northern Switzerland and southern Germany) and M. janthiniformis (southern Macedonia), and provided population genetic indices for the studied populations. This analysis together with existing North American shipment receipt, release and rearing records elucidates probable redistribution routes and sources of both weevil species from initially released and established adopted range populations.     

Temperature and host-plant effects on development and population growth of Mecinus janthinus (Coleoptera: Curculionidae), a biological control agent for invasive Linaria spp.

Mecinus janthinus Germar is a European stem-mining weevil that has been established in North America as a biological control agent against the invasive European weeds Linaria vulgaris P. Mill. and Linaria dalmatica (L.) P. Mill. (Scrophulariaceae). Establishment success and impact of the weevil have varied widely among sites. We investigated the hypothesis that some of this variation may be due to a lack of sufficient time for M. janthinus to develop to the adult (overwintering) stage in less favorable climates. Development time of M. janthinus was measured in L. vulgaris and L. dalmatica at four constant temperatures, and logistic regression was used to derive a model for the effect of temperature on development. Development rates were simulated using historic climate data for a site in central Alberta (where establishment was marginal on L. vulgaris) and one in southern British Columbia (where outbreaks occurred, resulting in heavy damage to L. dalmatica). The model showed that, on average, the British Columbia site had 50 more days available for the weevil to lay eggs that could reach the adult stage in time for overwintering than did the Alberta site. This may explain the more rapid population buildup at the British Columbia site. This model could be used to predict the climatic suitability of other areas for establishment of M. janthinus. An unexplained result was the very low survival rate of eggs laid in L. dalmatica under the same experimental conditions.     

The importance of species identity in the biocontrol process: identifying the subspecies of Acacia nilotica (Leguminosae: Mimosoideae) by genetic distance and the implications for biological control

Aims A molecular genetic distance study has been used in an initial survey to identify subspecies and genotypes of the weed Acacia nilotica in Australia, information needed to find suitable biocontrol agents. We use patterns of DNA sequence variation (in two DNA fragments) from each of the nine described subspecies of Acacia nilotica (L.) Delile (Leguminosae: Mimosoideae) that is to determine their genetic similarity, to verify if the Australian populations are A. nilotica ssp. indica (Benth.) Brenan, and to establish if any other subspecies are present in Australia. Location Australia and southern Africa through the Arabian peninsular to the Indo‐Pakistan subcontinent. Methods Representative specimens from the global distribution of the nine A. nilotica subspecies were sourced primarily from herbaria sheet specimens where available, and secondarily from field collections. These specimens together with related outgroups from Mimosoideae were genetically analysed using the DNA fragments trnL and internal transcribed spacer one (ITS1). We calculated a similarity index as set out in paup * using upgma (Unweighted Pair‐Group Method Arithmetic average) methods to cluster taxa to produce a genetic distance phenogram. Results Sequence results from ITS1 and trnL DNA fragments identified seven of the described subspecies of A. nilotica. Acacia nilotica ssp. cupressiformis (J. Stewart) Ali & Faruqi and A. nilotica ssp. adstringens (Schumach. & Thonn.) Roberty were not found to be genotypically distinct from A. nilotica ssp. indica and A. nilotica ssp. nilotica, respectively, based on the two DNA fragments. Subspecific ITS1 genotypes were geographically distributed similarly to previous reports that were based on morphology, with the exception that the hemispherica ITS1 genotype also occurred in Somalia. We confirmed that the Australian A. nilotica populations are mostly comprised of subspecies indica, but in addition, some individuals were found to be genetically identical to an unidentified Pakistan genotype not previously reported as occurring in Australia. Main conclusions Australian A. nilotica populations originated from India and Pakistan and we recommend further analysis to determine the complete genetic diversity profile and origins of the Australian populations. We highlight the importance of determining any hybridization between Australian populations of A. nilotica and native subgenus Acacia species. This study demonstrates the importance of genotyping weed species targeted for biocontrol and/or listed host specificity test species that may be easily misidentified. Biocontrol practitioners can justify genetic studies by considering the costs should a project fail through misidentification.     

Karyological notes on another eight species of Achillea (Asteraceae) from Turkey

The chromosome number and morphology in eight species of the sections Ptarmica (Mill.) W. D. J. Koch, Anthemoideae (DC.) Heimerl, Arthrolepis Boiss., Santolinoideae (DC.) Heimerl and Achillea of the genus Achillea L. (Asteraceae) were investigated using karyological techniques. Sample plants and seeds of A. biserrata M. Bieb., A. fraasii var. troiana Aschers. & Heimerl, A. multifida (DC.) Boiss., A. brachyphylla Boiss. & Hausskn., A. pseudaleppica Hub.-Mor., A. cretica L., A. latiloba Ledeb. ex Nordm., and A. kotschyi Boiss. subsp. kotschyi) were collected from natural habitats in 2003 and 2004. The chromosome number found in seven species was 2n = 18, while only A. kotschyi had 2n = 36. All chromosomes had median point (M), median region (m), and submedian (sm) centromers. In addition, only A. biserrata species had one subterminal (st) chromosome. An increase in asymmetry was not observed in the karyotypes of the species studied. None of the studied species had any B chromosomes.     

Molecular and morphological evidence for multiple species within Paranoplocephala omphalodes (Cestoda, Anoplocephalidae) in Microtus voles (Arvicolinae)

Haukisalmi, V., Wickström, L. M., Henttonen, H., Hantula, J. & Gubányi, A. (2004). Molecular and morphological evidence for multiple species within Paranoplocephala omphalodes (Cestoda, Anoplocephalidae) in Microtus voles (Arvicolinae). —Zoologica Scripta, 33, 277–290. The present study was designed to test the hypothesis that the anoplocephalid cestode Paranoplocephala omphalodes (Hermann, 1783), a Holarctic parasite of Microtus voles, is a complex of host‐specific species, rather than a single host‐generalist species, using uni‐ and multivariate morphometrics and DNA sequence data from the mitochondrial cytochrome oxidase I gene. The phylogenetic methods applied to the mtDNA sequence data showed consistently that the cestodes morphologically recognizable as P. omphalodes include four well‐supported monophyletic groups, representing at least three distinct, largely host‐specific species. Multivariate morphometrics (discriminant analysis) successfully distinguished the four main mtDNA clades of P. omphalodes‐like cestodes. The true P. omphalodes is shown to be a parasite of Microtus arvalis, M. agrestis and Clethrionomys glareolus in Europe. Microtus oeconomus harbours two host‐specific, allopatric and possibly conspecific clades, one with a Holarctic and another with an (eastern) Beringian (Alaskan) distribution. The eastern Beringian endemic M. miurus is also parasitized with a host‐specific, morphologically divergent species of Paranoplocephala. The cestode clades recognized in M. oeconomus and M. miurus represent 2–3 undescribed species. Molecular phylogenetic analyses supported the monophyly of the ‘northern clade’ of Paranoplocephala spp., an assemblage including P. kalelai from Clethrionomys spp., P. macrocephala from Microtus spp. and all clades of P. omphalodes‐like cestodes except those representing the true P. omphalodes from Europe. The intra‐ and interspecific phylogeny within the northern clade is compared tentatively with the known evolutionary history of the hosts.     

The taxa of Scottish bracken in a European perspective

Summary

In contrast to the traditional view that Scottish Bracken (Pteridium Scop., Hypolepidaceae sensu Page, 1976) is a single, uniform taxon, evidence is presented that two species, each represented by multiple subspecies, are present in Scotland. These belong to two different species complexes within Pteridium, the P. aquilinum complex and the P. latiusculum complex. The P. aquilinum complex is represented by P. aquilinum (L.) Kuhn, with at least three subspecies: subsp. aquilinum, subsp. atlanticum C.N. Page and subsp. fulvum C.N. Page. The P. latiusculum complex is represented by P. pinetorum C.N. Page & R.R. Mill with at least two subspecies, subsp. pinetorum and subsp. osmundaceum (Christ) C.N. Page. Only P. aquilinum subsp. aquilinum is an aggressive weed which is a widespread problem to man; the others are rare. The paper establishes the nomenclatural priorities, typification, taxonomy, morphology, known distribution and ecology of all bracken taxa so far known from Scotland. The typification of P. aquilinum is discussed. There is no conflict between the two lectotypifications of Try on (1941) and Sheffield et al. (1989); both relate to the common bracken of the mid- and southern-latitudes of Europe, for which the existing epithet aquilinum must therefore be retained. It is pointed out that some of the other European taxa of bracken might well also yet be found within the British Isles, as well as, perhaps, other (especially possible diploid) taxa as yet undescribed.     

Haplodontium zangii X.R.Wang & J.C.Zhao,sp. nov. (Bryaceae,Bryopsida) from Xizang,China

Haplodontium zangii X.R.Wang &; J.C.Zhao, a new moss species from Xizang, China, is described and illustrated. Previously, specimens of H. zangii have been identified as Mielichhoferia himalayana Mitt. However, H. zangii is distinctly different from M. himalayana in having excurrent costae with short awns (vs long denticulate awns), short-pyriform capsules, 0.8–1?mm (vs long-pyriform capsules, 2.5–3?mm), and densely papillose exostome teeth (vs smooth or vertically striped exostome teeth). Haplodontium zangii is similar to H. macrocarpum (Hook.) J.R.Spence, which was traditionally placed in Mielichhoferia Nees &; Hornsch. as M. macrocarpa (Hook.) Bruch &; Schimp. The main differences between H. zangii and H. macrocarpum are in the morphology of the leaves, capsules, guide cells, and stomata. Mielichhoferia himalayana and another Chinese species of Mielichhoferia, M. sinensis Dix., are also transferred to Haplodontium Hampe, a new genus in the bryoflora of China, as H. himalayanum (Mitt.) X.R.Wang &; J.C.Zhao and H. sinensis (Dix.) X.R.Wang &; J.C.Zhao. A morphological comparison and a key to the three species of Haplodontium in China as well as to H. macrocarpum, a species that is likely to be found in China, are provided.     

A cytogenetic study of four species of cockatoos and Amazon parrots

The karyotypes of three species of cockatoos, Cacatua moluccensis, Cacatua goffini, and Cacatua sanguinea, and one Amazon parrot, Amazona aestiva, are described for the first time. These karyotypes are compared to the twenty-three species of psittacines published previously. Cacatua moluccensis appears to be a link in the evolutionary tree between Probosciger aterrimus and the other cockatoo species studied. This study reaffirms that the cockatoos are probably most closely related to the loris (Loriculus sp.) and Amazon parrots based on karyotype (M. W. M. Van Dongen & L. E. M. De Boer, (Genetica 65: 109–117) 1984).     

Differential response of domestic and wild Lycopersicon species to chilling under low light: growth, carbohydrate content, photosynthesis and the xanthophyll cycle

The response of five Lycopersicon species to 14 days moderate chilling at 10°C under low light (75 μmol m^?2 s^?1) and subsequent recovery was examined by measurements on relative shoot growth rate, leaf dry matter and carbohydrate content, CO₂-exchange and pigment composition. In addition, the susceptibility to dark chilling and temperature dependence of chloroplast electron transport were analyzed by Chl a fluorescence measurements. During 7 days of recovery at 25/20°C subsequent to chilling, the domestic tomato Lycopersiconesculentum (L.) Mill. cv. Abunda exhibited a small capacity for shoot regrowth (39%) compared to the low-altitude wild species L. pimpinellifolium (Jusl.) Mill. PI187002 (82%) and three wild species originating from high altitude: L. peruvianum Mill. LA 385 (92%), L. hirsutum Humb. & Bonpl. LA 1777 (67%) and L. chilense Dunn. LA 1970 (71%). The inter-specific differences in chilling sensitivity at the chloroplast level, analyzed by the decline of the maximum rate of induced Chl fluorescence rise (F_R) after 40 h at 0°C and the temperature at which q_P reached the value 0.5, correlated in general well with the measured differences at whole plant level, measured by the post-chilling regrowth capacity. Chilling resulted in a larger increase in leaf dry matter content in L. esculentum (45%) and L. pimpinellifolium (37%) compared to the high-altitude species (13–16%), which could be attributed to a stronger accumulation of both soluble sugars and starch in mature leaves of the domestic and low-altitude species. Photosynthetic and dark respiration rates during chilling could not account for this difference. The recovery of photosynthesis was better in the high-altitude species. Chl content per unit leaf area decreased more throughout the experiment in the domestic and low-altitude species (63–73%) than in their relatives from high altitude (8–29%). In response to chilling, the domestic and low-altitude species showed an increase in the total xanthophyll cycle pool on Chl basis, whereas the de-epoxidation state of the xanthophyll cycle increased in the high-altitude wild species. Both responses resulted in increased zeaxanthin levels in chilled leaves of all Lycopersicon species.