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Zoological Science

Yasuhiro Sugime, Dai Watanabe, Yoko Yasuno, Tetsuro Shinada, Toru Miura, Nobuaki K Tanaka
Juvenile hormone (JH) plays a crucial role in the determination of developmental timing in insects. In Drosophila melanogaster, reports indicate that JH titers are the highest immediately following eclosion and that the mating experience increases the titers in females. However, the titers have not been successively measured for an extended period of time after eclosion. This study reveals that JH titers are increased after eclosion in virgin females when supplied with food that is occupied by eggs and larvae as well as in mated females...
February 2017: Zoological Science
Atsushi C Suzuki, Hiroshi Kagoshima, Glen Chilton, Gary T Grothman, Carl Johansson, Megumu Tsujimoto
Extreme environments sometimes support surprisingly high meiofaunal diversity. We sampled runoff from the acidic hot springs of Unzen, Japan. This is the type locality of Thermozodium esakii Rahm, 1937, the only tardigrade in the class Mesotardigrada, which remains contentious in the absence of corroboration or supporting specimens. Our sampling revealed at least three species of arthropods, four rotifers, and five nematodes living in the hot (ca. 40°C) and acidic (ca. pH 2.5) water, but no tardigrades.
February 2017: Zoological Science
Gary T Grothman, Carl Johansson, Glen Chilton, Hiroshi Kagoshima, Megumu Tsujimoto, Atsushi C Suzuki
The tardigrade class Mesotardigrada was erected on the basis of the description of Thermozodium esakii by Gilbert Rahm in 1937. In some characteristics, T. esakii is intermediate between members of the classes Eutardigrada and Heterotardigrada. The class Mesotardigrada is known only from Rahm's published drawings of T. esakii; no voucher specimens are known, and subsequent attempts to collect it at the locus typicus have been unsuccessful. Among the possible explanations for this situation are that Rahm may have collected specimens of a more typical tardigrade, but misinterpreted what he saw...
February 2017: Zoological Science
Taishi Shiomi, Akihiko Muto, Shunya Hozumi, Hiroshi Kimura, Yutaka Kikuchi
Previous studies in Xenopus have shown that forced expression of Nodal signaling can change ectodermal cells to a mesodermal fate by the early gastrula stage, suggesting mesodermal competence in early ectoderm cells. This mesodermal competence in ectodermal cells has been shown to be regulated at the level of nucleocytoplasmic localization of Smad2 in Xenopus. However, the regulation of mesodermal competence through epigenetic mechanisms has not been fully elucidated. Here, we used a constitutively active form of zebrafish Smad2 (Smad2ca) to overcome the inhibition of Nodal signaling via the nuclear exclusion of Smad2...
February 2017: Zoological Science
Kanto Nishikawa, Tatjana Dujsebayeva, Masafumi Matsui, Natsuhiko Yoshikawa, Atsushi Tominaga
Chinese populations of the endangered Siberian salamander Ranodon sibiricus are reported to have diverged only about 120 years ago, and to have the lowest genetic diversity of any amphibian. However, these conclusions require verification, as the main range of the species is in Kazakhstan. Moreover, the generation time used for estimating divergence time has a weak ground. In order to clarify these problems, we investigated the molecular phylogenetic relationship and historical demography of the species covering its whole distribution range using the mitochondrial DNA region reported for Chinese population (1072 bp sequences of the control region), while conducting skeletochronological analysis to estimate accurate generation time...
February 2017: Zoological Science
Hiroshi Sunada, Ken Lukowiak, Etsuro Ito
The pond snail Lymnaea stagnalis can acquire conditioned taste aversion (CTA) as a long-term memory. CTA is caused by the temporal pairing of a stimulus, such as sucrose (the conditioned stimulus; CS), with another stimulus, such as electric shock (the unconditioned stimulus; US). Previous studies have demonstrated changes in both cellular and molecular properties in a pair of neurons known as the cerebral giant cells (CGCs), suggesting that these neurons play a key role in CTA. Here we examined the necessity of the pair of CGC somata for the learning, memory formation and memory recall of CTA by using the soma ablation technique...
February 2017: Zoological Science
Masakazu Asahara
Geographic variation of the sizes of lower molar (M1 size) and relative lower molar sizes (size proportions among M1, M2, and M3) were examined in two species of closely related Japanese field mice (Apodemus speciosus and Apodemus argenteus). To determine the cause of the geographic variations observed, phylogeographic structure, interspecific competition, climate, and location (mainland or island) were compared. With regard to the phylogeographic structure, the sizes of the molar and the relative molar sizes in A...
February 2017: Zoological Science
Nozomi Kobayashi, Haruna Okabe, Isao Kawazu, Naoto Higashi, Keisuke Kato, Hirokazu Miyahara, Gen Nakamura, Hidehiro Kato, Senzo Uchida
The distribution and local movement patterns of humpback whales in waters off the west coast of Okinawa Island, southwest Japan, were investigated using line transect and photo-identification methodologies. Line transect surveys were conducted from 2011 to 2014 and photo-identification survey from 2006 to 2012. During the surveys, humpback whales aggregated in the areas around Ie and Kerama Islands, and tended to travel along the inshore coast of Okinawa Island when they move locally between those two sites...
February 2017: Zoological Science
Federico Buonanno, Andrea Anesi, Graziano Di Giuseppe, Graziano Guella, Claudio Ortenzi
Pseudokeronopsis erythrina produces three new secondary metabolites, erythrolactones A2, B2 and C2, and their respective sulfate esters (A1, B1, C1), the structures of which have been recently elucidated on the basis of NMR spectroscopic data coupled to high resolution mass measurements (HR-MALDI-TOF). An analysis of the discharge of the protozoan pigment granules revealed that the non-sulfonated erythrolactones are exclusively stored in these cortical organelles, which are commonly used by a number of ciliates as chemical weapons in offense/defense interactions with prey and predators...
February 2017: Zoological Science
Masakazu Asahara, Yuichiro Nishioka
We examined geographic variations of absolute and relative lower molar sizes (size proportions among M1, M2, and M3) in the Japanese macaque (Macaca fuscata) using skull specimens obtained from 13 locations. We compared the geographic patterns and climatic factors. The size of M1 significantly and negatively correlated to the annual and coldest month mean temperatures and precipitation for both males and females. The M2/M1 and M3/M1 scores significantly and positively correlated to the annual and coldest month mean temperatures...
February 2017: Zoological Science
Shigeru Kuratani, Takema Fukatsu
Zoological Letters, an open access online journal launched in 2015 is entering its third year of publication, and now seeks to drive new insights in evolutionary and comparative zoology by the inclusion of paleontological studies into its scope.
February 2017: Zoological Science
Susumu Ohtsuka, Hayato Tanaka, Geoffrey A Boxshall
A new species of the cyclopinid genus Cyclopicina, C. toyoshioae sp. nov., was collected from the hyperbenthic layer off northern Kyushu Island, Japan; its description is based on two adult female specimens. This is the first record of the genus from the Indo-Pacific region. The new species can be distinguished from its two known congeners in: (1) the relatively short antennules which do not reach the posterior margin of the dorsal cephalothoracic shield; (2) the shape of seminal receptacles; (3) the segmentation and armature of the cephalothoracic appendages; (4) the shape of the basal protrusion between the rami of legs 1-4; (5) the presence of three outer spines on the third exopodal segment of leg 4; and (6) the presence or absence of outer setae on the free exopodal segment of leg 5...
December 2016: Zoological Science
Takehito Okui, Sakiko Hosozawa, Satoka Kohama, Shingo Fujiyama, Shun Maekawa, Hiroshi Muto, Takashi Kato
Erythroid progenitors that respond to erythropoietin (Epo) are present in the liver of adult Xenopus laevis. However, cells responding to Epo in the larval liver and through the metamorphosis period under hepatic remodeling have not been characterized. In this study, tadpoles were staged using the tables of Nieuwkoop and Faber (NF). Liver cells from pre- (NF56) or post- (NF66) metamorphic stage were cultured in the presence of Epo. β2-globin mRNA expression peaked at day 7 after the start of culture. Larval β2-globin was highly expressed in NF56-derived cells, while adult β2-globinwas detected in those of NF66...
December 2016: Zoological Science
Hiromu Suga, Wataru Hirano, Toru Katoh, Kei W Matsubayashi, Haruo Katakura
The ladybird beetles Propylea quatuordecimpunctata and P. japonica have largely overlapping distributions in northern Japan, and in the laboratory produce fertile hybrids. In this study, we surveyed the distribution and morphological differentiation of these species and the hybrids in natural populations, with a focus on western Hokkaido, northern Japan. Phenotypic analyses were conducted for 987 individuals collected at 90 localities. In addition, the nuclear internal transcribed spacer-II (ITS2) region (549 bp) and part of the mitochondrial cytochrome c oxidase subunit I (COI) gene (700 bp) were sequenced for 620 individuals from 53 localities...
December 2016: Zoological Science
Hirokazu Abe, Tomohiko Kondoh, Waka Sato-Okoshi
The morphology of two Pseudopolydora species, P. cf. reticulata Radashevsky and Hsieh, 2000 and P. achaeta Radashevsky and Hsieh, 2000 are reported from Japan for the first time. Pseudopolydora cf. reticulata was collected from Japanese tidal flats, and individuals possess the characteristic netlike pigmentation on the dorsum of anterior chaetigers and the longitudinal black band along midline of caruncle. Pseudopolydora achaeta was collected from subtidal bottom mud of Onagawa Bay, and individuals have distinctive characteristics, such as intensive black pigmentation on dorsal and ventral sides of the anterior body and nearly straight vertical rows of major spines on the fifth chaetiger...
December 2016: Zoological Science
Kanako Yamao, Reiko Ishiwaka, Masaru Murakami, Seiki Takatsuki
A previous quantitative analysis of the food composition of the Eurasian harvest mouse (Micromys minutus) in Japan showed that it is insectivorous and granivorous. This supports the expectation that such a small mammal requires highly nutritious foods. Other studies have analyzed the feces of harvest mice, but these were only collected during winter in order to minimize disturbance of the animals. In the present study, we collected samples from all four seasons in order to understand changes in diet throughout the year...
December 2016: Zoological Science
Michio Imafuku, Naomichi Ogihara
There have been only a few reports on the directional reflection of light by butterfly wings. Here, we systematically investigated this phenomenon in a lycaenid butterfly, Chrysozephyrus smaragdinus,in which males have bright green wings based on structural coloration. We used a device that measures intensities of light in hemispherical space by vertical shifting of a sensor and horizontal rotation of the stage carrying the wing, which is illuminated from the top, to determine the direction of light reflected by the fore- and hindwings...
December 2016: Zoological Science
Han Yang, Chung-Ping Lin, Ai-Ping Liang
South China is a region of remarkable topographic complexity. However, the impact of climate fluctuations in the Pleistocene on the local fauna and especially insects has not been extensively studied. We integrated mitochondrial DNA (mtDNA) and microsatellite data of the rice spittle bug, Callitettix versicolor, to determine the genetic structure, potential biogeographic barriers, and historical demography of this species. The mtDNA data revealed two distinct lineages (Western and Eastern) congruent with the geographically separated western and eastern sub-regions of the Hengduan Mountains...
December 2016: Zoological Science
Mikihiko Kumashiro, Masaki Sakai
We found that the genitalia of the male cricket Gryllus bimaculatus are equipped with an autocleaning system. The cricket keeps its genitalia clean by removing foreign matter and endogenous waste. Morphological study showed that the membrane complex consists of a median pouch and a genital chamber floor covered by small scales, each of which has a base of approximately 10 µm in width and a fringe with 5-10 spines 3-20 µm in length. The scales are arranged symmetrically about the midline, curving gradually in the lateral direction and continuing to the lateral pouch serving as a trash container...
December 2016: Zoological Science
Mikihiko Kumashiro, Masaki Sakai
Three types of genital movement, their neural controls, and functional roles were investigated to gain a better understanding of the mechanism underlying autocleaning in the male cricket. The membrane complex consisting of the median pouch and genital chamber floor shows peculiar undulation that is composed of two types of movements: a right-left large shift and small crease-like movements. The large shift was caused by contraction of a pair of muscles (MPA) located anterior to the median pouch, while the crease-like movements were caused by numerous muscle fibers extending over the membrane complex...
December 2016: Zoological Science
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