Use of telemetry in the development and application of biological criteria for habitat hydraulic modeling

Neodiaptomus songkhramensis n. sp. from 86 temporary waters in the vicinity of Song Khram River in northeast Thailand is described and figured. It was found during May and June (rainy season) in Sakon Nakhon, Nakhon Pranom and Udon Thani Provinces. The new species usually co-occurs with 1–5 other diaptomids; the most frequently co-occurring species are Neodiaptomus blachei, Tropodiaptomus oryzanus, Neodiaptomus yangtsekiangensis, Dentodiaptomus javanus and Eodiaptomus phuphanensis.     

Neodiaptomus intermedius n. sp. (Calanoida: Copepoda) from South India

A new species of Neodiaptomus, N. intermedius n. sp. is described and illustrated. It is compared with related species of the strigilipes — physalipus species group.     

Larval stages of Neodiaptomus lindbergi Brehm, 1953 (Copepoda,Calanoida)

All the postembryonic developmental instars of Neodiaptomus lindbergi Brehm, 1953, reared in the laboratory from eggs, are described and illustrated. Further, the larval affinities of this species vis-a-vis certain other Indian diaptomid species are mentioned.     

On Neodiaptomus schmackeri (Poppe & Richard, 1892) (Crustacea,Copepoda)

Neodiaptomus schmackeri and related species are redescribed. The synonymy of this species with N. strigilipes and N. handeli is discussed.     

The freshwater Calanoida (Crustacea: Copepoda) of Thailand

14 Species of freshwater Calanoida in Thailand are reported in this study. The most common species is Neodiaptomus botulifer. Most of these belong to the Southeast Asian species, the remainder are either Indian or East Asian copepods. The zoogeographical demarcation of copepods in Thailand is not very distinct due to its interconnecting riverine and reservoir systems as well as frequent flood. The peculiarity of the Thai Calanoida and their distribution is discussed in a Southeast Asia context. A taxonomic key to the Thai Calanoida is formulated.     

Distribution,diversity and density of wolbachial infections in cladocerans and copepods from Thailand

Species of the genus Wolbachia comprise a group of Rickettsia-like, maternally-inherited bacteria that cause several reproductive alterations in arthropod hosts. The best known are cytoplasmic incompatibility and feminization. Here, the first systematic surveys of wolbachial infections in cladocerans and copepods from six geographic regions of Thailand, including Northern, Northeastern, Western, Central, Eastern and Southern are reported. Using gene amplification assays with wsp and groE primers, wolbachiae were detected in 239 (4 spp.) of 1885 (57 spp.) copepods and cladocerans from all regions of Thailand surveyed. Screening results obtained with wsp primers or groE primers were similar in all cases. The presence of wolbachiae was only detected in copepods, not in cladocerans. Sex ratio analyses of the progeny of two species of copepods, Mesocyclops aspericornis and Mesocyclops thermocyclopoides, naturally or artificially infected with wolbachiae showed infection causes feminization (female-bias). The relative density if infection in naturally infected populations of three copepod species, M. thermocyclopoides, Heliodiaptomus elegans and Neodiaptomus blachei, were determined using real-time quantitative PCR assay based on the wsp gene. The density of wolbachiae in M. thermocyclopoides was significantly higher than in the other two species. These results suggest that wolbachial infections are distributed throughout Thailand, and that possibly the natural occurrence of these in copepods may be due to their predation on mosquito larvae. This apparent novel biology may have importance as a genetic drive system for control of vector borne diseases in the future.     

The freshwater calanoida (crustacea : copepoda) of Singapore and Peninsular Malaysia

The systematics and geographical distribution of Malaysian and Singapore freshwater calanoid copepods are discussed in details. Neodiaptomus handeli Brehm, N. laii Kiefer, N. blachei (Brehm), N. botulifer Kiefer, N. mephistopheles Brehm, Pseudodiaptomus (Schmackeria) dauglishi Sewell, P. (S.) tollingerae Sewell and Tropodiaptomus spp. Kiefer are all present in the northwestern part of the Peninsula. There are only 4 species, namely, N. handeli, N. botulifer, N. meggitti Kiefer and Tropodiaptomus sp. in the southern half of the Peninsula. The whole of the east coast also has 4 species, i.e. N. handeli, N. malaindosinensis (n.n.), P. (S.) tollingerae and one species of Tropodiaptomus. The only species that cut across a wide range of geographical barriers are N. handeli and Tropodiaptomus.     

Zooplankton Distribution in Tropical Reservoirs,South China

The zooplankton of 18 reservoirs of South China was investigated in 2000. 61 Rotifera species, 23 Cladoceras and 14 Copepodas were identified. The most frequent Rotifera genera were Keratella, Brachionus, Trichocerca, Diurella, Ascomorpha, Polyarthra, Ploesoma, Asplanchna, Pompholyx and Conochilus. Bosmina longirostris, Bosminopsis deitersi, Diaphanosoma birgei, D. brachyurum and Moina micrura were typical of Cladocera in the reservoirs. Phyllodiaptomus tunguidus, Neodiaptomus schmackeri and Mesocyclops leuckarti were the most frequent Copepoda and M. leuckarti dominated Copepoda in most reservoirs. High zooplankton species richness with low abundance was characteristic of the throughflowing reservoir, whereas low species richness with low abundance was found in the reservoir with the longest retention time. Relative high abundance and medium species diversity were the distinction of intermediate retention time reservoirs.     

Evolution and Phylogenetic Diversity of Yam Species (Dioscorea spp.): Implication for Conservation and Agricultural Practices

Yams (Dioscorea spp.) consist of approximately 600 species. Presently, these species are threatened by genetic erosion due to many factors such as pest attacks and farming practices. In parallel, complex taxonomic boundaries in this genus makes it more challenging to properly address the genetic diversity of yam and manage its germplasm. As a first step toward evaluating and preserving the genetic diversity yam species, we use a phylogenetic diversity (PD) approach that has the advantage to investigate phylogenetic relationships and test hypotheses of species monophyly while alleviating to the problem of ploidy variation within and among species. The Bayesian phylogenetic analysis of 62 accessions from 7 species from three regions of Cameroon showed that most Dioscorea sections were monophyletic, but species within sections were generally non-monophyletic. The wild species D. praehensilis and cultivated D. cayenensis were the species with the highest PD. At the opposite, D. esculenta has a low PD and future studies should focus on this species to properly address its conservation status. We also show that wild species show a stronger genetic structure than cultivated species, which potentially reflects the management of the yam germplasm by farmers. These findings show that phylogenetic diversity is a promising approach for an initial investigation of genetic diversity in a crop consisting of closely related species.     

Distribution,spread, and impact of the invasive hornet Vespa velutina in South Korea

Hornets (Vespa spp) are top insect predators that can control pests, but their venomous stings and defensive behavior cause numerous human deaths throughout Asia. Hornets usually inhabit rural areas which reduces potential conflict with humans. In 2003, the invasive hornet, Vespa velutina, arrived in southern Korea (Yeongdo region) and became established. It is currently spreading northwards at a rate of 10–20 km per year. Despite originating in tropical/subtropical areas of Indo-China, its nesting biology and life cycle in South Korea are similar to those found throughout its native range, with mature colonies containing 1000–1200 adults. In 7 years, V. velutina has become the most abundant hornet species in Southern Korea by displacing native Vespa species such as V. simillima, which has a similar nesting biology. We also found a significant positive correlation between the abundance of V. velutina and the degree of urbanization, indicating that this invasive species was well adapted to urban environments. This was supported by our finding that 41% of emergency call-outs (119 Rescue Services) to deal with social wasps/hornet problems were due to V. velutina, which was twice as high as the number of calls about the next most abundant species. The rapid spread of V. velutina across southern Korea indicates that this species will continue to spread north-westward in the Korean peninsula and will become a major problem as more people and beekeepers come into contact with this aggressive invasive hornet.     

Can the problem of hybridization in threatened species be evaluated using a fieldwork research? A case study in snapdragons

Hybridization, natural or artificial, is considered disadvantageous for species biodiversity when it threatens the population integrity of endangered species. Frequently, studies investigating whether hybridization poses a legitimate risk to rare species are based on genetic data obtained in molecular biology laboratories. In this study, we used field research to approach the problem that hybridization could cause for the viability of a population of a rare species and to be able to propose the most appropriate initial conservation strategy. Specifically, using the model genus Antirrhinum, the reproductive barriers between the rare A. pulverulentum and its common congener A. litigiosum have been analysed under the reproductive isolation index (RI). A. pulverulentum had a high value of total RI, indicating that there are barriers to gene flow from A. litigiosum towards this species, and also had a high value for the intrinsic RI, reflecting a low inherent capacity for production of hybrid plants; in addition, the possibility of successful backcrosses between this species with hybrids produced from A. litigiosum ovules were low, given the high intrinsic RI of A. litigiosum. These data indicate the current existence of strong and permanent barriers to hybridization between the two species, suggesting that hybridization does not seem to be a serious problem for the conservation of A. pulverulentum in the studied population, nor for the near future. This study shows how the RI index can provide useful information for conservation purposes and proposes different management recommendations.     

Inhibition of phytoplankton species by co-culture with a fungus

Harmful algal blooms are a serious worldwide environmental problem. Algicidal microorganisms, especially bacteria, have attracted extensive attention as possible agents for inhibiting water blooms. Such capabilities, however, are rarely reported for fungi. In this work, a fungal strain, Trichaptum abietinum 1302BG, is studied for its capability to inhibit four phytoplankton species: Microcystis aeruginosa FACH-918, Microcystis flos-aquae FACH-1028, Oocystis borgei FACH-1108, and Microcystis aeruginosa PCC 7806. The results show that the chlorophyll-a from these phytoplankton species co-cultured with Trichaptum abietinum 1302BG decreases rapidly 24 h after inoculation, and phytoplankton cells almost completely disappear 48 h after incubation. These results suggest that the fungus strain has great potential for the degradation of phytoplankton species. To the best of our knowledge, this is the first report of a white-rot fungus that can inhibit harmful algae blooms species.     

Are the mitochondrial cox1 and cob genes suitable markers for species of Dinophysis Ehrenberg?

The identification of Dinophysis species with similar morphology but different toxic (Diarrhetic Shellfish Poisoning, DSP) potential is a crucial task in harmful algae monitoring programmes. The taxonomic assignment of Dinophysis species using molecular markers is a difficult task due to extremely low interspecific variability within their nuclear ribosomal genes and intergenic regions. Mitochondrial cox1 gene has been proposed as a better specific marker for Dinophysis species based on its higher resolution for two morphologically related species (Dinophysis acuminata and Dinophysis ovum) of the “Dinophysis acuminata complex”. In this study, the potential of two mitochondrial genes (mt cox1 and cob) to discriminate among six Dinophysis species (field isolates and cultures) associated with DSP events was explored. Neither mt cox1 nor cob genes provided enough resolution for all species of Dinophysis. The cob gene showed very poor resolution and grouped all Dinophysis spp. in a common clade. In contrast, the cox1 phylogeny distinguished 5 clades in the Dinophysiales – the “acuminata complex”, the “caudata group”, “acuta + norvegica” and Phalacromaspp. However, within the “D. acuminata complex” mtcox1 is so far the unique marker that differentiates D. acuminata from other species: isolates of D. ovum and Dinophysis sacculus had almost identical sequences (only four mismatches), but they were well separated from D. acuminata. D. acuminata and Dinophysis skagii (considered a life cycle stage of the former) showed identical cox1 sequences. Probes towards this gene can be useful in Mediterranean and Western Iberia sites where the co-occurrence of close morphotypes of D. acuminata and D. sacculus pose a problem for monitoring analyses. This is the first report on cultures of D. sacculus and its phylogenetic relation with other species of the D. acuminata complex.     

Sesquiterpene and polyacetylene profile of the Bidens pilosa complex (Asteraceae: Heliantheae) from Southeast of Brazil

The pantropical weed Bidens pilosa (Asteraceae) is a species with several taxonomic problems. Recently it has been shown to be a complex of different species. To shed light on this problem in Brazil, dichloromethane extract of leaves of several populations corresponding to three proposed species for the complex in southeastern Brazil (B. pilosa, Bidens alba and Bidens subalternans) were analyzed by GC–MS. Twenty-four substances were detected, of which four resemble polyacetylenes, the others sesquiterpenes. Five sesquiterpenes tentatively identified as E-caryophyllene, α-humulene, germacrene-D, bicyclogermacrene and α-muurolene were found in all three Bidens species. The polyacetylene phenylhepta-1,3,5-triyne was identified only in B. alba. Multivariate analysis (cluster and principal component analyses) separated the three entities, suggesting that these compounds could represent a useful tool to distinguish species in the B. pilosa complex.     

Evolution and instability in ring species complexes: An in silico approach to the study of speciation

Ring species are a biological complex that theoretically forms when an ancestral population extends its range around a geographic barrier and, despite low-level gene flow, differentiates until reproductive isolation exists when terminal populations come into secondary contact. Due to their rarity in nature, little is known about the biological factors that promote the formation of ring species. We use evolutionary algorithms operating on two simple computational problems (SAW and K-max) to study the process of speciation under the conditions which may yield ring species. We vary evolutionary parameters to measure their influence on ring species’ development and stability over evolutionary time. Using the SAW problem, ring species consistently form, i.e. fertility is negatively correlated with distance (R-values between −0.097 and −0.821, p<0.001), and terminal populations show substantial infertility. However, all SAW simulations demonstrate instability in the complex after sympatric zones are established between terminal populations. Higher mutation rates and larger dispersal/breeding radii promote ring species’ formation and stability. Using a problem with a simple fitness landscape, the K-max problem, ring species do not form. Instead, speciation around the ring occurs before ring closure as good genotypes become locally dominant.     

Bee pollination of the endangered orchid Calanthe discolor through a generalized food-deceptive system

Calanthe discolor is a Japanese terrestrial orchid that is cultivated for its beautiful flowers arranged in racemose inflorescences. Although its propagation for horticultural purposes has been studied extensively resulting in the successful production of seedlings, little is known about the pollinators and breeding system of C. discolor in its natural habitat. The current study, which combined field observations and pollination experiments, was conducted to gain further insight into the reproduction of this important orchid species. Three bee species: Eucera nipponensis, Osmia cornifrons and Apis cerana japonica, were found to be effective pollinators, transferring the pollinaria on their heads. Pollination experiments also revealed that this species was self-compatible, although it was neither autogamous nor apogamous. The fruit set for the open-pollinated flowers was less than 10 %, suggesting a high degree of pollinator limitation, possibly as a result of the deceptive nature of this species. These results provide evidence that pollinator specificity is the primary mechanism of reproductive isolation between C. discolor and its close relative Calanthe striata, because the latter species is known to be exclusively pollinated by carpenter bee.     

Agonosoma trilineatum (Heteroptera: Scutelleridae) a biological control agent of the weed bellyache bush,Jatropha gossypiifolia (Euphorbiaceae)

Bellyache bush, Jatropha gossypiifolia L., is a serious weed of northern Australia. Agonosoma trilineatum (F.) is an insect from tropical America released in Australia in 2003 as a biological control agent against bellyache bush. It feeds on seeds and has the potential to reduce seed production, thereby potentially reducing the rate of spread and recruitment. To test the host specificity of A. trilineatum, four biological responses to host plant species were determined: development of nymphs, oviposition preferences, adult feeding and frequency of mating. Development of nymphs to adults and adult feeding only occurred on three Jatropha spp. These species also supported mating and oogenesis but only J. gossypiifolia was accepted for oviposition. Mating did not occur in the presence of other plant species. The evidence indicates that there is little risk associated with the release of this insect species in Australia and probably other countries where this weed is a problem. The probability of this insect expanding its host range is low because multiple aspects of the biology would need to change simultaneously. A. trilineatum was released in Australia between 2003 and 2007. A Climex model indicated that coastal areas of Queensland and the Northern Territory would be climatically most suitable for this insect.