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Auld JR. The effects of diet and mating system on reproductive (and post-reproductive) life span in a freshwater snail. Ecol Evol 2018; 8:12260-12270. [PMID: 30598816 PMCID: PMC6303742 DOI: 10.1002/ece3.4689] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 10/09/2018] [Accepted: 10/12/2018] [Indexed: 02/05/2023] Open
Abstract
The length of the reproductive life span, along with the number/frequency/magnitude of reproductive events, quantifies an individual's potential contribution to the next generation. By examining reproductive life span, and distinguishing it from somatic life span, we gain insight into critical aspects of an individual's potential fitness as well as reproductive and somatic senescence. Additionally, differentiating somatic and reproductive life spans can provide insight into the existence of a post-reproductive period and factors that shape its duration. Given the known importance of diet and mating system on resource allocation, I reared individual freshwater snails (Physa acuta) from 22 full-sib families under a 2 × 2 factorial design that crossed mate availability (available [outcrossing] or not [selfing]) and diet (Spirulina or lettuce) and quantified aspects of the entire life history enabling me to distinguish reproductive and somatic life spans, determine the total number of reproductive events, and evaluate how the reproductive rate changes with age. Overall, mated snails experienced shorter reproductive and somatic life spans; a diet of Spirulina also shortened both reproductive and somatic life spans. A post-reproductive period existed in all conditions; its duration was proportional to somatic but not reproductive life span. I evaluate several hypotheses for the existence and duration of the post-reproductive period, including a novel hypothesis that the post-reproductive period may result from an increase in reproductive interval with age. I conclude that the post-reproductive period may be indicative of a randomly timed death occurring as the interval between reproductive events continues to increase. As such, a "post-reproductive" period can be viewed as a by-product of a situation where reproductive senescence outpaces somatic senescence.
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Affiliation(s)
- Josh R. Auld
- Department of BiologyWest Chester UniversityWest ChesterPennsylvania
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Bürkli A, Jokela J. Increase in multiple paternity across the reproductive lifespan in a sperm-storing, hermaphroditic freshwater snail. Mol Ecol 2017; 26:5264-5278. [PMID: 28605149 DOI: 10.1111/mec.14200] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 06/01/2017] [Accepted: 06/02/2017] [Indexed: 12/28/2022]
Abstract
Polyandry is a common phenomenon and challenges the traditional view of stronger sexual selection in males than in females. In simultaneous hermaphrodites, the physical proximity of both sex functions was long thought to preclude the operation of sexual selection. Laboratory studies suggest that multiple mating and polyandry in hermaphrodites may actually be common, but data from natural populations are sparse. We therefore estimated the rate of multiple paternity and its seasonal variability in the annual, sperm-storing, simultaneously hermaphroditic freshwater snail Radix balthica for the entire duration of the reproductive lifespan. We also tested whether multiple paternity was associated with clutch size or embryonic development. To obtain these data, we measured and genotyped 60 field-collected egg clutches using nine highly polymorphic microsatellite markers. Overall, 50% of the clutches had multiple fathers, and both the frequency (20-93% of clutches) and magnitude of multiple paternity (mean 1.3-3.8 fathers per clutch) substantially increased over time, probably because of extensive sperm storage. Most multiply sired clutches (83%) had a dominant father, but neither clutch size nor the proportion of developed embryos per clutch was associated with levels of multiple paternity. Both the evident promiscuity and the frequent skew of paternity shares suggest that sexual selection may be an important evolutionary force in the study population.
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Affiliation(s)
- Anja Bürkli
- Department of Aquatic Ecology, EAWAG, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland.,ETH Zurich, D-USYS, Institute of Integrative Biology, Zürich, Switzerland
| | - Jukka Jokela
- Department of Aquatic Ecology, EAWAG, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland.,ETH Zurich, D-USYS, Institute of Integrative Biology, Zürich, Switzerland
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Auld JR, Helker AD, Kolpas A. Consequences of mating and predation risk for longevity in a freshwater snail: abstinence makes the heart beat longer. J Evol Biol 2016; 29:2539-2544. [PMID: 27591368 DOI: 10.1111/jeb.12976] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Revised: 08/04/2016] [Accepted: 08/28/2016] [Indexed: 11/26/2022]
Affiliation(s)
- J. R. Auld
- Department of Biology West Chester University West Chester PA USA
| | - A. D. Helker
- Department of Mathematics West Chester University West Chester PA USA
| | - A. Kolpas
- Department of Mathematics West Chester University West Chester PA USA
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Noël E, Chemtob Y, Janicke T, Sarda V, Pélissié B, Jarne P, David P. Reduced mate availability leads to evolution of self-fertilization and purging of inbreeding depression in a hermaphrodite. Evolution 2016; 70:625-40. [DOI: 10.1111/evo.12886] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 02/02/2016] [Accepted: 02/05/2016] [Indexed: 12/30/2022]
Affiliation(s)
- Elsa Noël
- Centre d'Ecologie Fonctionnelle et Evolutive (CEFE), UMR 5175, CNRS, Université de Montpellier; Université Paul Valéry Montpellier; EPHE, 1919 route de Mende 34293 Montpellier Cedex 5 France
| | - Yohann Chemtob
- Centre d'Ecologie Fonctionnelle et Evolutive (CEFE), UMR 5175, CNRS, Université de Montpellier; Université Paul Valéry Montpellier; EPHE, 1919 route de Mende 34293 Montpellier Cedex 5 France
- Laboratoire Interdisciplinaire des Energies de Demain (LIED), UMR 8236; Université Paris Diderot; UFR Physique, Bâtiment Condorcet, 10 Rue A. Domon et L. Duquet 75205 Paris Cedex 13 France
| | - Tim Janicke
- Centre d'Ecologie Fonctionnelle et Evolutive (CEFE), UMR 5175, CNRS, Université de Montpellier; Université Paul Valéry Montpellier; EPHE, 1919 route de Mende 34293 Montpellier Cedex 5 France
| | - Violette Sarda
- Centre d'Ecologie Fonctionnelle et Evolutive (CEFE), UMR 5175, CNRS, Université de Montpellier; Université Paul Valéry Montpellier; EPHE, 1919 route de Mende 34293 Montpellier Cedex 5 France
| | - Benjamin Pélissié
- Centre d'Ecologie Fonctionnelle et Evolutive (CEFE), UMR 5175, CNRS, Université de Montpellier; Université Paul Valéry Montpellier; EPHE, 1919 route de Mende 34293 Montpellier Cedex 5 France
| | - Philippe Jarne
- Centre d'Ecologie Fonctionnelle et Evolutive (CEFE), UMR 5175, CNRS, Université de Montpellier; Université Paul Valéry Montpellier; EPHE, 1919 route de Mende 34293 Montpellier Cedex 5 France
| | - Patrice David
- Centre d'Ecologie Fonctionnelle et Evolutive (CEFE), UMR 5175, CNRS, Université de Montpellier; Université Paul Valéry Montpellier; EPHE, 1919 route de Mende 34293 Montpellier Cedex 5 France
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Janicke T, Chapuis E. Condition dependence of male and female reproductive success: insights from a simultaneous hermaphrodite. Ecol Evol 2016; 6:830-41. [PMID: 26865970 PMCID: PMC4739575 DOI: 10.1002/ece3.1916] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 12/03/2015] [Accepted: 12/09/2015] [Indexed: 11/22/2022] Open
Abstract
Sexually selected traits are predicted to show condition dependence by capturing the genetic quality of its bearer. In separate‐sexed organisms, this will ultimately translate into condition dependence of reproductive success of the sex that experiences sexual selection, which is typically the male. Such condition dependence of reproductive success is predicted to be higher in males than females under conditions promoting intense sexual selection. For simultaneous hermaphrodites, however, sex allocation theory predicts that individuals in poor condition channel relatively more resources into the male sex function at the expense of the female function. Thus, male reproductive success is expected to be less condition dependent than female reproductive success. We subjected individuals of the simultaneously hermaphroditic snail Physa acuta to two feeding treatments to test for condition dependence of male and female reproductive success under varying levels of male–male competition. Condition dependence was found for female, but not for male, reproductive success, meaning that selection on condition is relatively stronger through the female sex function. This effect was consistent over both male–male competition treatments. Decomposition of male and female reproductive performance revealed that individuals in poor condition copulated more in their male role, indicating an increased male allocation to mate acquisition. These findings suggest that sex‐specific condition dependence of reproductive success is at least partially driven by condition‐dependent sex allocation. We discuss the implications of condition‐dependent sex allocation for the evolution of sexually selected traits in simultaneous hermaphrodites.
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Affiliation(s)
- Tim Janicke
- Centre d'Ecologie Fonctionnelle et Evolutive UMR 5175 CNRS Université de Montpellier Université Paul-Valéry Montpellier Ecole Pratique des Hautes Etudes Montpellier Cedex 05 France
| | - Elodie Chapuis
- Centre d'Ecologie Fonctionnelle et Evolutive UMR 5175 CNRS Université de Montpellier Université Paul-Valéry Montpellier Ecole Pratique des Hautes Etudes Montpellier Cedex 05 France; Institut de recherche pour le développement UMR IPME (IRD, Université de Montpellier, CIRAD) 911 avenue Agropolis BP 6450134394 Montpellier Cedex 5 France; UMR "Peuplements Végétaux et Bio-agresseurs en Milieu Tropical "CIRAD-3P7 Chemin de l'IRAT Ligne Paradis 97410 Saint Pierre La Réunion France
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Auld JR, Houser R. Age-dependent effects of predation risk on reproductive success in a freshwater snail. Evolution 2015; 69:2793-8. [PMID: 26345490 DOI: 10.1111/evo.12769] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 08/20/2015] [Accepted: 08/24/2015] [Indexed: 01/18/2023]
Abstract
Reproductive performance is often age-dependent, showing patterns of improvement and/or senescence as well as trade-offs with other traits throughout the lifespan. High levels of extrinsic mortality (e.g., from predators) have been shown to sometimes, but not always, select for accelerated actuarial senescence in nature and in the lab. Here, we explore the inductive (i.e., plastic) effects of predation risk (i.e., nonlethal exposure to chemical cues from predators) on the reproductive success of freshwater snails (Physa acuta). Snails were reared either in the presence or absence of chemical cues from predatory crayfish and mated early in life or late in life (a 2 × 2 factorial design); we measured egg hatching and early post-hatching survival of their offspring. Both age and predation risk reduced reproductive success, illustrating that predation risk can have a cross-generational effect on the early survival of juveniles. Further, the decline in reproductive success was over three times faster under predation risk compared to the no-predator treatment, an effect that stemmed from a disproportionate, negative effect of predation risk on the post-hatching survival instead of hatching rate. We discuss our results in terms of a hypothesized consequence of elevated stress hormone levels.
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Affiliation(s)
- Josh R Auld
- Department of Biology, West Chester University, West Chester, Pennsylvania, 19383.
| | - Ryan Houser
- Department of Biology, West Chester University, West Chester, Pennsylvania, 19383
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Auld JR, Henkel JF. Diet alters delayed selfing, inbreeding depression, and reproductive senescence in a freshwater snail. Ecol Evol 2014; 4:2968-77. [PMID: 25165532 PMCID: PMC4130452 DOI: 10.1002/ece3.1146] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 05/30/2014] [Accepted: 06/02/2014] [Indexed: 11/08/2022] Open
Abstract
Reproductive success is a critical fitness attribute that is directly influenced by resource availability. Here, we investigate the effects of diet-based resource availability on three interrelated aspects of reproductive success: a change in mating system based on mate availability, consequent inbreeding depression, and the deterioration of reproductive efficiency with age (senescence). We employed a factorial experimental design using 22 full-sib families of the hermaphroditic freshwater snail Physa acuta to explore these interactions. Individual snails were reared in one of two mate-availability treatments (isolated [selfing] or occasionally paired [outcrossing]) and one of two diet treatments (boiled lettuce or Spirulina, an algae that is rich in protein, vitamins, and minerals). Spirulina-fed snails initiated reproduction at a 13% earlier age and 7% larger size than lettuce-fed snails. Spirulina also resulted in a 30% reduction in the time delay before selfing. Compared to lettuce, a diet of Spirulina increased inbreeding depression by 52% for egg hatching rate and 64% for posthatching juvenile survival. Furthermore, Spirulina led to a 15-fold increase in the rate of reproductive senescence compared with a diet of lettuce. These transgenerational, interactive effects of diet on inbreeding depression and reproductive senescence are discussed in the context of diet-induced phenotypic plasticity.
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Affiliation(s)
- Josh R Auld
- Department of Biology, West Chester University 750 S. Church St., West Chester, Pennsylvania, 19383
| | - John F Henkel
- Department of Biology, West Chester University 750 S. Church St., West Chester, Pennsylvania, 19383
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