Researcher Profile and Settings

Master

Affiliation (Master)

• Research Faculty of Agriculture　Fundamental AgriScience Research　Agrobiology and Bioresources

Affiliation (Master)

• Research Faculty of Agriculture　Fundamental AgriScience Research　Agrobiology and Bioresources

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Profile and Settings

Affiliation

• Systematic Entomology, Graduate School of Agriculture, Hokkaido University

Profile and Settings

• Name (Japanese)

  Matsumura

• Name (Kana)

  Yoko

• Name

  202201020399580473

Affiliation

• Systematic Entomology, Graduate School of Agriculture, Hokkaido University

Achievement

Research Areas

• Life sciences / Biodiversity and systematics

Research Experience

• 2022/05 - Today 北海道大学 農学研究院
• 2021/06 - 2022/04 University of Greifswald
• 2014/06 - 2021/04 Kiel University
• 2015/04 - 2016/12 Keio University
• 2012/06 - 2014/05 Jena University
• 2012/04 - 2012/05 北海道大学 農学研究院 訪問研究員

Education

• 2009/04 - 2012/03  北海道大学 農学院 環境資源学（博士課程）
• 2007/04 - 2009/03  北海道大学 農学院 環境資源学（修士課程）
• 2003/04 - 2007/03  富山大学 理学部 生物学科（学士過程）

Published Papers

• A new species of Zoraptera, Zorotypus komatsui sp. nov. from Cameroon and a redescription of Zorotypus vinsoni Paulian, 1951 (Polyneoptera, Zoraptera)

  Yoko Matsumura, Munetoshi Maruyama, Nelson N. Ntonifor, Rolf G. Beutel

  ZooKeys 1178 39 - 59 1313-2989 2023/09/01 [Refereed][Not invited]
   

  A new species of the order Zoraptera, Zorotypus komatsui Matsumura, Maruyama, Ntonifor & Beutel, sp. nov., is described from Cameroon. The female and male morphology of another species, Z. vinsoni, is re-described, and its new distribution in Madagascar is recorded. A particular focus is on the male postabdominal morphology. This is apparently a crucial body region in the very small order with an extreme variation of the genital apparatus but otherwise a very uniform morphology. The male of the newly described species shares rudimentary male genitalia and well-developed postabdominal projections with the distantly related Spermozoros impolitus, apparently a result of parallel evolution. Whether males of Z. komatsui also perform external sperm transfer like S. impolitus remains to be shown. The collecting of the material used for this study suggests that the present knowledge of zorapteran species diversity of the Afrotropical region is very fragmentary.
• The tight attachment achieved by the male discoidal setae is possibly a counter-adaptation to the grease layer on female integument surfaces in green dock beetles

  Yoko Matsumura, Elena V. Gorb, Stanislav N. Gorb

  Journal of The Royal Society Interface 20 (205) 2023/08/16 [Refereed][Not invited]
   

  Green dock beetles Gastrophysa viridula exhibit sexual dimorphism in tarsal attachment setae: females have only pointed, lanceolate and spatula-like setae, while males additionally possess discoidal ones. The sexual dimorphism is probably attributed to the necessity of male discoidal setae to adhere to the smooth back of the female during copulation. We aimed to understand its possible mechanism of attachment with G. viridula . Pull-off forces of both females and males were measured on (i) alive females, (ii) dead and dried females, and (iii) resin replicas of fresh females. The attachment ability tended to increase on dead and replicated female surfaces in both sexes, which indicates that the epicuticular grease layer on the integument of alive intact beetles decreases the attachment. This tendency was prominent in females. The present study clearly showed that in G. viridula discoidal setae enable the males to adhere stronger to female surfaces. The divergent performance found between the sexes differing in their setal composition is probably caused by the stiffness difference between the setae types and by the specific shape of the setal tips. A peculiar reproductive biology in G. viridula is probably attributed to this remarkable divergence of labour in their attachment pads between the sexes.
• Material gradients in gastropod radulae and their biomechanical significance: a combined approach on the paludomid Lavigeria grandis

  Wencke Krings, Yoko Matsumura, Jan-Ole Brü, Stanislav N. Gorb

  The Science of Nature 109 (6) 0028-1042 2022/11/02 [Refereed][Not invited]
   

  Abstract The radula, a chitinous membrane spiked with teeth, is the molluscan autapomorphy for the gathering and processing of food. The teeth, as actual interfaces between the organism and the ingesta, act as load transmitting regions and have to withstand high stresses during foraging — without structural failure or high degrees of wear. Mechanisms contributing to this were studied previously in paludomid gastropods from Lake Tanganyika. For some species, gradients in hardness and Young’s modulus along the teeth were detected, enabling the bending and relying of teeth onto the next row, distributing the stresses more equally. The here presented study on one of them — Lavigeria grandis — aims at shedding light on the origin of these functional gradients. The mechanical properties were identified by nanoindentation technique and compared to the elemental composition, determined by elemental dispersive X-ray spectroscopy (EDX, EDS). This was done for the complete radular (mature and immature tooth rows), resulting in overall 236 EDX and 700 nanoindentation measurements. Even though teeth showed regional differences in elemental composition, we could not correlate the mechanical gradients with the elemental proportions. By applying confocal laser scanning microscopy (CLSM), we were finally able to relate the mechanical properties with the degree of tanning. CLSM is a common technique used on arthropod cuticle, but was never applied on radular teeth before. In general, we found that nanoindentation and CLSM techniques complement one another, as for example, CLSM is capable of revealing heterogeneities in material or micro-gradients, which leads to a better understanding of the functionalities of biological materials and structures.
• Distal leg structures of Zoraptera – did the loss of adhesive devices curb the chance of diversification?

  Yoko Matsumura, Sheila P. Lima, José A. Rafael, Josenir T. Câmara, Rolf G. Beutel, Stanislav N. Gorb

  Arthropod Structure & Development 68 101164 - 101164 1467-8039 2022/05 [Refereed][Not invited]
  
• Random or handedness? Use of laterally paired penises in Nala earwigs (Insecta: Dermaptera: Labiduridae)

  Yoshitaka Kamimura, Yoko Matsumura, Chin-Cheng Scotty Yang, Stanislav N Gorb

  Biological Journal of the Linnean Society 134 (3) 716 - 731 0024-4066 2021/10/22 [Refereed][Not invited]
   

  Abstract Animals can show bias in their use of laterally paired organs that do not have any conspicuous anatomical differentiation between the right and left organs. Like right handedness in humans, males of the giant earwig Labidura riparia (Labiduridae: Labidurinae) preferentially (~90%) use the right one of their laterally paired penises for copulation. To elucidate the evolutionary origin of this lateralization, patterns of penis use were examined for the related species of the genus Nala (Labiduridae: Nalinae). In multiple populations and broods of both Nala lividipes and Nala nepalensis, males that were ready to use the right or left penis were equally frequent, providing a striking contrast to Labidura. Surgical ablation of one of the two penises revealed that both penises are functionally competent in N. lividipes. Nevertheless, each male almost consistently used only one of the paired penises, either the right or the left one. Changes in penis use were estimated to occur only once per 64–143 days per male. The present study is the first report of individual-level lateralization for animal genitalia that do not show any conspicuous anatomical differentiation between the right and left organs. Possible advantages of lateralization are discussed in relationship to co-evolution of the genitalia between the sexes.
• Mechanical properties of a female reproductive tract of a beetle and implications for penile penetration.

  Yoko Matsumura, Alexander Kovalev, Stanislav N Gorb

  Proceedings. Biological sciences 288 (1954) 20211125 - 20211125 2021/07/14 [Refereed][Not invited]
   

  Coevolution of male and female genitalia is widespread in animals. Nevertheless, few studies have examined the mechanics of genital interactions during mating. We characterized the mechanical properties of the elongated female genitalia, the spermathecal duct, of the small cassidine beetle, Cassida rubiginosa. The data were compared with the mechanical properties of the elongated male genitalia, the flagellum. We analysed the material distributions of the spermathecal duct using a microscopy technique, established a tensile test setup under a light microscope and conducted tensile tests. Diameter and tensile stiffness gradients were present along the spermathecal duct, but its Young's modulus and material distribution were more or less homogeneous. The results confirmed the hypothesis based on numerical simulations that the spermathecal duct is more rigid than the flagellum. In the study species, the penile penetration force is simply applied to the base of the hyper-elongated flagellum and conveyed along the flagellum to its tip. Considering this simple penetration mechanism, the relatively low flexibility of the spermathecal duct, compared to the flagellum, is likely to be essential for effective penetration of the flagellum.
• Excavation mechanics of the elongated female rostrum of the acorn weevil Curculio glandium (Coleoptera; Curculionidae)

  Yoko Matsumura, Mohsen Jafarpour, Michał Reut, Bardiya Shams Moattar, Abolfazl Darvizeh, Stanislav N. Gorb, Hamed Rajabi

  Applied Physics A 127 (5) 0947-8396 2021/05 [Refereed][Not invited]
   

  Abstract Elongated rostra (snouts) are remarkable features of many female weevils. The female of Curculio glandium uses the snout to excavate channels in acorns to oviposit. Considering the slenderness of the rostrum, the excavation of channels in solid substrates without buckling is a challenging task from both engineering and biological points of view. Here we aimed to examine the roles of the material properties and morphology of the rostrum in its buckling resistance. We employed microscopy techniques, non-destructive material characterisation and finite element (FE) modelling to shed more light on the excavation mechanics of the rostrum. We found that sexual dimorphisms are present not only in the length but also in the material, particularly the elastic modulus, and morphological features, particularly the curvature and thickness of the cuticular layers. Our FE modelling showed that those factors play essential roles to maximise the buckling resistance and minimise the bending resistance of the female rostrum. Considering that during excavation, the rostrum needs to be straightened without buckling, the functionality of the rostrum is likely to be a compromise between the flexibility and stiffness.
• Penetration mechanics of elongated female and male genitalia of earwigs

  Yoko Matsumura, Yoshitaka Kamimura, Chow-Yang Lee, Stanislav N. Gorb, Hamed Rajabi

  SCIENTIFIC REPORTS 11 (1) 7920 - 7920 2045-2322 2021/04 [Refereed][Not invited]
   

  We unveiled the penile penetration mechanics of two earwig species, Echinosoma horridum, whose intromittent organ, termed virga, is extraordinarily long, and E. denticulatum, whose virga is conversely short. We characterised configuration, geometry, material and bending stiffness for both virga and spermatheca. The short virga of E. denticulatum has a material gradient with the stiffer base, whereas the long virga of E. horridum and the spermathecae of both species are homogeneously sclerotised. The long virga of E. horridum has a lower bending stiffness than the spermatheca. The virga of E. denticulatum is overall less flexible than the spermatheca. We compared our results to a previous study on the penetration mechanics of elongated beetle genitalia. Based on the comparison, we hypothesised that the lower stiffness of the male intromittent organ comparing to the corresponding female structure is a universal prerequisite for the penetration mechanics of the elongated intromittent organ in insects.
• Material heterogeneity of male genitalia reduces genital damage in a bushcricket during sperm removal behaviour.

  Yoko Matsumura, Mohsen Jafarpour, Steven A Ramm, Klaus Reinhold, Stanislav N Gorb, Hamed Rajabi

  Die Naturwissenschaften 107 (6) 52 - 52 2020/11/25 [Refereed][Not invited]
   

  Sperm removal behaviour (SRB) is known in many animals, and male genital structures are often involved in the SRB, e.g. rubbing female genitalia vigorously. However, it remains unclear how those male genital structures function properly without severe genital damage during SRB. In the present study, we focused on the bushcricket Metaplastes ornatus and examined the biomechanics of male and female genital structures, involved in their SRB as a model case. During an initial phase of mating, males of this species thrust their subgenital plate with hook-like spurs and many microscopic spines into the female genital chamber. By moving the subgenital plate back-and-forth, males stimulate females, and this stimulation induces the ejection of sperm previously stored in females. We aimed to uncover the mechanics of the interaction between the subgenital plate and genital chamber during SRB. The genital morphology and its material composition were investigated using modern imaging and microscopy techniques. The obtained results showed a pronounced material heterogeneity in the subgenital plate and the genital chamber. The material heterogeneity was completely absent in that of a second bushcricket species, Poecilimon veluchianus, which does not exhibit SRB. Finite element simulations showed that the specific material heterogeneity can redistribute the stress in the subgenital plate of M. ornatus and, thereby, reduces stress concentration during SRB. This may explain why only a few examined males had a broken spur. We suggest that the observed structural features and material heterogeneity in M. ornatus are adaptations to their SRB.
• Variation of attachment ability of Nezara viridula (Hemiptera: Pentatomidae) during nymphal development and adult aging

  Gianandrea Salerno, Manuela Rebora, Silvana Piersanti, Yoko Matsumura, Elena Gorb, Stanislav Gorb

  JOURNAL OF INSECT PHYSIOLOGY 127 0022-1910 2020/11 [Refereed][Not invited]
   

  The present investigation reports data on the attachment ability of the Southern green stink bug Nezara viridula (Hemiptera: Pentatomidae), a relevant pest in the world, along its whole life cycle. Using a centrifugal force tester, we evaluated a) the differences in the attachment ability among the four active nymphal developmental instars (N2-N5 nymphs) and adult to hydrophilic glass, showing an increased attachment ability during ontogenesis, owing to increased pulvilli size and efficiency; b) the possible role of growth and body shape on insect attachment ability on hydrophilic glass during the intermoult period, revealing that N. viridula nymphs attach stronger (higher safety factor) in the first part of the intermoult period; c) the age-specific differences in the attachment ability of adults of both sexes on hydrophilic glass, showing the best performance at an intermediate age, in agreement with a higher proportion of resilin in comparison with younger or older insects; d) the difference in attachment ability on hydrophilic vs. hydrophobic glass along the insect development, revealing a strong effect of surface hydrophobicity on reducing the attachment of N. viridula nymphs and adults.The results on the attachment ability of a hemimetabolous insect along its life cycle are relevant because they 1) shed light on different adaptations of attachment pads in relation to insect size, shape and age; 2) deepen the knowledge on the functional morphological adaptations, thus potentially contributing to the development of suitable control systems for this important pest insect.
• Resilin Distribution and Sexual Dimorphism in the Midge Antenna and Their Influence on Frequency Sensitivity

  Brian D. Saltin, Yoko Matsumura, Andrew Reid, James F. Windmill, Stanislav N. Gorb, Joseph C. Jackson

  INSECTS 11 (8) 2020/08 [Refereed][Not invited]
   

  Simple Summary The antennae of insects are multipurpose sensory organs that can detect chemicals, gravity, vibrations, and sound, among others. While such sensors are very specialized and adapted to their specific needs, the way the antenna itself is built has often been considered either uninteresting or unimportant. We used a laser to scan the antenna of the midgeChironomus riparius. Insect cuticle, if illuminated with laser light, reflects autofluorescent light, an emission that has long been known to indicate the material properties of the scanned cuticle sample. Rather than a simple beam-like structure of constant material stiffness, we saw bands of hard and soft material, distributed along the length of the antenna. We were able to computer-simulate the effect of this banded structure on the antenna's resonant frequency and showed that it allows the beam to vibrate at different frequencies than would be expected only by its shape. This discovery will help us to better understand these animals' biology and can inspire future biomimetic sensors for detecting sound or vibration. Small-scale bioacoustic sensors, such as antennae in insects, are often considered, biomechanically, to be not much more than the sum of their basic geometric features. Therefore, little is known about the fine structure and material properties of these sensors-even less so about the degree to which the well-known sexual dimorphism of the insect antenna structure affects those properties. By using confocal laser scanning microscopy (CLSM), we determined material composition patterns and estimated distribution of stiffer and softer materials in the antennae of males and females of the non-biting midgeChironomus riparius. Using finite element modelling (FEM), we also have evidence that the differences in composition of these antennae can influence their mechanical responses. This study points to the possibility that modulating the elastic and viscoelastic properties along the length of the antennae can affect resonant characteristics beyond those expected of simple mass-on-a-spring systems-in this case, a simple banded structure can change the antennal frequency sensitivity. This constitutes a simple principle that, now demonstrated in another Dipteran group, could be widespread in insects to improve various passive and active sensory performances.
• Distal leg structures of the Aculeata (Hymenoptera): A comparative evolutionary study of Sceliphron (Sphecidae) and Formica (Formicidae)

  Rolf Georg Beutel, Adrian Richter, Roberto A. Keller, Francisco Hita Garcia, Yoko Matsumura, Evan P. Economo, Stanislav N. Gorb

  Journal of Morphology 281 (7) 737 - 753 0362-2525 2020/07 [Refereed][Not invited]
  
• 3D printed spermathecae as experimental models to understand sperm dynamics in leaf beetles

  Yoko Matsumura, Sinje Guerke, Halvor T. Tramsen, Stanislav N. Gorb

  BMC ZOOLOGY 5 (1) 2020/07 [Refereed][Not invited]
   

  Background Postcopulatory mate choice occurs ubiquitously in the animal kingdom. However, it is usually a major challenge to visualise the process taking place in a body. This fact makes it difficult to understand the mechanisms of the process. By focusing on the shape of female sperm storage organs (spermathecae), we aimed to elucidate their functional morphology using six representative beetle species and to simulate sperm dynamics in artificial spermathecae with different structural features. Results Morphology and material gradients were studied using micro-computed tomography (mu CT) and confocal laser scanning microscopy. This study shows a diversity of external and internal structures of the spermathecae among species. Despite the diversity, all species possess a common pumping region, which is composed of a sclerotised chamber, muscles and a resilin-enriched region. By focusing on the speciesAgelastica alni, whose spermatheca is relatively simple in shape with an internal protuberance, we simulated sperm dynamics by establishing a fabrication method to create enlarged, transparent, flexible and low-cost 3D models of biological structures based on mu CT data. This experiment shows that the internal protuberance in the species functions as an efficient mixing device of stored sperm. Conclusions The observed spermathecal musculature implies that the sclerotised chamber of the spermatheca with muscles works as a pumping organ. Our fluid dynamics tests based on 3D printed spermathecae show that a tiny structural difference causes entirely different fluid dynamics in the spermatheca models. This result suggests that structural variations of the spermatheca strongly affect sperm dynamics. However, fluid dynamics tests still require essential measurements including sperm viscosity and the velocity of pumping cycles of the spermatheca.
• The evolution of Zoraptera

  Yoko Matsumura, Rolf G. Beutel, Jose A. Rafael, Izumi Yao, Josenir T. Camara, Sheila P. Lima, Kazunori Yoshizawa

  SYSTEMATIC ENTOMOLOGY 45 (2) 349 - 364 0307-6970 2020/04 [Refereed][Not invited]
   

  Zoraptera is one of the most enigmatic and least understood orders in insects. Based on a wide taxon sampling from all continents where the group is known, we applied a phylogenetic approach using multiple DNA sequences to elucidate species-level relationships. The resulting phylogeny shows that Zoraptera is divided into three major clades, and that two comprise species distributed on different continents. The monophyly of these clades is at least partly supported by shared derived morphological features. The divergence age estimation and ancestral distribution area reconstruction suggest an ancient origin and early radiation initiated in the Permian. Plate tectonics theory suggests that the present distribution of Zoraptera was mainly established by vicariance, rather than dispersal. The three major clades probably originated on the Pangaea supercontinent, or alternatively on the linked Gondwana and Laurasia supercontinents. Their ancient origin explains previously found conspicuous interspecific variation of the genital apparatus, sperm structure and mating behaviour, in striking contrast to a highly conserved general body morphology. We compiled data of available reproductive features and reconstructed the character evolution. Our analyses revealed repeated acquisitions and/or losses of a hyperelongated intromittent organ, mating hooks and tergal protuberances.
• Sperm transfer through hypere-longated beetle penises - morphology and theoretical approaches

  Yoko Matsumura, Jan Michels, Hamed Rajabi, Tateo Shimozawa, Stanislav N. Gorb

  SCIENTIFIC REPORTS 9 (1) 10238 - 10238 2045-2322 2019/07 [Refereed][Not invited]
   

  Many insects possess a hyper-elongated intromittent organ with a diameter of only a few micrometers. Using morphological and theoretical approaches, we investigated the biomechanics of sperm transfer through such organs by calculating (1) how far and how fast sperm could fill in the penis by capillary action, (2) how much capillary pressure is generated in the penis, and (3) how much pressure is needed to pump sperm out of the penis. The results enabled us to propose the following hypotheses: (1) penile filling basically occurs by capillary action, and (2) sperm transport to females occurs by contracting the sperm pump muscles or by active propulsion of spermatozoa. Potential experimental approaches to test these hypotheses are discussed.
• Material stiffness variation in mosquito antennae

  B. D. Saltin, Y. Matsumura, A. Reid, J. F. Windmill, S. N. Gorb, J. C. Jackson

  Journal of The Royal Society Interface 16 (154) 20190049 - 20190049 1742-5689 2019/05 [Refereed][Not invited]
   

  The antennae of mosquitoes are model systems for acoustic sensation, in that they obey general principles for sound detection, using both active feedback mechanisms and passive structural adaptations. However, the biomechanical aspect of the antennal structure is much less understood than the mechano-electrical transduction. Using confocal laser scanning microscopy, we measured the fluorescent properties of the antennae of two species of mosquito—Toxorhynchites brevipalpisandAnopheles arabiensis—and, noting that fluorescence is correlated with material stiffness, we found that the structure of the antenna is not a simple beam of homogeneous material, but is in fact a rather more complex structure with spatially distributed discrete changes in material properties. These present as bands or rings of different material in each subunit of the antenna, which repeat along its length. While these structures may simply be required for structural robustness of the antennae, we found that in FEM simulation, these banded structures can strongly affect the resonant frequencies of cantilever-beam systems, and therefore taken together our results suggest that modulating the material properties along the length of the antenna could constitute an additional mechanism for resonant tuning in these species.
• Stiffness gradients facilitate ovipositor bending and spatial probing control in a parasitic wasp

  Uros Cerkvenik, Johan L. van Leeuwen, Alexander Kovalev, Stanislav N. Gorb, Yoko Matsumura, Sander W. S. Gussekloo

  JOURNAL OF EXPERIMENTAL BIOLOGY 222 (9) 0022-0949 2019/05 [Refereed][Not invited]
   

  Many parasitic wasps use slender and steerable ovipositors to lay eggs in hosts hidden in substrates, but it is currently unknown how steering is achieved. The ovipositors generally consist of three longitudinally connected elements, one dorsal and two ventral valves that can slide along each other. For the parasitic wasp Diachasmimorpha longicaudata, it has been shown that protraction of the ventral valves causes incurving of the ventral valves towards the dorsal one, which results in a change in probing direction. We hypothesize that this shape change is due to differences in bending stiffness along the ovipositor. Alignment of the stiff tip of the dorsal valve with a more flexible ventral S-shaped region situated just behind the tip straightens this S-bend and results in upwards rotation of the ventral tip. We show that the S-shaped region of the ventral valves has a low bending stiffness because it contains soft materials such as resilin. In contrast, the large cross-sectional area of the dorsal valve tip area probably results in a high bending stiffness. Elsewhere, the dorsal valve is less stiff than the ventral valves. Our results support the hypothesis that the interaction between the stiff dorsal valve portion and the more flexible S-shaped region co-determines the configurational tip changes required for steering the ovipositor in any desired direction along curved paths in the substrate. This provides novel insights in the understanding of steering mechanisms of the hymenopteran ovipositor, and for application in man-made probes.
• Bizarre mating in the entimine weevil Polydrusus picus

  Michal Reut, Yoko Matsumura, Marek W. Kozlowski, Rolf Georg Beutel

  JOURNAL OF ZOOLOGICAL SYSTEMATICS AND EVOLUTIONARY RESEARCH 56 (2) 192 - 195 0947-5745 2018/05 [Refereed][Not invited]
   

  We report and document a new and bizarre case of the male-above position in the entimine weevil Polydrusus picus. Based on field and laboratory observations, video-recording of mating behavior, instant fixation of couples, and morphological studies, we found that males insert their endophallus deeply into the female vagina, withdraw the female ovipositor and vagina out of the female body, and keep the posture more than 20min. A possible interpretation is that the unique mating position has evolved to increase the control over mating by the males. From the female side, it could be regarded as a compromising strategy against unwanted copulations.
• A remarkable new species of Zoraptera, Zorotypus asymmetristernum sp. n., from Kenya (Insecta, Zoraptera, Zorotypidae)

  YUTA MASHIMO, YOKO MATSUMURA, ROLF G. BEUTEL, LABAN NJOROGE, RYUICHIRO MACHIDA

  Zootaxa 4388 (3) 407 - 407 1175-5326 2018/03/04 [Refereed][Not invited]
   

  A new species of order Zoraptera, Zorotypus asymmetristernum Mashimo, n. sp., is described from Kakamega, Kenya, with its major diagnostic features and characteristics of the egg described and illustrated. The new species represents the sixth zorapteran species from the Afrotropic ecozone. A brief discussion on vestigial eye spots of apteron individuals and a key to the species of the Afrotropic ecozone are provided.
• フィールドでの昆虫研究 (6) ケニア共和国へ愛しの虫を追いかけて.

  松村洋子, ンジョロゲ ラーバン, 丸山宗利, 二見恭子

  昆蟲. ニューシリーズ 21 (2) 125 - 141 2018 [Not refereed][Invited]
  
• Penetration mechanics of a beetle intromittent organ with bending stiffness gradient and a soft tip

  Yoko Matsumura, Alexander E. Kovalev, Stanislav N. Gorb

  SCIENCE ADVANCES 3 (12) eaao5469  2375-2548 2017/12 [Refereed][Not invited]
   

  Hyper-elongated structures and their penetration are widespread among insects, for example, intromittent organs, ovipositors, and piercing-sucking mouthparts. The penetration of thin structures with high aspect ratio without buckling and rupturing is mechanically very challenging. However, this problem is economically solved in nature, and the solutions might be helpful for, for example, in the development of harmless catheters. We focus on the penetration process of a hyper-elongated structure of a cassidine beetle intromittent organ, termed a flagellum. We applied a three-point bending test for the flagellum to measure its bending stiffness along the entire flagellum. We demonstrated the bending stiffness gradient, in which the basal half is relatively stiff and the apical half is softer, whose good performance during copulation had been previously numerically demonstrated. The stiffness gradient is the result of the flagellum shape, which is cylindrical and tapered toward the tip. Moreover, the curved tip comprises a harder outer curve and a softer inner curve. Considering the findings of preceding studies, the flagellum works in the following way: (i) the bending stiffness gradient supports the flagellum, easily fitting to a shape of a highly coiled spermathecal duct, (ii) the stiffness property of the very tip may make the tip tougher, and (iii) the curled tip and homogeneously cylindrical shape of the organ help the very tip to fit the shape of the spermathecal duct of the female. Our study shows that the apparently simple flagellum penetration is achieved with numerous elaborate mechanical adaptations.
• Traumatic mating by hand saw-like spines on the internal sac in Pyrrhalta maculicollis (Coleoptera, Chrysomelidae, Galerucinae)

  Yoko Matsumura, Haruki Suenaga, Yoshitaka Kamimura, Stanislav N. Gorb

  ZOOKEYS (720) 77 - 89 1313-2989 2017/12 [Refereed][Not invited]
   

  Morphology of the aedeagus and vagina of Pyrrhalta maculicollis and its closely related species were investigated. The internal sac of P. maculicollis bears hand saw-like spines, which are arranged in a row. Healing wounds were found on the vagina of this species, whose females were collected in the field during a reproductive season. However, the number of the wounds is low in comparison to the number of the spines. In addition, males of P. tibialis bear one spinous sclerite on the internal sac, but the female of this species show no wounds on the vagina. The vaginal wall is thicker in P. maculicollis and P. tibialis in comparison to other studied species, whose males bear no spinous sclerite. This thickening in P. maculicollis is likely a counteradaptation to wound infliction. Pyrrhalta maculicollis has a narrow internal sac in comparison to that of other Pyrrhalta species. Narrow internal sacs with spines can be potentially disadvantageous because their movement during copulation likely enhances the risk of self-infliction. Males of Pyrrhalta species have tiny membranous projections densely covering the internal sac surface, and it is hypothesized that they prevent damaging their own internal sac during everting and withdrawing the internal sac with the spines.
• Eversion and withdrawal of an intromittent organ before sexual maturation prepares male beetles for copulation

  Yoko Matsumura, Takuya Kubo

  Royal Society Open Science 4 (8) 161029 - 161029 2017/08 [Refereed][Not invited]
   

  Some species of criocerine beetles have a hyper-elongated part of the intromittent organ called a flagellum. In resting position, the flagellum is stored in a specialized internal sac in the intromittent organ. This specialized state of the flagellum and internal sac is indispensable during copulation for flagellar insertion into the female spermathecal duct for sperm transfer. However, the morphogenesis of the flagellum does not generate the active state of the flagellum; rather, the flagellum is generated in an inactive and completely coiled state. After eclosion, males of Lema coronata evert and withdraw the internal sac multiple times before sexual maturation, without mounting a female. This behaviour serves to uncoil the flagellum and guide it into the active state with the aid of surface structures on the internal sac. A closely related species, Lema dilecta , also has a long flagellum and undergoes the same behaviour to place the flagellum in the active position. However, some other species of criocerine beetles with much shorter flagella can attain the active state without exhibiting this behaviour. Based on a previously proposed phylogenetic tree, we discuss the evolutionary history of the hyper-elongation of the flagellum and associated behaviour.
• Functional morphology and evolution of the hyper-elongated intromittent organ in Cassida leaf beetles (Coleoptera: Chrysomelidae: Cassidinae)

  Yoko Matsumura, Jan Michels, Esther Appel, Stanislav N. Gorb

  ZOOLOGY 120 1 - 14 0944-2006 2017/02 [Refereed][Not invited]
   

  The peculiar phenomenon of hyper-elongation of intromittent organs is well known in.a number of insect groups. However, the unresolved questions of how and why such a phenomenon originated independently many times continue to attract biologists' attention. To be able to detect the evolutionary driving mechanisms that enabled insects to repeatedly acquire such a peculiarity, first of all the structural key features and the mechanics of these organs have to be determined. In the present study, the morphology of the reproductive organs of two species of the beetle genus Cassida, with a special focus on the male structures, was scrutinised in detail during copulation and at rest using different microscopy techniques. We found that the hyper-elongated structure of the intromittent organ, called flagellum, is part of the male ejaculatory duct. When the flagellum is inserted into the female spermathecal duct, longitudinal muscles of the ejaculatory duct, but not the flagellum, are shortened. These results strongly suggest that the contraction of the longitudinal muscles of the ejaculatory duct causes propulsion of the flagellum into the highly spiralled spermathecal duct of the female. The tip of the cuticular flagellum is curled up, which can suggest that its physical properties differ from those of the rest of the flagellum. Considering the preceding modelling studies, this property aids the flagellum in penetrating within the highly spiralled and very variable female duct. Based on our morphological results and in comparison with the morphology of intromittent organs of other beetles, we discuss the evolutionary origin of the hyper-elongation in the Cassida species and propose a hypothesis that explains the independent origin of the hyper-elongation of intromittent organs. (C) 2016 Elsevier GmbH. All rights reserved.
• A New Record of Zoraptera (Insecta) from Kenya, with Remarks on their Habitat

  Yoko Matsumura, Laban Njoroge

  Journal of East African Natural History 105 (2) 213 - 222 1026-1613 2016/12 [Refereed][Not invited]
  
• Stiffness gradient of the beetle penis facilitates propulsion in the spiraled female spermathecal duct.

  Alexander E Filippov, Yoko Matsumura, Alexander E Kovalev, Stanislav N Gorb

  Scientific reports 6 27608 - 27608 2016/06/23 [Refereed][Not invited]
   

  It is well known that sexual selection is the main driving force of substantial diversity of genitalia found in animals. However, how it facilitates the diversity is still largely unknown, because genital morpho/physical features and motions/functional morphology of the structures in sexual intercourse are not linked for the vast majority of organisms. Here we showed the presence of material gradient and numerically studied an effect of stiffness gradient of the beetle penis during its propulsion through the female duct. We found that stiffness gradient on the penis essentially affects its propulsion. Microscopic investigation suggests the possibility that the tip of the hyper-elongated penis is softer than the rest of it, and our numerical model confirms that this type of distribution of stiffness gradient aids in faster propulsion than other types. This result indicates that previously ignored physical properties of genital materials are of crucial importance in evolutionary studies of genitalia.
• Male penile propulsion into spiraled spermathecal ducts of female chrysomelid beetles: A numerical simulation approach

  Alexander Filippov, Alexander Kovalev, Yoko Matsumura, Stanislav N. Gorb

  JOURNAL OF THEORETICAL BIOLOGY 384 140 - 146 0022-5193 2015/11 [Refereed][Not invited]
   

  Genital diversification in animals is an interesting evolutionary phenomenon. Sexual selection is the main driving force behind the diversification. However, evolutionary mechanisms that have established and maintained variations in genitalia shape parameters observed in related species are not well understood. Here, for the first time, we used numerical simulations to test the hypothesis that variations in female spermathecal duct shapes among related beetle species mechanically interfere with penile propulsion in varying ways. Our numerical simulations showed that high curvature of the spiraled spermathecal ducts of the female have effects with a threshold-based interaction on male penile insertion. The relative size of spirals observed in the beetle, Cassida rubiginosa, studied here is not small enough to interfere with penile propulsion. But the model revealed that propulsion is impeded by the presence of reverse turns in spermathecal ducts. This type of morphology leads to an increase in the velocity of the propulsion but also to an increase in the propulsion energy cost for males. Our results showed that quantitative differences in spermathecal duct shape can mediate qualitative differences in penile motion. This explains, in part, the mechanism behind origin and maintenance of genital divergence among closely related species in general. (C) 2015 Elsevier Ltd. All rights reserved.
• The intermediate sperm type and genitalia of Zorotypus shannoni Gurney: evidence supporting infraordinal lineages in Zoraptera (Insecta)

  Romano Dallai, Marco Gottardo, David Mercati, Jose Albertino Rafael, Ryuichiro Machida, Yuta Mashimo, Yoko Matsumura, Rolf Georg Beutel

  ZOOMORPHOLOGY 134 (1) 79 - 91 0720-213X 2015/03 [Refereed][Not invited]
   

  The sperm ultrastructure and the male and female genital apparatus of Zorotypus shannoni were examined and documented in detail, mainly using transmission electron microscopy micrographs. The findings suggest an evolutionary trend shared with Z. hubbardi and Z. impolitus. The three species are characterized by enlarged mitochondrial derivatives and related modifications. Giant sperm are probably a synapomorphy of Z. hubbardi and Z. impolitus, whereas an intermediate condition of this feature is found in Z. shannoni. The monophyletic origin of Z. caudelli, Z. magnicaudelli, Z. huxleyi and Z. weidneri is suggested by characteristically modified axonemes. The presence of extra-acrosomal material is also an unusual feature for Zoraptera, but this condition also occurs in the majority of polyneopteran groups. The long and convoluted female spermathecal duct with secretory and duct-forming cells is a constant feature in Zoraptera. The enlarged seminal receptacle suggests an evolutionary link between the male genital structures and the sperm size on one hand, and the size of the female spermatheca on the other. The small and otherwise uniform group Zoraptera exhibits a remarkable variation of sperm types and genital structures, suggesting the impact of different types of selection. It is likely that cryptic female choice plays a major role in shaping the genital apparatus.
• Cephalic anatomy of Zorotypus weidneri New, 1978: new evidence for a placement of Zoraptera.

  Matsumura, Y, Wipfler, B, Pohl, H, Dallai, R, Machida, R, Mashimo, Y, Câmara, JT, Rafael, JA, Beutel, R

  Arthropod Systematics & Phylogeny 73 (1) 85 - 105 2015 [Refereed][Not invited]
  
• Evolution of a giant intromittent organ in Scydmaeninae (Coleoptera: Staphylinidae): functional morphology of the male postabdomen in Mastigini.

  Paweł Jałoszyński, Yoko Matsumura, Rolf G Beutel

  Arthropod structure & development 44 (1) 77 - 98 2015/01 [Refereed][Not invited]
   

  We compared the postabdominal architecture of Mastigini with extremely long (Stenomastigus) or short (Palaeostigus) aedeagus. A novel mode of copulation was discovered: males of Stenomastigus insert a paramere between the female's abdomen and elytra, and the intromission is stabilized by several structures of both sexes. The intrinsic aedeagal mechanism is indicated as responsible for inflating the endophallus, and the long flagellum does not penetrate the ductus spermathecae during copulation. The structure of the flagellum suggests that it is primarily responsible for the sperm transfer. Asymmetrical postabdominal rotators of the aedeagus were only found in Stenomastigus; they presumably facilitate the withdrawal of the genitalia; their origin as bundles separated from larger muscles is postulated. We discuss a scenario in which the evolution of elongated genitalia was facilitated by the lack of structural constraints and existing preadaptations. Benefits of stabilizing the copulation and intromission are indicated as the driving force for the evolution of extremely long aedeagi, while the short aedeagi might have the advantage of freedom of movements facilitating the initiation of copulation by males. Disruptive selection is suggested as a working hypothesis to further investigate mechanisms that have played a role in the evolution of genital structures of Mastigini.
• 100 years Zoraptera—a phantom in insect evolution and the history of its investigation

  Y. Mashimo, Y. Matsumura, R. Machida, R. Dallai, M. Gottardo, K. Yoshizawa, F. Friedrich, B. Wipfler, R.G. Beutel

  Insect Systematics & Evolution 45 (4) 371 - 393 2014/10/04 [Refereed][Not invited]
   

  Zoraptera are a cryptic and enigmatic group of insects. The species diversity is lower than in almost all other groups of Hexapoda, but may be distinctly higher than presently known. Several new species were described from different regions recently. The systematic placement was discussed controversially since the group was discovered 100 years ago. Affinities with Isoptera and Psocoptera were discussed in earlier studies. A sister group relationship with Acercaria (Psocodea, Thysanoptera, Hemiptera) was proposed by W. Hennig, for the first time based on a strictly phylogenetic argumentation. More recent studies consistently suggest a placement among the “lower neopteran orders” (Polyneoptera). Close affinities to Dictyoptera were proposed and alternatively a sister group relationship with Embioptera or with Embioptera + Phasmatodea (Eukinolabia), respectively. The precise placement is still controversial and the intraordinal relationships are largely unclear. Recent transcriptome analyses tentatively suggest a clade Zoraptera + Dermaptera as sister group of all other polyneopteran orders. The oldest fossils are from Cretaceous amber. An extinct genus from this era may be the sister group of all the remaining zorapterans. The knowledge of the morphology, development and features related to the reproductive system greatly increased in recent years. The general body morphology is very uniform, whereas the genitalia differ strongly between species. This is likely due to different kinds of selection, i.e. sexual selection in the case of the genital organs. The mating pattern also differs profoundly within the order. A unique external sperm transfer occurs in Zorotypus impolitus. A species-level phylogeny and more investigations of the reproductive system should have high priority.
• Molecular phylogeny of the leaf beetle subfamily Criocerinae (Coleoptera: Chrysomelidae) and the correlated evolution of reproductive organs

  Yoko Matsumura, Izumi Yao, Rolf G. Beutel, Kazunori Yoshizawa

  ARTHROPOD SYSTEMATICS & PHYLOGENY 72 (2) 95 - 110 1863-7221 2014/07 [Refereed][Not invited]
   

  Phylogenetic relationships among major groups of Criocerinae were reconstructed using molecular data (mitochondrial cytochrome oxidase I and 12S rDNA, and nuclear histone 3). The monophyly of Criocerinae was consistently and robustly supported. The Lema group including Lema, Oulema and Neolema was recovered as a clade, with the latter two genera imbedded within Lema. The Lilioceris group was placed as the sister taxon of the Lema group, and the genus Crioceris was identified as the sister taxon of the Lilioceris + Lema groups. The monophyly and/or validity of Mecoprosopus Chujo, 1951 and the subgenera Lema, Petauristes Latreille, 1829, Quasilema Monros, 1960, Microlema Pic, 1932, and Bradyceris Chujo, 1951 were not confirmed. The monophyly of the subgenus Lema except for the type species L. cyanea was supported by molecular and morphological data, and we termed it the cyanella clade. The present molecular phylogeny was compared with previous concepts with respect to the validity of each genus/subgenus. A revision of several genera is necessary. Based on the phylogenic result, the character evolution of the reproductive organs was analyzed. The ancestral states of this character system were parsimoniously reconstructed. Various shapes of the spermatheca were observed in the subfamily. A convoluted spermatheca evolved once, and reversals to the ancestral state took place several times independently. An elongation of a part of the intromittent organ also occurred several times independently. The length of the male and female reproductive ducts, which are in physical contact during copulation, showed a tight positive correlation even after removing phylogenetic effects. This strongly suggests coevolution between the male and female genital length.
• Comparative morphology of spermatozoa and reproductive systems of zorapteran species from different world regions (Insecta, Zoraptera)

  Romano Dallai, Marco Gottardo, David Mercati, Ryuichiro Machida, Yuta Mashimo, Yoko Matsumura, Jose Albertino Rafael, Rolf Georg Beutel

  ARTHROPOD STRUCTURE & DEVELOPMENT 43 (4) 371 - 383 1467-8039 2014/07 [Refereed][Not invited]
   

  The male and female reproductive apparatus of Zorotypus magnicaudelli (Malaysia), Zorotypus huxleyi (Ecuador) and Zorotypus weidneri (Brazil) were examined and documented in detail. The genital apparatus and sperm of the three species show only minor differences. The testes are larger in Z magnicaudelli. Z huxleyi lacks the helical appendage in the accessory glands. A long cuticular flagellum is present in Z. magnicaudelli and in the previously studied Zorotypus caudelli like in several other species, whereas it is absent in Z weidneri, Z. huxleyi, Zorotypus hubbardi, Zprotypus impolitus and Zorotypus guineensis. Characteristic features of the very similar sperm are the presence of: a) two dense arches above the axoneme; b) a 9 + 9+2 axoneme with detached subtubules A and B of doublets 1 and 6; c) the axonemal end degenerating with enlarging accessory tubules; d) accessory tubules with 17 protofilaments; e) three accessory bodies beneath the axoneme; and f) two mitochondrial derivatives of equal shape. The first characteristic (a) is unknown outside of Zoraptera and possibly autapomorphic. The sperm structure differs distinctly in Z. impolitus and Z. hubbardi, which produce giant sperm and possess a huge spermatheca. The presence of the same sperm type in species either provided with a sclerotized coiled flagellum in males or lacking this structure indicates that a different organization of the genital apparatus does not necessarily affect the sperm structure. The flagellum and its pouch has probably evolved within Zoraptera, but it cannot be excluded that it is a groundplan feature and was reduced several times. The fossil evidence and our findings suggest that distinct modifications in the genital apparatus occurred before the fragmentation of the Gondwanan landmass in the middle Cretaceous. (C) 2014 Elsevier Ltd. All rights reserved.
• Two intromittent organs in Zorotypus caudelli (Insecta, Zoraptera): the paradoxical coexistence of an extremely long tube and a large spermatophore

  Yoko Matsumura, Kazunori Yoshizawa, Ryuichiro Machida, Yuta Mashimo, Romano Dallai, Marco Gottardo, Thomas Kleinteich, Jan Michels, Stanislav N. Gorb, Rolf G. Beutel

  BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY 112 (1) 40 - 54 0024-4066 2014/05 [Refereed][Not invited]
   

  Very unusual genitalia of the species Zorotypus caudelli are described. It contains the unique configuration of two different intromittent organs, one of them strongly elongated. Hyper elongated genitalia are known in different groups of insects. Males have to accommodate these unwieldy structures in the limited spaces of the abdomen and manipulate them acutely during copulation. A crucial question is how do species with elongated genitalia cope with these requirements? To investigate this, we studied key features enabling storage, insertion, and withdrawal of the elongated genitalia. The co-existence of an elongated narrow tube and a bulky spermatophore is a highly unusual and apparently paradoxical condition. However, we demonstrate that the tube is not involved in sperm transmission, whereas the large spermatophore is transferred to females by a membranous fold of the genitalia. The movement of the spermatophore is caused by haemolymph pressure, which likely also promotes the insertion of both intromittent organs. A comparison with the genital anatomy and reproductive mode in related groups suggests that the elongated tube and its accommodating pouch is a de novo structure, and that the ancestral sperm transport via spermatophore is a preadaptive condition for the acquisition of this unusual structure. (c) 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 112, 40-54.
• Giant spermatozoa and a huge spermatheca: A case of coevolution of male and female reproductive organs in the ground louse Zorotypus impolitus (Insecta, Zoraptera)

  Romano Dallai, Marco Gottardo, David Mercati, Ryuichiro Machida, Yuta Mashimo, Yoko Matsumura, Rolf G. Beutel

  ARTHROPOD STRUCTURE & DEVELOPMENT 43 (2) 135 - 151 1467-8039 2014/03 [Refereed][Not invited]
   

  The male and female genital apparatus of the recently discovered ground louse Zorotypus impolitus were examined using light and electron microscopy. The rounded testes and a large seminal vesicle are connected with a complex of four accessory glands by a long tapering ejaculatory duct. Two accessory glands have the same whitish coloration, whereas the third one is pale blue, and the elongated and cylindrical fourth one translucent. The sperm are the largest known in Hexapoda, 3 mm long and 3 mu m wide, with a volume of ca. 21,000 mu m(3); the ratio between the diameter of the axoneme and the width of the main body of the sperm ranges between 1:10 and 1:13. The exceptional width of the spermatozoa is due to an extreme enlargement of the mitochondrial derivatives and accessory bodies. A single sperm is contained in a small globular spermatophore (100 mu m). The highly unusual external transfer correlates with an atypical mating behavior. The male produces several to many spermatophores during the mating process. As in other zorapterans the ovaries are panoistic and the eggs bear two micropyles. An exceptionally large apical spermathecal receptacle is present; it is connected with the vagina by a long spermathecal duct, which varies structurally along its course. A correlation between the sperm size and the size of the spermatheca is likely. Ultrastructural features of different species support two strikingly different models of male and female reproductive apparatus in the small order Zoraptera. This is in stark contrast to the extreme uniformity of their external morphology. It is likely that sexual selection played a decisive role in the evolution of the reproductive system. (C) 2013 Published by Elsevier Ltd.
• Insect morphology in the age of phylogenomics: innovative techniques and its future role in systematics

  Frank Friedrich, Yoko Matsumura, Hans Pohl, Ming Bai, Thomas Hoernschemeyer, Rolf G. Beutel

  ENTOMOLOGICAL SCIENCE 17 (1) 1 - 24 1343-8786 2014/01 [Refereed][Invited]
   

  A brief account of the history of insect morphology is given. Different techniques and analytical methods used in current projects on insect morphology and phylogeny and their optimized combined application are described. These include fixation, dissection, maceration, histology (microtome sectioning), scanning electron microscopy (SEM), transmission electron microscopy (TEM), serial block-face scanning electron microscopy (SBFSEM), focused ion beam scanning electron microscopy (FIB/SEM), confocal laser scanning microscopy (CLSM), bleaching, micro-computed tomography (CT), computer-based three-dimensional reconstruction, focus stacking of digital images, geometric morphometrics and the storage of morphological metadata. The role of insect morphology in the age of phylogenomics is discussed.
• Parallel evolution of novelties: extremely long intromittent organs in the leaf beetle subfamily Criocerinae

  Yoko Matsumura, Ryuichiro Machida, Benjamin Wipfler, Rolf G. Beutel, Kazunori Yoshizawa

  EVOLUTION & DEVELOPMENT 15 (4) 305 - 315 1520-541X 2013/07 [Refereed][Not invited]
   

  Extreme elongation of a part of the intromittent organ, the flagellum, has occurred several times in Criocerinae (Chrysomelidae). These leaf beetles have acquired a specialized pocket to store the flagellum in the abdominal cavity, at the same time allowing a quick control of movements of this structure during copulation. We investigated the morphogenesis of the intromittent organs of species with and without a flagellum to discuss the evolutionary background of parallel evolution of novel structures. We found that the specialized pocket is formed by the invagination of an epidermal layer and a resultant rotation of the primary gonopore. Invagination itself is a well-known phenomenon in morphogenetic processes, which leads us to hypothesize that the novelty is formed by co-opting a previously acquired genetic system. A large open-space is present within the intromittent organ during the entire morphogenesis in species without a flagellum, and the invagination in the species with a flagellum grows in the corresponding area. This means that there are no physical impediments for the growth of a large pocket. In addition the sites of muscular attachments in the species with a flagellum are also different from those without it. The differentiation of muscles is completed immediately before adult emergence, which means the muscles are adjustable during the entire morphogenesis in this group. Simple modifications probably based on a co-option of previously acquired genetic systems, the potential space for adding a new element, and an adjustable factor in morphogenesis of the intromittent organ facilitate the parallel evolution of the extreme elongation.
• Divergent mating patterns and a unique mode of external sperm transfer in Zoraptera: an enigmatic group of pterygote insects

  R. Dallai, M. Gottardo, D. Mercati, R. Machida, Y. Mashimo, Y. Matsumura, R. G. Beutel

  Naturwissenschaften 100 (6) 581 - 594 0028-1042 2013/06 [Refereed]
  
• A New Synonym of Lema (Lema) dilecta BALY, 1873 (Coleoptera, Chrysomelidae)

  Matsumura, Y, Maruyama, M

  Elytra 3 (1) 173 - 174 2013 [Refereed][Not invited]
  
• On newly and recently recorded species of the genus Lema Fabricius (Coleoptera, Chrysomelidae, Criocerinae) from Taiwan.

  Chi-Feng Lee, Yoko Matsumura

  ZooKeys (262) 17 - 38 2013 [Refereed][Not invited]
   

  New records of four species (Lema lacertosa Lacordaire, 1845, Lema diversipes Pic, 1921, Lema cyanella (Linnaeus, 1758), Lema trivittata trivittata Say, 1824 and additional information on one recently recorded species (Lema solani Fabricius, 1798) are reported for Taiwan. Lema diversipes Pic, 1921 is removed from synonymy with Lema lacertosa Lacordaire, 1845; both species are redescribed. A lectotype is designated for Lema phungi Pic, 1924. The synonymies of Lema phungi Pic, 1924 and Lema jeanvoinei Pic, 1932 with Lema lacertosa Lacordaire, 1845 are supported. A revised key to the known species in Taiwan is provided.
• Homology of the internal sac components in the leaf beetle subfamily criocerinae and evolutionary novelties related to the extremely elongated flagellum

  Yoko Matsumura, Kazunori Yoshizawa

  JOURNAL OF MORPHOLOGY 273 (5) 507 - 518 0362-2525 2012/05 [Refereed][Not invited]
   

  Extremely elongated intromittent organs are found in a wide range of taxa, especially among insects. This phenomenon is generally thought to result from sexual selection, but it is predicted that limited storage space in the body cavity and the difficulty of using the elongated organs should have constrained the evolution of extreme elongation, neutralizing any selective advantage. Therefore, in groups with long intromittent organs, features that overcome these constraints may have evolved or coevolved together with intromittent organ elongation. Using a comparative morphological approach and outgroup comparisons, we identified potential constraints and key novelties that may neutralize such constraints in the leaf beetle subfamily Criocerinae. Observations of the internal sac structure throughout Criocerinae were performed. Comparing the results with preceding studies from outgroups, a ground plan of the criocerine internal sac was constructed. Our analysis also identified specific features that are always correlated with extreme elongation: the rotation of whole internal-sac sclerites and the possession of a pocket in which to store the elongated flagellum. The pocket is thought to be formed by the rotation of the sclerites, markedly altering internal sac shape from the criocerine ground plan. Onlythe clades that have acquired this derived state contain species with an elongated flagellum that distinctly exceeds the median lobe length. It is presumed that these character correlations evolved independently three times. The detected character correlations corroborate the hypothesis that there are latent adaptive constraints for the evolution of extremely elongated intromittent organs. The constraints may have been neutralized by the alteration from the criocerine ground plan resulting in the formation of a storage pocket. In conclusion, deviation from the criocerine ground plan isconsidered to be the evolutionary innovation that neutralized the latent adaptive constraints of flagellum elongation in the subfamily Criocerinae. J. Morphol., 2012. (c) 2011 Wiley Periodicals, Inc.
• Revision of the Lema (Lema) concinnipennis Baly, 1865 species group (Coleoptera: Chrysomelidae: Criocerinae) in Japan

  Y. Matsumura, S. Sasaki, S. Imasaka, M. Sano, M. Ôhara

  Journal of Natural History 45 (25-26) 1533 - 1561 0022-2933 2011/07 [Refereed][Not invited]
  
• ハムシの情報交換会 「クリ・クラ」 の誕生と, ササキクビボソハムシ (新称) の日本からの再発見の経緯および紹介.

  松村洋子, 佐々木茂美, 今坂正一

  さやばね ニューシリーズ 3 13 - 19 2011 [Refereed][Not invited]
  
• Isolation of nine polymorphic microsatellite loci from the leaf beetle, Lema (Lema) coronata (Coleoptera: Chrysomelidae: Criocerinae)

  Yoko Matsumura, Izumi Yao

  EUROPEAN JOURNAL OF ENTOMOLOGY 108 (4) 697 - 699 2011 [Refereed][Not invited]
   

  Sexual selection is thought to result in an elongation of genitalia in insects. Part of the genitalia of the leaf beetle Lema (Lema) coronata Baly is approximately twice the body length in both sexes. Nine microsatellite loci were isolated from L. (L.) coronata for use in future studies on the correlation between genital length and reproductive success. The nine loci were polymorphic, with three to six alleles per locus recorded in 40 individuals. Observed heterozygosity ranged from 0.08 to 0.38 and expected heterozygosity from 0.51 to 0.75. The non-exclusive probability of the second parent and the identity calculated from the set of loci were 0.011 and < 0.001, respectively. A deviation from the Hardy-Weinberg equilibrium was detected at all nine loci, i.e. significant heterozygote deficiencies, and several hypotheses accounting for this are discussed. The isolated loci carried independent information. Five polymorphic loci were amplified in a related sympatric species, L. (L.) scutellaris, which has relatively short genitalia. These microsatellite makers will be used to determine the paternity of offspring of females multiply mated in the laboratory and compare the selection pressures operating on genital length in these closely related species.
• Insertion and withdrawal of extremely elongated genitalia: a simple mechanism with a highly modified morphology in the leaf beetle, Lema coronata

  Yoko Matsumura, Kazunori Yoshizawa

  BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY 99 (3) 512 - 520 0024-4066 2010/03 [Refereed][Not invited]
   

  Complicated genital structures are widely known in many animals. It is assumed that an increasing morphological complexity of genital structures would also increase the difficulty of inserting and withdrawing the structures. We examined the insertion and withdrawal mechanisms of extremely elongated genitalia in the Japanese leaf beetle, Lema (Lema) coronata. Insertion and withdrawal processes are completed quickly. Investigation of genital morphology showed that there are no protractor or retractor muscles attached to the elongated part. Instead, the elongated part is tightly enveloped by a membrane. Because of the close fit between the elongated part and its surrounding membrane, eversion of the membrane allows for insertion of the elongated part, and retraction of the membrane induces withdrawal of the elongated part. This surrounding membrane makes it possible to store the median ejaculatory guide (MEG) in a small genital cavity, with the basal portion of the elongated part extending internally against the entrance. This unusual character state is observed only in members of the subgenus Lema, which also have the elongated part. This condition can be considered to be a preadaptation for extreme elongation of genitalia. (C) 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99, 512-520.
• Mating behavior and genital damage during copulation in the leaf beetleLema coronata(Chrysomelidae: Criocerinae)

  Yoko MATSUMURA, Shin-ichi AKIMOTO

  Entomological Science Blackwell Publishing 12 (2) 215 - 217 1343-8786 2009/06 [Refereed]
   

  The criocerine leaf beetle Lema coronata Baly has extremely long genitalia that reach more than twice the body length in both sexes. We observed mating behavior of this species in the laboratory and inspected the male genital morphology using a scanning electron microscope. The males did not perform pre-copulatory courtship and post-copulatory guarding of the mates, and copulation lasted only for about 30 min. The surface of male genitalia is smooth without any special structures at the tip. A fragment of broken male genitalia was detected in the spermathecal duct of one female. We discuss the adaptive significance of male genital damage and the selective factor of elongated genitalia.
• Comparative morphology of internal reproductive systems in leaf beetles of the Donaciinae and Criocerinae (Coleoptera: Chrysomelidae) and its implication for the phylogeny

  YOKO MATSUMURA, KUNIO SUZUKI

  Zootaxa 1845 (1) 1 - 1 1175-5326 2008/08/08 [Refereed][Not invited]
   

  We compared the morphology of the internal and external reproductive organs of both sexes among species of the leaf beetle subfamily Donaciinae and its sister taxon Criocerinae. Using nine characters of the reproductive system, we attempted to reconstruct the phylogenetic tree for the two subfamilies combined. For this study, we used 11 Japanese species (including 2 subspecies) of 2 genera in the Donaciinae and 16 Japanese species of 4 genera in the Criocerinae. Morphological comparison revealed that the internal reproductive system exhibits a large diversity even in each subfamily. In particular, the morphology of the spermathecal organ varies greatly among genera or subgenera. In the subgenus Lema, we found a marked apomorphic state, that is, an extremely extended spermathecal duct in females and a similarly extended filiform structure on the internal sac in males. Phylogenetic analysis yielded two most parsimonious trees, which differ in criocerine relationship. In seven of the nine characters, the evolution of an apomorphic state was consistent with previous phylogenetic hypotheses.

MISC

• ハムシの精子貯蔵器官，受精嚢．

  松村洋子  昆虫と自然  57-  (1)  10  -13  2022  [Not refereed][Not invited]
  
• 体より長い交尾器を進化させた昆虫たち．

  上村佳孝, 松村洋子  昆虫と自然  52-  (1)  8  -11  2017  [Not refereed][Not invited]
  
• コルリクビボソハムシ（ハムシ科，クビボソハムシ亜科）中部・近畿中国地方の2府3県にも産す．

  鈴木邦雄, 安江梓, 松村洋子  甲虫ニュース  153-  9  -10  2006  [Not refereed][Not invited]
  
• 春季残雪上で活動するハムシ3種の観察．

  鈴木邦雄, 松村洋子  甲虫ニュース  154-  22  -23  2006  [Not refereed][Not invited]
  

Research Projects

• 交尾器の多様性の出現とその維持機構を昆虫交尾器バイオメカニクスで解き明かせるか

  日本学術振興会：科学研究費助成事業

  Date (from‐to) : 2023/04 -2028/03 

  Author : 松村 洋子
• 折り紙をする虫オトシブミ科にみられる多様な揺籃形成行動の進化史解明

  秋山記念生命科学振興財団：研究助成（奨励）

  Date (from‐to) : 2023/06 -2024/03 

  Author : 松村洋子
• 昆虫の交尾器多様化メカニズム: 交尾器と繁殖生態は共多様化してきたのか？

  北海道大学：北海道大学マイクロン女性研究者ロールモデル育成研究助成

  Date (from‐to) : 2022/08 -2023/03 

  Author : 松村洋子
• How have animal genitalia co-diversified between the sexes? Linking biomechanics to genital evolution in insects

  German Research Foundation (DFG)：

  Date (from‐to) : 2021/06 -2022/04 

  Author : 松村洋子
• Functional morphology and biomechanics of sexual intertwining in beetles and their evolutionary implications

  German Research Foundation (DFG)：

  Date (from‐to) : 2017/06 -2020/08 

  Author : 松村洋子
• バイオメカニクスから紐解く雌雄交尾器の共多様化機構

  日本学術振興会：科学研究費助成事業 特別研究員奨励費

  Date (from‐to) : 2015/04 -2016/12 

  Author : 松村 洋子

   

  雌雄交尾器の共多様化が如何にして生じたかに答えるため，①雌雄交尾器の物理的相互作用がどう達成されるのか，②雌雄交尾器の形の違いがその相互作用に影響をもたらすか，という疑問にバイオメカニカルな立場から取り組んだ．①雌雄交尾器の種間変異の記載と定量化，②物理的相互作用の断片的視覚化と物性の理解から雌雄交尾器の機能や動きがもたらされるメカニズムを機械的に説明，③実験的に２の仮説の検証のステップで進めた．雌雄交尾器が物理的に相互作用する過程のうち，本年度は昆虫の極端に長い交尾器を介した射精プロセスを対象に，実体・光学・電子・レーザー顕微鏡，X線μCTを駆使し，以下のことを明らかにした． １．極端に長い交尾器のサイズ（直径）が，交尾器の長さ・体サイズ・系統関係と関係なく種間で雌雄共に著しく変異する（雄交尾器：2μmから数10μm）． ２．上の計測値を基に①精液がオス交尾器の管を表面張力で満たすのに要する時間，②精液をオス交尾器の管から押し出すのに必要な力を計算した．その結果，どの種でも表面張力だけで2cm程度の長さのオス交尾器の管を容易に濡らせること，一方で精液の雌への受け渡しプロセスはオス交尾器の直径によってメカニズムが異なることが，理論的に示された．直径が2μmの種では，精液を押し出すには昆虫では不可能なほど大きな力が必要であるが，直径が数10μmの種では，精液はオス側の押し出す力でメスへ受け渡し可能である． ３．オス交尾器の直径が比較的大きな種ではオスの交尾器に発達した筋肉が認められポンプとして機能することが示唆されるのに対し，直径の小さな種では類似の構造は認められなかった．後者については，オス側とメス側を満たす液体の濃度勾配などから能動的に精液がオスからメスへ流れる可能性が考えられる．次年度，実験的にその可能性を確かめるため，実験を検討中である．
• 雌雄の長い交尾器の共進化をもたらす性的対立のメカニズム

  公益財団法人 山田科学振興財団：海外長期派遣

  Date (from‐to) : 2014/06 -2015/03 

  Author : 松村洋子
• 適応的制約は新規形質の進化に影響をもたらしてきたか-昆虫綱の極端に長いペニスの例

  日本学術振興会：科学研究費助成事業 特別研究員奨励費

  Date (from‐to) : 2012/06 -2014/05 

  Author : 松村 洋子
• 雌雄交尾器の急速な多様化と共進化メカニズムの解明

  日本学術振興会：科学研究費助成事業 特別研究員奨励費

  Date (from‐to) : 2010/04 -2012/03 

  Author : 松村 洋子

   

  【クビナガハムシ亜科の系統推定とオス・メス交尾器の詳細な形態観察から,交尾器の伸長現象と連動したオス・メスの複雑な共進化の全貌が解明されつつある】 一般に繁殖に関わる形質は,他の形態形質では区別ができない種間でも,顕著な差異を示す例が多く知られる.交尾器特有の多様性を生む原動力は性淘汰・性的対立によると考えられ,行動生態学的な視点からの研究が行われてきた.一方で,その多様な形態をもつ交尾器の進化史はこれまであまり着目されてこなかった.さらにオス・メス交尾器の共進化の研究もサイズという一面しか捉えられてこなかった.形態形質の変化は個体発生の変更によってもたらされ,発生単位の構成要素間で連動した形態変化が起こることが十分に予想される.しかし,これまでにそういった発想で繁殖形質の網羅的な形態観察に基づく共進化史を推定した例はない.本研究では,これまで見落とされてきたサイズ以外の要素も含めたオス・メス交尾器の共進化の実態解明を目的とし,クビナガハムシ亜科に見られる交尾器の伸長現象を取上げた.これまで良く知られているように,オス・メス間の交尾器長の共変化に加え,メス側の構造に,オスの伸長部の有無と連動した以下の変化傾向があることが分かった:(1)交尾時にメス側の受入れ口となる部位に観察されるパッドの有無,(2)メス膣の表面に観察される剛毛のパッチの位置,(3)メスの精子貯蔵器官の複雑さ.さらに,オスの伸長部の長さがある閾値を越える否かで,オスの伸長部を取り巻く膜の表面構造が劇的に変化することが分かった.現在,形態観察に加えて本分類群の分子系統樹の構築を進めている.今後は,これを基に,交尾器の形質状態の祖先・子孫関係を決定し,オス・メス交尾器の共進化史を提示する.