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Izquierdo MA, Dederichs TM, Cargnelutti F, Michalik P. Copulatory behaviour and genital mechanics suggest sperm allocation by a non-intromittent sclerite in a pholcid spider. ROYAL SOCIETY OPEN SCIENCE 2023; 10:230263. [PMID: 37266042 PMCID: PMC10230183 DOI: 10.1098/rsos.230263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 05/02/2023] [Indexed: 06/03/2023]
Abstract
The male genitalia of pholcid spiders, which is one of the most species-rich spider families, are characterized by a procursus, which is a morphologically diverse projection of the copulatory organ. It has been shown that the procursus interacts with the female genitalia during copulation. Here, we investigate the function of the procursus in Gertschiola neuquena, a species belonging to the early branched and understudied subfamily Ninetinae, using behavioural and morphological data. Although many aspects of the copulatory behaviour of G. neuquena follow the general pattern described for the family, males use only one pedipalp during each copulation. Based on our micro-CT analysis of cryofixed mating pairs using virgin females, we can show that the long and filiform procursus is inserted deeply into the unpaired convoluted female spermatheca, and the intromittent sclerite, the embolus, is rather short and stout only reaching the most distal part of the female sperm storage organ. Histological data revealed that sperm are present in the most proximal part of the spermatheca, suggesting that the procursus is used to allocate sperm deeply into the female sperm storage organ. This represents the first case of a replacement of the sperm allocation function of the intromittent sclerite in spiders.
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Affiliation(s)
- M. A. Izquierdo
- Facultad de Ciencias Exactas, Físicas y Naturales, Departamento de Diversidad Biológica y Ecología, Universidad Nacional de Córdoba, Córdoba, 5000, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Laboratorio de Biología Reproductiva y Evolución, Instituto de Diversidad y Ecología Animal (IDEA), Córdoba, 5000, Argentina
| | - T. M. Dederichs
- Universität Greifswald, Zoologisches Institut und Museum, Loitzer Straße 26, 17489 Greifswald, Germany
| | - F. Cargnelutti
- Facultad de Ciencias Exactas, Físicas y Naturales, Departamento de Diversidad Biológica y Ecología, Universidad Nacional de Córdoba, Córdoba, 5000, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Laboratorio de Biología Reproductiva y Evolución, Instituto de Diversidad y Ecología Animal (IDEA), Córdoba, 5000, Argentina
| | - P. Michalik
- Universität Greifswald, Zoologisches Institut und Museum, Loitzer Straße 26, 17489 Greifswald, Germany
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Sentenská L, Scott C, Mouginot P, Andrade MCB. OUP accepted manuscript. Behav Ecol 2022; 33:688-697. [PMID: 35812367 PMCID: PMC9262164 DOI: 10.1093/beheco/arac023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 02/13/2022] [Accepted: 04/11/2022] [Indexed: 11/14/2022] Open
Abstract
Understanding factors affecting male mate choice can be important for tracking the dynamics of sexual selection in nature. Male brown widow spiders (Latrodectus geometricus) mate with adult as well as immature (subadult) females. Mating with adults involves costly courtship with a repertoire of signaling behaviors, and typically ends with cannibalism (“self-sacrifice” initiated by male somersault). Mating with subadults involves brief courtship with behavioral repertoire reduced to one component (vibration) and no cannibalism. We examined male mate choice as a function of risks associated with different types of mates and the cues available to courting males. Previous studies showed male preference for adults based on air-borne pheromones, but it was unclear whether that preference is maintained after males reach female’s webs. We show that males prefer adults also based on silk-borne contact cues. To determine which types of cues trigger different courtship components, we swapped adults and subadults between webs. We showed that contact with adult females’ webs triggers two courtship behaviors from the repertoire, with adult female’s bodies triggering additional behaviors. However, vibrational signals occur regardless of the web origin or female developmental stage. We conclude that males recognize subadult females as potential mates, but are more likely to invest in costly courtship behaviors and mating attempts with adults. In our experiments, subadults were less likely to mate than adults. We conclude that mating with adults could be the preferred option for males because of the higher likelihood of copulation, even at the cost of a higher risk of cannibalism.
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Affiliation(s)
| | - Catherine Scott
- Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, Ontario, Canada
| | - Pierick Mouginot
- PSL Université Paris: EPHE-UPVD-CNRS, USR 3278 CRIOBE, Université de Perpignan, 52 Avenue Paul Alduy, CEDEX 9, 66860 Perpignan, France
| | - Maydianne C B Andrade
- Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, Ontario, Canada
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Juvenile Experience with Male Cues Triggers Cryptic Choice Mechanisms in Adult Female Redback Spiders. INSECTS 2021; 12:insects12090825. [PMID: 34564265 PMCID: PMC8468702 DOI: 10.3390/insects12090825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 09/05/2021] [Accepted: 09/06/2021] [Indexed: 11/23/2022]
Abstract
Simple Summary Females of many species vary in their receptivity to male mating attempts. When many males are present in the habitat, the theory predicts that females should be choosy and discriminate among potential mates. When few males are available, females should mate readily with the first male who courts, and thus avoid the risk of remaining unmated. We predicted that cues perceived as juveniles that indicate male availability would affect the mating behaviour of adult females. In our first experiment, juvenile females were exposed to airborne chemicals produced by males at high or low densities. In our second experiment, we mimicked a natural situation where males or other juveniles live on the webs of females shortly before they become sexually mature, and compared this to females developing in isolation. As was consistent with our predictions, we found that the adult females changed their behaviour after exposure to cues of high male availability during development. When the females perceived many males nearby (high density airborne cues or living with males) they more often interrupted copulation, or cannibalized the males before the mating was complete as adults. In comparison, when the cues indicated low male availability, the adult females were more likely to allow the males to complete mating, and cannibalism was less common. Abstract Female choice may be linked to population density if the expected encounter rates with potential mates affects choosiness (the energy and risk engaged to express mate preferences). Choosiness should covary with male availability, which could be assessed using the social cues available during development. We tested whether the exposure of juvenile females to cues of male density affected the mechanisms of choosiness of adult Latrodectus hasselti spiders in two experiments simulating natural contexts. The juvenile females were exposed to (1) volatile chemicals from two densities of adult males (airborne cues), and (2) tactile, vibrational and chemical cues from adult males or other females (cohabitation cues). As adults, the females mated readily, regardless of the treatment, but there was strong evidence for post-copulatory mechanisms of choosiness in females exposed to cues of high male availability. These included abbreviated matings (in both experiments), cannibalism of the males before the mating was complete (cohabitation), and, remarkably, a reduction in the successful placement of internal sperm plugs (cohabitation). These shifts decrease the likelihood that the first mate would monopolize paternity if the female chose to mate again. We conclude that female choosiness may impose a strong selection on males despite the high mating rates, and these effects can hinge on the cues of male availability detected by juveniles.
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Sentenská L, Neumann A, Lubin Y, Uhl G. Functional morphology of immature mating in a widow spider. Front Zool 2021; 18:19. [PMID: 33902650 PMCID: PMC8074507 DOI: 10.1186/s12983-021-00404-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 03/28/2021] [Indexed: 11/10/2022] Open
Abstract
Background Mating generally occurs after individuals reach adulthood. In many arthropods including spiders, the adult stage is marked by a final moult after which the genitalia are fully developed and functional. In several widow spider species (genus Latrodectus), however, immature females may mate a few days before they moult to adulthood, i.e. in their late-subadult stage. While the “adult” mating typically results in cannibalism, males survive the “immature” mating. During both “immature” and “adult” matings, males leave parts of their paired copulatory organs within female genitalia, which may act as mating plugs. To study potential costs and benefits of the two mating tactics, we investigated female genital morphology of the brown widow spider, L. geometricus. Light microscopy, histology and micro-computed tomography of early-subadult, late-subadult and adult females were conducted to determine the overall pattern of genital maturation. We compared genitalia of mated late-subadult and adult females to reveal potential differences in the genitalic details that might indicate differential success in sperm transfer and different environments for sperm storage and sperm competition. Results We found that the paired sperm storage organs (spermathecae) and copulatory ducts are developed already in late-subadult females and host sperm after immature mating. However, the thickness of the spermathecal cuticle and the staining of the secretions inside differ significantly between the late-subadult and adult females. In late-subadult females mating plugs were found with higher probability in both spermathecae compared to adult females. Conclusions Sperm transfer in matings with late-subadult females follows the same route as in matings with adult females. The observed differences in the secretions inside the spermathecae of adult and late-subadult females likely reflect different storage conditions for the transferred sperm which may lead to a disadvantage under sperm competition if the subadult female later re-mates with another male. However, since males mating with late-subadult females typically transfer sperm to both spermathecae they might benefit from numerical sperm competition as well as from monopolizing access to the female sperm storage organs. The assessment of re-mating probability and relative paternity will clarify the costs and benefits of the two mating tactics in light of these findings. Supplementary Information The online version contains supplementary material available at 10.1186/s12983-021-00404-1.
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Affiliation(s)
- Lenka Sentenská
- Department of General and Systematic Zoology, University of Greifswald, Loitzer Strasse 26, 17489, Greifswald, Germany. .,Department of Biological Sciences, University of Toronto Scarborough, Scarborough, Ontario, Canada.
| | - Aileen Neumann
- Department of General and Systematic Zoology, University of Greifswald, Loitzer Strasse 26, 17489, Greifswald, Germany
| | - Yael Lubin
- Mitrani Department of Desert Ecology, Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, Israel
| | - Gabriele Uhl
- Department of General and Systematic Zoology, University of Greifswald, Loitzer Strasse 26, 17489, Greifswald, Germany
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Tuni C, Schneider J, Uhl G, Herberstein ME. Sperm competition when transfer is dangerous. Philos Trans R Soc Lond B Biol Sci 2020; 375:20200073. [PMID: 33070729 DOI: 10.1098/rstb.2020.0073] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Aggressive and cannibalistic female spiders can impose strong selection on male mating and fertilization strategies. Furthermore, the distinctive reproductive morphology of spiders is predicted to influence the outcome of sperm competition. Polyandry is common in spiders, leading to defensive male strategies that include guarding, plugging and self-sacrifice. Paternity patterns are highly variable and unlikely to be determined solely by mating order, but rather by relative copulation duration, deployment of plugs and cryptic female choice. The ability to strategically allocate sperm is limited, either by the need to refill pedipalps periodically or owing to permanent sperm depletion after mating. Further insights now rely on unravelling several proximate mechanisms such as the process of sperm activation and the role of seminal fluids. This article is part of the theme issue 'Fifty years of sperm competition'.
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Affiliation(s)
- Cristina Tuni
- Department of Biology II, Ludwig-Maximilians University of Munich, Planegg-Martinsried, Munich, Germany
| | - Jutta Schneider
- Institute of Zoology, University of Hamburg, Martin-Luther-King Platz 3, Hamburg 20146 Germany
| | - Gabriele Uhl
- General and Systematic Zoology, University of Greifswald, Bachstrasse 11/13, Greifswald 17489, Germany
| | - Marie E Herberstein
- Department of Biological Sciences, Macquarie University, North Ryde, Sydney NSW 2109, Australia
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Emberts Z, Escalante I, Bateman PW. The ecology and evolution of autotomy. Biol Rev Camb Philos Soc 2019; 94:1881-1896. [PMID: 31240822 DOI: 10.1111/brv.12539] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 05/29/2019] [Accepted: 06/04/2019] [Indexed: 01/29/2023]
Abstract
Autotomy, the self-induced loss of a body part, occurs throughout Animalia. A lizard dropping its tail to escape predation is an iconic example, however, autotomy occurs in a diversity of other organisms. Octopuses can release their arms, crabs can drop their claws, and bugs can amputate their legs. The diversity of organisms that can autotomize body parts has led to a wealth of research and several taxonomically focused reviews. These reviews have played a crucial role in advancing our understanding of autotomy within their respective groups. However, because of their taxonomic focus, these reviews are constrained in their ability to enhance our understanding of autotomy. Here, we aim to synthesize research on the ecology and evolution of autotomy throughout Animalia, building a unified framework on which future studies can expand. We found that the ability to drop an appendage has evolved multiple times throughout Animalia and that once autotomy has evolved, selection appears to act on the removable appendage to increase the efficacy and/or efficiency of autotomy. This could explain why some autotomizable body parts are so elaborate (e.g. brightly coloured). We also show that there are multiple benefits, and variable costs, associated with autotomy. Given this variation, we generate an economic theory of autotomy (modified from the economic theory of escape) which makes predictions about when an individual should resort to autotomy. Finally, we show that the loss of an autotomizable appendage can have numerous consequences on population and community dynamics. By taking this broad taxonomic approach, we identified patterns of autotomy that transcend specific lineages and highlight clear directions for future research.
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Affiliation(s)
- Zachary Emberts
- Department of Biology, University of Florida, 876 Newell Drive, Gainesville, FL, 32611, USA
| | - Ignacio Escalante
- Department of Environmental Sciences, Policy, & Management, University of California, 140 Mulford Hall, Berkeley, CA, 94720, USA
| | - Philip W Bateman
- Behavioural Ecology Lab, School of Molecular and Life Sciences, Curtin University, Perth, WA, 6845, Australia
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8
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Andrade MC. Sexual selection and social context: Web-building spiders as emerging models for adaptive plasticity. ADVANCES IN THE STUDY OF BEHAVIOR 2019. [DOI: 10.1016/bs.asb.2019.02.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Sentenská L, Pekár S, Uhl G. Deposition, removal and production site of the amorphous mating plug in the spider Philodromus cespitum. Naturwissenschaften 2018; 105:50. [PMID: 30030630 DOI: 10.1007/s00114-018-1575-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 06/28/2018] [Accepted: 07/06/2018] [Indexed: 10/28/2022]
Abstract
In order to avoid sperm competition, males of many taxa apply physical barriers, so-called mating plugs, into female genitalia. Females may control which males deposit a plug through pre-copulatory mate choice or by influencing plug efficacy to avoid costs imposed by plugging. However, subsequent suitors might remove the plugs. We investigated behavioural and morphological aspects of plug deposition and removal in a promiscuous spider, Philodromus cespitum (Philodromidae). We performed mating trials to investigate factors affecting plugging. To identify the plug origin, we conducted a morphological analysis using 3D X-ray microtomography and histology of the male copulatory organ and the female genital tract. In P. cespitum, the plug material is produced in the male genital bulb and transferred to the female together with sperm. The copulation is brief and terminated by the female. After mating, plugging material was found in the genital atrium of all females, covering it to a varying degree (10-100%). The extent of coverage was associated with the duration of movements of male copulatory organ connected with sperm transfer (i.e. full haematodochal expansions) and with the number of taps a male delivered with his legs to the female during courtship. Males larger than the female performed more tapping movements. Mating trials with plugged females revealed that males could remove plugs partly or entirely. Removal success increased with increasing foreleg length ratio between the male who removed the plug and the one who deposited it. We discuss our results in the light of the potential female control of plug deposition and removal.
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Affiliation(s)
- Lenka Sentenská
- Department of Botany and Zoology, Masaryk University, Brno, Czech Republic.
| | - Stano Pekár
- Department of Botany and Zoology, Masaryk University, Brno, Czech Republic.
| | - Gabriele Uhl
- Zoological Institute and Museum, Department of General and Systematic Zoology, University of Greifswald, Greifswald, Germany.
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Biaggio MD, Sandomirsky I, Lubin Y, Harari AR, Andrade MCB. Copulation with immature females increases male fitness in cannibalistic widow spiders. Biol Lett 2017; 12:rsbl.2016.0516. [PMID: 27651535 DOI: 10.1098/rsbl.2016.0516] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 08/23/2016] [Indexed: 11/12/2022] Open
Abstract
Copulatory cannibalism of male 'widow' spiders (genus Latrodectus) is a model example of the extreme effects of sexual selection, particularly in L. hasselti and L. geometricus where males typically facilitate cannibalism by females and mate only once. We show that these males can increase their reproductive success by copulating with final-instar, immature females after piercing the female's exoskeleton to access her newly developed sperm storage organs. Females retain sperm through their final moult and have similar fecundity to adult-mated females. This is an adaptive male tactic because immature mating increases insemination success relative to adult mating (which predicts higher paternity) and moreover, rarely ends in cannibalism, so males can mate again. Although successful only during a brief period before the female's final moult, males may employ this tactic when they associate with final-instar females in nature. Consistent with this, one-third of L. hasselti females collected as immatures in nature were already mated. Immature mating alters sexual selection on these otherwise monogynous males, and may explain male traits allowing facultative polygyny in Latrodectus Since male cohabitation with immature females is common among invertebrates, immature mating may be a widespread, previously unrecognized mating tactic, particularly when unmated females are of high reproductive value.
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Affiliation(s)
- M Daniela Biaggio
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Canada M1C1A4 Department of Ecology and Evolutionary Biology, University of Toronto Scarborough, Toronto, Canada M1C1A4
| | - Iara Sandomirsky
- Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, Beersheba 8499000, Israel
| | - Yael Lubin
- Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, Beersheba 8499000, Israel
| | - Ally R Harari
- Department of Entomology, Volcani Center, Bet Dagan 50250, Israel
| | - Maydianne C B Andrade
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Canada M1C1A4 Department of Ecology and Evolutionary Biology, University of Toronto Scarborough, Toronto, Canada M1C1A4
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Emberts Z, Miller CW, Kiehl D, St Mary CM. Cut your losses: self-amputation of injured limbs increases survival. Behav Ecol 2017; 28:1047-1054. [PMID: 29622925 PMCID: PMC5873245 DOI: 10.1093/beheco/arx063] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 03/24/2017] [Accepted: 04/04/2017] [Indexed: 11/17/2022] Open
Abstract
Autotomy, self-induced limb loss, is an extreme trait observed throughout the animal kingdom; lizards drop their tails, crickets release their legs, and crabs drop their claws. These repeated evolutionary origins suggest that autotomy is adaptive. Yet, we do not have a firm understanding of the selective pressures that promote and maintain this extreme trait. Although multiple adaptive hypotheses exist, research has generally focused on autotomy’s adaptive value as a form of predator escape. However, autotomy could also be selected to reduce the cost of an injured limb, which we investigate here. Previously, this alternative hypothesis has been challenging to directly test because when an injury occurs on an autotomizable limb, that limb is almost always dropped (i.e., autotomy is behaviorally fixed within populations). Recently, however, we have identified a species, Narnia femorata (Insecta: Hemiptera: Coreidae), where some individuals autotomize limbs in response to injury, but some do not. This natural variation allowed us to investigate both the survival costs of retaining an injured limb and the benefits of autotomizing it. In this study, we find a positive association between autotomizing injured limbs and survival, thereby quantifying a new and likely widespread benefit of autotomy—reducing the cost of injury.
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Affiliation(s)
- Zachary Emberts
- Department of Biology, University of Florida, 876 Newell Drive Gainesville, FL 32611, USA
| | - Christine W Miller
- Entomology and Nematology Department, University of Florida, 1881 Natural Area Drive Gainesville, FL 32611, USA
| | - Daniel Kiehl
- Department of Biology, University of Florida, 876 Newell Drive Gainesville, FL 32611, USA
| | - Colette M St Mary
- Department of Biology, University of Florida, 876 Newell Drive Gainesville, FL 32611, USA
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Schütz D, Tschirren L, Pachler G, Grubbauer P, Taborsky M. Sperm-limited males save ejaculates for future matings when competing with superior rivals. Anim Behav 2017. [DOI: 10.1016/j.anbehav.2016.12.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Boisseau RP, Wilder SM, Barry KL. Sexual and nonsexual cannibalism have different effects on offspring performance in redback spiders. Behav Ecol 2016. [DOI: 10.1093/beheco/arw159] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Schneider MR, Mangels R, Dean MD. The molecular basis and reproductive function(s) of copulatory plugs. Mol Reprod Dev 2016; 83:755-767. [PMID: 27518218 DOI: 10.1002/mrd.22689] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 08/10/2016] [Indexed: 12/12/2022]
Abstract
In many animals, male ejaculates coagulate to form what has been termed a copulatory plug, a structure that varies in size and shape but often fills and seals the female's reproductive tract. The first published observation of a copulatory plug in a mammal was made more than 160 years ago, and questions about its formation and role in reproduction continue to endear evolutionary and population geneticists, behavioral ecologists, and molecular, reproductive, and developmental biologists alike. Here, we review the current knowledge of copulatory plugs, focusing on rodents and asking two main questions: how is it formed and what does it do? An evolutionary biology perspective helps us understand the latter, potentially leading to insights into the selective regimes that have shaped the diversity of this structure. Mol. Reprod. Dev. 83: 755-767, 2016 © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
| | - Rachel Mangels
- Molecular and Computational Biology, University of Southern California, Los Angeles, California
| | - Matthew D Dean
- Molecular and Computational Biology, University of Southern California, Los Angeles, California.
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16
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Neumann R, Schneider JM. Socially cued developmental plasticity in web-building spiders. BMC Evol Biol 2016; 16:170. [PMID: 27561330 PMCID: PMC5000426 DOI: 10.1186/s12862-016-0736-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 08/08/2016] [Indexed: 01/16/2023] Open
Abstract
Background Socially cued anticipatory plasticity (SCAP) has been proposed as a widespread mechanism of adaptive life-history shifts in semelparous species with extreme male mating investment. Such mating systems evolved several times independently in spiders and male reproductive success should critically depend on timely maturation and rapid location of a receptive and, ideally, virgin female. We experimentally investigated socially cued anticipatory plasticity in two sympatric, closely related Nephila species that share many components of their mating systems, but differ in the degree to which male reproductive success depends on mating with virgin females. Juveniles of both species were reared either in the presence or absence of virgin female silk cues. We predicted strong selection on socially cued plasticity in N. fenestrata in which males follow a highly specialized terminal investment strategy, but expected a weaker plastic response in N. senegalensis in which males lost the ability to monopolize females. Results Contrary to our predictions, N. fenestrata males presented with virgin female silk cues did not mature earlier than siblings reared isolated from such cues. Males in N. senegalensis, however, showed a significant response to female cues and matured several days earlier than control males. Plastic adjustment of maturation had no effect on male size. Conclusions Our results indicate that a strong benefit of mating with virgins due to first male sperm priority does not necessarily promote socially cued anticipatory plasticity. We emphasize the bidirectional mode of developmental responses and suggest that this form of plasticity may not only yield benefits through accelerated maturation, but also by avoiding costs of precipitate maturation in the absence of female cues.
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Affiliation(s)
- Rainer Neumann
- Zoologisches Institut, Universität Hamburg, Martin-Luther-King-Platz 3, 20146, Hamburg, Germany.
| | - Jutta M Schneider
- Zoologisches Institut, Universität Hamburg, Martin-Luther-King-Platz 3, 20146, Hamburg, Germany
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17
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Assis BA, Foellmer MW. One size fits all? Determinants of sperm transfer in a highly dimorphic orb-web spider. J Evol Biol 2016; 29:1106-20. [DOI: 10.1111/jeb.12848] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 02/02/2016] [Indexed: 11/28/2022]
Affiliation(s)
- B. A. Assis
- Department of Biology; Adelphi University; 1 South Ave. Garden City NY 11530 USA
| | - M. W. Foellmer
- Department of Biology; Adelphi University; 1 South Ave. Garden City NY 11530 USA
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18
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Scott C, Kirk D, McCann S, Gries G. Web reduction by courting male black widows renders pheromone-emitting females' webs less attractive to rival males. Anim Behav 2015. [DOI: 10.1016/j.anbehav.2015.06.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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19
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Baruffaldi L, Andrade MC. Contact pheromones mediate male preference in black widow spiders: avoidance of hungry sexual cannibals? Anim Behav 2015. [DOI: 10.1016/j.anbehav.2015.01.007] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Neumann R, Schneider JM. Differential investment and size-related mating strategies facilitate extreme size variation in contesting male spiders. Anim Behav 2015. [DOI: 10.1016/j.anbehav.2014.12.027] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Sentenská L, Pekár S, Lipke E, Michalik P, Uhl G. Female control of mate plugging in a female-cannibalistic spider (Micaria sociabilis). BMC Evol Biol 2015; 15:18. [PMID: 25886749 PMCID: PMC4327802 DOI: 10.1186/s12862-014-0278-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 12/22/2014] [Indexed: 11/17/2022] Open
Abstract
Background Sperm competition imposes a strong selective pressure on males, leading to the evolution of various physiological, morphological and behavioral traits. Sperm competition can be prevented by blocking or impeding the access to female genitalia by means of a mating plug. We investigated the factors responsible for plug production and function in the promiscuous female-cannibalistic spider Micaria sociabilis (Gnaphosidae). Results We performed mating trials using females with and without a plug that consists of an amorphous mass. The mating trials demonstrated that the probability of male plugging increased non-linearly with the duration of copulation. Copulation duration and plug production seem to be controlled by the female. We found that females terminated matings later if males were fast at genital coupling. Whereas incomplete plugs had disappeared on the day following copulation, complete plugs persisted (40%). In matings with females with complete plugs, only a small proportion of males (7%) were able to remove the plug, indicating the high effectiveness of plugging. Moreover, males ceased attempts to copulate with plugged females with higher probability. 3D X-ray microscopy of the female and male genitalia showed that the plug material can extend far into the female genital tract and that the plug material is produced by a massive gland inside the palpal organ of the modified male pedipalps. Conclusions Our study demonstrates that the mating plug in M. sociabilis constitutes an effective male strategy to avoid sperm competition that seems to be under female control. Electronic supplementary material The online version of this article (doi:10.1186/s12862-014-0278-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Lenka Sentenská
- Department of Botany and Zoology, Masaryk University, Brno, Czech Republic.
| | - Stano Pekár
- Department of Botany and Zoology, Masaryk University, Brno, Czech Republic.
| | - Elisabeth Lipke
- Department of General and Systematic Zoology, Zoological Institute and Museum, Ernst Moritz Arndt University of Greifswald, Greifswald, Germany.
| | - Peter Michalik
- Department of General and Systematic Zoology, Zoological Institute and Museum, Ernst Moritz Arndt University of Greifswald, Greifswald, Germany.
| | - Gabriele Uhl
- Department of General and Systematic Zoology, Zoological Institute and Museum, Ernst Moritz Arndt University of Greifswald, Greifswald, Germany.
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Kuntner M, Agnarsson I, Li D. The eunuch phenomenon: adaptive evolution of genital emasculation in sexually dimorphic spiders. Biol Rev Camb Philos Soc 2014; 90:279-96. [PMID: 24809822 DOI: 10.1111/brv.12109] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Revised: 03/24/2014] [Accepted: 04/01/2014] [Indexed: 12/01/2022]
Abstract
Under natural and sexual selection traits often evolve that secure paternity or maternity through self-sacrifice to predators, rivals, offspring, or partners. Emasculation-males removing their genitals-is an unusual example of such behaviours. Known only in insects and spiders, the phenomenon's adaptiveness is difficult to explain, yet its repeated origins and association with sexual size dimorphism (SSD) and sexual cannibalism suggest an adaptive significance. In spiders, emasculation of paired male sperm-transferring organs - secondary genitals - (hereafter, palps), results in 'eunuchs'. This behaviour has been hypothesized to be adaptive because (i) males plug female genitals with their severed palps (plugging hypothesis), (ii) males remove their palps to become better fighters in male-male contests (better-fighter hypothesis), perhaps reaching higher agility due to reduced total body mass (gloves-off hypothesis), and (iii) males achieve prolonged sperm transfer through severed genitals (remote-copulation hypothesis). Prior research has provided evidence in support of these hypotheses in some orb-weaving spiders but these explanations are far from general. Seeking broad macroevolutionary patterns of spider emasculation, we review the known occurrences, weigh the evidence in support of the hypotheses in each known case, and redefine more precisely the particular cases of emasculation depending on its timing in relation to maturation and mating: 'pre-maturation', 'mating', and 'post-mating'. We use a genus-level spider phylogeny to explore emasculation evolution and to investigate potential evolutionary linkage between emasculation, SSD, lesser genital damage (embolic breakage), and sexual cannibalism (females consuming their mates). We find a complex pattern of spider emasculation evolution, all cases confined to Araneoidea: emasculation evolved at least five and up to 11 times, was lost at least four times, and became further modified at least once. We also find emasculation, as well as lesser genital damage and sexual cannibalism, to be significantly associated with SSD. These behavioural and morphological traits thus likely co-evolve in spiders. Emasculation can be seen as an extreme form of genital mutilation, or even a terminal investment strategy linked to the evolution of monogyny. However, as different emasculation cases in araneoid spiders are neither homologous nor biologically identical, and may or may not serve as paternity protection, the direct link to monogyny is not clear cut. Understanding better the phylogenetic patterns of emasculation and its constituent morphologies and behaviours, a clearer picture of the intricate interplay of natural and sexual selection may arise. With the here improved evolutionary resolution of spider eunuch behaviour, we can more specifically tie the evidence from adaptive hypotheses to independent cases, and propose promising avenues for further research of spider eunuchs, and of the evolution of monogyny.
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Affiliation(s)
- Matjaž Kuntner
- Institute of Biology, Scientific Research Centre, Slovenian Academy of Sciences and Arts, Novi Trg 2, 1000, Ljubljana, Slovenia; Centre for Behavioural Ecology & Evolution, College of Life Sciences, Hubei University, 368 Youyi Road, 430062, Wuhan, China; National Museum of Natural History, Smithsonian Institution, PO Box 37012, Washington, DC, 20013-7012, U.S.A
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Zimmer SM, Schneider JM, Herberstein ME. Can males detect the strength of sperm competition and presence of genital plugs during mate choice? Behav Ecol 2014. [DOI: 10.1093/beheco/aru045] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Simmons LW, Buzatto BA. Contrasting responses of pre- and post-copulatory traits to variation in mating competition. Funct Ecol 2014. [DOI: 10.1111/1365-2435.12211] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Leigh W. Simmons
- Centre for Evolutionary Biology; School of Animal Biology (M092); The University of Western Australia; Crawley 6009 Australia
| | - Bruno A. Buzatto
- Centre for Evolutionary Biology; School of Animal Biology (M092); The University of Western Australia; Crawley 6009 Australia
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Modanu M, Michalik P, Andrade MCB. Mating system does not predict permanent sperm depletion in black widow spiders. Evol Dev 2013; 15:205-12. [PMID: 23607304 DOI: 10.1111/ede.12034] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Variation in sperm production is strongly influenced by mating system across taxa. Recent work in spiders suggests that males of some species show termination of spermatogenesis before their adult molt and thus an inability to produce sperm after maturation. This permanent sperm depletion (PSD) has been hypothesized to co-occur with monogyny, genital mutilation, or sexual cannibalism because the maintenance of continual sperm supplies is not necessary for species where males can expect only one mating opportunity. Here we test this hypothesis in two congeners exhibiting genital mutilation: the sexually cannibalistic, monogynous Australian redback spider Latrodectus hasselti and the polygynous Western black widow Latrodectus hesperus. We report that PSD does not occur in adult males of either species, and show that males transfer sperm into their copulatory organs multiple times as adults. These data suggest evolutionary links between mating system and investment in sperm production may be more complex than currently appreciated.
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Affiliation(s)
- Maria Modanu
- Department of Neurobiology and Behavior, Cornell University, 215 Tower Road, Ithaca, NY 14853, USA.
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Kasumovic MM. The multidimensional consequences of the juvenile environment: towards an integrative view of the adult phenotype. Anim Behav 2013. [DOI: 10.1016/j.anbehav.2013.02.009] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Danielson-François A, Hou C, Cole N, Tso IM. Scramble competition for moulting females as a driving force for extreme male dwarfism in spiders. Anim Behav 2012. [DOI: 10.1016/j.anbehav.2012.07.018] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Kuntner M, Gregorič M, Zhang S, Kralj-Fišer S, Li D. Mating plugs in polyandrous giants: which sex produces them, when, how and why? PLoS One 2012; 7:e40939. [PMID: 22829900 PMCID: PMC3400571 DOI: 10.1371/journal.pone.0040939] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Accepted: 06/15/2012] [Indexed: 12/04/2022] Open
Abstract
Background Males usually produce mating plugs to reduce sperm competition. However, females can conceivably also produce mating plugs in order to prevent unwanted, superfluous and energetically costly matings. In spiders–appropriate models for testing plugging biology hypotheses–mating plugs may consist of male genital parts and/or of amorphous covers consisting of glandular or sperm secretions. In the giant wood spider Nephila pilipes, a highly sexually dimorphic and polygamous species, males are known to produce ineffective embolic plugs through genital damage, but nothing is known about the origin and function of additional conspicuous amorphous plugs (AP) covering female genitals. Methodology We tested alternative hypotheses of the nature and function of AP in N. pilipes by staging mating trials with varying degrees of polyandry. No APs were ever formed during mating trials, which rules out the possibility of male AP formation. Instead, those females that oviposited produced the AP from a liquid secreted during egg sac formation. Polyandrous females were more likely to lay eggs and to produce the AP, as were those that mated longer and with more total insertions. Our further tests revealed that, in spite of being a side product of egg sac production, AP, when hardened, prevented any subsequent copulation. Conclusions We conclude that in the giant wood spider (Nephila pilipes), the amorphous mating plugs are not produced by the males, that repeated copulations (most likely polyandrous) are necessary for egg fertilization and AP formation, and that the AP represents a female adaptation to sexual conflict through prevention of unwanted, excessive copulations. Considering the largely unknown origin of amorphous plugs in spiders, we predict that a similar pattern might be detected in other clades, which would help elucidate the evolutionary interplay of various selection pressures responsible for the origin and maintenance of mating plugs.
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Affiliation(s)
- Matjaž Kuntner
- Institute of Biology, Scientific Research Centre, Slovenian Academy of Sciences and Arts, Ljubljana, Slovenia.
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30
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Herberstein M, Wignall A, Nessler S, Harmer A, Schneider J. How effective and persistent are fragmentsof male genitalia as mating plugs? Behav Ecol 2012. [DOI: 10.1093/beheco/ars088] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Allen LE, Barry KL, Holwell GI, Herberstein ME. Perceived risk of sperm competition affects juvenile development and ejaculate expenditure in male praying mantids. Anim Behav 2011. [DOI: 10.1016/j.anbehav.2011.09.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Neumann R, Schneider JM. Frequent Failure of Male Monopolization Strategies as a Cost of Female Choice in the Black Widow Spider Latrodectus tredecimguttatus. Ethology 2011. [DOI: 10.1111/j.1439-0310.2011.01971.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Stoltz JA, Andrade MCB. Female's courtship threshold allows intruding males to mate with reduced effort. Proc Biol Sci 2010; 277:585-92. [PMID: 19864292 PMCID: PMC2842684 DOI: 10.1098/rspb.2009.1554] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2009] [Accepted: 10/01/2009] [Indexed: 11/12/2022] Open
Abstract
Female decision rules can influence the nature and intensity of sexual selection on males, but empirical demonstrations of rules underlying choice are rare. We hypothesized that female choice is largely based on a courtship duration threshold in the Australian redback spider (Latrodectus hasselti) because females kill males before copulation is complete (premature cannibalism) and reduce their paternity if courtship is brief. We used published data to infer that the female's threshold is approximately 100 min of courtship. We support this hypothesis by showing that premature cannibalism is common when the male's courtship duration is below this threshold, but is infrequent and unrelated to duration once courtship exceeds the threshold. We then ask whether females discriminate the source of courtship when rival males compete, as this will determine the effect of the threshold on male competitive tactics. We staged competitions where 'resident' males initially courted females in the absence of competition, exceeding the courtship threshold before 'intruding' males were introduced. Intruding males mated rapidly but were not prematurely cannibalized by females, in contrast to cases where competition starts before the threshold is surpassed. This suggests females do not distinguish which male satisfies the threshold, allowing intruders to parasitize the courtship efforts of residents. To our knowledge, such exploitation of mating efforts by rival males mediated by a female choice threshold has not been demonstrated elsewhere. Ironically, this female choice threshold and the attendant possibility of courtship parasitism may lead to selection for lower-quality males to recognize and seek out (rather than avoid) webs in which competitors are already present.
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Affiliation(s)
- J A Stoltz
- Integrative Behaviour and Neuroscience Group, Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario M1C 1A4, Canada.
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Uhl G, Nessler SH, Schneider JM. Securing paternity in spiders? A review on occurrence and effects of mating plugs and male genital mutilation. Genetica 2009; 138:75-104. [PMID: 19705286 DOI: 10.1007/s10709-009-9388-5] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2009] [Accepted: 07/07/2009] [Indexed: 10/20/2022]
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Stoltz J, Elias D, Andrade M. Male courtship effort determines female response to competing rivals in redback spiders. Anim Behav 2009. [DOI: 10.1016/j.anbehav.2008.09.012] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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KASUMOVIC MM, ANDRADE MCB. A change in competitive context reverses sexual selection on male size. J Evol Biol 2008; 22:324-33. [DOI: 10.1111/j.1420-9101.2008.01648.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Sexual cannibalism facilitates genital damage in Argiope lobata (Araneae: Araneidae). Behav Ecol Sociobiol 2008. [DOI: 10.1007/s00265-008-0669-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Perampaladas K, Stoltz JA, Andrade MCB. Mated Redback Spider Females Re-Advertise Receptivity Months after Mating. Ethology 2008. [DOI: 10.1111/j.1439-0310.2008.01513.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Segoli M, Arieli R, Sierwald P, Harari AR, Lubin Y. Sexual Cannibalism in the Brown Widow Spider (Latrodectus geometricus). Ethology 2008. [DOI: 10.1111/j.1439-0310.2007.01462.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Stoltz JA, McNeil JN, Andrade MC. Males assess chemical signals to discriminate just-mated females from virgins in redback spiders. Anim Behav 2007. [DOI: 10.1016/j.anbehav.2007.03.011] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Nessler SH, Uhl G, Schneider JM. A non-sperm transferring genital trait under sexual selection: an experimental approach. Proc Biol Sci 2007; 274:2337-41. [PMID: 17644504 PMCID: PMC2288534 DOI: 10.1098/rspb.2007.0585] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Male genitalia are among the fastest evolving morphological characters, and at a general level sexual selection seems to be involved. But experimental determination of the functions of many remarkable genitalic elaborations is very rare. Here we present the first study to address experimentally the adaptive function of a male genital structure that is not involved in sperm transfer. Females of the orb-weaving spider Argiope bruennichi are sexually cannibalistic and polyandrous. The male increases his paternity by obstructing the female's insemination duct with a fragment of his complex genitalia (embolus tip). We manipulated males by detaching another species-specific structure, the median apophysis spur, and found that the spur promotes breakage of the embolus tip inside the female duct, but does not affect the probability and duration of copulation. These data are novel in that they suggest that a genitalic structure which does not transfer sperm nevertheless evolved in the context of sperm competition.
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Affiliation(s)
- Stefan H Nessler
- Department of Ethology, Biozentrum Grindel, University of Hamburg, Martin-Luther-King-Platz 3, 20146 Hamburg, Germany.
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Abstract
According to sexual cannibalism theory, male complicity in terminal mating can be adaptive when the male's future reproductive value is low relative to the benefits of self sacrifice. Spiders and insects that exhibit male sacrifice behavior (either complicity in cannibalism or spontaneous death associated with copulation) often also have male genitalia that stereotypically become broken or disfigured the first time they are used for copulation, potentially lowering his future reproductive value. Theoretical work on monogamy has identified male bias in the effective sex ratio as a precursor to the evolution of monogamy (including male sacrifice) as an adaptive form of paternity protection. Using phylogeny-based statistics and drawing on several phylogenetic studies of araneoid spiders, I investigate relationships between male sacrifice behavior, genital mutilation, extreme sexual size dimorphism, and the accumulation of multiple males in the female web (as an indicator of a male-based effective sex ratio). This investigation focuses on araneoid spiders because several independent origins of sacrifice behavior are known for this group and the phylogenetic structure of the lineage is relatively well studied. I report that male genital mutilation is significantly correlated with sacrifice behavior and argue that this finding is consistent with sexual cannibalism theory. Male sacrifice behavior is also correlated with male accumulation, a result that is consistent with theoretical work on the evolution of monogamy. Male accumulation and extreme sexual size dimorphism are correlated suggesting that sex-based differences in maturation time can lead to a male biased effective sex ratio. Similar patterns of correlated characters may hold for some insect taxa. Studying traits that have appeared independently in multiple lineages is a powerful method for developing general theories about the evolution of biological phenomena.
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Affiliation(s)
- Jeremy A Miller
- Department of Entomology, California Academy of Sciences, San Francisco, CA 94103, USA.
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Fromhage L, Schneider JM. Emasculation to plug up females: the significance of pedipalp damage in Nephila fenestrata. Behav Ecol 2006. [DOI: 10.1093/beheco/arj037] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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