197 research outputs found

    Two new tiger beetle species (Coleoptera: Cicindelidae) from Myanmar and notes on another species. 151. Contribution towards the knowledge of the Cicindelidae

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    Cylindera (Ifasina) thitarooae Wiesner and Hori, new species, Jansenia phyuae Wiesner and Hori, new species, and the previously unknown male of Jansenia myanmarensis Wiesner, 2004 (Coleoptera: Cicindelidae) are described. Cylindera (I.) thitarooae may be recognized by shape of labrum and aedeagus. Jansenia phyuae may be recognized by its elytral contour and shape of elytral maculation

    Three new tiger beetle species of the genus \u3ci\u3eProthyma\u3c/i\u3e Hope, 1838, subgenus \u3ci\u3eGenoprothyma\u3c/i\u3e Rivalier, 1964 (Coleoptera: Cicindelidae) described from Myanmar. 152. Contribution towards the knowledge of the Cicindelidae

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    Prothyma (Genoprothyma) thandamoeae Wiesner, Phyu and Hori, new species, Prothyma (Genoprothyma) sotai Wiesner, Phyu and Hori, new species, and Prothyma (Genoprothyma) asamii Wiesner, Phyu and Hori, new species (Coleoptera: Cicindelidae) are described from Myanmar. A key to all members of the genus known to occur in Myanmar is given

    Sperm phenotypic plasticity in a cichlid: a territorial male's counterstrategy to spawning takeover

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    Studies of sperm competition in species with alternative reproductive tactics (ARTs) often pay attention to the differences in investments in sperm between sneakers facing a higher sperm competition risk and bourgeois males facing a lower risk. Here, we examined within-tactic as well as among-tactic variations in sperm investments in the Lake Tanganyika shell-brooding cichlid Telmatochromis vittatus, a species with 2 types of parasitic tactics. Territorial male T. vittatus suffer reproductive parasitism by both smaller sneaker males and larger pirate males ("pirates” take over the spawning event during which territorial males perform sneaking as a counterstrategy). We hypothesized that both territorial males living under the risk of pirates and sneakers face increased risk of sperm competition and therefore should produce high-quality sperm compared with both territorial males that experienced no piracy risk and pirates. As expected, field studies showed that the former 2 males produced longer lived sperm than the other males. Aquarium experiments demonstrated that a visual stimulus of a pirate was enough to induce an increase in sperm longevity in territorial males compared with when no such stimulus was given. These results indicate that territorial male T. vittatus can plastically adjust at least one sperm quality trait in response to piracy risk. Moreover, long-term monitoring of males in the field showed that small territorial males grow into large territorial males and finally into pirates, so ARTs are not fixed over life. Accordingly, male T. vittatus appear to ontogenetically change their sperm longevity in response to size-dependent sperm competition risk

    Evolution of feeding specialization in Tanganyikan scale-eating cichlids: a molecular phylogenetic approach

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    <p>Abstract</p> <p>Background</p> <p>Cichlid fishes in Lake Tanganyika exhibit remarkable diversity in their feeding habits. Among them, seven species in the genus <it>Perissodus </it>are known for their unique feeding habit of scale eating with specialized feeding morphology and behaviour. Although the origin of the scale-eating habit has long been questioned, its evolutionary process is still unknown. In the present study, we conducted interspecific phylogenetic analyses for all nine known species in the tribe Perissodini (seven <it>Perissodus </it>and two <it>Haplotaxodon </it>species) using amplified fragment length polymorphism (AFLP) analyses of the nuclear DNA. On the basis of the resultant phylogenetic frameworks, the evolution of their feeding habits was traced using data from analyses of stomach contents, habitat depths, and observations of oral jaw tooth morphology.</p> <p>Results</p> <p>AFLP analyses resolved the phylogenetic relationships of the Perissodini, strongly supporting monophyly for each species. The character reconstruction of feeding ecology based on the AFLP tree suggested that scale eating evolved from general carnivorous feeding to highly specialized scale eating. Furthermore, scale eating is suggested to have evolved in deepwater habitats in the lake. Oral jaw tooth shape was also estimated to have diverged in step with specialization for scale eating.</p> <p>Conclusion</p> <p>The present evolutionary analyses of feeding ecology and morphology based on the obtained phylogenetic tree demonstrate for the first time the evolutionary process leading from generalised to highly specialized scale eating, with diversification in feeding morphology and behaviour among species.</p

    Mutations in the stator protein PomA affect switching of rotational direction in bacterial flagellar motor

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    The flagellar motor rotates bi-directionally in counter-clockwise (CCW) and clockwise (CW) directions. The motor consists of a stator and a rotor. Recent structural studies have revealed that the stator is composed of a pentameric ring of A subunits and a dimer axis of B subunits. Highly conserved charged and neighboring residues of the A subunit interacts with the rotor, generating torque through a gear-like mechanism. The rotational direction is controlled by chemotaxis signaling transmitted to the rotor, with less evidence for the stator being involved. In this study, we report novel mutations that affect the switching of the rotational direction at the putative interaction site of the stator to generate rotational force. Our results highlight an aspect of flagellar motor function that appropriate switching of the interaction states between the stator and rotor is critical for controlling the rotational direction

    Colorful patterns indicate common ancestry in diverged tiger beetle taxa: Molecular phylogeny, biogeography, and evolution of elytral coloration of the genus Cicindela subgenus Sophiodela and its allies.

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    We investigated the phylogenetic relationships among tiger beetles of the subtribe Cicindelina (=Cicindela s. lat.; Coleoptera: Cicindelidae) mainly from the Oriental and Sino-Japanese zoogeographic regions using one mitochondrial and three nuclear gene sequences to examine the position of the subgenus Sophiodela, currently classified in the genus Cicindela s. str., their biogeography, and the evolution of their brilliant coloration. The subgenus Sophiodela was not related to the other subgenera of Cicindela s. str. but was closely related to the genus Cosmodela. In addition, the Oriental genus Calochroa was polyphyletic with three lineages, one of which was closely related to Sophiodela and Cosmodela. The clade comprising Sophiodela, Cosmodela and two Calochroa species, referred to here as the Sophiodela group, was strongly supported, and most species in this clade had similar brilliant coloration. The Sophiodela group was related to the genera Calomera, Cicindela (excluding Sophiodela) and Cicindelidia, and these were related to Lophyra, Hipparidium and Calochroa, except species in the Sophiodela group. Divergence time estimation suggested that these worldwide Cicindelina groups diverged in the early Oligocene, and the Sophiodela group, which is found in the Oriental and Sino-Japanese zoogeographic regions, in the mid Miocene. Some components of the elytral pattern related to maculation and coloration in the Cicindelina taxa studied contained weak, but significant, phylogenetic signals and were partly associated with habitat types. Therefore, the brilliant coloration of the Sophiodela was related to both phylogeny and habitat adaptation, although the function of coloration needs to be studied
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