Zoological Letters最新文献

{"title":"Coloration principles of the Great purple emperor butterfly (Sasakia charonda).","authors":"Doekele G Stavenga,&nbsp;Hein L Leertouwer,&nbsp;Kentaro Arikawa","doi":"10.1186/s40851-020-00164-6","DOIUrl":"https://doi.org/10.1186/s40851-020-00164-6","url":null,"abstract":"<p><p>The dorsal wings of male Sasakia charonda butterflies display a striking blue iridescent coloration, which is accentuated by white, orange-yellow and red spots, as well as by brown margins. The ventral wings also have a variegated, but more subdued, pattern. We investigated the optical basis of the various colors of intact wings as well as isolated wing scales by applying light and electron microscopy, imaging scatterometry and (micro)spectrophotometry. The prominent blue iridescence is due to scales with tightly packed, multilayered ridges that contain melanin pigment. The scales in the brown wing margins also contain melanin. Pigments extracted from the orange-yellow and red spots indicate the presence of 3-OH-kynurenine and ommochrome pigment. The scales in the white spots also have multilayered ridges but lack pigment. The lower lamina of the scales plays a so-far undervalued but often crucial role. Its thin-film properties color the majority of the ventral wing scales, which are unpigmented and have large windows. The lower lamina acting as a thin-film reflector generally contributes to the reflectance of the various scale types.</p>","PeriodicalId":54280,"journal":{"name":"Zoological Letters","volume":"6 1","pages":"13"},"PeriodicalIF":2.7,"publicationDate":"2020-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40851-020-00164-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38351097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The role of clockwork orange in the circadian clock of the cricket Gryllus bimaculatus.","authors":"Yasuaki Tomiyama,&nbsp;Tsugumichi Shinohara,&nbsp;Mirai Matsuka,&nbsp;Tetsuya Bando,&nbsp;Taro Mito,&nbsp;Kenji Tomioka","doi":"10.1186/s40851-020-00166-4","DOIUrl":"https://doi.org/10.1186/s40851-020-00166-4","url":null,"abstract":"<p><p>The circadian clock generates rhythms of approximately 24 h through periodic expression of the clock genes. In insects, the major clock genes period (per) and timeless (tim) are rhythmically expressed upon their transactivation by CLOCK/CYCLE, with peak levels in the early night. In Drosophila, clockwork orange (cwo) is known to inhibit the transcription of per and tim during the daytime to enhance the amplitude of the rhythm, but its function in other insects is largely unknown. In this study, we investigated the role of cwo in the clock mechanism of the cricket Gryllus bimaculatus. The results of quantitative RT-PCR showed that under a light/dark (LD) cycle, cwo is rhythmically expressed in the optic lobe (lamina-medulla complex) and peaks during the night. When cwo was knocked down via RNA interference (RNAi), some crickets lost their locomotor rhythm, while others maintained a rhythm but exhibited a longer free-running period under constant darkness (DD). In cwo^RNAi crickets, all clock genes except for cryptochrome 2 (cry2) showed arrhythmic expression under DD; under LD, some of the clock genes showed higher mRNA levels, and tim showed rhythmic expression with a delayed phase. Based on these results, we propose that cwo plays an important role in the cricket circadian clock.</p>","PeriodicalId":54280,"journal":{"name":"Zoological Letters","volume":"6 1","pages":"12"},"PeriodicalIF":2.7,"publicationDate":"2020-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40851-020-00166-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38689057","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Morphology of Stephanella hina (Bryozoa, Phylactolaemata): common phylactolaemate and unexpected, unique characters.","authors":"Thomas F Schwaha,&nbsp;Masato Hirose","doi":"10.1186/s40851-020-00165-5","DOIUrl":"https://doi.org/10.1186/s40851-020-00165-5","url":null,"abstract":"<p><p>Stephanella hina is a little studied freshwater bryozoan belonging to Phylactolaemata. It is currently the only representative of the family Stephanellidae, which in most reconstructions is early branching, sometimes even sister group to the remaining phylactolaemate families. The morphological and histological details of this species are entirely unknown. Consequently, the main aim of this study was to conduct a detailed morphological analysis of S. hina using histological serial sections, 3D reconstruction, immunocytochemical staining and confocal laser scanning microscopy techniques. The general morphology is reminiscent of other phylactolaemates; however, there are several, probably apomorphic, details characteristic of S. hina. The most evident difference lies in the lophophoral base, where the ganglionic horns/extensions do not follow the traverse of the lophophoral arms but bend medially inwards towards the mouth opening. Likewise, the paired forked canal does not fuse medially in the lophophoral concavity as found in all other phylactolaemates. Additional smaller differences are also found in the neuro-muscular system: the rooting of the tentacle muscle is less complex than in other phylactolaemates, the funiculus lacks longitudinal muscles, the caecum has smooth muscle fibres, latero-abfrontal tentacle nerves are not detected and the medio-frontal nerves mostly emerge directly from the circum-oral nerve ring. In the apertural area, several neurite bundles extend into the vestibular wall and probably innervate neurosecretory cells surrounding the orifice. These morphological characteristics support the distinct placement of this species in a separate family. Whether these characteristics are apomorphic or possibly shared with other phylactolaemates will require the study of the early branching Lophopodidae, which remains one of the least studied taxa to date.</p>","PeriodicalId":54280,"journal":{"name":"Zoological Letters","volume":"6 1","pages":"11"},"PeriodicalIF":2.7,"publicationDate":"2020-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40851-020-00165-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38350383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Correction to: Natural selection, selective breeding, and the evolution of resistance of honeybees (<i>Apis mellifera)</i> against <i>Varroa</i>.","authors":"Jacques J M van Alphen,&nbsp;Bart Jan Fernhout","doi":"10.1186/s40851-020-00162-8","DOIUrl":"https://doi.org/10.1186/s40851-020-00162-8","url":null,"abstract":"<p><p>[This corrects the article DOI: 10.1186/s40851-020-00158-4.].</p>","PeriodicalId":54280,"journal":{"name":"Zoological Letters","volume":"6 ","pages":"10"},"PeriodicalIF":2.7,"publicationDate":"2020-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40851-020-00162-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38053974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sea as a color palette: the ecology and evolution of fluorescence.","authors":"Marie-Lyne Macel,&nbsp;Filomena Ristoratore,&nbsp;Annamaria Locascio,&nbsp;Antonietta Spagnuolo,&nbsp;Paolo Sordino,&nbsp;Salvatore D'Aniello","doi":"10.1186/s40851-020-00161-9","DOIUrl":"https://doi.org/10.1186/s40851-020-00161-9","url":null,"abstract":"<p><p>Fluorescence and luminescence are widespread optical phenomena exhibited by organisms living in terrestrial and aquatic environments. While many underlying mechanistic features have been identified and characterized at the molecular and cellular levels, much less is known about the ecology and evolution of these forms of bioluminescence. In this review, we summarize recent findings in the evolutionary history and ecological functions of fluorescent proteins (FP) and pigments. Evidence for green fluorescent protein (GFP) orthologs in cephalochordates and non-GFP fluorescent proteins in vertebrates suggests unexplored evolutionary scenarios that favor multiple independent origins of fluorescence across metazoan lineages. Several context-dependent behavioral and physiological roles have been attributed to fluorescent proteins, ranging from communication and predation to UV protection. However, rigorous functional and mechanistic studies are needed to shed light on the ecological functions and control mechanisms of fluorescence.</p>","PeriodicalId":54280,"journal":{"name":"Zoological Letters","volume":"6 ","pages":"9"},"PeriodicalIF":2.7,"publicationDate":"2020-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40851-020-00161-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38043321","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structural and bio-functional assessment of the postaxillary gland in <i>Nidirana pleuraden</i> (Amphibia: Anura: Ranidae).","authors":"Yuzhou Gong, Yiwei Zeng, Puyang Zheng, Xun Liao, Feng Xie","doi":"10.1186/s40851-020-00160-w","DOIUrl":"10.1186/s40851-020-00160-w","url":null,"abstract":"<p><strong>Background: </strong>Owing to their incomplete adaptation to the terrestrial environment, amphibians possess complex cutaneous glandular systems. The skin glands not only regulate water loss and respiratory gas and salt exchange, but are also involved in defense against predators and microorganisms, social communication, and reproduction. These glands are distributed throughout the integument, but can accumulate in specific regions, forming visible outgrowths known as macroglands. Some macroglands are sexually dimorphic and mediate intersexual communication and reproductive success. The postaxillary gland is a sexually dimorphic macrogland in <i>Nidirana pleuraden</i>. Its biological function and its morphological and histochemical characteristics are unclear. In the present study, we describe the structure and ultrastructure of the postaxillary gland, and explore its main function.</p><p><strong>Results: </strong>The postaxillary gland has a thinner epidermis than the dorsal region of <i>N. pleuraden</i>. In addition to ordinary serous glands (OSG), type I and II mucous gland (I MG & II MG), a type of specialized mucous gland (SMG) is also found to constitute the postaxillary gland. The SMG is larger than other gland types, and consists of high columnar mucocytes with basal nuclei arranged radially toward a lumen. SMGs are positive to periodic acid-Schiff stain and stained blue in Masson's trichrome stain. A discontinuous myoepithelial sheath lacking innervation encircles SMG mucocytes, and the outlets of such glands are X- or Y-shaped. Transmission electron microscopy reveals abundant secretory granules in SMG, which are biphasic, composed of an electron-opaque outer ring and a less electron-dense core. Lipid droplets, and organelles, such as rough endoplasmic reticulum and Golgi stacks, are located in the supranuclear cytoplasm of the mucocytes in SMG. Female <i>N. pleuraden</i> exhibits chemotaxis toward homogenate of the postaxillary gland, but male does not. On treatment with trypsin, this sexual attraction disappears.</p><p><strong>Conclusions: </strong>The postaxillary gland of <i>N. pleuraden</i> is a male-specific macrogland that consists primarily of SMGs, together with OSGs, I MGs and II MGs. Other than their extremely large size, SMGs structurally and histochemically resemble many reported specialized gland types in amphibian sexually dimorphic skin glands. Secretions of the postaxillary gland are proteinaceous sexual pheromones, which are believed to attract females at male calling intermissions.</p>","PeriodicalId":54280,"journal":{"name":"Zoological Letters","volume":"6 ","pages":"7"},"PeriodicalIF":2.7,"publicationDate":"2020-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7275488/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38027466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evidence from ileum and liver transcriptomes of resistance to high-salt and water-deprivation conditions in camel.","authors":"Dong Zhang,&nbsp;Jing Pan,&nbsp;Huanmin Zhou,&nbsp;Yu Cao","doi":"10.1186/s40851-020-00159-3","DOIUrl":"https://doi.org/10.1186/s40851-020-00159-3","url":null,"abstract":"<p><p>Camels have evolved various resistance characteristics adaptive to their desert habitats. In the present study, we used high-throughput sequencing to investigate stress-induced alternative splicing events as well as different genes involved in resistance to water deprivation and salt absorption in the ileum and liver in <i>Camelus bactrianus</i>. Through association analyses of mRNA, miRNA and lncRNA, we sought to explicate how camels respond to high salt and water scarcity conditions. There were two modes by which genes driven by alternative splicing were enriched to molecular functions, invoking of which was potentially fixed by organ and stress types. With qRT-PCR detection, the differentially expressed <i>MUC6</i>, <i>AQP5</i>, <i>LOC105076960</i>, <i>PKP4</i>, <i>CDH11</i>, <i>TENM1, SDS</i>, <i>LOC105061856</i>, <i>PLIN2</i> and <i>UPP2</i> were screened as functionally important genes, along with miR-29b, miR-484, miR-362-5p, miR-96, miR-195, miR-128 and miR-148a. These genes contributed to cellular stress resistance, for instance by reducing water loss, inhibiting excessive import of sodium, improving protective barriers and sodium ion homeostasis, and maintaining uridine content. The underlying competing endogenous RNAs referred to LNC001664, let-7e and <i>LOC105076960</i> mRNA in ileum, and LNC001438, LNC003417, LNC001770, miR-199c and <i>TENM1</i> mRNA in liver. Besides competent interpretation to resistance, there may be inspirations for curing human diseases triggered by high-salt intake.</p>","PeriodicalId":54280,"journal":{"name":"Zoological Letters","volume":"6 ","pages":"8"},"PeriodicalIF":2.7,"publicationDate":"2020-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40851-020-00159-3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38027467","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Natural selection, selective breeding, and the evolution of resistance of honeybees (<i>Apis mellifera)</i> against <i>Varroa</i>.","authors":"Jacques J M van Alphen,&nbsp;Bart Jan Fernhout","doi":"10.1186/s40851-020-00158-4","DOIUrl":"https://doi.org/10.1186/s40851-020-00158-4","url":null,"abstract":"<p><p>We examine evidence for natural selection resulting in <i>Apis mellifera</i> becoming tolerant or resistant to <i>Varroa</i> mites in different bee populations. We discuss traits implicated in <i>Varroa</i> resistance and how they can be measured. We show that some of the measurements used are ambiguous, as they measure a combination of traits. In addition to behavioural traits, such as removal of infested pupae, grooming to remove mites from bees or larval odours, small colony size, frequent swarming, and smaller brood cell size may also help to reduce reproductive rates of <i>Varroa</i>. Finally, bees may be tolerant of high <i>Varroa</i> infections when they are resistant or tolerant to viruses implicated in colony collapse. We provide evidence that honeybees are an extremely outbreeding species. Mating structure is important for how natural selection operates. Evidence for successful natural selection of resistance traits against <i>Varroa</i> comes from South Africa and from Africanized honeybees in South America. Initially, <i>Varroa</i> was present in high densities and killed about 30% of the colonies, but soon after its spread, numbers per hive decreased and colonies survived without treatment. This shows that natural selection can result in resistance in large panmictic populations when a large proportion of the population survives the initial <i>Varroa</i> invasion. Natural selection in Europe and North America has not resulted in large-scale resistance. Upon arrival of <i>Varroa</i>, the frequency of traits to counter mites and associated viruses in European honey bees was low. This forced beekeepers to protect bees by chemical treatment, hampering natural selection. In a Swedish experiment on natural selection in an isolated mating population, only 7% of the colonies survived, resulting in strong inbreeding. Other experiments with untreated, surviving colonies failed because outbreeding counteracted the effects of selection. If loss of genetic variation is prevented, colony level selection in closed mating populations can proceed more easily, as natural selection is not counteracted by the dispersal of resistance genes. In large panmictic populations, selective breeding can be used to increase the level of resistance to a threshold level at which natural selection can be expected to take over.</p>","PeriodicalId":54280,"journal":{"name":"Zoological Letters","volume":"6 ","pages":"6"},"PeriodicalIF":2.7,"publicationDate":"2020-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40851-020-00158-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"37984379","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cellular and molecular aspects of oocyte maturation and fertilization: a perspective from the actin cytoskeleton.","authors":"Luigia Santella, Nunzia Limatola, Jong Tai Chun","doi":"10.1186/s40851-020-00157-5","DOIUrl":"10.1186/s40851-020-00157-5","url":null,"abstract":"<p><strong>Abstract: </strong>Much of the scientific knowledge on oocyte maturation, fertilization, and embryonic development has come from the experiments using gametes of marine organisms that reproduce by external fertilization. In particular, echinoderm eggs have enabled the study of structural and biochemical changes related to meiotic maturation and fertilization owing to the abundant availability of large and transparent oocytes and eggs. Thus, in vitro studies of oocyte maturation and sperm-induced egg activation in starfish are carried out under experimental conditions that resemble those occurring in nature. During the maturation process, immature oocytes of starfish are released from the prophase of the first meiotic division, and acquire the competence to be fertilized through a highly programmed sequence of morphological and physiological changes at the oocyte surface. In addition, the changes in the cortical and nuclear regions are essential for normal and monospermic fertilization. This review summarizes the current state of research on the cortical actin cytoskeleton in mediating structural and physiological changes during oocyte maturation and sperm and egg activation in starfish and sea urchin. The common denominator in these studies with echinoderms is that exquisite rearrangements of the egg cortical actin filaments play pivotal roles in gamete interactions, Ca²⁺ signaling, exocytosis of cortical granules, and control of monospermic fertilization. In this review, we also compare findings from studies using invertebrate eggs with what is known about the contributions made by the actin cytoskeleton in mammalian eggs. Since the cortical actin cytoskeleton affects microvillar morphology, movement, and positioning of organelles and vesicles, and the topography of the egg surface, these changes have impacts on the fertilization process, as has been suggested by recent morphological studies on starfish oocytes and eggs using scanning electron microscopy. Drawing the parallelism between vitelline layer of echinoderm eggs and the zona pellucida of mammalian eggs, we also discuss the importance of the egg surface in mediating monospermic fertilization.</p><p><strong>Graphical abstract: </strong></p>","PeriodicalId":54280,"journal":{"name":"Zoological Letters","volume":"6 ","pages":"5"},"PeriodicalIF":1.7,"publicationDate":"2020-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7158055/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"37855355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"First observation of larval oarfish, <i>Regalecus russelii</i>, from fertilized eggs through hatching, following artificial insemination in captivity.","authors":"Shin-Ichiro Oka,&nbsp;Masaru Nakamura,&nbsp;Ryo Nozu,&nbsp;Kei Miyamoto","doi":"10.1186/s40851-020-00156-6","DOIUrl":"https://doi.org/10.1186/s40851-020-00156-6","url":null,"abstract":"<p><strong>Background: </strong>Little is known about the life history of oarfish of the genus <i>Regalecus</i>, although it is a famous deep-sea fish and an apparent origin of sea serpent legends. We successfully performed artificial insemination using a recently dead pair of sexually mature individuals. We report for the first time development from fertilized eggs to early larvae in the Lampridiformes.</p><p><strong>Results: </strong>Eggs required 18 days of development from fertilization to hatching under 20.5-22.5 °C conditions. Oarfish larvae had similar morphological features as other lampridiform larvae hatched in the ocean. Larvae typically faced downward and swam using pectoral fins; they frequently opened their mouths. This mouth-opening behavior and swimming ability were both consistent with osteological development. The larvae did not eat and died four days after hatching.</p><p><strong>Conclusions: </strong>This is the first successful instance of artificial insemination and hatching in the oarfish, as well as the first reliable morphological and behavioral description of lampridiform larvae.</p>","PeriodicalId":54280,"journal":{"name":"Zoological Letters","volume":"6 ","pages":"4"},"PeriodicalIF":2.7,"publicationDate":"2020-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40851-020-00156-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"37837099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}