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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The Control of the Locust Spermatheca

Da Silva, Rosa 23 February 2011 (has links)
The coordination of reproductive events in female locusts involves the interaction between sensory cells, reflex loops, and central pattern generators. Neurochemicals have also been identified as being important for initiating and/or modulating the activities of reproductive tissues. The present thesis investigates the association of neurochemicals with the spermatheca and the neural control of the spermatheca via a central pattern generator (CPG) that is coordinated with other reproductive events. Crustacean cardioactive peptide (CCAP)-like immunoreactivity is present in the innervation to the spermatheca of adult locusts. CCAP enhances basal tonus, spontaneous and neurally-evoked contractions and may function as a neuromodulator/neurotransmitter at the locust spermatheca. No locustatachykinin (LomTK)-like immunoreactivity is present in the innervation to the spermatheca, or on the spermatheca itself, whereas allatostatin-like immunoreactivity is present. LomTK1 is a stimulator of spermathecal contractions, but allatostatin 1 does not lead to any changes in spermathecal contractions. It is likely that LomTK acts as a neurohormone on the spermatheca, while the role of allatostatin remains unknown. Tyramine-like immunoreactivity is present in the nerves that project to the spermatheca and throughout all of its regions. Quantification of tyramine revealed that there is more tyramine than octopamine present in the spermatheca, and that tyramine can be released from the spermatheca by electrical stimulation of the ventral ovipositor nerve (VON). Physiological assays reveal that both tyramine and octopamine increase spermathecal contractions. Tyramine may be a co-transmitter with octopamine at the locust spermatheca. There is likely a central pattern generator (CPG) that controls the spermathecal muscle activity, that is regulated by descending inhibition. Extracellular nerve and electromyographic recordings demonstrate that this CPG appears to be localized within the VIIth and VIIIth abdominal ganglia and is found to integrate with the CPG that regulates oviposition digging in locusts.
2

The Control of the Locust Spermatheca

Da Silva, Rosa 23 February 2011 (has links)
The coordination of reproductive events in female locusts involves the interaction between sensory cells, reflex loops, and central pattern generators. Neurochemicals have also been identified as being important for initiating and/or modulating the activities of reproductive tissues. The present thesis investigates the association of neurochemicals with the spermatheca and the neural control of the spermatheca via a central pattern generator (CPG) that is coordinated with other reproductive events. Crustacean cardioactive peptide (CCAP)-like immunoreactivity is present in the innervation to the spermatheca of adult locusts. CCAP enhances basal tonus, spontaneous and neurally-evoked contractions and may function as a neuromodulator/neurotransmitter at the locust spermatheca. No locustatachykinin (LomTK)-like immunoreactivity is present in the innervation to the spermatheca, or on the spermatheca itself, whereas allatostatin-like immunoreactivity is present. LomTK1 is a stimulator of spermathecal contractions, but allatostatin 1 does not lead to any changes in spermathecal contractions. It is likely that LomTK acts as a neurohormone on the spermatheca, while the role of allatostatin remains unknown. Tyramine-like immunoreactivity is present in the nerves that project to the spermatheca and throughout all of its regions. Quantification of tyramine revealed that there is more tyramine than octopamine present in the spermatheca, and that tyramine can be released from the spermatheca by electrical stimulation of the ventral ovipositor nerve (VON). Physiological assays reveal that both tyramine and octopamine increase spermathecal contractions. Tyramine may be a co-transmitter with octopamine at the locust spermatheca. There is likely a central pattern generator (CPG) that controls the spermathecal muscle activity, that is regulated by descending inhibition. Extracellular nerve and electromyographic recordings demonstrate that this CPG appears to be localized within the VIIth and VIIIth abdominal ganglia and is found to integrate with the CPG that regulates oviposition digging in locusts.
3

Internal Reproductive Organs of the Female Humpbacked Fly, Megaselia Scalaris Loew (Diptera : Phoridae)

Benner, D. B., Curtis, S. K. 01 January 1988 (has links)
The female reproductive system of the humpbacked fly Megaselia scalaris Loew (Diptera : Phoridae) was examined in whole mount preparations and serial sections. The system includes 2 ovaries, paired lateral oviducts, a common oviduct, and a genital chamber, opening externally through a gonopore, anteriad and ventrad to the anus. The ducts of the 2 accessory glands open independently into the dorsal region of the genital chamber. The terminal duct of a 2-armed spermatheca joins the right posterior and ventral wall of the genital chamber, immediately inside the gonopore. Passing dorally, the spermathecal duct lies immediately ventral to the duct of the right accessory gland. A short distance posteriad, it divides into two branches, each supplying an arm of the spermatheca. The genital chamber extends both anteriorly and posteriorly from its junction with the common oviduct, creating anterior and posterior compartments. In the right lateral wall of the genital chamber, a distinctive loop-shaped thickening (plate) resembles a darkened thread when it is observed through the integument. Features likely to have taxonomic utility include the posterior and ventral location of the terminal portion of the spermathecal duct; and the asymmetrically arranged, loop-shaped plate.
4

Análise cladística da tribo Dufouriini (Diptera, Tachinidae) / Cladistic analysis of the tribe Dufouriini (Diptera, Tachinidae)

Santis, Marcelo Domingos de 19 September 2016 (has links)
Tachinidae é uma das maiores famílias de Diptera, com cerca de 8500 espécies válidas. Atualmente, a família está dividida em quatro subfamílias: Phasiinae, Exoristinae, Tachininae e Dexiinae. Esta última contendo Dufouriini, tribo que possui 51 espécies em 13 gêneros, com distribuição mundial, e parasitóides de Coleoptera, principalmente Chrysomelidae e Curculionidae. Tem o seu posicionamento dentro de Dexiinae controverso, incluindo uma proposta de status de subfamília, e até família. Isso pode ser explicado pela necessidade de estudos filogenéticos para o grupo. Este trabalho tem como objetivo testar a monofilia de Dufouriini e de seus gêneros, além de reconstruir uma hipótese de relacionamento filogenético entre os gêneros da tribo, a partir de material disponível em coleções no país e no exterior. Como resultado do estudo morfológico detalhado que incluiu 34 espécies e 22 gêneros do grupo interno, foram construídos 185 caracteres para a análise filogenética, incluindo caracteres morfológicos do ovo, larva, pupário, adultos, incluindo terminália feminina e masculina e espermateca. A análise com pesagem igual dos caracteres resultou em uma única árvore mais parcimoniosa (L= 391; CI=63; RI=83), com Dufouriini sensu lato sendo recuperado como parafilético. Com base na filogenia obtida, os seus gêneros foram alocados da seguinte forma: 1) Cenosoma Wulp, 1890; Euoestrophasia Townsend, 1892; Jamacaria Curran, 1928 e Oestrophasia Brauer & Bergenstamm, 1889 transferidos para Oestrophasiini, tribo revalidada; 2) Mesnilana Emden, 1945 e Rhinophoroides Barraclough, 2005 incertae sedis em Dexiinae; e 3) Microsoma Macquart 1855 e Pandelleia Villeneuve, 1907 transferidos para Freraeini (além de Eugymnopeza Townsend e Freraea Robineau-Desvoidy que já faziam parte da tribo). Assim, Dufouriini sensu stricto, Oestrophasiini e Freraeini foram recuperadas como monofiléticas. Dufouriini, Freraeini e Oestrophasiini formam um clado que foi considerado como a subfamília Dufouriinae revalidado. A seguinte sinonímia é proposta: Comyopsis Townsend sin. nov. de Ebenia Macquart. As espermatecas foram caracterizadas morfologicamente, e, a sua relevância sistemática foi considerada de grande importância para recuperar grupos monofilético / Tachinidae is one of the largest families of Diptera, with about 8500 valid species. Currently, the family is divided into subfamilies: Phasiinae, Exoristinae, Tachininae and Dexiinae, the latter containing the tribe Dufouriini. This tribe has 51 species in 13 genera that are distributed worldwide, and are parasites of Coleoptera, especially Chrysomelidae and Curculionidae. It has a controversial positioning within Dexiinae, including a proposal of subfamily status, and even family. This can be explained by the necessity of a phylogenetic study for the group. The aim of this work was to test the monophyly of Dufouriini alongside its included genus, and to reconstruct phylogenetic relationships among the genera of the tribe, from material available in collections in the country and abroad. As a result of a detailed morphological study that included 34 species and 22 genera of the inner group, 185 characters were built for phylogenetic analysis including morphological characters from the egg, larva, puparium, adults, including female and male terminalia and spermatheca. The equal weighing analysis resulted in a single most parsimonious tree (L = 391; CI = 63, RI = 83), with Dufouriini sensu lato being recovered as paraphyletic. Based on the obtained phylogeny, the genera were allocated as follows: 1) Cenosoma Wulp, 1890; Euoestrophasia Townsend, 1892; Jamacaria Curran, 1928 and Oestrophasia Brauer & Bergenstamm, 1889 transferred for Oestrophasiini, tribe revalidated; 2) Mesnilana Emden, 1945 and Rhinophoroides Barraclough, 2005 incertae sedis in Dexiinae; and 3) Microsoma Macquart 1855 and Pandelleia Villeneuve, 1907 transferred for Freraeini (in addition to Eugymnopeza Townsend and Freraea Robineau-Desvoidy that belonged to the tribe). Therefore, Dufouriini sensu stricto, were recovered as monophyletic. Oestrophasiini and Freraeini were recovered as monophyletic. Dufouriini, Freraeini and Oestrophasiini form a clade that was considered as the subfamily Dufouriinae revalidated. The following new synonymy is proposed: Comyopsis Townsend syn. nov. of Ebenia Macquart. The spermatheca has been characterized morphologically, and their systematic significance was considered very important to recover monophyletic groups
5

Protection et survie du sperme chez les fourmis

Davila Garces, Juan Francisco 31 August 2018 (has links) (PDF)
Social Hymenoptera (wasps, ants, bees) possess a unique mode of reproduction. Typically, males produce the total amount of their spermatozoa during the nymphal phase solely from the energy reserves acquired during the larval phase. When the adult male hatches, the testes regress and the spermatozoa are then stored in their seminal vesicles. Mating takes place during a mating flight in which hundreds of males and females from surrounding colonies participate only once in their life. Sperm cells are transmitted during mating and are stored in the queen's spermatheca for the rest of its life (which can last several decades depending on the species). After mating, the male dies and the queen founds a new colony from the sperm received during the nuptial flight. She will never re-mate again and will use parsimoniously the spermatozoa to fertilize her eggs. Several factors are likely to dammage sperm cells, among them nutritional deficiencies during development, pathogens transmitted during mating or the immune defenses of the female that hosts sperm. Yet these sperm cells are extremly valuable because they are not renewable, and the queen will use them throughout her whole life to maintain a sufficient working force ensuring all the functions of the colony. The reproductive success of both males and females is highly dependent on the protection and maintain of spermatozoa.In this work we studied different factors that can affect the quantity, quality and protection of sperm in ants. The focus was made at three different stages: during the production of sperm cells, during their transmission at the time of mating and during their storage in the queen’s spermatheca. First, we showed that the investment in somatic development and in sperm quality take precedence over the production of large quantities of sperm cells. Second, we tested the presence and activity of two major components of the immune system (phenoloxidase system and antibacterial substances) in the sexual organs of virgin and mated ants, and we show that sperm protection uses specific systems which response is variable over time. In addition, we studed the temporal variations of these immune responses in the general insect system before and after mating. Finally, we examine the bacterial abundances and communities present in the reproductive organs at these same periods. We show the presence of some bacterial groups from the sperm storage organs that could play a role in the maintenance of spermatozoa. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished
6

Morfologia do sistema reprodutor masculino e aspectos do comportamento reprodutivo de Trypoxylon (Trypargilum) (Hymenoptera: Crabronidae) / Morphology of male reproductive system and aspects of the reproductive behavior of Trypoxylon (Trypargilum) (Hymenoptera: Crabronidae)

Moreira, Polyana Amaral 31 July 2007 (has links)
Made available in DSpace on 2015-03-26T13:30:56Z (GMT). No. of bitstreams: 1 texto completo.pdf: 558468 bytes, checksum: 2f11cae3c481f1cad0f71cb968b3f28e (MD5) Previous issue date: 2007-07-31 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Male reproductive tract of Trypoxylon (Trypargilum) has the basic pattern of Hymenoptera, with morphological variations that characterize the subgenus. It is formed by a pair of testicles, two deferent ducts and one ejaculatory duct. In each deferent duct there is an enlarged region, the seminal vesicle, with an accessory gland opening in the end of it. Each testicle has three follicles which have germ cells in all spermatogenesis stages, even in sexually matures individuals. Sperms are released from testicles in bundles with up to 32 cells. These bundles are gradually disorganized inside seminal vesicle, witch have a fold that we believe that play a role like a valve, dosing sperms released in each ejaculation. In T. lactitarse, mating occurs before each oviposition what can assure male paternity of most offspring in that nest, since spermatheca is practically vestigial in these females and then might disable sperm storage. Otherwise in T. nitidum mating is less common and there is sperm inside spermatheca, although it is a little amount. This suggests that there are differences in reproductive strategies between both species. / O aparelho reprodutor masculino de Trypoxylon (Trypargilum) apresenta o padrão básico para os Hymenoptera, mas com variações morfológicas capazes de caracterizar o subgênero. Ele é formado por dois testículos, dois ductos deferentes e um ducto ejaculatório. Em cada ducto deferente há uma região diferenciada em vesícula seminal e desemboca uma glândula acessória. Cada testículo possui três folículos, os quais apresentam células germinativas nas diferentes fases da espermatogênese, mesmo em machos sexualmente maduros. Os espermatozóides deixam os testículos em feixes de até 32 espermatozóides. Esses feixes são gradualmente desfeitos nas vesículas seminais. Estas apresentam uma dobra que parece funcionar como uma válvula, dosando os espermatozóides liberados em cada ejaculação. Em T. lactitarse ocorrem cópulas antes de cada oviposição, o que pode garantir ao macho guarda a paternidade da maior parte da progênie feminina daquele ninho, já que a espermateca da fêmea é praticamente vestigial e, assim, deve impossibilitar o armazenamento de espermatozóides. Diferentemente, em T. nitidum as cópulas são menos freqüentes e há espermatozóides na espermateca, apesar de em pequena quantidade. Isso sugere que pode haver diferenças nas estratégias reprodutivas entre essas duas espécies.
7

Desenvolvimento das espermatecas durante o estágio pupal de Aedes aegypti / Spermathecal development during the pupation of the yellow fever mosquito Aedes aegypti

Pascini, Tales Vicari 25 July 2014 (has links)
Made available in DSpace on 2015-03-26T13:30:52Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1364719 bytes, checksum: e98a1c4f2c50911557ec7ffc6fdc02dd (MD5) Previous issue date: 2014-07-25 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / In general, culicid females copulate once and store sperm in one or more structures in their reproductive system named spermathecae. In Aedes aegypti, the sperm are stored during the female reproductive period into three spermathecae and are supposedly maintained by the spermathecal glandular secretions. Despite the A. aegypti spermathecae is well characterized, its development is still unknown. The present work studied the A. aegypti spermathecal development during the pupation. During the development of A. aegypti spermatheca, no morphological changes, such as those described in Drosophila melanogaster. In white pupa (just after pupation), the spermathecal primordia appears as a tiny structure that grows rapidly after 24 hours of pupation. After 48 hours of pupation, we can see the espermatecal gland, reservoir cuticular deposition and the presence of a flocculent secretion into the espermatecal duct lumen. Within 72 hours of pupation, we observe again an increase in the volume of spermathecal reservoir, this showing its cuticle layers and the same flocculent material found in the previously. This flocculent material/secretion in the early stages of development seems to assist in the spermathecal lumen development, which happens at the same time of the cuticular deposition. We have observed cell death, a process that seems to provide space for the neighbor cells to grow. Microvilli were observed in all analised periods in epithelial and glandular cells, which seems to be related to the cuticle components production by the epithelial cells or the substances secreted into the reservoir lumen through spermathecal gland. The temporal difference in the development of the reservoir and the duct (which was also observed in other insects) may happens because the espermatecal duct is formed earlier than the reservoir. In newly-emerged females, the spermathecae are already completely formed with reservoir, gland cells and duct with a thick cuticular layer and a large amount of flocculent secretion into the lumen. This secretion is believed to be originated from glandular cells to provide the essential conditions for guiding, allocating and maintaining the sperm. / As fêmeas dos culicídeos copulam uma única vez e são capazes de armazenar espermatozoides em um ou mais órgão(s) do sistema reprodutor denominado(s) espermateca(s). Em Aedes aegypti os espermatozoides são mantidos no interior de suas três espermatecas graças às secreções das glândulas espermatecais desse órgão. Apesar das espermatecas de A. aegypti serem bem caracterizadas, seu processo de desenvolvimento ainda é desconhecido. No presente trabalho estudamos o desenvolvimento das espermatecas ao longo da pupação, a partir do período de pupa branca até a fase adulta. Durante o desenvolvimento espermatecal não se observou alterações morfológicas como as descritas para Drosophila melanogaster, há somente um aumento de volume das células e crescimento de suas estruturas constituintes, possibilitando o rápido desenvolvimento desse órgão. No início da pupação (o estágio de pupa branca), a espermateca se apresenta como uma estrutura diminuta, que rapidamente cresce após 24 horas. Em 48 horas de pupação, se observa a glândula espermatecal, a deposição cuticular no reservatório e a presença de uma secreção com aspecto floculento, no lúmen do ducto espermatecal. Com 72 horas de pupação, observa-se novamente um aumento no volume do reservatório espermatecal, esse apresentando cutícula com todas as suas camadas formadas e o interior dos ductos das células glandulares repletos desse mesmo material floculento encontrado no período anterior. A presença desse material nos períodos iniciais de desenvolvimento parece promover a abertura do espaço onde vai ser formado o lúmen do ducto e do reservatório, que posteriormente vai sofrer o processo de deposição cuticular. Foram observadas algumas células em processo de morte celular. Há ainda, a presença de microvilosidades nas células epiteliais e nas células glandulares em todos os períodos analisados, que parece estar relacionada seja para a produção dos componentes para a formação da cutícula pelo epitélio ou no processo de secreção de substâncias lançadas no interior do lúmen do reservatório pela glândula espermatecal. Observou-se ainda, uma diferença temporal na estruturação entre o reservatório e o ducto espermatecal, que também foi observada em Tenebrio molitor e em D. melanogaster, o que pode ser pelo fato de o ducto espermatecal ser formado antes do reservatório. Já nas fêmeas recém- emergidas, a espermateca apresenta seu reservatório, glândula e ducto espermatecal completamente formados, com uma espessa camada cuticular e uma grande quantidade de material floculento e elétron-denso, que se acredita ser originado para fornecer as condições essenciais para a condução, alocação e manutenção da viabilidade dos espermatozoides em seu interior.

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