{"title":"Host body size as a factor determining the egg complement of Strepsiptera, an insect parasite","authors":"Yasuo Maeta , Kimitaka Takahashi , Norihide Shimada","doi":"10.1016/S0020-7322(97)00033-0","DOIUrl":"10.1016/S0020-7322(97)00033-0","url":null,"abstract":"<div><p>The egg complement (total number of eggs produced by a single female) differs greatly among the species of Strepsiptera. The maximum is found in <em>Stichotrema dallatorreanum</em> (750,000 eggs), and the minimum in <em>Triozocera minor</em> (984 eggs). Based on the egg complement of 31 species in 11 genera, the following conclusions were drawn: (1) The egg complement is generally smaller in those species whose hosts gregariously cohabit in a very limited area, or are distinct flower-visitors, compared with those whose hosts display the above two traits weakly; (2) The egg complement is determined by the size of the maternal body. The size of female strepsipterans is reduced when they parasitize smaller host such as males and workers, as compared with those that parasitize larger host such as females and queens; likewise, the size of the strepsipterans becomes larger on increase in size of hosts, showing that their egg complements are principally determined by the size of host species; (3) The increase in the egg complement is compensated for by the reduction in egg size. The relative egg size (length of the firstinstar larva/length of maternal body) is conspicuously reduced according to an increase in the size of the female strepsipterans.</p></div>","PeriodicalId":100701,"journal":{"name":"International Journal of Insect Morphology and Embryology","volume":"27 1","pages":"Pages 27-37"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0020-7322(97)00033-0","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74103182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Testis morphology and spermatogenesis in two species of Elenchus (Strepsiptera : Elenchidae)","authors":"Marcella Carcupino , Jeyaraney Kathirithamby , Massimo Mazzini","doi":"10.1016/S0020-7322(97)00029-9","DOIUrl":"10.1016/S0020-7322(97)00029-9","url":null,"abstract":"<div><p>Testes ultrastructure and spermatogenesis were studied in two species of Strepsiptera (Insecta), namely, <em>Elenchus tenuicornis</em> and <em>E. japonicus</em>, using light and electron microscopy. In both species, the testis is paired and consists of several large irregularly shaped follicles. Each follicle consists of a single clone of germ cells surrounded by a thin epithelium. During the larval and pupal stages, all the germ cells of each testis develop synchronously, and at eclosion, the gonads contain solely mature sperm. One of the most interesting findings is the morphogenesis of a large nuclear vesicle bounded by the fenestrate part of the nuclear envelope. This vesicle contains an electron-dense spherical structure, the chromatoid body. At the end of spermiogenesis, both the nuclear vesicle and its chromatoid body are eliminated with the excess cytoplasm. Large drops of residual cytoplasm containing several nuclear vesicles are present in the lumen of the testis and inside the cytoplasm of phagocytic cells.</p></div>","PeriodicalId":100701,"journal":{"name":"International Journal of Insect Morphology and Embryology","volume":"27 1","pages":"Pages 9-19"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0020-7322(97)00029-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84557940","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Developmental stages of Caenocholax fenyesi Pierce (Strepsiptera : Myrmecolacidae): Descriptions and significance to the higher taxonomy of Strepsiptera","authors":"Jerry L. Cook, S.Bradleigh Vinson, Roger E. Gold","doi":"10.1016/S0020-7322(97)00030-5","DOIUrl":"10.1016/S0020-7322(97)00030-5","url":null,"abstract":"<div><p>The first instar, secondary larva, and tertiary larva of <em>Caenocholax fenyesi</em> Pierce (Strepsiptera; Myrmecolacidae) are described. This is the first description of these stages from the genus <em>Caenocholax</em> and the sixth of a first instar, free-living larva, and second of secondary and tertiary larvae in the family Myrmecolacidae. Morphological characters of <em>C. fenyesi</em> are discussed, as are characters that might have taxonomic significance in the phylogeny of the Strepsiptera. The results of our study suggest that the characters of the first instar that are the best candidates for structures with taxonomic importance are: number and location of ocelli, location of spines, and leg structures of the first-instar.</p></div>","PeriodicalId":100701,"journal":{"name":"International Journal of Insect Morphology and Embryology","volume":"27 1","pages":"Pages 21-26"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0020-7322(97)00030-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82795782","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Host-parasitoid associations of Strepsiptera: Anatomical and developmental consequences","authors":"Jeyaraney Kathirithamby","doi":"10.1016/S0020-7322(97)00031-7","DOIUrl":"10.1016/S0020-7322(97)00031-7","url":null,"abstract":"<div><p>The strepsipteran host-parasitoid system is complex and unique, due to total dependence of the parasitoid on a <em>living</em> host for its survival. As a result of this, the eggs of stylopised <em>Segestidea novaeguineae</em> (Brancsik) (Orthoptera : Tettigoniidae) are severely deformed and have a bulbous protrusion. The structure of the chorion of the eggs in stylopised and unstylopised hosts was studied and is described. The moulting sequence in the endoparasitic, female <em>Stichotrema dallatorreanum</em> Hofeneder, the outer layers of the germ cells in the female strepsipteran, and the ultrastructure of the rickettsia-like microorganisms, found mainly in the female Strepsiptera, are discussed.</p></div>","PeriodicalId":100701,"journal":{"name":"International Journal of Insect Morphology and Embryology","volume":"27 1","pages":"Pages 39-51"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0020-7322(97)00031-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79560192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Reductions and new inventions dominate oogenesis of Strepsiptera (Insecta)","authors":"Jürgen Büning","doi":"10.1016/S0020-7322(97)00028-7","DOIUrl":"10.1016/S0020-7322(97)00028-7","url":null,"abstract":"<div><p>The endoparasitic life of strepsipterans (Insecta), especially neotenic females, reduces to a great extent external and internal organs. Light and electron microscopic investigation of ovaries of <em>Elenchus tenuicornis</em> (Kirby) confirms the following: (1) somatic tissues of ovaries are totally reduced, with the exception of some cells surrounding germ cell clusters; (2) a previtellogenic growth phase of oocytes is reduced; (3) nurse cells remain diploid and their membranes degenerate at the onset of vitellogenesis; (4) vitellogenesis is reduced, vitellin and fat vacuoles contribute only 50% to the final egg volume; and (5) chorionogenesis is reduced to a vitellin membrane. However, some features of normal development remain, allowing classification of the ovary type as polytrophic meroistic: (1) germ cells undergo synchronized, incomplete divisions, following the 2<sup>n</sup> rule, where all former intercellular bridges become localized in one cystocyte, while the other has none; and (2) only one cell is determined as the oocyte, all other cystocytes serve as nurse cells and the surrounding somatic cells transform into follicular cells. Novel events in oogenesis of strepsipterans include fission of clusters during the phase of cluster mitoses, and protection of oocyte nuclei, while nurse cell nuclei degenerate in the same cytoplasm.</p></div>","PeriodicalId":100701,"journal":{"name":"International Journal of Insect Morphology and Embryology","volume":"27 1","pages":"Pages 3-8"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0020-7322(97)00028-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73515895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Phylogenetic position of the Strepsiptera: Review of molecular and morphological evidence","authors":"Michael F. Whiting","doi":"10.1016/S0020-7322(97)00032-9","DOIUrl":"10.1016/S0020-7322(97)00032-9","url":null,"abstract":"<div><p>Molecular evidence of the monophyly of the Halteria (Strepsiptera + Diptera) is reviewed. The majority of morphological characters, which have classically been used to establish a Strepsiptera + Coleoptera sister group, are rejected, because they are based on erroneous interpretations of strepsipteran morphology. The scorings of 31 morphological characters, which directly relate to the phylogenetic position of Strepsiptera, are provided, and their distribution and optimization on the molecular + morphological tree is discussed. Of these, 13 characters specifically support the placement of Strepsiptera within the Mecopterida; seven of which are based on the optimization of inapplicable or missing data, and six of which are based on states that can be scored for Strepsiptera. Only a single character (posteromotorism) suggests a sister group relationship with the Coleoptera. The morphological and molecular data are largely congruent, and suggest that the Strepsiptera are sister group to the Diptera.</p></div>","PeriodicalId":100701,"journal":{"name":"International Journal of Insect Morphology and Embryology","volume":"27 1","pages":"Pages 53-60"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0020-7322(97)00032-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73131857","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Olfactory sensilla in crustaceans: Morphology, sexual dimorphism, and distribution patterns","authors":"Eric Hallberg, Kjell U.I. Johansson, Rita Wallén","doi":"10.1016/S0020-7322(97)00019-6","DOIUrl":"10.1016/S0020-7322(97)00019-6","url":null,"abstract":"<div><p>The morphological variation of crustacean olfactory sensilla is considerable, and appears to comprise both aesthetascs and male-specific sensilla. Male-specific sensilla have hitherto been described in some non-decapod groups, whereas the sexual dimorphism of the olfactory system of decapods is usually less prominent morphologically. The decapods usually have a larger number of sensory cells per aesthetasc sensillum than non-decapods. The aesthetascs and male-specific sensilla are arranged in arrays of varying density. Differences in the arrangement of sensilla probably reflect diverse stimulus acquisition behaviour.</p></div>","PeriodicalId":100701,"journal":{"name":"International Journal of Insect Morphology and Embryology","volume":"26 3","pages":"Pages 173-180"},"PeriodicalIF":0.0,"publicationDate":"1997-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0020-7322(97)00019-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85169570","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Pore structures in insect olfactory sensilla: A review of data and concepts","authors":"Rudolf Alexander Steinbrecht","doi":"10.1016/S0020-7322(97)00024-X","DOIUrl":"10.1016/S0020-7322(97)00024-X","url":null,"abstract":"<div><p>An historical overview is given of the most important discoveries and hypotheses regarding stimulus transport in insect olfaction. The great structural similarity between the pore tubules of olfactory single-walled wall-pore sensilla and the epicuticular filaments of non-olfactory cuticle may reflect not only a similar composition but also a similar transport mechanism. The new “wick concept” of pore tubules comprises 2 developmental periods. First, during ontogeny of the sensillum, pore tubules may be involved in the secretion of the material of the outermost epicuticular layers. The pore tubules may function like the wick in an oil lamp, taking up lipoid molecules from the sensillum lymph for outward transport. During the second period, after the sensillum has been completed, the pore-tubule wick may work as a dispenser of odorant molecules in an inward direction. The large surface of pore tubules as compared with the cross section of the outer pores could facilitate the binding of odorant molecules by the odorant-binding proteins in the sensillum lymph. In double-walled wall-pore sensilla, on the other hand, pore tubules are not involved in stimulus transport. In this class of olfactory sensilla, the dendrites are protected by a palisade of cuticular fingers, and openings between these fingers, the spoke channels, are the stimulus transport pathways. The fundamentally different topology of sensillar wall pores hints at a separate phylogenetic origin of the two categories of insect olfactory sensilla.</p></div>","PeriodicalId":100701,"journal":{"name":"International Journal of Insect Morphology and Embryology","volume":"26 3","pages":"Pages 229-245"},"PeriodicalIF":0.0,"publicationDate":"1997-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0020-7322(97)00024-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85880321","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Comparison of crustacean and insect mechanoreceptive setae","authors":"Yves Crouau","doi":"10.1016/S0020-7322(97)00020-2","DOIUrl":"10.1016/S0020-7322(97)00020-2","url":null,"abstract":"<div><p>Mechanosensitive cells of crustacean setae show important cytological differences compared with those of insects. The mechanosensitive cells in arthropod setae can be classified in 2 groups, which are structurally and functionally different. The typical mechanosensitive cells of insect setae show a tubular body at the tip of their dendrites, whereas mechanosensitive cells of aquatic crustaceans never show such a structure and are characterized by a 9 + 0 cilium, a large ciliary root and a scolopale cell. Among crustaceans, mechanosensory cells with a tubular body are observed only in terrestrial isopods. Therefore, it seems that the type of mechanosensitive cell associated with an arthropod seta is linked more to the physical environment than to the systematic group. It is also linked to differences in the kind of mechanosensitivity of the 2 types of cells: dendrites with a tubular body are compression-sensitive, whereas dendrites with a 9 + 0 type cilium would be stretch-sensitive. The presence of one type of cell in the terrestrial organisms and of the other in the aquatic animals may be explained by the physical characteristics of the environment.</p></div>","PeriodicalId":100701,"journal":{"name":"International Journal of Insect Morphology and Embryology","volume":"26 3","pages":"Pages 181-190"},"PeriodicalIF":0.0,"publicationDate":"1997-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0020-7322(97)00020-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86229956","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}