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Lietzenmayer LB, Goldstein LM, Pasche JM, Taylor LA. Extreme natural size variation in both sexes of a sexually cannibalistic mantidfly. ROYAL SOCIETY OPEN SCIENCE 2022; 9:220544. [PMID: 35991330 PMCID: PMC9382211 DOI: 10.1098/rsos.220544] [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: 04/25/2022] [Accepted: 07/25/2022] [Indexed: 06/15/2023]
Abstract
In sexually cannibalistic animals, the relative sizes of potential mates often predict the outcome of aggressive encounters. Mantidflies are spider egg predators as larvae and generalist predators as adults. Unlike most cannibalistic species, there is considerable individual variation in body size in both sexes. Using preserved collections of Dicromantispa sayi, we focused on three body size metrics that we found to be positively correlated and accurately measured across researchers. We found extreme size variation in both sexes: the largest 10% of females were 1.72× larger than the smallest 10%, and the largest 10% of males were 1.65× larger than the smallest 10%. On average, females were 7.94% larger than males. In exploring possible causes of this variation, we uncovered differences among populations. To explore the effect of spider egg sac size on adult mantidfly size, we reared mantidfly larvae on egg sacs from two jumping spider species with small or large egg sacs. Mantidfly larvae reared on small egg sacs were smaller than those reared on large egg sacs. This study provides the groundwork to design ecologically relevant experiments exploring the causes and consequences of extreme size variation in an understudied system with intriguing natural history.
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Affiliation(s)
| | - Lauren M. Goldstein
- Entomology and Nematology Department, University of Florida, Gainesville, FL 32611, USA
- Department of Entomology, Michigan State University, East Lansing, MI 48824, USA
| | - Josephine M. Pasche
- Entomology and Nematology Department, University of Florida, Gainesville, FL 32611, USA
| | - Lisa A. Taylor
- Entomology and Nematology Department, University of Florida, Gainesville, FL 32611, USA
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Dharmarathne WDSC, Herberstein ME. Limitations of sperm transfer in the complex reproductive system of spiders. Biol J Linn Soc Lond 2022. [DOI: 10.1093/biolinnean/blab158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
In spiders, sperm transfer from the male to the female is indirect via secondary copulatory structures, the pedipalps. At the time of transfer the sperm are not mobile and the ejaculate needs to move through narrow male and female ducts to the female sperm storage organ. In addition, copulation duration can be very short, often limited to just a few seconds. Finally, sexual cannibalism and genital damage limits male life-time mating opportunities. These features of the reproductive biology in spiders are likely to result in sperm transfer constraints. Here we review the intrinsic and extrinsic sperm transfer limitations and conduct a meta-analysis on sperm transfer data from published data. Most of the information available relates to orb-web spiders, but our meta-analysis also includes non-orb-web spiders. Our review identifies some of the behavioural factors that have been shown to influence sperm transfer, and lists several morphological and physiological traits where we do not yet know how they might affect sperm transfer.
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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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Correa-Garhwal SM, Babb PL, Voight BF, Hayashi CY. Golden orb-weaving spider (Trichonephila clavipes) silk genes with sex-biased expression and atypical architectures. G3-GENES GENOMES GENETICS 2021; 11:6044138. [PMID: 33561241 PMCID: PMC8022711 DOI: 10.1093/g3journal/jkaa039] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 12/05/2020] [Indexed: 11/29/2022]
Abstract
Spider silks are renowned for their high-performance mechanical properties. Contributing to these properties are proteins encoded by the spidroin (spider fibroin) gene family. Spidroins have been discovered mostly through cDNA studies of females based on the presence of conserved terminal regions and a repetitive central region. Recently, genome sequencing of the golden orb-web weaver, Trichonephila clavipes, provided a complete picture of spidroin diversity. Here, we refine the annotation of T. clavipes spidroin genes including the reclassification of some as non-spidroins. We rename these non-spidroins as spidroin-like (SpL) genes because they have repetitive sequences and amino acid compositions like spidroins, but entirely lack the archetypal terminal domains of spidroins. Insight into the function of these spidroin and SpL genes was then examined through tissue- and sex-specific gene expression studies. Using qPCR, we show that some silk genes are upregulated in male silk glands compared to females, despite males producing less silk in general. We also find that an enigmatic spidroin that lacks a spidroin C-terminal domain is highly expressed in silk glands, suggesting that spidroins could assemble into fibers without a canonical terminal region. Further, we show that two SpL genes are expressed in silk glands, with one gene highly evolutionarily conserved across species, providing evidence that particular SpL genes are important to silk production. Together, these findings challenge long-standing paradigms regarding the evolutionary and functional significance of the proteins and conserved motifs essential for producing spider silks.
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Affiliation(s)
- Sandra M Correa-Garhwal
- Division of Invertebrate Zoology and Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, NY 10024, USA
| | - Paul L Babb
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.,Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Benjamin F Voight
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.,Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.,Institute for Translational Medicine and Therapeutics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Cheryl Y Hayashi
- Division of Invertebrate Zoology and Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, NY 10024, USA
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Quiñones-Lebrón SG, Kuntner M, Kralj-Fišer S. The effect of genetics, diet, and social environment on adult male size in a sexually dimorphic spider. Evol Ecol 2021. [DOI: 10.1007/s10682-020-10097-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Kuntner M, Coddington JA. Sexual Size Dimorphism: Evolution and Perils of Extreme Phenotypes in Spiders. ANNUAL REVIEW OF ENTOMOLOGY 2020; 65:57-80. [PMID: 31573828 DOI: 10.1146/annurev-ento-011019-025032] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Sexual size dimorphism is one of the most striking animal traits, and among terrestrial animals, it is most extreme in certain spider lineages. The most extreme sexual size dimorphism (eSSD) is female biased. eSSD itself is probably an epiphenomenon of gendered evolutionary drivers whose strengths and directions are diverse. We demonstrate that eSSD spider clades are aberrant by sampling randomly across all spiders to establish overall averages for female (6.9 mm) and male (5.6 mm) size. At least 16 spider eSSD clades exist. We explore why the literature does not converge on an overall explanation for eSSD and propose an equilibrium model featuring clade- and context-specific drivers of gender size variation. eSSD affects other traits such as sexual cannibalism, genital damage, emasculation, and monogyny with terminal investment. Coevolution with these extreme sexual phenotypes is termed eSSD mating syndrome. Finally, as costs of female gigantism increase with size, eSSD may represent an evolutionary dead end.
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Affiliation(s)
- Matjaž Kuntner
- Evolutionary Zoology Laboratory, Department of Organisms and Ecosystems Research, National Institute of Biology, SI-1000 Ljubljana, Slovenia;
- Department of Entomology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560-0105, USA;
- Evolutionary Zoology Laboratory, Institute of Biology ZRC SAZU, SI-1001 Ljubljana, Slovenia
| | - Jonathan A Coddington
- Department of Entomology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560-0105, USA;
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Kuntner M, Hamilton CA, Cheng RC, Gregorič M, Lupše N, Lokovšek T, Lemmon EM, Lemmon AR, Agnarsson I, Coddington JA, Bond JE. Golden Orbweavers Ignore Biological Rules: Phylogenomic and Comparative Analyses Unravel a Complex Evolution of Sexual Size Dimorphism. Syst Biol 2019; 68:555-572. [PMID: 30517732 PMCID: PMC6568015 DOI: 10.1093/sysbio/syy082] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 11/20/2018] [Accepted: 11/26/2018] [Indexed: 11/14/2022] Open
Abstract
Instances of sexual size dimorphism (SSD) provide the context for rigorous tests of biological rules of size evolution, such as Cope's rule (phyletic size increase), Rensch's rule (allometric patterns of male and female size), as well as male and female body size optima. In certain spider groups, such as the golden orbweavers (Nephilidae), extreme female-biased SSD (eSSD, female:male body length $\ge$2) is the norm. Nephilid genera construct webs of exaggerated proportions, which can be aerial, arboricolous, or intermediate (hybrid). First, we established the backbone phylogeny of Nephilidae using 367 anchored hybrid enrichment markers, then combined these data with classical markers for a reference species-level phylogeny. Second, we used the phylogeny to test Cope and Rensch's rules, sex specific size optima, and the coevolution of web size, type, and features with female and male body size and their ratio, SSD. Male, but not female, size increases significantly over time, and refutes Cope's rule. Allometric analyses reject the converse, Rensch's rule. Male and female body sizes are uncorrelated. Female size evolution is random, but males evolve toward an optimum size (3.2-4.9 mm). Overall, female body size correlates positively with absolute web size. However, intermediate sized females build the largest webs (of the hybrid type), giant female Nephila and Trichonephila build smaller webs (of the aerial type), and the smallest females build the smallest webs (of the arboricolous type). We propose taxonomic changes based on the criteria of clade age, monophyly and exclusivity, classification information content, and diagnosability. Spider families, as currently defined, tend to be between 37 million years old and 98 million years old, and Nephilidae is estimated at 133 Ma (97-146), thus deserving family status. We, therefore, resurrect the family Nephilidae Simon 1894 that contains Clitaetra Simon 1889, the Cretaceous GeratonephilaPoinar and Buckley (2012), Herennia Thorell 1877, IndoetraKuntner 2006, new rank, Nephila Leach 1815, Nephilengys L. Koch 1872, Nephilingis Kuntner 2013, Palaeonephila Wunderlich 2004 from Tertiary Baltic amber, and TrichonephilaDahl 1911, new rank. We propose the new clade Orbipurae to contain Araneidae Clerck 1757, Phonognathidae Simon 1894, new rank, and Nephilidae. Nephilid female gigantism is a phylogenetically ancient phenotype (over 100 Ma), as is eSSD, though their magnitudes vary by lineage.
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Affiliation(s)
- Matjaž Kuntner
- Evolutionary Zoology Laboratory, Department of Organisms and Ecosystems Research, National Institute of Biology, Večna pot 111, SI-1000 Ljubljana, Slovenia
- Evolutionary Zoology Laboratory, Biological Institute ZRC SAZU, Novi trg 2, SI-1001 Ljubljana, Slovenia
- Department of Entomology, National Museum of Natural History, Smithsonian Institution, 10th and Constitution, NW, Washington, DC 20560-0105, USA
- Centre for Behavioural Ecology and Evolution, College of Life Sciences, Hubei University, 368 Youyi Road, Wuhan, Hubei 430062, China
| | - Chris A Hamilton
- Department of Entomology, Plant Pathology, & Nematology, University of Idaho, 875 Perimeter Dr. MS 2329, Moscow, ID 83844-2329, USA
| | - Ren-Chung Cheng
- Evolutionary Zoology Laboratory, Biological Institute ZRC SAZU, Novi trg 2, SI-1001 Ljubljana, Slovenia
- Department of Life Sciences, National Chung Hsing University, No.145 Xingda Rd., South Dist., Taichung City 402, Taiwan
| | - Matjaž Gregorič
- Evolutionary Zoology Laboratory, Biological Institute ZRC SAZU, Novi trg 2, SI-1001 Ljubljana, Slovenia
| | - Nik Lupše
- Evolutionary Zoology Laboratory, Biological Institute ZRC SAZU, Novi trg 2, SI-1001 Ljubljana, Slovenia
- Division of Animal Evolutionary Biology, Department of Zoology, Faculty of Science, Charles University, Viničná 7, 128 44 Prague, Czech Republic
| | - Tjaša Lokovšek
- Evolutionary Zoology Laboratory, Biological Institute ZRC SAZU, Novi trg 2, SI-1001 Ljubljana, Slovenia
| | - Emily Moriarty Lemmon
- Department of Biological Science, Florida State University, 319 Stadium Dr., Tallahassee, FL 32306-4295, USA
| | - Alan R Lemmon
- Department of Scientific Computing, Florida State University, 400 Dirac Science Library, Tallahassee, FL 32306-4120, USA
| | - Ingi Agnarsson
- Department of Entomology, National Museum of Natural History, Smithsonian Institution, 10th and Constitution, NW, Washington, DC 20560-0105, USA
- Department of Biology, University of Vermont, 316 Marsh Life Science Building, 109 Carrigan Drive, Burlington, VT 05405-0086, USA
| | - Jonathan A Coddington
- Department of Entomology, National Museum of Natural History, Smithsonian Institution, 10th and Constitution, NW, Washington, DC 20560-0105, USA
| | - Jason E Bond
- Department of Entomology and Nematology, University of California Davis, 1 Shields Drive, Davis, CA 95616, USA
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Reichert MS, Ronacher B. Temporal integration of conflicting directional cues in sound localization. J Exp Biol 2019; 222:jeb.208751. [DOI: 10.1242/jeb.208751] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 11/12/2019] [Indexed: 01/13/2023]
Abstract
Sound localization is fundamental to hearing. In nature, sound degradation and noise erode directional cues and can generate conflicting directional perceptions across different subcomponents of sounds. Little is known about how sound localization is achieved in the face of conflicting directional cues in non-human animals, although this is relevant for many species in which sound localization in noisy conditions mediates mate finding or predator avoidance. We studied the effects of conflicting directional cues in male grasshoppers, Chorthippus biguttulus, which orient towards signaling females. We presented playbacks varying in the number and temporal position of song syllables providing directional cues in the form of either time or amplitude differences between two speakers. Males oriented towards the speaker broadcasting a greater number of leading or louder syllables. For a given number of syllables providing directional information, syllables with timing differences at the song's beginning were weighted most heavily, while syllables with intensity differences were weighted most heavily when they were in the middle of the song. When timing and intensity cues conflicted, the magnitude and temporal position of each cue determined their relative influence on lateralization, and males sometimes quickly corrected their directional responses. We discuss our findings with respect to similar results from humans.
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Affiliation(s)
- Michael S. Reichert
- Department of Integrative Biology, Oklahoma State University, 501 Life Sciences West, Stillwater, OK, 74078 USA
- Institut für Biologie, Abteilung Verhaltensphysiologie, Humboldt-Universität zu Berlin, Philippstraße 13, Haus 18, 10099 Berlin, Germany
| | - Bernhard Ronacher
- Institut für Biologie, Abteilung Verhaltensphysiologie, Humboldt-Universität zu Berlin, Philippstraße 13, Haus 18, 10099 Berlin, Germany
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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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Cory AL, Schneider JM. Mate availability does not influence mating strategies in males of the sexually cannibalistic spider Argiope bruennichi. PeerJ 2018; 6:e5360. [PMID: 30123703 PMCID: PMC6086085 DOI: 10.7717/peerj.5360] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 07/12/2018] [Indexed: 11/20/2022] Open
Abstract
Background Sexual selection theory predicts that male investment in a current female should be a function of female density and male competition. While many studies have focused on male competition, the impact of female density on male mating investment has been widely neglected. Here, we aimed to close this gap and tested effects of mate density on male mating decisions in the orb-web spider Argiope bruennichi. Males of this species mutilate their genitalia during copulation, which reduces sperm competition and limits their mating rate to a maximum of two females (bigyny). The mating rate is frequently further reduced by female aggression and cannibalization. Males can reduce the risk of cannibalism if they jump off the female in time, but will then transfer fewer sperm. An alternative solution of this trade-off is to copulate longer, commit self-sacrifice and secure higher minimal paternity. The self-sacrificial strategy may be adaptive if prospective mating chances are uncertain. In A. bruennichi, this uncertainty may arise from quick changes in population dynamics. Therefore, we expected that males would immediately respond to information about low or high mate availability and opt for self-sacrifice after a single copulation under low mate availability. If male survival depends on information about prospective mating chances, we further predicted that under high mate availability, we would find a higher rate of males that leave the first mating partner to follow a bigynous mating strategy. Method We used naïve males and compared their mating decisions among two treatments that differed in the number of signalling females. In the high mate availability treatment, males perceived pheromone signals from four adult, virgin females, while in the low mate availability treatment only one of four females was adult and virgin and the other three were penultimate and unreceptive. Results Males took more time to start mate searching if mate availability was low. However, a self-sacrificial strategy was not more likely under low mate availability. We found no effects of treatment on the duration of copulation, the probability to survive the first copulation or the probability of bigyny. Interestingly, survival chances depended on male size and were higher in small males. Discussion Our results do not support the hypothesis that mate density variation affects male mating investment, although they clearly perceived mate density, which they presumably assessed by pheromone quantity. One reason for the absence of male adjustments to mating tactics could be that adaptations to survive female attacks veil adaptations that facilitate mating decisions.
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Affiliation(s)
- Anna-Lena Cory
- Institute of Zoology, Universität Hamburg, Hamburg, 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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Turk E, Kuntner M, Kralj-Fišer S. Cross-sex genetic correlation does not extend to sexual size dimorphism in spiders. Naturwissenschaften 2017; 105:1. [DOI: 10.1007/s00114-017-1529-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 11/23/2017] [Accepted: 11/27/2017] [Indexed: 12/22/2022]
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Toft S, Albo MJ. The shield effect: nuptial gifts protect males against pre-copulatory sexual cannibalism. Biol Lett 2017; 12:rsbl.2015.1082. [PMID: 27194284 DOI: 10.1098/rsbl.2015.1082] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 04/20/2016] [Indexed: 11/12/2022] Open
Abstract
Several not mutually exclusive functions have been ascribed to nuptial gifts across different taxa. Although the idea that a nuptial prey gift may protect the male from pre-copulatory sexual cannibalism is attractive, it has previously been considered of no importance based on indirect evidence and rejected by experimental tests. We reinvestigated whether nuptial gifts may function as a shield against female attacks during mating encounters in the spider Pisaura mirabilis and whether female hunger influences the likelihood of cannibalistic attacks. The results showed that pre-copulatory sexual cannibalism was enhanced when males courted without a gift and this was independent of female hunger. We propose that the nuptial gift trait has evolved partly as a counteradaptation to female aggression in this spider species.
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Affiliation(s)
- Søren Toft
- Department of Bioscience, Aarhus University, Aarhus 8000, Denmark
| | - Maria J Albo
- Department of Bioscience, Aarhus University, Aarhus 8000, Denmark Laboratorio de Etología, Ecología y Evolución, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
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Neumann R, Ruppel N, Schneider JM. Fitness implications of sex-specific catch-up growth in Nephila senegalensis, a spider with extreme reversed SSD. PeerJ 2017; 5:e4050. [PMID: 29158981 PMCID: PMC5694211 DOI: 10.7717/peerj.4050] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 10/26/2017] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND Animal growth is often constrained by unfavourable conditions and divergences from optimal body size can be detrimental to an individual's fitness, particularly in species with determinate growth and a narrow time-frame for life-time reproduction. Growth restriction in early juvenile stages can later be compensated by means of plastic developmental responses, such as adaptive catch-up growth (the compensation of growth deficits through delayed development). Although sex differences regarding the mode and degree of growth compensation have been coherently predicted from sex-specific fitness payoffs, inconsistent results imply a need for further research. We used the African Nephila senegalensis, representing an extreme case of female-biased sexual size dimorphism (SSD), to study fitness implications of sex-specific growth compensation. We predicted effective catch-up growth in early food-restricted females to result in full compensation of growth deficits and a life-time fecundity (LTF) equivalent to unrestricted females. Based on a stronger trade-off between size-related benefits and costs of a delayed maturation, we expected less effective catch-up growth in males. METHODS We tracked the development of over one thousand spiders in different feeding treatments, e.g., comprising a fixed period of early low feeding conditions followed by unrestricted feeding conditions, permanent unrestricted feeding conditions, or permanent low feeding conditions as a control. In a second experimental section, we assessed female fitness by measuring LTF in a subset of females. In addition, we tested whether compensatory development affected the reproductive lifespan in both sexes and analysed genotype-by-treatment interactions as a potential cause of variation in life-history traits. RESULTS Both sexes delayed maturation to counteract early growth restriction, but only females achieved full compensation of adult body size. Female catch-up growth resulted in equivalent LTF compared to unrestricted females. We found significant interactions between experimental treatments and sex as well as between treatments and family lineage, suggesting that family-specific responses contribute to the unusually large variation of life-history traits in Nephila spiders. Our feeding treatments had no effect on the reproductive lifespan in either sex. DISCUSSION Our findings are in line with predictions of life-history theory and corroborate strong fecundity selection to result in full female growth compensation. Males showed incomplete growth compensation despite a delayed development, indicating relaxed selection on large size and a stronger trade-off between late maturation and size-related benefits. We suggest that moderate catch-up growth in males is still adaptive as a 'bet-hedging' strategy to disperse unavoidable costs between life-history traits affected by early growth restriction (the duration of development and adult size).
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Affiliation(s)
- Rainer Neumann
- Zoologisches Institut, Biozentrum Grindel, Universität Hamburg, Hamburg, Germany
| | - Nicole Ruppel
- Zoologisches Institut, Biozentrum Grindel, Universität Hamburg, Hamburg, Germany
| | - Jutta M. Schneider
- Zoologisches Institut, Biozentrum Grindel, Universität Hamburg, Hamburg, Germany
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Chelini MC, Hebets E. Field evidence challenges the often-presumed relationship between early male maturation and female-biased sexual size dimorphism. Ecol Evol 2017; 7:9592-9601. [PMID: 29187992 PMCID: PMC5696407 DOI: 10.1002/ece3.3450] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 08/14/2017] [Accepted: 08/15/2017] [Indexed: 11/25/2022] Open
Abstract
Female‐biased sexual size dimorphism (SSD) is often considered an epiphenomenon of selection for the increased mating opportunities provided by early male maturation (i.e., protandry). Empirical evidence of the adaptive significance of protandry remains nonetheless fairly scarce. We use field data collected throughout the reproductive season of an SSD crab spider, Mecaphesa celer, to test two hypotheses: Protandry provides fitness benefits to males, leading to female‐biased SSD, or protandry is an indirect consequence of selection for small male size/large female size. Using field‐collected data, we modeled the probability of mating success for females and males according to their timing of maturation. We found that males matured earlier than females and the proportion of virgin females decreased abruptly early in the season, but unexpectedly increased afterward. Timing of female maturation was not related to clutch size, but large females tended to have more offspring than small females. Timing of female and male maturation was inversely related to size at adulthood, as early‐maturing individuals were larger than late‐maturing ones, suggesting that both sexes exhibit some plasticity in their developmental trajectories. Such plasticity indicates that protandry could co‐occur with any degree and direction of SSD. Our calculation of the probability of mating success along the season shows multiple male maturation time points with similar predicted mating success. This suggests that males follow multiple strategies with equal success, trading‐off access to virgin females with intensity of male–male competition. Our results challenge classic hypotheses linking protandry and female‐biased SSD, and emphasize the importance of directly testing the often‐assumed relationships between co‐occurring animal traits.
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Affiliation(s)
| | - Eileen Hebets
- School of Biological Sciences University of Nebraska - Lincoln Lincoln NE USA
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17
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Jayaweera A, Barry KL. Male antenna morphology and its effect on scramble competition in false garden mantids. Naturwissenschaften 2017; 104:75. [PMID: 28836048 DOI: 10.1007/s00114-017-1494-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 07/26/2017] [Accepted: 07/27/2017] [Indexed: 11/29/2022]
Abstract
Well-developed antennae are crucial for many insects, but especially for scramble competitors, who race to find their mates using female sex cues. In these systems, the ability of males to locate females quickly is thought to be under strong selection. A rarely tested assumption is that males with more sensory structures are able to locate females faster. In the present study, we used the false garden mantid Pseudomantis albofimbriata to investigate male antennal morphology and its effect on male efficiency in finding a mate. We used scanning electron microscopy to describe the major sensilla types and their arrangement along the length of male antennae. We also conducted field enclosure trials relating male antennal morphology to scramble competition in this system. We identified six different types of antennal sensilla (cheatic, trichoid, basiconic, grooved peg, ceolocapitular and campaniform) on male P. albofimbriata antennae. As expected, males who had more trichoid sensilla located females quicker than did males with fewer sensilla. Results of the current study suggest that antenna morphology plays a significant role in mate location and hence scramble competition in the P. albofimbriata mating system.
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Affiliation(s)
- Anuradhi Jayaweera
- Department of Biological Sciences, Faculty of Science and Engineering, Macquarie University, North Ryde, NSW, 2109, Australia.
| | - Katherine L Barry
- Department of Biological Sciences, Faculty of Science and Engineering, Macquarie University, North Ryde, NSW, 2109, Australia
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18
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Cheng RC, Zhang S, Chen YC, Lee CY, Chou YL, Ye HY, Piorkowski D, Liao CP, Tso IM. Nutrient intake determines post-maturity molting in the golden orb-web spider Nephila pilipes (Araneae: Araneidae). ACTA ACUST UNITED AC 2017; 220:2260-2264. [PMID: 28396355 DOI: 10.1242/jeb.153569] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 04/05/2017] [Indexed: 11/20/2022]
Abstract
While molting occurs in the development of many animals, especially arthropods, post-maturity molting (PMM, organisms continue to molt after sexual maturity) has received little attention. The mechanism of molting has been studied intensively; however, the mechanism of PMM remains unknown although it is suggested to be crucial for the development of body size. In this study, we investigated factors that potentially induce PMM in the golden orb-web spider Nephila pilipes, which has the greatest degree of sexual dimorphism among terrestrial animals. We manipulated the mating history and the nutrient consumption of the females to examine whether they affect PMM. The results showed that female spiders under low nutrition were more likely to molt as adults, and mating had no significant influence on the occurrence of PMM. Moreover, spiders that underwent PMM lived longer than those that did not and their body sizes were significantly increased. Therefore, we concluded that nutritional condition rather than mating history affect PMM.
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Affiliation(s)
- Ren-Chung Cheng
- Department of Life Science, Tunghai University, Taichung 40704, Taiwan.,Institute of Biology, Scientific Research Centre, Slovenian Academy of Sciences and Arts, Novi trg 2, 1000, Ljubljana, Slovenia
| | - Shichang Zhang
- Department of Life Science, Tunghai University, Taichung 40704, Taiwan
| | - Yu-Chun Chen
- Department of Life Science, Tunghai University, Taichung 40704, Taiwan
| | - Chia-Yi Lee
- Department of Life Science, Tunghai University, Taichung 40704, Taiwan
| | - Yi-Ling Chou
- Department of Life Science, Tunghai University, Taichung 40704, Taiwan
| | - Hui-Ying Ye
- Department of Life Science, Tunghai University, Taichung 40704, Taiwan
| | - Dakota Piorkowski
- Department of Life Science, Tunghai University, Taichung 40704, Taiwan
| | - Chen-Pan Liao
- Department of Life Science, Tunghai University, Taichung 40704, Taiwan
| | - I-Min Tso
- Department of Life Science, Tunghai University, Taichung 40704, Taiwan .,Center for Tropical Ecology and Biodiversity, Tunghai University, Taichung 40704, Taiwan
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19
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Herberstein ME, Painting CJ, Holwell GI. Scramble Competition Polygyny in Terrestrial Arthropods. ADVANCES IN THE STUDY OF BEHAVIOR 2017. [DOI: 10.1016/bs.asb.2017.01.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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20
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Kuntner M, Cheng RC, Kralj-Fišer S, Liao CP, Schneider JM, Elgar MA. The evolution of genital complexity and mating rates in sexually size dimorphic spiders. BMC Evol Biol 2016; 16:242. [PMID: 27829358 PMCID: PMC5103378 DOI: 10.1186/s12862-016-0821-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 10/28/2016] [Indexed: 11/10/2022] Open
Abstract
Background Genital diversity may arise through sexual conflict over polyandry, where male genital features function to manipulate female mating frequency against her interest. Correlated genital evolution across animal groups is consistent with this view, but a link between genital complexity and mating rates remains to be established. In sexually size dimorphic spiders, golden orbweaving spiders (Nephilidae) males mutilate their genitals to form genital plugs, but these plugs do not always prevent female polyandry. In a comparative framework, we test whether male and female genital complexity coevolve, and how these morphologies, as well as sexual cannibalism, relate to the evolution of mating systems. Results Using a combination of comparative tests, we show that male genital complexity negatively correlates with female mating rates, and that levels of sexual cannibalism negatively correlate with male mating rates. We also confirm a positive correlation between male and female genital complexity. The macroevolutionary trajectory is consistent with a repeated evolution from polyandry to monandry coinciding with the evolution towards more complex male genitals. Conclusions These results are consistent with the predictions from sexual conflict theory, although sexual conflict may not be the only mechanism responsible for the evolution of genital complexity and mating systems. Nevertheless, our comparative evidence suggests that in golden orbweavers, male genital complexity limits female mating rates, and sexual cannibalism by females coincides with monogyny. Electronic supplementary material The online version of this article (doi:10.1186/s12862-016-0821-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Matjaž Kuntner
- Institute of Biology, Research Centre of the Slovenian Academy of Sciences and Arts, Ljubljana, Slovenia. .,National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
| | - Ren-Chung Cheng
- Institute of Biology, Research Centre of the Slovenian Academy of Sciences and Arts, Ljubljana, Slovenia
| | - Simona Kralj-Fišer
- Institute of Biology, Research Centre of the Slovenian Academy of Sciences and Arts, Ljubljana, Slovenia
| | - Chen-Pan Liao
- Department of Life Science, Tunghai University, Taichung, Taiwan
| | - Jutta M Schneider
- Zoological Institute, Biozentrum Grindel, University of Hamburg, Hamburg, Germany
| | - Mark A Elgar
- School of BioSciences, University of Melbourne, Victoria, 3010, Australia
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21
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Chelini MC, Hebets EA. Polyandry in the absence of fitness benefits in a species with female-biased sexual size dimorphism. Anim Behav 2016. [DOI: 10.1016/j.anbehav.2016.07.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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22
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Lupše N, Cheng RC, Kuntner M. Coevolution of female and male genital components to avoid genital size mismatches in sexually dimorphic spiders. BMC Evol Biol 2016; 16:161. [PMID: 27535025 PMCID: PMC4989301 DOI: 10.1186/s12862-016-0734-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 08/05/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In most animal groups, it is unclear how body size variation relates to genital size differences between the sexes. While most morphological features tend to scale with total somatic size, this does not necessarily hold for genitalia because divergent evolution in somatic size between the sexes would cause genital size mismatches. Theory predicts that the interplay of female-biased sexual size dimorphism (SSD) and sexual genital size dimorphism (SGD) should adhere to the 'positive genital divergence', the 'constant genital divergence', or the 'negative genital divergence' model, but these models remain largely untested. We test their validity in the spider family Nephilidae known for the highest degrees of SSD among terrestrial animals. RESULTS Through comparative analyses of sex-specific somatic and genital sizes, we first demonstrate that 99 of the 351 pairs of traits are phylogenetically correlated. Through factor analyses we then group these traits for MCMCglmm analyses that test broader correlation patterns, and these reveal significant correlations in 10 out of the 36 pairwise comparisons. Both types of analyses agree that female somatic and internal genital sizes evolve independently. While sizes of non-intromittent male genital parts coevolve with male body size, the size of the intromittent male genital parts is independent of the male somatic size. Instead, male intromittent genital size coevolves with female (external and, in part, internal) genital size. All analyses also agree that SGD and SSD evolve independently. CONCLUSIONS Internal dimensions of female genitalia evolve independently of female body size in nephilid spiders, and similarly, male intromittent genital size evolves independently of the male body size. The size of the male intromittent organ (the embolus) and the sizes of female internal and external genital components thus seem to respond to selection against genital size mismatches. In accord with these interpretations, we reject the validity of the existing theoretical models of genital and somatic size dimorphism in spiders.
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Affiliation(s)
- Nik Lupše
- Institute of Biology, Research Centre of the Slovenian Academy of Sciences and Arts, Ljubljana, Slovenia
| | - Ren-Chung Cheng
- Institute of Biology, Research Centre of the Slovenian Academy of Sciences and Arts, Ljubljana, Slovenia
| | - Matjaž Kuntner
- Institute of Biology, Research Centre of the Slovenian Academy of Sciences and Arts, Ljubljana, Slovenia. .,Department of Entomology, National Museum of Natural History, Smithsonian Institution, Washington, DC, 20013-7012, USA.
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23
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Evolutionary Pathways Maintaining Extreme Female-Biased Sexual Size Dimorphism: Convergent Spider Cases Defy Common Patterns. Evol Biol 2016. [DOI: 10.1007/978-3-319-41324-2_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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24
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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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25
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Cheng RC, Kuntner M. Phylogeny suggests nondirectional and isometric evolution of sexual size dimorphism in argiopine spiders. Evolution 2014; 68:2861-72. [PMID: 25130435 DOI: 10.1111/evo.12504] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 06/15/2014] [Indexed: 11/28/2022]
Abstract
Sexual dimorphism describes substantial differences between male and female phenotypes. In spiders, sexual dimorphism research almost exclusively focuses on size, and recent studies have recovered steady evolutionary size increases in females, and independent evolutionary size changes in males. Their discordance is due to negative allometric size patterns caused by different selection pressures on male and female sizes (converse Rensch's rule). Here, we investigated macroevolutionary patterns of sexual size dimorphism (SSD) in Argiopinae, a global lineage of orb-weaving spiders with varying degrees of SSD. We devised a Bayesian and maximum-likelihood molecular species-level phylogeny, and then used it to reconstruct sex-specific size evolution, to examine general hypotheses and different models of size evolution, to test for sexual size coevolution, and to examine allometric patterns of SSD. Our results, revealing ancestral moderate sizes and SSD, failed to reject the Brownian motion model, which suggests a nondirectional size evolution. Contrary to predictions, male and female sizes were phylogenetically correlated, and SSD evolution was isometric. We interpret these results to question the classical explanations of female-biased SSD via fecundity, gravity, and differential mortality. In argiopines, SSD evolution may be driven by these or additional selection mechanisms, but perhaps at different phylogenetic scales.
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Affiliation(s)
- Ren-Chung Cheng
- Institute of Biology, Scientific Research Centre of the Slovenian Academy of Sciences and Arts, Ljubljana, Slovenia.
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26
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Kuntner M, Elgar MA. Evolution and maintenance of sexual size dimorphism: aligning phylogenetic and experimental evidence. Front Ecol Evol 2014. [DOI: 10.3389/fevo.2014.00026] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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