Pedipalp

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Bichuette, Maria Elina - One of the best experts on this subject based on the ideXlab platform.

Do Monte, Bruno Gabriel - One of the best experts on this subject based on the ideXlab platform.

Von Schimonsky Diego - One of the best experts on this subject based on the ideXlab platform.

Gallão, Jonas Eduardo - One of the best experts on this subject based on the ideXlab platform.

Alfredo V. Peretti - One of the best experts on this subject based on the ideXlab platform.

  • Patterns of Sperm Transfer Behavior in a Pholcid Spider with Two Distinct Copulatory Phases
    Journal of Insect Behavior, 2018
    Co-Authors: Franco Cargnelutti, Lucia Calbacho-rosa, Alex Córdoba-aguilar, Alfredo V. Peretti
    Abstract:

    Sexual selection is the responsible force for the evolution and maintenance of genital diversity and function. This is the case for example, of genital movements performed by males during mating and copulation duration. Spiders perform ritualized copulations whereby males carry out different types of movements using their Pedipalps with varying duration. The function and duration of these Pedipalp movements is unclear. In the pholcid spider, Holocnemus pluchei males that copulate with virgin females perform two copulatory phases: phase I in which the Pedipalps move and phase II in which Pedipalps remain motionless. Using H. pluchei as a study species, our study aims were: 1) to assess if sperm transfer occurs when Pedipalps move or are still and quantify the number of sperm in male bulbs and in the female uterus externus after copulation; and, 2) to determine if amount of sperm transferred to females is associated with duration of each copulatory phase. Two experimental groups (i. e. complete copulation and interrupted copulation) were established in which the amount of sperm remaining in the male bulbs and the amount of sperm stored by females were determined. Our results show that sperm transfer occurs during phase I, that males transfer almost all sperm from their bulbs while the females store only 20% of that male amount. There was no relation between the amount of sperm transferred or stored and the duration of the copulatory phases. These results support the hypothesis that while both phases may serve a copulatory courtship, only phase I (when Pedipalps move) serves for sperm transfer.

  • Copulatory behavior in a pholcid spider: males use specialized genitalic movements for sperm removal and copulatory courtship
    Naturwissenschaften, 2013
    Co-Authors: Lucia Calbacho-rosa, Alex Córdoba-aguilar, Ivette Galicia-mendoza, María Sofía Dutto, Alfredo V. Peretti
    Abstract:

    Sexual selection may operate on pre-copulatory, copulatory, and post-copulatory traits. An example of a copulatory target of sexual selection is the genitalic movements a male performs during copulation. These movements may function either to prevent sperm competition or to influence a female’s fertilization decision. Here we investigated how copulation duration, Pedipalp movements, and abdominal movements that males of the pholcid spider Holocnemus pluchei produce during copulation influence sperm removal and/or patterns of successful sperm transfer. We compared mating events with virgin and mated females for differences in copulatory and post-copulatory behavior. We expected longer copulation duration, longer Pedipalp movement duration, and more complex and frequent Pedipalp and abdominal movements when males mated with mated females compared to virgin females. Except for abdominal movements, our results corroborated these predictions. Furthermore, when we investigated mating events with mated females, we observed sperm mass ejection from the female gonopore and physical removal of sperm by males’ procursi. Females with interrupted second mating events showed a significant reduction of stored sperm masses compared to females with completed mating events. We suggest that males use alternating Pedipalp movements to remove most of the rival sperm stored by mated females prior to sperm transfer. Copulation duration and Pedipalp movements can be further used to transfer sperm and/or as a form of genitalic copulatory courtship.

  • Behavioral roles of the sexually dimorphic structures in the male harvestman, Phalangium opilio (Opiliones, Phalangiidae)
    Canadian Journal of Zoology, 2006
    Co-Authors: Rodrigo Hirata Willemart, Jean-pierre Farine, Alfredo V. Peretti, Pedro Gnaspini
    Abstract:

    Abstract: In various animal species, male sexual dimorphic characters may be used during intrasexual contests as ornaments to attract females, or to hold them before, during, or after copulation. In the well-known harvestman, Phalangium opilio L., 1758, the behavioral functions of these male sexually dimorphic structures have never been studied in detail. Therefore, in addition to a morphometric study, 21 male contests and 43 sexual interactions were analyzed. Our observations revealed that during contests, the male cheliceral horns form a surface by which the contestants use to push each other face-to-face while rapidly tapping their long Pedipalps against the Pedipalps of the opponent, occasionally twisting the opponent's Pedipalp. Scanning electron micrographs revealed contact mechanoreceptors on the Pedipalp that would detect the intensity–frequency of contact with the contender's Pedipalp. Larger males won almost all contests, whereas the loser rapidly fled. During sexual interactions, the longer Pedipalps of the male held legs IV of the female, whereas males with shorter Pedipalps held the female by legs III. No contact with the male Pedipalps and chelicerae by the females was visible before, during, or after copulation. Soon after copulating, males typically bent over the female, positioning their cheliceral horns against the females's dorsum. Consequently, our data show that the cheliceral horns and the longer Pedipalps of the male seem to play an important role, during both intersexual and intrasexual encountering. Resume : Chez de nombreuses especes animales, les ornementations sexuellement dimorphiques des mâles peuvent etre utilisees lors des combats rituels entre mâles ou comme signal afin d'attirer les femelles ou les retenir avant, pendant et apres l'accouplement. Chez l'opilion Phalangium opilio L., 1758, le role precis joue par ces structures n'a jamais ete mis en evidence. Au cours de ce travail, outre une etude morphometrique, nous avons analyse, grâce a des enregistrements video, 21 combats entre mâles et 43 accouplements. Nous avons pu montrer que, lors des combats, les mâles utilisent les cornes portees par les cheliceres pour se repousser lorsqu'ils sont face-a-face, tout en se tapant mutuellement a l'aide de leurs longs Pedipalpes, voire en les enroulant avec ceux de l'adversaire. Des micrographies realisees au microscope electronique a balayage revelent l'existence de mecanorecepteurs sur les Pedipalpes qui pourraient permettre au mâle de detecter la frequence et l'intensite des contacts des Pedipalpes de son adversaire. Les mâles les plus grands gagnent presque tous les combats, le perdant fuyant rapidement. Au cours du comportement sexuel, les mâles a grands Pedipalpes les utilisent pour agripper les pattes IV de la femelle, alors que les mâles a Pedipalpes plus courts les retiennent par les pattes III. Il n'y a aucun contact tactile de la part des femelles avec les Pedipalpes et les cheliceres des mâles avant, pendant et apres l'accouplement. Juste apres l'accouplement, le mâle s'appuie sur le dos de la femelle a l'aide des cornes de ses cheliceres. D'apres nos observations, il semble donc que les cheliceres et les longs Pedipalpes des mâles jouent un role non negligeable lors des interactions intra- et inter-sexuelles chez cette espece.

  • Behavioral roles of the sexually dimorphic structures in the male harvestman, Phalangium opilio (Opiliones, Phalangiidae)
    Canadian Journal of Zoology, 2006
    Co-Authors: Rodrigo Hirata Willemart, Jean-pierre Farine, Alfredo V. Peretti, Pedro Gnaspini
    Abstract:

    Abstract: In various animal species, male sexual dimorphic characters may be used during intrasexual contests as ornaments to attract females, or to hold them before, during, or after copulation. In the well-known harvestman, Phalangium opilio L., 1758, the behavioral functions of these male sexually dimorphic structures have never been studied in detail. Therefore, in addition to a morphometric study, 21 male contests and 43 sexual interactions were analyzed. Our observations revealed that during contests, the male cheliceral horns form a surface by which the contestants use to push each other face-to-face while rapidly tapping their long Pedipalps against the Pedipalps of the opponent, occasionally twisting the opponent's Pedipalp. Scanning electron micrographs revealed contact mechanoreceptors on the Pedipalp that would detect the intensity–frequency of contact with the contender's Pedipalp. Larger males won almost all contests, whereas the loser rapidly fled. During sexual interactions, the longer Pedipalps of the male held legs IV of the female, whereas males with shorter Pedipalps held the female by legs III. No contact with the male Pedipalps and chelicerae by the females was visible before, during, or after copulation. Soon after copulating, males typically bent over the female, positioning their cheliceral horns against the females's dorsum. Consequently, our data show that the cheliceral horns and the longer Pedipalps of the male seem to play an important role, during both intersexual and intrasexual encountering. Résumé : Chez de nombreuses espèces animales, les ornementations sexuellement dimorphiques des mâles peuvent être utilisées lors des combats rituels entre mâles ou comme signal afin d'attirer les femelles ou les retenir avant, pendant et après l'accouplement. Chez l'opilion Phalangium opilio L., 1758, le rôle précis joué par ces structures n'a jamais été mis en évidence. Au cours de ce travail, outre une étude morphométrique, nous avons analysé, grâce à des enregistrements vidéo, 21 combats entre mâles et 43 accouplements. Nous avons pu montrer que, lors des combats, les mâles utilisent les cornes portées par les chélicères pour se repousser lorsqu'ils sont face-à-face, tout en se tapant mutuellement à l'aide de leurs longs pédipalpes, voire en les enroulant avec ceux de l'adversaire. Des micrographies réalisées au microscope électronique à balayage révèlent l'existence de mécanorécepteurs sur les pédipalpes qui pourraient permettre au mâle de détecter la fréquence et l'intensité des contacts des pédipalpes de son adversaire. Les mâles les plus grands gagnent presque tous les combats, le perdant fuyant rapidement. Au cours du comportement sexuel, les mâles à grands pédipalpes les utilisent pour agripper les pattes IV de la femelle, alors que les mâles à pédipalpes plus courts les retiennent par les pattes III. Il n'y a aucun contact tactile de la part des femelles avec les pédipalpes et les chélicères des mâles avant, pendant et après l'accouplement. Juste après l'accouplement, le mâle s'appuie sur le dos de la femelle à l'aide des cornes de ses chélicères. D'après nos observations, il semble donc que les chélicères et les longs pédipalpes des mâles jouent un rôle non négligeable lors des interactions intra- et inter-sexuelles chez cette espèce.

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