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Greenwood JF, Granados GL, Secor SM, Todd BD, Showalter I, Hedrick BP, Brennan PLR. Divergent Genital Morphologies and Female-Male Covariation in Watersnakes. Integr Comp Biol 2022; 62:icac020. [PMID: 35512541 DOI: 10.1093/icb/icac020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Genital evolution can be driven by diverse selective pressures. Across taxa we see evidence of covariation between males and females, as well as divergent genital morphologies between closely related species. Quantitative analyses of morphological changes in coevolving male and female genitalia have not yet been shown in vertebrates. This study uses 2D and 3D geometric morphometrics to quantitatively compare the complex shapes of vaginal pouches and hemipenes across three species of watersnakes (the sister taxa Nerodia fasciata, N. sipedon, and a close relative N. rhombifer) to address the relationship between genital morphology and divergence time in a system where sexual conflict may have driven sexually antagonistic coevolution of genital traits. Our pairwise comparisons of shape differences across species show that the sister species have male and female genitalia that are significantly different from each other, but more similar to each other than to N. rhombifer. We also determine that the main axes of shape variation are the same for males and females, with changes that relate to deeper bilobation of the vaginal pouch and hemipenes. In males, the protrusion of the region of spines at the base of the hemipene trades off with the degree of bilobation, suggesting amelioration of sexual conflict, perhaps driven by changes in the relative size of the entrance of the vaginal pouch that could have made spines less effective.
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Affiliation(s)
- J F Greenwood
- Department of Biological Sciences, Mount Holyoke College, South Hadley, MA 01075
| | - G Lara Granados
- Department of Biological Sciences, Mount Holyoke College, South Hadley, MA 01075
| | - S M Secor
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL 35487
| | - B D Todd
- Department of Wildlife, Fish, and Conservation Biology, University of California, Davis, Davis, CA 95616
| | - I Showalter
- Biology Department, University of Massachusetts-Amherst, Amherst, MA 01003
| | - B P Hedrick
- Department of Cell Biology and Anatomy, Louisiana State University Health Sciences Center, New Orleans LA 70012
| | - P L R Brennan
- Department of Biological Sciences, Mount Holyoke College, South Hadley, MA 01075
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Glaudas X, Rice SE, Clark RW, Alexander GJ. The intensity of sexual selection, body size and reproductive success in a mating system with male–male combat: is bigger better? OIKOS 2020. [DOI: 10.1111/oik.07223] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Xavier Glaudas
- School of Animal, Plant and Environmental Sciences, Univ. of the Witwatersrand Johannesburg PO Wits 2050 South Africa
| | - Stephen E. Rice
- Dept of Biology, San Diego State Univ. San Diego CA USA
- Dept of Natural Sciences, Fairmont State Univ. Fairmont WV USA
| | | | - Graham J. Alexander
- School of Animal, Plant and Environmental Sciences, Univ. of the Witwatersrand Johannesburg PO Wits 2050 South Africa
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Levine BA, Douglas MR, Yackel Adams AA, Lardner B, Reed RN, Savidge JA, Douglas ME. Genomic pedigree reconstruction identifies predictors of mating and reproductive success in an invasive vertebrate. Ecol Evol 2019; 9:11863-11877. [PMID: 31695893 PMCID: PMC6822066 DOI: 10.1002/ece3.5694] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 09/02/2019] [Indexed: 01/16/2023] Open
Abstract
The persistence of an invasive species is influenced by its reproductive ecology, and a successful control program must operate on this premise. However, the reproductive ecology of invasive species may be enigmatic due to factors that also limit their management, such as cryptic coloration and behavior. We explored the mating and reproductive ecology of the invasive Brown Treesnake (BTS: Boiga irregularis) by reconstructing a multigenerational genomic pedigree based on 654 single nucleotide polymorphisms for a geographically closed population established in 2004 on Guam (N = 426). The pedigree allowed annual estimates of individual mating and reproductive success to be inferred for snakes in the study population over a 14-year period. We then employed generalized linear mixed models to gauge how well phenotypic and genomic data could predict sex-specific annual mating and reproductive success. Average snout-vent length (SVL), average body condition index (BCI), and trappability were significantly related to annual mating success for males, with average SVL also related to annual mating success for females. Male and female annual reproductive success was positively affected by SVL, BCI, and trappability. Surprisingly, the degree to which individuals were inbred had no effect on annual mating or reproductive success. When juxtaposed with current control methods, these results indicate that baited traps, a common interdiction tool, may target fecund BTS in some regards but not others. Our study emphasizes the importance of reproductive ecology as a focus for improving BTS control and promotes genomic pedigree reconstruction for such an endeavor in this invasive species and others.
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Affiliation(s)
- Brenna A. Levine
- University of ArkansasFayettevilleArkansas
- Present address:
University of TulsaTulsaOklahoma
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Janicke T, Häderer IK, Lajeunesse MJ, Anthes N. Darwinian sex roles confirmed across the animal kingdom. SCIENCE ADVANCES 2016; 2:e1500983. [PMID: 26933680 PMCID: PMC4758741 DOI: 10.1126/sciadv.1500983] [Citation(s) in RCA: 225] [Impact Index Per Article: 28.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 11/30/2015] [Indexed: 06/01/2023]
Abstract
Since Darwin's conception of sexual selection theory, scientists have struggled to identify the evolutionary forces underlying the pervasive differences between male and female behavior, morphology, and physiology. The Darwin-Bateman paradigm predicts that anisogamy imposes stronger sexual selection on males, which, in turn, drives the evolution of conventional sex roles in terms of female-biased parental care and male-biased sexual dimorphism. Although this paradigm forms the cornerstone of modern sexual selection theory, it still remains untested across the animal tree of life. This lack of evidence has promoted the rise of alternative hypotheses arguing that sex differences are entirely driven by environmental factors or chance. We demonstrate that, across the animal kingdom, sexual selection, as captured by standard Bateman metrics, is indeed stronger in males than in females and that it is evolutionarily tied to sex biases in parental care and sexual dimorphism. Our findings provide the first comprehensive evidence that Darwin's concept of conventional sex roles is accurate and refute recent criticism of sexual selection theory.
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Affiliation(s)
- Tim Janicke
- Centre d’Écologie Fonctionnelle et Évolutive, UMR 5175, CNRS, Université de Montpellier, Université Paul-Valéry Montpellier, École Pratique des Hautes Études, 1919 Route de Mende, 34293 Montpellier Cedex 05, France
| | - Ines K. Häderer
- Animal Evolutionary Ecology Group, Institute for Evolution and Ecology, University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany
| | - Marc J. Lajeunesse
- Department of Integrative Biology, University of South Florida, Tampa, FL 33620, USA
| | - Nils Anthes
- Animal Evolutionary Ecology Group, Institute for Evolution and Ecology, University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany
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Levine BA, Smith CF, Schuett GW, Douglas MR, Davis MA, Douglas ME. Bateman-Trivers in the 21st Century: sexual selection in a North American pitviper. Biol J Linn Soc Lond 2014. [DOI: 10.1111/bij.12434] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Brenna A. Levine
- Department of Biological Sciences; University of Arkansas; Fayetteville AR 72701 USA
| | - Charles F. Smith
- Department of Biology; Wofford College; Spartanburg SC 29303 USA
- The Copperhead Institute; PO Box 6755 Spartanburg SC 29304 USA
- Chiricahua Desert Museum; PO Box 376 Rodeo NM 88056 USA
| | - Gordon W. Schuett
- The Copperhead Institute; PO Box 6755 Spartanburg SC 29304 USA
- Chiricahua Desert Museum; PO Box 376 Rodeo NM 88056 USA
- Department of Biology and Center for Behavioral Neuroscience; Georgia State University; Atlanta GA 30303 USA
| | - Marlis R. Douglas
- Department of Biological Sciences; University of Arkansas; Fayetteville AR 72701 USA
- Illinois Natural History Survey; Prairie Research Institute; University of Illinois; Champaign IL 61820 USA
| | - Mark A. Davis
- Illinois Natural History Survey; Prairie Research Institute; University of Illinois; Champaign IL 61820 USA
| | - Michael E. Douglas
- Department of Biological Sciences; University of Arkansas; Fayetteville AR 72701 USA
- Illinois Natural History Survey; Prairie Research Institute; University of Illinois; Champaign IL 61820 USA
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Friesen CR, Kerns AR, Mason RT. Factors influencing paternity in multiply mated female red-sided garter snakes and the persistent use of sperm stored over winter. Behav Ecol Sociobiol 2014. [DOI: 10.1007/s00265-014-1749-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Friesen CR, Mason RT, Arnold SJ, Estes S. Patterns of sperm use in two populations of Red-sided Garter Snake (Thamnophis sirtalis parietalis) with long-term female sperm storage. CAN J ZOOL 2014. [DOI: 10.1139/cjz-2013-0195] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Long-term sperm storage may contribute to postcopulatory sexual selection because it enhances the commingling of sperm from different males within the female reproductive tract, which is the prerequisite for sperm competition. Long-term sperm storage and multiple paternity has been documented in snakes, but the identity of the last potential father is usually unknown in studies demonstrating multiple paternity. Here we present the first study in Red-sided Garter Snakes (Thamnophis sirtalis parietalis (Say in James, 1832)) to use experimental population crosses to assess stored sperm usage, mate-order effects, and the potential for interpopulational gametic isolation. We found a high rate of multiple paternity indicative of ubiquitous long-term sperm storage in this system, and observed last-male sperm precedence in all families (n = 66). Postzygotic isolation was absent, and we observed only a weak asymmetry in pattern of sperm precedence in our population crosses.
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Affiliation(s)
- Christopher R. Friesen
- Department of Zoology, Oregon State University, Cordley Hall 3029, Corvallis, OR 97330, USA
- School of Biological Sciences, University of Sydney, Heydon-Laurence Building AO8, Science Road, NSW 2006, Australia
| | - Robert T. Mason
- Department of Zoology, Oregon State University, Cordley Hall 3029, Corvallis, OR 97330, USA
| | - Stevan J. Arnold
- Department of Zoology, Oregon State University, Cordley Hall 3029, Corvallis, OR 97330, USA
| | - Suzanne Estes
- Department of Biology, Portland State University, 1719 SW 10th Avenue, SRTC Room 246, Portland, OR 97201, USA
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Shuster SM, Briggs WR, Dennis PA. How multiple mating by females affects sexual selection. Philos Trans R Soc Lond B Biol Sci 2013; 368:20120046. [PMID: 23339237 DOI: 10.1098/rstb.2012.0046] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Multiple mating by females is widely thought to encourage post-mating sexual selection and enhance female fitness. We show that whether polyandrous mating has these effects depends on two conditions. Condition 1 is the pattern of sperm utilization by females; specifically, whether, among females, male mating number, m (i.e. the number of times a male mates with one or more females) covaries with male offspring number, o. Polyandrous mating enhances sexual selection only when males who are successful at multiple mating also sire most or all of each of their mates' offspring, i.e. only when Cov(♂)(m,o), is positive. Condition 2 is the pattern of female reproductive life-history; specifically, whether female mating number, m, covaries with female offspring number, o. Only semelparity does not erode sexual selection, whereas iteroparity (i.e. when Cov(♀)(m,o), is positive) always increases the variance in offspring numbers among females, which always decreases the intensity of sexual selection on males. To document the covariance between mating number and offspring number for each sex, it is necessary to assign progeny to all parents, as well as identify mating and non-mating individuals. To document significant fitness gains by females through iteroparity, it is necessary to determine the relative magnitudes of male as well as female contributions to the total variance in relative fitness. We show how such data can be collected, how often they are collected, and we explain the circumstances in which selection favouring multiple mating by females can be strong or weak.
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Affiliation(s)
- Stephen M Shuster
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011-5640, USA.
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Meister B, Ursenbacher S, Baur B. Frequency of multiple paternity in the grass snake (Natrix natrix). AMPHIBIA-REPTILIA 2012. [DOI: 10.1163/156853812x634053] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Males can enhance their reproductive success through mating with multiple females. For females, however, one mating is usually sufficient to inseminate all of their ova. Females may benefit from multiple mating by producing genetically more diverse offspring, and by having the opportunity to choose sperm of the genetically most compatible male. We used five microsatellite loci to investigate the occurrence and frequency of multiple paternity in 11 clutches of the grass snake (Natrix natrix) in Switzerland. Using a very conservative estimate (program GERUD), two or more fathers were found in 27% of the clutches. However, based on the maximum likelihood estimate (program COLONY), multiple paternity occurred in 91% of the clutches with 2-5 contributing males per female. This is the first investigation demonstrating multiple paternity in a European natricine, with a frequency similar to those found in new world natricines.
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Affiliation(s)
- Barbara Meister
- Section of Conservation Biology, Department of Environmental Sciences, University of Basel, St. Johanns-Vorstadt 10, 4056 Basel, Switzerland
| | - Sylvain Ursenbacher
- Section of Conservation Biology, Department of Environmental Sciences, University of Basel, St. Johanns-Vorstadt 10, 4056 Basel, Switzerland
| | - Bruno Baur
- Section of Conservation Biology, Department of Environmental Sciences, University of Basel, St. Johanns-Vorstadt 10, 4056 Basel, Switzerland
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Winne CT, Willson JD, Whitfield Gibbons J. Drought survival and reproduction impose contrasting selection pressures on maximum body size and sexual size dimorphism in a snake, Seminatrix pygaea. Oecologia 2009; 162:913-22. [PMID: 19967417 DOI: 10.1007/s00442-009-1513-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2009] [Accepted: 10/27/2009] [Indexed: 10/20/2022]
Abstract
The causes and consequences of body size and sexual size dimorphism (SSD) have been central questions in evolutionary ecology. Two, often opposing selective forces are suspected to act on body size in animals: survival selection and reproductive (fecundity and sexual) selection. We have recently identified a system where a small aquatic snake species (Seminatrix pygaea) is capable of surviving severe droughts by aestivating within dried, isolated wetlands. We tested the hypothesis that the lack of aquatic prey during severe droughts would impose significant survivorship pressures on S. pygaea, and that the largest individuals, particularly females, would be most adversely affected by resource limitation. Our findings suggest that both sexes experience selection against large body size during severe drought when prey resources are limited, as nearly all S. pygaea are absent from the largest size classes and maximum body size and SSD are dramatically reduced following drought. Conversely, strong positive correlations between maternal body size and reproductive success in S. pygaea suggest that females experience fecundity selection for large size during non-drought years. Collectively, our study emphasizes the dynamic interplay between selection pressures that act on body size and supports theoretical predictions about the relationship between body size and survivorship in ectotherms under conditions of resource limitation.
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Affiliation(s)
- Christopher T Winne
- Savannah River Ecology Laboratory, University of Georgia, Drawer E, Aiken, SC 29802, USA.
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KING RICHARDB, JADIN ROBERTC, GRUE MICHAEL, WALLEY HARLAND. Behavioural correlates with hemipenis morphology in New World natricine snakes. Biol J Linn Soc Lond 2009. [DOI: 10.1111/j.1095-8312.2009.01270.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Dubey S, Brown GP, Madsen T, Shine R. Sexual selection favours large body size in males of a tropical snake (Stegonotus cucullatus, Colubridae). Anim Behav 2009. [DOI: 10.1016/j.anbehav.2008.09.037] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Weatherhead PJ, Kissner KJ, Sommerer SJ. Prenatal sex ratios and expression of sexually dimorphic traits in three snake species. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, COMPARATIVE EXPERIMENTAL BIOLOGY 2006; 305:603-9. [PMID: 16788914 DOI: 10.1002/jez.a.317] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Variation in intrauterine exposure to hormones associated with variation in the sex of litter mates has well-established and far-reaching effects on sexual development in some mammals. Research on this phenomenon in reptiles is scant, but suggests that lizards may follow the mammalian model whereas snakes may be affected differently. We examined sex-specific expression of four sexually dimorphic traits (tail length, head length, ventral scale count, swimming speed) in three species of snakes (Nerodia sipedon, Thamnophis sirtalis, T. sauritus) relative to litter sex ratios. We found little evidence that traits in either sex were masculinized or feminized in response to variation in litter sex ratio. The one significant result appeared best explained as a statistical artifact attributable to a single litter. Our results indicate that snakes are different from the one lizard studied to date. Unlike previous suggestions that prenatal hormonal mechanisms operate differently in snakes and lizards, however, the difference appears to be that development of sexually dimorphic traits in lizards is affected by litter sex ratios whereas in snakes it is not.
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